JP2012237960A - Control method of electro-optic device, control device of electro-optic device, electro-optic device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of a contour afterimage in a displayed image.SOLUTION: A control method of an electro-optic device comprises: a first supply step of supplying a voltage to a pixel electrode (21) of a first pixel where the grayscale to be displayed is changed upon rewiring an image, the potential corresponding to the grayscale after changed; and a second supply step of supplying the same potential as the potential of a counter electrode (22) to a pixel electrode of a second pixel where the grayscale to be displayed is not changed; an extraction step (S101) of extracting a contour image (C) from the difference (B) between an image (A1) before image rewriting and an image (A2) after image rewriting; a determining step (S102) of determining whether or not the first supply step is carried out in each pixel unit in contour display pixels that display the contour image; and a contour erasing step (S103) of supplying a potential to erase the contour image to the pixel electrode of a pixel determined as not being subjected to the first supply step in the couture display pixels.

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 (see, for example, Patent Documents 1 and 2). 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, when the image displayed on the display unit is rewritten, if the image changes only partially, a voltage is applied between the pixel electrode and the counter electrode of only the pixel corresponding to the changed portion. In some cases, a driving method in which an image is partially rewritten by applying (hereinafter referred to as “partial rewriting driving” as appropriate) may be employed. In the electrophoretic display device adopting such partial rewriting drive, for example, a boundary portion between a black image portion displayed in black and a white image portion displayed in white in an image displayed on the display portion is blurred. In other words, it is known that the black image portion may be displayed as if the outline portion of the black image portion is expanded (or swelled) toward the white image portion. (For example, refer to Patent Document 2).

  When such blurring of the boundary portion occurs, when the image displayed on the display portion is rewritten to an all-white image by applying a voltage only to the pixels corresponding to the black image portion, the blurring of the boundary portion becomes an afterimage. In other words, there is a possibility that an afterimage along the contour of the black image portion that has been displayed may occur. Hereinafter, a phenomenon in which such an afterimage along the contour portion occurs, or an afterimage itself along such a contour portion is appropriately referred to as a “contour afterimage”. For example, in Patent Document 2, when an image displayed on a display unit is rewritten by partial rewrite driving, a portion that remains as a contour afterimage (for example, a white color that is arranged adjacent to a pixel corresponding to a contour portion of a black image portion is displayed. A technique for erasing a contour afterimage by applying a voltage so as to rewrite a pixel to be displayed) is also disclosed.

Japanese Patent No. 3750565 JP 2010-113281 A

  However, according to the technique disclosed in Patent Document 2 described above, processing for erasing the contour afterimage occurs every time the image is rewritten, so that the time required for the image rewriting becomes long. As a result, for example, display switching between a plurality of pages cannot be performed smoothly, and usability may be greatly reduced. That is, the technique disclosed in Patent Document 2 has a technical problem that even if the afterimage after the image rewriting can be erased, a new inconvenience occurs.

  The present invention has been made in view of the above-described problems, for example, and can appropriately suppress the occurrence of a contour afterimage in an image displayed on a display unit, and can control an electro-optical device capable of displaying a high-quality image, It is an object to provide a control device for an electro-optical 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 display unit having a plurality of pixels each including an electro-optic material, and a data potential corresponding to the image data on each pixel electrode of the plurality of pixels 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 drive unit that supplies a plurality of potentials during a predetermined frame period, when rewriting an image displayed on the display unit. A first supply step of supplying a potential corresponding to the changed gradation to the pixel electrode of the first pixel in which the gradation to be changed is changed; and the gradation to be displayed is not changed in the image rewriting. 2 A second supply step for supplying the same potential as the potential of the counter electrode to the pixel electrode of the pixel; an extraction step for extracting a contour image from a difference between the image before the image rewriting and the image after the image rewriting; A determination step for determining whether or not the first supply step is performed on a pixel-by-pixel basis for a contour display pixel that displays the contour image, and the first supply step is not performed among the contour display pixels. A contour erasing step of supplying a potential for erasing the contour image to the pixel electrode of the pixel determined to be.

  The electro-optical device controlled by the control method of the electro-optical device according to the present invention is, for example, an active matrix drive type electrophoretic display device or the like, and corresponds to the intersection of a plurality of scanning lines and a plurality of data lines, for example. A display unit having a plurality of pixels arranged in a matrix and a drive unit for supplying a data potential corresponding to image data to the pixel electrode of each pixel are provided.

  In the electro-optical device, a data potential corresponding to image data is supplied to a pixel electrode in each of a plurality of pixels in a plurality of times by a driving unit, whereby an image corresponding to the image data is displayed on the display unit. The potential supply by the drive unit is performed, for example, in a predetermined frame period. Specifically, during a predetermined frame period, a plurality of scanning lines are selected once in a predetermined order, and a data potential is applied to the pixel electrode in the 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, the potential supply for supplying the data potential to the pixel electrode in each of the plurality of pixels is performed once by the drive unit, whereby an image corresponding to the image data is displayed on the display unit. Is done.

  According to the control method of the electro-optical device according to the present invention, when the image is rewritten to rewrite an image displayed on the display unit (for example, a two-gradation image composed of two gradations of white and black), the above-described multiple times are performed. As the potential supply, the first supply process and the second supply process are performed. The first supply process and the second supply process are processes performed in parallel with each other.

  In the first supply process, the potential corresponding to the changed gradation (for example, the pixel electrode of the first pixel in which the gradation to be displayed changes (for example, changes from black to white or from white to black)). , A high potential higher than the potential of the counter electrode, or a low potential lower than the potential of the counter electrode). By such potential supply being performed a plurality of times, the gradation of the first pixel changes so as to approach the gradation to be displayed stepwise.

  In the second supply step, the same potential (for example, 0 volt) as the potential of the counter electrode is supplied to the pixel electrode of the second pixel in which the gradation to be displayed does not change (for example, is maintained as black or white). Is done. For this reason, unlike the above-described first pixel, the second pixel maintains the displayed gradation. Note that the “potential that is the same as the potential of the counter electrode” here does not mean only a strictly equal potential but includes a slightly different potential. For example, even when the counter electrode potential is a value different from the potential supplied to the pixel electrode of the second pixel in consideration of the fluctuation of the pixel electrode potential due to feedthrough, the pixel of the second pixel It is considered that the potential supplied to the electrode and the potential of the counter electrode are the same.

  In the present invention, the contour image is further extracted from the difference between the image before image rewriting and the image after image rewriting in the extraction step. The extraction step may be performed, for example, every time the image is rewritten, or may be performed every time the image is rewritten a predetermined number of times. The “contour image” is an image corresponding to a contour afterimage generated by partial image rewriting as in the first supply process and the second supply process described above. Hereinafter, the principle of generating the afterimage will be described with a specific example.

  For example, let us consider a case where only one pixel is rewritten to black from a state where two adjacent pixels both display white, and then is rewritten to a state where both pixels are displayed again. In this case, when one of the pixels is rewritten to black, blurring due to the above-described leakage or the like occurs in the pixels that should hold the adjacent white (that is, the vicinity of the boundary between the pixels that should hold the white is a part) Will turn gray). This blur is relatively difficult to visually recognize while one pixel displays black. However, even after one of the pixels displaying black is rewritten to white again, the bleeding that has occurred in the pixels that continue to retain the white color remains, and as a result, the pixels that have been rewritten from black to white are surrounded. Such an afterimage is generated.

  When the contour image corresponding to the contour afterimage is extracted, in the determination step, a contour display pixel that displays the contour image (that is, a pixel in which a gradation that should not be displayed is displayed as a contour afterimage) in pixel units, It is determined whether or not the first supply process is being performed. That is, it is determined on a pixel-by-pixel basis whether or not potential supply for changing the display gradation is performed for each of the contour display pixels. Such a determination can be realized, for example, by providing a memory or the like that can store a voltage supply state in units of pixels.

