JP2013221965A - Electro-optic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electro-optic device that displays high-quality images.SOLUTION: A pixel 20 includes a first sub-pixel 211, a second sub-pixel 212 and a third sub-pixel 213. Each sub-pixel 21 includes a light-emitting element LED and an electrophoretic element EPD. An electro-optic device 150 includes a first substrate 80 and a second substrate 90, in which the electrophoretic element EPD comprises a pixel electrode 22 formed on the first substrate 80, a common electrode 23 formed on the second substrate 90, and an electrophoretic material 24 disposed between the pixel electrode 22 and the common electrode 23; the light-emitting element LED is formed on the first substrate 80; and the pixel electrode 22 does not overlap the light-emitting element LED in a plan view. In a monochromatic display mode, the electrophoretic element EPD is used, and in a color display mode, the light-emitting element LED is actuated to emit light. The electro-optic device functions as an electrophoretic display device in a monochromatic display mode and can display a beautiful color image without using a color filter.

Description

  The present invention relates to the technical field of electro-optical devices.

  As an example of an electro-optical device, an electrophoretic display device is known as described in Patent Document 1. In an electrophoretic display device, an image is formed on a display unit by moving a charged black particle or white particle or other electrophoretic particle by applying a voltage between a pixel electrode and a common electrode facing each other across a dispersion liquid. ing. Specifically, for example, when black particles are negatively charged, white particles are positively charged, and a common electrode is provided on the display surface side, in a pixel displaying white, the potential of the pixel electrode is higher than the potential of the common electrode. The white particles were collected on the common electrode side while maintaining a high state. On the other hand, in the pixel displaying black, the pixel electrode potential is kept lower than the common electrode potential, and black particles are collected on the common electrode side.

  In order to perform color display with such an electrophoretic display device, red, green and blue color filters are overlaid in accordance with the pixels of the electrophoretic display device. For example, if you want to display red, the pixel corresponding to the red color filter (red pixel) collects white particles on the common electrode side, and the pixel corresponding to the green and blue color filter (green pixel and blue pixel) Black particles were collected on the common electrode side. In this way, in the red pixel, the incident light is reflected by the white particles through the red color filter, while in the green pixel and the blue pixel, the incident light is absorbed by the black particles. Was realized. For example, when white display is desired, red particles, green pixels, and blue pixels collect white particles on the common electrode side.

JP 2009-145873 A

However, the conventional electrophoretic display device has a problem that the white display is dull in gray. Ideally, the white display should be pure white, but in reality, the white display was grayish white even when the white display was performed, and the reflectance of outside light was only about 46% during the white display. If the outside light is strong, such a low reflectance is not a big problem, but it is difficult to recognize the display contents in a dark place where the outside light is weak. On the other hand, since the electrophoretic display device is used for an electronic book or the like, it has been desired to use it in a dim place such as a bedroom or an airplane. That is, there is a problem that it is difficult to obtain high image quality in the conventional electrophoretic display device, and it is difficult to perform display suitable for the usage environment.
Further, the conventional electrophoretic display device has a problem that only two colors such as black and white can be displayed unless a color filter is used.
On the other hand, when the color filter is used, there is a problem that the saturation of the displayed color is low and the white display is extremely dark. The low saturation is explained as follows. For example, in the case of displaying red, since the green pixel and the blue pixel are displayed in black, the ratio of red pixels is 1/3. Further, the incident light to the red pixel passes through the red color filter, and the amount of light is reduced to 1/3 or less. In addition, the reflectance of white particles is as low as about 46%. Accordingly, only a maximum of 33.3% × 33.3% × 46% = 5% of the total amount of light incident on the red, green, and blue pixels is used for red display. For this reason, the saturation is lowered, and for the same reason, the reflectance of white display is as low as 33.3% × 46% = 15%, and the white display is extremely dark.
In other words, the conventional electrophoretic display device has a problem that it is difficult to obtain high image quality. Furthermore, multicolor display is difficult, and the electrophoretic display device for color display has a problem that the image quality is extremely low.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 An electro-optical device according to this application example includes a pixel, the pixel includes a first subpixel and a second subpixel, and the first subpixel mainly emits light of a first color. A first light emitting element and an electrophoretic element are provided, and the second sub-pixel is provided with a second light emitting element that mainly emits a second color different from the first color, and an electrophoretic element. The electrophoretic element is provided between the pixel electrode formed on the first substrate, the common electrode formed on the second substrate, and the pixel electrode and the common electrode. The first light emitting element and the second light emitting element are formed on the first substrate, and the pixel electrode of the first subpixel does not overlap the first light emitting element in plan view. The pixel electrode in the second subpixel overlaps the second light emitting element in plan view. It is characterized by not.
According to this configuration, when the electrophoretic element performs a bright display, the light emitting element can emit light. The bright display of the electrophoretic element reflects external light, and the light emitting element emits additional light, so that the bright display becomes extremely bright. In addition, even when the outside light is weak, it is easy to distinguish between bright display and dark display, and even if the electro-optical device is used in a dim place, an easy-to-view display is made. Furthermore, since the first color and the second color are different, multicolor display is possible without using a color filter. Since each subpixel includes a self-luminous element, high-saturation and beautiful multicolor display is possible. In other words, it is possible to obtain high image quality with a multicolor electrophoretic display device, and it is possible to perform display suitable for the use environment.

Application Example 2 In the electro-optical device according to the application example, the pixel further includes a third subpixel, and the third subpixel mainly includes a third color different from the first color and the second color. A third light emitting element that emits light and an electrophoretic element are provided, the third light emitting element is formed on the first substrate, and the pixel electrode in the third subpixel does not overlap with the third light emitting element in plan view. Things are preferable.
According to this configuration, the first color, the second color, and the third color can be made the three primary colors of light. That is, an electro-optical device capable of color display can be realized without using a color filter.

Application Example 3 In the electro-optical device according to the application example, it is preferable that the electrophoretic material includes first particles and second particles, the first particles are charged, and the second particles are not charged. .
According to this configuration, the first particles are electrophoresed and collected at a specific location, while the second particles are diffused. Therefore, the electrophoretic element can switch between bright and dark display. Furthermore, since the diffused second particles scatter the light (emitted light) emitted from the light emitting element, the emitted light is efficiently extracted outside the electro-optical device. That is, when the electrophoretic element performs bright display, the bright display can be brightened and multicolor display and color display can be realized.

(Application Example 4) In the electro-optical device according to Application Example 2 or 3, the first light emitting element is a light emitting diode having a first light emitting layer, and the second light emitting element is a light emitting diode having a second light emitting layer. The third light emitting element is preferably a light emitting diode having a third light emitting layer.
According to this configuration, a normal thin film semiconductor manufacturing process can be applied to the manufacture of an electro-optical device. Further, since the light emitting element becomes a thin film element, the thin film element and the electrophoretic element can be easily combined. That is, the electro-optical device can be easily manufactured.

Application Example 5 The electro-optical device according to this application example is an electro-optical device in which an electrophoretic element and a light-emitting element are provided in a subpixel, and the electrophoretic element is used when the light-emitting element does not emit light. Bright display and dark display can be switched, and the light-emitting element can switch between light emission and non-light emission when the electrophoretic element performs bright display.
According to this configuration, in a monochromematic display (for example, black and white display) use environment, the light emitting element is made non-light-emitting and display is performed by switching the display of the electrophoretic element. In a multicolor display or color display use environment, each subpixel is displayed. Light emission and non-light emission can be controlled. Accordingly, it is possible to achieve both monochrome display by the electrophoretic element and color display by the light emitting element. Further, in a dim place where the external light is weak, the bright display pixels of the electrophoretic element can emit light from the light emitting elements arranged in the respective sub-pixels so that a bright bright display can be obtained. That is, in a dark usage environment, a light emitting element is caused to emit light by a pixel sub-pixel (bright display sub-pixel) in which the electrophoretic element is brightly displayed, and a pixel sub-pixel (dark display sub-pixel) in which dark display is performed. Then, the light emitting element can be made to emit no light. In other words, it is possible to obtain high image quality in a color display electrophoretic display device, and it is possible to suppress energy consumption in a bright use environment, and a contrast ratio between light and dark is large in a dark use environment. Thus, an electro-optical device that performs clear display can be obtained.

Application Example 6 In the electro-optical device according to Application Example 5, when the light emitting element emits light when the electrophoretic element performs bright display, it is preferable that part of the emitted light is emitted from the subpixel.
According to this configuration, since at least a part of the emitted light is emitted from the bright display subpixel, multicolor display using the light emitting element can be realized. Furthermore, since the emitted light and the reflected light of the outside light are emitted from the bright display subpixel, the bright display subpixel can be brightened. In other words, it is possible to realize an electro-optical device that realizes multicolor display and has a large contrast ratio between light and dark and performs clear display.

