JP6010921B2 - Electro-optical device control method, electro-optical device control device, electro-optical device, and electronic apparatus - Google Patents

Description

  The present invention relates to a control method for an electro-optical device such as an electrophoretic display device, a control device for the electro-optical device, an electro-optical device, and an electronic device.

  As an example of this type of electro-optical device, a voltage is applied between a pixel electrode and an opposing electrode that are opposed to each other with an electrophoretic element including electrophoretic particles interposed therebetween, and electrophoretic particles such as black particles and white particles are moved. Thus, there is an electrophoretic display device that displays an image on a display unit. The electrophoretic element is composed of, for example, a plurality of microcapsules each including a plurality of electrophoretic particles, and is fixed between the pixel electrode and the counter electrode by an adhesive made of resin or the like. The counter electrode is sometimes called a common electrode.

  In such an electrophoretic display device, for example, white can be displayed by applying a voltage that moves white particles to the display surface side, and black by applying a voltage that moves black particles to the display surface side. Can be displayed. Further, by adjusting the period during which each voltage corresponding to white and black described above is applied, it is possible to display white and black intermediate gradations (that is, gray) (for example, Patent Documents). 1 to 3).

US Patent Application Publication No. 2005/0001812 US Patent Application Publication No. 2005/0280626 International Publication No. 2005/101363

  When displaying an intermediate gradation, each particle may be moved to an intermediate position when white and black are displayed. However, such control is not easy. For example, if the position of each particle varies, the displayed gradation may also vary. In particular, when a plurality of intermediate gradations are displayed, the above-described variation on the display image has a great influence.

  On the other hand, for example, when changing the gradation from light gray (that is, gray near white) to dark gray (that is, gray near black), white or black is once displayed from the state where light gray is displayed. If each particle is moved to a position where it is moved and then moved to a position where dark gray is displayed, the positions of the particles for each pixel can be aligned, and an intermediate gradation can be displayed suitably. .

  As described above, when displaying an intermediate gradation, it may be required to apply voltages having different polarities in a plurality of phases. However, when a plurality of phases are executed in a plurality of pixels, voltages having different polarities may be applied to adjacent pixels. For example, when a negative voltage corresponding to white is applied to one pixel, a situation where a sex voltage corresponding to black is applied to another adjacent pixel may occur.

  Here, according to the research conducted by the present inventor, when voltages having different polarities are applied to adjacent pixels, the influence of the transverse electric field between the pixels increases, and as a result, the display image may be disturbed. It turns out that there is. However, each of the above-mentioned patent documents does not describe any measures for a period in which voltages having different polarities are applied to adjacent pixels. In other words, the related art including the above-described patent documents has a technical problem that the image quality may be deteriorated due to the influence of the lateral electric field between adjacent pixels.

  The present invention has been made in view of the above-described problems, for example, and is a method for controlling an electro-optical device capable of suitably displaying intermediate gray levels while reducing the influence of a lateral electric field between adjacent pixels. It is an object of the present invention to provide an electro-optical device control device, an electro-optical device, and an electronic apparatus.

  In order to solve the above problems, a control method for an electro-optical device according to the present invention is provided corresponding to the intersection of a plurality of scanning lines and a plurality of data lines intersecting each other, and between a pixel electrode and a counter electrode facing each other. A plurality of pixels each having an electro-optic material, wherein the pixels are a first limit optical state, a second limit optical state, and a plurality of pixels between the first limit optical state and the second limit optical state; A display unit capable of taking an intermediate optical state, and a voltage pulse corresponding to the image data is applied to the pixel electrode of each of the plurality of pixels in a plurality of frames in order to display an image corresponding to the image data on the display unit. A control method for controlling an electro-optical device including a driving unit that supplies a period of time, wherein a control step when shifting a first pixel among the plurality of pixels to a first intermediate optical state is the first method. One pixel A first control step for supplying a first voltage pulse to the pixel electrode, and a reverse of the first voltage pulse for the pixel electrode of the first pixel after the first control step. A second control step of supplying a second voltage pulse having a polarity, and a control step for shifting a second pixel adjacent to the first pixel to a second intermediate optical state includes the second control step. A third control step of supplying a third voltage pulse having the same polarity as the first voltage pulse to the pixel electrode of the pixel; and after the third control step, the pixel electrode of the second pixel In contrast, a fourth control step of supplying a fourth voltage pulse having the same polarity as the second voltage pulse, a period during which the first control step is performed, and a period during which the fourth control step is performed, or The period during which the second control step is performed and the period during which the third control step is performed are mutually different. As opposite polarity period becomes shorter overlap, with respect to the pixel electrode of the second pixel, and a fifth control step of supplying at least one frame period fifth voltage pulse of the counter electrode at the same potential.

  An electro-optical device controlled by the control method for an electro-optical device according to the present invention includes a display unit having a plurality of pixels arranged in a matrix corresponding to intersections of a plurality of scanning lines and a plurality of data lines. ing. The display unit includes an electro-optical material between the pixel electrode and the counter electrode facing each other. In addition, the plurality of pixels in the display unit have a first limit optical state, a second limit optical state, and a plurality of intermediate optical states between the first limit optical state and the second limit optical state. Is possible.

  Here, the “ultimate optical state” is an optical state realized by sufficiently applying a predetermined voltage to the electro-optical material in the display unit. However, the `` extreme optical state '' according to the present invention not only means a state in which the optical state does not change at all even when a predetermined voltage is applied, but for example, a plurality of pixels are simultaneously in the extreme optical state, This is a broad concept including an optical state in which the optical state of each pixel can be aligned to such an extent that variations in the optical state between pixels can be reduced. Specifically, for example, when the electro-optical material is configured as an electrophoretic element including white particles and black particles, white or black that is displayed when the white particles are sufficiently attracted to the display surface side. The optical state when displaying black that is displayed by sufficiently attracting the particles to the display surface side corresponds to the “extreme optical state” according to the present invention.

  The “intermediate optical state” means an intermediate optical state between the first extreme optical state and the second extreme optical state. For example, the above-described optical state when displaying white and black is the extreme optical state. In the case of the state, the optical state when displaying gray corresponds. The “intermediate optical state” is, for example, by adjusting a period for applying a voltage for changing the optical state to the first extreme optical state or a voltage for changing the optical state to the second extreme optical state. Realized. More specifically, for example, the gray of the intermediate optical state is displayed by moving the positions of white particles and black particles included in the electrophoretic element to an intermediate position when displaying white and black. Can do.

  In the display unit according to the present invention, each pixel can have a plurality of intermediate optical states such as light gray and dark gray. Such a plurality of intermediate optical states can be displayed by adjusting the position of each particle between the pixel electrode and the counter electrode. Specifically, by setting white particles to an intermediate position relatively close to the display surface side (or black particles to an intermediate position relatively far from the display surface side), light gray can be displayed. The dark gray color can be displayed by setting the particles at an intermediate position relatively far from the display surface side (or by setting the black particles at an intermediate position relatively close to the display surface side).

  The display unit described above is controlled by the drive unit to display an image corresponding to the image data. Specifically, during the operation of the electro-optical device according to the present invention, a voltage pulse corresponding to image data is supplied to each pixel electrode of the plurality of pixels by the driving unit. As a result, a voltage corresponding to the image data is applied to each pixel, and an image corresponding to the image data is displayed on the display unit.