  Here, in the present invention, in particular, in the contour erasing step, a potential for erasing the contour image is supplied to the pixel electrode of the pixel that is determined not to be subjected to the first supply step among the contour display pixels. Specifically, for example, when a gray outline afterimage is displayed in a pixel that should display white, a potential for displaying white is supplied. Alternatively, when a gray outline afterimage is displayed in a pixel that should display black, a potential for displaying black is supplied. As a result, the gradation of the contour display pixel changes to the gradation that should be displayed, and the afterimage can be erased or reduced. The potential supply in the contour erasing process is typically performed only once, but may be performed a plurality of times as in the first supply process and the second supply process.

  As described above, according to the control method of the electro-optical device according to the present invention, since the image rewriting state of the contour display pixel can be determined on a pixel-by-pixel basis through the determination step, image rewriting is not performed (that is, gradation) The contour image can be sequentially erased from the pixels to which no potential for changing the voltage is supplied. As a result, when viewed on the entire display unit, the image rewriting operation and the contour erasing operation are driven as if progressing simultaneously in each pixel, and it is possible to realize a state in which the contour afterimage is extremely difficult to visually recognize. As a result, a high quality image can be displayed.

  In one aspect of the control method of the electro-optical device according to the present invention, in the contour erasing step, the pixel electrodes of the pixels determined to have not been subjected to the first supply step among the contour display pixels are adjacent to each other. In the last frame period of the first supply process performed for the matching pixels, a potential for erasing the contour image is supplied.

  According to this aspect, in accordance with the last frame period of the first supply process performed on the pixels adjacent to the contour display pixels (that is, the last frame period among a plurality of frame periods required for image rewriting). The afterimage of the contour display pixel is erased. If the contour afterimage is erased at such timing, the contour afterimage is erased at the same time as the rewriting of the image is completed.

  Note that the potential supply in the contour erasing process may be performed only during the last frame period of the first supply process performed on the pixels adjacent to the contour display pixel, or may be performed including other frame periods. May be.

  In another aspect of the control method of the electro-optical device according to the invention, in the contour erasing step, the pixel electrode of the pixel that is determined to be performing the first supply step among the contour display pixels, In the frame period after the first supply process is completed, a potential for erasing the contour image is supplied.

  According to this aspect, the potential for erasing the contour image is applied to the pixel electrode of the pixel determined to have undergone the first supply process in the determination process in the frame period after the completion of the first supply process. Supplied. For this reason, even if the contour display pixel has been rewritten at the stage where it is determined that the contour afterimage is displayed, the contour afterimage can be surely erased as soon as the image rewriting is completed.

  In another aspect of the method for controlling an electro-optical device according to the present invention, the contour erasing step is performed once for a plurality of times of the image rewriting.

  According to this aspect, the contour erasing step is not performed every time the image is rewritten, but is performed every time the image is rewritten a plurality of times. As a result, the afterimages generated by a plurality of image rewrites are erased collectively. It should be noted that how many times image rewriting is performed is set in advance based on the effect of removing the afterimage. However, this number of times may be variable.

  When erasing the contour afterimages together, the contour afterimage is extracted as a contour image generated by a plurality of image rewritings in the extraction step. For example, if a logical sum of contour images generated in each of a plurality of image rewrites is taken, a plurality of contour images can be easily extracted.

  If the contour afterimages are erased collectively, the number of times of performing the contour erasure process can be reduced, so that higher-speed image display can be realized. Therefore, it is possible to achieve both high-speed image display and display quality improvement.

  In another aspect of the control method of the electro-optical device according to the invention, the period for supplying the potential for erasing the contour image in the contour erasing step corresponds to the gradation after the change in the first supplying step. It is shorter than the period for supplying the potential.

  According to this aspect, since the period for supplying the potential for erasing the contour image in the contour erasing step can be made relatively short, the processing can be simplified. Further, the DC balance ratio (that is, the time during which a voltage corresponding to one gradation is applied between the pixel electrode and the counter electrode, and the time during which a voltage according to another gradation is applied between the pixel electrode and the counter electrode. Can be prevented or prevented from collapsing.

  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 display unit having a plurality of pixels each including an electro-optic material, and a data potential corresponding to the image data on each pixel electrode of the plurality of pixels 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 a plurality of potentials during a predetermined frame period, and displays the image displayed on the display unit when rewriting the image. First supply means for supplying a potential corresponding to the changed gradation to the pixel electrode of the first pixel whose gradation to be changed is changed, and the gradation to be displayed is not changed when the image is rewritten. 2 Second supply means for supplying the same potential as that of the counter electrode to the pixel electrode of the pixel; and extraction means for extracting a contour image from a difference between the image before image rewriting and the image after image rewriting; A determination unit that determines whether or not the potential supply by the first supply unit is performed on a pixel-by-pixel basis for a contour display pixel that displays the contour image, and the first supply unit among the contour display pixels Contour erasing means for supplying a potential for erasing the contour image to the pixel electrode of the pixel that is determined not to be supplied with potential.

  According to the control device for the electro-optical device according to the present invention, the afterimage after the image rewriting in the electro-optical device can be reduced in the same manner as the control method for the electro-optical device according to the present invention described above. 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 one aspect of the control apparatus for the electro-optical device according to the present invention, the number storage means for storing the number of times the potential supply should be performed by the first supply means for each of the plurality of pixels, and the potential supply is performed. Decrementing means for decrementing the number of times to supply the potential stored in the number of times storage means.

  According to this aspect, the potential supply by the first supply means (that is, the potential for changing the display gradation) to each of the plurality of pixels by the number storage means configured by, for example, a RAM (Random Access Memory) or the like. The number of times to be supplied) is stored. Specifically, for example, when pixels of i rows and j columns are arranged on the display unit, the number of times of potential supply to each pixel is set in i × j storage areas of the number storage means. Remembered.

  The number of times of potential supply stored in the number storage means is decremented by the decrement means every time potential supply is performed. Thereby, the potential supply by the first supply means is performed until the number of times stored in the number storage means becomes “0”.

  According to the above-described configuration, not only can the potential supply by the first supply unit to each pixel be suitably performed, but also the determination unit preferably determines whether or not the potential supply by the first supply unit is being performed. Is possible. Therefore, the contour image can be erased at an appropriate timing.

  In another aspect of the control apparatus for an electro-optical device according to the present invention, flag information indicating whether or not the potential supply by the first supply unit is to be performed for each of the plurality of pixels is performed in frame period units. A plurality of flag storage means for storing is provided.

  According to this aspect, for example, flag information indicating whether or not potential supply by the first supply unit should be performed on each of the plurality of pixels is stored by a plurality of flag storage units configured by a RAM or the like. Specifically, for example, when i rows and j columns of pixels are arranged on the display unit, the flag storage means is configured to have i × j storage areas. In the flag storage means corresponding to the first frame period among the plurality of flag storage means, “1” is stored in the storage area corresponding to the pixel to be supplied with the potential in the first frame period. “0” is stored in the storage area corresponding to the pixel to which no potential is supplied in the frame. Similarly, in the flag storage unit corresponding to the second frame period (that is, the frame period subsequent to the first frame period) among the plurality of flag storage units, the pixel to be supplied with the potential in the second frame period “1” is stored in the corresponding storage area, and “0” is stored in the storage area corresponding to the pixel to which no potential is supplied in the second frame. The first supply means supplies the potential in each frame period in accordance with such flag information.

  According to the configuration described above, not only can the potential supply to each pixel be suitably performed, but also the determination unit can suitably determine whether or not the potential supply by the first supply unit is being performed. Therefore, the contour image can be erased at an appropriate timing.

