JP2007134321A - Light emitting apparatus, method for manufacturing same, exposure apparatus, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting apparatus that allows sealing to be carried out through a simple step using a thermosetting resin as a material for a sealing part, and that ensures a sufficient gas barrier property in spite of the use of the simple sealing step without causing any damage to an organic electroluminescent element resulting from heat, and to provide a method of manufacturing this light emitting apparatus, an exposure apparatus using this light emitting apparatus, and an image forming apparatus equipped with this light emitting apparatus. <P>SOLUTION: The apparatus is configured to include a substrate 2, a plurality of light emitting parts LS formed using a polymer organic electroluminescent material on the substrate 2, an electrode (cathode 7) covering the light emitting parts LS, and a sealing part 10 that is composed of a thermosetting resin and covers a region wider than at least this electrode (cathode 7). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting device provided with an organic electroluminescence element, an exposure device incorporating the light emitting device, and an image forming apparatus equipped with the exposure device.

  An electroluminescent element is a light-emitting device that uses electroluminescence of a solid fluorescent substance. Currently, an inorganic electroluminescent element using an inorganic material as a luminescent material has been put into practical use, and is used for backlights and flat displays of liquid crystal displays. Some applications are being developed. However, since the voltage required for light emission of the inorganic electroluminescent element is as high as 100 V or more and it is difficult to emit blue light, it is difficult to achieve full color using the three primary colors of RGB. In addition, since the inorganic electroluminescent element has a very large refractive index of the material used as a light emitter, it is strongly affected by total reflection at the interface, and the light extraction efficiency into the air for actual light emission is about 10 to 20%. It is difficult to achieve high efficiency.

On the other hand, research on electroluminescent devices using organic materials has attracted attention for a long time, and various studies have been made. However, since the luminous efficiency is very low, full-scale practical research has not progressed. However, in 1987, Kodak's C.I. W. Tang et al. Proposed an organic electroluminescence device having a function-separated stacked structure in which an organic material constituting a light-emitting layer is divided into a hole transport layer and a light-emitting layer, despite a low voltage of 10 V or less. not 1000 cd / m ² or more high luminance can be obtained revealed (see non-Patent Document 1).

  Since then, organic electroluminescence elements have attracted a great deal of attention, and research on organic electroluminescence elements having a similar function-separated layered structure has been actively conducted, especially for the practical application of organic electroluminescence elements. High efficiency and longevity, which are indispensable for this, have been fully studied. In recent years, displays using organic electroluminescence elements have been realized.

  FIG. 12 is a cross-sectional view showing the structure of a conventional organic electroluminescence element.

  Hereinafter, the structure of a conventional general organic electroluminescence element will be described with reference to FIG.

As shown in FIG. 12, the organic electroluminescence element 11 includes an anode 13 made of a transparent conductive film such as ITO formed on a glass substrate 12 by a sputtering method, a resistance heating vapor deposition method, or the like. N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-diphenyl-4,4′-diamine (hereinafter abbreviated as TPD) formed by resistance heating vapor deposition or the like. ), An organic material layer 15 made of 8-hydroxyquinoline aluminum (hereinafter abbreviated as Alq ₃ ) formed on the hole transport layer 14 by resistance heating vapor deposition, and the like, and an organic material And a cathode 17 made of a metal film having a thickness of about 100 to 300 nanometers formed on the layer 15 by a resistance heating vapor deposition method or the like.

  The hole transport layer 14 and the organic material layer 15 are collectively referred to simply as a light emitting layer 16 for convenience. In this case, the light emitting layer 16 includes, in addition to the hole transport layer 14 and the organic material layer 15, a hole injection layer, an electron injection layer, an electron transport layer, and an electron block layer (both not shown). Also good. The following explanation is also based on this example.

  Reference numeral 18 denotes a sealing portion made of glass having a bathtub shape, for example. The sealing portion 18 is provided so as to cover at least the entire surface of the organic electroluminescence element 11, and the outer peripheral portion thereof is bonded to the glass substrate 12 or the like using an adhesive. As will be described later, since the organic electroluminescence element 11 in which the light emitting layer 16 is composed of the low-molecular organic material layer 15 dislikes high temperature, generally, a photo-curing resin that is cured by irradiating, for example, ultraviolet rays is often used as an adhesive. Has been.

  When a DC voltage or a DC current is applied through an electric circuit (not shown) with the anode 13 of the organic electroluminescence element 11 having the above-described configuration as a positive electrode and the cathode 17 as a negative electrode, the anode 13 passes through the hole transport layer 14. Thus, holes are injected into the organic material layer 15 and electrons are injected from the cathode 17 into the organic material layer 15. As a result, in the organic material layer 15 constituting the light-emitting layer 16 sandwiched between the anode 13 and the cathode 17, recombination of holes and electrons occurs, and the excitons generated thereby shift from the excited state to the ground state. In this case, a light emission phenomenon occurs (a portion sandwiched between at least the anode 13 and the cathode 17 and substantially contributing to light emission is hereinafter referred to as a “light emitting portion”).

  In such an organic electroluminescence element 11, light emitted from the phosphor in the organic material layer 15 constituting the light emitting part is emitted in all directions centering on the phosphor, and the hole transport layer 14 and the anode 13 are emitted. The light is emitted from the light extraction direction (direction of the glass substrate 12) into the air via the glass substrate 12. Alternatively, the light is once reflected in the direction opposite to the light extraction direction, reflected by the cathode 17 and emitted to the air via the light emitting layer 16, the anode 13, and the glass substrate 12. As described above, the organic electroluminescence element 11 has a very simple structure, and is attracting attention as a technology that can be mass-produced and can be expected to reduce cost and increase the area of a display device such as a display. .

  However, on the other hand, as one of the problems of the organic electroluminescence element 11, when affected by moisture, the light emitting region shrinks (shrinks) with time, or a non-light emitting portion (dark spot) is generated in the light emitting region. It is known. In order to prevent the occurrence and expansion of shrinking and dark spots, it is necessary to keep the organic electroluminescent element 11 in a low humidity state. As described above, the organic electroluminescent element 11 is sealed by the sealing portion 18 such as glass. Methods such as sealing and vacuuming the internal space of the sealing region or filling with an inert gas of low humidity are used. In order to further enhance the sealing effect, a desiccant may be provided in the bathtub-like space.

  Recently, for example, a so-called gas barrier laminate having a laminated structure of an organic material layer made of resin and an inorganic material layer made of metal oxide or the like is used as the sealing portion 18 of the organic electroluminescence element 11. As an example of such a gas barrier laminate, a manufacturing method disclosed in (Patent Document 1) is known. In (Patent Document 1), “(Omitted) Many studies have been made on inorganic films, single layers of organic films, or stacking of organic / inorganic film gas barrier layers. As a result, a metal oxide film, a metal nitride film or a metal film is provided on a substrate such as a film, and an organic layer made of a thermosetting resin is laminated thereon. In the gas barrier laminate having the second metal oxide film, the metal nitride film, or the metal film, the first curing is performed in the range of 120 ° C. to 180 ° C. immediately after the organic layer as the intermediate layer is laminated, After the second metal oxide film, the metal nitride film, or the metal film is provided, the second thermosetting is performed in the range of 180 ° C. to 240 ° C., whereby an inorganic film, a single layer of the organic film, or an organic film / inorganic Membrane gas In such stacking the rear layer expression is to be able to acquire a gas barrier property is difficult.

As another approach related to the sealing technology, for example, a manufacturing method of a light emitting device disclosed in (Patent Document 2) is known. In (Patent Document 2), as a sealing adhesive for laminating the glass substrate 12 and the sealing portion 18, a photothermal conversion substance (that is, a substance that absorbs infrared rays or near infrared rays) into a thermosetting (or thermoplastic) resin. ) And irradiating a laser beam to this to locally heat the portion where the sealing portion is to be bonded, so that the organic electroluminescence device generally having only heat resistance of 100 ° C. to 120 ° C. is not damaged. It is said that sealing can be performed.
JP 2004-181793 A JP 2001-237066 A Tan (C.W. Tang), S.A. Vanslyke, "Appl. Phys. Lett." (USA), Vol. 51, 1987, p. 913

  Since the manufacturing process of organic electroluminescent elements is simple, it is said that applications such as light-emitting devices equipped with organic electroluminescent elements and exposure apparatuses using organic electroluminescent elements as light sources are advantageous for cost reduction. . However, in the manufacturing process, the presence of a process having a plurality of temperature controls as in (Patent Document 1) in the sealing process reduces the productivity, which leads directly to an increase in cost. Regarding the manufacturing cost, the manufacturing method of performing local sealing using laser light (Patent Document 2) also has a problem in terms of cost due to the large manufacturing equipment.

  In an actual configuration of the light emitting device, for example, an organic electroluminescence element, for example, a driving circuit constituted by a TFT, a lead wiring, and the like are formed and arranged on a substrate constituting the light emitting device. It will be coated. The above (Patent Document 1) and (Patent Document 2) do not even suggest the importance of this, but the sealing performance such as the so-called gas barrier property greatly depends on the surface state of the structure to be bonded. Therefore, it depends on which structure the outer periphery of the sealing portion comes into contact with and adheres to, and is an important element for surely sealing.

  The present invention is capable of sealing in a simple process using a thermosetting resin as a material for the sealing part, and does not damage the organic electroluminescence element due to heat, and further simplifies the sealing process. In addition to providing a light-emitting device that has a sufficient barrier property against moisture and gas despite the use, a method for manufacturing the light-emitting device, and a highly reliable exposure apparatus incorporating the light-emitting device. An object of the present invention is to provide an on-board high-quality image forming apparatus.

  The light-emitting device of the present invention has been made in view of the above problems, and includes a substrate, a plurality of light-emitting portions formed on the substrate using a polymer organic electroluminescent material, and an electrode for supplying power to the light-emitting portion. And a sealing portion made of a thermosetting resin covering at least a wider area than this electrode.

  The polymer organic electroluminescent material has long molecular chains intricately entangled with each other, and crystallization does not proceed even when exposed to a high temperature environment. Therefore, even if a sealing portion made of a thermosetting resin is provided for a plurality of light emitting portions formed using a polymer organic electroluminescence material, the organic electroluminescence element is generated by heat applied when the sealing portion is cured. Will not take damage.

  Also, since the barrier property against moisture and gas of thermosetting resin is generally superior to that of ultraviolet curable resin, it is possible to perform sealing in a simple process, and atmosphere even with a simple configuration. It is possible to ensure a sufficient barrier property against moisture and gas therein.

  Further, by covering a wider area than the electrode covering the organic electroluminescent element with this sealing portion, the sealing portion does not straddle between the electrode and another structure formed under the electrode, and moisture or gas It becomes possible to further improve the barrier property against the above. Moreover, since the electrode covering the organic electroluminescence element is composed of a metal material such as aluminum or silver (that is, a material having a high barrier property) as described later, it is very coupled with the good barrier property of the thermosetting resin. High sealing performance can be exhibited.

  The light-emitting device of the present invention includes a substrate, a plurality of light-emitting portions formed on the substrate using a polymer organic electroluminescent material, an electrode for supplying power to the light-emitting portion, and at least a wider range than the electrodes. And a sealing portion made of a thermosetting resin to be covered. The polymer organic electroluminescent material has long molecular chains intricately entangled with each other, and crystallization does not proceed even when exposed to a high temperature environment. Therefore, even if a sealing portion made of a thermosetting resin is provided for a plurality of light emitting portions made of a polymer organic electroluminescent material, the organic electroluminescence element is damaged by the heat applied when the sealing portion is cured. There is nothing. In general, the barrier property against moisture and gas of thermosetting resin is superior to that of ultraviolet curable resin, so it is possible to perform sealing in a simple process. It is possible to ensure a sufficient barrier property against moisture and gas therein. Furthermore, by covering a wider area than the electrode covering the organic electroluminescence element with this sealing part, the sealing part does not straddle the electrode and other parts, and it is possible to further improve the barrier property against moisture and gas It becomes.

  In the present invention, a protective part that covers at least the entire surface of the electrode is formed between the electrode that covers the light emitting part and the sealing part, and the outer peripheral part of the sealing part is bonded to the protective part. This protective part covers the entire surface of the electrode covering the entire surface of the light emitting part, improves the barrier property against moisture and gas, and forms a uniform base with no irregularities on the sealing part, and the outer peripheral part of the sealing part Therefore, not only the sealing performance but also the reliability against external force can be improved.

  Further, the present invention has a wiring part for inputting at least a control signal related to driving of the light emitting part on the substrate, the protection part is configured to cover the wiring part, and the sealing part is bonded to the protection part. It is configured. As a result, the step of the wiring portion arranged on the substrate can be made uniform with no unevenness by the protective portion, and the adhesive strength at the outer peripheral portion of the sealing portion can be improved.

  In the present invention, a pixel restricting portion for restricting the light emitting region of the light emitting portion is provided on the substrate, and the pixel restricting portion and the protecting portion are made of the same material. As a result, the light emitting portion and the electrode are sandwiched between the pixel restricting portion and the protecting portion made of the same material, so that the structure of the joint portion between the pixel restricting portion and the protecting portion is stabilized, and the sealing performance can be further improved. It becomes possible.