Application Example 7 In the electro-optical device according to Application Example 3, when the first light-emitting element emits light when the first particles are collected in the vicinity of the pixel electrode, the emitted light is scattered by the second particles and emitted. It is preferable that a part of the emitted light is emitted from the first subpixel.
According to this configuration, since the emitted light is scattered by the second particles diffused almost uniformly between the first substrate and the second substrate, a part of the emitted light is emitted uniformly from the bright display subpixel. Is done. Accordingly, multi-color display can be performed, and in addition, the bright display sub-pixel can be brightened, and the contrast ratio between light and dark can be increased, and an electro-optical device that performs clear display can be obtained.

Application Example 8 The electro-optical device according to this application example includes a sub-pixel, and the sub-pixel includes a first power supply line and a second power supply line, and the sub-pixel includes a selection transistor, a drive transistor, and a pixel electrode. An anode electrode, a cathode electrode, a light emitting layer provided between the anode electrode and the cathode electrode, the pixel electrode, the drain of the selection transistor, and the gate of the driving transistor are electrically connected, and the first power line and the second power source A drive transistor, an anode electrode, and a cathode electrode are arranged between the first power supply line and the potential difference between the first power supply line and the second power supply line can be set to a potential difference between the light emitting layer and a non-light emitting potential. It can be supplied to the line and the second power supply line, respectively.
According to this configuration, when a potential that is a potential difference at which the light emitting layer does not emit light is supplied to the first power supply line and the second power supply line, the light emitting element is non-light emitting, and the potential that is a potential difference at which the light emitting layer can emit light. Is supplied to the first power supply line and the second power supply line, respectively, the light emitting element can emit light. Further, regardless of whether the potential difference between the first power supply line and the second power supply line is a value that causes the light emitting element to emit no light or a value that enables the light emitting element to emit light, the bright display and the dark display of the electrophoretic element are displayed. And can be switched. In other words, the light emitting element and the electrophoretic element can be controlled independently to realize multicolor display, and a high contrast ratio between light and dark and an electro-optical device that performs clear display.

Application Example 9 In the electro-optical device according to Application Example 8, the signal line and the scanning line are provided, the subpixel is arranged corresponding to the intersection of the signal line and the scanning line, and the source of the selection transistor and the signal line are arranged. Are electrically connected, and the gate of the selection transistor and the scanning line are preferably electrically connected.
According to this configuration, since the plurality of subpixels can be controlled independently, an image can be displayed on the electro-optical device.

The perspective view of an electronic device. FIG. 6 is a plan view illustrating one pixel of the electro-optical device. 2A and 2B are diagrams illustrating one subpixel of the electro-optical device, where FIG. 3A is a circuit diagram, and FIG. Sectional drawing explaining the operation state of an electro-optical apparatus. It is a figure explaining the bright display subpixel in a monochromematic mode, (a) is a circuit diagram, (b) is sectional drawing. It is a figure explaining the dark display subpixel in a monochromematic mode, (a) is a circuit diagram, (b) is sectional drawing. It is a figure explaining the bright display subpixel in a color mode, (a) is a circuit diagram, (b) is sectional drawing. It is a figure explaining the dark display subpixel in a color mode, (a) is a circuit diagram, (b) is sectional drawing. The perspective view which shows the structure of electronic paper. The perspective view which shows the structure of an electronic notebook. 6A and 6B are diagrams illustrating a bright display subpixel in a monochrome mode of the electro-optical device according to the second embodiment, where FIG. 4A and 4B are diagrams illustrating dark display subpixels in a monochrome mode of the electro-optical device according to the second embodiment, where FIG. 5A is a circuit diagram, and FIG. 6A and 6B are diagrams illustrating a bright display subpixel in a color mode of the electro-optical device according to the second embodiment, where FIG. 6A and 6B are diagrams illustrating dark display subpixels in a color mode of the electro-optical device according to the second embodiment, in which FIG. FIG. 9 is a plan view for explaining a part of a display area of an electro-optical device according to Modification 1; FIG. 9 is a plan view illustrating one pixel of an electro-optical device according to Modification 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each layer and each member is made different from the actual scale so that each layer and each member can be recognized.

(Embodiment 1)
"Outline of electronic equipment"
First, an outline of the electronic apparatus and the electro-optical device according to the first embodiment will be described with reference to FIG.

  FIG. 1 is a perspective view of an electronic apparatus according to this embodiment. As shown in FIG. 1, an electronic apparatus 100 according to the present invention includes an electro-optical device 150 and an interface for operating the electronic apparatus 100. Specifically, the interface is the operation unit 120 and includes a switch and the like. The electro-optical device 150 is a display module having the display area 10. In the display area 10, a plurality of pixels 20 (see FIG. 2) are regularly arranged in a matrix, and one pixel 20 includes a plurality of sub-pixels 21 (see FIG. 2). A desired image is displayed in the display area 10 by controlling these subpixels electrically and independently.

  The electronic device 100 includes a monochrome mode used for monochrome display (typically monochrome display), a color mode mainly used for multi-color display (typically color display), and the brightness of external light. And an automatic mode that automatically switches between monochrome mode and color mode. The color mode can also be used for monochrome display in dark places. The user selects these modes via the operation unit 120. In the monochromatic mode, the electro-optical device 150 is used as an electrophoretic display device, and at least bright display and dark display are controlled by each sub-pixel 21 to be a reflective display. On the other hand, in the color mode, the electro-optical device 150 becomes an electrophoretic display device / self-luminous element type display device, and light emission and non-light emission are controlled for each sub-pixel 21 to realize color display. The sub-pixel 21 (dark display sub-pixel) that forms a dark display pixel (dark display pixel) in the color mode performs dark display as an electrophoretic display device and non-light-emitting display or weak light emission as a self-light-emitting element type display device. Display. On the other hand, the sub-pixel 21 (bright display sub-pixel) that forms a bright display pixel (bright display pixel) in the color mode displays a bright display as an electrophoretic display device and a strong light-emitting display as a self-emitting element type display device. To do.

"Pixel configuration"
FIG. 2 is a plan view illustrating one pixel of the electro-optical device. Next, the planar structure of the pixel 20 will be described with reference to FIG. FIG. 2 shows the planar shape of one pixel 20. The pixel 20 includes at least a first subpixel 211 and a second subpixel 212, and further includes a third subpixel 213 in this embodiment. Each sub-pixel 21 is approximately the same size and occupies approximately 1/3 of the pixel. The first subpixel 211 is provided with a first light emitting element LED1 that mainly emits light of a first color and an electrophoretic element EPD (see FIG. 3), and the second subpixel 212 has a first color. A second light emitting element LED2 that mainly emits a second color different from that of the electrophoretic element EPD and an electrophoretic element EPD, and the third subpixel has a third color different from the first color and the second color. A third light emitting element LED3 that mainly emits light and an electrophoretic element EPD are provided. The first color, the second color, and the third color are different from each other, and in the present embodiment, the three primary colors of light correspond to these. Specifically, the first color is red, the second color is green, and the third color is blue. Therefore, the first light emitting element LED1 mainly emits red light, and its spectrum has a maximum intensity at a wavelength of about 650 nm. The second light emitting element LED2 mainly emits green light, and its spectrum has a maximum intensity at a wavelength of about 550 nm. Further, the third light emitting element LED3 mainly emits blue light, and its spectrum has a maximum intensity at a wavelength of about 485 nm. In addition, when it is not necessary to particularly distinguish the first subpixel 211, the second subpixel 212, and the third subpixel 213, these are collectively referred to as the subpixel 21. Similarly, when it is not necessary to distinguish the first light emitting element LED1, the second light emitting element LED2, and the third light emitting element LED3, they are collectively referred to as a light emitting element LED. The light emitted from the light emitting element LED is referred to as emission light.

  The electro-optical device 150 includes a first substrate 80 (see FIG. 3) and a second substrate 90 (see FIG. 3), and the first light emitting element LED1, the second light emitting element LED2, and the third light emitting element LED3 are the first substrate. 80. The electrophoretic element EPD is disposed between the pixel electrode 22 formed on the first substrate 80, the common electrode 23 (see FIG. 3) formed on the second substrate 90, and the pixel electrode 22 and the common electrode 23. Electrophoretic material 24 (see FIG. 3). That is, the electrophoretic element EPD formed in each subpixel 21 includes a pixel electrode 22 for each subpixel 21, and the pixel electrode 22 in the first subpixel 211 overlaps the first light emitting element LED1 in plan view. In addition, the pixel electrode 22 in the second subpixel 212 does not overlap with the second light emitting element LED2 in plan view, and the pixel electrode 22 in the third subpixel 213 in plan view with the third light emitting element LED3. There is no overlap.

  In this way, the pixel electrode 22 does not overlap the light emitting element LED in a plan view, but surrounds the light emitting element LED in a spaced manner. In the present embodiment, the light emitting surface of the light emitting element LED is the anode electrode A (see FIG. 3b). That is, the pixel electrode 22 is formed so as to surround the anode electrode A. The light emitting element LED is disposed at substantially the center of the sub-pixel 21, and the pixel electrode 22 surrounds the light emitting element LED so as to be equal vertically or horizontally. Although the principle will be described in detail later, this is because light emitted from the light emitting element LED is scattered by the second particles 242 (see FIG. 3) and taken out from the electro-optical device 150. This is because the emitted light can be efficiently extracted without waste regardless of the state of the adjacent subpixel, and the uniformity of the color tone in the subpixel can be enhanced during bright display. However, it is not an essential condition that the pixel electrode 22 surrounds the light emitting element LED, and the pixel electrode 22 may not surround the light emitting element LED for convenience of layout. Further, the light emitting element LED is not necessarily arranged at the center of the subpixel 21.