  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 control device for the electro-optical device according to the present invention described above is provided, it is possible to reduce the afterimage after contour rewriting. 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 a first embodiment. It is a block diagram which shows the structure of the display part periphery of the electrophoretic display device which concerns on 1st Embodiment. FIG. 3 is an equivalent circuit diagram illustrating an electrical configuration of a pixel according to the first embodiment. It is a fragmentary sectional view of the display part of the electrophoretic display device concerning a 1st embodiment. It is a block diagram which shows the detailed structure of the controller which concerns on 1st Embodiment. 3 is a flowchart showing a schematic operation of the electrophoretic display device according to the first embodiment. It is a flowchart which shows the operation | movement at the time of the writing of the controller which concerns on 1st Embodiment. It is a conceptual diagram (the 1) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 1st Embodiment. It is a conceptual diagram (the 2) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 1st Embodiment. FIG. 6 is a conceptual diagram (part 3) illustrating a method of applying a voltage to each pixel of the electrophoretic display device according to the first embodiment. FIG. 6 is a conceptual diagram (part 4) illustrating a method of applying a voltage to each pixel of the electrophoretic display device according to the first embodiment. FIG. 6 is a conceptual diagram (part 5) illustrating a method of applying a voltage to each pixel of the electrophoretic display device according to the first embodiment. It is a conceptual diagram (the 6) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 1st Embodiment. It is a conceptual diagram (the 7) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 1st Embodiment. It is a conceptual diagram (the 8) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 1st Embodiment. It is a top view which shows an example of the image before rewriting, and the image after rewriting. 3 is a flowchart showing a contour afterimage erasing operation in the electrophoretic display device according to the first embodiment. It is a top view which shows an example of the difference image of the image before rewriting, and the image after rewriting. It is a table figure which shows the voltage applied to a pixel at the time of image rewriting for every area | region. It is a schematic diagram for demonstrating generation | occurrence | production of the blur of the boundary part in a display image. It is a top view which shows an example of the outline image extracted so that it may correspond to an outline afterimage. It is a table figure which shows the voltage applied to an outline display pixel at the time of an outline erasing operation for every area | region. It is a time chart (the 1) which shows the execution timing of an image rewriting operation | movement and an outline erasing operation | movement. It is a time chart (the 2) which shows the execution timing of image rewriting operation | movement and outline erasing operation | movement. It is a block diagram which shows the detailed structure of the controller which concerns on 2nd Embodiment. It is a flowchart which shows the operation | movement at the time of writing of the controller which concerns on 2nd Embodiment. It is a conceptual diagram (the 1) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. It is a conceptual diagram (the 2) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. It is a conceptual diagram (the 3) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. It is a conceptual diagram (the 4) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. It is a conceptual diagram (the 5) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. It is a conceptual diagram (the 6) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. It is a conceptual diagram (the 7) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. It is a conceptual diagram (the 8) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. It is a conceptual diagram (the 9) which shows the voltage application method to each pixel of the electrophoretic display device which concerns on 2nd Embodiment. 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>
First, the electro-optical device according to the present embodiment will be described with reference to FIGS. In the following embodiments, an electrophoretic display device will be described as an example of an electro-optical device according to the present invention.

<First Embodiment>
The overall configuration of the electrophoretic display device according to the first 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 the first embodiment.

  In FIG. 1, an electrophoretic display device 1 according to the present embodiment includes a display unit 3, a VRAM 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. A specific configuration of the display unit will be described in detail later.

  The VRAM 4 is a frame buffer and stores frame image data based on the control of the CPU 100.

  The RAM 5 includes a write information storage area 6 and a scheduled image data storage area 7. The write information recording area 6 stores write information indicating whether or not writing is performed for each pixel. The scheduled image data storage area 7 stores data of a scheduled image that is displayed when writing currently performed on each pixel is completed.

  The controller 10 controls the display unit 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. In particular, the CPU 100 stores image data to be displayed on the display unit 3 in the VRAM 4.

  FIG. 2 is a block diagram illustrating a configuration around the display unit of the electrophoretic display device according to the first 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 VH (for example, +15 volt), or a low potential VL (for example, -15 volt). As will be described later, in the present embodiment, the above-described partial rewrite drive is employed.

  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 first 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 first 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 9a. 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, alicyclic 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, a specific configuration of the controller according to the present embodiment will be described with reference to FIG.

  FIG. 5 is a block diagram illustrating a detailed configuration of the controller according to the first embodiment.

  In FIG. 5, the controller 10 includes a rewrite determination unit 201, a write state determination unit 202, a write control unit 203, a write information update unit 204, a scheduled image data update unit 205, a contour image extraction unit 206, and a contour afterimage deletion control unit 207. It is prepared for.

  The rewrite determination unit 201 compares the pixel data of the display image stored in the VRAM 4 with the pixel data of the planned image stored in the planned image data storage area 7 for each pixel 20 and if both are different, It is determined that the writing for reflecting the display image data stored in the VRAM 4 (hereinafter referred to as “new writing” as appropriate) should be performed on the pixel.

  The writing state determination unit 202 refers to the writing information stored in the writing information storage area 6 for each pixel 20 and determines whether the writing operation is in progress.

  The writing control unit 203 performs control to start a new writing when it is determined that a new writing should be performed for one pixel and it is determined that a writing operation is not in progress.

  When the new writing is started, the writing information update unit 204 changes the writing information of the pixel to a value indicating that the writing operation is in progress. In addition, when the ongoing write operation is completed, the write information update unit 204 changes the pixel write information to a value indicating that the write operation is not in progress.

  The scheduled image data update unit 205 overwrites the scheduled image data of the pixels stored in the scheduled image data storage area with the pixel data of the display image stored in the VRAM 4 when a new writing is started.

  The contour image extraction unit 206 is an example of the “extraction unit” of the present invention, and extracts a contour image that constitutes a contour afterimage from pixel data before rewriting and pixel data after rewriting. The contour image will be described in detail later.

  The contour afterimage erasure control unit 207 is an example of the “contour erasure unit” of the present invention, and controls to apply a voltage for erasing the contour image to the contour display pixel that displays the contour image.

  Next, the operation at the time of image rewriting in the electrophoretic display device according to the present embodiment will be described with reference to FIGS. In the following, for convenience of explanation, the operation for erasing the contour afterimage is omitted, and only the operation for rewriting the image is described in detail. The contour afterimage erasing operation will be described in detail later.

  FIG. 6 is a flowchart showing a schematic operation of the electrophoretic display device according to the first embodiment.

  In FIG. 6, when the electrophoretic display device according to the first embodiment is operated, first, the display image data to be displayed on the display unit 3 is stored in the VRAM 4 by the CPU 100 (step S1).

  Subsequently, in the rewrite determination unit 201 in the controller 10, for one pixel 20, the pixel data of the display image stored in the VRAM 4 matches the pixel data of the planned image stored in the planned image data storage area 7. Is determined (step S2).

  Here, when the pixel data of the display image stored in the VRAM 4 and the pixel data of the planned image stored in the planned image data storage area 7 match (step S2: YES), the pixel data for one pixel is stored. New writing is determined to be unnecessary, and the process proceeds to the next pixel processing. On the other hand, when the pixel data of the display image stored in the VRAM 4 and the pixel data of the planned image stored in the planned image data storage area 7 are different (step S2: NO), one pixel is selected. Determine that a new write should be done.

  If it is determined that new writing should be performed, the writing state determination unit 202 refers to the writing information stored in the writing information storage area 6 for one pixel 20 and determines whether the writing operation is in progress. Is determined (step S3).

  If it is determined that the writing operation is not in progress (step S3: NO), the writing control unit 203 starts a new writing (step S4). At this time, the writing information update unit 204 changes the writing information of the pixel to a value indicating that the writing operation is in progress. Further, the scheduled image data update unit 205 overwrites the scheduled image data of the pixels stored in the scheduled image data storage area with the pixel data of the display image stored in the VRAM 4. On the other hand, when it is determined that the write operation is in progress (step S3: YES), the write control unit 203 continues the write operation in progress (step S5). Note that the write information update unit 204 changes the pixel write information to a value indicating that the write operation is not in progress when the ongoing write operation is completed.

