JP5862164B2 - Electrophoretic display device and method of manufacturing electrophoretic display device - Google Patents

Description

  The present invention relates to a microcapsule type electrophoretic display device, and an electrophoretic display layer comprising a microcapsule in which a color filter layer and a charged pigment are encapsulated on a transparent electrode layer on a transparent substrate of a light guide plate. The present invention relates to a microcapsule type electrophoretic display device having a structure that enables bright display and is visible in a dark environment, and a method for manufacturing the same.

  In recent years, with the development of information equipment, information display has been made in various forms. As the variable information display, a CRT (cathode ray tube), a liquid crystal display, and the like are mainly used. A light-emitting display such as a liquid crystal display of the type using a CRT or a backlight is not suitable for reading a document or the like because it makes the eyes look tired when used for a long time.

  As flat panel display devices, liquid crystal displays are thin and can be miniaturized, so they are currently widely used in various applications. However, a light-emitting display such as a transmissive LCD has a problem that the eyes are easily fatigued and the optical characteristics greatly vary depending on the viewing angle.

  On the other hand, a liquid crystal display of a type that does not use a backlight has a problem that the darkness of the screen due to the use of a polarizing plate appears and the visibility is poor. Furthermore, the images displayed on these displays have no memory property and have the disadvantage that they disappear as soon as the electrical energy supply is stopped.

  In the display display of portable information devices such as e-books and portable information terminals that are expected to become more widespread in the future, even when used for a long time, it is less likely to cause eye fatigue, good visibility, low power consumption, In addition, it is considered necessary to have image memory properties.

  Among them, electronic paper is one of display devices that are particularly attracting attention. This has the advantages of both paper and an electronic display, and has the feature that image information is retained even in a non-powered state and can be rewritten. In addition, since electronic paper has a reflective display, the contrast ratio does not change and the viewing angle is wide. For example, an electronic paper electrophoretic display device using microcapsules as in Patent Document 1 has been proposed.

JP 2000-221546 A

  However, although electronic paper can be visually recognized by reflecting light from the outside such as sunlight and fluorescent lamps, there is a problem that it cannot be displayed at night or in a dark environment. In addition, it is difficult for the electronic paper to have a transmission type like a liquid crystal display and to transmit light from the back surface of the backlight.

  On the other hand, in recent years, a multicolor display has been demanded and is being actively developed. In the multicolor display, a method for performing multicolor display by attaching a color filter on an electrophoretic display device for monochrome display of two colors has been announced. In this method, for example, an electrophoretic display layer, a transparent electrode layer, and a transparent substrate are laminated on a pixel electrode substrate through an adhesive layer, and another transparent substrate on which a color filter layer is formed is bonded through the adhesive layer. . Furthermore, it takes the structure which bonded the protective film on the transparent substrate on the opposite side to the color filter layer via the adhesive layer.

  However, in the above method, it is necessary to newly provide an adhesive layer between the color filter layer and the electrophoretic display layer, and a distance is increased between the color filter layer and the electrophoretic display layer. The advantage of electronic paper, which has a wide viewing angle, is lost. Furthermore, there is a problem that the light utilization efficiency is lowered and the display brightness is further lowered when the external light passes through the constituent members such as the transparent substrate and the color filter layer.

  The present invention has been made to solve the above-described problem, and in a microcapsule type electrophoretic display device capable of multicolor display, a structure in which a light source, a light guide plate, an electrophoretic display layer, and a color filter layer are integrated. By providing a front light consisting of a light source and a light guide plate that has a structure that uniformly emits light taken in from the light source into the plane, it becomes possible to perform bright display with high light utilization efficiency, Prevents the narrowing of the viewing angle caused by overlaying color filters on the microcapsule type electrophoretic display device, prevents the brightness from being reduced by the passage of external light through the components, and can be used in night and dark environments. An object of the present invention is to provide a microcapsule electrophoretic display device integrated with a light source having a structure capable of visually recognizing display contents and a method for manufacturing the same. .

