JP2009265272A - Electro-optical display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin type electro-optical display, having both satisfactory reflectance and contrast, and attaining good visibility. <P>SOLUTION: This electro-optical display includes an EC layer 3 having a predetermined display area and presenting a change in colored state based on EC reaction and an electrophoretic layer 5 having a predetermined display area and presenting a change in colored state with the migration of electrophoretic particles, which are superposed one on the other with the EC layer 3 placed on the viewing side. This electro-optical display is manufactured as follows. The EC layer 3 is formed by stacking a first EC layer 3C where first EC elements 2C colored to a first primary color are arrayed, a second EC layer 3M where second EC elements 2M colored to a second primary color are arrayed and a third EC layer 3Y where third EC elements 2Y colored to a third primary color are arrayed, the EC elements 2C-2Y respectively display colorless and transparent color, and the EC elements 2C-2Y are arrayed not to overlap each other when viewed from the viewing side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electro-optic display device that displays an image by modulating the reflectance of external light.

  2. Description of the Related Art In recent years, research and development have been actively conducted on reflective display devices having the same visibility as that of paper media by modulating the reflectance of external light to display an image. As a device that realizes such a display device, for example, a reflective liquid crystal display device, an electrophoretic display device that can modulate the reflection state of light by moving electrophoretic particles enclosed in a cell by an electric field, etc. Is mentioned. Since the reflective liquid crystal display device does not require a backlight for display, the space for the backlight can be eliminated and the power can be reduced. Since the electrophoretic display device can be made thinner and lighter, it is expected to be applied to electronic paper and flexible displays that replace paper media.

  In Patent Document 1, a plurality of scanning wirings arranged on an insulating substrate, a plurality of signal wirings arranged so as to intersect via an insulating film, and a thin film transistor are provided at an intersection of the scanning wiring and the signal wiring. An active matrix substrate provided with a reflective pixel electrode connected to the thin film transistor and having a reflective function is described. Furthermore, in Patent Document 1, an RGB region of a color filter is formed in an area corresponding to a reflective pixel electrode on an insulating substrate, and a color filter without a light-shielding film is formed in an area corresponding to between the reflective pixel electrodes. In addition, a reflective liquid crystal display device in which liquid crystal is sandwiched between a counter substrate provided with a common electrode made of a transparent conductive material is described.

  Patent Document 2 discloses an EC layer that exhibits a transparent region and a colored region (for example, a blue region) by an electrochromic (hereinafter referred to as “EC”) reaction in which a colored state is changed by an oxidation-reduction reaction, and a lower part of the EC layer. An electrophoretic layer that exhibits a first color region (for example, a red region) and a second color region (for example, a green region) that are different from the color of the colored region of the EC layer by electric field control in a superposed form, Describes that multicolor display of red, green, blue, and mixed colors thereof is performed.

Patent Document 3 discloses an electrophoretic display element in which a microcapsule containing a pigment or a partition wall for separating the pigment is sandwiched between two electrodes, and an EC display element formed between the two electrodes. A color rewritable display device having a superposed configuration is described. Since this display device has a memory property with respect to display, it is only necessary to give writing energy by the image writing device only when information is rewritten, and it is not necessary to apply energy to maintain the display. Therefore, after writing information, only the display device is disconnected from the image writing device, and it can be easily carried like a paper medium, stacked, arranged, or read text information by hand.
Japanese Patent Laid-Open No. 2000-122093 (FIG. 1 etc.) JP 10-161161 A (FIG. 4 etc.) Japanese Patent Laid-Open No. 2004-286977 (FIG. 1 etc.)

  In Patent Document 1, a reflective liquid crystal display device is used. In Patent Documents 2 and 3, an electrophoretic display device is used to form a reflective display device. In Patent Document 1, color display is realized by overlaying a color filter on the liquid crystal layer, and in Patent Documents 2 and 3, color display is realized by overlaying an EC display element on the electrophoretic layer. ing.

  However, in the reflective liquid crystal display device of Patent Document 1, since the transmittance of the color filter is basically fixed, a sufficient reflectance is not obtained on the viewing side. Further, even when the EC display element and the electrophoretic display element disclosed in Patent Documents 2 and 3 are used, at present, a display device having sufficient reflectivity and contrast sufficient to replace a paper medium has been realized. Absent. Accordingly, an object of the present invention is to provide a thin electro-optic display device having both sufficient reflectance and contrast and high visibility.

One electro-optic display device of the present invention that has achieved the above object is:
An EC layer having a predetermined display area and exhibiting a change in colored state based on electrochromic (EC) reaction, and an electrophoretic layer having a predetermined display area and exhibiting a change in colored state as electrophoretic particles move And an electro-optic display device configured such that the EC layer is on the viewing side,
The EC layer includes a first EC layer in which first EC elements that can be colored in the first primary color are arranged, and a second EC layer in which second EC elements that can be colored in the second primary color are arranged. And a third EC layer in which third EC elements that can be colored in the third primary color are arranged, and the first to third EC elements can each display a colorless transparent color, and When viewed from the viewing side, the first EC element, the second EC element, and the third EC element are arranged so as not to overlap each other.