  FIG. 7 is a flowchart showing an operation at the time of writing by the controller according to the first embodiment.

  Here, in the write information storage area 6, first write information indicating whether or not a write operation for changing the display state of each pixel 20 from black to white is in progress, and each pixel 20. It is assumed that second write information indicating whether or not a write operation for changing the display state from white to black is in progress is included.

  Further, it is assumed that the writing operation for changing the display state of each pixel 20 from white to black or from black to white includes a plurality of frame periods. Therefore, for example, a writing operation for changing the display state from white to black is an operation of supplying a data signal for displaying black to the pixel 20 a plurality of times (that is, a data signal in each of a plurality of frame periods). Supply operation). FIG. 7 shows an operation in one frame period among the plurality of frame periods.

  The first and second write information described above is a value that fluctuates with the number of times the drive voltage has already been applied in the write operation, and after the last drive voltage is applied in the write operation, the write information progresses in the write operation. The value indicates that it is not in the middle. Here, the writing information is the remaining number of application times until the writing is completed. Therefore, here, the remaining application count “0” corresponds to a value indicating that the writing operation is not in progress, and a value other than “0” corresponds to a value indicating that the writing operation is in progress. The write information storage area 6 here is an example of the “number of times storage means” in the present invention.

  In FIG. 7, during the operation of the electrophoretic display device according to the first embodiment, first, the writing state determination unit 202 firstly stores the first and second writing information stored in the writing information storage area 6 for one pixel 20. (That is, the remaining number of application times) is referred to (step S11).

  If at least one of the first and second write information is other than “0” (step S11: YES), the write control unit 203 continues the ongoing write operation (step S12). Further, the write information update unit 204 decrements the value of the remaining number of applications every time voltage is applied once (step S14). That is, the write information update unit 204 here is an example of the “decrement unit” in the present invention.

  On the other hand, when the values of both the first and second write information are “0” (step S11; NO), the pixel data of the display image stored in the VRAM 4 of the pixel 20 by the rewrite determining unit 201. Then, it is determined whether or not the pixel data of the scheduled images stored in the scheduled image data storage area 7 match each other (step S13).

  If the two are different (step S13: NO), the write information update unit 204 registers the number of times of voltage application required for the write operation in the write information storage area 6 (step S15). Subsequently, the scheduled image data update unit 205 overwrites the scheduled image data stored in the scheduled image data storage area 7 of the pixel 20 with the pixel data of the display image stored in the VRAM 4 (step S16). . Further, the write control unit 203 starts a new write operation (step S17).

  After performing the above operation for all the pixels 20, the controller 10 transmits the drive waveform of the current frame period to the display unit 3 (step S18).

  Next, the image rewriting operation of the electrophoretic display device 1 according to the present embodiment will be described more specifically with reference to FIGS.

  FIGS. 8 to 15 are conceptual diagrams showing a method of applying a voltage to each pixel of the electrophoretic display device according to the first embodiment. 8 to 15, some pixels in the display unit 3 are shown as Pij (where i represents a row number and j represents a column number). In each pixel Pij, gradation is expressed in eight levels from “0” corresponding to black to “7” corresponding to white.

  The write information storage area 6 includes a white write information storage area 6A indicating whether or not a write operation for changing the display state of each pixel from black to white is in progress, and the display state of each pixel from white to black. A black writing information storage area 6B indicating whether or not a writing operation for changing is in progress is included.

  In the VRAM 4, the white writing information storage area 6A, the black writing information storage area 6B, and the scheduled image data storage area 7, a storage area corresponding to the pixel Pij of the display unit 3 is provided.

  The storage area Mij of the VRAM 4 stores pixel data (that is, gradation) of the display image, and the storage area Mij of the scheduled image data storage area 7 stores pixel data (that is, gradation) of the scheduled image. It is remembered.

  The storage area Mij of the white writing information storage area 6A stores the number of times of voltage application (0 to 7) required for each pixel Pij to display white. The storage area Mij of the black writing information storage area 6B is stored in the storage area Mij. Stores the number of times (0 to 7) of voltage application required until each pixel Pij is displayed in black. The number of times of voltage application here can be read as the number of frames for applying voltage.

  In the state shown in FIG. 8, rewriting from the display image A to the scheduled image stored in the scheduled image data storage area 7 is in progress, and the pixels P11, P12, P21, and P22 are rewritten from black to white. The remaining number of times “7” is set in each of the storage areas M11, M12, M21, and M22 of the write information storage area 6A. Similarly, since the pixels P33, P34, P43, and P44 are rewritten from white to black, the remaining number of times “7” is set in the storage areas M33, M34, M43, and M44 of the black writing information storage area 6B.

  FIG. 9 shows a state in which one writing operation, that is, a writing operation for one frame is completed from the state of FIG. 8, and the pixels P11, P12, P21, and P22 are in the white direction by one gradation. The pixels P33, P34, P43, and P44 are modulated in the black direction by one gradation. Further, the remaining number of storage areas M11, M12, M21, and M22 of the white writing information storage area 6A and the remaining number of storage areas M33, M34, M43, and M44 of the black writing information storage area 6B are decreased by 1 respectively to “6”. "It has become.

  Thus, each time a writing operation is performed, the gradation of the pixel Pij is modulated one step at a time, and the remaining number of times of the white writing information storage area 6A and the black writing information storage area 6B is also subtracted by one.

  FIG. 10 shows a state at the end of the third write operation from the state of FIG. Consider a case where the image data of the VRAM 4 is changed by the CPU 100 as shown in FIG.

  In this case, the writing state determination unit 202 refers to the remaining number of times of the white writing information storage area 6A and the black writing information storage area 6B for each pixel Pij. As a result, it is determined that the writing operation is in progress for the pixels P11, P12, P21, P22, P33, P34, P43, and P44, and the writing operation is not in progress for the other pixels.

  For each pixel Pij, the rewrite determination unit 201 compares the pixel data stored in the storage area Mij of the VRAM 4 with the pixel data stored in the storage area Mij of the scheduled image data storage area 7. As a result, the pixels P21, P22, P23, P24, P31, P32, P43, and P44 are determined to be different, and the other pixels are determined to be the same.

  From the above results, the write operation currently in progress by the write control unit 203 is continued for the pixels P11, P12, P21, P22, P33, P34, P43, and P44 for which the write operation is in progress.

  For the pixels P23, P24, P31, and P32 in which the writing operation is not currently in progress and the images of the VRAM 4 and the scheduled image data storage area 7 are different, the write information storage area 6 is set by the write information update unit 203. Updated. Specifically, since the pixels P23, P24, P31, and P32 should be rewritten from white to black, the storage areas M23 and M24 of the black writing information area 6B are set to “7”, respectively.

  Further, the scheduled image data update unit 205 overwrites the storage area Mij of the scheduled image data storage area 7 with the data of the storage area Mij of the VRAM 4 for the pixels P23, P24, P31, and P32.

  As a result, the white writing information storage area 6A, the black writing information storage area 6B, and the scheduled image data storage area 7 are in the state shown in FIG.

  As shown in FIG. 11, the write control unit 203 performs the pixel P11, P12, P21, P22, P33, P34, P43, and P44 according to the information in the updated white write information storage area 6A and black write information storage area 6B. Continues the ongoing write operation and starts a new write operation for pixels P23, P24, P31 and P32.

  FIG. 12 shows a state at the time when four write operations are completed from the state of FIG. As shown in the drawing, the writing operation has been completed for the pixels P11, P12, P21, P22, P33, P34, P43, and P44, and the writing operation is in progress for the pixels P23, P24, P31, and P32.

  Here, the pixel P11, P12, P21, P22, P33, P34, P43, and P44 are determined by the writing state determination unit 202 that the writing operation is not in progress. Further, for the pixels P23, P24, P31, and P32, the rewrite determining unit 201 determines that the pixel data in the storage area Mij in the VRAM 4 and the pixel data in the storage area Mij in the scheduled image data storage area 7 do not match.