  In the present invention, the protection part and the pixel regulation part are made of metal oxide or metal nitride. As a result, a very stable film can be obtained by a simple method such as sputtering. In addition, since metal oxides and metal nitrides have an extremely dense structure, the protective part can fill the unevenness of the underlying structure without any gaps, and reliably prevent moisture and gas from entering through the gaps. can do.

  In the present invention, a protective part that covers at least a wider area than the electrode is formed between the electrode and the sealing part, and the sealing part is configured to cover a wider area than the protective part. As a result, double sealing is performed by the protective part and the sealing part, so that the sealing performance can be improved.

  In the present invention, the protective part is made of a hygroscopic material. As a result, a trace amount of moisture that has passed through the sealing portion is captured by the hygroscopic material before reaching the light emitting portion, so that the sealing performance can be further improved.

  According to the present invention, a pixel restricting portion for restricting the light emitting region of the light emitting portion is provided on the substrate, and the outer peripheral portion of the sealing portion is bonded to the pixel restricting portion. The pixel restricting portion is formed to be sufficiently thick to ensure insulation, and the surface of the pixel restricting portion exhibits a uniform surface with no unevenness due to this thickness, so that the adhesive strength at the outer peripheral portion of the sealing portion becomes strong, and sealing is performed. It is possible to improve not only the stopping performance but also the reliability against external force.

  Moreover, this invention comprises the sealing part with the epoxy resin whose glass transition temperature is 140 to 180 degreeC. In general, the higher the glass transition temperature of the thermosetting resin, the higher the hardness of the cured resin, but the adhesive strength decreases, causing peeling from the substrate due to external or internal stress. On the other hand, a resin having a low glass transition temperature has a low adhesion strength inside the resin, resulting in a decrease in confidentiality. Taking these into consideration, by setting the glass transition temperature of the sealing portion within the above range, both adhesiveness and confidentiality can be achieved.

  Moreover, this invention is comprised so that the sealing part may contain the inorganic filler which has cleavage property. Cleavage means that a crystal is easily cracked or peeled off in a certain direction and a smooth surface (cleavage surface) appears, whereby the intrusion path of moisture, gas, etc. that permeate the inside of the resin constituting the sealing portion. Becomes very long, and the sealing performance can be greatly improved.

  In the present invention, a driving circuit composed of TFTs for driving the light emitting portion is provided on a substrate, and the driving circuit is covered with a sealing portion. If a crack or the like occurs in the drive circuit due to external stress, etc., the light emitting device is fatally damaged such that it cannot be driven, but the drive circuit is protected from external stress by covering the drive circuit part with a sealing part. The reliability of the light emitting device can be improved.

  In the present invention, the sealing portion is configured to contain an inorganic porous material (zeolite) having water absorption. As a result, moisture, gas, and the like that permeate through the resin constituting the sealing portion are adsorbed on the surface of the inorganic porous material before reaching the light emitting portion, so that the sealing performance can be greatly improved. .

  In the present invention, the sealing portion is configured so that the filling amount of the inorganic porous material having water absorption is equal to or greater than the filling amount of the inorganic filler having cleavage property. As a result, the infiltration path of moisture, gas, etc. that permeates the resin inside the sealing part becomes very long and is adsorbed on the surface of the inorganic porous material before reaching the light emitting part, greatly improving the sealing performance. Can be improved.

  Moreover, this invention comprises the sealing part in thickness of 50 micrometers or more. Since the protective part is made of a material having a dense structure such as silicon oxide, which is a metal oxide, or silicon nitride, which is a metal nitride, the protective part can be made thin. The time can be shortened. As a result, when the light emitting device is applied to an exposure apparatus mounted on an image forming apparatus for personal use, sufficient sealing performance can be ensured.

  An exposure apparatus according to the present invention includes the above-described light-emitting device and is configured so that a plurality of light-emitting units can be turned on / off independently. Since the light-emitting device of the present invention exhibits a sufficient sealing performance with a very simple structure, the exposure apparatus equipped with the light-emitting apparatus has high reliability over a long period of time, and further reduces the size and cost of the exposure apparatus. Can be realized.

  In the present invention, the light emitting unit is driven by an active matrix circuit provided on a substrate. Unlike the passive matrix circuit, the electrode (cathode described later) in the active matrix circuit does not need to be formed in a stripe shape, and a large number of spaces are not formed between the electrode and the sealing portion, so that the sealing performance can be improved. It becomes possible.

  The method for manufacturing a light emitting device of the present invention includes a step of forming a plurality of light emitting portions on a substrate using a polymer organic electroluminescent material, a step of forming an electrode covering the light emitting portion, and at least a wider area than the electrodes. It has the sealing process sealed with the sealing part comprised from curable resin. The polymer organic electroluminescent material has long molecular chains intricately entangled with each other, and crystallization does not proceed even when exposed to a high temperature environment. Therefore, even if a sealing portion made of a thermosetting resin is provided for a plurality of light emitting portions made of a polymer organic electroluminescent material, the organic electroluminescence element is damaged by the heat applied when the sealing portion is cured. There is nothing. In general, the barrier property against moisture and gas of thermosetting resin is superior to that of ultraviolet curable resin, so it is possible to perform sealing in a simple process. It is possible to ensure a sufficient barrier property against moisture and gas therein. Furthermore, by covering a wider area than the electrode covering the organic electroluminescence element with this sealing part, the sealing part does not straddle the electrode and other parts, and it is possible to further improve the barrier property against moisture and gas It becomes.

  Further, the present invention includes a step of removing the organic electroluminescent material at a position corresponding to at least the outer peripheral portion of the sealing portion after applying the polymer organic electroluminescent material on the substrate. This makes it possible to prevent moisture, gas, and the like from entering from the outside through the layer made of the organic electroluminescent material.

  The present invention also includes a step of performing a heat treatment after applying a polymer organic electroluminescent material on a substrate, and the temperature of the heat treatment (baking temperature) is set higher than the temperature at which the thermosetting resin is subsequently cured. It is. As a result, an organic solvent such as toluene or xylene in which the polymer organic electroluminescent material is dissolved is sufficiently volatilized, and the performance of the organic electroluminescent element as the light emitting portion can be stabilized.

  In the sealing process, at least two stages of curing temperatures are provided, and the curing temperature is set higher as the later curing temperature. This makes it possible to reliably cure the sealing portion. In addition, the temperature for curing the sealing portion is set to be lower than the above-described baking temperature, and the light-emitting portion is reduced by the thermal expansion of the structure by relaxing the temperature condition necessary for processing as the manufacturing process becomes later. It is possible to minimize factors that deteriorate the yield, such as cracks.

  An image forming apparatus of the present invention includes the above-described exposure apparatus, a photoreceptor on which a latent image is formed by the exposure apparatus, a developing station that develops and visualizes the latent image formed on the photoreceptor, The image forming apparatus includes a transfer unit that transfers an image developed by the developing station to a recording sheet, and a fixing unit that fixes the image transferred by the transfer unit. Since the exposure apparatus of the present invention has features such as high reliability, small size, and low cost, an image forming apparatus equipped with the exposure apparatus can maintain high image quality over a long period of time, and the image forming apparatus Miniaturization and cost reduction can be achieved.

  Hereinafter, the light emitting device according to the present invention will be described in detail. In all the following examples, the light emitting element substrate 70 on which various structures are formed corresponds to the light emitting device according to the present invention.

Example 1
Embodiment 1 of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a structure of an organic electroluminescence element 1 in a light emitting element substrate of Example 1 of the present invention. Hereinafter, the structure of the organic electroluminescence element 1 in Example 1 will be described in detail with reference to FIG.

  In FIG. 1, reference numeral 1 denotes an organic electroluminescence element.

<Board>
2 is a colorless and transparent substrate. Examples of the substrate 2 include inorganic oxide glass and inorganic fluoride such as transparent or translucent soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz glass. Inorganic glass such as glass can be used.

Other materials can be used as the substrate 2, for example, transparent or translucent polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyether sulfone, polyvinyl fluoride, polypropylene, polyethylene, polyacrylate, amorphous polyolefin, Polymer films using polymer materials such as fluororesin polysiloxane and polysilane, or transparent or translucent chalcogenoid glasses such as As ₂ S ₃ , As ₄₀ S ₁₀ , S ₄₀ Ge ₁₀ , ZnO, Nb ₂ When taking out light emitted from a material such as metal oxides and nitrides such as O, Ta ₂ O ₅ , SiO, Si ₃ N ₄ , HfO ₂ , TiO ₂ , or light emitting region without passing through the substrate, Opaque silicon, germanium, silicon carbide, gallium arsenide, nitrogen A semiconductor substrate such as gallium, or the above-mentioned transparent substrate material containing a pigment, a metal material whose surface is insulated, and the like can be appropriately selected and used, and a laminated substrate in which a plurality of substrate materials are laminated is used. You can also.

  In the following description, structures such as the TFT 102 and the organic electroluminescence element 1 formed on the substrate 2 will be described. However, the substrate 2 and all the structures formed thereon are integrated to emit light. It is called the element substrate 70 (as described above, this is the “light emitting device”).

<TFT>
Reference numeral 101 denotes a base coat layer formed on the surface A on the substrate 2, and is configured by stacking, for example, silicon nitride and silicon oxide. A TFT 102 made of polycrystalline silicon (polysilicon) is formed on the base coat layer 101. In the first embodiment, polycrystalline silicon is used as the TFT 102, but amorphous silicon (amorphous silicon) may be used. Amorphous silicon is disadvantageous compared to the low mobility of when constituting a transistor (0.5 cm ² / about Vs) design rules and high mobility in terms of the driving frequency polycrystalline silicon (100~200cm ² / Vs) However, the manufacturing process is inexpensive and has a cost advantage.

  Reference numeral 103 denotes a gate insulating layer made of silicon oxide having a thickness of, for example, about 100 nanometers, and insulates the TFT 102 and the gate electrode 104 made of a metal such as molybdenum at a predetermined interval. An intermediate layer 105 is formed by laminating silicon oxide and silicon nitride, for example, and has a total thickness of about 350 nanometers. The intermediate layer 105 covers the gate electrode 104 and supports a source electrode 106 and a drain electrode 107 made of a metal such as Al along the surface. The source electrode 106 and the drain electrode 107 are connected to the TFT 102 through contact holes provided in the intermediate layer 105 and the gate insulating layer 103, and a predetermined potential difference is applied between the source electrode 106 and the drain electrode 107. By applying a predetermined potential to the gate electrode 104, the TFT 102 operates as a switching transistor.

  Reference numeral 108 denotes a TFT protective layer made of silicon nitride or the like, which completely covers the source electrode 106 and forms an opening, that is, a contact hole 109 in a part of the drain electrode 107. Usually, the TFT protective layer 108 is formed to a thickness of about 300 nanometers. However, if an overcoat layer (not shown) made of resin or the like is not formed on the upper surface, the TFT protective layer 108 may be formed a little thicker.

Reference numeral 3 denotes an anode formed on the TFT protective layer 108. In Example 1, ITO (indium tin oxide) is used. As the anode 3, in addition to ITO, IZO (zinc-doped indium oxide), ATO (Sb-doped SnO ₂ ), AZO (Al-doped ZnO), ZnO, SnO ₂ , In ₂ O _{3 and the} like can be used. . The anode 3 can be formed by a vacuum deposition method or the like, but is preferably formed by a sputtering method or a CVD method (Chemical Vapor Deposition). The anode 3 is connected to the drain electrode 107 through a contact hole 109.

  As shown in FIG. 1, the TFT 102, which is a drive circuit for driving the organic electroluminescence element 1, is completely covered with a protective part 9 and a sealing part 10. When a crack or the like is generated in the drive circuit due to external stress or the like, the light emitting device is fatally damaged such that it cannot be driven. However, the drive circuit portion is covered with the protective portion 9 and the sealing portion 10 so that the drive circuit is formed. External stress does not directly act on the TFT 102, and the reliability of the light emitting device can be improved.

<Pixel restriction section>
As defined in the description in the background art, in the following description, a portion that is sandwiched between at least the anode and the cathode and substantially contributes to light emission is referred to as a “light emitting portion”. In the case where illustration is required, it will be described as “light emitting unit LS”.

  Reference numeral 8 denotes a pixel restricting portion that restricts the position, shape, size, and the like of the light emitting portion LS that contributes to light emission by covering a part of the anode 3. In the first embodiment, silicon nitride is used as the pixel restricting portion 8, but silicon oxide may be used. The pixel restricting portion 8 is formed by, for example, uniformly forming these metal oxides or metal nitrides by vapor deposition or sputtering, and then patterning, developing, and etching using a photomask. The pixel restricting portion 8 may be formed by a sputtering method through a mask. The thickness of the pixel restricting portion 8 composed of these metal oxides or metal nitrides is preferably 50 nanometers or more and 2 micrometers or less. When the thickness of the pixel restricting portion 8 is less than 50 nanometers, a defect is generated in the film, and the probability that a portion that should not originally emit light emits light increases.

