JP2011237581A - Electrophoresis display device and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophoresis display device capable of controlling three color attributes of brightness, chroma saturation and hue or at least one thereof by controlling movement of particles while providing a satisfactory and stable color display without causing an operational failure, and further to provide an electronic device.SOLUTION: An electrophoresis display device according to the present invention includes: a first substrate; a second substrate; an electrophoresis layer 32; first pixel electrodes and second pixel electrodes, both of which are driven independently of one another; a common electrode 37; first data lines 68A and second data lines 68B; and a scanning line 66 extending in a direction crossing the first data lines 68A and the second data lines 68B. Spaces between the first data lines 68A and the second data lines 68B, both of which are alternately arranged in one direction, are wider than spaces between the adjacent first pixel electrodes, spaces between the adjacent second pixel electrodes or spaces between the adjacent first pixel electrodes and the adjacent second pixel electrodes, in the direction in which the first data lines 68A and the second data lines 68B are arranged.

Description

  The present invention relates to an electrophoretic display device and an electronic apparatus.

  In recent years, an electrophoretic display device has been used as a display unit such as electronic paper. The electrophoretic display device has an electrophoretic dispersion liquid in which a plurality of electrophoretic particles are dispersed in a liquid phase dispersion medium (dispersion medium). An electrophoretic display device is a device that uses for display that the distribution state of electrophoretic particles changes by applying an electric field and the optical characteristics of an electrophoretic dispersion change.

  In such an electrophoretic display device, a concept of a color electrophoretic display device using three particles as described in Patent Documents 1 and 2 below has been proposed. It describes that three particles of positively charged particles, negatively charged particles, and uncharged particles are driven using three electrodes.

JP 2009-9092 A JP 2007-98382 A

  However, in the above-mentioned patent document, there is a problem in controllability of brightness and saturation with one subpixel in order to realize a color electrophoretic display device, and it is difficult to perform full color display. In a color electrophoretic display device, a method of controlling three or at least one of brightness, saturation, and hue in an analog manner has not been proposed.

  The present invention has been made in view of the above-described problems of the prior art, and can control three or at least one of lightness, saturation, and hue by controlling the movement of particles and malfunction. An object of the present invention is to provide an electrophoretic display device and an electronic apparatus that can stably perform good color display without causing occurrence of color defects.

As shown in FIG. 19, the inventor has devised a layout including two pixel electrodes 135A and 135B corresponding to positively charged particles and negatively charged particles in one pixel. In this case, two transistors are provided in one pixel. TR1 and TR2 are necessary, and the number of data lines 68 inevitably increases twice. For this reason, the distance between the data lines 68 is narrowed, and a short circuit failure due to foreign matter or the like is likely to occur. As a result, there has been a problem that the yield decreases. Further, since the shield electrode is not formed on the data line 68, the voltage of the data line 68 is directly applied to the electrophoretic material of the pixel, which causes a problem that the display affects the display.
The present invention also aims to solve such problems.

  In order to solve the above problems, an electrophoretic display device of the present invention is disposed between a first substrate and a second substrate, and between the first substrate and the second substrate, and at least a dispersion medium and the dispersion medium. An electrophoretic layer having a plurality of particles mixed therein, a first electrode and a second electrode which are formed for each pixel on the electrophoretic layer side of the first substrate and are driven independently from each other, and the second electrode A third electrode having a larger area than the total area of the first electrode and the second electrode formed on the electrophoretic layer side of the substrate, and first data connected to the first electrode via a first transistor A second data line connected to the second electrode via a second transistor, and a plurality of scan lines extending in a direction intersecting the first data line and the second data line, A first data line and a second data line; The first data lines and the second data lines are alternately arranged in one direction, and an interval between the adjacent first data lines and the second data lines is determined by the first data lines. In addition, the first electrodes adjacent to each other in the arrangement direction of the second data lines, the second electrodes, or the interval between the first electrodes and the second electrodes is wider.

  According to the present invention, by applying a predetermined voltage to the first electrode, the second electrode, and the third electrode, according to the voltage difference generated between each first electrode and the second electrode and the third electrode, The movement and distribution range of charged particles can be controlled. Accordingly, it is possible to provide an electrophoretic display device that can control three or at least one of brightness, saturation, and hue, and can perform good color display. In the present invention, the first electrode and the second data line arranged alternately in one direction are spaced apart from each other between the first electrodes adjacent to each other in the arrangement direction of the first data line and the second data line. Even if two electrodes (first electrode and second electrode) are provided in one pixel, the first data line and the second electrode are larger than each other or the interval between the first electrode and the second electrode. A short circuit with the data line can be prevented. As a result, full color display can be performed without causing operation failure.

  The first data line and the second data line are preferably arranged at equal intervals.

  According to the present invention, the distance between the first data line and the second data line is widened, and a short circuit failure between the data lines due to a foreign substance or the like is prevented, thereby enabling more stable driving.

  In addition, it is preferable that the first data line or the second data line overlaps at least one of the first electrode and the second electrode in plan view.

  According to the present invention, the first data line or the second data line is shielded, and the voltages of the first and second data lines are directly applied to the electrophoretic layer, and the display is prevented from being affected by the voltage. The

  The plurality of first electrodes included in one pixel are connected to each other by a first connection electrode closer to the first substrate than the first electrode, and the plurality of first electrodes included in one pixel are included. The two electrodes are preferably connected to each other by a second connection electrode formed closer to the first substrate than the second electrode.

  According to the present invention, the same voltage can be simultaneously applied to the first electrodes or the second electrodes.

  The first connection electrode may be formed on the first data line, and the second connection electrode may be formed on the second data line.

  According to the present invention, the first connection electrode and the second connection electrode function as a shield electrode for each data line.

  Moreover, it is preferable that the first electrode and the second electrode are formed in a comb shape or an island shape.

  According to the present invention, since the first and second electrodes are formed in a comb-teeth shape or an island shape, particles can be distributed in a linear or small dot region on the third electrode side. Thereby, gradation control can be performed.

  In addition, it is preferable that the first electrode or the second electrode functions as a partition that partitions the pixel.