  Therefore, the write information storage area 6 is updated by the write information update unit 204 for the pixels P23, P24, P31, and P32. Specifically, since the pixels P21 and P22 should be rewritten from white to black, “7” is set in the storage areas M21 and M22 of the black writing information storage area 6B. Further, since the pixels P43 and P44 should be rewritten from black to white, "7" is set in the storage areas M43 and M44 of the white writing information storage area 6A.

  Furthermore, the scheduled image data update unit 205 overwrites the storage area Mij of the scheduled image data storage area 7 with the data of the storage area Mij of the VRAM 4 for the pixels P21, P22, P43, and P44.

  As a result, the white writing information storage area 6A, the black writing information storage area 6B, and the scheduled image data storage area 7 are in the state shown in FIG.

  As shown in FIG. 13, the write control unit 203 continues the write operation in progress for the pixels P23, P24, P31, and P32 according to the information in the updated white write information storage area 6A and the black write information storage area 6B. Then, a new writing operation is started for the pixels P21, P22, P43, and P44.

  FIG. 14 shows a state at the time when three write operations are completed from the state of FIG. As shown in the figure, the writing operation has been completed for the pixels P23, P24, P31, and P32, and the writing operation is in progress for the pixels P21, P22, P43, and P44.

  FIG. 15 shows a state at the time when three write operations are completed from the state of FIG. As shown in the figure, the writing operation is completed for the pixels P21, P22, P43, and P44, and the drawing of the image stored in the VRAM 4 is completed.

  In the above image rewriting, the writing operation for changing the display state of each pixel from black to white or from white to black is applied to the pixel electrode 21 of the pixel (first pixel) whose gradation to be displayed changes. A step of supplying a potential corresponding to the changed gradation (first supply step). In addition, in the writing operation when the display state of each pixel remains black or remains white, the potential of the counter electrode 22 is applied to the pixel electrode 21 of the pixel (second pixel) whose gradation to be displayed does not change. And a step of supplying the same potential (second supply step). Further, the controller 10, the scanning line driving circuit 60, and the data line driving circuit 70 are one mode of a first supply unit that performs the first supply step and a second supply unit that performs the second supply step.

  As described above, according to the electrophoretic display device 1 according to the first embodiment, it is determined whether or not the writing operation is in progress for each pixel, and a new writing operation is started as needed from the pixel for which writing has been completed. Therefore, in an electrophoretic display device that takes a relatively long time to rewrite an image, it is possible to improve the sensuous response speed of image display. Further, in the present embodiment, as described above, it is possible to determine whether or not the writing operation is in progress on a pixel-by-pixel basis. Therefore, the contour afterimage erasing operation described in detail below can be performed.

  Hereinafter, the contour afterimage erasing operation will be described with reference to FIGS. Here, as shown in FIG. 16, the outline afterimage erasing operation will be described with an example in which the image displayed on the display unit 3 is rewritten from the image A1 to the image A2. FIG. 16 is a plan view showing an example of the image A1 before rewriting and the image A2 after rewriting.

  FIG. 17 is a flowchart showing a contour afterimage erasing operation in the electrophoretic display device according to the first embodiment.

  In FIG. 17, at the time of the contour afterimage erasing operation, first, the contour image extraction unit 206 extracts the contour image constituting the contour afterimage (step S101). Step S101 is an example of the “extraction process” in the present invention. The contour image is extracted based on, for example, a difference image between the image A1 before rewriting and the image A2 after rewriting.

  FIG. 18 is a plan view illustrating an example of a difference image between an image before rewriting and an image after rewriting.

  As shown in FIG. 18, the difference image B between the image A1 before rewriting and the image A2 after rewriting has an area Rww in which the gradation before rewriting is white and white is retained after rewriting, and the gradation before rewriting. Is black and the area Rbb in which black is retained after rewriting, the area Rwb in which the gradation before rewriting is white and the gradation after rewriting is black, and the gradation after rewriting is black and the gradation before rewriting is black. The region is divided into four regions Rbw where the tone is white.

  FIG. 19 is a table showing the voltages applied to the pixels at the time of image rewriting for each region.

  As shown in FIG. 19, a voltage for rewriting an image is applied to each pixel 20 in the regions Rww, Rbb, Rwb, and Rbw. Specifically, 0 V, which is the reference potential GND, is applied to the regions Rww and Rbb where the gradation is to be maintained. Since no voltage is substantially applied to the regions Rww and Rbb, the number of frames to which the voltage is applied is “0”. In addition, +15 V, which is a high potential VH corresponding to black, is applied to Rwb whose gradation should be changed from white to black over seven frames. Furthermore, -15V, which is a low potential VL corresponding to white, is applied to Rbw for which the gradation is to be changed from black to white over 7 frames.

  In the above-described driving method for partially rewriting an image, there is a possibility that an afterimage may be generated in the contour portion of the erased image due to bleeding that occurs during image rewriting. Hereinafter, the principle of occurrence of bleeding described above will be described with reference to FIG.

  FIG. 20 is a schematic diagram for explaining the occurrence of blurring at the boundary in the image displayed on the display unit.

  As shown in FIG. 20, the reference potential GND is supplied as the data potential to the pixel electrode 21ww of the pixel 20ww corresponding to the region Rww (that is, the region where the gradation to be displayed remains white and does not change). When the high potential VH is supplied as the data potential to the pixel electrode 21wb of the pixel 20wb corresponding to the region wb adjacent to the pixel 20ww (that is, the region where the gradation to be displayed changes from white to black), the pixel switching transistor When 24 (see FIG. 2) is turned off, a leak current is generated between the pixel electrode 21wb and the pixel electrode 21ww, and the potential of the pixel electrode 21ww, which is the reference potential GND, is increased (ie, high There is a risk of approaching the potential VH). Therefore, in the pixel 20ww, the black particles 83 may move toward the counter electrode 22 and the white particles may move toward the pixel electrode 21ww due to a potential difference generated between the pixel electrode 21ww and the counter electrode 22. Therefore, in the pixel 20ww that should display white, a color different from white such as gray or black may be displayed. As a result, there is a risk that bleeding at the boundary between the black image portion and the white image portion in the image displayed on the display unit 3 may occur.

  FIG. 21 is a plan view showing an example of a contour image extracted so as to correspond to a contour afterimage.

  In FIG. 21, the blur located in the region Rww is not erased because no voltage is applied. For this reason, in the image A2 after rewriting, there is a possibility that a contour afterimage may occur in the region Rsw as indicated by the contour image C. The region Rsw can be extracted as a region surrounding the region Rbw in the difference image B.

  Returning to FIG. 17, when the contour afterimage is extracted, the writing state determination unit 202 determines whether or not the contour display pixel corresponding to the contour image is being written (step S102). As described above, the writing state determination unit 202 uses the value stored in the writing information storage area 6 to determine whether or not the contour display pixel is being written. Step S102 is an example of the “determination step” of the present invention, and the writing state determination unit 202 here is an example of “determination means” of the present invention.

  Here, when it is determined that the contour display pixel is not being written (step S102: NO), the contour afterimage erasure control unit 207 deletes a voltage for erasing the contour afterimage in the contour display pixel (hereinafter referred to as “contour erasure voltage” as appropriate). Is applied) (step S103). Step S103 is an example of the “contour erasing step” in the present invention. Hereinafter, the contour erasing voltage will be specifically described with reference to FIG.

  FIG. 22 is a table showing the voltages applied to the contour display pixels during the contour erasing operation for each region.