  As will be described in detail later in other embodiments, in the configuration in which the outer peripheral portion of the sealing portion 10 is bonded to the pixel restricting portion 8 at the time of sealing, if the pixel restricting portion 8 is defective, moisture or gas In view of this, the thickness of the pixel restricting portion 8 is desirably 50 nm or more.

  On the other hand, when the thickness of the pixel restricting portion 8 exceeds 2 micrometers, a step is increased between the anode 3 and the pixel restricting portion 8 at the end of the pixel restricting portion 8 protruding to the anode 3 side. The uniformity of the light emission luminance in the formed light emitting part LS is impaired.

  There are various reasons why the light emitting part LS is configured by restricting the anode 3 by the pixel restricting part 8. For example, when an exposure apparatus is assumed, it is performed in order to accurately determine the position and shape of the light emitting surface. Of course, since the organic electroluminescence element 1 emits light at the overlapping portion of the anode 3 and the cathode 7 facing each other according to the principle described above, the shape and the like of the light emitting portion LS can be regulated by the position and shape of the anode 3 and the cathode 7. In an exposure apparatus, for example, the application side demands that the size and arrangement pitch of the light emitting portions LS be extremely small {for example, 600 dpi (dot per inch), that is, the light emitting portion LS is in a direction perpendicular to the paper surface of FIG. In the direction), which is arranged at a pitch of 42.3 micrometers}, so that it is restricted by the electrodes such as the anode 3 and the cathode 7 in the position of the manufacturing process. High accuracy is required for the combination. Further, the individual electrode lines become too thin, resulting in a problem that the resistance value increases. Therefore, a method is generally used in which an electrode having a certain width is produced so that the resistance value does not increase, and a part thereof is regulated by the pixel regulating unit 8 to regulate the light emitting surface.

<Light emitting layer>
Reference numeral 6 denotes a light emitting layer. In Example 1, a polymer organic electroluminescent material described later is used as the light-emitting layer 6, and the light-emitting layer 6 is formed by applying a spin coating method, which is one of the wet processes capable of reducing the cost with a simple process. is doing.

  In general, a polymer organic electroluminescent material refers to an organic electroluminescent material formed by a wet process such as a spin coat method, and a low molecular organic electroluminescent material is formed by a dry process such as a vacuum evaporation method. Strictly speaking, it refers to an organic electroluminescent material, but strictly speaking, a material that cannot be applied with a dry process such as a vacuum deposition method is called a polymer organic electroluminescent material. The reason why the vacuum deposition method cannot be applied to the polymer organic electroluminescent material is that the polymer organic electroluminescent material undergoes self-molecular motion before being vaporized and the main chain is cut. That is, this leads to lower molecular weight and lowers the original ability of the material.

  In coating and forming the light emitting layer 6 made of a polymer material by spin coating, in Example 1, MEH-PPV dissolved in toluene is used as the polymer organic electroluminescence material, and the film thickness is 120 nanometers. MEH-PPV is generally used as a polymer organic electroluminescence material, and can be purchased, for example, from Nippon Sebel Hegner. In addition to this, a styrene-based conjugated dendrimer or the like can be used as the polymer organic electroluminescent material.

  When the light emitting layer 6 is applied by the above-described spin coating method, the polymer organic electroluminescent material is applied on all the structures formed on the light emitting element substrate 70 before the light emitting layer 6 is formed. . In such a case, before forming the cathode 7 to be described later by vapor deposition, only a predetermined region is wiped off by a manufacturing facility that reapplies a solvent such as toluene or xylene and collects it together with the molten polymer organic electroluminescent material. . This wiping step can also be performed by, for example, a laser ablation method. Moreover, when the construction method which can apply | coat a polymeric organic electroluminescent material only to a predetermined area | region like the flood printing method using an inkjet technique is used, the above-mentioned wiping process becomes unnecessary.

  In any case, when a sealing portion 10 to be described later is formed in a state where a polymer organic electroluminescent material is applied to the entire surface of the light emitting element substrate 70, the organic electroluminescent element 1 (see FIG. 1)), it is confirmed that the shrinking of the light emitting portion LS (see FIG. 1) and the expansion of the dark spot easily proceed. The polymer organic electroluminescent material needs to be removed at least in the outer peripheral portion of the sealing portion 10.

  After this wiping process, the light emitting element substrate 70 is left in an environment of about 180 ° C. for about 1 hour to sufficiently volatilize an organic solvent such as toluene or xylene, which is a solvent in which the polymer organic electroluminescent material is dissolved (baking process). ). Hereinafter, the temperature in the baking process is referred to as the baking temperature.

  The light-emitting element substrate 70 according to the present invention includes a substrate 2, a plurality of light-emitting portions LS made of a polymer organic electroluminescent material formed on the substrate 2, and electrodes for supplying power to the light-emitting portions LS (later A cathode 7 to be described, and the cathode 7 is configured to cover the light emitting portion LS), and a sealing portion (sealing portion 10 to be described later) made of a thermosetting resin covering a range wider than at least the electrode. The use of a polymer organic electroluminescence material as a material of the light emitting layer 6 constituting the light emitting portion LS is a major point. Hereinafter, characteristics of the polymer organic electroluminescent material will be described in detail through comparison with the conventional low molecular organic electroluminescent material.

  Among the light-emitting materials that constitute organic electroluminescent elements, low-molecular organic electroluminescent materials that have been widely used in the past are generally vulnerable to high-temperature environments because their organic compound groups are formed by vacuum deposition into an amorphous thin film. It is known that its heat-resistant temperature is at most a few tens of degrees Celsius. This is because when exposed to a high temperature environment, the crystallization of the low molecular weight organic compound proceeds and the characteristics as a light emitting material deteriorate. In contrast, polymer organic electroluminescent materials form thin films by intertwining long molecular chains in a complicated manner, and there is no clear crystallization temperature, and there is an index that can be called the softening start temperature called the glass transition point. Just do it. Furthermore, even a clear glass transition point may not be observed in many polymer organic electroluminescent materials. In other words, the polymer organic electroluminescent material cannot move and crystallize freely due to the structure in which the molecules are intertwined. Such a characteristic of the polymer organic electroluminescent material appears as a great advantage of high heat resistance when the polymer organic electroluminescent material is applied to an organic electroluminescent element. This heat-resistant temperature sufficiently exceeds 200 ° C. including the already explained HEM-PPV. The light-emitting portion LS composed of the polymer organic electroluminescent material having the great feature of high heat resistance is not deteriorated in light-emitting characteristics even by sealing with a thermosetting resin described later, and is thermosetting. The high barrier property against moisture and gas of the resin can be effectively utilized.

  However, even low-molecular organic electroluminescent materials formed using a dry process such as vacuum deposition, oligomers with high molecular weight and relatively high glass point transfer, more specifically PPV oligomers, are exceptional. It has high heat resistance and can easily apply wet processes, and these can be applied to the light emitting element substrate 70 of the present invention as an alternative to the polymer organic electroluminescent material.

  In Example 1, the light emitting layer 6 is a single layer film made of MEH-PPV. However, it may be a laminated film made of several materials. For example, in order to confine the charge injected into the MEH-PPV layer and improve the recombination efficiency, it is desirable to add a layer made of a material having an electron blocking function or a hole blocking function, which leads to improvement in device characteristics. Specifically, the light-emitting layer 6 may have a three-layer structure of hole transport layer / electron blocking layer / the above-described organic light-emitting material (both not shown) in order from the anode 3 side. Two-layer structure of electron transport layer / organic light emitting material (both not shown) in order from the side, or two layer structure of hole transport layer / organic light emitting material (both not shown), or the anode 3 in order from the side of the anode 3 It is good also as a 7-layer structure (all not shown) like a hole injection layer / hole transport layer / electron block layer / organic light emitting layer / hole block layer / electron transport layer / electron injection layer in this order. As described above, the light emitting layer 6 in Example 1 includes a case where the light emitting layer 6 has a multilayer structure having functional layers such as a hole transport layer, an electron block layer, and an electron transport layer. The same applies to other embodiments described later.

The hole transport layer contained in the light emitting layer 6 is preferably a transparent material with high hole mobility and good film-forming properties. In addition to TPD described in the background art, porphin, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine , Porphyrin compounds such as titanium phthalocyanine oxide, 1,1-bis {4- (di-P-tolylamino) phenyl} cyclohexane, 4,4 ′, 4 ″ -trimethyltriphenylamine, N, N, N ′, N′-tetrakis (P-tolyl) -P-phenylenediamine, 1- (N, N-di-P-tolylamino) naphthalene, 4,4′-bis (dimethylamino) -2-2′-dimethyltriphenylmethane N, N, N ′, N′-tetraphenyl-4,4′-diaminobiphenyl, N, N′-diphenyl-N, N′-di-m-tolyl-4 Aromatic tertiary amines such as 4′-diaminobiphenyl and N-phenylcarbazole, 4-di-P-tolylaminostilbene, 4- (di-P-tolylamino) -4 ′-[4- ( Di-P-tolylamino) styryl] stilbene compounds, triazole derivatives, oxazizazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, annealed amine derivatives, Amino substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, polysilane aniline copolymers, polymer oligomers, styrylamine compounds, aromatic dimethylidins Compounds, Organic materials such as polythiophene derivatives such as poly-3,4 ethylene dioxythiophene (PEDOT), tetradihexylfluorenylbiphenyl (TFB), and poly-3-methylthiophene (PMeT) are used. Further, a polymer-dispersed hole transport layer in which an organic material for a low-molecular hole transport layer is dispersed in a polymer such as polycarbonate is also used. In addition, inorganic oxides such as MoO ₃ , V ₂ O ₅ , WO ₃ , TiO ₂ , SiO, and MgO may be used. These hole transport materials can also be used as an electron block material.

  As the electron transport layer in the light emitting layer 6 described above, oxadiazole derivatives such as 1,3-bis (4-tert-butylphenyl-1,3,4-oxadiazolyl) phenylene (OXD-7), anthraquinodimethane Derivatives, diphenylquinone derivatives, polymer materials composed of silole derivatives, etc., or bis (2-methyl-8-quinolinolate)-(para-phenylphenolate) Al (BAlq), bathofproin (BCP), etc. are used. Moreover, the material which can comprise these electron carrying layers can also be used as a hole block material.

  As mentioned above, although the light emitting layer 6 in Example 1 was demonstrated in detail, as a polymeric organic electroluminescent material which comprises the light emitting layer 6, it is not limited to the above-mentioned MEH-PPV, A fluorescence or phosphorescence characteristic in a visible region Can be selected, and polymer light-emitting materials such as polyparaphenylene vinylene (PPV) and polyfluorene can be used. Furthermore, polymer organic electroluminescent materials having various characteristics and emission colors have been proposed at present, and the light emitting layer 6 can be configured by appropriately selecting from these.

<Cathode>
Reference numeral 7 denotes a cathode in which a metal material such as Al is formed by, for example, a vacuum deposition method. As the cathode 7 of the organic electroluminescent element 1, a metal or alloy having a low work function, for example, a metal such as Al, In, Mg, Ti, or Ag, a Mg alloy such as a Mg—Ag alloy or a Mg—In alloy, Al— Al alloys such as a Li alloy, an Al—Sr alloy, and an Al—Ba alloy are used. Alternatively, a first electrode layer in contact with an organic material layer made of a metal such as Ba, Ca, Mg, Li, or Cs, or a fluoride or oxide of these metals such as LiF or CaO, and Al or Ag formed thereon. It is also possible to use a metal laminated structure including a second electrode made of a metal material such as In.

  The cathode 7 needs to cover at least the entire surface of the light emitting unit LS because of the need to supply charges to the light emitting unit LS. However, by covering the entire surface of the light emitting unit LS with the cathode 7 made of metal, the cathode 7 can be externally applied. It is also possible to have a sealing function for preventing the intrusion of moisture.

  In Example 1, the organic electroluminescence element is covered with the cathode 7 made of a metal having a high barrier property against gas and moisture, and further the entire cathode 7 is covered as will be described later, so that the barrier property is high. The light emitting device is constituted by a thermosetting resin.

  The organic electroluminescence element 1 is formed on the substrate 2 by the structure and process described above. The TFTs 102 are formed in a 1: 1 relationship with respect to the individual organic electroluminescence elements 1 and electrically constitute a so-called active matrix circuit. The source electrode 106 is used as a positive electrode, a predetermined potential difference is provided between the source electrode 106 and the cathode 7, and the gate electrode 104 is controlled to a predetermined potential, so that holes are generated in the source electrode 106, the TFT 102, the drain electrode 107, and the anode 3. Then, electrons are injected into the light emitting layer 6, while electrons are injected from the cathode 7 into the light emitting layer 6. In the light emitting layer 6, recombination of holes and electrons occurs, and a light emission phenomenon occurs when excitons generated thereby shift from the excited state to the ground state.

  Thus, the light-emitting device of Example 1 has an active matrix configuration, and the above-described cathode 7 is formed across the entire surface of the plurality of organic electroluminescence elements 1. When the passive matrix configuration is used, the cathodes need to be formed in stripes, resulting in steps caused by a large number of cathodes. However, when the active matrix configuration is used, the steps between the cathodes adversely affect the sealing performance. Never give. This is also one of the factors that improve the sealing performance.