  In the electro-optical display device, the first EC element, the second EC element, and the third EC element may be arranged so as to be shifted from each other by 1/2 element or 1/3 element as viewed from the viewing side. desirable.

One electro-optic display device of the present invention that has achieved the above object is:
An EC layer having a predetermined display area and exhibiting a change in colored state based on electrochromic (EC) reaction, and an electrophoretic layer having a predetermined display area and exhibiting a change in colored state as electrophoretic particles move And an electro-optic display device configured such that the EC layer is on the viewing side,
The EC layer includes a first EC layer in which first EC elements that can be colored in the first primary color are arranged, and a second EC layer in which second EC elements that can be colored in the second primary color are arranged. And a third EC layer in which third EC elements that can be colored in the third primary color are arranged, and the first to third EC elements can each display a colorless transparent color, and When viewed from the viewing side, any two or more layers of the first EC element, the second EC element, and the third EC element are arranged so as to overlap each other.

  In the electro-optical display device, the first primary color may be cyan, the second primary color may be magenta, and the third primary color may be yellow.

  In the electro-optical display device, the first primary color may be blue, the second primary color may be green, and the third primary color may be red.

  In the electro-optical display device, it is desirable to form the second EC layer thicker than the first EC layer and the third EC layer thicker than the second EC layer.

  In the electro-optical display device, it is desirable that the display color density be adjusted by a combination of a colored state / colorless transparent state of a plurality of same-color EC elements in a specific region.

  In the electro-optical display device, a mode in which a touch panel is formed on the EC layer is preferable.

  According to the present invention, since the electrophoretic layer suitable for displaying an achromatic color (grayscale) is disposed on the back side (the side opposite to the viewing side) of the EC layer, the color elements are enriched, and the EC layer It is possible to display an expressive full-color image with high gradation that cannot be expressed only by color display.

  According to the present invention, since the EC layer can display a colorless and transparent color, an achromatic image by the electrophoretic layer can be displayed more clearly.

(Embodiment 1)
Hereinafter, an electro-optic display device according to a first exemplary embodiment of the present invention will be described in detail with reference to the drawings.

1. FIG. 1 is a schematic cross-sectional view illustrating an example of an electro-optic display device according to a first embodiment of the present invention. In FIG. 1, the electro-optical display device 1 is configured by superposing an EC layer 3, an electrophoretic layer 5, an EC layer 3 and an electronic circuit layer 6 for driving the electrophoretic layer 5.

  The EC layer 3 is a transmissive display layer that exhibits a transparent chromatic color and colorless and transparent by adjusting the applied voltage, and the electrophoretic layer 5 is a light reflective display device that can modulate the reflectance of light. The viewing side of the electro-optic display device 1 is the EC layer 3 side.

  More specifically, the EC layer 3 includes an EC layer 3C including EC elements 2C formed in a matrix, an EC layer 3M including EC elements 2M formed in a matrix, and an EC element 2Y formed in a matrix. It is composed of the EC layer 3Y. Details of the EC elements 2C to 2Y will be described later.

  The electrophoretic layer 5 includes the electrophoretic elements 4 formed in a matrix. Details of the electrophoretic element 4 will be described later.

  The electronic circuit layer 6 is an electronic circuit for driving the EC element 2C and the electrophoretic element 4, the electronic circuit layer 6a is an electronic circuit for driving the EC element 2M, and the electronic circuit layer 6b is an EC element 2Y. It is an electronic circuit for driving.

  In the first embodiment, the electronic circuit layer 6 for driving the EC element 2C is exemplified for the configuration for driving the electrophoretic element 4 in addition to the EC element 2C. However, the present invention is not limited to this configuration. The electronic circuit layer for driving and the electronic circuit layer for driving the electrophoretic element 4 may be formed separately. Alternatively, the electronic circuits that drive the EC elements 2C to 2Y and the electrophoretic element 4 may be formed together in one electronic circuit layer 6.

  In the configuration of the electro-optical display device described above, the total light transmittance of the laminate of the EC layers 3C to 3Y when colorless and transparent is preferably 60% or more. This is because the achromatic color image exhibited by the electrophoretic layer 5 can be projected more clearly by increasing the total light transmittance of the laminate.

  Moreover, it is preferable that the minimum value of the light reflectance of the electrophoretic layer 5 is 7% or less, and it is preferable that the maximum value of the light reflectance is 40% or more. By configuring the electro-optic display device in this way, the brightness and contrast of the electro-optic display device are improved. The total light transmittance is measured in accordance with JIS K7105 (ASTM D1003) relating to the optical property test method for plastics.

  The reflectance (%) of the electrophoretic layer 5 is measured by a spectrophotometer. As a spectrophotometer, SpectroEye (registered trademark) manufactured by Greater Kumakbeth can be used. For reference, the reflectance of the white background of newspaper measured by spectroeye is about 60%.