In order to achieve the above-mentioned object in the present invention, in claim 1, a light source and light which is introduced into the inside of the light irradiated from the light source and propagates inside the light is one surface in the thickness direction. a transparent light guide plate to emit from the emission surface, wherein the transparent light guide plate the light exit plane to the undercoat layer a color filter layer formed over the, on a surface thereof opposite to the undercoat layer of the color filter layer Formed overcoat layer, transparent electrode layer formed on the surface of the overcoat layer opposite to the color filter layer, formed on the surface of the transparent electrode layer opposite to the overcoat layer , back electrode made of an electrophoretic display layer containing capsules, the electrophoretic display layer the formed via a conductive adhesive layer on the surface opposite to the transparent electrode layer, the pixel electrode and the rear substrate And a plate, the other surface in the thickness direction of the transparent light guide plate which is opposite to the surface and the light exit plane, inclined at a constant upward slope along the propagation direction of light within said transparent light guide plate A second inclined surface that is inclined with a downward gradient greater than the upward gradient along the light introduction direction from the ridge line that is the uppermost end of the first inclined surface to the transparent light guide plate. Convex ridges formed of inclined surfaces and reflecting part of the light introduced into the transparent light guide plate in the light exit surface direction are continuously formed along the other surface, and the transparent light guide plate The undercoat layer and the overcoat layer are formed to reduce the difference between the refractive index of the undercoat layer and the refractive index of the undercoat layer, and the difference between the refractive index of the undercoat layer and the refractive index of the overcoat layer. An adjusting agent for adjusting the refractive index is added to the material to be There is provided an electrophoretic display device characterized by being.

In claim 2, the difference between the refractive index of the transparent light guide plate and the refractive index of the undercoat layer, and the difference between the refractive index of the undercoat layer and the refractive index of the overcoat layer are 0.2, respectively. The electrophoretic display device according to claim 1, wherein the electrophoretic display device is as follows.

In claim 3, wherein the electrophoretic display layer includes a first color of the electrophoretic particles positively charged, microcapsules and the second electrophoretic particles are contained in a liquid dispersion medium negatively charged there is provided an electrophoretic display device according to claim 1 or 2 wherein, characterized in that it contains.

In claim 4, under the light exit surface of the transparent light guide plate to emit from the light exit surface which is one surface in the thickness direction of light propagating inside by introducing the light irradiated to the inside from the light source coating Forming a color filter layer after coating the layer, forming an overcoat layer on the surface of the color filter layer opposite to the undercoat layer, and the side of the overcoat layer opposite to the color filter layer forming a transparent electrode layer on the surface of, and forming an electrophoretic display layer containing microcapsules on a surface thereof opposite to the overcoat layer of the transparent electrode layer, the transparent of the electrophoretic display layer And applying a conductive adhesive layer to the surface opposite to the electrode layer, and then forming a back electrode substrate comprising a pixel electrode and a back substrate, the transparent surface being the surface opposite to the light emitting surface. On the other surface in the thickness direction of the light guide plate, there are a first inclined surface inclined at a constant upward gradient along the light propagation direction inside the transparent light guide plate, and an uppermost end of the first inclined surface. A second inclined surface inclined at a descending gradient greater than the ascending gradient along a direction in which the light is introduced from a certain ridge line to the transparent light guiding plate, and the light introduced into the transparent light guiding plate A step of continuously forming a ridge portion reflecting a part in the light exit surface direction along the other surface, a difference between a refractive index of the transparent light guide plate and a refractive index of the undercoat layer, and Adding a regulator for adjusting the refractive index in the material for forming the undercoat layer and the overcoat layer in order to reduce the difference between the refractive index of the undercoat layer and the refractive index of the overcoat layer; electrophoretic, characterized by further comprising There is provided a method of manufacturing shown apparatus.

In claim 5, the difference between the refractive index of the difference between the refractive index of the refractive index of the transparent light guide plate and the undercoat layer, and the overcoat layer and the refractive index of the undercoat layer is, respectively 0.2 The method for manufacturing an electrophoretic display device according to claim 4 , wherein:

  According to the present invention, in order to solve the above problems, the light source, the light guide plate, the electrophoretic display layer, and the color filter layer are integrated, and the front light transparent light guide plate is also used as a substrate. By illuminating the display surface from the front side, the display brightness can be prevented from being lowered, and the display contents can be visually recognized even in a dark environment.