  The relationship between the light emitting element LED and the pixel electrode 22 is that they do not overlap in plan view, the light emitting surface and the pixel electrode 22 form substantially the same plane, and the light emitting element LED and the pixel electrode 22 are on the plane. What is necessary is just to be spaced apart. By doing so, the emitted light emitted from the light emitting element LED is not blocked by the electrophoretic element EPD, and the emitted light is efficiently extracted outside the electro-optical device 150. In addition, the shape of the pixel electrode 22 and the light emitting element LED in a plan view is not limited to a square, and may take various shapes. For example, the pixel electrode 22 may be hexagonal. In addition, the light emitting element LED is also oval or oval such as an oval, oval or ellipse, or a rounded quadrangle consisting of two parallel lines and two semicircles as in an athletic field, or a hexagon. It may be a polygon. It is preferable that the light emitting element LED is located substantially at the center of the pixel electrode 22, which means that the center of gravity position of the light emitting element LED in plan view and the position of the center of gravity of the pixel electrode 22 in plan view are substantially the same. It is.

  In the monochromatic mode, since the electro-optical device 150 is used as an electrophoretic display device, each subpixel 21 is displayed bright (white display) and dark (black display) with the light emitting element LED not emitting light. And can be switched. As a result, the actual resolution in the monochrome mode is three times the resolution in the color mode. In the dark mode pixel in the color mode, all the subpixels 21 constituting the dark display pixel (in the present embodiment, three of the first subpixel 211, the second subpixel 212, and the third subpixel 213). ), The electrophoretic element EPD performs a dark display, and the light emitting element LED does not emit light in principle. On the other hand, in the color mode, in the bright display pixel, all the subpixels 21 constituting the bright display pixel (in this embodiment, the first subpixel 211, the second subpixel 212, and the third subpixel 213 3), the electrophoretic element EPD performs a bright display, and the light emitting element LED (in this embodiment, the first light emitting element LED1, the second light emitting element LED2, and the third light emitting element LED3) emit light. In the pixel 20 that displays a specific color in the color mode, out of all the subpixels 21 constituting the pixel 20, the subpixel 21 that needs to emit light to constitute the color is electrically The electrophoretic element EPD is brightly displayed and the light emitting element LED is caused to emit light. On the other hand, in the sub-pixel 21 that should not emit light to constitute the color, the electrophoretic element EPD is darkly displayed and the light-emitting element LED is in principle non-light-emitting. For example, in the case of the pixel 20 that wants to display yellow, yellow is obtained by additive mixing of red and green. Therefore, the first subpixel 211 that emits red light and the second subpixel 212 that emits green light are electrically connected. The electrophoretic element EPD is displayed brightly, the first light emitting element LED1 and the second light emitting element LED2 emit light, and the third subpixel 213 emits blue light. In principle, the LED 3 is not light-emitting.

"Sub-pixel configuration"
3A and 3B are diagrams for explaining one subpixel of the electro-optical device according to the present embodiment. FIG. 3A is a circuit diagram, and FIG. 3B is a cross-sectional view. Next, the configuration of the sub-pixel 21 will be described with reference to FIG.

  A plurality of signal lines 40 and scanning lines 30 are wired vertically and horizontally in the display area 10 of the electro-optical device 150, and the sub-pixel 21 is provided at each intersection of the signal lines 40 and the scanning lines 30. Accordingly, the sub-pixels 21 are arranged in a matrix in the display area 10. Specifically, the sub-pixels in the i-th row and j-th column are located at the intersections of the i-th scanning line 30 and the j-th signal line 40. 21 is arranged. Since the i-th scanning line 30 and the j-th signal line 40 specify the sub-pixel 21 in the i-th row and j-th column, the plurality of sub-pixels 21 are controlled independently, and are desired by the electro-optical device 150. Is displayed.

  As shown in FIG. 3A, a first power supply line 41 and a second power supply line 31 are wired to the subpixel 21, and a common electrode 23 is provided. The subpixel 21 is formed with an electrophoretic element EPD and a light emitting element LED. The electrophoretic element EPD includes a pixel electrode 22, a common electrode 23, and an electrophoretic material 24 sandwiched between the pixel electrode 22 and the common electrode 23. On the other hand, the light emitting element LED includes an anode electrode A, a cathode electrode C, and a light emitting layer 25 (see FIG. 3B) sandwiched between the anode electrode A and the cathode electrode C. The subpixel 21 further includes a selection transistor ST, a driving transistor DT, and a capacitive element Cp. In this embodiment, the selection transistor ST is composed of an N-type thin film transistor, and the drive transistor DT is composed of a P-type thin film transistor.

  The source of the selection transistor ST is electrically connected to the signal line 40, the gate of the selection transistor ST is electrically connected to the scanning line 30, and the drain of the selection transistor ST is the gate of the driving transistor DT, the pixel electrode 22, and the capacitor element. It is electrically connected to one electrode of Cp. The other electrode of the capacitive element Cp is electrically connected to the common electrode 23. The capacitive element Cp is made up of a pair of electrodes arranged opposite to each other via a dielectric film, and sandwiches the dielectric film between one electrode and the other electrode (see FIG. 3B). The capacitive element Cp can maintain the image signal for a certain period. The driving transistor DT, the anode electrode A, and the cathode electrode C are disposed between the first power supply line 41 and the second power supply line 31. Specifically, the source of the driving transistor DT is electrically connected to the first power supply line 41, and the gate of the driving transistor DT is electrically connected to the drain of the selection transistor ST, the pixel electrode 22, and one electrode of the capacitor element Cp. The drain of the driving transistor DT is electrically connected to the anode electrode A of the light emitting element LED. The cathode electrode C of the light emitting element LED is electrically connected to the second power supply line 31. Note that the source and drain of a physically strict transistor is a source having a lower potential compared to the source in the N type, and a source having a higher potential compared to the source in the P type. Accordingly, although the source and the drain are interchanged depending on the operating conditions of the transistor, in this specification, for the sake of easy understanding, one is named as the source and the other is named as the drain. In FIG. 3A, these are represented by s and d. In addition, the term “terminal 1 and terminal 2 are electrically connected” refers to the case where terminal 1 and terminal 2 are connected via a resistance element or switching element in addition to the case where terminal 1 and terminal 2 are directly connected by wiring. Including. That is, even if the potential at the terminal 1 and the potential at the terminal 2 are slightly different, the terminal 1 and the terminal 2 are electrically connected if they have the same meaning on the circuit. For example, in FIG. 3A, the anode electrode A is electrically connected to the first power supply line 41. Actually, the drive transistor DT is interposed between the anode electrode A and the first power supply line 41. However, when the drive transistor DT is in a strong ON state (the drain conductance of the drive transistor DT is the conductance of the light emitting element LED). In view of the circuit meaning that the potential of the anode electrode A is substantially equal to the potential of the first power supply line 41, the anode electrode A and the first power supply line 41 are It can be said that they are electrically connected.

  In FIG. 3A, the first power supply line 41 is wired in the vertical direction like the signal line 40, and the second power supply line 31 is wired in the horizontal direction like the scanning line 30, but the wiring configuration is this. Not limited to. Since the first power supply line 41 and the second power supply line 31 have the same potential with respect to the plurality of subpixels 21, the first power supply line 41 or the second power supply line 31 is connected to the plurality of subpixels 21. You may share. For example, a single first power supply line 41 is shared by the subpixel 21 in the jth column and the subpixel 21 in the j + 1th column, and a single first power supply line 41 is arranged for the two signal lines 40. You may do it. Similarly, the i-th row sub-pixel 21 and the i + 1-th row sub-pixel 21 share one second power supply line 31, and two rows of scanning lines 30 have one second power supply line 31. It may be arranged. Furthermore, the second power supply line 31 may be wired in the vertical direction, and the first power supply line 41 may be wired in the horizontal direction. Further, both power supply lines may be wired in the vertical direction, or both power supply lines may be wired in the horizontal direction.