2. EC Element In FIG. 1, an EC element 2C that exhibits the first primary color, cyan, is transparent between the first pixel electrode (common electrode) 7C and the second pixel electrode (pixel electrode) 8C by an oxidation-reduction reaction. An EC material layer 9C capable of selecting whether to be colored (colored state) or colorless and transparent is sandwiched. The first pixel electrode (common electrode) 7C has a fixed potential, and the second pixel electrode (pixel electrode) 8C is addressed to a potential corresponding to a signal for each pixel.

  In the present invention, “colorless and transparent” does not only mean complete transparency, but the light transmittance is low due to the characteristics of the first pixel electrode 7C, the second pixel electrode 8C, and the EC material layer 9C to be used. Is included, but at least the total light transmittance is 60% or more. Further, “colorless and transparent” does not only mean completely colorless, but also includes a case where a small amount of chromatic color remains depending on the characteristics of the EC material layer 9C to be used regardless of the voltage application state. The total light transmittance (%) of the EC layer 3C is measured by the amount of light transmitted through the laminate of the first pixel electrode 7C, the EC material layer 9C, and the second pixel electrode 8C. At the time of measurement, there is a transparent base material, an adhesive, or the like outside the EC layer 3C, that is, outside the first pixel electrode 7C or the second pixel electrode 8C, and the effect of the presence on the total light transmittance Is not negligible, the total light transmittance (%) of the EC layer 3C can be reduced by removing the decrease in the total light transmittance (%) due to the presence of the transparent substrate or adhesive by calculation. Can be sought.

  Although the configuration of the EC layer 3C including the EC element 2C has been described above, the EC element 2M exhibiting the magenta color that is the second primary color and the EC element 2Y exhibiting the yellow color that is the third primary color are similarly formed in a matrix. The EC elements 2C to 2Y are arranged so as not to overlap each other when viewed from the viewing side.

  The primary colors constituting the color of the EC layer 3 include a combination of the first primary color as cyan, the second primary color as magenta, and the third primary color as yellow, the first primary color as blue, the second primary color as green, and the third primary color as red. It can also take the structure.

  Examples of materials for the EC material layers 9C to 9Y include 1,4-diacetylbenzene as a cyan material, dimethyl terephthalate as a magenta material, and diethyl 4,4'-biphenyldicarboxylate as a yellow material, respectively. Those dissolved in -2-pyrrolidone can be used as the CMY3 primary colors. An anthraquinone dye or styryl spiropyran dye as a red material, an aromatic amine dye or viologen dye as a green material, and an organic EC dye such as a viologen dye or a pyrazoline dye as a blue material as RGB three primary colors it can.

  In the case of being colorless and transparent, on the viewing side, the color reflected from the electrophoretic layer 5 which is the base (background) is reflected as it is.

  The color density can also be controlled by changing the DC voltage application time and voltage value. That is, it is also possible to control the color density by changing the application time or giving a width to the applied voltage. Alternatively, the plurality of EC elements 2C, the plurality of EC elements 2M, and the plurality of EC elements 2Y may be one pixel, and the color density may be adjusted depending on the number of EC elements that are in a colored state in one pixel. For example, when four EC elements 2C, four EC elements 2M, and four EC elements 2Y are included in one pixel, three EC elements 2C are turned on and one is turned off. The EC element 2M is turned on to turn off the three, and all the EC elements 2Y are turned on.

  Furthermore, the color density can also be controlled by adjusting the voltage application time per unit time for one EC element (2C to 2Y). For example, a method of increasing or decreasing the number, width, and height of voltage pulses applied per second may be employed.

  Since the EC layers 3C to 3Y function as a transmissive display layer, the common electrodes 7C to 7Y and the pixel electrodes 8C to 8Y need to be made of a transparent conductive material. As the transparent conductive material, indium tin oxide (ITO), indium zinc oxide (IZO), or the like can be used.

  The EC material layers 9C to 9Y can be applied on the common electrode 7 by an ink jet method, for example. The EC material layers 9C to 9Y may be liquid materials that can be filled in the cells having the spacer 10 as a side wall. It is preferable to use a solid or semi-solid form that can retain its shape without flowing out of the liquid.

3. Electrophoresis Layer Next, the electrophoresis layer 5 will be described. In FIG. 1, the electrophoretic layer 5 is constituted by sandwiching a microcapsule 11 enclosing a dispersion liquid between a third pixel electrode (pixel electrode) 12 and a fourth pixel electrode (common electrode) 13. The element 4 is provided. The common electrode 13 has a fixed potential, and the pixel electrode 12 is addressed to a potential corresponding to a signal for each pixel.

  The dispersion is composed of an insulating liquid in which charged electrophoretic particles and a dye are dissolved. When a voltage is applied to the dispersion by the pixel electrode 12, electrophoretic particles having a charge move to an electrode having a polarity opposite to that of the charge. When the electrophoretic particles gather on the observer side electrode (pixel electrode 12 in FIG. 1), the color of the electrophoretic particles is displayed. On the other hand, when the electrophoretic particles gather on the electrode opposite to the observer side (common electrode 13 in FIG. 1), the observer visually recognizes the color of the insulating liquid. That is, the display is switched depending on the color difference between the electrophoretic particles and the insulating liquid. For example, if the electrophoretic particles are colored white and the insulating liquid is colored black, white or black can be displayed by switching the voltage applied to the pixel electrode 12. Of course, if white and black are switched for each pixel, grayscale display can be performed.