  In addition, by forming the electrophoretic display layer directly on the transparent light guide plate provided with the transparent electrode layer, the electrophoretic display layer and the color filter layer are close to each other. This also has the effect of preventing the narrowing of the viewing angle.

It is sectional drawing of the electrophoretic display device 1 of this invention. It is a mimetic diagram of a microcapsule contained in a microcapsule display layer concerning an embodiment of the present invention.

  The best mode for carrying out the present invention will be specifically described below with reference to the drawings.

  One of display devices using electrophoresis is an electrophoretic display device using microcapsules. In a microcapsule filled with a dispersion medium, white particles and colored particles that are positively and negatively charged are placed, and an image is formed by pulling up each particle to the display surface by applying an external voltage. Since the size of the microcapsules is as small as several tens of μm to several hundreds of μm, when the microcapsules are dispersed in a transparent binder material, they can be coated like ink.

  An active matrix display can be obtained by coating the ink on a transparent resin film on which a transparent electrode is formed and bonding the ink to a substrate on which an electrode circuit for driving an active matrix represented by a TFT is formed. Usually, a component in which a transparent resin film on which a transparent electrode is formed is coated with electronic ink is called a “front plate”, and a substrate on which an electrode circuit for driving an active matrix is formed is called a “back plate”. In addition to the active matrix, various substrates and films having conductivity can be used for the back plate.

FIG. 1 is a schematic view showing an example of an electrophoretic display device 1 of the present invention.
As shown in FIG. 1, the front light unit 5 of the electrophoretic display device 1 of the present invention is provided with a transparent light guide plate 4 (first substrate) made of a transparent substrate and a light source 2 as constituent members. The light source 2 is provided on the end side of the transparent light guide plate 4. The transparent light guide plate 4 includes a light guide structure that introduces light emitted from the light source 2 into the inside and emits light propagating through the inside to a surface on the color filter layer 10 side described later.

  The electrophoretic display device 1 further includes a color filter layer 10, an overcoat layer 11, and a transparent electrode layer in which color inks 9 (9a, 9b, and 9c) corresponding to red, green, and blue are provided on the undercoat layer 8. 12, an electrophoretic display layer 15, a conductive adhesive 16, a back electrode substrate 19 (second substrate) including a pixel electrode 17 and a back substrate 18. As will be described in detail later, the electrophoretic display layer 15 includes a microcapsule 13 and a binder resin 14 that contain white particles 19 and colored particles 20.

In other words, the electrophoretic display device 1 includes a light source 2 and a first substrate (transparent light guide plate 4) that includes a transparent substrate that introduces light emitted from the light source 2 into the interior and emits light propagating through the interior from an exit surface. A second substrate (back electrode substrate 19) disposed at a position opposite to the first substrate and having electrodes, a color filter layer 10 formed between the first substrate and the second substrate, and a color filter layer 10 An overcoat layer 11 formed in contact with the overcoat layer 11, a transparent electrode layer 12 formed in contact with the overcoat layer 11, an electrophoretic display layer 15 formed in contact with the transparent electrode layer 12 and containing microcapsules, An electrophoretic display layer 15 and an adhesive layer 16 formed in contact with the second substrate.

A color filter layer 10 is formed by applying an undercoat layer 8 to the light exit surface 7 side of the transparent light guide plate 4 by a predetermined coating method and applying a color ink 9 on the undercoat layer 8. Yes. That is, the color filter layer 10 is formed by laminating the color ink 9 on the undercoat layer 8 provided on the first substrate.

  An overcoat layer 11 is formed so as to cover the color filter layer 10, and a transparent electrode layer 12 is formed on the surface of the overcoat layer 11. Next, the electrophoretic display layer 15 is formed by applying a coating liquid in which the microcapsules 13 and the binder resin 14 are dispersed on the transparent electrode layer 12 by a predetermined coating method.

  Further, a conductive adhesive 16 is applied on a conductive release substrate having a silicon layer as a release layer on the conductive layer and the surface layer to form a conductive adhesive substrate, and the electrophoretic display layer 15 and the conductive adhesive are bonded. The agent 16 side is bonded together.

  Next, the electrophoretic display device 1 of the present invention is obtained by bonding the surface of the conductive adhesive 16 and the surface of the pixel electrode 17 of the back electrode substrate 19 including the pixel electrode 17 and the back substrate 18.