  In FIG. 22, a contour image is displayed, but -15V, which is a low potential VL corresponding to white, is applied to the region Rsw that should originally display white as a contour erasing voltage for only one frame. Although not illustrated in the contour image C shown in FIG. 21, the contour image is displayed but the region Rsb that should originally display black has a high potential VH corresponding to black as a contour erasing voltage. + 15V is applied for only one frame. Specifically, the value of the white writing information storage area 6A or the black writing information storage area 6B is changed from “0” to “1”. Note that, unlike the voltage applied at the time of image rewriting described above, the contour erasing voltage is applied only in one frame. Thereby, it can suppress or prevent that the DC balance ratio in each pixel 20 collapses.

  The application of the contour erasing voltage may be performed immediately after the determination by the writing state determination unit 202 (that is, step S102) after it is determined that the contour display pixel is not being written, or the adjacent pixels are rewritten. You may carry out according to timing. For example, the contour erasing voltage is applied to the contour display pixel in accordance with the last frame period of image rewriting performed on the pixels adjacent to the contour display pixel (that is, the last frame period among seven frames required for image rewriting). May be applied.

  More specifically, the value of the white writing information storage area 6A or the black writing information storage area 6B corresponding to the pixel adjacent to the contour display pixel is gradually decreased from “7” by applying a voltage, and “2 When “1” is changed to “1”, the value of the white writing information storage area 6A or the black writing information storage area 6B corresponding to the contour display pixel is changed from “0” to “1”. If the contour erasing voltage is applied in this way, the contour afterimage is erased at the same time as the rewriting of the image is completed, so that the contour afterimage can be made more difficult to visually recognize.

  When the writing state determination unit 202 determines that the contour display pixel is being written (step S102: YES), the contour image is erased in the frame period after the writing to the contour display pixel is completed. Is supplied with a potential. For this reason, even if the contour display pixel has undergone image rewriting at the stage where the contour erasing voltage is to be applied, the afterimage can be reliably erased as soon as the image rewriting is completed.

  FIG. 23 is a time chart (part 1) showing the execution timing of the image rewriting operation and the contour erasing operation.

  As shown in FIG. 23, the application of the contour erasure voltage described above is performed in parallel with the image rewriting. More specifically, since the writing state determination unit 202 can determine the image writing state of the contour display pixel on a pixel basis, image rewriting is not performed (that is, a potential for changing the gradation is supplied). The contour image can be erased sequentially from the pixel. As a result, when viewed on the entire display unit 3, the image rewriting operation and the contour erasing operation are driven as if each pixel proceeds simultaneously, and a state in which the contour afterimage is extremely difficult to visually recognize can be realized.

  FIG. 24 is a time chart (part 2) showing the execution timing of the image rewriting operation and the contour erasing operation.

  As shown in FIG. 24, the application of the contour erasing voltage is not performed every time image rewriting is performed, but may be performed every time image rewriting is performed a plurality of times. In this way, the afterimages generated by multiple image rewritings are erased together. It should be noted that the number of times of image rewriting that the contour erasing process is performed (that is, the value of n in the figure) is set in advance based on the contour afterimage erasing effect and the like. However, this number of times may be variable.

  When erasing the contour afterimages together, the contour afterimage is extracted as a contour image generated by a plurality of image rewritings in the above-described contour afterimage extraction in step S101. For example, if a logical sum of contour images generated in each of a plurality of image rewrites is taken, a plurality of contour images can be easily extracted.

  If the contour afterimages are erased collectively, the processing can be simplified because the number of times of applying the contour erase voltage can be reduced. Therefore, faster image display can be realized.

  As described above, according to the electrophoretic display device according to the first embodiment, it is possible to effectively suppress the occurrence of the afterimage in the image displayed on the display unit 3. Therefore, a high quality image can be displayed.

Second Embodiment
Next, an electrophoretic display device according to a second embodiment will be described with reference to FIGS. 25 to 35. Note that the second embodiment differs from the first embodiment described above only in part of the configuration and control, and the other parts are substantially the same. For this reason, below, a different part from 1st Embodiment is demonstrated in detail, and description shall be abbreviate | omitted suitably about the overlapping part.

  First, the configuration of the controller 10 according to the second embodiment will be described with reference to FIG.

  FIG. 25 is a block diagram illustrating a detailed configuration of the controller according to the second embodiment.

  In FIG. 25, the controller 10 according to the second embodiment includes an additional write information calculation unit 208 and a processing target determination unit 209 in addition to the parts included in the controller 10 (see FIG. 5) according to the first embodiment described above. Configured.

  When the rewriting determination by the rewriting determination unit 201 determines that the scheduled image data recording area 7 should be updated, the additional writing information calculation unit 208 displays the pixel data of the display image stored in the VRAM 4 and the scheduled image data. The difference from the pixel data of the scheduled image stored in the storage area 7 is calculated, and the pixel data based on the calculated difference is stored in the additional write information storage area 8 (see FIG. 27 and the like) described later.

  The process target determination unit 209 determines which storage area should be referred to at the application time of each drive voltage among a plurality of write information storage areas 6 (see FIG. 27 and the like) described later.

  Next, details of the write information storage area 6 will be described.

  Unlike the first embodiment, four write information storage areas 6 according to the second embodiment are prepared as can be seen from FIG. This number corresponds to the number of times of applying the drive voltage for changing the display state of the pixel 20 from black to white or from white to black. That is, in the first embodiment, the drive voltage is applied seven times in order to change the display state of the pixel 20 from black to white or from white to black. In the second embodiment, the drive voltage is applied four times. To do.

  Each of the four write information storage areas 6 stores flag information for identifying whether or not each pixel 20 is an application target of a drive voltage. For example, flag information is ON when the drive voltage is to be applied, and flag information is OFF when the drive voltage is not to be applied. Further, in the write information storage area 6, whether the flag information includes a drive voltage for changing the display state of each pixel 20 from black to white or a drive voltage for changing from white to black. Information is stored in association with each other.

  In addition, when one pixel 20 is an object to be applied with a drive voltage, it means that a writing operation for the pixel 20 is in progress, and when one pixel 20 is not an object to be applied with a drive voltage, This means that the writing operation for the pixel 20 is not in progress. Therefore, the write information storage area 6 stores write information indicating whether or not a write operation for changing the display state of each pixel is in progress.

  Hereinafter, flag information for identifying whether or not the pixel 20 is a target for applying the drive voltage, and information indicating that the application of the drive voltage is to change the display state of the pixel 20 from black to white. Are collectively referred to as first write information. Further, flag information for identifying whether or not the pixel 20 is a target to which the drive voltage is applied, and information indicating that the application of the drive voltage is to change the display state of the pixel 20 from white to black. Together, this is called second write information. The first write information and the second write information are collectively referred to as write information. The write information storage area 6 according to the second embodiment is an example of the “flag storage unit” in the present invention.

  Here, the reason why the same number of write information storage areas 6 as the number of times of application of the drive voltage for changing the display state of the pixels 20 is prepared is as follows.

  For example, the writing operation for changing the display state of the pixel 20 from white to black is an operation of supplying the data signal for displaying black to the pixel 20 four times (that is, the driving voltage is set to 4 for the pixel 20). The operation of applying the voltage twice). That is, the writing operation for changing the display state of the pixel 20 from white to black includes four frame periods. A write information recording area 6 is prepared corresponding to each of the four frame periods.

  The write control unit 203 sequentially refers to each write information storage area 6 every time the data signal is supplied (that is, when the drive voltage is applied to the pixel 20), and the write information storage area 6 thus referred to is referred to. The data signal is supplied to each pixel 20 based on the contents stored in the. Specifically, among the four write information storage areas 6, in the write information storage area 6 to be referred to in the first frame period, the flag information of a certain pixel 20 is ON, and the display state of the pixel 20 Is changed from white to black, the writing control unit 203 supplies a data signal for displaying black to the pixel. In the write information storage area 6 to be referred to in the next frame period, when the flag information of a certain pixel 20 is ON and the display state of the pixel 20 is changed from white to black. The writing control unit 204 again supplies a data signal for displaying black to the pixel. In this way, when the reference to the four write information storage areas 6 corresponding to the four frame periods is finished, the reference object becomes the first write information storage area 6 again. Thus, one write information storage area 6 corresponds to one frame period described above.