  The microcapsule 11 can be composed of a wall body made by coacervation with gelatin and gum arabic. When white electrophoretic particles are used, titanium oxide can be preferably used. When black electrophoretic particles are used, carbon black can be preferably used. As a solvent for the dispersion (the insulating liquid), a hydrocarbon compound such as toluene and kerosene and / or a silicon compound solvent such as silicone oil can be preferably used.

  In the present embodiment, the minimum value of the light reflectance of the electrophoretic layer 5 (the state in which the electrophoretic layer 5 is dark (black)) is 7% or less, and the maximum value of the light reflectance (the electrophoretic layer 5 is bright). It is preferable to configure so that (white) is 40% or more. The light reflectance (%) of the electrophoretic layer 5 is such that light incident on the laminated body of the third pixel electrode (pixel electrode) 12, the microcapsule 11, and the fourth pixel electrode (common electrode) 13 is reflected by the laminated body. It is measured by the amount of light. In the case of measurement, even if there is a transparent base material, an adhesive, or the like outside the third pixel electrode 12, and the influence on the reflectance due to the presence cannot be ignored, the transparent base material, the adhesive, etc. The light reflectance (%) of the electrophoretic layer 5 can be obtained by removing the decrease in reflectance (%) due to the presence by calculation. In addition, since the light reflectance largely depends on the reflection of light by the microcapsule 11, even if a transparent base material or the like is present outside the fourth pixel electrode 13, the influence on the reflectance due to the presence is normal. Can be ignored.

  As a method for realizing the electrophoretic layer 5 with high contrast, (1) a method in which white electrophoretic particles are dispersed in an insulating liquid in which a black pigment is dissolved, and (2) a white pigment is dissolved. A method of dispersing black electrophoretic particles in an insulating liquid, (3) black electrophoretic particles in an insulating liquid, and white electrophoretic particles charged with a polarity opposite to that of the black electrophoretic particles (4) Electrophoretic particles in which the hemisphere side is colored white and the other hemisphere side is colored black and the electric polarity of the white portion and the black portion are opposite in polarity are arranged between the pixel electrode 12 and the common electrode 13. A method of encapsulating in can be considered.

  2 to 4 are plan views seen from the viewing side of the electro-optic display device shown in FIG. 1, and represent the positional relationship between the EC elements 2C to 2Y. 2 shows the EC elements 2C to 2Y in a stripe arrangement, FIG. 3 shows a mosaic arrangement, and FIG. 4 shows a delta arrangement.

(1) Stripe arrangement The first to third primary colors are arranged in a vertical row, that is, in a stripe shape.
Since the stripe arrangement is suitable for displaying lines, figures, and characters, it is applied to a high-definition display such as a personal computer.

(2) Mosaic arrangement Using the stripe arrangement as a reference, the EC elements 2C to 2Y in the second row are shifted laterally by one pixel (one column) with respect to the first row, and the EC elements 2C to 2 in the third row 2Y is configured by shifting horizontally by 2 pixels (2 columns) with respect to the first row. The configuration of the fourth row is the same as that of the first row. If the EC elements are arranged in a mosaic pattern, a natural image without a jagged feeling can be obtained compared to the case of a stripe array, and thus the EC elements are preferably applied to a television screen or the like.

(3) Delta arrangement The EC elements 2C to 2Y in the second and fourth rows are shifted horizontally by 1.5 pixels (1.5 columns) with respect to the stripe arrangement. The configuration of the third and fifth rows is the same as that of the first row. For example, when attention is paid to the EC element 2C in the second row, the EC element 2C in the first row and the third row is formed in the most distant place. If the EC elements are arranged in a delta arrangement, the same color pixels are not adjacent (continuous), and a natural image with less jaggedness can be obtained. Therefore, it is preferably applied to a television screen or the like.

  In the delta arrangement, the EC elements in the first row and the second row, or the second row and the third row are shifted from each other by ½ elements unless the colors are distinguished. Is. The degree of deviation is not limited to ½ elements, but may be arranged so that １ ／ elements deviate from each other. If it is configured to be shifted by 1/3 elements, the spatial period in which the same color is repeated becomes longer, so that the jaggedness of the image is further improved.

  In addition, although there is no restriction | limiting in particular in the arrangement | sequence method of the electrophoretic element 4, It is desirable to arrange | position corresponding to the arrangement | sequence of EC element 2C-2Y.

4). Electronic Circuit Layer Next, a preferred form of the electronic circuit layer 6 will be described, but it is only an example and is not limited to the one described below. As shown in FIG. 5, in the present embodiment, the electronic circuit layer 6 for driving the EC element 2C and the electrophoretic element 4 is sandwiched between the EC layer 3C and the electrophoretic layer 5. The electronic circuit layer 6 includes at least three types of active elements, that is, a first switching thin film transistor 14, a second switching thin film transistor 15, and a driving thin film transistor 16. As a transistor type, a field effect transistor, a bipolar transistor, a thyristor, an IGBT, or the like can be used, but it is preferable to select a field effect transistor with a small off-state current. The control electrode in this case is a gate electrode, and the first electrode and the second electrode correspond to either the source electrode or the drain electrode. In general, a so-called grounded source circuit configuration in which the source electrode side is grounded is often employed.