That is, the electrophoretic display device 1 of the present invention has the color filter layer 10 on the first substrate made of a transparent substrate that introduces light emitted from the light source 2 into the interior and emits light propagating through the light exit surface. Forming the overcoat layer 11 in contact with the color filter layer 10, forming the transparent electrode layer 12 in contact with the overcoat layer 11, and the electrophoretic display layer 15 containing microcapsules. Forming an adhesive layer in contact with the transparent electrode layer 12, forming an adhesive layer in contact with the electrophoretic display layer 15, and a second electrode having an electrode at an opposing position of the first substrate through the adhesive layer. And a step of installing a substrate.

The transparent light guide plate 4 is formed so that the wedge shape is continuous, and preferably has a structure in which one of the wedge shapes has a steep slope and the other has a gentler inclination angle than the slope. This is because a part of the light introduced into the transparent light guide plate 4 through the light incident surface is reflected by the structure in the direction of the light emission surface, so that the light orthogonal to the light emission surface is the light. uniformly emitted from the light emission face, the strength of the whole of light emitted from the light exit plane to electrophoresis dynamic display layer 15 is to increase. The configuration and shape of the slope are not limited to those described above, and any configuration and shape may be used as long as the light guide plate has a structure that exhibits the above effects. Further, the substrate of the transparent light guide plate 4 functions as a support for the light incident from the light source 2 to illuminate the display surface and to hold the color filter layer 10 and the electrophoretic display layer 15. Various transparent substrates, such as resin, an acrylic resin, and a polyethylene terephthalate resin, can be mentioned.

  Although the thickness of the transparent light guide plate 4 is not limited, a material having flexibility that allows the transparent light guide plate 4 to withstand continuous processing with bending is suitable. It becomes possible to manufacture, and it leads to a significant manufacturing cost reduction.

  The undercoat layer 8 is formed by a predetermined coating method such as die coating, bar coating, spin coating, screen printing, or offset printing using urethane resin, acrylic resin, polyester resin, vinyl chloride meter resin, or the like. To do.

  As a method for forming the color ink layer 9 of the color filter layer 10, various printing methods such as ink jet printing, screen printing, and offset printing can be used.

The material of the overcoat layer 11 formed to have flatness need not be limited to a specific resin, but may be an organic resin such as polyamide, polyimide, polyurethane, polycarbonate, acrylic resin, silicon, or Si ₃ N _4. , SiO ₂ , Al ₂ O ₃ , Ta ₂ O ₃ and other inorganic films can be formed by spin coating, die coating, bar coating, roll coating, various printing methods, or vapor deposition.

  Further, it is desirable that the difference in the refractive index of light incident from the light source 2 in each of the transparent light guide plate 4, the undercoat layer 8, and the overcoat layer 11 is close to zero. Specifically, the difference between the refractive index of the transparent light guide plate 4 (light guide structure) and the refractive index of the undercoat layer 8 and the difference between the refractive index of the undercoat layer 8 and the refractive index of the overcoat layer 11 are: Each should be 0.2 or less. This can suppress the reflection of light at the interface between the transparent light guide plate 4 and the undercoat layer 8 and the interface between the undercoat layer 8 and the overcoat layer 11, and the reflected light reaches the eyes of the observer. This is because it can be suppressed.

  Further, adjustment for adjusting the refractive index in the material forming the undercoat layer 8 and the overcoat layer 11 in order to reduce the difference from the refractive index of the transparent light guide plate 4, the undercoat layer 8 and the overcoat layer 11. An agent can also be added. As the additive, for example, materials such as zirconium oxide and titanium oxide are suitable.

  The thickness of the overcoat layer 11 is preferably 5 μm or less at the thinnest portion. Since the distance between the electrophoretic display layer 15 and the color filter layer 10 is preferably as short as possible from the viewpoint of the viewing angle of the manufactured electrophoretic display device 1, the thickness of the thinnest portion of the overcoat layer 11 exceeds 5 μm. In this case, the viewing angle of the electrophoretic display device is narrowed, and there is a possibility that the effect of the present embodiment cannot be obtained sufficiently.