  Light emitted from the light emitting layer 6 is transmitted through the anode 3, the intermediate layer 105, the gate insulating layer 103, the base coat layer 101, and the substrate 2, and is emitted from the surface opposite to the surface A of the substrate 2 to expose a not-shown photoreceptor. To do.

<Protection part>
Reference numeral 9 denotes a protective portion made of a material having a dense structure such as silicon oxide which is a metal oxide or silicon nitride which is a metal nitride. As will be described later in detail, the protection unit 9 is configured to cover at least the entire surface of the cathode 7. In Example 1, the protective part 9 is a film-like structure having a thickness of at least 50 nanometers, and is formed by, for example, sputtering. When the light-emitting element substrate 70 of Example 1 is applied to an exposure apparatus, the light-emitting element substrate 70 is not required to be flexible. Therefore, the protection unit 9 basically has a time restriction in the manufacturing process, for example, It is good to form it as thick as about 10 micrometers. By increasing the thickness of the protective part 9 in this way, the barrier property against moisture and gas is remarkably improved as a natural consequence. Furthermore, the level | step difference by the lower structure covered with the protection part 9 is absorbed reliably, and the surface of the protection part 9 will be in a uniform state without an unevenness | corrugation as a result. As a result, the adhesiveness with the sealing portion 10 described later becomes extremely stable, and the adhesive surface of the protective portion 9 and the sealing portion 10 can be brought into close contact, so that it is effective for moisture to enter through these gaps. Can be prevented. Further, since the surface of the protective part 9 is in a uniform state without unevenness, the adhesive strength at the outer peripheral part of the sealing part 10 becomes very strong, and the reliability can be improved against damage due to external force. It becomes possible. As an alternative to the above-described silicon oxide or silicon nitride, for example, silicon oxynitride may be used.

<Sealing part>
Reference numeral 10 denotes a sealing part made of a thermosetting resin, and the sealing part 10 completely covers the light emitting part LS whose size and shape are restricted by at least the pixel restricting part 8 as shown in the figure. As will be described in detail later with reference to FIG. 2, the sealing portion 10 further completely covers the cathode 7, and in the first embodiment, the outer peripheral portion thereof is bonded to the protective portion 9 described above.

  As the thermosetting resin, epoxy resin and acrylic resin are generally used. However, in Example 1, an epoxy resin is adopted in consideration of a small heat shrinkage and a small degassing. . In forming the sealing part 10 on the light emitting element substrate 70, a thermosetting resin is applied to the upper surface of the protective part 9 formed on the light emitting element substrate 70 using a dispenser. The sealing portion 10 can have a predetermined thickness by adjusting the supply amount of the thermosetting resin.

  The thickness required for the sealing part 10 is demonstrated below. The light-emitting element substrate 70 in Example 1 is assumed to be applied to an exposure apparatus mounted on a personal-use image forming apparatus, and the sealing portion 10 has a thickness of about 100 micrometers and exhibits sufficient sealing performance. To do. On the other hand, the thickness of the sealing part 10 should just be 50 micrometers or more if it is an application use with a comparatively few possibility of being left in a high humidity environment for a long time, such as a display use of a display apparatus. In addition, for an application application that is likely to be placed in a relatively high humidity environment such as an exposure apparatus applied to a so-called high-speed type image forming apparatus, the thickness of the sealing portion 10 may be about 200 micrometers. .

  The method for applying the thermosetting resin is not limited to the above-mentioned dispenser.

  Although the curing conditions vary depending on the thermosetting resin used, it is desirable that the first curing temperature is a heat treatment at 100 ° C. for about 1 hour, and then a heat treatment is performed at 150 ° C. for another hour. In order to relieve stress due to rapid heating, it is desirable to perform temperature-cure curing step by step.

  Normally, when the light emitting layer 6 of the organic electroluminescence element 1 is made of a low molecular material, when the sealing portion 10 is cured in a high temperature environment such as 100 ° C. or 150 ° C., the low molecular material constituting the light emitting layer 6 is crystallized. The light emitting function is lost. Furthermore, once crystallized, the molecular state is not restored even if the temperature is lowered. On the other hand, when the polymer material already described is used, the molecular state does not change even in such a high temperature environment, and the light emitting function is maintained.

  In Example 1, an epoxy resin was used as the thermosetting resin, but polycarbonate, polymethyl methacrylate, polyacrylate, methyl phthalate homopolymer or copolymer, polyethylene terephthalate, polystyrene, diethylene glycol bisallyl carbonate, acrylonitrile / Examples include styrene copolymers, poly (-4-methylpentene-1), phenol resins, cyanate resins, maleimide resins, polyimide resins, acrylic resins, and the like, and these include polyvinyl butyral, acrylonitrile-butadiene rubber, and polyfunctional acrylates. Uses modified with compounds, etc., and thermosetting resins modified with thermoplastic resins such as crosslinked polyethylene resin, crosslinked polyethylene / epoxy resin, polyphenylene ether / cyanate resin, etc. It is also possible. A plurality of types of resins as listed above may be used in combination. In addition, even if it is a photocurable resin, if a hardening accelerates | stimulates by heating, it can be used.

  Regarding the epoxy resin used as the sealing portion 10, there are two types, a photocurable resin and a thermosetting resin. In the former, a photoreactive crosslinking initiator is added, and the curing reaction is initiated by light, and then cured at a relatively low temperature, for example, 80 ° C. as a final treatment. In contrast, in the latter thermosetting resin, the curing reaction is also initiated by heat, and all curing is performed by heat. Therefore, the crosslinking density that governs the adhesiveness is higher for thermosetting resins than for photocurable resins. Get higher. This crosslink density is also closely related to the barrier property against moisture and gas, and the barrier property is improved as the crosslink density is increased.

  Further, the higher the glass transition temperature of the thermosetting resin, the higher the hardness of the resin after curing, so that the adhesive strength is reduced, which causes peeling from the substrate due to external or internal stress. Therefore, if the glass transition temperature of the resin is high, the sealing performance is not improved. On the other hand, a resin having a low glass transition temperature has a low adhesion strength inside the resin, resulting in a decrease in confidentiality. Considering these, it is desirable to select a resin having a glass transition temperature in the range of 140 ° C to 180 ° C.

  Further, an inorganic filler (filler) may be added to the resin itself in order to improve the moisture permeability of the resin. By adding an inorganic filler, it is possible to lengthen the infiltration path of moisture, gas, etc. that permeate the inside of the resin. Also, in order to suppress damage to the polymer organic electroluminescence as much as possible by degassing from the resin, it is desirable that there are few solvents and reaction initiators.

  The inorganic filler is preferably, for example, a plate-like inorganic filler or a scale-like inorganic filler. The plate-like inorganic filler and the scale-like inorganic filler are inorganic fillers having cleavage properties in most cases. Cleavage means that a crystal is easily cracked or peeled off in a certain direction and a smooth surface (cleavage surface) appears. That is, as a result, if it has cleavage property, each particle | grain of a filler will become plate shape or scale shape. Examples of such inorganic fillers include talc, mica, mica, and the like, but glass flakes are not particularly limited as long as the shape requirements are satisfied.

  The amount of these inorganic fillers added is also an important factor. In the thermosetting resin used in the present invention, the moisture permeability of the sealing portion 10 is remarkably increased by setting the content of the inorganic filler composed of the plate-like inorganic filler or the scaly inorganic filler to 20 weight percent or more. It can be reduced.

  Further, in order to improve the moisture permeability of the resin, an inorganic porous material so-called zeolite having fine pores on the surface thereof may be added to the resin itself as well as the inorganic filler. By adding the inorganic porous material, moisture, gas, and the like that permeate the inside of the resin are adsorbed by the micropores formed on the surface of the inorganic porous material and captured before reaching the light emitting portion. Furthermore, since the degassed component from the resin is also adsorbed, it is possible to suppress damage to the polymer organic electroluminescence.

  The inorganic porous material is preferably natural zeolite, synthetic zeolite, or silica gel, and activated carbon having a porous surface can also be used. Further, the diameter of the inorganic porous material is preferably about 5 micrometers or less, and if it becomes 10 micrometers or more, it will cause a short circuit of the polymer organic electroluminescence.

  Moreover, the addition amount of these inorganic porous materials is also an important factor similarly to the inorganic filler comprising a plate-like inorganic filler or a scale-like inorganic filler. In the thermosetting resin used in the present invention, the inorganic porous material has the same or more content of the inorganic filler composed of the plate-like inorganic filler or the flaky inorganic filler, so that the sealing portion 10 It is possible to significantly reduce the moisture permeability.

  As described in <Light-Emitting Layer>, the high-molecular organic electroluminescent material has a much higher heat-resistant temperature than the low-molecular organic electroluminescent material. Therefore, when the light emitting layer 6 is composed of a polymer organic electroluminescence material, the organic electroluminescence can be used even if a thermosetting resin having a water or gas barrier property that is remarkably superior to the photocurable resin is used as the sealing portion 10. The light emission characteristics of the element 1 are not deteriorated. The light emitting device substrate 70 of the present invention has a simple structure and a simple structure by sealing the organic electroluminescent device 1 composed of the polymer organic electroluminescent material having high heat resistance with a thermosetting resin. Despite being manufacturable in the process, high sealing performance can be obtained.

  The thermosetting resin constituting the sealing portion 10 has a final curing temperature set to 150 ° C., but as described in <Light emitting layer>, the light emitting layer 6 made of a polymer organic electroluminescent material. Is baked at 180 ° C. That is, in Example 1, a predetermined heat treatment (baking process) is performed in forming the light emitting portion LS, and the temperature at which the thermosetting resin is cured is controlled to be lower than the temperature of the predetermined heat treatment.

  In this way, by relaxing the temperature conditions necessary for processing as the manufacturing process becomes later, it is possible to minimize the factors that deteriorate the yield, for example, cracks occur in the light emitting layer 6 due to the thermal expansion of the structure. It becomes.

<Outer part of sealing part>
FIG. 2 is a cross-sectional view showing the configuration of the outer peripheral portion of the sealing portion 10 in the light emitting element substrate 70 of Example 1 of the present invention.

  Hereinafter, the configuration of the outer peripheral portion of the sealing portion 10 will be described in detail with reference to FIG.

  In FIG. 2, an arrow P indicates a structure constituting the light emitting element substrate 70 (that is, the substrate 2, the base coat layer 101, the gate insulating layer 103, the intermediate layer 105, the TFT protective layer 108, the pixel restricting portion 8, the light emitting layer 6, the cathode 7). The protection part 9 and the sealing part 10) are continuously formed from the arrow P in FIG. 1, and the same applies to the arrow Q. However, FIG. 1 and FIG. 2 are not immediately connected at the position of the arrow P or the arrow Q, but are connected through a small space (not shown). Further, in the case of the arrow Q, it is shown that a structure obtained by inverting FIG. 2 in the left-right direction of the drawing is continuously formed from the position of the arrow Q in FIG.

  As shown in FIG. 2, in Example 1, a protective portion 9 that covers at least the entire surface of the electrode (cathode 7) is formed between the electrode (cathode 7) and the sealing portion 10, and an outer peripheral portion of the sealing portion 10 is formed. It is configured to adhere to the protection unit 9.

  After the baking step described in <Light emitting layer>, the cathode 7 is formed so as to cover at least the entire surface of the light emitting portion LS (see FIG. 1) by vacuum deposition. The range in which the cathode 7 is formed can be adjusted with a relatively high degree of freedom by a mask in vacuum deposition. In Example 1, after the cathode 7 is formed, the protective portion 9 is formed so as to cover at least the entire surface of the cathode 7 and the pixel restricting portion 8. As already described, in the first embodiment, the pixel restricting portion 8 is formed of silicon oxide or silicon nitride. At this time, the protective portion 9 may be formed of the same material as that constituting the pixel restricting portion 8. desirable. That is, if the pixel restricting portion 8 is silicon oxide that is a metal oxide, it is desirable that the protective portion 9 is also made of silicon oxide. As a result, the coupling at the contact portion between the pixel restricting portion 8 and the protection portion 9 becomes stronger, and the effect of shielding the light emitting layer 6 and the cathode 7 sandwiched between them from the outside can be enhanced.

  After forming the protective part 9, the sealing part 10 is formed by the process described in <Sealing part>. At this time, the outer peripheral portion PO of the sealing portion 10 is bonded to the protective portion 9. As already described in <Sealing part>, the protective part 9 is made of a very dense material such as silicon oxide and can be formed sufficiently thick, so that the surface of the protective part 9 is a structure below it. Smoothness is extremely high without being affected by the unevenness of the film. As a result, the sealing part 10 formed on the protection part 9 is stably bonded to the protection part 9.

  Even if the protective part 9 and the sealing part 10 are firmly bonded in this way and the internal organic electroluminescent element 1 is sealed, an extremely small amount of water may enter the organic electroluminescent element 1. In order to suppress this as much as possible and ensure long-term reliability of the light emitting element substrate 70, the end of the light emitting layer 6 and the sealing portion 10 are wiped off (see the description of <light emitting layer> for the wiping process). It is necessary to secure the outermost peripheral distance Lf (sealing margin) as long as possible. The sealing margin Lf is required to be at least 0.5 mm or more, and if it is 2 mm, sufficient sealing performance can be ensured.