  According to the present invention, the first electrode or the second electrode functions as a partition partitioning a pixel, so that particles can be moved to the partition side. As a result, it is possible to display intermediate gradations.

  Further, it is preferable that the partition wall is formed on the first data line or the second data line.

  According to the present invention, the partition wall can function as a shield electrode on the first and second data lines, and it is possible to prevent malfunction caused by the voltage of each data line being directly applied to the electrophoretic layer. it can.

  In addition, the partition that holds the distance between the first substrate and the second substrate is configured by a conductive portion connected to the first transistor or the second transistor and an insulating film that covers a surface of the conductive portion. Preferably it is.

  According to the present invention, it is possible to prevent a short circuit between the third electrode formed on the second substrate side and the partition wall.

  In addition, a scanning line extending in a direction intersecting the first data line and the second data line is branched into two in the display region, and one of the branch portions is connected to the first transistor, and the other is connected to the first transistor. It is preferable to be connected to the second transistor.

  According to the present invention, the first and second transistors in a pixel can be turned on simultaneously.

  A scanning line extending in a direction intersecting with the first data line and the second data line is disposed so as to pass through a center of the pixel, and the first transistor and the second transistor are connected to the scanning line. Preferably it is.

  According to the present invention, the first and second transistors in the pixel can be turned on simultaneously, and the scanning lines on the first substrate can be easily routed.

  Further, it is preferable that the dispersion medium contains the positively charged particles of the first color and the negatively charged particles of the second color.

  According to the present invention, an arbitrary color can be displayed by controlling the movement and distribution state of each positively and negatively charged particle. That is, the movement of the charged particles toward the third electrode can be controlled by the polarity of the voltage applied to the first electrode and the second electrode. Thereby, particles of any color can be distributed on the third electrode. Full color display can be performed by mixing the colors of the particles visually recognized when viewed from the third electrode side.

Moreover, it is preferable that the dispersion medium further includes the non-charged third color particles.
According to the present invention, since the dispersion medium further includes non-charged third color particles, a plurality of colors can be displayed by combining the first color particles and the second color particles. Therefore, an electrophoretic display device capable of performing good color display can be provided.

An electronic apparatus of the present invention includes the electrophoretic display device of the present invention.
According to the present invention, it is possible to appropriately control at least one of brightness, saturation, and hue of a display image (display color) and to prevent a short circuit between data lines and perform stable color display. Therefore, a high-quality electronic device with excellent reliability can be obtained.

It is a figure which shows the whole structure of the electrophoretic display device which concerns on 1st Embodiment, Comprising: (a) Plan view, (b) Equivalent circuit diagram. FIG. 3 is a diagram illustrating a configuration of one pixel of an electrophoretic display device. FIG. 6 is a partial cross-sectional view illustrating a configuration of a sub pixel of an electrophoretic display device. The operation principle diagram of the electrophoretic display device using three particles. Equivalent circuit diagram for electrophoretic display device FIG. 3 is a plan view illustrating a pixel configuration in an electrophoretic display device. FIG. 3 is a plan view illustrating a pixel configuration in an electrophoretic display device. Sectional drawing which follows the AA line of FIG. The top view which shows the structure on the element substrate of the electrophoretic display device of 2nd Embodiment. Sectional drawing which follows the BB line of FIG. The equivalent circuit diagram which shows the structure of the electrophoretic display device of 3rd Embodiment. The top view which shows a pixel structure. The top view which shows the pixel structure of the electrophoretic display device of 4th Embodiment. FIG. 10 is a plan view illustrating a pixel configuration of an electrophoretic display device according to a fifth embodiment. Sectional drawing which follows the CC line | wire of FIG. FIG. 10 is a plan view illustrating a pixel configuration of an electrophoretic display device according to a sixth embodiment. The top view which shows the structure on the element substrate of the electrophoretic display device of other embodiment. FIG. 14 illustrates an example of an electronic device. The top view which shows a structure on the element substrate of the conventional electrophoretic display apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

[First Embodiment]
FIG. 1A is a plan view showing the overall configuration of the electrophoretic display device 100.
As shown in FIG. 1A, in the electrophoretic display device 100 according to the present embodiment, the element substrate 300 has a larger planar dimension than the counter substrate 310, and the element substrate projects outward from the counter substrate 310. COF (Chip On Film) mounting (or TAB (Tape Automated Bonding) mounting on flexible substrates 201 and 202 on which two scanning line driving circuits 61 and two data line driving circuits 62 are connected to an external device. ) Then, the flexible substrate 201 on which the scanning line driving circuit 61 is mounted is formed on the terminal formation region formed on the edge portion along one short side of the element substrate 300 with ACP (anisotropic conductive paste) or ACF (differently conductive paste). (Isotropic conductive film) or the like. Here, the element substrate 300 is configured with a first substrate 30 described later as a base, and the counter substrate 310 is configured with a second substrate 31 described later as a base.

  In addition, the flexible substrate 202 on which the data line driving circuit 62 is mounted is mounted on a terminal formation region formed on the edge portion along one long side of the element substrate 300 via ACP, ACF, or the like. A plurality of connection terminals are formed in each terminal formation region, and later-described scanning lines and data lines extending from the display unit 5 are connected to the connection terminals.

  In addition, the display unit 5 is formed in a region where the element substrate 300 and the counter substrate 310 overlap, and wirings (scanning lines 66 and data lines 68) extending from the display unit 5 include the scanning line driving circuit 61 and the data line driving circuit. 62 is extended to the area where it is mounted, and is connected to a connection terminal formed in the mounting area. Then, flexible substrates 201 and 202 are mounted on the connection terminals via ACP or ACF.

FIG. 1B is an equivalent circuit diagram showing the overall configuration of the electrophoretic display device.
As shown in FIG. 1B, the display unit 5 of the electrophoretic display device 100 has a plurality of pixels 40 arranged in a matrix. Around the display unit 5, a scanning line driving circuit 61 and a data line driving circuit 62 are arranged. The scanning line driving circuit 61 and the data line driving circuit 62 are each connected to a controller (not shown). The controller comprehensively controls the scanning line driving circuit 61 and the data line driving circuit 62 based on the image data and the synchronization signal supplied from the host device.