  Next, the cross-sectional structure of the electro-optical device 150 will be described with reference to FIG. The electro-optical device 150 includes a first substrate 80, a second substrate 90, and the electrophoretic material 24. The user views the electro-optical device 150 from the second substrate 90 side. On the first substrate 80, the pixel electrode 22 is formed for each subpixel 21, and the common electrode 23 is formed on almost the entire surface of the second substrate 90. The electrophoretic material 24 is sandwiched between the pixel electrode 22 and the common electrode 23 (that is, between the first substrate 80 and the second substrate 90). The light emitting element LED is formed on the first substrate 80, and the pixel electrode 22 and the light emitting surface of the light emitting element LED (the surface of the light emitting element LED located on the second substrate 90 side, in this embodiment, the anode electrode A) are on the same layer. Is formed. The light emitting layer 25 is sandwiched between the anode electrode A and the cathode electrode C, is an organic semiconductor film that emits light in the first color in the first light emitting element LED1, and emits light in the second color in the second light emitting element LED2. The organic semiconductor film is an organic semiconductor film that emits light in the third color in the third light emitting element LED3. The anode electrode A is formed of the same material (indium tin oxide) on the same layer (second interlayer insulating film) as the pixel electrode 22. The second interlayer insulating film is made of acrylic resin, and forms a bank for the light emitting layer 25 on the outer periphery of the light emitting element LED. Therefore, precisely, the pixel electrode 22 is formed on the second interlayer insulating film, the anode electrode A is formed on the light emitting layer 25, and the light emitting layer 25 and the second interlayer insulating film are substantially the same layer. Yes. The cathode electrode C is formed of the same material (aluminum alloy) on the same layer (first interlayer insulating film) as the signal line 40 and the first power supply line 41. Thus, since the light emitting element LED is a thin film element, the light emitting element LED and the electrophoretic element EPD are easily combined, and the electro-optical device 150 is easily manufactured. The first interlayer insulating film is formed of a silicon oxide film. The second power supply line 31, the other electrode of the capacitive element Cp, and the scanning line 30 are formed of the same material (aluminum alloy) on the same layer (gate insulating film). The gate insulating film is formed of a silicon oxide film and also serves as a dielectric film of the capacitive element Cp. The semiconductor film (source and drain and channel forming region sandwiched between them) of the selection transistor ST and the drive transistor DT and one electrode of the capacitive element Cp are a polycrystalline semiconductor film through a base insulating film (not shown). The first substrate 80 is formed. In this embodiment, an upper gate type thin film transistor is employed for both the selection transistor ST and the driving transistor DT, but these may be a lower gate type thin film transistor. Such a structure is easily realized by applying a normal thin film semiconductor manufacturing process.

  The electrophoretic material 24 includes first particles 241 and second particles 242, where the first particles 241 are charged and the second particles 242 are not charged. The first particles 241 have a color tone with low light reflectance and contribute to dark display. As an example, the first particles 241 are black, and are positively charged in this embodiment. The second particles 242 have a color tone with high light reflectance and contribute to bright display. As an example, the second particles 242 are white, and in this embodiment, no positive charging process is performed, and the second particles 242 are electrically neutral.

"Operating state"
FIG. 4 is a cross-sectional view for explaining the operating state of the electro-optical device according to this embodiment. Next, the relationship between the operation of the electro-optical device 150 and the use mode will be described with reference to FIG. As described above, the electro-optical device 150 has a monochrome mode and a color mode, and the display state can be switched between bright display and dark display. The bright display is a display in which the user sees the scattered light due to the second particles 242, and the dark display is a display in which the user sees the color of the first particles 241. In the bright display in the monochrome mode, the external light is scattered by the second particles 242, and in the bright display in the color mode, the external light and the emitted light are scattered by the second particles 242. 4 (a) shows a bright display state in the monochrome mode, FIG. 4 (b) shows a dark display state in the monochrome mode, and FIG. 4 (c) shows a bright display state in the color mode. FIG. 4D shows a dark display state in the color mode.

  In the electro-optical device 150, the electrophoretic element EPD can switch between bright display and dark display when the light emitting element LED does not emit light. Further, when the electrophoretic element EPD performs bright display, the light emitting element LED can switch between light emission and non-light emission. FIG. 4 illustrates these relationships. The monochromatic mode shown in FIGS. 4 (a) and 4 (b) is that the outside light is bright or the bright display reflectivity is high enough to use the electro-optical device 150, and the light emitting element LED is used. This mode is used when it is not necessary to emit light. In the monochromatic mode, since the light emitting element LED does not emit light, the electro-optical device 150 can be driven for a long time even with a battery with low energy consumption and a small capacity. The color modes shown in FIG. 4C and FIG. 4D are used when performing color display, when the external light is dark, or when the bright display reflectance is low when the electro-optical device 150 is used. Thus, the mode used when the light emitting element LED emits light provides a high-quality display. In the color mode, the light emitting element LED is caused to emit light by the sub-pixel 21 corresponding to the displayed color, so that beautiful multicolor display is possible. In addition, when used in a dark place, the light emitting element LED emits light in the sub-pixel 21 constituting the bright display pixel, so that a display with a high contrast ratio is possible, and the electro-optical device 150 can be comfortably used even in the dark place. I can do it.

  As shown in FIG. 4A, in the bright display subpixel in the monochrome mode, the charged first particles 241 are collected in the vicinity of the pixel electrode 22 in a state where the light emitting element LED is not emitting light. In the present embodiment, since the first particles 241 are positively charged, the potential of the pixel electrode 22 is made lower than the potential of the common electrode 23 and the first particles 241 are collected in the vicinity of the pixel electrode 22. Since the uncharged second particles 242 are uniformly dispersed between the first substrate 80 and the second substrate 90, the user sees the reflected light of the external light from the second particles 242.

  As shown in FIG. 4B, in the dark display subpixel in the monochrome mode, the charged first particles 241 are collected in the vicinity of the common electrode 23 in a state where the light emitting element LED is not emitting light. In this embodiment, since the first particles 241 are positively charged, the potential of the common electrode 23 is made lower than the potential of the pixel electrode 22, and the first particles 241 are collected in the vicinity of the common electrode 23. As a result, the user sees the first particles 241.

  As shown in FIG. 4C, in the bright display subpixel in the color mode, the charged first particles 241 are collected in the vicinity of the pixel electrode 22 in a state where the light emitting element LED emits light. Since the first particles 241 are positively charged, the potential of the pixel electrode 22 is made lower than the potential of the common electrode 23 to collect the first particles 241 in the vicinity of the pixel electrode 22 as before. Since the pixel electrode 22 is separated from the light emitting element LED in a plan view and does not overlap, various potentials are set so that the first particles 241 do not collect on the light emitting element LED. When the light emitting element LED emits light while the electrophoretic element EPD is in a bright display state, part of the emitted light is emitted from the bright display subpixel. Since the first particles 241 are collected in the vicinity of the pixel electrode 22, when the light emitting element LED emits light, the emitted light is uniformly distributed between the first substrate 80 and the second substrate 90. This is because a part of the emitted light (scattered light) scattered by the particles 242 is emitted from the bright display subpixel. Since the user sees the emitted light scattered by the second particle 242 in addition to the reflected light of the external light from the second particle 242, the bright display sub-pixel has a bright intrinsic color bright display. When the outside light is weak, the user causes the first subpixel 211, the second subpixel 212, and the third subpixel 213 that form the bright display pixel to emit light from the light emitting element LED to generate white light. Thus, even if the outside light is weak, it can be recognized as a bright display pixel. Eventually, the bright display pixels become brighter, and thus the contrast ratio between light and dark is large, and the electro-optical device 150 performs a clear display.

  As shown in FIG. 4D, in the dark display subpixel in the color mode, the charged first particles 241 are collected in the vicinity of the common electrode 23 in a state where the light emitting element LED is not emitting light. Since the first particles 241 are positively charged, the potential of the common electrode 23 is made lower than the potential of the pixel electrode 22 to collect the first particles 241 near the common electrode 23. As a result, the user sees the first particles 241. However, the light emitting element LED may emit light weakly depending on the use conditions. Even in this case, since the emitted light is blocked by the first particles 241 collected in the vicinity of the common electrode 23, it is not emitted from the dark display sub-pixel. In any case, since the user sees the first particle 241, the dark display sub-pixel has a very dark display. As can be seen from these explanations, the second particles 242 have higher reflectivity than the first particles 241, and the first particles 241 are charged and the second particles 242 are not charged. The emitted light can be efficiently extracted by the bright display subpixel, and the dark display subpixel can be darkly displayed. In other words, the first particles 241 are charged and absorb light, and the second particles 242 are preferably electrically positive and scatter light well.

"Potential relationship"
FIG. 5 is a diagram for explaining a bright display subpixel in the monochrome mode, where (a) is a circuit diagram and (b) is a cross-sectional view. 6A and 6B are diagrams for explaining the dark display subpixel in the monochrome mode, where FIG. 6A is a circuit diagram and FIG. 6B is a cross-sectional view. 7A and 7B are diagrams for explaining a bright display subpixel in the color mode, where FIG. 7A is a circuit diagram and FIG. 7B is a cross-sectional view. FIG. 8 is a diagram for explaining the dark display subpixel in the color mode, in which (a) is a circuit diagram and (b) is a cross-sectional view. Next, the potential relationship for realizing the above-described operation state will be described with reference to FIGS. In these figures, there is a thing in which the number is omitted like the first substrate 80, but the number is the same as that in FIG. In addition, although specific numbers are written as potentials, these numbers are a preferable example for easy understanding of the explanation. Of course, if the conditions described below are satisfied, there are potential relationships other than these specific examples. Is possible.