  In general, in the structure related to the TFT 102 (see FIG. 1) constituting the light emitting element substrate 70, an interface for inputting a control signal to drive the TFT 102 is configured in the peripheral portion of the TFT protective layer 108. Specifically, a contact hole (not shown) for making contact with an external circuit is formed in the periphery of the TFT protective layer 108, but the contact hole and the external wiring (not shown) connected to the contact hole are uneven. Therefore, if the sealing part 10 covers the contact part even if the range of the sealing part 10 is simply expanded in order to secure the sealing margin Lf, moisture or gas is conversely formed by the unevenness of the lower part. There is a possibility that the barrier property against the above may be impaired.

  FIG. 3 is a cross-sectional view of the light emitting element substrate 70 according to the first embodiment of the present invention when the sealing portion 10 is enlarged to a contact hole with an external circuit and an external wiring region.

  Hereinafter, a configuration in the case where the sealing portion 10 is expanded to a contact hole with an external circuit and an external wiring region will be described with reference to FIG. In FIG. 3, the light emitting layer 6 and the cathode 7 shown in FIG. 2 are not shown, but this is because the sealing margin Lf indicating the distance between the end of the light emitting layer 6 and the outermost periphery of the sealing portion 10 is sufficiently large. This is because the light emitting layer 6 and the cathode 7 do not exist in the region shown in FIG.

  In FIG. 3, reference numeral 119 denotes a wiring pattern provided on the gate insulating layer 103. 110 is a contact hole provided as an opening in the TFT protective layer 108 for connection to an external circuit (not shown), and 120 is connected to the contact hole 110 to connect the wiring pattern 119 and the external circuit (not shown). External wiring. In FIG. 3, only one contact hole 110 and one external wiring 120 are shown. However, in the actual light emitting element substrate 70, a plurality of these are provided in a direction perpendicular to the paper surface. Therefore, the surface of the TFT protective layer 108 has unevenness due to the presence or absence of the external wiring 120.

  In Example 1, the light emitting element substrate 70 has at least a wiring part (external wiring 120) for inputting a control signal related to driving of the light emitting part LS (see FIG. 1), and the protection part 9 covers the external wiring 120. In addition, the sealing unit 10 is configured to adhere to the protection unit 9.

  The external wiring 120 formed on the TFT protective layer 108 is based on ITO, and has a multilayer structure in which a metal layer such as molybdenum is provided thereon to reduce wiring resistance. Can be formed. The thickness of the external wiring thus formed is about 150 to 200 nanometers. As already described in <Sealing part>, the protective part 9 can be formed to a sufficient thickness, for example, several tens of micrometers. Therefore, the unevenness formed by the external wiring 120 having a thickness of about 200 nanometers at most is formed by the protective part 9. The area in which the contact hole 110 and the external wiring 120 exist is almost completely filled, and as a result, the protective portion 9 forms a uniform surface without unevenness. Further, since a dry process such as a sputtering method is employed for forming the protective part 9, the metal oxide and metal nitride constituting the protective part 9 are buried very densely in the irregularities formed by the external wiring 120, and between them. There is no gap that impedes barrier properties against moisture and gas.

  In Example 1, since at least the outer peripheral portion of the sealing portion 10 is adhered on the protective portion 9 formed in this manner, the sealing portion 10 is adhered to the protective portion 9 very stably.

  As shown in FIG. 2, when the protection unit 9 is configured not to reach the region where the external wiring 120 is formed, a metal may be used as the protection unit 9 instead of the metal oxide or metal nitride described above. Good. In this way, since the TFT 102 (see FIG. 1) and the entire wiring region are covered with metal (and the potential is the same as that of the cathode 7 and can be GND), external noise and the like are blocked. Thus, malfunction of the TFT 102 (see FIG. 1) can be reduced. However, in this case, since the wiring pattern 119 and the protection unit 9 are very close to each other, the operation speed of the TFT 102 (see FIG. 1) may be restricted by the capacitance. With respect to this problem, if the thickness of the intermediate layer 105 and the TFT protective layer 108 is increased, it is possible to achieve both noise resistance and delay due to capacitance.

  On the other hand, as shown in FIG. 3, when the protective portion 9 is configured to extend to the region where the external wiring 120 is formed, the protective portion 9 is required to have insulation, and therefore metal is used as the material constituting the protective portion 9. However, the metal oxides and metal nitrides already described are used.

<Overall structure of light-emitting element substrate>
4A is a top view of the light-emitting element substrate 70 according to the first embodiment of the present invention, and FIG. 4B is an enlarged view of the main part thereof. Hereinafter, the configuration of the light-emitting element substrate 70 in Example 1 will be described in detail with reference to FIG.

  In FIG. 4, a light emitting element substrate 70 is a rectangular substrate having a thickness of about 0.7 millimeters and having at least a long side and a short side. A plurality of organic light emitting elements are arranged in the long side direction (main scanning direction). The electroluminescence elements 1 are formed in a row. As described above, the light emitting portion (not shown) of the organic electroluminescence element 1 is made of a polymer organic electroluminescence material. In the first embodiment, light emitting elements necessary for at least A4 size (210 millimeter) exposure are arranged in the long side direction of the light emitting element substrate 70, and the long side direction of the light emitting element substrate 70 is an arrangement space of a drive control unit 78 described later. Including 250 mm. In the first embodiment, the light emitting element substrate 70 is described as a rectangle for the sake of simplicity. However, the positioning of the light emitting element substrate 70 is not limited for the purpose of positioning when the light emitting element substrate 70 is attached to a housing A74a of an exposure apparatus described later. It may be accompanied by such a deformation that a part is notched.

  A drive control unit 78 receives a control signal (a signal for driving the organic electroluminescence element 1) supplied from the outside of the light emitting element substrate 70, and controls the driving of the organic electroluminescence element 1 based on the control signal. And includes an interface means (FPC 80) for receiving a control signal from the outside of the light emitting element substrate 70 and an IC chip (source driver 81) for controlling the driving of the light emitting element based on the control signal received through the interface means, as will be described later. It is out.

  Reference numeral 80 denotes an FPC (flexible printed circuit) as an interface means for connecting the connector A 73a (see FIG. 5) of the relay substrate 72 and the light emitting element substrate 70, and is not shown provided on the light emitting element substrate 70 without using a connector or the like. Connected directly to the circuit pattern. As described above, the image data, the light amount correction data, the control signal such as the clock signal and the line synchronization signal, the driving power source of the control circuit, and the organic electroluminescence which is the light emitting element are supplied to the exposure apparatus 33 (see FIG. 5) from the outside. The drive power for the luminescence element 1 is supplied to the light emitting element substrate 70 via the FPC 80 after passing through the relay substrate 72 (see FIG. 5) once.

  In Example 1, 5120 organic electroluminescence elements 1 as light sources of an exposure apparatus to be described later are formed in a row at a resolution of 600 dpi in the longitudinal direction of the light emitting element substrate 70 (main scanning direction). The electroluminescence elements 1 are independently controlled to be turned on / off by a TFT circuit described later.

  A source driver 81 is supplied as an IC chip for controlling the driving of the organic electroluminescence element 1 and is flip-chip mounted on the light emitting element substrate 70. Considering that surface mounting is performed on the glass surface, the source driver 81 employs a bare chip product. The source driver 81 is supplied with control-related signals such as a power supply, a clock signal, and a line synchronization signal, and light amount correction data (for example, 8-bit multi-value data) from the outside of the exposure apparatus 33 via the FPC 80. As will be described in detail later, the source driver 81 is a drive parameter setting unit for the organic electroluminescence element 1. More specifically, the source driver 81 is based on the light amount correction data passed through the FPC 80. This is for setting the drive current value.

  In the light emitting element substrate 70, the joint portion of the FPC 80 and the source driver 81 are connected through, for example, an ITO circuit pattern (not shown) having a metal formed on the surface, and the FPC 80 is connected to the source driver 81 as drive parameter setting means. Control signals such as light quantity correction data, a clock signal, and a line synchronization signal are input via the. Thus, the FPC 80 as the interface means and the source driver 81 as the drive parameter setting means constitute the drive control unit 78.

  Reference numeral 108 denotes the TFT protective layer already described, and a TFT (Thin Film Transistor) circuit (not shown) is formed under the surface of the TFT protective layer 108. The TFT circuit includes a shift controller, a data latch unit, and the like, a gate controller that controls the timing of turning on / off the light emitting elements, and a driving circuit that supplies a driving current to each organic electroluminescence element 1 (hereinafter referred to as a pixel circuit). Is included. One pixel circuit is provided for each organic electroluminescence element 1 and is arranged in parallel with the light emitting element row formed by the organic electroluminescence element 1. As will be described later in detail, a drive current value for driving each organic electroluminescence element 1 is set in the pixel circuit by a source driver 81 as drive parameter setting means.

  A TFT circuit (not shown) is supplied with a control signal such as a power supply, a clock signal, and a line synchronization signal and image data (1-bit binary data) from the outside of the exposure apparatus (not shown) via the FPC 80. The TFT circuit (not shown) controls the lighting / extinguishing timing of each light emitting element based on these power supplies and signals.

  As already described, reference numeral 9 denotes a protective part formed on the TFT protective layer 108, and the sealing part 10 is provided on the protective part 9. A contact hole 110 is formed in the TFT protective layer 108, and an external wiring 120 is connected to the contact hole 110. In FIG. 4, for easy explanation, the organic electroluminescence element 1, the contact hole 110, and the external wiring 120 are drawn so as to be visible, but these are actually covered with the protective part 9 and the sealing part 10, so It cannot be visually observed. FIG. 4 shows a case where the protective portion 9 is configured to cover all of the contact holes 110 and a part of the external wiring 120, and corresponds to the configuration described with reference to FIG.

  In the first embodiment, as shown in FIG. 4, a contact hole 110 is provided as an opening in the TFT protective layer 108 and is connected to the source driver 81 via the external wiring 120 made of ITO + metal. The contact hole 110 is opened at a position corresponding to a signal terminal (bump part) of the source driver 81 which is an IC chip (bare chip), and extended to the arrangement area of the driver 81, and the source driver 81 is directly joined thereto. It may be configured. In this way, the external wiring 120 can be simultaneously formed in the process of creating the TFT circuit, and the manufacturing process of the light emitting element substrate 70 can be simplified. Similarly, a wiring between the junction portion of the FPC 80 and the source driver 81 can also be provided under the TFT protective layer 108.

  Reference numeral 77 denotes a light quantity sensor unit in which a plurality of light quantity sensors made of amorphous silicon or the like are arranged along the light emitting element substrate 70 in the main scanning direction. The amount of light emitted from each organic electroluminescence element 1 is measured by the light amount sensor unit 77. The output of the light amount sensor unit 77 is once taken into a TFT circuit (not shown) by a wiring (not shown), subjected to signal processing such as amplification and analog-digital conversion, and then output to the outside of the light emitting element substrate 70 via the FPC 80. .

  This signal is received and processed by a controller 61 (see FIG. 5), which will be described later, to generate light amount correction data (for example, 8 bits), and the light emission amounts of all the organic electroluminescence elements 1 are controlled to be substantially equal. .

  In the first embodiment, the FPC 80 serving as the interface means constituting the drive control unit 78 and the source driver 81 serving as the drive parameter setting means in the light emitting element substrate 70 are on the extension line of the light emitting element row formed by the organic electroluminescence element 1 (EL_dir). It was made to provide in the position.

  With such an arrangement, the drive control unit 78 is arranged at a position that does not overlap the light emitting element array at an arbitrary position in the long side direction (main scanning direction) of the light emitting element substrate 70. At the same time, in this configuration, at an arbitrary position in the long side direction (main scanning direction) of the light emitting element substrate 70, the drive control unit 78 is positioned so as not to overlap with a TFT circuit (not shown) formed in parallel with the light emitting element array. Will be placed. Further, the sealing unit 10 does not use a bathtub-shaped glass plate or the like as in the prior art, and only a necessary region of the light emitting element substrate 70 is used for sealing. Due to this synergistic effect, the size of the light emitting element substrate 70, particularly the size in the sub-scanning direction, can be reduced. In general, when a TFT circuit is configured on a glass substrate or the like, the number of substrates obtained from a mother glass of a predetermined size has the most influence on the cost as well as simplification of the manufacturing process. Therefore, by reducing the size of the light emitting element substrate 70, the manufacturing cost of the light emitting element substrate 70 can be dramatically reduced.

<Lighting control of organic electroluminescence element and size of light emitting element substrate>
FIG. 5 is a circuit diagram relating to the light emitting element substrate 70 of Example 1 of the present invention. Hereinafter, the lighting control by the TFT circuit and the source driver 81 will be described in more detail with reference to FIG.

  In FIG. 5, reference numeral 82 denotes a TFT circuit configured on the light emitting element substrate 70. Reference numeral 61 denotes a controller incorporated in the image forming apparatus, which receives image data from a computer (not shown) or the like and generates printable image data, and as described above, the light amount sensor unit 77 disposed on the light emitting element substrate 70. Light amount correction data is generated based on the output (see FIG. 4).