  A plurality of scanning lines 66 extending from the scanning line driving circuit 61 and a plurality of data lines 68 extending from the data line driving circuit 62 are formed in the display unit 5, and the pixels 40 are provided corresponding to the intersection positions thereof. It has been. Two different data lines 68A (first data lines) and data lines 68B (second data lines) are connected to the pixel 40.

  The scanning line driving circuit 61 is connected to each pixel 40 via a plurality of scanning lines 66, and sequentially selects each scanning line 66 under the control of a controller, and a selection transistor TR1 provided in the pixel 40. , TR2 (refer to FIG. 5) is supplied via the selected scanning line 66 to define the ON timing. The data line driving circuit 62 is connected to each pixel 40 via a plurality of data lines 68, and an image signal defining pixel data corresponding to each pixel 40 is supplied to the pixel 40 under the control of the controller. Supply.

FIG. 2 is a diagram illustrating a configuration of one pixel of the electrophoretic display device.
As shown in FIG. 2, when realizing color display, one pixel has three sub-pixels 40r (S), 40g (S), 40b (S) of R (red), G (green), and B (blue). The full color display is performed by controlling the light intensity of each color.
Note that the position of the sub-pixel is not limited to that illustrated.

FIG. 3 is a partial cross-sectional view illustrating a configuration of a sub-pixel of the electrophoretic display device.
The electrophoretic display device 100 has a configuration in which a three-particle electrophoretic layer 32 is provided between an element substrate 300 (first substrate) and a counter substrate 310 (second substrate). The electrophoretic layer 32 includes negatively charged black negatively charged particles 26 (Bk), positively charged white positively charged particles 27 (W) in a transparent dispersion medium 21 (T), and a non-charged magenta color. Particles 28 (M) are held. A common electrode 37 (third electrode) is formed on almost the entire display area on the electrophoretic layer 32 side of the counter substrate 310. The element substrate 300 has a circuit element layer 38 on the surface on the electrophoretic layer 32 side. A plurality of first pixel electrodes 35A (first electrodes) and a plurality of second pixel electrodes 35B (second electrodes) are formed for each subpixel S on the electrophoretic layer 32 side of the element substrate 300, that is, on the circuit element layer 38. (In FIG. 3, each pixel electrode 35A, 35B is shown one by one). Although the first pixel electrode 35A and the second pixel electrode 35B have a circular shape in plan view formed with a predetermined diameter, they may all have a uniform diameter or may be formed with different diameters depending on the product specifications. May be. Further, the planar view shape of the pixel electrodes 35A and 35B is not limited to a circular shape, but may be other shapes (for example, a polygonal shape or an elliptical shape).
The common electrode 37 has an area larger than the total area of the pixel electrodes 35A and 35B.
Further, the pixel electrode 35A and the pixel electrode 35B in the present embodiment can be driven independently of each other.

  The element substrate 300 includes a first substrate 30 made of glass, plastic, or the like, and a circuit element layer 38 formed on the first substrate 30, and is transparent because it is disposed on the side opposite to the image display surface. It may not be something. The pixel electrodes 35A and 35B are electrodes in which nickel plating and gold plating are laminated in this order on a Cu foil, or electrodes formed of Al, ITO (indium tin oxide), or the like. Although not shown, the circuit element layer 38 is formed with the scanning line 66, the data line 68, the selection transistors TR1 and TR2, and the like shown in FIGS.

On the other hand, the counter substrate 310 includes a second substrate 31 made of glass, plastic, or the like. Since the second substrate 31 is disposed on the image display side, it is a transparent substrate. A planar common electrode 37 facing the plurality of pixel electrodes 35 </ b> A and 35 </ b> B is formed on the electrophoretic layer 32 side of the second substrate 31, and the electrophoretic layer 32 is provided on the common electrode 37. The common electrode 37 is a transparent electrode formed of MgAg, ITO, IZO (indium / zinc oxide), or the like.
Such a counter substrate 310 is disposed opposite to the element substrate 300 with the partition wall 13 interposed therebetween.

  A three-particle electrophoretic layer 32 is held between the element substrate 300 and the counter substrate 310. The electrophoretic layer 32 includes black negatively charged particles 26 (Bk) (first color particles) that are negatively charged in a transparent dispersion medium 21 (T), white positively charged particles that are positively charged, red Uncharged particles 28 (R) are dispersed. The charged particles (negatively charged particles 26 (Bk), positively charged particles 27 (W)) behave as electrophoretic particles in the electrophoretic layer 32. It is assumed that the observer observes the display from the second substrate 31 side.

FIG. 4 shows the principle of operation of an electrophoretic display device using three particles.
Further, a voltage having a maximum absolute value among positive voltages applied to the pixel electrodes 35A and 35B is a voltage VH (hereinafter also referred to as a positive maximum value), and a voltage having a maximum absolute value among negative voltages. Is a voltage VL (hereinafter also referred to as a negative maximum value).
Note that “applying a voltage to an electrode” is synonymous with “supplying an electrode with a potential that generates the voltage with respect to a ground potential”.

FIG. 4A shows the distribution state of particles when red is displayed.
Here, a positive voltage VH is applied to the first pixel electrode 35A, and a negative voltage VL is applied to the second pixel electrode 35B. Then, negatively charged negatively charged particles 26 (C) are adsorbed on the first pixel electrode 35A, and positively charged positively charged particles 27 (Y) are adsorbed on the second pixel electrode 35B. Light incident from the outside is scattered by the red non-charged particles 28 (R) floating in the dispersion medium 21, becomes red, and exits from the common electrode 37 side.

FIG. 4B shows a particle distribution state when displaying black.
When switching from red display to black display, a negative voltage VL is applied to each of the first pixel electrode 35A and the second pixel electrode 35B. Then, all negatively charged negatively charged particles 26 (Bk) move to the common electrode 37 side. The positively charged positively charged particles 27 (W) are attracted onto the second pixel electrode 35B. Light incident from the outside is scattered by the negatively charged particles 26 (Bk) distributed on the common electrode 37, becomes black, and exits from the common electrode 37 side.