(1) Display conditions of electrophoretic element EPD The display conditions of the electrophoretic element EPD will be described with reference to FIGS. 5 and 6. The bright signal V _s (B) supplied to the signal line 40 to make the electrophoretic element EPD bright display is set to the second low potential L ₂ (V _s (B) = L ₂ ). Further, the dark signal V _s (D) supplied to the signal line 40 in order to make the electrophoretic element EPD dark display is set to the second high potential H ₂ (V _s (D) = H ₂ ). Further, the potential V _com supplied to the common electrode 23 is set to the third low potential L ₃ (V _com = L ₃ ). In this way, the bright display condition on the pixel electrode 22 is expressed by Equation 1.

  On the other hand, the dark display condition on the pixel electrode 22 is expressed by Equation 2.

(2) Monochromatic Mode With reference to FIGS. 5 and 6, the potential relationship in the monochrome mode will be described. When the light emitting element LED does not emit light, the potential supplied to the first power supply line 41 is V _P1 (NE), and the potential supplied to the second power supply line 31 is V _P2 (NE). If it carries out like this, the non-light-emission conditions of light emitting element LED will become Numerical formula 3.

The potential V _A of the anode electrode A is expressed by Equation 3 as Equation 4.

Next, a bright display condition on the anode electrode A in the monochrome mode will be considered with reference to FIG. If the potential V _A of the anode electrode A and the potential V _com or more common electrode 23, the first particles 241, according to Equation 1, the most potential are collected in the vicinity of the lower pixel electrode 22. On the contrary, if the potential V _A of the anode electrode A is lower than the potential V _com of the common electrode 23, the first particles 241 are collected near the pixel electrode 22 or near the anode electrode A according to this condition and Equation 1. It is done. In any case, since the first particles 241 are moved away from the common electrode 23, a bright display state is established. That is, as long as Formula 1 is satisfied, the potential V _A of the anode electrode A is not asked and the bright display condition is satisfied.

Next, a dark display condition on the anode electrode A in the monochrome mode will be considered with reference to FIG. If the potential V _A of the anode electrode A is higher than the potential V _com of the common electrode 23 (Equation 5), on the anode electrode A becomes a dark display.

  In view of Equation 4, Equation 5 is satisfied when Equation 6 holds.

  Therefore, the dark display condition on the anode electrode A in the monochrome mode is expressed by Equation 7.

  Equations (1), (2), and (7) are conditions that enable the subpixel 21 to be switched between bright display and dark display in the monochrome mode.

(3) Color Mode With reference to FIGS. 7 and 8, the potential relationship in the color mode will be described. The potential V _P1 (E) supplied to the first power supply line 41 when the light emitting element LED emits light is set to the third high potential H ₃ (V _P1 (E) = H ₃ ). Further, the potential V _P2 (E) supplied to the second power supply line 31 when the light emitting element LED emits light is set to the fourth low potential L ₄ (V _P2 (E) = L ₄ ). When the light emission threshold voltage V _thEL of the light emitting element LED is used, the light emission condition of the light emitting element LED is expressed by Equation 8 in which the light emitting element LED is expressed as a forward bias.

  On the other hand, the condition for turning on the P-type driving transistor DT is expressed by Equation 9.

Next, a bright display condition in the color mode will be considered with reference to FIG. In this case, since it is sufficient that the first particles 241 are collected in the vicinity of the pixel electrode 22, if the potential V _A of the anode electrode A is larger than the bright signal V _s (B) together with Equation 1, the anode electrode A The first particles 241 do not collect on the top, and the emitted light is scattered by the second particles 242 and emitted outside the subpixel 21.

  In consideration of Equation 8, if Equation 11 holds, Equation 10 is satisfied.

Next, dark display conditions in the color mode are considered with reference to FIG. In this case, since the first particles 241 need only be collected in the vicinity of the common electrode 23, it is sufficient that the potential V _A of the anode electrode A is higher than the potential V _com of the common electrode 23 together with Formula 2 (Formula 12).

  Considering Equation 8, if Equation 13 holds, Equation 12 is satisfied.

Since L ₂ <L _{3 according} to Equation 1, when Equation 13 is satisfied, Equation 11 is also automatically satisfied.

  On the other hand, the condition that the P-type driving transistor DT is turned off and the light-emitting element LED does not emit light is expressed by Equation 14.

Next, the condition for turning on when the N-type selection transistor ST receives the first high potential H ₁ as the selection signal V _g (S) (V _g (S) = H ₁ ) is expressed by Equation 15. is there.

On the other hand, when the N-type selection transistor ST receives the first low potential L ₁ as the non-selection signal V _g (NS) (V _g (NS) = L ₁ ), the condition for turning off is expressed by Equation 16. is there.

  Summarizing Formula 16, Formula 1, Formula 2, Formula 13, Formula 14, and Formula 15, Formula 17 is obtained.

  Expression 17 is also expressed as Expression 18.

  By satisfying Expression 17 or Expression 18 and Expression 7, it is possible to freely switch between bright display and dark display in both the monochrome mode and the color mode, and furthermore, the light emission of the bright display subpixel 21 in the color mode. The element LED can emit light, and the light emitting element LED of the dark display subpixel 21 can be made non-light emitting.

  Regarding Formula 7, it is preferable to use Formula 19 in order to suppress excessive current generation (leakage current of the light emitting element LED) and to darken the dark display subpixel 21 as much as possible.

Since it is preferable that the number of power supplies (potential types) is small, as shown in Equation 20, V _p1 (NE) and V _p2 (NE) should match V _S (D) or V _p1 (E). Is preferred.

  In this manner, the first power supply line 41 is supplied with a high potential (the third high potential during light emission, the second high potential or the third high potential during non-light emission), and the second power supply line 31 is supplied with a high potential (non-light emission). Sometimes a second high potential or a third high potential) or a low potential (fourth low potential during light emission) is supplied.

An example of the potential relationship reflecting Formula 17 (Formula 18), Formula 19 and Formula 20 is as follows, assuming V _thEL = 10V. V _g (NS) = L ₁ = 0 V, V _S (B) = L ₂ = 0 V, V _com = L ₃ = 5 V, V _P2 (E) = L ₄ = 6 V, V _P1 (E) = H ₃ = 19V, V _S (D) = H ₂ = 20V, V _g (S) = H ₁ = 25V, V _p1 (NE) = V _p2 (NE) = V _S (D) = H ₂ = 20V. These potentials are described as an example in FIGS.

As shown in FIG. 5, in order to display the sub-pixel 21 brightly in the monochrome mode, V _S (B) = L ₂ = 0 V, the potential of the pixel electrode 22 is set to the potential of the common electrode 23 or the anode electrode A. The first particles 241 may be collected in the vicinity of the pixel electrode 22 by setting the potential lower than the potential. Since V _p1 (NE) = V _p2 (NE) = V _S (D) = H ₂ = 20V, V _A = 20V.

As shown in FIG. 6, in order to darkly display the subpixel 21 in the monochrome mode, V _S (D) = H ₂ = 20 V, and the potential of the common electrode 23 is set to the potential of the pixel electrode 22 or the anode electrode A. The first particles 241 may be collected in the vicinity of the common electrode 23 with a potential lower than the potential. Since V _p1 (NE) = V _p2 (NE) = V _S (D) = H ₂ = 20V, V _A = 20V.

As shown in FIG. 7, in order to display the subpixels 21 brightly in the color mode, a low potential (fourth low potential) is supplied to the second power supply line 31 so that the light emitting element LED can emit light. Above, the potential V _px of the pixel electrode 22 is set lower than Vp1 (E), the driving transistor DT is turned on, and the light emitting element LED is caused to emit light. For this purpose, V _S (B) = L ₂ = 0V may be set. At this time, the potential V _px of the pixel electrode 22 is set lower than the potential V _com of the common electrode 23 or the potential of the anode electrode A, and the pixel electrode 22 First particles 241 are collected in the vicinity of 22. The width of the drive transistor DT is such that the on-resistance of the drive transistor DT during the linear operation is sufficiently smaller than the resistance of the light emitting element LED (that is, the drive transistor DT is in a linear state when the light emitting element LED emits light). It is preferable to take a large ratio between the length and the length. As a result, the potential drop at the driving transistor DT becomes very small. As shown in FIG. 7, for example, V _A is about 18 V, and the potential of the anode electrode A during light emission is set to a potential close to the third high potential. Can do.