  For the transparent electrode layer 12, a carbon material, a thiophene compound, or the like can be used in addition to a metal material of a conductive material having high light transmittance such as indium tin oxide (ITO) or indium zinc oxide (IZO). For forming the transparent electrode layer 12, conventional techniques such as a dry film forming method such as a vapor deposition method, a sputtering method, and a CVD method, and a wet film forming method using a coating liquid can be used.

  For the conductive adhesive 16, a synthetic resin adhesive such as an acrylic resin or a urethane resin is suitable, and an adhesive using a high dielectric resin is particularly preferable.

  By using an adhesive having the same components as the binder resin 14 to be described later for the conductive adhesive 16, the affinity at the interface of the resin is increased and divergence hardly occurs, and the dielectric constant is similar, There is an advantage that the voltage applied to the microcapsule 13 tends to be constant on the surface.

  For the back substrate 18 that forms the back electrode substrate 19, glass, polyvinyl chloride, polyester, synthetic resin such as polyethylene terephthalate, natural resin, or the like can be used alone or in combination, and the shape is not particularly limited.

  The light source 2 is disposed on one end side or both end sides of the transparent light guide plate 4 and may be either a point light source or a line light source such as an LED (light emitting diode) or a rod-like fluorescent lamp.

  FIG. 2 is a schematic view of microcapsules included in a microcapsule display layer of a microcapsule type electrophoretic display sheet according to an embodiment of the present invention.

  As shown in FIG. 2, the microcapsules 13 included in the electrophoretic display layer 15 are enclosed inside the microcapsule shell 23 in a state of being dispersed in white particles 20, colored particles 21, and a dispersion medium 22. In other words, the electrophoretic display layer 15 contains microcapsules in which positively charged first color electrophoretic particles and negatively charged second electrophoretic particles are encapsulated in a liquid dispersion medium. The average particle size of the microcapsules 13 is preferably 20 to 60 μm, and can be purified by any method such as sieving or specific gravity separation.

As the colored particles 21, in addition to inorganic pigments such as inorganic carbon, fine powders such as glass or resin, and composites thereof can be used. As the white particles 20, known white inorganic pigments such as titanium oxide, silica, alumina, and zinc oxide, organic compounds such as vinyl acetate emulsion, and composites thereof can be used.
In addition, the white particles 20 and the colored particles 21 impart desired surface charges by treating the surface of the particles with various surfactants, dispersants, organic and inorganic compounds, metals, and the like as necessary. In addition, the dispersion stability can be improved by preventing aggregation due to electrostatic force between different kinds of particles in the dispersion medium 22.

  As the dispersion medium 22, a solvent in which aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, various esters, alcohols, or other resins are used alone or appropriately mixed can be used. , And encapsulated in a microcapsule 13 manufactured using a known method such as a phase separation method such as mixed coacervation, an interfacial polymerization method, or an in-situ method. Examples of capsule shells include gum arabic, methacrylic acid resin, urea resin, and urea resin.

  The microcapsule 13 is dispersed in a dispersion containing water as a main component, and a binder resin 14 made of a dielectric resin such as urethane resin, acrylic resin, polypropylene resin, phenol resin, or polylactic acid is added to the microcapsule 13. A coating liquid for the capsule 13 is formed. A suitable range of the solid content weight ratio with respect to the total weight in the coating liquid is wide, approximately 20 to 60%, because it depends on the coating method of the coating liquid. The binder resin 14 can be used alone or in combination.

  As a method of coating the microcapsule 13 coating liquid on the transparent light guide plate 4, various methods such as die coating, bar coating, micro gravure coating, and screen printing can be adopted.

  In the electrophoretic display device 1 of the present invention having the above-described structure, the light emitted from the light source 2 propagates through the transparent light guide plate 4 and is emitted to the color filter layer 10 and the electrophoretic display layer 15 side. . This prevents a decrease in brightness due to the formation of the color filter layer 10 and the like, and allows the display surface to be visually recognized even in a dark environment. It can be used without problems even under direct sunlight.

  The electrophoretic display device 1 of the layer formed as shown in FIG. 1 can display by applying voltage from the transparent electrode layer 12 and the back electrode substrate 19 side, and selectively applies positive or negative voltage to the electrodes. In this way, colors can be expressed.

