JP2009265271A - Electro-optical display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optical display, surely synchronizing the display states of two displays with each other while avoiding complicatedness of circuit configuration. <P>SOLUTION: An electronic circuit layer 6 for driving an EC element 2 and an electrophoretic element 4 includes: a signal line for the EC element; a first switching thin film transistor 14 connected to the signal line for the EC element; a signal line for the electrophoretic element; a second switching thin film transistor 15 connected to the signal line for the electrophoretic element; a common scanning line connected to a control electrode of the first switching thin film transistor 14 and a control electrode of the second switching thin film transistor 15; and a driving thin film transistor 16 whose control electrode is connected to the second switching thin film transistor 15, wherein the driving thin film transistor 16 is connected to a pixel electrode 8 of the EC element 2, and the second switching thin film transistor 15 is connected to a pixel electrode 12 of the electrophoretic element 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an EC layer capable of displaying based on an electrochromic (hereinafter referred to as “EC”) reaction, and an electrophoretic layer capable of displaying based on electrophoretic charged particles (hereinafter referred to as “electrophoretic particles”). The electro-optical display device is configured by superimposing and.

  In recent years, research and development of display devices such as electronic paper and flexible displays having the same handling and visibility as paper media have been actively conducted. As a means for realizing such a display device, an electrophoretic display device that moves electrophoretic particles enclosed in a cell by an electric field and modulates a light reflection state by the electrophoretic particles has attracted attention. However, since the electrophoretic display device basically controls the distribution state of the electrophoretic particles by binary on / off of the applied voltage, the electrophoretic display device supports full-color display that requires at least three primary colors. Is generally considered difficult.

  Under such a background, Patent Document 1 discloses that an EC layer exhibiting a transparent region and a colored region (for example, a blue region) by an EC reaction based on voltage / current control is superposed on a lower portion of the EC layer. An electrophoretic layer having a first color region (for example, a red region) and a second color region (for example, a green region) different from the color of the colored region of the EC layer by electric field control, and red, green, and blue on the viewing side And the multicolor display of these mixed colors is described.

Patent Document 2 discloses an EC display in which an electrophoretic display element in which a microcapsule containing a pigment or a partition for separating the pigment is sandwiched between two electrodes is formed between the two electrodes. A color rewritable display device having a configuration in which elements are superposed 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. 10-161161 (FIG. 4) Japanese Patent Laying-Open No. 2004-286977 (FIG. 1)

  Although the above Patent Documents 1 and 2 describe the idea of superposing an electrophoretic display device and an EC display device, as a practical problem, (1) the individual pixels of the two display devices facing each other are Since the color for one pixel must be expressed together, the signals to the overlapping pixels must be surely synchronized. In addition, (2) since light incident on the EC display device is transmitted through the EC display device, reflected by the electrophoretic display device, and again transmitted through the EC display device, the light is visually recognized as display light. Building a complicated circuit configuration that prevents propagation leads to a decrease in reflectance of a display device configured by superposition.

  Accordingly, an object of the present invention is to reliably synchronize the display states of two display devices while avoiding the complexity of the circuit configuration.

The electro-optic display device of the present invention that can achieve the above object is
An EC layer comprising a plurality of EC elements sandwiching an EC material layer between the first pixel electrode and the second pixel electrode;
An electrophoretic layer comprising a plurality of electrophoretic elements sandwiching electrophoretic particles between a third pixel electrode and a fourth pixel electrode;
An electronic circuit layer for driving the EC element and the electrophoretic element;
In which the electronic circuit layer is
An EC element signal line for transmitting a display signal to the EC element;
A first switch thin film transistor having a first electrode, a second electrode, and a control electrode, wherein the first electrode is connected to the EC element signal line;
An electrophoretic element signal line for transmitting a display signal to the electrophoretic element;
A second thin film transistor for a switch having a first electrode, a second electrode, and a control electrode, wherein the first electrode is connected to the electrophoretic element signal line;
A common scanning line connected to a control electrode of the first switch thin film transistor and a control electrode of the second switch thin film transistor;
A driving thin film transistor having a first electrode, a second electrode, and a control electrode, wherein the control electrode is connected to the second electrode of the second switching thin film transistor;
The first electrode of the driving thin film transistor is grounded, the second electrode is connected to the second pixel electrode of the EC element, and the second electrode of the second switching thin film transistor is the first electrode of the electrophoretic element. It is connected to the three pixel electrodes.