  Note that the supply of the voltage pulse to each pixel by the driving unit is performed over a plurality of frame periods. In other words, the voltage is applied to the pixels of the display portion a plurality of times in units of frame periods. Specifically, during one frame period, a plurality of scanning lines are selected once in a predetermined order, and a voltage pulse is applied to a pixel electrode in a pixel corresponding to the selected scanning line. Supplied through. Here, the “frame period” is a period set in advance as a period for selecting a plurality of scanning lines once in a predetermined order. That is, in each of a plurality of consecutive frame periods, control for supplying a voltage pulse to the pixel electrode in each of the plurality of pixels is performed once, whereby an image corresponding to the image data is displayed on the display unit.

  According to the control method of the electro-optical device according to the present invention, the first control step and the second control step are sequentially performed when the first pixel is shifted to the first intermediate optical state. Here, the “first intermediate optical state” is an intermediate optical state targeted in the rewriting of the first pixel, and any one of a plurality of intermediate optical states that can be taken by the pixel of the display unit. Set as state.

  In the first control step, the first voltage pulse is supplied to the pixel electrode of the first pixel. In the subsequent second control step, a second voltage pulse having a polarity opposite to that of the first voltage pulse is supplied to the pixel electrode of the first pixel. For example, when a voltage pulse corresponding to a first limit optical state (for example, white) is supplied in the first control step, a voltage pulse corresponding to a second limit optical state (for example, black) is supplied in the second control step. Is supplied. According to the first control process and the second control process, voltages having different polarities are sequentially applied to the first pixel, and the first intermediate optical state can be preferably realized.

  On the other hand, according to the control method of the electro-optical device according to the present invention, the third control step and the fourth control are performed when the second pixel adjacent to the first pixel is shifted to the second intermediate optical state. The steps are performed sequentially. Note that the “second intermediate optical state” here is an intermediate optical state targeted in the rewriting of the second pixel, similar to the above-described first intermediate optical state, and the pixel of the display unit takes the state. One of the plurality of intermediate optical states to be obtained is set as an optical state. Note that the first intermediate optical state and the second intermediate optical state may be the same intermediate optical state.

  In the third control step, a third voltage pulse having the same polarity as the first voltage pulse (that is, the voltage pulse supplied to the first pixel in the first control step) is applied to the pixel electrode of the second pixel. Is supplied. In the subsequent fourth control step, a fourth voltage having the same polarity as the second voltage pulse (that is, the voltage pulse supplied to the first pixel in the second control step) is applied to the pixel electrode of the second pixel. Voltage pulses are supplied. For example, a voltage pulse corresponding to the first extreme optical state (for example, white) is supplied in the first control step, and a voltage pulse corresponding to the second limit optical state (for example, black) is supplied in the second control step. If so, a voltage pulse corresponding to the first limit optical state is supplied in the third control step, and a voltage pulse corresponding to the second limit optical state is supplied in the fourth control step. According to the third control process and the fourth control process, voltages having different polarities are sequentially applied to the second pixel, and the second intermediate optical state can be preferably realized.

  Here, the first control process and the second control process (that is, control for the first pixel) and the third control process and the fourth control process (that is, control for the second pixel) described above are started. Timing and the number of frame periods in each process may be different from each other. Therefore, the first and third control steps for supplying the first voltage pulse and the third voltage pulse having the same polarity to the first pixel and the second pixel, respectively, and the first pixel. The second control step and the fourth control step for supplying the second voltage pulse and the fourth voltage pulse having the same polarity to each of the second pixels can be performed at timings independent of each other. Accordingly, a period in which the first control process and the fourth control process are performed simultaneously and a period in which the second control process and the third control process are performed simultaneously (that is, voltages having different polarities are applied to the first pixel and the second pixel). Applied reverse polarity period) may occur.

  In particular, according to the present inventors' research, when a reverse polarity period occurs in which voltages having different polarities are applied to the first pixel and the second pixel, the first pixel and the second pixel are generated. It has been found that the influence of the horizontal electric field increases and the display image is disturbed (that is, the optical state to be realized cannot be accurately realized). In particular, when the reverse polarity period occurs near the end of the rewrite period, adjustment by subsequent rewrite is difficult, so that the influence of the lateral electric field appears greatly. Therefore, it is preferable that the reverse polarity period is not generated or is as short as possible even if it occurs.

  On the other hand, according to the present invention, in the fifth control step, the pixel electrode of the second pixel is reduced so that the reverse polarity period in which voltages having different polarities are applied to the first pixel and the second pixel is reduced. Thus, the fifth voltage pulse having the same potential as that of the counter electrode is supplied for at least one frame period. That is, the fifth control process adjusts the rewrite period (that is, the period during which the third control process and the fourth control process are performed) for the second pixel, and shortens the reverse polarity period. More specifically, the first control process and the third control process or the second control process and the fourth control process in which voltage pulses of the same polarity are supplied to the first pixel and the second pixel are as close as possible to each other. As a result, the reverse polarity period is shortened. Therefore, an increase in the influence of the transverse electric field due to the reverse polarity period can be reduced, and display disturbance can be suppressed.

  The timing at which the fifth control step is performed is not particularly limited, and may be performed at any timing as long as the above-described reverse polarity period can be shortened. Further, the period during which the fifth control step is performed (that is, the frame period in which the fifth voltage pulse having the same potential as the counter electrode is supplied to the pixel electrode of the second pixel) is, for example, the first control step and the third control. It can be set as a difference between frame periods in which processes are performed, or as a difference between frame periods in which the second control process and the fourth control process are performed.

  As described above, according to the control method of the electro-optical device according to the present invention, the influence of the lateral electric field between the adjacent pixels is reduced by setting the fifth control step for shortening the reverse polarity period. Therefore, it is possible to display the intermediate gradation suitably. As a result, a high quality image can be displayed.

  In one aspect of the electro-optical device control method according to the present invention, the fifth control step is performed before the third control step.

  According to this aspect, the start timing of the third control process can be delayed by the period of the fifth control process. Therefore, for example, the third control process for the second pixel is completed earlier than the first control process for the first pixel, and the first control process and the fourth control process following the third control process are greatly overlapped. Can be prevented. Accordingly, the reverse polarity period in which voltages having different polarities are applied to the first pixel and the second pixel can be reliably shortened.

  In the aspect in which the above-described fifth control process is performed before the third control process, the fifth control process has a timing at which the first control process ends and a timing at which the third control process ends. As described above, a frame period for supplying the fifth voltage pulse may be set.

  In this case, since the timing at which the first control step for the first pixel ends and the timing at which the third control step for the second pixel ends are aligned with each other, for example, the first control in which the polarity of the applied voltage is different from each other. It can prevent that a process and a 4th control process overlap. Accordingly, it is possible to eliminate a reverse polarity period in which voltages having different polarities are applied to the first pixel and the second pixel.

  In another aspect of the method for controlling an electro-optical device according to the present invention, the fifth control step is performed between the third control step and the fourth control step.

  According to this aspect, the start timing of the fourth control process can be delayed by the period of the fifth control process. Therefore, for example, the fourth control process for the second pixel is started earlier than the second control process for the first pixel, and the first control process and the fourth control process following the third control process are greatly overlapped. Can be prevented. Accordingly, the reverse polarity period in which voltages having different polarities are applied to the first pixel and the second pixel can be reliably shortened.

  In the aspect in which the fifth control process described above is performed between the third control process and the fourth control process, the fifth control process starts with the timing at which the second control process starts and the fourth control process. The frame period for supplying the fifth voltage pulse is set so that the timing is aligned with each other.