  As shown in the cross-sectional view of FIG. 1, the electrophoretic display layer 15 includes a large number of microcapsules 13. By controlling the direction of the electric field of the electrode layer, the particles in the microcapsules 13 are dispersed based on the principle described above. It can be displayed by moving it.

Since each particle in the microcapsule 13 of the electrophoretic display layer 15 is dispersed in a highly viscous dispersion medium 22, once the electric field is applied, the position of the particle does not change even when the power is turned off. In this way, since the display image has a memory property that does not disappear, an electric field may be applied only at the time of rewriting.

Examples of the present invention will be described below.
First, the microcapsule 13 was produced as follows. Dispersed in a tetrachloroethylene solvent are a titanium oxide powder (white particles 20) having an average particle diameter of 3 μm coated with a polyethylene resin and a carbon black powder (colored particles 21) having an average particle diameter of 4 μm surface-treated with alkyltrimethylammonium chloride. A dispersion was prepared.

Next, the dispersion was mixed with an aqueous solution in which gelatin and sodium polystyrene sulfonate were mixed in water, and stirred with a homogenizer at a liquid temperature of 40 ° C. to obtain an emulsion solution.
Next, the obtained emulsion solution and an aqueous solution prepared by mixing gum arabic with water adjusted to 40 ° C. are mixed using a dispenser, the solution is adjusted to pH 4 using acetic acid, and microcapsules are obtained by coacervation. A shell 23 was formed.

  Further, after the liquid temperature is lowered to 5 ° C., a 37 wt% formalin solution is added to cure the microcapsule shell 23, and black particles (carbon black particles) are dispersed as white particles 20 (titanium oxide particles) and colored particles 21. The microcapsule 13 in which the transparent dispersion medium 22 was enclosed was obtained. Thereafter, by sieving, a microcapsule group having an average particle diameter based on volume of 45 μm and a ratio of microcapsules 13 included in a range of particle diameters from 30 μm to 65 μm was 75% or more was obtained.

  Next, the microcapsule 13 dispersed in pure water having a solid content of 40% by weight is mixed with a urethane binder resin 14 having a solid content of 40% by weight, a surfactant, and a thickener to prepare a microcapsule coating solution. did.

  An undercoat layer liquid dialomer IJ2101 for ink jet (Daiichi Seika Kogyo Co., Ltd.) having a thickness of 10 μm was formed on a polycarbonate transparent light guide plate 4 sheet having a thickness of 700 μm.

  A color filter layer 10 was formed by printing red, green, and blue as color inks corresponding to each pixel using an inkjet apparatus on the basis of the alignment pattern at the edge of the substrate on the image receiving layer.

Next, on the surface of the color filter layer 10, a coating liquid in which zirconium oxide as a refractive index adjusting agent was dispersed in an acrylic resin as an overcoat layer 11 was formed with a film thickness of 5 μm using a bar coater.
Regarding the refractive index of the overcoat layer 11 described above, when the overcoat layer 11 was separately formed on the substrate and the refractive index was measured, the average refractive index was 1.54. Since the average refractive index of the transparent light guide plate 4 formed in this example was 1.58, the difference in refractive index between the two was 0.04, which was within 5% of the average refractive index of the transparent light guide plate 4. It was.

  Next, an ITO layer as a transparent electrode layer 12 is deposited on the surface of the overcoat layer 11 described above, and a microcapsule coating solution is further coated on the ITO layer so as to have a film thickness of 24 μm. The electrophoretic display layer 15 was obtained by drying.

  Furthermore, the back electrode of the active matrix was bonded to the front plate produced by forming the conductive adhesive 16 layer on the microcapsule 13 layer. Further, by connecting with a light source or a light source cover, a light source integrated microcapsule type electrophoretic display device was obtained. When this was driven, the desired operation was obtained without problems. Further, the light source 2 of the front light did not cause a decrease in brightness, and the display image could be visually recognized even in a dark environment.