  In the electro-optical display device, the first pixel electrode of the EC element is configured by one common electrode, the fourth pixel electrode of the electrophoretic element is configured by one common electrode, and the second pixel electrode of the EC element is configured. The pixel electrode and the third pixel electrode of the electrophoretic element may be opposed to each other, and the electronic circuit layer may be formed to be sandwiched between the EC layer and the electrophoretic layer.

  In the electro-optic display device, a common ground line is formed in parallel with the common scanning line, and a second electrode of the first switching thin film transistor is connected to the common ground line through a first capacitor element, A configuration in which the second electrode of the second switch thin film transistor is connected to the common ground line via a second capacitor element is preferably used.

  In the electro-optical display device, a configuration in which the first switch thin film transistor, the second switch thin film transistor, and the drive thin film transistor are formed of transparent thin film transistors is preferably used.

  In the electro-optic display device, the electrophoretic layer may be formed so as to be sandwiched between the EC layer and the electronic circuit layer.

  In the electro-optical display device, a configuration in which a semiconductor used for the first switching thin film transistor, the second switching thin film transistor, and the driving thin film transistor is an organic semiconductor is preferably used.

  In the electro-optical display device, a configuration in which the electronic circuit layer and the EC layer and / or the electronic circuit layer and the electrophoretic layer are connected via an anisotropic conductive film is preferably used.

  In the electro-optical display device, an embodiment in which the anisotropic conductive film is a transparent anisotropic conductive film is recommended.

  In the electro-optical display device, a configuration in which the EC layer is configured to be capable of color display with three colors of cyan, magenta, and yellow, or color display with three colors of red, blue, and green is preferably used. .

  In the electro-optical display device, a configuration in which a touch panel is formed on the viewing side is preferably used.

  In the present invention, “connection” means a state in which a signal can be propagated electrically. In addition to direct connection by wiring, indirect connection connected via a passive element such as a capacitor or a resistor. Is also included.

  In the present invention, since an electrophoretic layer suitable for displaying an achromatic color (gray scale) is disposed on the back side (opposite side to the viewing side) of the EC layer, the color elements are enriched and only the EC layer is used. An expressive full-color image with high gradation that cannot be expressed in color display can be displayed. Further, since each EC layer can display a colorless and transparent color, an achromatic image by the electrophoretic layer can be displayed more clearly.

  Furthermore, in the present invention, an electro-optic configured by superposing an EC layer having a plurality of EC elements, an electrophoretic layer having a plurality of electrophoretic elements, and an electronic circuit layer for driving the EC elements and the electrophoretic elements. In the display device, the thin film transistor for driving the EC element and the thin film transistor for driving the electrophoretic element are driven by a common scanning line, so that the display state of the two display devices can be reliably synchronized while avoiding the complexity of the circuit configuration. This contributes greatly to the practical application of electronic paper and flexible displays compatible with full-color display.

(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 of an electro-optic display device according to a first embodiment of the present invention. In FIG. 1, an electro-optic display device 1 includes an EC layer 3 including a plurality of EC elements 2, an electrophoretic layer 5 including a plurality of electrophoretic elements 4, and electrons for driving the EC elements 2 and the electrophoretic elements 4. The circuit layer 6 is overlapped. The EC layer 3 in the present embodiment is a light transmission type display device (or color filter), and the electrophoretic layer 5 is a light reflection type display device in the present embodiment. The viewing side of 1 is the EC layer 3 side.