  In this case, since the timing at which the second control process for the first pixel is started and the timing at which the fourth control process for the second pixel is started are aligned with each other, for example, the polarities of the applied voltages are different from each other. It can prevent that 1 control process and 4th control process overlap. Accordingly, it is possible to eliminate a reverse polarity period in which voltages having different polarities are applied to the first pixel and the second pixel.

  In another aspect of the method for controlling an electro-optical device according to the present invention, the first control step includes the first control step until the first extreme optical state is reached with respect to the pixel electrode of the first pixel. The second control step supplies the second pulse so as to approach the first intermediate optical state to the pixel electrode of the first pixel. And the third control step is a step of supplying the third voltage pulse to the pixel electrode of the second pixel until the first extreme optical state is reached. The fourth control step is a step of supplying the fourth pulse to the pixel electrode of the second pixel so as to approach the second intermediate optical state.

  According to this aspect, in the first control step, the first voltage pulse corresponding to the first limit optical state (for example, white) is supplied to the pixel electrode of the first pixel. Thereby, the first pixel is in the first limit optical state. As described above, the optical state between the plurality of pixels in the display unit can be made uniform by temporarily setting the ultimate optical state before setting the first pixel to the target first intermediate optical state. Specifically, for example, the positions of the particles included in the electrophoretic element can be aligned. Therefore, when the pixel is shifted to the intermediate optical state, it is possible to prevent noise or the like from being generated in the displayed image due to variations in the optical state among the plurality of pixels.

  In the second control step, the second voltage pulse corresponding to the second extreme optical state (for example, black) is supplied to the pixel electrode of the first pixel. Thereby, the optical state in the first pixel is brought close to the first intermediate optical state. Note that another control process for finely adjusting the optical state of the first pixel may be set after the second control process.

  On the other hand, in the third control step, as in the first control step described above, the third voltage pulse corresponding to the first extreme optical state is supplied to the pixel electrode of the second pixel. Thereby, the second pixel is in the first limit optical state.

  In the fourth control step, as in the second control step described above, the fourth voltage pulse corresponding to the second limit optical state is supplied to the pixel electrode of the second pixel. Thereby, the optical state in the second pixel is brought close to the second intermediate optical state. Note that another control process for finely adjusting the optical state of the second pixel may be set after the fourth control process.

  According to the first control process and the second control process for the first pixel and the third control process and the fourth control process for the second pixel described above, voltages having different polarities are sequentially applied to the pixels. Thus, the target intermediate optical state (that is, the first intermediate optical state and the second intermediate optical state) can be preferably realized.

  However, since voltages having different polarities are applied, reverse polarity periods as described above may also occur. In contrast, in this aspect, in the fifth control step, the pixel electrode of the second pixel is reduced so that the reverse polarity period in which voltages having different polarities are applied to the first pixel and the second pixel is reduced. Thus, the fifth voltage pulse having the same potential as that of the counter electrode is supplied for at least one frame period. Therefore, the reverse polarity period can be shortened, and the display image can be prevented from being disturbed due to an increase in the influence of the lateral electric field.

  In another aspect of the method for controlling an electro-optical device according to the present invention, the first control step may be performed with respect to the pixel electrode of the first pixel rather than the first intermediate optical state. The step of supplying the first voltage pulse from the previous optical state to the far intermediate optical state, wherein the second control step applies the first voltage to the pixel electrode of the first pixel. Supplying the second voltage pulse until the intermediate optical state is reached, wherein the third control step is performed on the pixel electrode of the second pixel more than in the second intermediate optical state. The step of supplying the third voltage pulse from the optical state before the third control step to the far intermediate optical state, wherein the fourth control step is for the pixel electrode of the second pixel, The fourth voltage until reaching the second intermediate optical state; It is a step of supplying a pulse.

  According to this aspect, in the first control step, the voltage pulse corresponding to, for example, the second extreme optical state (for example, black) is supplied to the pixel electrode of the first pixel, whereby the first The first pixel that was in an optical state closer to the first limit optical state than the intermediate optical state is set to an intermediate optical state farther from the optical state before the first control step than the target first intermediate optical state. . In other words, the optical state of the first pixel is controlled toward the first intermediate optical state, but the first pixel is in an intermediate optical state that exceeds the first intermediate optical state. The first control step is not performed intentionally so as not to be in the first intermediate optical state. For example, even when a voltage is applied in a minimum unit (that is, one frame), This is performed when the optical state changes greatly and the first intermediate optical state cannot be realized.

  In the second control step, a voltage pulse corresponding to, for example, the first limit optical state (for example, white) is supplied to the pixel electrode of the first pixel, so that the second control step is performed in the second intermediate optical state. The first pixel that is in a state close to the ultimate optical state is brought closer to the target first intermediate optical state. That is, in the first control step, the amount that has moved away from the first intermediate optical state is adjusted in the second control step.

  On the other hand, in the third control step, as in the first control step described above, for example, a voltage pulse corresponding to the second extreme optical state is supplied to the pixel electrode of the second pixel, whereby the second control step. The second pixel, which is in the optical state closer to the first limit optical state than the intermediate optical state, is set to an intermediate optical state farther from the optical state before the third control step than the target second intermediate optical state. The

  In the fourth control step, for example, a voltage pulse corresponding to the first limit optical state is supplied to the pixel electrode of the second pixel, so that the second limit optical state is changed from the second intermediate optical state. The second pixel in the close state is brought close to the target second intermediate optical state.

  According to the first control process and the second control process for the first pixel and the third control process and the fourth control process for the second pixel described above, voltages having different polarities are sequentially applied to the pixels. Thus, the target intermediate optical state (that is, the first intermediate optical state and the second intermediate optical state) can be preferably realized.

  However, since voltages having different polarities are applied, reverse polarity periods as described above may also occur. In contrast, in this aspect, in the fifth control step, the pixel electrode of the second pixel is reduced so that the reverse polarity period in which voltages having different polarities are applied to the first pixel and the second pixel is reduced. Thus, the fifth voltage pulse having the same potential as that of the counter electrode is supplied for at least one frame period. Therefore, the reverse polarity period can be shortened, and the display image can be prevented from being disturbed due to an increase in the influence of the lateral electric field.

In order to solve the above problems, a control device for an electro-optical device according to the present invention is provided corresponding to the intersection of a plurality of scanning lines and a plurality of data lines intersecting each other, and between a pixel electrode and a counter electrode facing each other A plurality of pixels each having an electro-optic material, wherein the pixels are a first limit optical state, a second limit optical state, and a plurality of pixels between the first limit optical state and the second limit optical state; A display unit capable of taking an intermediate optical state, and a voltage pulse corresponding to the image data is applied to the pixel electrode of each of the plurality of pixels in a plurality of frames in order to display an image corresponding to the image data on the display unit. A control device that controls an electro-optical device including a drive unit that supplies the period, and when the first pixel among the plurality of pixels is shifted to the first intermediate optical state,
First control means for supplying a first voltage pulse to the pixel electrode of the first pixel; and after the first voltage pulse is supplied by the first control means, the first pixel Second control means for supplying a second voltage pulse having a polarity opposite to that of the first voltage pulse to the pixel electrode, and a second pixel adjacent to the first pixel as a second intermediate optical element. A third control means for supplying a third voltage pulse having the same polarity as the first voltage pulse to the pixel electrode of the second pixel when the state is shifted to a state; Fourth control means for supplying a fourth voltage pulse having the same polarity as the second voltage pulse to the pixel electrode of the second pixel after the third voltage pulse is supplied; A period during which the first voltage pulse is supplied by the first control means; and The period in which the fourth voltage pulse is supplied by the fourth control means, or the period in which the second voltage pulse is supplied by the second control means and the third voltage pulse by the third control means. A fifth voltage pulse for supplying a fifth voltage pulse having the same potential as that of the counter electrode to the pixel electrode of the second pixel for at least one frame period so that a reverse polarity period in which the supplied periods overlap with each other is shortened; Control means.