As shown in FIG. 8, in order to darkly display the sub-pixel 21 in the color mode, V _S (D) = H ₂ = 20 V, and the potential of the common electrode 23 is the potential of the pixel electrode 22 or the potential of the anode electrode A. The first particles 241 may be collected near the common electrode 23. At this time, since V _P2 (E) = L ₄ = 6V, V _A > 6V, and the first particles 241 are collected in the vicinity of the common electrode 23. V _P1 (E) is larger than V _P2 (E), but since the driving transistor DT is in the OFF state, the light emitting element LED does not emit light. This is a result of V _S (D) = H ₂ > V _P1 (E) = H ₃ and the drive transistor DT being P-type. When the sub-pixel 21 is in the non-selection period, the potential V _px of the pixel electrode 22 may gradually decrease due to the leakage current of the selection transistor ST. In that case, when the threshold voltage of the driving transistor DT is V _thDT and V _px <V _P1 (E) + V _thDT , the driving transistor DT can be turned on. Then the potential V _A of the anode electrode A gradually rises, the potential V _A of the anode electrode A exceeds the light-emitting element LED of the light emission threshold _{(V P2 (E) + V} thEL), the light emitting element LED is emitting light (State shown in FIG. 4D). However, even if the light-emitting light-emitting device LED, the more potential V _A of the anode electrode A is raised, first in the vicinity of the emitted light because the first particles 241 are relegated strongly in the vicinity of the common electrode 23 common electrode 23 The particles 241 block the emission light from being emitted from the dark display subpixel 21. That is, the dark display subpixel 21 maintains the dark display as it is.

In order to achieve a clear color display with high saturation, the potentials of H ₃ , H ₂ , and H ₁ are increased while satisfying Equation 17 or Equation 18. For example, L ₁ = 0V, L ₂ = 0V, L ₃ = 5V, L ₄ = 6V, H ₃ = 24V, H ₂ = 25V, H ₁ = 30V, etc. This increases the ratio of the intensity of the emitted light to the external light, thus realizing a beautiful color display. Depending on the brightness of external light, the potentials of H ₃ , H ₂ , and H ₁ are changed as appropriate while satisfying Equation 17 or Equation 18.

"Electronics"
Next, the electronic apparatus 100 to which the above-described electro-optical device 150 is applied will be described with reference to FIGS. In the following, the case where the above-described electro-optical device 150 is applied to electronic paper and an electronic notebook is taken as an example.

  FIG. 9 is a perspective view illustrating a configuration of electronic paper. As shown in FIG. 9, the electronic paper 400 includes an electro-optical device 150 according to the present embodiment. The display area 10 is displayed with high contrast and high image retention. The electronic paper 400 has flexibility, and is composed of a rewritable sheet that exhibits the same texture and flexibility as conventional paper.

  FIG. 10 is a perspective view illustrating a configuration of an electronic notebook. As shown in FIG. 10, an electronic notebook 500 is obtained by bundling a plurality of electronic papers 400 shown in FIG. 9 and sandwiching them between covers 501. The cover 501 includes a display data input unit for inputting display data sent from an external device, for example. Thereby, according to the display data, the display content can be changed or updated while the electronic paper 400 is bundled.

  Since the electronic paper 400 and the electronic notebook 500 described above include the electro-optical device 150 according to this embodiment, high-quality image display can be performed. In addition to the above, the electro-optical device 150 according to the present embodiment can be applied to electronic devices such as a wristwatch, a mobile phone, and a portable audio device.

As described above, according to the electro-optical device 150 according to the present embodiment, the following effects can be obtained.
In a monochromematic display usage environment, display is performed by switching the display of the electrophoretic element EPD while the light emitting element LED is not emitting light. In a multicolor display or color display usage environment, light emission and non-light emission can be controlled for each subpixel 21. . Accordingly, multicolor display can be performed without using a color filter. Since each subpixel 21 is provided with a self-luminous element, high-saturation and beautiful multicolor display is possible. Thus, both monochrome display by the electrophoretic element EPD and color display by the light emitting element LED can be achieved. In a bright environment where the external light is strong, the light emitting element LED is not emitted, and display is performed by switching the display of the electrophoretic element EPD. In a dim place where the external light is weak, the light emitting element LED is emitted by the bright display subpixel of the electrophoretic element EPD. Thus, the light emitting element LED can be made to emit no light in the dark display subpixel. That is, energy consumption can be suppressed in a bright usage environment. In a dark usage environment, the light-emitting element LED can emit light in the bright display sub-pixel, and the light-emitting element LED can emit no light in the dark display sub-pixel. In other words, when the electrophoretic element EPD performs a bright display, the light emitting element LED can emit light. The bright display of the electrophoretic element EPD reflects external light, and the light emitting element LED further emits light, so that the bright display becomes extremely bright. Further, even when the outside light is weak, it is easy to distinguish between bright display and dark display, and even when the electro-optical device 150 is used in a dim place, an easy-to-view display is made. Therefore, even in a dark usage environment, the contrast ratio of light and dark is large, and the electro-optical device 150 that performs clear display can be obtained. In other words, it is possible to obtain high image quality with a multicolor electrophoretic display device, and it is possible to perform display suitable for the use environment.

(Embodiment 2)
"Form in which the first particles are negatively charged"
11A and 11B are diagrams for explaining a bright display subpixel in the monochromatic mode of the electro-optical device according to the second embodiment, where FIG. 11A is a circuit diagram and FIG. 11B is a cross-sectional view. 12A and 12B are diagrams illustrating dark display subpixels in the monochrome mode of the electro-optical device according to the second embodiment. FIG. 12A is a circuit diagram, and FIG. 12B is a cross-sectional view. 13A and 13B are diagrams illustrating a bright display subpixel in the color mode of the electro-optical device according to the second embodiment, where FIG. 13A is a circuit diagram and FIG. 13B is a cross-sectional view. 14A and 14B are diagrams illustrating dark display subpixels in the color mode of the electro-optical device according to the second embodiment, in which FIG. 14A is a circuit diagram and FIG. 14B is a cross-sectional view. The electro-optical device according to this embodiment will be described below. In addition, about the component same as Embodiment 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The electro-optical device according to the present embodiment (FIG. 11) differs from the electro-optical device according to the first embodiment (FIG. 2) in the charging polarity of the first particles 241. Other configurations are almost the same as those of the first embodiment. In the first embodiment (FIG. 2), the first particles 241 are positively charged. Along with this, the P-type drive transistor DT has been used. On the other hand, in the present embodiment (FIG. 11), the first particles 241 are negatively charged, and the driving transistor DT is an N type. Hereinafter, the configuration of the sub-pixel 21 will be described with reference to FIG.

  As shown in FIG. 11A, a first power supply line 41 and a second power supply line 31 are wired to the subpixel 21 and a common electrode 23 is provided. The subpixel 21 is formed with an electrophoretic element EPD and a light emitting element LED. The electrophoretic element EPD includes a pixel electrode 22, a common electrode 23, and an electrophoretic material 24 sandwiched between the pixel electrode 22 and the common electrode 23. On the other hand, the light emitting element LED includes an anode electrode A, a cathode electrode C, and a light emitting layer 25 (see FIG. 11B) sandwiched between the anode electrode A and the cathode electrode C. The subpixel 21 further includes a selection transistor ST, a driving transistor DT, and a capacitive element Cp. In this embodiment, both the selection transistor ST and the driving transistor DT are composed of N-type thin film transistors.

  The electrical connection relationship between the selection transistor ST and the capacitive element Cp is the same as that in the first embodiment. The anode electrode A, the cathode electrode C, and the drive transistor DT are disposed between the first power supply line 41 and the second power supply line 31. Specifically, the source of the driving transistor DT is electrically connected to the second power supply line 31, and the gate of the driving transistor DT is electrically connected to the drain of the selection transistor ST, the pixel electrode 22, and one electrode of the capacitor element Cp. The drain of the driving transistor DT is electrically connected to the cathode electrode C of the light emitting element LED. The anode electrode A of the light emitting element LED is electrically connected to the first power supply line 41. For ease of explanation, as in the first embodiment, one of the source and drain of the transistor is named a source, and the other is named a drain. In FIG. 11A to FIG. 14A, these are represented by s and d. Further, the meaning that the terminal 1 and the terminal 2 are electrically connected is the same as that of the first embodiment. For example, the cathode electrode C is electrically connected to the second power supply line 31 in FIG.

  Next, a cross-sectional structure of the electro-optical device 150 will be described with reference to FIG. The difference from the first embodiment is the charging polarity of the first particles 241 and the structure of the light emitting element LED. The light emitting element LED is formed on the first substrate 80, and the pixel electrode 22 and the light emitting surface of the light emitting element LED (the surface of the light emitting element LED located on the second substrate 90 side, in this embodiment, the cathode electrode C) are on the same layer. Is formed. The anode electrode A is formed of the same material (indium tin oxide) on the same layer (second interlayer insulating film) as the pixel electrode 22. On the other hand, the cathode electrode C is formed on the light emitting layer 25 with aluminum or magnesium. In FIG. 11B, it seems that the cathode electrode C and the pixel electrode 22 are in different layers. However, since the light emitting layer 25 is as thin as less than several hundred nm and the light emitting element LED is a thin film element, The cathode electrode C and the pixel electrode 22 are formed in the same layer (second interlayer insulating film). The other configuration is almost the same as that of the first embodiment.