2. EC element The EC element 2 is configured by sandwiching an EC material layer 9 between a first pixel electrode 7 and a second pixel electrode 8 that can be selected between a colored state and a colorless transparent state by an oxidation-reduction reaction. It is. Since at least one of the first pixel electrode 7 or the second pixel electrode 8 may have a fixed potential, it can be constituted by one common electrode. In the present embodiment, the first pixel electrode 7 is An example in which the common electrode is used will be described. Hereinafter, the first pixel electrode 7 is referred to as “common electrode 7”, and the second pixel electrode 8 is simply referred to as “pixel electrode 8”.

  Examples of the EC material layer 9 include organic materials such as anthraquinone dyes and styryl spiropyran dyes as red materials, aromatic amine dyes and viologen dyes as green materials, and viologen dyes and pyrazoline dyes as blue materials. EC dyes can be used as RGB three primary colors. Alternatively, 1,4-diacetylbenzene as a cyan material, dimethyl terephthalate as a magenta material, and diethyl 4,4'-biphenyldicarboxylate as a yellow material are each dissolved in 1-methyl-2-pyrrolidone. Can be used as In the case of being colorless and transparent, on the viewing side, the color reflected from the electrophoretic layer 5 as a base 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 2 may be one pixel, and the color density may be adjusted according to the number of EC elements 2 in a colored state within one pixel.

  Furthermore, the color density can also be controlled by adjusting the voltage application time per unit time for one EC element 2. 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 layer 3 functions as a light transmissive display device (or color filter), the common electrode 7 and the pixel electrode 8 must 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 layer 9 can be applied on the common electrode 7 by an inkjet method, for example. The EC material layer 9 may be a liquid material that can be filled in a cell having the spacer 10 as a side wall, but for convenience of handling and manufacturing, the EC material layer 9 has a shape without flowing out between the common electrode 7 and the pixel electrode 8. It is preferable to use a solid or semi-solid state capable of holding

  It is not always necessary to use three EC elements 2 to configure one pixel, and a unit of one pixel may be configured by two EC elements 2. If there are a large number of EC elements 2 used for one pixel, various colors can be produced by superimposing colors. However, the number of EC elements 2 allocated to one pixel increases, and the resolution decreases. It is preferable to select a one-pixel configuration.

3. Electrophoretic Layer In FIG. 1, the electrophoretic layer 5 includes a plurality of electrophoretic elements 4 configured by sandwiching a microcapsule 11 enclosing a dispersion liquid between a third pixel electrode 12 and a fourth pixel electrode 13. Is. Since at least one of the third pixel electrode 12 or the fourth pixel electrode 13 may have a fixed potential, it can be composed of one common electrode. In the present embodiment, the fourth pixel electrode 13 An example in which the common electrode is used will be described. Hereinafter, the fourth pixel electrode 13 is referred to as “common electrode 13”, and the third pixel electrode 12 is simply referred to as “pixel electrode 12”.

  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.

  The arrangement method of the electrophoretic elements 4 is not limited to a grid shape, and various arrangements such as a stripe shape and a honeycomb shape can be adopted. The arrangement method of the EC elements 2 can also take the same form according to this.

4). Electronic Circuit Layer As shown in FIG. 1, in the present embodiment, an electronic circuit layer 6 for driving the EC element 2 and the electrophoretic element 4 is sandwiched between the EC layer 3 and the electrophoretic layer 5. ing. 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. 2 is an electronic circuit diagram showing a connection relationship between the EC element 2 and the electrophoretic element 4 described above and the first switching thin film transistor 14, the second switching thin film transistor 15, and the driving thin film transistor 16. In FIG. 2, an EC element signal line 21 for transmitting a display signal to the EC element 2 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.

  More specifically, the EC element signal line 21 repeats three lines for cyan display, magenta display, and yellow display, or repeats three lines for red display, green display, and blue display. Is configured. If the three primary colors are used, it is possible to support full-color display, but this is not an essential component for implementing the present invention.

  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 FIGS. 1 and 2).