  An image memory 85 stores binary image data generated by the controller 61 based on a command transferred from a computer (not shown). A light amount correction data memory 86 stores light amount correction data. The light quantity correction data memory 86 is a rewritable nonvolatile memory such as an EEPROM. In the manufacturing process of the exposure apparatus 33, the light emission amount and the light emission luminance distribution of all the organic electroluminescence elements 1 are measured for each exposure apparatus 33, and the light emission of each organic electroluminescence element 1 is based on these measurement results. A step of generating light amount correction data for making the light amounts substantially equal is included, and the light amount correction data memory 86 stores the value of the light amount correction data.

  The controller 61 can update the light amount correction data to light amount correction data newly generated based on the output of the light amount sensor unit 77 (see FIG. 4).

  A timing generation unit 87 generates a control signal related to timing for driving the organic electroluminescence element 1 formed on the light emitting element substrate 70. The image data stored in the image memory 85 and the light amount correction data stored in the light amount correction data memory 86 (or copied in advance to another high-speed memory not shown) are the clock signal and line generated by the timing generation unit 87. Based on the synchronization signal and the like, the light is supplied to the light emitting element substrate 70 through the cable 76, the connector B 73b, the relay substrate 72, the connector A 73a, and the FPC 80 which will be described later with reference to FIG.

  Further, the image data and the timing signal supplied to the light emitting element substrate 70 are supplied to the TFT circuit 82 by a wiring formed on the light emitting element substrate 70, for example, a metal layer on ITO, and the light amount correction data and timing are supplied. Similarly, the signal is supplied to the source driver 81.

  The TFT circuit 82 is roughly divided into a pixel circuit 89 and a gate controller 88. One pixel circuit 89 is provided for each organic electroluminescent element 1, and N groups are provided on the light emitting element substrate 70 with the M pixels of the organic electroluminescent element 1 as one group. In the first embodiment, one group is 8 pixels (that is, M = 8), and this group is 640. Therefore, the total number of pixels is 8 × 640 = 5120 pixels. Each pixel circuit 89 supplies a current to the organic electroluminescent element 1 to drive the driver unit 90, and a current value supplied by the driver to control the lighting of the organic electroluminescent element 1 (that is, a driving current value of the organic electroluminescent element 1) ) Is stored in a capacitor included therein, and the organic electroluminescence element 1 can be driven at a constant current according to a drive current value programmed in advance at a predetermined timing.

  The gate controller 88 includes a shift register that sequentially shifts input binary image data, and a latch unit that is provided in parallel with the shift register and collectively holds the input after a predetermined number of pixels are input to the shift register. The control unit controls these operation timings (both not shown). Further, the gate controller 88 outputs SCAN_A and SCAN_B signals, thereby controlling the timing of turning on / off the organic electroluminescent element 1 connected to the pixel circuit 89 and the timing of the current program period for setting the drive current.

  On the other hand, the source driver 81 has a number of D / A converters 92 (640 in the first embodiment) corresponding to the number N of groups of the organic electroluminescence elements 1 inside, and the source driver 81 is supplied via the FPC 80. Based on the light amount correction data (for example, 8 bits), the drive current for each organic electroluminescence element 1 is set to control the light emission luminance of each organic electroluminescence element 1 to be substantially equal.

  Next, the size of the light emitting element substrate 70 will be described with reference to FIGS. 4 and 2 in FIG.

  Now, in the exposure apparatus equipped with the light emitting element substrate 70, when an exposure range of A4 size (about 210 millimeters) is obtained with a resolution of 600 dpi in the main scanning direction, as described above, 5120 organic electroluminescence elements 1 are used. However, the scale of the TFT circuit 82 for driving these pixels is about 500,000 gates according to the study by the present inventors. When this is formed with a process rule of 4.5 micrometers, the shift register, latch part, and other control system circuits included in the gate controller 88 are about 1000 micrometers wide and the pixel circuit 89 is 200 micrometers wide. Is required in the sub-scanning direction. The wiring from the source driver 81 to the pixel circuit 89 can be suppressed to 1500 micrometers by multilayering the routing in the intermediate layer 105 (see FIG. 1) where the TFT circuit 82 is formed, for example. Then, the width of the TFT circuit in the sub-scanning direction can be set to about 2700 micrometers. That is, the TFT circuit 82 is formed with a width of 2700 micrometers in the direction from the organic electroluminescence element 1 to the contact hole 110 in FIG.

  As described with reference to FIG. 2, in the light emitting element substrate 70 of Example 1, the sealing margin Lf is 2000 micrometers and exhibits a sufficient sealing performance. Therefore, as shown in FIG. 4, if the sealing margin Lf in the direction from the organic electroluminescence element 1 to the light quantity sensor unit 77 is also 2000 micrometers, the width in the sub-scanning direction where either the TFT circuit 82 or the sealing margin Lf exists is present. Is about 4700 micrometers. If the area of the external wiring 120 shown in FIG. 4 is added to this, the size of the light emitting element substrate 70 in the sub-scanning direction can be realized with about 5 millimeters.

  On the other hand, the width of the source driver 81 in the sub-scanning direction can be suppressed to about 3000 micrometers when the 640 D / A converters 92 are mounted (the width in the main scanning direction is about 16000 micrometers). As already described, since the source driver 81 is mounted on the light emitting element substrate 70 at a position on the extended line of the light emitting element row, the width of the source driver 81 restricts the size of the light emitting element substrate 70 in the sub-scanning direction. Absent.

  As described above, the light emitting element substrate 70 of Example 1 has a very small size in the sub-scanning direction, the size of the exposure apparatus is reduced as described later, and the size of the image forming apparatus can be further reduced.

<Exposure device>
FIG. 6 is a block diagram of an exposure apparatus on which the light emitting element substrate 70 according to the first embodiment of the present invention is mounted. Hereinafter, the structure of the exposure apparatus will be described in detail with reference to FIG.

  In FIG. 6, reference numeral 33 denotes an exposure apparatus mounted on the image forming apparatus, on which the light emitting element substrate 70 already described is mounted. On the light emitting element substrate 70, a light emitting element, that is, an organic electroluminescence element 1 (see FIG. 1) as an exposure light source is formed at a resolution of 600 dpi (dot per inch) in a direction (main scanning direction) perpendicular to the drawing.

  Reference numeral 71 denotes a lens array in which rod lenses (not shown) made of plastic or glass are arranged in a row, and the light emitted from the organic electroluminescence element 1 formed on the light emitting element substrate 70 is erecting at an equal magnification. As an image, it is guided to the surface of the photoreceptor 28 where a latent image is formed. One focal point of the lens array 71 is the surface A of the substrate 2 constituting the light emitting element substrate 70, and the other focal point of the light emitting element substrate 70, the lens array 71, and the photosensitive member 28 is the surface of the photosensitive member 28. The positional relationship has been adjusted. That is, when the distance L1 from the surface A of the substrate 2 to the surface closer to the lens array 71 and the distance L2 from the other surface of the lens array 71 to the surface of the photoreceptor 28 are set, L1 = L2. Is done.

  Reference numeral 72 denotes a relay substrate using a glass epoxy substrate, for example. 73a is a connector A, 73b is a connector B, and at least a connector A73a and a connector B73b are mounted on the relay board 72. The relay substrate 72 temporarily relays image data, light amount correction data, and other control signals supplied from the outside to the exposure apparatus 33 via a cable 76 such as a flexible flat cable, etc., via a connector B 73b, and these signals are light emitting elements. Passed to the substrate 70.

  Since it is difficult to directly mount a connector on the surface of the substrate 2 constituting the light emitting element substrate 70 in consideration of bonding strength and reliability in various environments where the exposure apparatus 33 is placed, the relay substrate 72 is used in the first embodiment. FPC (flexible printed circuit) is employed as a connection means between the connector A73a and the light emitting element substrate 70 (not shown), and the light emitting element substrate 70 and FPC are joined using, for example, an ACF (anisotropic conductive film). For example, an ITO (indium tin oxide) electrode formed on the light emitting element substrate 70 in advance is directly connected.

  On the other hand, the connector B73b is a connector for connecting the exposure apparatus 33 to the outside. In general, connection by ACF or the like often has a problem of bonding strength, but by providing the connector B73b for connecting the exposure apparatus 33 on the relay substrate 72 in this way, the interface directly accessed by the user is provided. Sufficient strength can be ensured.

  Reference numeral 74a denotes a casing A which is formed by bending a metal plate, for example. An L-shaped portion 75 is formed on the side of the housing A 74 a facing the photoreceptor 28, and the light emitting element substrate 70 and the lens array 71 are disposed along the L-shaped portion 75. The L-shaped portion 75 is molded by aligning the end surface of the housing A74a on the photosensitive member 28 side with the end surface of the lens array 71 and further supporting one end of the light emitting element substrate 70 by the housing A74a. If the accuracy is ensured, the positional relationship between the light emitting element substrate 70 and the lens array 71 can be accurately adjusted. As described above, since the casing A 74a is required to have dimensional accuracy, the casing A 74a is preferably made of metal. Further, by making the casing A74a made of metal, the influence of noise on electronic components such as a control circuit using a TFT formed on the light emitting element substrate 70 and an IC chip surface-mounted on the light emitting element substrate 70 is reduced. It is possible to suppress.

  74b is a casing B obtained by molding a resin. A notch (not shown) is provided in the vicinity of the connector B73b of the housing B74b, and the user can access the connector B73b from this notch. Via the cable 76 connected to the connector B73b, the image data, the light amount correction data, the control signal such as the clock signal and the line synchronization signal, the driving power source of the control circuit, and the organic light emitting element are supplied from the outside of the exposure device 33 to the exposure device 33. Drive power for the electroluminescence element is supplied.

  Now, as already explained in <Lighting control of organic electroluminescence element and size of light emitting element substrate>, the width of the light emitting element substrate 70 (see FIG. 4) of Example 1 in the sub-scanning direction may be about 5 mm. Therefore, the thickness Z of the exposure apparatus 33 on which the light emitting element substrate 70 is mounted can be reduced to 7 mm or less by making the thickness of the casing A 74a and the casing B 74b less than 1 mm.

<Configuration of image forming apparatus>
FIG. 7 is a configuration diagram of an image forming apparatus equipped with an exposure device 33 to which the light emitting element substrate 70 of Example 1 of the present invention is applied.

  In FIG. 7, the image forming apparatus 21 arranges development stations for four colors, a yellow developing station 22Y, a magenta developing station 22M, a cyan developing station 22C, and a black developing station 22K, in a vertical direction in a stepwise manner. A paper feed tray 24 that accommodates the recording paper 23 is disposed, and a recording paper transport path 25 that serves as a transport path for the recording paper 23 supplied from the paper feed tray 24 is provided at locations corresponding to the developing stations 22Y to 22K. Are arranged in the vertical direction from above to below.

  The developing stations 22Y to 22K form yellow, magenta, cyan, and black toner images in order from the upstream side of the recording paper conveyance path 25. The yellow developing station 22Y includes a photoconductor 28Y and a magenta developing station 22M. The photosensitive member 28M and the cyan developing station 22C include the photosensitive member 28C, the black developing station 22K includes the photosensitive member 28K, and each developing station 22Y to 22K includes a series of electrophotographic systems such as a developing sleeve and a charger (not shown). The member which implement | achieves the image development process in is included.

  Further, exposure devices 33Y, 33M, 33C, and 33K for exposing the surfaces of the photoreceptors 28Y to 28K to form electrostatic latent images are disposed below the developing stations 22Y to 22K.

  The developing stations 22Y to 22K are different in the color of the filled developer, but the configuration is the same regardless of the developing color. Therefore, the developing stations are excluded unless particularly necessary to simplify the following description. 22, the photosensitive member 28, and the exposure device 33 will be described without specifying specific colors.

  FIG. 8 is a configuration diagram illustrating the periphery of the developing station 22 in the image forming apparatus 21 according to the first exemplary embodiment of the present invention. In FIG. 8, the developing station 22 is filled with a developer 26 which is a mixture of carrier and toner. Reference numerals 27a and 27b denote stirring paddles for stirring the developer 26. The toner in the developer 26 is charged to a predetermined potential by friction with the carrier by the rotation of the stirring paddles 27a and 27b, and the interior of the developing station 22 is also charged. By circulating, the toner and the carrier are sufficiently stirred and mixed. The photoreceptor 28 is rotated in the direction D3 by a driving source (not shown). A charger 29 charges the surface of the photoreceptor 28 to a predetermined potential. 30 is a developing sleeve, and 31 is a thinning blade. The developing sleeve 30 has a magnet roll 32 having a plurality of magnetic poles formed therein. The layer thickness of the developer 26 supplied to the surface of the developing sleeve 30 is regulated by the thinning blade 31 and the developing sleeve 30 is rotated in the direction D4 by a driving source (not shown). As a result, the developer 26 is supplied to the surface of the developing sleeve 30, and an electrostatic latent image formed on the photoconductor 28 is developed by an exposure device described later, and the developer 26 not transferred to the photoconductor 28 is developed. It is collected inside the station 22.