FIG. 4C shows a particle distribution state in white display.
Here, a voltage is first applied from the state shown in FIG. Then, a positive voltage VH is applied to the first pixel electrode 35A and the second pixel electrode 35B. Then, all the positively charged particles 27 (W) on the second pixel electrode 35B move to the common electrode 37 side. The negatively charged particles 26 (Bk) are gathered on the first pixel electrode 35A. Light incident from the outside is scattered by the positively charged particles 27 (W) distributed on the common electrode 37, becomes white, and exits from the common electrode 37 side.

FIG. 4D shows a particle distribution state when the display is dark red.
Here, a voltage is first applied from the state shown in FIG. Then, a negative voltage VL is applied to the second pixel electrode 35B to collect all the positively charged particles 27 (W) on the second pixel electrode 35B. A negative voltage Vl (Vl <VL) smaller than the negative voltage VL is applied to the first pixel electrode 35A, and a part of the negatively charged particles 26 (Bk) on the first pixel electrode 35A moves toward the common electrode 37 side. Move. As a result, a plurality of small black dots are formed on the common electrode 37, and the non-charged particles 28 (R) are distributed among these black dots. Here, the black display by the negatively charged particles 26 (B) occupies approximately 1/3 of the entire pixel area, and the red display by the uncharged particles 28 (R) occupies approximately 2/3 of the entire pixel area. ing. Dark red can be expressed by such a black display (black particle) distribution.

  Note that the amount of movement and the distribution range of the charged particles 26 (Bk) and 27 (W) toward the common electrode 37 are controlled by design factors such as the distance between the pixel electrodes 35A and 35A and the size of the pixel electrodes 35A and 35A. Or by applying voltage. In the above description, the moving amount and distribution range of the charged particles 26 (Bk) and 27 (W) are controlled by the magnitude of the voltage applied to the pixel electrodes 35A and 35B. Is possible.

The brightness is controlled by the area of the particles visually recognized when the electrophoretic layer 32 is viewed from the outside of the common electrode 37.
Here, white display by the particles 27 (W) requires incident light to be scattered a plurality of times by the particles, and therefore requires a three-dimensional depth distribution in the electrophoretic layer 32. The above-mentioned visible area refers to an effective area that is actually visually recognized including a two-dimensional and three-dimensional distribution of particles.
As described above, the brightness of each pixel can be controlled by controlling the movement amount and distribution range of the charged particles 26 and 27.

The configuration of the electrophoretic display device of this embodiment will be described in detail below.
FIG. 5 is an equivalent circuit diagram of the electrophoretic display device.
As shown in FIG. 5, in the electrophoretic display device of this embodiment, two selection transistors TR1 and TR2 and two pixel electrodes 35A and 35B are provided in one subpixel S. The pixel circuit in each sub-pixel S includes an electrophoretic layer 32 as an electro-optical material, selection transistors TR1 and TR2 that perform a switching operation for supplying a voltage to the electrophoretic layer 32, and the selection transistors TR1 and TR2. The pixel electrodes 35 </ b> A and 35 </ b> B and the common electrode 37 are connected to each other. By independently controlling the voltage applied to the pixel electrodes 35A and 35B by the two selection transistors TR1 and TR2, an image display without crosstalk can be performed.

  Specifically, the scanning lines 66 are connected to the gates of the selection transistors TR1 and TR2, the data lines 68A and 68B are connected to the sources, and the electrophoretic layer 32 is connected to the drains. Specifically, of the subpixels S (A) and S (B) adjacent in the extending column direction of the data lines 68A and 68B, in the subpixel S (A), the gates of the selection transistors TR1 and TR2 are connected. m rows of scanning lines 66 are connected. The scanning lines 66 are branched into two scanning lines 66A and 66B in the sub-pixel S, but are combined into one outside the display area, and the same voltage is applied.

  Then, the data line 68A of N (A) rows is connected to the source of the selection transistor TR1, and the pixel electrode 35A (electrophoretic layer 32) is connected to the drain via the connection electrode 44A (first connection electrode). On the other hand, the source of the selection transistor TR2 is connected to the data line 68B of the N (B) row, and the pixel electrode 35B (electrophoretic layer 32) is connected to the drain via the connection electrode 44B (second connection electrode).

6 and 7 are plan views showing pixel configurations in the electrophoretic display device.
As shown in FIG. 6, the connection electrodes 44 </ b> A and 44 </ b> B include a trunk portion 441 extending along the scanning line 66 and a plurality of branch portions 442 connected by the trunk portion 441 (two in this embodiment: 442 a and 442 b). It has. Each of the connection electrodes 44A and 44B has a comb-like shape, and is arranged in the sub-pixel S (40r, 40g, 40b) so as to engage with each other. That is, the branch portions 442b and 442b of the second connection electrode 44B exist on both sides of the branch portion 442a of the first connection electrode 44A. By making the shape of the connection electrodes 44A and 44B into a comb-teeth shape, the particles can easily move between the pixel electrodes 35A and 35B.

As shown in FIG. 6, the branch portion 442 of the first connection electrode 44A corresponds to the first pixel electrode 35A, and the branch portion 442 of the second connection electrode 44B corresponds to the second pixel electrode 35B.
A partition wall 13 is arranged so as to partition one pixel, and has a frame shape so as to surround the first pixel electrode 35A and the second pixel electrode 35B. The partition wall 13 is made of the same material as that of the liquid crystal device, and here, a photosensitive acrylic material is used. Alternatively, an inorganic material or an organic material may be used, and a thermosetting epoxy resin may be used.

  The plurality of data lines 68A and 68B are arranged at substantially equal intervals. Specifically, the interval between the adjacent data lines 68A and 68B is wider than the arrangement interval between the pixel electrodes 35A and 35B closest to the adjacent subpixel S. As a result, a sufficient distance can be secured between the data lines 68A and 68B, and defects due to a short circuit can be effectively prevented. In the case of the conventional configuration shown in FIG. 18, the occurrence rate of short-circuit defects due to foreign matters etc. was 30% in the 13.3 inch panel, but in the case of the configuration of this embodiment, it was reduced to 0.5%. It can be said that this is also effective.