  According to the control device for an electro-optical device according to the present invention, in the same manner as the control method for the electro-optical device according to the present invention described above, while reducing the influence of a lateral electric field between adjacent pixels in the electro-optical device, An intermediate gray level can be displayed suitably. As a result, a high quality image can be displayed.

  The electro-optical device control apparatus according to the present invention can also adopt various aspects similar to the various aspects of the electro-optical device control method according to the present invention described above.

  In order to solve the above problems, an electro-optical device according to the present invention includes the above-described electro-optical device control device according to the present invention (including various aspects thereof).

  According to the electro-optical device according to the present invention, since the electro-optical device control device according to the present invention described above is provided, a desired intermediate optical state can be suitably obtained while preventing variations in the optical state among a plurality of pixels. Can be realized. As a result, a high quality image can be displayed.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention (including various aspects thereof).

  The electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention, so that a high-quality image can be displayed, for example, a wristwatch, electronic paper, an electronic notebook, a mobile phone, and a portable device. Various electronic devices such as audio devices can be realized.

  The effect | action and other gain of this invention are clarified from the form for implementing invention demonstrated below.

1 is a block diagram illustrating an overall configuration of an electrophoretic display device according to an embodiment. It is a block diagram which shows the structure of the display part periphery of the electrophoretic display device which concerns on embodiment. It is an equivalent circuit diagram which shows the electrical structure of the pixel which concerns on embodiment. It is a fragmentary sectional view of the display part of the electrophoretic display device concerning an embodiment. It is a flowchart which shows the control method of the electrophoretic display device which concerns on embodiment. It is a conceptual diagram which shows generation | occurrence | production of the reverse polarity period in the adjacent pixel which concerns on 1st Embodiment. It is a conceptual diagram which shows the voltage application method after the phase Z setting. It is a graph which shows the change of the gradation at the time of rewriting from white to black. It is a graph which shows the change of the gradation at the time of rewriting from black to white. It is a conceptual diagram which shows generation | occurrence | production of the reverse polarity period in the adjacent pixel which concerns on 2nd Embodiment. It is a conceptual diagram which shows the voltage application method after phase Z0 and Z1 setting. It is a perspective view which shows the structure of the electronic paper which is an example of the electronic device to which the electro-optical device is applied. It is a perspective view which shows the structure of the electronic notebook which is an example of the electronic device to which the electro-optical apparatus is applied.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Electro-optical device>
The electro-optical device according to this embodiment will be described with reference to FIGS. In the following embodiments, an active matrix driving type electrophoretic display device will be described as an example of the electro-optical device according to the invention.

  First, the overall configuration of the electrophoretic display device according to the present embodiment will be described with reference to FIGS. 1 to 3.

  FIG. 1 is a block diagram showing the overall configuration of the electrophoretic display device according to this embodiment.

  In FIG. 1, an electrophoretic display device 1 according to this embodiment includes a display unit 3, a ROM 4, a RAM 5, a controller 10, and a CPU 100.

  The display unit 3 includes a display element having a memory property, and is a display device that maintains a display state even when writing is not performed. Note that the memory property refers to a property of maintaining a display state even when no voltage is applied when a predetermined display state is achieved by application of voltage, and is also referred to as bistability. A specific configuration of the display unit will be described in detail later.

  The ROM 4 is means for storing data used during operation of the electrophoretic display device. The ROM 4 stores, for example, a drive voltage waveform table for realizing a target display state in each pixel. The drive voltage waveform table will be described in detail later. The ROM 4 can be replaced with a rewritable storage means such as a RAM.

  The RAM 5 is a means for storing data used during the operation of the electrophoretic display device, like the ROM 4 described above. The RAM 5 stores, for example, data indicating the display state before the rewriting operation and data indicating the display state after the rewriting. The RAM 5 includes, for example, a VRAM that functions as a frame buffer, and stores frame image data based on the control of the CPU 100.

  The controller 10 controls the display operation of the display unit 3 using the data stored in the ROM 4 and RAM 5 described above. The controller 10 controls the display unit 3 by outputting an image signal indicating an image to be displayed on the display unit 3 and other various signals (for example, a clock signal).

  The CPU 100 is a processor that controls the operation of the electrophoretic display device 1, and reads and writes data by executing a program stored in advance. For example, when rewriting an image, the CPU 100 stores image data to be displayed on the display unit 3 in the VRAM.

  FIG. 2 is a block diagram showing a configuration around the display unit of the electrophoretic display device according to the present embodiment.

  In FIG. 2, the electrophoretic display device 1 according to the present embodiment is an active matrix drive type electrophoretic display device, and includes a display unit 3, a controller 10, a scanning line driving circuit 60, a data line driving circuit 70, and the like. And a common potential supply circuit 220.

  In the display unit 3, m rows × n columns of pixels 20 are arranged in a matrix (in a two-dimensional plane). The display unit 3 includes m scanning lines 40 (that is, scanning lines Y1, Y2,..., Ym) and n data lines 50 (that is, data lines X1, X2,..., Xn). It is provided so as to cross each other. Specifically, the m scanning lines 40 extend in the row direction (that is, the X direction), and the n data lines 50 extend in the column direction (that is, the Y direction). The pixels 20 are arranged corresponding to the intersections of the m scanning lines 40 and the n data lines 50.

  The controller 10 controls operations of the scanning line driving circuit 60, the data line driving circuit 70, and the common potential supply circuit 220. For example, the controller 10 supplies timing signals such as a clock signal and a start pulse to each circuit.

  The scanning line driving circuit 60 sequentially supplies a scanning signal in a pulsed manner to each of the scanning lines Y1, Y2,..., Ym during a predetermined frame period under the control of the controller 10.

  The data line driving circuit 70 supplies a data potential to the data lines X1, X2,..., Xn under the control of the controller 10. The data potential is any one of a reference potential GND (for example, 0 volt), a high potential VSH (for example, +15 volt), or a low potential -VSH (for example, -15 volt).

  The common potential supply circuit 220 supplies a common potential Vcom (in this embodiment, the same potential as the reference potential GND) to the common potential line 93. Note that the common potential Vcom is a potential different from the reference potential GND within a range in which no voltage is substantially generated between the counter electrode 22 supplied with the common potential Vcom and the pixel electrode 21 supplied with the reference potential GND. It may be. For example, the common potential Vcom may be a value different from the reference potential GND supplied to the pixel electrode 21 in consideration of fluctuations in the potential of the pixel electrode 21 due to feedthrough. In this specification, it is assumed that the common potential Vcom and the reference potential GND are the same.

  Here, the feed-through means that when the scanning signal is supplied to the scanning line 40 after the scanning signal is supplied to the scanning line 40 and the potential is supplied to the pixel electrode 21 via the data line 50 (for example, This refers to a phenomenon in which the potential of the pixel electrode 21 fluctuates due to parasitic capacitance with the scanning line 40 (for example, decreases with a decrease in the potential of the scanning line 40). The common potential Vcom may have a value slightly lower than the reference potential GND supplied to the pixel electrode 21 on the assumption that the potential of the pixel electrode 21 is lowered by feedthrough in advance. The potential Vcom and the reference potential GND are considered to be the same potential.