  Next, the operation at the time of image rewriting in the electrophoretic display device according to the second embodiment will be described with reference to FIG. In the following, for convenience of explanation, the operation for erasing the contour afterimage is omitted, and only the operation for rewriting the image is described in detail.

  FIG. 26 is a flowchart showing an operation at the time of writing by the controller according to the second embodiment.

  In FIG. 26, during the operation of the electrophoretic display device according to the second embodiment, first, the display image data to be displayed on the display unit 3 is stored in the VRAM 4 by the CPU 100 (step S21).

  Subsequently, in the rewrite determination unit 201 in the controller 10, for one pixel 20, the pixel data of the display image stored in the VRAM 4 matches the pixel data of the planned image stored in the planned image data storage area 7. Is determined (step S22).

  Here, when the pixel data of the display image stored in the VRAM 4 and the pixel data of the planned image stored in the planned image data storage area 7 match (step S22: YES), the writing control unit 203 A write operation is started based on the write contents stored in the write information storage area 6 (step S28). On the other hand, when the pixel data of the display image stored in the VRAM 4 and the pixel data of the planned image stored in the planned image data storage area 7 are different (step S22: NO), the writing state determination unit 202 Referring to the first and second write information stored in the write information storage area 6 to be referred to, it is determined whether or not the write operation is in progress for the corresponding pixel data (step S23).

  Here, if the write operation is in progress (step S23: YES), the write control unit 203 continues the write operation in progress (step S24), and proceeds to the process of step S29. On the other hand, if the writing operation is not in progress for the corresponding pixel data (step S2: NO), the additional writing information calculation unit 208 stores the display image pixel data stored in the VRAM 4 and the scheduled image data storage area 7. The difference from the stored pixel data of the scheduled image is calculated, and the pixel data based on this difference is stored in the additional write information storage area 8 (step S25).

  Subsequently, the write control unit 203 registers write information for the target pixel 20 in the write information storage area 6 based on the pixel data stored in the additional write information storage area 8 (step S26).

  Next, the scheduled image data update unit 205 writes all scheduled image data stored in the scheduled image data storage area 7 in accordance with the contents of writing stored in the write information storage area 6. Update with the pixel data of the scheduled image when finished (step S27).

  Further, the write control unit 203 starts a write operation based on the write contents stored in the write information storage area 6 (step S28), and then proceeds to step S29.

  The processing target determination unit 209 determines whether or not there is an additional pixel 20 to which the drive voltage is applied in the current writing information storage area 6 to be referred to (step S29). Here, when there are more pixels 20 to which the drive voltage is applied (step S29: YES), the processing target determination unit 209 advances the processing target pixel to the next pixel in the same write information storage area 6. (Step S30), the process returns to Step S2. On the other hand, when there are no more pixels 20 to which the drive voltage is applied (step S29: NO), the processing target determination unit 209 transmits an image signal or the like according to the current writing information storage area 6 to the display unit 3. (Step S31), the write information storage area 6 to be referred is advanced to the next write information storage area 6 (Step S32).

  Next, the image rewriting operation of the electrophoretic display device according to the second embodiment will be described more specifically with reference to FIGS.

  FIGS. 27 to 35 are conceptual diagrams showing a method of applying a voltage to each pixel of the electrophoretic display device according to the second embodiment. In FIG. 27 to FIG. 35, some pixels in the display unit 3 are shown as Pij (where i represents a row number and j represents a column number). In each pixel Pij, gradation is expressed in five levels from “0” corresponding to black to “4” corresponding to white.

  As described above, in this embodiment, four frames are used for gradation change from white to black or from black to white. Therefore, the write information storage area 6 includes a total of four write information storage areas 6A to 6D corresponding to each frame. Note that the numbers (1), (2), (3), and (4) given to the write information storage areas 6A to 6D indicate the reference order.

  The VRAM 4 and the scheduled image data storage area 7 are provided with storage areas Mij corresponding to the pixels Pij of the display unit 3, respectively. The storage area Mij of the VRAM 4 stores pixel data (that is, gradation) of the display image, and the storage area Mij of the scheduled image data storage area 7 stores pixel data (that is, gradation) of the scheduled image. It is remembered.

  In the write information storage areas 6A to 6D, storage areas Mij for storing write information corresponding to the pixels Pij of the display unit 3 are provided.

  Based on the image data stored in the VRAM 4, the controller 10 performs the writing information storage area 6 </ b> A, the writing information storage area 6 </ b> B, the writing information storage area 6 </ b> C, and the writing information storage area 6 </ b> D in this order. “1” is stored as write information in the storage area Mij. When writing to the pixel Pij of the display unit 3 is performed based on the writing information stored in the writing information storage area 6D, the writing information storage area 6A becomes a recording area for writing information. Note that “1” shown in the figure is flag information “ON”, which means that the drive voltage is to be applied.

  In FIG. 27, since the pixels P11, P12, P21, and P22 are rewritten from white to black, “1” is stored in the storage areas M11, M12, M21, and M22 of the write information storage areas 6A to 6D. In this case, since rewriting is performed from white to black, the write information stored in the storage areas M11, M12, M21, and M22 corresponds to the second write information.

  FIG. 28 shows a state in which the writing operation for one frame is completed from the state of FIG. In FIG. 28, the writing content of the writing information storage area 6A in FIG. 7 is reflected in the pixels P11, P12, P21, and P22.

  FIG. 29 shows a state in which the writing operation for two frames is completed from the state of FIG. That is, the writing contents of the writing information storage area 6B in FIG. 28 are reflected in the pixels P11, P12, P21, and P22. In the following, a case is considered where there is a difference between the image data stored in the VRAM 4 by the CPU 100 and the image data stored in the scheduled image storage area 7 at this timing.

  In FIG. 29, for each pixel Pij, the rewrite determination unit 201 includes pixel data stored in each of the storage areas Mij of the VRAM 4 and pixel data stored in each of the storage areas Mij of the scheduled image data storage area 7. Compare As a result, the rewrite determination unit 201 determines that the storage areas M11, M12, M33, and M43 are different from each other, and determines that the other storage areas are the same.

  Next, the writing state determination unit 202 refers to the writing information in each of the storage areas Mij stored in the writing information storage areas 6A to 6D for each pixel Pij. As a result, the writing state determination unit 202 determines that the writing operation is in progress for the pixels P11, P12, P21, and P22, and the writing operation is not in progress for the other pixels. Accordingly, the writing operation is continued for the pixels P11, P12, P21, and P22 for which the writing operation is in progress.

  Next, the additional writing information calculation unit 208 stores the pixel data stored in each of the storage areas Mij of the VRAM 4 and the storage area Mij of the scheduled image data storage area 7 based on the comparison in the rewrite determination unit 201. The difference from the calculated pixel data is calculated, and the pixel data based on the calculated difference is stored in the additional writing information storage area 8.

  The writing control unit 203 updates the contents of the writing information storage area 6 based on the image data stored in the additional writing information storage area 8. Specifically, since the pixels P33 and P43 should be rewritten from white to black, the write control unit 203 performs the second operation on each of the storage areas M33 and M43 in the write information recording areas 6A to 6D. As the write information, information indicating that the drive voltage is to be changed from white to black is registered.

  The pixels P11 and P22 should be rewritten from black to white. However, since the writing state determination unit 202 determines that the writing operation is in progress for the pixels P11 and P21, In the write information storage area 6, the storage areas M11 and M21 corresponding to the pixels P11 and P21 are not updated.

  Next, the pixel when the scheduled image data update unit 205 completes the writing of the storage area Mij of the scheduled image data storage area 7 according to the writing contents stored in the writing information storage area 6. Update with data. As a result of such write control, the write information storage areas 6A to 6D and the scheduled image data storage area 7 are in the state shown in FIG.