  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 FIGS. 1 and 2) of the EC element 2, and the common electrode 7 (FIG. 1, FIG. 2) of the EC element 2. 2) is connected to a power supply Vcom that provides a constant potential. When the common electrode 7 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 7 to become a predetermined potential is shortened. Further, if the common electrode 7 is not formed in the entire matrix structure but is formed for each line or each EC element 2, it is necessary to individually wire the power supply Vcom.

  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 2 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 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 2 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. 3 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 3 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 to connect the EC layer 3 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 8 of the EC element 2 can be easily connected. As a method of connection, first, an anisotropic conductive film 17 is sandwiched between the electronic circuit layer 6 and the EC layer 3, and conduction between the electronic circuit layer 6 and the EC layer 3 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 8 of the EC element 2 function as the EC element 2 if they are connected at least at one point. It is preferable that the number of contacts with the second pixel electrode 8 is larger. A transparent material such as ITO, which is a material of the pixel electrode 8, has a lower electrical conductivity than aluminum or copper. For this reason, when the number of connection points between the driving thin film transistor 16 of the electronic circuit layer 6 and the pixel electrode 8 of the EC element 2 is small, uneven coloring or display delay occurs in the pixel, but there are many contacts. Since the time until the entire pixel electrode 8 becomes equipotential can be shortened, it is possible to cope with the case where the display state is switched at high speed. Accordingly, it is desirable that the anisotropic conductive film 17 is energized in a linear region rather than 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 8.

  As described above, the structure on the viewer side of the electrophoretic layer 5 according to the first embodiment, for example, the EC layer 3 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 2 and the electrophoretic element 4 are arranged so as to overlap each other, and the color that can be observed from the viewing side is determined by the display color of the electrophoretic element 4 and the display color of the EC element 2. Therefore, the EC element 2 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 2 to be displayed, and the electrophoretic element signal connected to the electrophoretic element 4 facing the EC element 2. The line 22 is addressed with a predetermined voltage. In this state, preparation for simultaneously coloring the EC element 2 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 are in a conductive state, the pixel electrode 8 of the EC element 2 is at a predetermined potential, and the EC element 2 is in a desired color state.

  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 2 is controlled by one common scanning line 23. The coloration timing of the EC element 2 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.

(Embodiment 2)
In the first embodiment, the configuration in which the electronic circuit layer 6 is sandwiched between the EC layer 3 and the electrophoretic layer 5 has been described. However, if the common scanning line 23 can be arranged, the electronic circuit layer 6 is It may be formed in any layer. FIG. 4 is a schematic cross-sectional view of the electro-optic display device 1 according to the second embodiment of the present invention. As shown in FIG. 4, the electronic circuit layer 6 may be formed on the lower side of the electrophoretic layer 5, that is, on the side opposite to the EC layer 3. In this case, since the interval between the EC layer 3 and the electrophoretic layer 5 is narrowed, the parallax between the EC element 2 and the electrophoretic element 4 is reduced, and color unevenness, color blurring, and the like are reduced. However, in order to transmit a signal from the electronic circuit layer 6 to the EC element 2, it is necessary to provide a hole such as a via hole in the electrophoretic layer 5.

(Embodiment 3)
In Embodiments 1 and 2, the case where the EC layer 3 is on the viewing side has been described. However, if the electrophoretic layer 5 can be transparently displayed, the electrophoretic layer 5 may be formed on the viewing side. Good. As shown in FIG. 5, as the electrophoretic layer 5 capable of transparent display, a concave cell is formed, a partition wall electrode 31 is disposed on the side wall side of the cell, and the transparent electrophoretic liquid 32 and the colored electrophoresis are provided. A so-called in-plane type electrophoretic layer 5 in which the electrophoretic particles 33 are moved in the horizontal direction using the particles 33 can be used. According to this method, by attracting the electrophoretic particles 33 to the partition wall electrode 31, light can be transmitted through the lower electrode 34.