  Note that various signals are input to and output from the controller 10, the scanning line driving circuit 60, the data line driving circuit 70, and the common potential supply circuit 220, but descriptions of those that are not particularly related to the present embodiment are omitted. .

  FIG. 3 is an equivalent circuit diagram showing an electrical configuration of the pixel 20 according to the present embodiment.

  In FIG. 3, the pixel 20 includes a pixel switching transistor 24, a pixel electrode 21, a counter electrode 22, an electrophoretic element 23, and a storage capacitor 27.

  The pixel switching transistor 24 is composed of, for example, an N-type transistor. The pixel switching transistor 24 has a gate electrically connected to the scanning line 40, a source electrically connected to the data line 50, and a drain electrically connected to the pixel electrode 21 and the storage capacitor 27. It is connected to the. The pixel switching transistor 24 is configured to pulse the data potential supplied from the data line driving circuit 70 (see FIG. 2) via the data line 50 via the scanning line 40 from the scanning line driving circuit 60 (see FIG. 2). Are output to the pixel electrode 21 and the storage capacitor 27 at a timing corresponding to the scanning signal supplied to the pixel.

  A data potential is supplied to the pixel electrode 21 from the data line driving circuit 70 via the data line 50 and the pixel switching transistor 24. The pixel electrode 21 is disposed so as to face the counter electrode 22 via the electrophoretic element 23.

  The counter electrode 22 is electrically connected to a common potential line 93 to which a common potential Vcom is supplied.

  The electrophoretic element 23 is composed of a plurality of microcapsules each containing electrophoretic particles.

  The storage capacitor 27 is composed of a pair of electrodes arranged opposite to each other with a dielectric film therebetween, one electrode is electrically connected to the pixel electrode 21 and the pixel switching transistor 24, and the other electrode is a common potential line 93. Is electrically connected. The storage capacitor 27 can maintain the data potential for a certain period.

  Next, a specific configuration of the display unit of the electrophoretic display device according to the present embodiment will be described with reference to FIG.

  FIG. 4 is a partial cross-sectional view of the display unit 3 of the electrophoretic display device 1 according to the present embodiment.

  In FIG. 4, the display unit 3 is configured such that the electrophoretic element 23 is sandwiched between an element substrate 28 and a counter substrate 29. In the present embodiment, description will be made on the assumption that an image is displayed on the counter substrate 29 side.

  The element substrate 28 is a substrate made of, for example, glass or plastic. Although not shown here, the pixel switching transistor 24, the storage capacitor 27, the scanning line 40, the data line 50, the common potential line 93, and the like described above with reference to FIG. 2 are formed on the element substrate 28. A laminated structure is formed. A plurality of pixel electrodes 21 are provided in a matrix on the upper layer side of the stacked structure.

  The counter substrate 29 is a transparent substrate made of, for example, glass or plastic. On the surface of the counter substrate 29 facing the element substrate 28, the counter electrode 22 is formed in a solid shape so as to face the plurality of pixel electrodes 21. The counter electrode 22 is made of a transparent conductive material such as magnesium silver (MgAg), indium / tin oxide (ITO), indium / zinc oxide (IZO).

  The electrophoretic element 23 is composed of a plurality of microcapsules 80 each including electrophoretic particles, and is fixed between the element substrate 28 and the counter substrate 29 by a binder 30 and an adhesive layer 31 made of, for example, resin. . In the electrophoretic display device 1 according to this embodiment, in the manufacturing process, an electrophoretic sheet in which the electrophoretic element 23 is previously fixed to the counter substrate 29 side by the binder 30 is separately manufactured, such as the pixel electrode 21. It is constituted by being bonded by an adhesive layer 31 to the element substrate 28 side on which is formed.

  One or a plurality of microcapsules 80 are sandwiched between the pixel electrode 21 and the counter electrode 22, and are arranged in one pixel 20 (in other words, with respect to one pixel electrode 21).

  The microcapsule 80 is formed by enclosing a dispersion medium 81, a plurality of white particles 82, and a plurality of black particles 83 inside a coating 85. The microcapsule 80 is formed in a spherical shape having a particle size of about 50 μm, for example.

  The coating 85 functions as an outer shell of the microcapsule 80 and is formed of a translucent polymer resin such as acrylic resin such as polymethyl methacrylate and polyethyl methacrylate, urea resin, gum arabic, and gelatin. .

  The dispersion medium 81 is a medium for dispersing the white particles 82 and the black particles 83 in the microcapsules 80 (in other words, in the coating 85). Examples of the dispersion medium 81 include water, alcohol solvents such as methanol, ethanol, isopropanol, butanol, octanol, and methyl cellosolve, various esters such as ethyl acetate and butyl acetate, and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. , Aliphatic hydrocarbons such as pentane, hexane and octane, cycloaliphatic hydrocarbons such as cyclohexane and methylcyclohexane, benzene, toluene, xylene, hexylbenzene, hebutylbenzene, octylbenzene, nonylbenzene, decylbenzene, undecyl Aromatic hydrocarbons such as benzenes with long chain alkyl groups such as benzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene, etc., halo such as methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, etc. Emissions of hydrocarbons, carboxylate or other oils may be used singly or as a mixture. In addition, a surfactant may be added to the dispersion medium 81.

  The white particles 82 are particles (polymer or colloid) made of a white pigment such as titanium dioxide, zinc white (zinc oxide), and antimony trioxide, and are negatively charged, for example.

  The black particles 83 are particles (polymer or colloid) made of a black pigment such as aniline black or carbon black, and are positively charged, for example.

  For this reason, the white particles 82 and the black particles 83 can move in the dispersion medium 81 by the electric field generated by the potential difference between the pixel electrode 21 and the counter electrode 22.

  These pigments include electrolytes, surfactants, metal soaps, resins, rubbers, oils, varnishes, charge control agents composed of particles such as compounds, titanium-based coupling agents, aluminum-based coupling agents, silanes as necessary. A dispersant such as a system coupling agent, a lubricant, a stabilizer, and the like can be added.

  In FIG. 4, when a voltage is applied between the pixel electrode 21 and the counter electrode 22 so that the potential of the counter electrode 22 is relatively high, the positively charged black particles 83 are caused by Coulomb force. While attracted to the pixel electrode 21 side in the microcapsule 80, the negatively charged white particles 82 are attracted to the counter electrode 22 side in the microcapsule 80 by the Coulomb force. As a result, the white particles 82 gather on the display surface side (that is, the counter electrode 22 side) in the microcapsule 80, and the color of the white particles 82 (that is, white) is displayed on the display surface of the display unit 3. Will be displayed. Conversely, when a voltage is applied between the pixel electrode 21 and the counter electrode 22 so that the potential of the pixel electrode 21 becomes relatively high, the negatively charged white particles 82 are generated by the Coulomb force. While attracted to the electrode 21 side, the positively charged black particles 83 are attracted to the counter electrode 22 side by Coulomb force. As a result, the black particles 83 are collected on the display surface side of the microcapsule 80, and the color of the black particles 83 (that is, black) is displayed on the display surface of the display unit 3.

  In addition, red, green, blue, etc. can be displayed by replacing the pigment used for the white particle 82 and the black particle 83 with pigments, such as red, green, and blue, for example.

  Next, the operation at the time of image rewriting in the electrophoretic display device according to this embodiment will be described with reference to two embodiments.