DESCRIPTION OF SYMBOLS 1 ... Electrophoretic display device 2 ... Light source 3 ... Light source cover 4 ... Transparent light-guide plate 5 ... Front light part 6 ... Light incident surface 7 ... Light emission surface 8 ... -Undercoat layer 9 ... Color ink layer 10 ... Color filter layer 11 ... Overcoat layer 12 ... Transparent electrode layer 13 ... Microcapsule 14 ... Binder resin 15 ... Electrophoresis Display layer 16 ... conductive adhesive 17 ... pixel electrode 18 ... back substrate 19 ... back electrode substrate 20 ... white particles 21 ... colored particles 22 ... dispersion medium 23 ...・ Microcapsule shell

Claims (5)

A light source;
A transparent light guide plate that introduces light radiated from the light source into the interior and emits light propagating through the light exit surface that is one surface in the thickness direction ;
A color filter layer formed on the light exit surface of the transparent light guide plate via an undercoat layer ;
An overcoat layer formed on the surface of the color filter layer opposite to the undercoat layer;
A transparent electrode layer formed on the surface of the overcoat layer opposite to the color filter layer ;
An electrophoretic display layer formed on the surface of the transparent electrode layer opposite to the overcoat layer and containing microcapsules;
A back electrode substrate comprising a pixel electrode and a back substrate formed on a surface opposite to the transparent electrode layer of the electrophoretic display layer via a conductive adhesive layer ;
A first slope that is inclined with a constant upward slope along the light propagation direction inside the transparent light guide plate on the other surface in the thickness direction of the transparent light guide plate, which is the surface opposite to the light exit surface And a second inclined surface which is inclined with a descending gradient greater than the ascending gradient along the light introduction direction from the ridge line which is the uppermost end of the first inclined surface to the transparent light guide plate. And a ridge portion that reflects a part of the light introduced into the transparent light guide plate in the light exit surface direction is continuously formed along the other surface,
Further, in order to reduce the difference between the refractive index of the transparent light guide plate and the refractive index of the undercoat layer, and the difference between the refractive index of the undercoat layer and the refractive index of the overcoat layer, the undercoat layer and A regulator for adjusting the refractive index is added to the material forming the overcoat layer,
An electrophoretic display device characterized by the above. The difference between the refractive index of the transparent light guide plate and the refractive index of the undercoat layer, and the difference between the refractive index of the undercoat layer and the refractive index of the overcoat layer are 0.2 or less, respectively. The electrophoretic display device according to claim 1. The electrophoretic display layer includes a microcapsule in which a positively charged first color electrophoretic particle and a negatively charged second electrophoretic particle are encapsulated in a liquid dispersion medium. The electrophoretic display device according to claim 1 or 2 . Color after applying an undercoat layer to the light exit surface of the transparent light guide plate that introduces light emitted from the light source into the interior and emits the light propagating inside from the light exit surface that is one surface in the thickness direction Forming a filter layer;
Forming an overcoat layer on the surface of the color filter layer opposite to the undercoat layer;
Forming a transparent electrode layer on the surface of the overcoat layer opposite to the color filter layer ;
Forming an electrophoretic display layer containing microcapsules on the surface of the transparent electrode layer opposite to the overcoat layer ;
A step of forming a back electrode substrate comprising a pixel electrode and a back substrate after applying a conductive adhesive layer to the surface of the electrophoretic display layer opposite to the transparent electrode layer,
A first slope that is inclined with a constant upward slope along the light propagation direction inside the transparent light guide plate on the other surface in the thickness direction of the transparent light guide plate, which is the surface opposite to the light exit surface And a second inclined surface which is inclined with a descending gradient greater than the ascending gradient along the light introduction direction from the ridge line which is the uppermost end of the first inclined surface to the transparent light guide plate. A step of continuously forming, along the other surface, a ridge that reflects a part of the light introduced into the transparent light guide plate in the light exit surface direction;
In order to reduce the difference between the refractive index of the transparent light guide plate and the refractive index of the undercoat layer, and the difference between the refractive index of the undercoat layer and the refractive index of the overcoat layer, the undercoat layer and the overcoat layer And a step of adding a regulator for adjusting the refractive index in the material forming the coating layer,
A method for manufacturing an electrophoretic display device. The difference between the refractive index of the transparent light guide plate and the refractive index of the undercoat layer, and the difference between the refractive index of the undercoat layer and the refractive index of the overcoat layer are 0.2 or less, respectively. A method for manufacturing an electrophoretic display device according to claim 4 .

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