  Reference numeral 33 denotes the exposure apparatus already described. As already described, the light emitting element substrate 70 (see FIG. 4) mounted on the exposure apparatus 33 has an excellent sealing performance and can form a latent image stably over a long period of time, so that the product life as an exposure apparatus is increased. Since a long electrostatic latent image having a desired shape can be obtained over a long period of time, a high-quality image can always be formed.

  As described above, the exposure apparatus 33 according to the first embodiment includes the organic electroluminescence elements 1 arranged linearly at a resolution of 600 dpi (dot per inch), and is a photosensitive member charged to a predetermined potential by the charger 29. On the other hand, by selectively turning on / off the organic electroluminescence element according to the image data, an electrostatic latent image having a maximum A4 size is formed. Only the toner of the developer 26 supplied to the surface of the developing sleeve 30 adheres to the electrostatic latent image portion, and the electrostatic latent image is visualized.

  A transfer roller 36 is provided at a position facing the recording paper conveyance path 25 with respect to the photoreceptor 28, and is rotated in the direction D5 by a driving source (not shown). A predetermined transfer bias is applied to the transfer roller 36, and the toner image formed on the photoconductor 28 is transferred to the recording paper 23 conveyed through the recording paper conveyance path 25.

  Hereinafter, the description will be continued returning to FIG.

  As described above, the image forming apparatus 21 according to the first exemplary embodiment is a tandem type color image forming apparatus in which a plurality of developing stations 22Y to 22K are arranged in a stepwise manner in the vertical direction, and is equivalent to a color inkjet printer. It aims at size. Since a plurality of units are arranged in the developing stations 22Y to 22K, in order to reduce the size of the image forming apparatus 21, the developing stations 22Y to 22K themselves are reduced in size and are arranged around the developing stations 22Y to 22K. It is necessary to reduce the members involved in the image process and to reduce the arrangement pitch of the developing stations 22Y to 22K as much as possible.

  In consideration of user convenience when installing the image forming apparatus 21 on the desktop in an office or the like, in particular, accessibility to the recording paper 23 at the time of paper feed or paper discharge, from the bottom surface of the image forming apparatus 21 to the paper feed port 65. The height is preferably 250 mm or less. In order to realize this, it is necessary to suppress the height of the entire developing stations 22Y to 22K to about 100 millimeters in the entire configuration of the image forming apparatus 21. However, the existing LED head, for example, has a thickness of about 15 millimeters, and if it is disposed between the developing stations 22Y to 22K, it is difficult to achieve the target. According to the examination results of the present inventors, when the thickness of the exposure device 33 is 7 millimeters or less, the height of the entire development station is 100 millimeters even if the exposure devices 33Y to 33K are arranged in the gaps between the development stations 22Y to 22K. The following can be suppressed. As described in <Exposure apparatus>, since the thickness Z of the exposure apparatus 33 of Embodiment 1 is less than 7 millimeters, the height of the entire developing station is set to 100 millimeters or less, and a very small image forming apparatus 21 is configured. It becomes possible.

  A toner bottle 37 stores yellow, magenta, cyan, and black toners. A toner transport pipe (not shown) is provided from the toner bottle 37 to each of the developing stations 22Y to 22K, and supplies toner to each of the developing stations 22Y to 22K.

  A paper feed roller 38 is rotated in the direction D1 by controlling an electromagnetic clutch (not shown), and feeds the recording paper 23 loaded in the paper feeding tray 24 to the recording paper transport path 25.

  A registration paper 39 and a pair of pinch rollers 40 are provided as a nip conveyance means on the inlet side in the recording paper conveyance path 25 positioned between the paper supply roller 38 and the transfer portion of the most upstream yellow developing station 22Y. The registration roller 39 and the pinch roller 40 pair temporarily stop the recording paper 23 conveyed by the paper supply roller 38 and convey it in the direction of the yellow developing station 22Y at a predetermined timing. This temporary stop restricts the leading edge of the recording paper 23 in parallel with the axial direction of the registration roller 39 and pinch roller 40 pair, thereby preventing the recording paper 23 from skewing.

  Reference numeral 41 denotes a recording paper passage detection sensor. The recording paper passage detection sensor 41 is constituted by a reflective sensor (photo reflector), and detects the leading edge and the trailing edge of the recording paper 23 based on the presence or absence of reflected light.

  When the rotation of the registration roller 39 is started (the power transmission is controlled by an electromagnetic clutch (not shown) and the rotation is turned ON / OFF), the recording paper 23 is conveyed along the recording paper conveyance path 25 in the direction of the yellow developing station 22Y. However, starting from the rotation start timing of the registration roller 39, the writing timing of the electrostatic latent images by the exposure devices 33Y to 33K disposed in the vicinity of the developing stations 22Y to 22K is independently controlled.

  A fixing device 43 is provided as a nip conveying means on the outlet side in the recording paper conveyance path 25 located further downstream of the most downstream black developing station 22K. The fixing device 43 includes a heating roller 44 and a pressure roller 45. The heating roller 44 is a multi-layered roller composed of a heating belt, a rubber roller, and a core material (both not shown) in order from the surface. Among them, the heat generating belt is a belt having a three-layer structure, and is composed of a release layer, a silicon rubber layer, and a base material layer (both not shown) from the side closer to the surface. The release layer is made of a fluororesin having a thickness of about 20 to 30 micrometers and imparts release properties to the heating roller 44. The silicon rubber layer is made of silicon rubber having a thickness of about 170 micrometers and gives the pressure roller 45 appropriate elasticity. The base material layer is made of a magnetic material that is an alloy of iron, nickel, chromium, or the like.

  A back core 46 includes an exciting coil. Inside the back core 46, an excitation coil in which a predetermined number of copper wires (not shown) whose surfaces are insulated is bundled in the direction of the rotation axis of the heating roller 44, and at both ends of the heating roller 44, the heating roller It circulates along the circumferential direction of 44. When an alternating current of about 30 kHz is applied to the exciting coil from an exciting circuit (not shown) that is a semi-resonant inverter, a magnetic flux is generated in a magnetic path constituted by the back core 46 and the base layer of the heating roller 44. Due to this magnetic flux, an eddy current is formed in the base material layer of the heat generating belt of the heating roller 44 and the base material layer generates heat. The heat generated in the base material layer is transmitted to the release layer through the silicon rubber layer, and the surface of the heating roller 44 generates heat.

  Reference numeral 47 denotes a temperature sensor for detecting the temperature of the heating roller 44. The temperature sensor 47 is a ceramic semiconductor obtained by sintering at a high temperature using a metal oxide as a main raw material, and it is possible to measure the temperature of a contacted object by applying a change in load resistance according to the temperature. it can. The output of the temperature sensor 47 is input to a control device (not shown). The control device controls the power output to the exciting coil inside the back core 46 based on the output of the temperature sensor 47, and the surface temperature of the heating roller 44 is about 170 ° C. Control to be

  When the recording paper 23 on which the toner image is formed is passed through the nip formed by the heating roller 44 and the pressure roller 45 that are controlled in temperature, the toner image on the recording paper 23 is connected to the heating roller 44. The toner image is fixed on the recording paper 23 by being heated and pressurized by the pressure roller 45.

  A recording paper trailing edge detection sensor 48 monitors the discharge state of the recording paper 23. Reference numeral 52 denotes a toner image detection sensor. The toner image detection sensor 52 is a reflective sensor unit that uses a plurality of light emitting elements (both visible light) having different emission spectra and a single light receiving element, and changes the image color between the background of the recording paper 23 and the image forming portion. Accordingly, the image density is detected by utilizing the fact that the absorption spectrum is different. Further, since the toner image detection sensor 52 can detect not only the image density but also the image forming position, the image forming apparatus 21 according to the first exemplary embodiment is provided with two toner image detection sensors 52 in the width direction of the image forming apparatus 21, and recording paper. The image formation timing is controlled based on the detection position of the image position deviation amount detection pattern formed on the image 23.

  53 is a recording paper transport drum. The recording paper transport drum 53 is a metal roller whose surface is covered with rubber having a thickness of about 200 micrometers, and the recording paper 23 after fixing is transported along the recording paper transport drum 53 in the direction D2. At this time, the recording sheet 23 is cooled by the recording sheet conveying drum 53 and is bent and conveyed in the direction opposite to the image forming surface. As a result, curling that occurs when a high density image is formed on the entire surface of the recording paper can be greatly reduced. Thereafter, the recording paper 23 is conveyed in the direction D6 by the kicking roller 55 and discharged to the paper discharge tray 59.

  Reference numeral 54 denotes a face-down paper discharge unit. The face-down paper discharge unit 54 is configured to be rotatable about the support member 56. When the face-down paper discharge unit 54 is opened, the recording paper 23 is discharged in the direction D7. In the closed state, the face-down paper discharge unit 54 is formed with ribs 57 along the transport path on the back surface so as to guide the transport of the recording paper 23 together with the recording paper transport drum 53.

  Reference numeral 58 denotes a drive source. In the first embodiment, a stepping motor is employed. By the drive source 58, peripheral portions of the developing stations 22Y to 22K including the paper feed roller 38, the registration roller 39, the pinch roller 40, the photoconductors (28Y to 28K), and the transfer rollers (36Y to 36K), the fixing device 43, The recording paper transport drum 53 and the kicking roller 55 are driven.

  Reference numeral 61 denotes a controller that receives image data from a computer (not shown) via an external network, and develops and generates printable image data.

  Reference numeral 62 denotes an engine control unit. The engine control unit 62 controls the hardware and mechanism of the image forming apparatus 21, forms a color image on the recording paper 23 based on the image data transferred from the controller 61, and performs overall control of the image forming apparatus 21. Yes.

  63 is a power supply unit. The power supply unit 63 supplies power of a predetermined voltage to the exposure apparatuses 33Y to 33K, the drive source 58, the controller 61, and the engine control unit 62, and supplies power to the heating roller 44 of the fixing device 43. The power supply unit also includes a so-called high-voltage power supply system such as charging of the surface of the photoconductor 28, a developing bias applied to the developing sleeve (see reference numeral 30 in FIG. 8), and a transfer bias applied to the transfer roller 36.

  The power supply unit 63 includes a power supply monitoring unit 64 so that at least the power supply voltage supplied to the engine control unit 62 can be monitored. This monitor signal is detected by the engine control unit 62 to detect a decrease in power supply voltage that occurs when the power switch is turned off or a power failure occurs.

  In the above description, the case where the present invention is applied to a color image forming apparatus has been described. However, the present invention can also be applied to a single color image forming apparatus such as black. When applied to a color image forming apparatus, the development colors are not limited to four colors of yellow, magenta, cyan and black.

(Example 2)
FIG. 9 is a cross-sectional view showing the configuration of the light-emitting element substrate 70 in Example 2 of the present invention.

  Hereinafter, the configuration of the light-emitting element substrate 70 of Example 2 will be described with reference to FIG. In addition, about the light emitting element substrate 70 demonstrated in Example 2, the exposure apparatus which applied this light emitting element substrate 70, and the image forming apparatus carrying this exposure apparatus, description is abbreviate | omitted about Example 1 and a common part.

  FIG. 9 is a drawing corresponding to FIG. 2 in the description of the first embodiment. In the first embodiment (FIG. 2), the cathode 7 is configured to cover a part of the pixel restricting portion 8. However, in the second embodiment (FIG. 9), the cathode 7 covers a wider area than the pixel restricting portion 8. 7 is in contact with the TFT protective layer 108.

  The configuration of the light-emitting element substrate 70 in Example 2 also includes the substrate 2 and a plurality of light-emitting portions made of a polymer organic electroluminescent material formed on the substrate 2 (the light-emitting portion LS already described, see FIG. 1), It has an electrode 7 covering this light emitting part LS and a sealing part 10 made of a thermosetting resin covering at least a wider area than this electrode, and its operational effects are almost the same as those described in the first embodiment. However, the second embodiment is different from the first embodiment in that the pixel restricting portion 8 is made of a resin such as polyimide.

  When a resin such as polyimide is used as the pixel restricting portion 8, after forming the TFT protective layer 108 on the substrate 2, an insulating material of, for example, about 1 μm made of photosensitive polyimide is spin coated to form the light emitting element substrate 70. It is applied to the entire surface and patterned into a predetermined shape by a photolithography method to form the pixel restricting portion 8. When a water repellent material such as polyimide is used as the pixel restricting portion 8, the surface roughness Ra is roughened to about 5 nanometers after the formation of the pixel restricting portion 8 by ultraviolet irradiation treatment or plasma treatment, and the polymer organic It is desirable to process so that it may have high wettability with respect to the solvent which melt | dissolves electroluminescent material, such as toluene and xylene, or the solution which melt | dissolved high molecular organic electroluminescent material. By doing so, the coating unevenness of the polymer organic electroluminescent material applied by a spin coating method or the like is reduced, and as a result, the light emission luminance distribution in the light emitting portion LS of the organic electroluminescent element 1 (see FIG. 1) is reduced. It is made uniform.

  In addition to the polyimide described above, the pixel restricting portion 8 includes a vinyl group, water-absorbing silicon, isocyanate, polyester polymer, polyamide, fluorine-containing polymer, epoxy group as the main chain, or a vinyl group, glycidyl group, aryl group, etc. at the end. A held polymer material can also be used.