  FIG. 5 is an electronic circuit diagram showing a connection relationship between the EC element 2C and the electrophoretic element 4 described above, the first switching thin film transistor 14, the second switching thin film transistor 15, and the driving thin film transistor 16. In FIG. 5, an EC element signal line 21 for transmitting a display signal to the EC element 2C and an electrophoretic element signal line 22 for transmitting a display signal to the electrophoretic element 4 are arranged in parallel in the vertical direction of the drawing. Wired to On the other hand, a common scanning line 23 is wired in the horizontal direction of the drawing, and a matrix structure is formed by the EC element signal line 21 / electrophoretic element signal line 22 and the common scanning line 23. A control electrode 14 g of the first switch thin film transistor 14 and a control electrode 15 g of the second switch thin film transistor 15 are connected to the common scanning line 23.

  The first electrode 14 a of the first switch thin film transistor 14 is connected to the EC element signal line 21, and the first electrode 15 a of the second switch thin film transistor 15 is connected to the electrophoretic element signal line 22. . On the other hand, the second electrode 14b of the first switching thin film transistor 14 is connected to the control electrode 16g of the driving thin film transistor 16 of the EC element 2, and the second electrode 15b of the second switching thin film transistor 15 is the pixel of the electrophoretic element 4. It is connected to the electrode 12 (see FIG. 1).

  The first electrode 16a of the driving thin film transistor 16 is grounded, the second electrode 16b is connected to the pixel electrode 8 (see FIG. 1) of the EC element 2C, and the common electrode 7C (see FIG. 1) of the EC element 2C is constant. It is connected to a power supply Vcom that provides a potential. When the common electrode 7C is uniformly formed on the entire surface of the matrix structure, the power source Vcom does not need to be individually wired up to each matrix, but can be individually wired with aluminum or copper having good electrical conductivity. The time taken for the potential of the entire common electrode 7C to become a predetermined potential is shortened. Further, if the common electrode 7C is not formed in the entire matrix structure but is formed for each line or each EC element 2C, it is necessary to wire the power supply Vcom individually.

  Although the first electrode 16a of the driving thin film transistor 16 is grounded as described above, it may be directly grounded or indirectly grounded. For example, a passive element such as a capacitive element (not shown) may be interposed. When the capacitive element is used, the driving thin film transistor 16 and the EC element 2C can be protected against a surge current.

  The second electrode 14b of the first switch thin film transistor 14 and the second electrode 15b of the second switch thin film transistor 15 are also grounded, but when they are grounded, the first capacitor element 27 and the second capacitor element 28 are also grounded. May be interposed. By using the second capacitor element 28, the display state 27 of the electrophoretic element 4 can be maintained. Further, by using the first capacitor element 27, the on / off state of the driving transistor 16 can be maintained, and the display state of the EC element 2C can be maintained.

  The grounding destination of the first and second capacitive elements 27 and 28 may be the common electrode 13 of the electrophoretic element 4. In this case, a via hole (not shown) penetrating the electrophoretic layer 5 is provided. This complicates the manufacturing process of the electro-optic display device.

  FIG. 6 is a circuit diagram showing another grounding method for the first and second capacitive elements 27 and 28. According to this circuit diagram, the ground destination of the first and second capacitive elements 27 and 28 is a common ground line 24 provided in parallel with the common scanning line 23 provided in the electronic circuit layer 6. The common ground line 24 can be grounded outside through the electronic circuit layer 6. If such a common ground line 24 is formed, the ground structure of the first and second capacitive elements 27 and 28 can be accommodated in the electronic circuit layer 6, so there is no need to provide a via hole as described above. The manufacturing process of the electro-optic display device can be simplified.

Since the electronic circuit layer 6 in the first embodiment is configured at a position sandwiched between the EC layer 3C and the electrophoretic layer 5, the electronic circuit layer 6 preferably has a high light transmittance. From this viewpoint, it is preferable to use a transparent thin film transistor as the thin film transistor. In the present invention, a transparent thin film transistor refers to an electrode material (if the thin film transistor is a field effect transistor), a transparent oxide conductor (such as the above-mentioned ITO or IZO) on a source electrode / drain electrode or a gate electrode. It shall mean the one using. Furthermore, transparency is increased by configuring the gate insulating film disposed between the gate electrode and the active layer with a transparent insulator such as Y ₂ Ox. An amorphous oxide semiconductor film (InGaZnO ₄ ) is preferably used as the active layer of the transistor, and a PET film can be preferably used as the base of the electronic circuit layer 6.