Note that the interval between the adjacent data lines 68A and 68B is not necessarily an exact equal interval, and the same effect can be obtained by setting the interval so as not to cause a short circuit due to a foreign substance or the like. As is generally known, the establishment of a short between two wires decreases exponentially as the distance between the wires increases. Therefore, there is no problem if a certain distance is maintained between the wirings.
Compared with the conventional configuration (FIG. 18), if a part of the pixel electrode 35 overlaps the data lines 68A and 68B in a plan view, the distance between the data lines 68A and 68B is maintained at a certain level or more. Yield is stable.
Furthermore, since it is not necessary to provide the data lines 68A and 68B under the partition wall 13, the width of the partition wall 13 can be reduced and the aperture ratio can be improved.

  The extending directions of the data lines 68A and 68B and the branch portions 442a and 442b of the connection electrodes 44A and 44B coincide with each other, and each of the data lines 68A and 68B is in plan view with both the connection electrode 44A and the connection electrode 44B. It is formed to overlap.

  Specifically, the data line 68A overlaps a part of each trunk portion 441 of the connection electrodes 44A and 44B and the branch portion 442a of the connection electrode 44A, and the data line 68B includes the trunk portions of the connection electrodes 44A and 44B. It overlaps with a part of 441 and the branch part 442b of the connection electrode 44B. As shown in the drawing, the widths of the branch portions 442a and 442b of the connection electrodes 44A and 44B are formed to be wider than the widths of the data lines 68A and 68B.

  In the present embodiment, the first pixel electrode 35A and the second pixel electrode 35B are formed in a circular shape in plan view, but this diameter is smaller than the cell gap and is ½ of the cell gap. The following is more preferable. As a result, the size of the display dots (charged particle distribution range) on the common electrode 37 can be reduced, and a light color display becomes possible. As a result, the color range that can be expressed is expanded. A plurality of first pixel electrodes 35A and second pixel electrodes 35B formed in an island shape are provided for each pixel. For example, the total area of one pixel is 1/4 or less.

Further, the pixel electrodes 35A and 35B are arranged at a predetermined distance from each other so as not to overlap in the same pixel area.
The planar shape of the pixel electrodes 35A and 35B is not limited to a circle but may be a polygon.

8 is a cross-sectional view taken along line AA in FIG.
As shown in FIG. 8, the element substrate 300 includes a first substrate 30 made of a glass substrate having a thickness of 0.5 mm. On the surface of the first substrate 30, a gate electrode 41e (scanning line 66) made of aluminum (Al) with a thickness of 300 nm is formed. Then, a gate insulating film 41b made of a silicon oxide film having a thickness of 400 nm is formed on the entire surface of the first substrate 30 so as to cover the gate electrode 41e, and an a-IGZO (with a thickness of 50 nm is formed immediately above the gate electrode 41e. A semiconductor layer 41a made of an oxide of In, Ga, and Zn is formed.

  On the gate insulating film 41b, a source electrode 41c (data line 68) and a drain electrode 41d made of Al having a thickness of 300 nm are provided so as to partially overlap the gate electrode 41e and the semiconductor layer 41a, respectively. The source electrode 41c and the drain electrode 41d are formed so as to partially run over the semiconductor layer 41a. A first interlayer insulating film 42A made of a silicon nitride film having a thickness of 200 nm is formed thereon. In addition, a connection electrode 44A (44B) made of aluminum (Al) having a thickness of 300 nm is formed on the first interlayer insulating film 42A, and is connected to the drain electrode 41d through the contact hole H3. The connection electrode 44A (44B) is formed so as to cover the selection transistor TR1 (TR2) and the data line 68A (68B). Therefore, the pixel electrodes 35A and 35B can be formed on the selection transistor TR1 and the data line 68A (68B), and the aperture ratio can be improved.

  By providing the connection electrodes 44A and 44B covering these between the adjacent data lines 68A and 68B, the shielding effect between the adjacent data lines 68A and 68B and the reduction of the influence due to the voltage change of each data line 68A and 68B can be reduced. I can plan.

  Here, as the selection transistors TR1 and TR2, general a-Si TFTs, poly-Si TFTs, organic TFTs, oxide TFTs, and the like can be used. Both the top gate and bottom gate structures are possible.

  A second interlayer insulating film 42B made of a silicon oxide film having a thickness of 300 nm and a third interlayer made of photosensitive acrylic having a thickness of 1 μm are formed on the selection transistors TR1 and TR2 and the connection electrodes 44A and 44B so as to cover them. An insulating film 43 is formed. The third interlayer insulating film 43 functions as a planarizing film. Note that the third interlayer insulating film 43 is not necessarily required and can be omitted if the function as a planarizing film can be imparted to the second interlayer insulating film 42B. A plurality of pixel electrodes 35A and 35B made of ITO of 50 nm are provided through contact holes H1 and H2 formed in the second interlayer insulating film 42B and the third interlayer insulating film 43.

  On the outermost surface of the element substrate 300 configured as described above, the partition wall 13 that partitions the pixel region is formed at a predetermined height. A distance between the element substrate 300 and the counter substrate 310 is maintained by the partition wall 13.

  According to the electrophoretic display device 100 of the present embodiment, the plurality of data lines 68A and 68B are arranged at substantially equal intervals on the first substrate 30 of the element substrate 300, and a sufficient distance is secured between the wirings. Yes. As a result, short-circuit failure due to foreign matter can be prevented, destruction of the select transistors TR1 and TR2 can be prevented, and the manufacturing yield can be stabilized.

  On the data lines 68A and 68B, the connection electrodes 44A and 44B and the pixel electrodes 35A and 35B are formed so as to overlap each other in plan view. By arranging the data lines 68A and 68B inside the pixel area as compared with the conventional case, the distance between the data lines 68A and 68B of adjacent pixels is sufficiently secured.