<First Embodiment>
First, the operation at the time of image rewriting in the electrophoretic display device according to the first embodiment will be described with reference to FIG. In the following, for convenience of explanation, the operation at the time of rewriting will be described focusing on only the first pixel and the second pixel which are two adjacent pixels. Each process shown below is typically performed by the controller 10, but may be performed by other than the controller 10.

  FIG. 5 is a flowchart showing a control method of the electrophoretic display device according to this embodiment.

  In FIG. 5, when the electrophoretic display device according to the present embodiment operates, when an instruction is given to rewrite an image first (step S01: YES), voltage pulses supplied to the first pixel and the second pixel. Are compared (step S02). The waveform of the voltage pulse supplied to each pixel is set based on, for example, a gradation before rewriting and a gradation after rewriting (hereinafter referred to as “target gradation” as appropriate). Note that the gradation here is an example of the “optical state” of the present invention, and can be rephrased as, for example, brightness or reflectance. The target gradation is an example of the “first optical state” and the “second optical state” in the present invention.

  Subsequently, as a result of comparing the voltage pulses supplied to the first pixel and the second pixel, it is determined whether or not a reverse polarity period occurs (step S03). Here, the reverse polarity period is a period in which voltages having different polarities are applied to the first pixel and the second pixel. When the reverse polarity period occurs, the influence of the lateral electric field between the first pixel and the second pixel increases, and the display image may be disturbed. Therefore, it is preferable that the reverse polarity does not occur or is as short as possible even if it occurs.

  Hereinafter, the occurrence of the reverse polarity period will be described in detail with reference to FIG. In the following description, the electrophoretic display device 1 according to this embodiment will be described by taking as an example a case in which eight levels of gradation can be displayed. Here, the gradation corresponding to black is level 0, the gradation corresponding to white is level 7, and the intermediate gradation between black and white is indicated by level 1 to level 6, respectively.

  FIG. 6 is a conceptual diagram illustrating the occurrence of a reverse polarity period in an adjacent pixel according to the first embodiment.

  In FIG. 6, a case is considered where the first pixel is rewritten from the intermediate gray level 3 to the intermediate gray level 4, and the second pixel is rewritten from the intermediate gray level 4 to the intermediate gray level 3. .

  In this case, 14 frames of the drive voltage −VSH corresponding to white is applied to the first pixel in phase A. Phase A is set as a period during which the gray level that has been displayed so far is applied for a long time until it becomes white. According to the phase A, it is possible to align the positions of the white particles 82 and the black particles 83 having variations in each pixel by displaying white before realizing the intermediate gradation that is the target gradation. . Therefore, when displaying the intermediate gradation, it is possible to prevent the displayed gradation from being varied due to the variation in the particle position in each pixel. The phase A here is an example of the “first control step” in the present invention.

  Subsequently, in the phase B, the driving voltage VSH corresponding to black (that is, a potential having a polarity opposite to that of the phase A) is applied to the first pixel for one frame. Phase B is set as a period for changing the white gradation in phase A to the target gradation. Phase B here is an example of the “second control step” in the present invention.

  On the other hand, the driving voltage −VSH corresponding to white in phase A is applied to the second pixel for 13 frames. Note that the phase A period (that is, 13 frames) in the second pixel is shorter than the phase A (that is, 14 frames) in the first pixel. This is because the gradation before rewriting of the second pixel (ie, level 4) is closer to white than the gradation before rewriting of the first pixel (ie, level 3). ing. Phase A here is an example of the “third control step” in the present invention.

  Subsequently, in the phase B, the driving voltage VSH corresponding to black is applied to the second pixel for two frames. Phase B is set as a period for changing the white gradation in phase A to the target gradation. Note that the phase B period (that is, two frames) in the second pixel is longer than the phase B (that is, one frame) in the first pixel. This is because the target gradation (ie, level 3) of the second pixel is closer to black than the target gradation (ie, level 4) of the first pixel. Phase B here is an example of the “fourth control step” in the present invention.

  As described above, when the phase A and the phase B in which voltages having different polarities are supplied to each of the first pixel and the second pixel, the phase A is generated between the first pixel and the second pixel. Therefore, there is a difference in the end timing of phase A (in other words, the start timing of phase B). As a result, the period in which phase A is performed in the first pixel overlaps the period in which phase B is performed in the second pixel, and voltages having different polarities are applied to the first pixel and the second pixel. A reverse polarity period occurs.

  Returning to FIG. 5, if it is determined that a reverse polarity period occurs (step S03: YES), a phase Z for reducing the reverse polarity period is set for the second pixel (step S04). Hereinafter, the phase Z will be described in detail with reference to FIG.

  FIG. 7 is a conceptual diagram showing a voltage application method after the phase Z is set.

  In FIG. 7, phase Z is a period during which the same potential (that is, GND) as that of the counter electrode 22 is supplied to the pixel electrode 21 of the second pixel, and is set as a period between phase A and phase B. Phase Z is an example of the “fifth control step” in the present invention.

  The phase Z here is set as a period having a length of one frame. The length of the phase Z is set according to the difference between the phase A period (that is, 14 frames) in the first pixel and the phase A period (that is, 13 frames) in the second pixel. By setting phase Z in this way, the start timing of phase B in the second pixel is delayed by one frame, and as a result, the start timing of phase B in the first pixel and the start timing of phase B in the second pixel are Aligned.

  By aligning the start timing of phase B in the first pixel and the second pixel, the reverse polarity period as shown in FIG. 6 can be eliminated. Accordingly, it is possible to suppress the disturbance of the display image caused by the lateral electric field. Here, the case where the reverse polarity period is completely eliminated has been described as an example. However, if the reverse polarity period can be somewhat shortened, the above-described effects can be obtained accordingly.

  Note that by setting the phase Z, a period in which −VSH is supplied to the first pixel and GND is supplied to the second pixel occurs. That is, a period in which a voltage is applied only to one of the first pixel and the second pixel occurs. Such a period may increase the influence of the lateral electric field as compared with the case where the polarities of the driving voltages applied to the first pixel and the second pixel are the same. However, compared with the reverse polarity period described above, the influence is definitely small. Therefore, by setting the phase Z, it is possible to reliably suppress display disturbance caused by the lateral electric field.

  In the above-described embodiment, the case where the phase Z is set between the phase A and the phase B is described as an example. However, the phase Z may be set before the phase A. In this case, since the start timing of phase A in the second pixel is delayed by one frame, the end timing of phase A is aligned in the first pixel and the second pixel, and the start timing of phase B is also aligned. Therefore, even when the phase Z is set before the phase A, the same effect as that of the above-described embodiment can be obtained.

Second Embodiment
Next, an operation at the time of image rewriting in the electro-optical device according to the second embodiment will be described. Note that the second embodiment differs from the first embodiment described above only in some operations, and the other operations are substantially the same. For this reason, below, a different part from 1st Embodiment is demonstrated in detail, and description is abbreviate | omitted suitably about another overlapping part.

  According to the study by the present inventor, there is a case where the target gradation cannot be realized only by the phase B due to the characteristics of the electrophoretic element 23 when the gradation is changed from white to an intermediate gradation. It is known to get. Hereinafter, the characteristics of the electrophoretic element 23 will be described with reference to FIGS. 8 and 9.

  FIG. 8 is a graph showing changes in gradation when rewriting from white to black.

  In FIG. 8, when the image is rewritten from white to black, the change in gradation with respect to the period during which the voltage is applied is large immediately after the start of rewriting, but tends to decrease as the opposite gradation is approached. That is, the gradation changes greatly in the black direction at the time when the gradation is close to white, but the gradation becomes difficult to change as it approaches black.