  As shown in FIG. 1, an anisotropic conductive film 17 (ACF) formed of a thermosetting resin in which conductive fine particles (conductive filler) are dispersed is used for connection between the EC layer 3C and the electronic circuit layer 6. : Anisotropic Conductive Film), the driving thin film transistor 16 of the electronic circuit layer 6 and the pixel electrode 8C of the EC element 2C can be easily connected. As a connection method, first, an anisotropic conductive film 17 is sandwiched between the electronic circuit layer 6 and the EC layer 3C, and conduction between the electronic circuit layer 6 and the EC layer 3C is desired while applying heat with a heater or the like. By applying pressure from the vertical direction of the anisotropic conductive film 17 to the place, the conductive fillers can come into contact with each other, and the connection point 18 in the vertical direction of the anisotropic conductive film 17 can be formed. In addition to the anisotropic conductive film 17, an anisotropic conductive paste having high heat resistance can also be used.

  The driving thin film transistor 16 of the electronic circuit layer 6 and the pixel electrode 8C of the EC element 2C function as the EC element 2C as long as they are connected at least at one point. More contacts with the 2C pixel electrode 8 are better. This is because the transparent material such as ITO, which is the material of the pixel electrode 8, has lower electrical conductivity than aluminum or copper, so that the driving thin film transistor 16 of the electronic circuit layer 6 and the pixel electrode 8C of the EC element 2C This is because when there are few connection points, color unevenness and display delay occur in the pixel.

  When there are many contacts, the time until the entire pixel electrode 8C becomes equipotential can be shortened, so that the display state can be switched at high speed. Accordingly, it is desirable that the anisotropic conductive film 17 is energized in a linear region instead of a dot shape, and it is particularly desirable that the anisotropic conductive film 17 be disposed over a length equivalent to one side of the pixel electrode 8C.

  As described above, the structure on the viewer side of the electrophoretic layer 5 according to the first embodiment, for example, the EC layer 3C functions as a transmissive display layer. It is necessary not to disturb the light transmission. For this reason, it is desirable that the anisotropic conductive film 17 is made of a transparent film material.

5. Next, a method for driving the electronic circuit layer 6 will be described. As shown in FIG. 1, the EC element 2C and the electrophoretic element 4 are arranged so as to overlap each other, and depending on the display color of the electrophoretic element 4 and the display color of the EC element 2C (or 2M, 2Y), Since an observable color is determined, the EC element 2C and the electrophoretic element 4 must be colored with a predetermined timing. First, a predetermined voltage is addressed to the EC element signal line 21 connected to the EC element 2C to be displayed, and the electrophoretic element signal connected to the electrophoretic element 4 facing the EC element 2C. The line 22 is addressed with a predetermined voltage. In this state, the preparation for simultaneously coloring the EC element 2C and the electrophoretic element 4 is completed.

  Next, an ON voltage (for example, 0.7 V) is applied to the common scanning line 23, and the control electrode 14g of the first switch thin film transistor 14 and the control electrode 15g of the second switch thin film transistor 15 are turned on. When the control electrode 15g is turned on, the first electrode 15a and the second electrode 15b are in a conductive state, the pixel electrode 12 of the electrophoretic element 4 is at a predetermined potential, and the electrophoretic element 4 is in a desired color state. . Further, when the control electrode 14g of the first switching thin film transistor 14 is turned on, the first electrode 14a and the second electrode 14b are brought into conduction, and thereby the control electrode 16g of the driving transistor 16 is turned on. . When the control electrode 16g is turned on, the first electrode 16a and the second electrode 16b become conductive, the pixel electrode 8C of the EC element 2C becomes a predetermined potential, and the color state of the EC element 2C (transparent cyan or colorless and transparent) )

  As described above, in the electro-optical display device according to the present embodiment, the driving timing of the electrophoretic element 4 and the EC element 2C is controlled by one common scanning line 23. The coloration timing of the EC element 2C is not shifted, and stable color or brightness can be displayed. Further, since the scanning line is one common scanning line 23, the aperture ratio of each pixel is increased, so that the amount of light finally seen by the viewer increases.

  The electronic circuit for simultaneously driving the EC element 3C and the electrophoretic element 4 has been described above. However, as described above, the electronic circuit for driving the EC element 2M and the EC element 2Y is also included in the electronic circuit layer 6. It is also possible to include them. For example, the electronic circuit layer may be formed by forming via holes in the EC layer 3C and the EC layer 3M, or by detouring wiring for driving the EC layer 3M and the EC layer 3Y to the periphery of the display area. 6 may be configured to connect the EC layer 3M and the EC layer 3Y.

  As described above, according to the electro-optical display device according to the first exemplary embodiment, the electrophoretic layer suitable for displaying an achromatic color (gray scale) on the back side (the side opposite to the viewing side) of the EC layer. Therefore, it is possible to display an expressive full-color image with a high gradation that cannot be expressed by color display using only the EC layer. Further, since each EC layer can display a colorless and transparent color, an achromatic image by the electrophoretic layer can be displayed more clearly.

(Embodiment 2)
Hereinafter, an electro-optic display device according to Embodiment 2 of the present invention will be described in detail with reference to the drawings.