  The electrophoretic material 24 includes first particles 241 and second particles 242, where the first particles 241 are charged and the second particles 242 are not charged. The first particles 241 have a color tone with low light reflectance and contribute to dark display. As an example, the first particles 241 are black, and are negatively charged in this embodiment. The second particles 242 have a color tone with high light reflectance and contribute to bright display. As an example, the second particles 242 are white, and in this embodiment, no positive charging process is performed, and the second particles 242 are electrically neutral. The electrophoretic element EPD can switch between bright display and dark display. The bright display is a display in which the user sees the color of the second particles 242, and the dark display is a display in which the user feels black. In the present embodiment, since the second particles 242 are white, the bright display is white. However, if the second particles 242 are red, the bright display is red.

  Next, the potential relationship will be described with reference to FIGS. In these figures, there is a thing in which the number is omitted like the first substrate 80, but the number is the same as that in FIG. In addition, although specific numbers are written as potentials, these numbers are preferable examples for easy understanding of the explanation, and other potential relations are possible as long as the conditions described below are satisfied. .

(1) Display conditions of electrophoretic element EPD The display conditions of the electrophoretic element EPD will be described with reference to FIGS. 11 and 12. The bright signal V _s (B) supplied to the signal line 40 to make the electrophoretic element EPD bright display is set to the first second high potential H ₁₂ (V _s (B) = H ₁₂ ). Further, the dark signal V _s (D) supplied to the signal line 40 to make the electrophoretic element EPD dark display is set to the first second low potential L ₁₂ (V _s (D) = L ₁₂ ). Further, the potential V _com supplied to the common electrode 23 is set to the first third high potential H ₁₃ (V _com = H ₁₃ ). Thus, the bright display condition on the pixel electrode 22 is expressed by Equation 21.

  On the other hand, the dark display condition on the pixel electrode 22 is expressed by Equation 22.

(2) Monochromatic Mode With reference to FIGS. 11 and 12, the potential relationship in the monochrome mode will be described. When the light emitting element LED does not emit light, the potential supplied to the first power supply line 41 is V _P1 (NE), and the potential supplied to the second power supply line 31 is V _P2 (NE). If it carries out like this, the non-light-emission conditions of light emitting element LED will become Numerical formula 23.

The potential V _C of the cathode electrode C is expressed as Expression 24 by Expression 23.

Next, a bright display condition on the cathode electrode C in the monochrome mode will be considered with reference to FIG. If the potential V _C of the cathode electrode C is less potential V _com of the common electrode 23, the first particles 241, according to Equation 21, the most potential are collected in the vicinity of the high pixel electrode 22. On the contrary, if the potential V _C of the cathode electrode C is higher than the potential V _com of the common electrode 23, the first particles 241 are collected near the pixel electrode 22 or near the cathode electrode C according to this condition and Equation 21. . In any case, since the first particles 241 are moved away from the common electrode 23, a bright display state is established. That is, as long as Formula 21 is satisfied, the potential V _C of the cathode electrode C is not asked and the bright display condition is satisfied.

Next, a dark display condition on the cathode electrode C in the monochrome mode will be considered with reference to FIG. If the potential V _C of the cathode electrode C is lower than the potential V _com of the common electrode 23 (Equation 25), on the cathode electrode C becomes a dark display.

  In view of Equation 24, Equation 25 is satisfied when Equation 26 holds.

  Therefore, the dark display condition on the cathode electrode C in the monochromatic mode is expressed by Equation 27.

  Expressions 21, 22 and 27 described above are conditions that enable the subpixel 21 to be switched between bright display and dark display in the monochrome mode.

(3) Color Mode With reference to FIGS. 13 and 14, the potential relationship in the color mode will be described. The potential V _P1 (E) supplied to the first power supply line 41 when the light emitting element LED emits light is set to the first fourth high potential H ₁₄ (V _P1 (E) = H ₁₄ ). Further, the potential V _P2 (E) supplied to the second power supply line 31 when the light emitting element LED emits light is set to the first third low potential L ₁₃ (V _P2 (E) = L ₁₃ ). When the light emission threshold voltage V _thEL of the light emitting element LED is used, the light emission condition of the light emitting element LED is expressed by Equation 28 in which the light emitting element LED is expressed as a forward bias.

  On the other hand, the condition for turning on the N-type driving transistor DT is expressed by Equation 29.

Next, a bright display condition in the color mode will be considered with reference to FIG. In this case, since it is sufficient that the first particles 241 are collected in the vicinity of the pixel electrode 22, if the potential V _C of the cathode electrode C is smaller than the bright signal V _s (B) together with Equation 21, the cathode electrode C is used. The first particles 241 do not collect on the top, and the emitted light is scattered by the second particles 242 and emitted outside the subpixel 21.

  In consideration of Equation 28, if Equation 31 holds, Equation 30 is satisfied.

Next, a dark display condition in the color mode will be considered with reference to FIG. In this case, since the first particles 241 need only be collected in the vicinity of the common electrode 23, it is sufficient that the potential V _C of the cathode electrode C together with the formula 22 is lower than the potential V _com of the common electrode 23 (formula 32).

  In consideration of Equation 28, if Equation 33 holds, Equation 32 is satisfied.

Since H ₁₂ > H _{13 according} to Expression 21, when Expression 33 is satisfied, Expression 31 is also automatically satisfied.

  On the other hand, the condition that the N-type driving transistor DT is turned off and the light emitting element LED does not emit light is expressed by Equation 34.

Next, when the N-type selection transistor ST receives the first high potential H ₁ as the selection signal V _g (S) (V _g (S) = H ₁ ), the condition for turning on is expressed by Equation 35. is there.

On the other hand, when the N-type selection transistor ST receives the first low potential L ₁ as the non-selection signal V _g (NS) (V _g (NS) = L ₁ ), the condition for turning off is expressed by Equation 36. is there.

  Summarizing Formula 36, Formula 21, Formula 22, Formula 33, Formula 34, and Formula 35 yields Formula 37.

  Expression 37 is also expressed as Expression 38.

  By satisfying Expression 37 or Expression 38 and Expression 27, it is possible to freely switch between bright display and dark display in the monochrome mode and the color mode, and further, the light emission of the bright display subpixel 21 in the color mode. The element LED can emit light, and the light emitting element LED of the dark display subpixel 21 can be made non-light emitting.

  Regarding Expression 27, it is preferable to use Expression 39 in order to suppress excessive current generation (leakage current of the light emitting element LED) and to make the dark display subpixel 21 as dark as possible at the same time.

Since it is preferable that the number of power supplies (potential types) is small, as shown in Equation 40, V _p1 (NE) and V _p2 (NE) should be matched with V _S (D) or V _p2 (E). Is preferred.

  In this way, the second power supply line 31 is supplied with a low potential (the first third low potential during light emission, the first second low potential or the first third low potential during non-light emission), and the first power supply line 41 has a low potential. (First second low potential or first third low potential during non-light emission) or high potential (first fourth high potential during light emission) is supplied.

An example of the potential relationship reflecting Formula 37 (Formula 38), Formula 39, and Formula 40 is as follows with V _thEL = 10V. V _g (NS) = L ₁ = 0V, V _S (D) = L ₁₂ = 0V, V _P2 (E) = L ₁₃ = 1V, V _P1 (E) = H ₁₄ = ₁₃ V, V _com = H ₁₃ = 16 V, V _S (B) = H ₁₂ = 20 V, V _g (S) = H ₁ = 25 V, V _p1 (NE) = V _p2 (NE) = V _S (D) = L ₁₂ = 0V. These potentials are described as an example in FIGS.

As shown in FIG. 11, in order to make the sub-pixel 21 brightly displayed in the monochrome mode, V _S (B) = H ₁₂ = 20 V, and the potential of the pixel electrode 22 is set to the potential of the common electrode 23 or the cathode electrode C. The first particles 241 may be collected in the vicinity of the pixel electrode 22 by setting the potential higher than the potential. Since V _p1 (NE) = V _p2 (NE) = V _S (D) = L ₁₂ = 0V, V _C = 0V.

As shown in FIG. 12, in order to darkly display the subpixel 21 in the monochrome mode, V _S (D) = L ₁₂ = 0V, and the potential of the common electrode 23 is set to the potential of the pixel electrode 22 or the cathode electrode C. The first particles 241 may be collected in the vicinity of the common electrode 23 by setting the potential higher than the potential. Since V _p1 (NE) = V _p2 (NE) = V _S (D) = L ₁₂ = 0V, V _C = 0V.

As shown in FIG. 13, in order to display the subpixels 21 brightly in the color mode, a high potential (first fourth high potential) is supplied to the first power supply line 41 so that the light emitting element LED can emit light. After that, the potential V _px of the pixel electrode 22 is set higher than Vp2 (E), the driving transistor DT is turned on, and the light emitting element LED is caused to emit light. For this purpose, V _S (B) = H ₁₂ = 20 V may be set. At this time, the potential V _px of the pixel electrode 22 is set higher than the potential V _com of the common electrode 23 or the potential of the cathode electrode C, and the pixel electrode 22 First particles 241 are collected in the vicinity of 22. The width of the drive transistor DT is such that the on-resistance of the drive transistor DT during the linear operation is sufficiently smaller than the resistance of the light emitting element LED (that is, the drive transistor DT is in a linear state when the light emitting element LED emits light). It is preferable to take a large ratio between the length and the length. As a result, the potential drop at the drive transistor DT becomes very small. As shown in FIG. 13, for example, V _C is about 2 V, and the potential of the cathode electrode C during light emission is set to a potential close to the first third low potential. I can do things.