  FIG. 9 is a graph showing a change in gradation when rewriting from black to white.

  In FIG. 9, when the image is rewritten from black to white, the change in gradation with respect to the period during which the voltage is applied is large immediately after the start of rewriting, but tends to decrease as the opposite gradation is approached. That is, the gradation changes greatly in the white direction at the time when the gradation is close to black, but the gradation becomes difficult to change as it approaches white.

  When the electrophoretic element 23 has the above-described characteristics, for example, the intermediate gray levels of the level 3 and the level 4 shown in FIGS. 6 and 7 can be realized only by the phase A and the phase B. However, even when the drive voltage VSH is applied only for one frame, which is the minimum unit in the phase B, the gradation level 7 becomes an intermediate gradation level 4. For this reason, for example, the intermediate gray levels of level 5 and level 6 are difficult to be realized only by phase A and phase B.

  On the other hand, in the present embodiment, when the target gradation cannot be realized only by the phase A and the phase B, the phase B for realizing the gradation closer to black than the target gradation is set. Phase C for setting the key to the target gradation is set.

  Phase C is a period that is set to bring the gray level that is closer to black than the target gray level by applying the voltage in phase B closer to the target gray level. In phase C, a drive voltage VSH corresponding to white (that is, a voltage having the same polarity as phase A) is applied to the pixel to be rewritten.

  In the following, the target gradation realization method using phase C and the reverse polarity period generated when phase C is used will be described with reference to FIG.

  FIG. 10 is a conceptual diagram illustrating the occurrence of a reverse polarity period in an adjacent pixel according to the second embodiment.

  In FIG. 10, a case is considered where the first pixel is rewritten from the intermediate gray level 3 to the intermediate gray level 5 and the second pixel is rewritten from the intermediate gray level 4 to the intermediate gray level 6. .

  In this case, 14 frames of the drive voltage −VSH corresponding to white is applied to the first pixel in phase A. As a result, the gradation of the first pixel becomes level 7.

  Subsequently, in the phase B, the driving voltage VSH corresponding to black (that is, a potential having a polarity opposite to that of the phase A) is applied to the first pixel for two frames. Thereby, the gradation of the first pixel becomes level 3.

  Phase C for the first pixel is set as a period in which the gradation that has reached level 3 by phase B (that is, the gradation closer to black than the target gradation) is level 5 that is the target gradation. In phase C, since the drive voltage −VSH corresponding to white is applied, the gradation is brought close to white. At this time, as shown in FIG. 9, the change rate of the gradation is smaller than that of the phase B having a relatively high change rate. That is, in phase C, the gradation changes more slowly than in phase B. Therefore, if two frames of the drive voltage −VSH are applied in phase C, the intermediate gray level that was level 3 can be changed to level 5 that is the target gray level.

  On the other hand, the driving voltage −VSH corresponding to white in phase A is applied to the second pixel for 13 frames. As a result, the gradation of the first pixel becomes level 7.

  Subsequently, in the phase B, the driving voltage VSH corresponding to black is applied to the second pixel for one frame. Phase B is set as a period for changing the white gradation in phase A to the target gradation. As a result, the gradation of the first pixel becomes level 4.

  Phase C for the second pixel is set as a period in which the gradation that has reached level 4 by phase B (that is, the gradation closer to black than the target gradation) is level 6 that is the target gradation. In phase C, since the drive voltage −VSH corresponding to white is applied, the gradation is brought close to white. At this time, as in the case of the first pixel described above, the gradation in Phase C changes more slowly than in Phase B. Therefore, if 4 frames of drive voltage -VSH are applied in phase C, the intermediate gray level that was level 4 can be changed to level 6 that is the target gray level.

  As described above, when Phase A, Phase B, and Phase C for supplying voltages having different polarities to each of the first pixel and the second pixel are performed, the first pixel, the second pixel, Therefore, there is a difference between the end timing of phase A (in other words, the start timing of phase B) and the end timing of phase B (in other words, the start timing of phase C). Accordingly, the period in which the phase A in the first pixel is performed overlaps the period in which the phase B in the second pixel is performed, or the period in which the phase B is performed in the first pixel and the second pixel By overlapping with the period in which phase C is performed, a reverse polarity period in which voltages having different polarities are applied to the first pixel and the second pixel occurs.

  In the present embodiment, two phases of the phase Z0 and the phase Z1 are set for the second pixel as the period in order to reduce the above-described reverse polarity period. Hereinafter, the phase Z0 and the phase Z1 will be described in detail with reference to FIG.

  FIG. 11 is a conceptual diagram showing a voltage application method after setting the phases Z0 and Z1.

  In FIG. 11, a phase Z0 is a period in which the same potential (that is, GND) as that of the counter electrode 22 is supplied to the pixel electrode 21 of the second pixel, and is set as a period before the phase A. The phase Z0 is an example of the “fifth control step” in the present invention. In this case, the phase A in the first pixel is an example of the “first control step” in the present invention, and the phase B in the first pixel. Is an example of the “second control step” in the present invention, phase A in the second pixel is an example of the “third control step” in the present invention, and phase B in the second pixel is the “second control step” in the present invention. It is an example of “4 control process”.

  The phase Z0 here is set as a period having a length of one frame. The length of the phase Z0 is set according to the difference between the phase A period (that is, 14 frames) in the first pixel and the phase A period (that is, 13 frames) in the second pixel. By setting phase Z0 in this way, the start timing of phase B in the second pixel is delayed by one frame, and as a result, the start timing of phase B in the first pixel and the start timing of phase B in the second pixel are Aligned.

  On the other hand, the phase Z1 is a period in which the same potential (that is, GND) as that of the counter electrode 22 is supplied to the pixel electrode 21 of the second pixel, and is set as a period between the phase B and the phase C. The phase Z1 is an example of the “fifth control step” of the present invention, similarly to the phase Z0. In this case, the phase B in the first pixel is an example of the “first control step” of the present invention. Phase C in this pixel is an example of the “second control step” of the present invention, Phase B in the second pixel is an example of the “third control step” in the present invention, and Phase C in the second pixel is It is an example of "the 4th control process" of the present invention.

  The phase Z1 here is set as a period having a length of one frame. The length of the phase Z1 is set according to the difference between the phase B period (that is, two frames) in the first pixel and the phase B period (that is, one frame) in the second pixel. By setting the phase Z1 in this way, the start timing of the phase C in the second pixel is delayed by one frame (more precisely, the delay by the phase Z0 and two frames is delayed). As a result, the phase in the first pixel The start timing of C and the start timing of phase C in the second pixel are aligned.

  As described above, the reverse polarity period as shown in FIG. 10 can be eliminated by aligning the start timings of the phase B and the phase C in the first pixel and the second pixel. Accordingly, it is possible to suppress the disturbance of the display image caused by the lateral electric field.

  Here, the case where two phases of the phase Z0 and the phase Z1 are set for the second pixel as a period for reducing the reverse polarity period is described as an example. 3 includes more phases, three or more phases may be set as a period for reducing the reverse polarity period.

  As described above, according to the electrophoretic display device according to the present embodiment, it is possible to display a desired intermediate gradation suitably while preventing an increase in the influence of the lateral electric field. Therefore, a high quality image can be displayed.