  FIG. 7 is a schematic cross-sectional view showing an example of an electro-optic display device according to Embodiment 2 of the present invention. The electro-optical display device according to the second embodiment basically has the same configuration as that of the electro-optical display device according to the first embodiment, but the arrangement of the EC element 2C, the EC element 2M, and the EC element 2Y is different. ing. That is, in the electro-optic display device according to the first embodiment, the EC element 2C, the EC element 2M, and the EC element 2Y are arranged so as not to overlap each other when viewed from the viewing side. In the electro-optical display device, the EC element 2C, the EC element 2M, and the EC element 2Y are arranged so as to overlap each other when viewed from the viewing side.

  Therefore, the color displayed on the viewer side is a mixed color by the subtractive color method of transparent chromatic colors (cyan, magenta, yellow) exhibited by the EC element 2C, the EC element 2M, and the EC element 2Y. If all of the EC element 2C, the EC element 2M, and the EC element 2Y are in an on state (a state in which a transparent chromatic color is exhibited), the color on the viewing side is black. On the contrary, if all of the EC element 2C, the EC element 2M, and the EC element 2Y are in an off state (a state of being colorless and transparent), the colored state of the electrophoretic layer 5 is displayed as it is on the viewing side.

  In the electro-optic display device according to the second embodiment, the total light transmittance of the laminate of the EC layer 3C, the EC layer 3M, and the EC layer 3Y when colorless and transparent is the same as that of the electro-optic display device according to the first embodiment. 60% or more is preferable. This is because the achromatic image presented by the electrophoretic layer 5 can be projected more clearly on the viewer side by increasing the total light transmittance of the laminate. In order to realize this, it is desirable that the total light transmittance of each of the EC layer 3C, the EC layer 3M, and the EC layer 3Y when colorless and transparent is 85% or more.

  8 to 10 are diagrams showing color patterns of the electro-optic display device according to the second embodiment of the present invention. 8 to 10 represent the stacking direction of the electrophoretic element 4, the EC element 2C, the EC element 2M, and the EC element 2Y in order from the bottom. On the other hand, the horizontal directions of FIGS. 8 to 10 show variations of the color patterns of the EC element 2C, EC element 2M, and EC element 2Y. All patterns of lighting, non-lighting of each color of cyan, magenta, and yellow are shown. There are 8 types (2 × 2 × 2).

  The color variations of the electrophoretic element 4 are as follows. That is, FIG. 8 shows the case where the electrophoretic element 4 exhibits white (White), FIG. 9 shows the case where the electrophoretic element 4 exhibits an intermediate color (Gray), and FIG. 10 shows the case where the electrophoretic element 4 exhibits black. Each is shown.

  In FIG. 8 in which the electrophoretic element 4 exhibits white (White), white (White), bright cyan (BC), bright magenta (BM), bright yellow (BY), and bright are listed in order from the left side of the drawing. Red (BR), bright blue (BB), bright green (BG), and black (Black).

  In FIG. 9 in which the electrophoretic element 4 exhibits an intermediate color, that is, gray (Gray), in order from the left side of the drawing, gray (Gray), dark cyan (DC), dark magenta (DM), dark yellow (DY), dark red (DR) ), Dark blue (DB), dark green (DG), and black (Black).

  In FIG. 10 in which the electrophoretic element 4 is black, light is not reflected on the electrophoretic element 4 regardless of whether the EC element 2C, the EC element 2M, and the EC element 2Y are on or off. Black is displayed.

  In the electro-optical display device according to the second embodiment, since the EC elements 2C to 2Y are arranged so as to overlap each other when viewed from the viewing side, the area for one pixel when viewed from the viewing side is the electrical according to the first embodiment. Compared to an optical display device, the size is reduced to one-third, and a high-definition image display device is realized while displaying a full color.

  As described above, according to the electro-optical display device according to the second embodiment, the electrophoretic layer suitable for displaying an achromatic color (gray scale) on the back side (the side opposite to the viewing side) of the EC layer. Therefore, it is possible to display an expressive full-color image with a high gradation that cannot be expressed by color display using only the EC layer. Further, since each EC layer can display a colorless and transparent color, an achromatic image by the electrophoretic layer can be displayed more clearly.

  In the second embodiment, the EC elements 2C to 2Y are all overlapped with each other when viewed from the viewing side. However, in order to increase the total light transmittance of the EC layer 3, the EC elements 2C to 2Y are selected. It is also possible to adopt a form in which only any two layers overlap each other.

(Embodiment 3)
In the first or second embodiment, when the three primary colors are cyan, magenta, and yellow, the EC layer 3M is formed thicker than the EC layer 3C, and the EC layer 3Y is formed more than the EC layer 3M. Is preferably formed thick. When the three primary colors are blue, green, and red, it is preferable that the EC layer 3G is formed thicker than the EC layer 3B and the EC layer 3R is formed thicker than the EC layer 3G. The color density and transparency of the EC layer can of course be adjusted by electrical control of the EC element, but an electronic circuit customized to the characteristics of the EC material must be constructed. On the other hand, if the difference in the characteristics of the EC material is adjusted by setting the thickness of the EC layer, the configuration of the electronic circuit can be simplified, thereby contributing to the improvement of the operation speed and energy saving of the electronic circuit.