As shown in FIG. 14, in order to darkly display the sub-pixel 21 in the color mode, V _S (D) = L ₁₂ = 0V, and the potential of the common electrode 23 is the potential of the pixel electrode 22 or the potential of the cathode electrode C. The first particles 241 may be collected near the common electrode 23. At this time, since V _P1 (E) = H ₁₄ = ₁₃ V, V _C < ₁₃ V, and the first particles 241 are collected in the vicinity of the common electrode 23. V _P1 (E) is larger than V _P2 (E), but since the driving transistor DT is in the OFF state, the light emitting element LED does not emit light. This is a result of V _S (D) = L ₁₂ <V _P2 (E) = L ₁₃ and the drive transistor DT being N-type. That is, the dark display subpixel 21 maintains the dark display as it is.

  As described above, according to the electro-optical device 150 according to the present embodiment, the same effects as those of the first embodiment can be obtained.

  In addition, this invention is not limited to embodiment mentioned above, A various change and improvement can be added to embodiment mentioned above. A modification is described below.

(Modification 1)
"Forms with different pixel shapes"
In the first embodiment (FIG. 2), one pixel 20 is, for example, a square and is composed of three rectangular sub-pixels 21. However, the shape of the pixel 20 is not limited to this, and various forms are possible. It is. FIG. 15 is a plan view for explaining a part of the display area of the electro-optical device. FIG. 16 is a plan view for explaining one pixel of the electro-optical device. Next, the planar shape of the pixel 20 and the sub-pixel 21 will be described with reference to FIGS. 15 and 16.

  The planar shape of the sub-pixel 21 may be any as long as the display region 10 can be planarly filled (if it can be covered with a flat surface without any gap). That is, the subpixel 21 may be a triangle, a rectangle, or a hexagon. For example, as shown in FIG. 15, the sub-pixel 21 can be a regular hexagon. A plurality of these sub-pixels 21 are collected to constitute one pixel 20. In FIG. 15, three subpixels 21 (211, 212, and 213) are collected so as to be in contact with each other to form one pixel 20. In this way, full color display is realized. A light emitting element LED is arranged at the center of each subpixel. As described in detail in the first embodiment, the planar shape of the light emitting element LED is also arbitrary. What is important is that the light emitting element LED and the pixel electrode 22 do not overlap in plan view. If the light emitting element LED and the pixel electrode 22 are separated from each other in plan view, the shape of the pixel 20 and the subpixel 21 can be arbitrarily set.

  In FIG. 15, one pixel 20 is constituted by three subpixels 21, but the number of subpixels 21 constituting the pixel 20 is not limited to this. For example, one pixel 20 may be composed of two subpixels 21 including a first subpixel 211 that displays red and a second subpixel 212 that displays green. In this case, although full-color display is not realized, a large number of colors mixed by red and green can be displayed, and multi-color display is realized. Further, for example, as shown in FIG. 16A, the first subpixel 211 for displaying one pixel 20 in red, the second subpixel 212 for displaying green, the third subpixel 213 for displaying blue, and the first subpixel 213 for displaying yellow. You may comprise by the four subpixels 21 with the four subpixels 214. FIG. In this case, a beautiful full-color display that enables rich color expression is realized. Further, for example, four subpixels of a first subpixel 211 that displays one pixel 20 in red, a second subpixel 212 that displays green, a third subpixel 213 that displays blue, and a fourth subpixel 214 that displays white 21 may be used. In this case, white display in full color display can be brightened. Also, for example, as shown in FIG. 16B, the first subpixel 211 that displays one pixel 20 in red, the second subpixel 212 that displays green, the third subpixel 213 that displays blue, and the first subpixel 213 that displays yellow. You may comprise by the five subpixels 21 of the 4th subpixel 214 and the 5th subpixel 215 which displays white. In this case, it is possible to achieve beautiful full-color display and bright white display that enable rich color expression. Further, for example, as shown in FIG. 16C, the first subpixel 211 that displays one pixel 20 in red, the second subpixel 212 that displays green, the third subpixel 213 that displays blue, and the first subpixel 213 that displays blue. You may comprise the 6 subpixel 21 of the 4th subpixel 214, the 5th subpixel 215 which displays magenta, and the 6th subpixel 216 which displays yellow. In this case, a beautiful full-color display that enables extremely rich color expression is realized. Further, for example, as shown in FIG. 16D, the first sub-pixel 211 for displaying one pixel 20 in red, the second sub-pixel 212 for displaying green, the third sub-pixel 213 for displaying blue, and the first sub-pixel 213 for displaying blue. The four sub-pixels 214, the fifth sub-pixel 215 for magenta display, the sixth sub-pixel 216 for yellow display, and the seventh sub-pixel 217 for white display may be used. In this case, it is possible to achieve a beautiful full color display and a bright white display that enable an extremely rich color expression. As described above, the number of sub-pixels 21 constituting one pixel 20 is not limited to three, and may be two or more than four.

  DESCRIPTION OF SYMBOLS 10 ... Display area, 20 ... Pixel, 21 ... Sub pixel, 22 ... Pixel electrode, 23 ... Common electrode, 24 ... Electrophoretic material, 25 ... Light emitting layer, 30 ... Scan line, 31 ... Second power supply line, 40 ... Signal Line 41, first power line 80, first substrate 90, second substrate 100, electronic device 150, electro-optical device 211, first subpixel 212, second subpixel 213, third Subpixel, 214 ... fourth subpixel, 215 ... fifth subpixel, 216 ... sixth subpixel, 217 ... seventh subpixel, 241 ... first particle, 242 ... second particle, DT ... drive transistor, EPD ... Electrophoresis element, LED1 ... first light emitting element, LED2 ... second light emitting element, LED3 ... third light emitting element, ST ... selection transistor.

Claims (9)

Have pixels,
The pixel includes a first subpixel and a second subpixel,
The first subpixel is provided with a first light emitting element that mainly emits light of a first color, and an electrophoretic element,
The second subpixel is provided with a second light emitting element that mainly emits a second color different from the first color, and the electrophoretic element,
A first substrate and a second substrate;
The electrophoretic element includes a pixel electrode formed on the first substrate, a common electrode formed on the second substrate, and an electrophoretic material disposed between the pixel electrode and the common electrode. Including
The first light emitting element and the second light emitting element are formed on the first substrate,
The pixel electrode in the first subpixel does not overlap the first light emitting element in plan view,
The electro-optical device, wherein the pixel electrode in the second subpixel does not overlap the second light emitting element in a plan view. The pixel further includes a third sub-pixel;
The third sub-pixel is provided with a third light-emitting element that mainly emits a third color different from the first color and the second color, and the electrophoretic element,
The third light emitting element is formed on the first substrate;
2. The electro-optical device according to claim 1, wherein the pixel electrode in the third sub-pixel does not overlap the third light-emitting element in a plan view. The electrophoretic material includes first particles and second particles,
The electro-optical device according to claim 1, wherein the first particles are charged and the second particles are not charged. The first light emitting element is a light emitting diode having a first light emitting layer,
The second light emitting element is a light emitting diode having a second light emitting layer,
The electro-optical device according to claim 2, wherein the third light emitting element is a light emitting diode having a third light emitting layer. An electro-optical device in which an electrophoretic element and a light emitting element are provided in a subpixel,
The electrophoretic element can switch between bright display and dark display when the light emitting element is not emitting light,
The electro-optical device, wherein the light-emitting element is capable of switching between light emission and non-light emission when the electrophoretic element performs the bright display.   6. The electro-optical device according to claim 5, wherein when the electrophoretic element emits light during the bright display, a part of the emitted light is emitted from the subpixel.   When the first light emitting element emits light when the first particles are collected in the vicinity of the pixel electrode, the emitted light is scattered by the second particles, and a part of the emitted light is the first sub-light. The electro-optical device according to claim 3, wherein the electro-optical device is emitted from a pixel. With sub-pixels,
A first power line and a second power line are wired to the subpixel,
The sub-pixel includes a selection transistor, a driving transistor, a pixel electrode, an anode electrode, a cathode electrode, a light emitting layer provided between the anode electrode and the cathode electrode,
The pixel electrode, the drain of the selection transistor, and the gate of the driving transistor are electrically connected, and the driving transistor, the anode electrode, and the cathode electrode are interposed between the first power supply line and the second power supply line. Is placed,
A potential capable of setting a potential difference between the first power supply line and the second power supply line to a potential difference that the light emitting layer emits light and a potential difference that does not emit light can be supplied to the first power supply line and the second power supply line, respectively. Electro-optical device characterized. A signal line and a scanning line;
The sub-pixel is disposed corresponding to an intersection of the signal line and the scanning line,
A source of the selection transistor and the signal line are electrically connected;
9. The electro-optical device according to claim 8, wherein a gate of the selection transistor and the scanning line are electrically connected.

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