  In the present embodiment, a plurality of dot-shaped pixel electrodes 35A and 35B are connected to each other by comb-shaped connection electrodes 44A and 44B provided on the lower layer side, and the connection electrodes 44A and 44B connect the data lines 68A and 68B. It is the composition which covers. By adopting such a configuration, the leakage of the electric field to the electrophoretic material of the data lines 68A and 68B is shielded, and there is no problem. In other words, the electric field formed by the data lines 68A and 68B leaks into the electrophoretic material of each pixel 40, so that crosstalk may occur and display quality may deteriorate. Therefore, if the above configuration is used to prevent the occurrence of crosstalk, the effect of improving the display quality is great.

[Second Embodiment]
Next, a second embodiment of the electrophoretic display device according to the invention will be described.
FIG. 9 is a plan view showing a configuration on the element substrate of the electrophoretic display device of the second embodiment, and FIG. 10 is a cross-sectional view taken along line BB of FIG.
In the following description, the description of the same configuration as in the previous embodiment is omitted, and only a different configuration will be described.
As shown in FIG. 10, the first interlayer insulating film 42A, the contact hole H3, and the connection electrode 44A of a layer different from the source / drain electrodes used in FIG. 8 are not used in the sectional view of this embodiment. The connection electrode is formed in the same layer as the drain electrode 44d. Therefore, although it can be formed with a small number of steps, the pixel electrodes 36A and 36B cannot be formed on the selection transistor TR1 (TR2).

  As shown in FIG. 9, in the electrophoretic display device of this embodiment, each of the sub-pixels S (40r, 40g, 40b) is provided with two selection transistors TR1, TR2 and two pixel electrodes 36A, 36B. ing. Here, the pixel electrodes 36A and 36B are not in the dot shape (circular shape) comb shape as in the previous embodiment, but in an L shape close to a quadrangle in plan view, and the data line 68A for each subpixel S. , 68B are arranged side by side along the extending direction.

  In this way, by forming the pixel electrode 36A, 36B into a shape that occupies substantially half the area of the sub-pixel, the proportion of the pixel electrodes 36A, 36B in the sub-pixel increases. It can be moved efficiently.

  Also in this embodiment, as in the previous embodiment, a plurality of data lines 68A and 68B are arranged at substantially equal intervals on the first substrate 30 of the element substrate 300, and each of the pixel electrodes 36A and 36B is viewed in plan view. It is formed to overlap. For this reason, the interval between the data lines 68A and 68B between the sub-pixels is set to be longer than between the pixel electrodes 36A (36B), thereby preventing a short circuit between the data lines 68A and 68B due to foreign matter. ing. As a result, it is possible to prevent the occurrence of problems such as driving elements and to stabilize the manufacturing yield.

[Third Embodiment]
Next, a third embodiment of the electrophoretic display device according to the invention will be described.
FIG. 11 is an equivalent circuit diagram showing the configuration of the electrophoretic display device of the third embodiment, and FIG. 12 is a plan view showing the pixel configuration.
In the following description, the description of the same configuration as in the first embodiment is omitted, and only a different configuration will be described.
As shown in FIG. 11, the electrophoretic display device according to the present embodiment includes two selection transistors TR1 and TR2, two pixel electrodes 56A and 56B, an electrophoretic layer 32, a common electrode 37, and two in one subpixel S. Two holding capacitors Cs are provided.

The storage capacitor Cs includes a pair of electrodes 10a and 10b arranged to face each other with a dielectric film therebetween, and the drain of the selection transistor TR1 and the connection electrode 44A are connected to one electrode 10a. The electrode 10b of the storage capacitor Cs in each subpixel is connected to a storage capacitor line 69 (FIG. 12) formed simultaneously with the gate electrodes of the selection transistors TR1 and TR2, and each is held at the same potential. The storage capacitor may be formed simultaneously with the data lines 68A and 68B.
As described above, by adding the storage capacitor Cs in each sub-pixel S, the voltage applied to the pixel electrodes 56A and 56B is not easily attenuated, and the particles can be moved in a short time.

  Further, as shown in FIG. 12, the pixel electrodes 56A and 56B of the present embodiment are configured to have a comb-teeth shape in plan view. The pixel electrodes 56A and 56B include a trunk portion 561 connected to the drains of the selection transistors TR1 and TR2 through contact holes H1 and H2, and a plurality of branch portions 562a and 562b connected by the trunk portion 561. . The pixel electrodes 56A and 56B are disposed in the sub-pixel S so as to engage with each other.

  A storage capacitor Cs (FIG. 11) is formed in a region where the branch portions 562a and 562b of the pixel electrodes 56A and 56B and the storage capacitor line 69 overlap. The storage capacitor line 69 is partially narrowed at the intersections with the data lines 68A and 68B. By making the area overlapping with the data lines 68A and 68B as small as possible, the capacitive load at the intersection with the data lines 68A and 68B can be suppressed.

[Fourth Embodiment]
Next, a fourth embodiment of the electrophoretic display device according to the invention will be described.
FIG. 13 is a plan view showing a pixel configuration of the electrophoretic display device of the fourth embodiment.
As shown in FIG. 13, the present embodiment is different from the previous embodiment in that the scanning line 76 is not branched in the display area.
The scanning line 76 extends so as to pass through the central portion of each sub-pixel S. A pair of selection transistors TR1 and TR2 provided in each sub-pixel S are connected to a common scanning line 67 in the sub-pixel S, whereby the operations of the selection transistors TR1 and TR2 are synchronized and turned on at the same time. Or it will be in an OFF state.

  A plurality of data lines 68A and 68B are arranged at substantially equal intervals so as to cross the scanning line 67, and when a certain scanning line 76 is selected, a predetermined number of data lines 68A are selected from the data line 68A via the selection transistor TR1. Is supplied to the pixel electrode 75A (first electrode), and a predetermined potential is supplied from the data line 68B to the pixel electrode 75B (second electrode) via the selection transistor TR2.

  The pixel electrodes 75A and 75B of the present embodiment have a square shape in plan view, and cover the select transistors TR1 and TR2 and partially cover the data lines 68A and 68B.