  In the above embodiment, the white particles 82 are negatively charged and the black particles 83 are positively charged. However, the white particles 82 are positively charged and the black particles 83 are negatively charged. May be. Further, the electrophoretic element 23 is not limited to the configuration having the microcapsules 80, and may be a configuration in which the electrophoretic dispersion medium and the electrophoretic particles are included in a space partitioned by the partition walls. Further, the electro-optical device having the electrophoretic element 23 has been described as an example, but the present invention is not limited to this. The electro-optical device may be, for example, an electro-optical device using an electronic powder fluid.

<Electronic equipment>
Next, electronic devices to which the above-described electrophoretic display device is applied will be described with reference to FIGS. Below, the case where the electrophoretic display device described above is applied to electronic paper and electronic notebook is taken as an example.

  FIG. 12 is a perspective view illustrating a configuration of the electronic paper 1400.

  As illustrated in FIG. 12, the electronic paper 1400 includes the electrophoretic display device according to the above-described embodiment as a display unit 1401. The electronic paper 1400 has flexibility, and includes a main body 1402 formed of a rewritable sheet having the same texture and flexibility as conventional paper.

  FIG. 13 is a perspective view showing the configuration of the electronic notebook 1500.

  As shown in FIG. 13, an electronic notebook 1500 is obtained by bundling a plurality of electronic papers 1400 shown in FIG. The cover 1501 includes display data input means (not shown) 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 is bundled.

  Since the electronic paper 1400 and the electronic notebook 1500 described above include the electrophoretic display device according to the above-described embodiment, high-quality image display can be performed.

  In addition to these, the electrophoretic display device according to the present embodiment described above can be applied to a display unit of an electronic device such as a wristwatch, a mobile phone, or a portable audio device.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and an electro-optical device with such a change. The control method, electro-optical device control device, electro-optical device, and electronic apparatus are also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 3 ... Display part, 4 ... ROM, 5 ... RAM, 10 ... Controller, 20 ... Pixel, 21 ... Pixel electrode, 22 ... Counter electrode, 24 ... Pixel switching transistor, 28 ... Element substrate, 29 ... Counter substrate, 40 ... Scan line 50... Data line 60. Scan line drive circuit 70 70 Data line drive circuit 82. White particle 83 83 Black particle 100 CPU 220 Common potential supply circuit

Claims (10)

A plurality of pixels provided corresponding to the intersection of a plurality of scanning lines and a plurality of data lines intersecting each other, each having a pixel electrode facing each other and an electro-optic material between the counter electrodes, A display unit capable of taking a plurality of intermediate optical states between the first limit optical state and the second limit optical state, and the display unit according to image data A control method for controlling an electro-optical device including a driving unit that supplies a voltage pulse corresponding to the image data to each of the pixel electrodes of each of the plurality of pixels in a plurality of frame periods in order to display a captured image. There,
A control step when the first pixel among the plurality of pixels is shifted to the first intermediate optical state,
A first control step of supplying a first voltage pulse to the pixel electrode of the first pixel;
After the first control step, a second control step of supplying a second voltage pulse having a polarity opposite to the first voltage pulse to the pixel electrode of the first pixel;
A control step for shifting a second pixel adjacent to the first pixel to the second intermediate optical state;
A third control step of supplying a third voltage pulse having the same polarity as the first voltage pulse to the pixel electrode of the second pixel;
A fourth control step of supplying, after the third control step, a fourth voltage pulse having the same polarity as the second voltage pulse to the pixel electrode of the second pixel;
Including
The first control step and the third control step are performed in duplicate in at least one frame period,
The first control step and the third control step are started simultaneously, and the first control step and the second control step, and the third control step and the fourth control step are continuous. when it is assumed to be performed Te, period duration and the fourth control step the first control process is performed is performed, or the period of time and the third control step of the second control process is performed is performed from one another When overlapping reverse polarity periods occur,
In the second pixel control step , the fifth pixel having the same potential as the counter electrode with respect to the pixel electrode of the second pixel is set so that the reverse polarity period is shorter than the period occurring in the assumption. Control step for supplying a voltage pulse of at least one frame period
The method of controlling an electro-optical device further comprising:   The method of controlling an electro-optical device according to claim 1, wherein the fifth control step is performed before the third control step.   In the fifth control step, a frame period for supplying the fifth voltage pulse is set so that a timing at which the first control step ends and a timing at which the third control step ends are aligned with each other. The method of controlling an electro-optical device according to claim 2.   The electro-optical device control method according to claim 1, wherein the fifth control step is performed between the third control step and the fourth control step.   In the fifth control step, a frame period for supplying the fifth voltage pulse is set so that a timing at which the second control step starts and a timing at which the fourth control step starts are aligned with each other. The method of controlling an electro-optical device according to claim 4. The first control step is a step of supplying the first voltage pulse to the pixel electrode of the first pixel until the first extreme optical state is reached.
The second control step is a step of supplying the second voltage pulse to the pixel electrode of the first pixel so as to approach the first intermediate optical state,
The third control step is a step of supplying the third voltage pulse to the pixel electrode of the second pixel until the first limit optical state is reached.
The fourth control step is a step of supplying the fourth voltage pulse to the pixel electrode of the second pixel so as to approach the second intermediate optical state. Item 6. The control method for an electro-optical device according to any one of Items 1 to 5. In the first control step, the first electrode until the intermediate optical state farther from the optical state before the first control step than the first intermediate optical state with respect to the pixel electrode of the first pixel. A step of supplying a voltage pulse of
The second control step is a step of supplying the second voltage pulse to the pixel electrode of the first pixel until reaching the first intermediate optical state.
In the third control step, the third electrode step is performed until the pixel electrode of the second pixel reaches an intermediate optical state farther from the optical state before the third control step than the second intermediate optical state. A step of supplying a voltage pulse of
The fourth control step is a step of supplying the fourth voltage pulse to the pixel electrode of the second pixel until reaching the second intermediate optical state. The method of controlling an electro-optical device according to any one of 1 to 5. A plurality of pixels provided corresponding to the intersection of a plurality of scanning lines and a plurality of data lines intersecting each other, each having a pixel electrode facing each other and an electro-optic material between the counter electrodes, A display unit capable of taking a plurality of intermediate optical states between the first limit optical state and the second limit optical state, and the display unit according to image data A control unit that controls an electro-optical device including a drive unit that supplies a voltage pulse corresponding to the image data to each pixel electrode of each of the plurality of pixels in a plurality of frame periods in order to display a captured image. There,
When shifting the first pixel of the plurality of pixels to the first intermediate optical state,
First control means for supplying a first voltage pulse to the pixel electrode of the first pixel;
After the first voltage pulse is supplied by the first control means, a second voltage pulse having a polarity opposite to the first voltage pulse is supplied to the pixel electrode of the first pixel. Two control means;
When shifting the second pixel adjacent to the first pixel to the second intermediate optical state,
Third control means for supplying a third voltage pulse having the same polarity as the first voltage pulse to the pixel electrode of the second pixel;
After the third voltage pulse is supplied by the third control means, a fourth voltage pulse having the same polarity as the second voltage pulse is supplied to the pixel electrode of the second pixel. 4 control means;
The period during which the first voltage pulse is supplied by the first control means and the period during which the fourth voltage pulse is supplied by the fourth control means, or the second voltage pulse is supplied by the second control means. The counter electrode with respect to the pixel electrode of the second pixel is shortened so that a reverse polarity period in which the supplied period and the period in which the third voltage pulse is supplied by the third control unit overlap each other is shortened. And a fifth control means for supplying a fifth voltage pulse having the same potential as at least one frame period.   An electro-optical device comprising the control device for an electro-optical device according to claim 8.   An electronic apparatus comprising the electro-optical device according to claim 9.