  Now, after the pixel restricting portion 8 is formed, as described in <Light-Emitting Layer>, the polymer organic electroluminescent material is applied to the light-emitting element substrate 70, and unnecessary areas are wiped off. The cathode 7 is formed according to the materials and methods described. Since resin materials such as polyimide generally transmit a slight amount of moisture, when using a resin as the pixel regulating portion 8, the pixel regulating portion 8 is completely covered with the cathode 7 made of a metal material such as Al. The barrier property against moisture and gas can be improved.

(Example 3)
FIG. 10 is a cross-sectional view showing the configuration of the light-emitting element substrate 70 in Example 3 of the present invention.

  Hereinafter, the configuration of the light-emitting element substrate 70 of Example 3 will be described with reference to FIG. In addition, about the light emitting element substrate 70 demonstrated in Example 3, the exposure apparatus which applied this light emitting element substrate 70, and the image forming apparatus carrying this exposure apparatus, description is abbreviate | omitted about Example 1 and a common part.

  FIG. 10 is a drawing corresponding to FIG. 2 in the description of the first embodiment. As shown in the drawing, the light emitting element substrate 70 in Example 3 includes a substrate 2 and a plurality of light emitting portions made of a polymer organic electroluminescence material formed on the substrate 2 (the light emitting portion LS already described, see FIG. 1), It has an electrode (cathode 7) covering this light emitting part LS and a sealing part 10 made of a thermosetting resin covering at least a wider area than this electrode (cathode 7), and further sealed with the electrode 7 (cathode 7). A protective portion 9 that covers at least a wider area than the electrode (cathode 7) is formed between the portions 10, and a sealing portion 10 made of a thermosetting resin is configured to cover a wider area than the protective portion 9. is there.

  At this time, the peripheral portion of the sealing portion 10 is bonded to the TFT protective layer 108. As described in <TFT>, the TFT protective layer 108 is a dense film such as silicon nitride, and is formed to a thickness of at least about 300 nanometers. ing. As a result, the peripheral portion of the sealing portion 10 can be bonded to the TFT protective layer 108 without a gap.

  In the third embodiment, reference numeral 9 denotes a protective part made of a hygroscopic material such as aluminum oxide or calcium oxide. The protective part 9 is a film-like structure having a thickness of at least 50 nanometers and can be formed by, for example, a sputtering method.

  The protective part 9 is preferably configured to cover not only the light emitting part LS of the organic electroluminescence element 1 (see FIG. 1) but also the entire surface of the cathode 7.

  Since the protective part 9 made of a hygroscopic material is completely covered with the sealing part 10 made of a thermosetting resin, the protective part 9 is not directly exposed to the atmosphere. Since the amount of moisture penetrating the sealing portion 10 is extremely small, the protective portion 9 can exhibit a hygroscopic action even when the thickness is about 50 nanometers.

  When the light-emitting element substrate 70 of the present invention is applied to an exposure apparatus, the light-emitting element substrate 70 is not required to be flexible. Therefore, the protection unit 9 basically has, for example, several numbers as long as time constraints in the manufacturing process allow. You may form thickly about 10 micrometers. By increasing the thickness of the protective part 9 in this way, the step due to the lower structure covered by the protective part 9 is reliably absorbed, and as a result, the surface of the protective part 9 is in a uniform state without unevenness. At the same time, it is possible to achieve a very advantageous state in which the hygroscopic material can be increased.

  It is of course possible to form the protective part 9 in a multilayer of the above-described hygroscopic material and the metal oxide or metal nitride described in the first embodiment. In this case, the barrier property against moisture and gas can be further improved by providing a structure in which the layer of the hygroscopic material is completely covered with the metal oxide or metal nitride layer.

Example 4
FIG. 11 is a cross-sectional view showing a configuration of a light emitting element substrate 70 in Example 4 of the present invention.

  Hereinafter, the configuration of the light-emitting element substrate 70 of Example 4 will be described with reference to FIG. In addition, about the light emitting element substrate 70 demonstrated in Example 4, the exposure apparatus which applied this light emitting element substrate 70, and the image forming apparatus carrying this exposure apparatus, description is abbreviate | omitted about Example 1 and a common part.

  FIG. 11 is a drawing corresponding to FIG. 2 in the description of the first embodiment. As shown in the drawing, the light emitting element substrate 70 in Example 4 includes a substrate 2 and a plurality of light emitting portions made of a polymer organic electroluminescence material formed on the substrate 2 (the light emitting portion LS already described, see FIG. 1), It has an electrode (cathode 7) covering this light emitting part LS and a sealing part 10 made of a thermosetting resin covering at least a wider area than this electrode (cathode 7), and further the light emission of the light emitting part LS on the substrate 2 The pixel restricting portion 8 for restricting the region is provided, and the outer peripheral portion of the sealing portion 10 made of a thermosetting resin is bonded to the pixel restricting portion 8.

  In the fourth embodiment, reference numeral 8 denotes a pixel restricting portion that restricts the position, shape, size, and the like of the light emitting portion LS that contributes to light emission by covering a part of the anode 3, and the pixel restricting portion 8 is already a <pixel restricting portion>. As described in detail, it is a film-like structure formed of silicon nitride or silicon oxide having a thickness of 50 nanometers to 2 micrometers. As shown in the figure, the pixel restricting portion 8 is formed on the TFT protective layer 108, but the TFT protective layer 108 is also made of a dense material such as silicon nitride or silicon oxide as described in <TFT>. , Having a thickness of about 300 nanometers. In this manner, by providing the pixel restricting portion 8 having a dense structure on the TFT protective layer 108 in the same manner, the surface of the pixel restricting portion 8 can be made uniform with no unevenness. Therefore, the sealing portion 10 made of a thermosetting resin formed on the pixel restricting portion 8 is in close contact with the pixel restricting portion 8 without any gap, and the barrier property against moisture and gas can be maintained extremely high.

  In the fourth embodiment, silicon nitride or silicon oxide is used as the pixel restricting portion 8, but a resin material such as polyimide as shown in the second embodiment may be used as the pixel restricting portion 8. However, in this case, in order to ensure sealing performance, it is desirable that the pixel restricting portion 8 is completely covered with the sealing portion 10.

  The light-emitting device of the present invention and the exposure apparatus and image forming apparatus using the same reliably protect the organic electroluminescence element from moisture and gas in the external atmosphere despite the simple structure, and generate shrinking and dark spots. In addition, it is possible to effectively prevent enlargement, so that it can be used in various apparatuses that need to obtain stable light emission over a long period of time, and can be applied to, for example, a copying machine, a multifunction printer, a printer, and a facsimile machine. . In addition, since organic electroluminescent elements can obtain the three primary colors of red, green, and blue by selecting an organic light emitting material, for example, if an exposure device that exposes each color of RGB is used, an image of a type that directly exposes photographic paper. It can also be applied to a forming apparatus. In addition, the light emitting device of the present invention is not only applicable to an exposure apparatus and an image forming apparatus, but is formed of a light emitting element such as an organic electroluminescence element and needs to be sealed, such as a display. The present invention can also be applied to a display device.

Sectional drawing which shows the structure of the organic electroluminescent element in the light emitting element substrate of Example 1 of this invention. Sectional drawing which shows the structure of the outer peripheral part of the sealing part in the light emitting element substrate of Example 1 of this invention. Sectional drawing at the time of enlarging to the area | region of the contact hole with an external circuit, and the external wiring in the light emitting element substrate of Example 1 of this invention (A) Top view of the light emitting element substrate of Example 1 of the present invention, (b) Enlarged view of the main part. 1 is a circuit diagram relating to a light-emitting element substrate of Example 1 of the present invention. 1 is a configuration diagram of an exposure apparatus equipped with a light-emitting element substrate in Example 1 of the present invention. 1 is a configuration diagram of an image forming apparatus equipped with an exposure apparatus to which a light emitting element substrate according to Embodiment 1 of the present invention is applied. 1 is a configuration diagram showing the periphery of a developing station in an image forming apparatus according to Embodiment 1 of the present invention. Sectional drawing which shows the structure of the light emitting element substrate in Example 2 of this invention. Sectional drawing which shows the structure of the light emitting element substrate in Example 3 of this invention. Sectional drawing which shows the structure of the light emitting element substrate in Example 4 of this invention. Sectional drawing which shows the structure of the conventional organic electroluminescent element

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic electroluminescent element 2 Board | substrate 3 Anode 6 Light emitting layer 7 Cathode 8 Pixel control part 9 Protection part 10 Sealing part 11 Organic electroluminescent element 12 Glass substrate 13 Anode 14 Hole transport layer 15 Organic material layer 16 Light emitting layer 17 Cathode 18 Sealing unit 21 Image forming device 22, 22Y, 22M, 22C, 22K Development station 23 Recording paper 25 Recording paper transport path 28, 28Y, 28M, 28C, 28K Photosensitive member 33, 33Y, 33M, 33C, 33K Exposure device 61 Controller 62 Engine control unit 70 Light emitting element substrate 71 Lens array 78 Drive control unit 80 FPC
81 source driver 82 TFT circuit 85 image memory 86 light quantity correction data memory 87 timing generation unit 88 gate controller 89 pixel circuit 101 base coat layer 102 TFT
103 Gate insulating layer 105 Intermediate layer 108 TFT protective layer 110 Contact hole 119 Wiring pattern 120 External wiring

Claims (21)

Consists of a substrate, a plurality of light emitting portions formed on the substrate using a polymer organic electroluminescent material, an electrode for supplying power to the light emitting portion, and a thermosetting resin covering at least a wider area than the electrodes And a sealed portion. The protective part which covers at least the whole surface of the said electrode is formed between the said electrode and the said sealing part, and it comprised so that the outer peripheral part of the said sealing part might adhere | attach the said protective part. Light-emitting device. A wiring unit for inputting at least a control signal for driving the light emitting unit is provided on the substrate, the protection unit is configured to cover the wiring unit, and the sealing unit is bonded to the protection unit. The light emitting device according to claim 2, wherein the light emitting device is configured as follows. The light emitting device according to claim 2, further comprising: a pixel restricting portion that restricts a light emitting region of the light emitting portion on the substrate, wherein the pixel restricting portion and the protection portion are made of the same material. The light emitting device according to claim 4, wherein the protection unit and the pixel regulation unit are made of metal oxide or metal nitride. 2. A protection part that covers at least a range wider than the electrode is formed between the electrode and the sealing part, and the sealing part is configured to cover a range wider than the protection part. The light-emitting device of description. The light emitting device according to claim 6, wherein the protection part is made of a hygroscopic material. 2. The light emitting device according to claim 1, further comprising: a pixel restricting portion that restricts a light emitting region of the light emitting portion on the substrate, wherein an outer peripheral portion of the sealing portion is bonded to the pixel restricting portion. apparatus. The light emitting device according to claim 1, wherein the sealing portion is made of an epoxy resin having a glass transition temperature of 140 ° C. to 180 ° C. The light emitting device according to claim 1, wherein the sealing portion is configured to contain an inorganic filler having a cleavage property. The light-emitting device according to claim 1, wherein a driving circuit including a TFT for driving the light-emitting portion is provided on the substrate, and the driving circuit is covered with the sealing portion. The light emitting device according to claim 1, wherein the sealing portion is configured to contain an inorganic porous material (zeolite) having water absorption. The light emitting device according to claim 1, wherein the sealing portion is configured so that the filling amount of the inorganic porous material having water absorption is equal to or greater than the filling amount of the inorganic filler having cleavage property. The light emitting device according to claim 1, 2, 6, 12, or 13, wherein the sealing portion is configured to have a thickness of 50 micrometers or more. 15. An exposure apparatus comprising the light-emitting device according to claim 1, wherein the plurality of light-emitting units can be turned on / off independently. 16. The exposure apparatus according to claim 15, wherein the light emitting unit is driven by an active matrix circuit provided on the substrate. A step of forming a plurality of light emitting portions on the substrate using a polymer organic electroluminescent material, a step of forming an electrode covering the light emitting portion, and at least a range wider than the electrodes made of a thermosetting resin. The manufacturing method of the light-emitting device characterized by having the sealing process sealed with a stop part. 18. The light emitting device according to claim 17, further comprising a step of removing the organic electroluminescent material at a position corresponding to at least an outer peripheral portion of the sealing portion after applying a polymer organic electroluminescent material on the substrate. Device manufacturing method. 18. A step of performing a heat treatment after applying a polymer organic electroluminescent material on the substrate, wherein the temperature of the heat treatment is set higher than a temperature for later curing the thermosetting resin. The manufacturing method of the light-emitting device of description. 18. The method of manufacturing a light emitting device according to claim 17, wherein, in the sealing step, at least two stages of curing temperatures are provided, and the curing temperature is set higher as the later curing temperature. 17. The exposure apparatus according to claim 15, a photosensitive member on which a latent image is formed by the exposure apparatus, and a developing station that develops and visualizes the latent image formed on the photosensitive member. And an image forming apparatus comprising: a transfer unit that transfers the image developed by the developing station to a recording sheet; and a fixing unit that fixes the image transferred by the transfer unit.

Images