  If there are two scanning lines in the sub-pixel, the occupied area increases as compared to one scanning line, and the aperture ratio decreases. Therefore, in the present embodiment, the scanning lines 76 passing through the sub-pixels S are combined into one. Furthermore, since the data lines 68A and 68A are also arranged at substantially equal intervals, both the scanning line 76 and the data lines 68A and 68B are prevented from being short-circuited due to foreign matter and the like, thereby improving product performance and manufacturing yield. More stable.

[Fifth Embodiment]
Next, a fifth embodiment of the electrophoretic display device according to the invention will be described.
FIG. 14 is a plan view showing the pixel configuration of the electrophoretic display device of the fifth embodiment, and FIG. 15 is a cross-sectional view taken along the line CC of FIG.
In each of the previous embodiments, two pixel electrodes are provided for each pixel. However, the present embodiment is different from the previous embodiment in that one pixel electrode functions as a partition wall.

As shown in FIG. 14, each sub-pixel S of the present embodiment includes a pair of selection transistors TR1 and TR2, a pixel electrode 85 (first electrode), and a conductive partition wall 83 (second electrode) having conductivity. ) And are provided.
The drain electrode 41d (FIG. 15) of the selection transistor TR1 is connected to a frame-shaped conductive partition wall 83 that partitions the pixel region, and the potential from the data line 68A is supplied to the conductive partition wall 83 via the selection transistor TR1. It has come to be.

  The drain electrode of the selection transistor TR2 is connected to a pixel electrode 85 formed in substantially the entire pixel area (excluding the formation area of the selection transistor TR2) partitioned by the conductive partition wall 83. Then, the potential from the data line 68B is supplied to the pixel electrode 85 via the selection transistor TR2.

  As shown in FIG. 15, the conductive partition wall 83 is configured by overlapping an insulating film 83B made of an insulating acrylic material not containing carbon on a conductive portion 83A made of conductive photosensitive acrylic resin containing carbon. Yes. Since the conductive partition 83 disposed between the substrates 30 and 31 is in contact with the common electrode 37, it is formed using an insulating material. A contact portion with the drain electrode of the select transistor TR1 is formed of a conductive acrylic resin. The film thickness of the conductive partition 83 is 50 μm.

  The pixel electrode 85 is formed at a distance from the conductive partition wall 83 at a position not overlapping the conductive partition wall 83 in plan view. The reason for this configuration is to avoid a short circuit with the conductive partition wall 83.

  Also in the present embodiment, the plurality of data lines 68A and 68B are arranged at substantially equal intervals on the first substrate 30 on the element substrate 300 side, but only the one data line 68B side is flat with the conductive partition wall 83. It is formed in a position that overlaps visually.

  According to the configuration of the present embodiment, different potentials can be supplied to the pixel electrode 85 and the conductive partition wall 83, respectively. Thereby, particles charged to an arbitrary polarity move between the pixel electrode 85, the common electrode, and the conductive partition wall 83. That is, since particles charged to an arbitrary polarity can be adsorbed to the conductive partition wall 83 side, light color display (intermediate gradation) is also possible.

  The insulating film 83B forming the conductive partition wall 83 is not limited to an acrylic material, and other insulating materials can be used. Further, for example, a material other than carbon-containing acrylic may be used for the conductive portion 83A.

[Sixth Embodiment]
Next, a sixth embodiment of the electrophoretic display device according to the invention will be described.
FIG. 16 is a plan view showing a pixel configuration of the electrophoretic display device of the sixth embodiment.
The difference between this embodiment and the previous embodiment is that no partition is provided. In addition, the pixel electrode 95A (first pixel electrode) and the pixel electrode 95B (second pixel electrode) of the present embodiment have six branch portions 952a and 952b, respectively, and are arranged so as to engage with each other. The data lines 68A and 68B arranged at equal intervals on the first substrate 30 of the element substrate 300 are formed so as to overlap with one of the plurality of branch portions 952a and 952b of the pixel electrodes 95A and 95B in plan view. Yes.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

For example, the partition described in the previous embodiment has a function of separating the sub-pixels S and a function of maintaining the distance between the element substrate 300 and the counter substrate 310. The method for realizing this purpose is not limited to the partition wall. For example, when it is not necessary to divide into sub-pixels as in the case of black-and-white display, or in the case of a structure in which multi-coloring is performed with one pixel, a space between the substrates may be secured using columnar spacers.
A capsule type electrophoretic material may also be used.

  Further, as a semiconductor constituting the selection transistor, an oxide semiconductor other than the above, amorphous Si, poly-Si, or an organic semiconductor may be used. The selection transistor may have a top gate structure instead of a bottom gate.

  Further, the insulating material (substrate, gate insulating film, interlayer insulating film, partition wall) and wiring material are not limited to the above. For example, another inorganic material or an organic material such as polyimide may be used as the insulating material. Further, other metal or organic material, transparent conductive material silicide, conductive paste or the like may be used as the pixel electrode and wiring material.

  Further, since the interlayer insulating film is formed by a coating method, it also serves as a planarizing film.

  The pixel electrode 35 may have a two-layer structure of metal and ITO.

  In the previous embodiment, black and white three particles were shown as the electrophoretic material. However, in other subpixels, three black and white particles and three black and white particles may be used. The selection of which of these three particles to be plus, minus, or uncharged particles is not limited to the above example. Further, the combination of the colors of the three particles can be other than the above. For example, white red cyan, white green magenta, and white blue yellow may be used.

  Further, the electrophoretic display device may be constituted by only a three-particle system of black and white and not color. At this time, red display is possible in addition to black and white display.

  Further, in the present invention, it is fundamental to control the positively and negatively charged particles with two selection transistors. Therefore, the electrophoretic material can be applied not as a three-particle system but as a combination of two particles charged positively and negatively and a dispersion medium holding the two particles. The dispersion medium may be colored or colorless and transparent, and can be appropriately used depending on the purpose and configuration.

In the second embodiment, a pair of pixel electrodes 36A and 36B are arranged in one subpixel S along the extending direction of the data lines 68A and 68B. For example, as shown in FIG. The lines 66 may be arranged along the extending direction.
In each embodiment, a liquid dispersion medium is used, but the dispersion medium may be a gas.