(Embodiment 4)
In the first to third embodiments, the semiconductors used for the first switch thin film transistor 14, the second switch thin film transistor 15, and the drive thin film transistor 16 can be formed of an organic semiconductor. An organic semiconductor can be formed on a transparent resin such as polyethylene terephthalate (PET) by printing, has characteristics of light weight, large area, and flexibility, and is suitably used for applications such as electronic paper. An example of an organic p-type semiconductor is pentacene. Pentacene is a low molecular weight compound having a structure in which five benzene rings are bonded. The principle of electron conduction is that π electrons existing in the double bond of the benzene ring move.

(Embodiment 5)
In the first to fourth 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.

  As described above, according to the electro-optic display device of the present invention, the electrophoretic layer suitable for displaying an achromatic color (gray scale) is disposed 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 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.

  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.

1 is a schematic cross-sectional view of an electro-optic display device according to a first embodiment of the present invention. 3 is an electronic circuit of the electro-optic display device according to the first exemplary embodiment of the present invention. 6 is another electronic circuit of the electro-optical display device according to the first exemplary embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of an electro-optic display device according to a second embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of an electrophoretic layer of an electro-optic display device according to a third 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 31 Partition electrode 32 Insulating liquid 33 Electrophoretic particle 34 Lower electrode

Claims (10)

An EC layer including a plurality of EC elements each having an electrochromic (hereinafter referred to as “EC”) material layer sandwiched between the first pixel electrode and the second pixel electrode;
An electrophoretic layer comprising a plurality of electrophoretic elements sandwiching electrophoretic particles between a third pixel electrode and a fourth pixel electrode;
An electronic circuit layer for driving the EC element and the electrophoretic element;
In which the electronic circuit layer is
An EC element signal line for transmitting a display signal to the EC element;
A first switch thin film transistor having a first electrode, a second electrode, and a control electrode, wherein the first electrode is connected to the EC element signal line;
An electrophoretic element signal line for transmitting a display signal to the electrophoretic element;
A second thin film transistor for a switch having a first electrode, a second electrode, and a control electrode, wherein the first electrode is connected to the electrophoretic element signal line;
A common scanning line connected to a control electrode of the first switch thin film transistor and a control electrode of the second switch thin film transistor;
A driving thin film transistor having a first electrode, a second electrode, and a control electrode, wherein the control electrode is connected to the second electrode of the second switching thin film transistor;
The first electrode of the driving thin film transistor is grounded, the second electrode is connected to the second pixel electrode of the EC element, and the second electrode of the second switching thin film transistor is the first electrode of the electrophoretic element. An electro-optic display device connected to three pixel electrodes.   The first pixel electrode of the EC element is composed of one common electrode, the fourth pixel electrode of the electrophoretic element is composed of one common electrode, and the second pixel electrode of the EC element and the electrophoretic element The electro-optical display device according to claim 1, wherein the third pixel electrode is opposed to the electronic circuit layer, and the electronic circuit layer is formed between the EC layer and the electrophoretic layer.   A common ground line is formed in parallel with the common scanning line, and a second electrode of the first switch thin film transistor is connected to the common ground line via a first capacitor element, and the second switch thin film transistor The electro-optical display device according to claim 2, wherein the second electrode is connected to the common ground line via a second capacitive element.   4. The electro-optical display device according to claim 2, wherein the first switch thin film transistor, the second switch thin film transistor, and the drive thin film transistor are formed of transparent thin film transistors. 5.   The electro-optical display device according to claim 1, wherein the electrophoretic layer is formed so as to be sandwiched between the EC layer and the electronic circuit layer.   The electro-optic display device according to claim 1, wherein a semiconductor used for the first switching thin film transistor, the second switching thin film transistor, and the driving thin film transistor is an organic semiconductor.   The electro-optical display device according to claim 1, wherein the electronic circuit layer and the EC layer and / or the electronic circuit layer and the electrophoretic layer are connected via an anisotropic conductive film.   The electro-optic display device according to claim 7, wherein the anisotropic conductive film is a transparent anisotropic conductive film.   The EC layer is configured to be capable of color display with three colors of cyan, magenta, and yellow, or color display with three colors of red, blue, and green. Electro-optic display device. The electro-optical display device according to claim 1, wherein a touch panel is formed on the viewing side.