(Embodiment 4)
In the first to third embodiments, a touch panel can be formed on the viewing side. The touch panel can detect and specify a position where a fingertip, a pen tip, or the like is physically contacted by wiring or the like formed in a matrix. For example, information written on the electronic book by the pressure of the pen can be displayed or stored on the electronic paper.

  The touch panel is categorized by operating principle. Lightweight and low-cost resistive membrane method (analog resistive membrane method), high transmittance capacitance method, high transmittance and high durability ultrasonic surface acoustic wave method, transmittance Among them, an infrared light shielding method that is high and has few malfunctions, among others, the resistive film method is a method that is suitable for use in electronic paper and a flexible display from the viewpoint of low manufacturing cost and high flexibility.

  The electro-optical display device of the present invention includes notebook PCs, PDAs, mobile phones, electronic books, electronic newspapers, electronic papers such as electronic library, bulletin boards such as calendars, signboards, posters, blackboards, calculators, home appliances, automobile supplies, etc. In addition to a display unit, a card display unit such as a point card, an IC card, an electronic advertisement, an electronic price tag, and an electronic score, it is also suitably used as a rewritable paper that drives a display medium using external information input means.

FIG. 1 is a schematic cross-sectional view of an electro-optic display device according to Embodiment 1 of the present invention. FIG. 2 is a plan view of the electro-optic display device according to the first embodiment of the present invention. FIG. 3 is a plan view of the electro-optic display device according to the first embodiment of the present invention. FIG. 4 is a plan view of the electro-optic display device according to the first embodiment of the present invention. FIG. 5 is an electronic circuit of the electro-optic display device according to the first embodiment of the present invention. FIG. 6 is another electronic circuit of the electro-optical display device according to the first exemplary embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of an electro-optic display device according to Embodiment 2 of the present invention. FIG. 8 is a diagram illustrating a color pattern of the electro-optic display device according to the second embodiment of the present invention. FIG. 9 is a diagram illustrating a color pattern of the electro-optic display device according to the second embodiment of the present invention. FIG. 10 is a diagram illustrating a color pattern of the electro-optic display device according to the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electro-optical display device 2 EC element 3 EC layer 4 Electrophoretic element 5 Electrophoretic layer 6 Electronic circuit layer 7 First pixel electrode (common electrode)
8 Second pixel electrode (pixel electrode)
9 EC material layer 10 Spacer 11 Microcapsule 12 Third pixel electrode (pixel electrode)
13 Fourth pixel electrode (common electrode)
14 First switch thin film transistor 15 Second switch thin film transistor 16 Driving thin film transistor 17 Anisotropic conductive film 18 Connection point 21 EC element signal line 22 Electrophoretic element signal line 23 Common scanning line 24 Common ground line 27 First One capacitive element 28 Second capacitive element

Claims (8)

An EC layer having a predetermined display area and exhibiting a change in the colored state based on an electrochromic (hereinafter referred to as “EC”) reaction, and a colored state accompanying the movement of the electrophoretic particles having the predetermined display area An electrophoretic layer exhibiting a change in the above, and an electro-optic display device configured by superimposing the EC layer on the viewing side,
The EC layer includes a first EC layer in which first EC elements that can be colored in the first primary color are arranged, and a second EC layer in which second EC elements that can be colored in the second primary color are arranged. And a third EC layer in which third EC elements that can be colored in the third primary color are arranged, and the first to third EC elements can each display a colorless transparent color, and An electro-optical display device, wherein the first EC element, the second EC element, and the third EC element are arranged so as not to overlap each other when viewed from the viewing side.   The first EC element, the second EC element, and the third EC element are arranged so as to be shifted from each other by ½ element or １ ／ element as viewed from the viewing side. The electro-optical display device described. An EC layer having a predetermined display area and exhibiting a change in the colored state based on an electrochromic (hereinafter referred to as “EC”) reaction, and a colored state accompanying the movement of the electrophoretic particles having the predetermined display area An electrophoretic layer exhibiting a change in the above, and an electro-optic display device configured by superimposing the EC layer on the viewing side,
The EC layer includes a first EC layer in which first EC elements that can be colored in the first primary color are arranged, and a second EC layer in which second EC elements that can be colored in the second primary color are arranged. And a third EC layer in which third EC elements that can be colored in the third primary color are arranged, and the first to third EC elements can each display a colorless transparent color, and An electro-optical display device, wherein two or more layers of the first EC element, the second EC element, and the third EC element are arranged so as to overlap each other when viewed from the viewing side. .   The electro-optical display device according to claim 1, wherein the first primary color is cyan, the second primary color is magenta, and the third primary color is yellow.   The electro-optical display device according to claim 1, wherein the first primary color is blue, the second primary color is green, and the third primary color is red.   6. The electro-optical display device according to claim 4, wherein the second EC layer is thicker than the first EC layer, and the third EC layer is thicker than the second EC layer.   The electro-optical display device according to claim 1, wherein the density of the display color is adjusted by a combination of a colored state / colorless and transparent state of a plurality of same-color EC elements in the specific region. The electro-optical display device according to claim 1, wherein a touch panel is formed on the EC layer.