[Electronics]
Next, a case where the electrophoretic display device of each of the above embodiments is applied to an electronic device will be described.
FIG. 18 is a perspective view illustrating a specific example of an electronic apparatus to which the electrophoretic display device of the present invention is applied.
FIG. 18A is a perspective view illustrating an electronic book which is an example of the electronic apparatus. The electronic book 1000 includes a book-shaped frame 1001, a cover 1002 that can be rotated (openable and closable) with respect to the frame 1001, an operation unit 1003, and the electrophoretic display device of the present invention. Display unit 1004.

  FIG. 18B is a perspective view illustrating a wrist watch that is an example of an electronic apparatus. The wristwatch 1100 includes a display unit 1101 configured by the electrophoretic display device of the present invention.

  FIG. 18C is a perspective view illustrating electronic paper which is an example of an electronic apparatus. This electronic paper 1200 includes a main body portion 1201 formed of a rewritable sheet having the same texture and flexibility as paper, and a display portion 1202 formed of an electrophoretic display device of the present invention.

For example, electronic books, electronic papers, and the like are supposed to be used for repeatedly writing characters on a white background, and therefore it is necessary to eliminate afterimages at the time of erasure and afterimages over time.
Note that the range of electronic devices to which the electrophoretic display device of the present invention can be applied is not limited to this, and includes a wide range of devices that utilize changes in visual color tone accompanying the movement of charged particles.

  According to the electronic book 1000, the wristwatch 1100, and the electronic paper 1200 described above, since the electrophoretic display device according to the present invention is employed, the electronic device includes color display means.

  In addition, said electronic device illustrates the electronic device which concerns on this invention, Comprising: The technical scope of this invention is not limited. For example, the electrophoretic display device according to the present invention can be suitably used for a display portion of an electronic device such as a mobile phone or a portable audio device.

DESCRIPTION OF SYMBOLS 100 Electrophoretic display apparatus, 5 Display part, 13 Partition, 21 Dispersion medium, 26 Negative charged particle, 27 Positive charged particle, 28 Uncharged particle, 30 1st board | substrate, 31 2nd board | substrate, 32 Electrophoretic layer, 35A, 36A 75A, 85, 95A Pixel electrode (first electrode), 35B, 36B, 75B, 95B Pixel electrode (second electrode), 37 Common electrode (third electrode), 40 pixels, S, 40r, 40g, 40b Subpixel 41b Gate insulating film, 42 1st interlayer insulating film, 42A 1st interlayer insulating film, 42B 2nd interlayer insulating film, 43 2nd interlayer insulating film, 44 connection electrode, 44A connection electrode (first connection electrode), 44B connection Electrode (second connection electrode), 56A Pixel electrode, 61 Scan line drive circuit, 62 Data line drive circuit, 66, 66A, 66B, 67, 76 Scan line, 68A Data line (first data line), 68 Data line (second data line), 69 storage capacitor line, 83, 83A conductive partition wall (second electrode, partition wall) 83B insulating film, Cs storage capacitor, 100 electrophoretic display device, 300 element substrate, 310 counter substrate, TR1 Selection transistor (first transistor), TR2 Selection transistor (second transistor), 1000 Electronic book (electronic device), 1100 Watch (electronic device), 1200 Electronic paper (electronic device)

Claims (14)

A first substrate and a second substrate;
An electrophoretic layer disposed between the first substrate and the second substrate and having at least a dispersion medium and a plurality of particles mixed in the dispersion medium;
A first electrode and a second electrode which are formed for each pixel on the electrophoretic layer side of the first substrate and are driven independently of each other;
A third electrode having a larger area than the total area of the first electrode and the second electrode formed on the electrophoretic layer side of the second substrate;
A first data line connected to the first electrode via a first transistor;
A second data line connected to the second electrode via a second transistor;
A plurality of scanning lines extending in a direction intersecting the first data line and the second data line,
A plurality of the first data lines and the second data lines, and the first data lines and the second data lines are alternately arranged in one direction;
The interval between the first data line and the second data line adjacent to each other is such that the first electrodes adjacent to each other in the arrangement direction of the first data line and the second data line, the second electrodes, or the second data line. An electrophoretic display device characterized by being wider than the interval between one electrode and the second electrode.   2. The electrophoretic display device according to claim 1, wherein the first data line and the second data line are arranged at equal intervals.   The electrophoresis according to claim 1, wherein the first data line or the second data line overlaps at least one of the first electrode and the second electrode in a plan view. Display device. The plurality of first electrodes included in one pixel are connected to each other by a first connection electrode formed on the first substrate side than the first electrode,
The plurality of second electrodes included in one pixel are connected to each other by a second connection electrode formed on the first substrate side with respect to the second electrode. The electrophoretic display device according to any one of 3. The first connection electrode is formed on the first data line;
The electrophoretic display device according to claim 4, wherein the second connection electrode is formed on the second data line.   The electrophoretic display device according to claim 1, wherein the first electrode and the second electrode are formed in a comb shape or an island shape.   5. The electrophoretic display device according to claim 1, wherein the first electrode or the second electrode functions as a partition that partitions the pixel. 6.   The electrophoretic display device according to claim 7, wherein the partition is formed on the first data line or the second data line.   The partition that holds the distance between the first substrate and the second substrate is composed of a conductive portion connected to the first transistor or the second transistor and an insulating film that covers a surface of the conductive portion. The electrophoretic display device according to claim 7 or 8.   A scanning line extending in a direction crossing the first data line and the second data line is branched into two in the display region, one of the branch portions is connected to the first transistor, and the other is connected to the second transistor. The electrophoretic display device according to claim 1, wherein the electrophoretic display device is connected to a transistor.   A scanning line extending in a direction intersecting the first data line and the second data line is disposed so as to pass through the center of the pixel, and the first transistor and the second transistor are connected to the scanning line. An electrophoretic display device according to claim 1, wherein:   12. The dispersion medium according to claim 1, wherein the particles of the first color positively charged and the particles of the second color negatively charged are contained. The electrophoretic display device according to item.   The electrophoretic display device according to claim 12, wherein the dispersion medium further includes the non-charged third color particles.   An electronic apparatus comprising the electrophoretic display device according to claim 1.

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