  In FIG. 30, the write control unit 203 continues the write operation in progress for the pixels P11, P12, P21, and P22 according to the information in the updated write information storage area 6C, and performs a new write for the pixels P33 and P43. Start operation. As described above, when the image data stored in the VRAM 4 is rewritten from the state of FIG. 28 to the states of FIGS. 29 and 30, the pixels P11, P12, P21, and P22 based on the image data of the VRAM 4 of FIG. Even if the writing operation is continued, writing based on the image data of the VRAM 4 in FIGS. 29 and 30 can be started in some pixels (that is, P33 and P43). Thereby, a bodily response speed can be improved.

  FIG. 31 shows a state at the time when the writing operation for two frames is completed from the state of FIG. As shown in the drawing, the writing operation from white to black is completed for the pixels P11, P12, P21, and P22, and the writing operation from white to black is in progress for P33 and P43. In FIG. 31, the writing control unit 203 has updated the writing information storage area 6 based on the pixel data stored in the additional writing information storage area 8. Specifically, since writing from black to white should be performed for the pixels P11 and P21, the writing control unit 203 applies the first to each of the storage areas M11 and M21 in the writing information storage areas 6A to 6D. 1 write information is registered.

  FIG. 32 shows a state at the time when the writing operation for three frames is completed from the state of FIG. As shown in the drawing, the writing operation has been completed for the pixels P33 and P43. At this timing, the VRAM is updated by the CPU 100 as shown in the figure, and the difference between the image data stored in the VRAM 4 and the image data stored in the scheduled image data storage area 7 occurs. Think.

  In FIG. 32, the writing state determination unit 202 refers to the writing information in each of the storage areas Mij stored in the writing information storage areas 6A to 6D for each pixel Pij. As a result, the writing state determination unit 202 determines that the writing operation is in progress for the pixels P11 and P21 and that the writing operation is not in progress for the other pixels. Thereby, the writing operation is continued for the pixels P11 and P21 in which the writing operation is in progress.

  Further, in FIG. 32, the rewrite determining unit 201 for each pixel Pij, pixel data stored in each of the storage areas Mij of the VRAM 4 and pixel data stored in each of the storage areas Mij of the scheduled image data storage area 7. And compare. As a result, the rewrite determining unit 201 determines that the storage areas M12, M21, and M31 are different from each other, and determines that the other storage areas are the same.

  Next, the writing state determination unit 202 refers to the writing information in each of the storage areas Mij stored in the writing information storage areas 6A to 6D for each pixel Pij. As a result, the writing state determination unit 202 determines that the writing operation is in progress for the pixels P11 and P21 and that the writing operation is not in progress for the other pixels.

  Next, the additional writing information calculation unit 208 stores the pixel data stored in each of the storage areas Mij of the VRAM 4 and the storage area Mij of the scheduled image data storage area 7 based on the comparison in the rewrite determination unit 201. The difference from the calculated pixel data is calculated, and the pixel data based on the calculated difference is stored in the additional writing information storage area 8.

  The writing control unit 203 updates the contents of the writing information storage area 6 based on the image data stored in the additional writing information storage area 8. Specifically, since the pixel P12 should be rewritten from black to white, the write control unit 203 registers the first write information in the storage area M31 in the write information recording areas 6A to 6D. .

  In addition, the pixel P21 should be rewritten from white to black, but the writing state determination unit 202 determines that the writing operation is in progress for the pixel P21. In the storage area 6, the storage areas M11 and M21 corresponding to the pixel P21 are not updated.

  Next, the pixel when the scheduled image data update unit 205 completes the writing of the storage area Mij of the scheduled image data storage area 7 according to the writing contents stored in the writing information storage area 6. Update with data. As a result of such write control, the write information storage areas 6A to 6D and the scheduled image data storage area 7 are in the state shown in FIG.

  In FIG. 33, the write control unit 203 continues the write operation in progress for the pixels P11 and P21 and starts a new write operation for the pixels P12 and P31 according to the information in the updated write information storage area 6D. .

  FIG. 34 shows a state at the time when the writing operation for one frame is completed from the state of FIG. As shown in the drawing, the writing operation from black to white has been completed for the pixels P11 and P21, and the writing operation from black to white is in progress for the pixel P12. In FIG. 34, the write control unit 203 has updated the write information storage area 6 based on the pixel data stored in the additional write information storage area 8. Specifically, since writing from white to black should be performed for the pixel P21, the write control unit 203 registers the second write information in the storage area M21 in the write information storage areas 6A to 6D. To do.

  The scheduled image data update unit 205 also updates the scheduled image data in the scheduled image data storage area 7 based on the contents of the writing stored in the writing information storage area 6 based on the updated contents of the writing information storage area 6. The writing control unit 203 updates the pixel data when all writing is completed.

  FIG. 35 shows a state at the time when the writing operation for four frames is completed from the state of FIG. As shown in the figure, all writing operations have been completed, and the image data in the display image A is the same as the image data stored in the VRAM 4.

  As described above, according to the second embodiment, it is determined whether or not the writing operation is in progress in units of pixels, and a new writing operation is started as needed from the pixel 20 for which writing has been completed. In an electrophoretic display device that takes a relatively long time to rewrite an image, the perceived response speed of image display can be improved. Further, in the present embodiment, as described above, since it can be determined whether or not the writing operation is in progress in units of pixels, it is possible to perform the contour afterimage erasing operation similar to the first embodiment. That is, also in the second embodiment, the contour afterimage erasing operation described with reference to FIGS. 16 to 24 can be performed.

  Here, the second embodiment differs from the first embodiment in the configuration of storage areas used for image rewriting and the control method using them. However, also in the second embodiment, it is possible to determine whether or not the writing operation is in progress in units of pixels as in the first embodiment, and therefore, the contour erasing voltage can be applied by the same method. Specifically, the first write information or the second write information may be registered for the write information storage areas 6A to 6D corresponding to the frame period to which the contour erasing voltage is to be applied.

  As described above, according to the electrophoretic display device according to the second embodiment, it is possible to effectively suppress the occurrence of a contour afterimage in the image displayed on the display unit 3 as in the first embodiment. It is. Therefore, a high quality image can be displayed.

<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. 36 is a perspective view illustrating a configuration of the electronic paper 1400.

  As illustrated in FIG. 36, 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. 37 is a perspective view showing a configuration of an electronic notebook 1500.

  As shown in FIG. 37, an electronic notebook 1500 is obtained by bundling a plurality of electronic papers 1400 shown in FIG. 36 and sandwiching them between covers 1501. 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.

  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 any device as long as it has a display element that can generate a contour afterimage as in the above-described embodiment. For example, the electro-optical device may be an electro-optical device using an electronic powder fluid.

  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 ... VRAM, 5 ... RAM, 6 ... Write information storage area, 7 ... Planned image data storage area, 8 ... Additional write information storage area, 10 ... Controller, 20 ... Pixel, 21 ... Pixel electrode, 22 Reference electrode, 24 ... Transistor for pixel switching, 28 ... Element substrate, 29 ... Counter substrate, 40 ... Scanning line, 50 ... Data line, 60 ... Scanning line drive circuit, 70 ... Data line drive circuit, 82 ... White particle, 83 ... Black particles, 100 ... CPU, 201 ... Rewrite determination unit, 202 ... Write state determination unit, 203 ... Write control unit, 204 ... Write information update unit, 205 ... Planned image data update unit, 206 ... Contour image extraction unit, 207 ... Contour afterimage erasure control unit, 208 ... Additional write information calculation unit, 209 ... Processing target determination unit, 220 ... Common potential supply circuit, VL ... Low potential, V ... high potential, GND ... reference potential, Rwb, Rbw, Rww, Rbb ... area, Pij ... pixel, Mij ... storage area.

Claims (10)

A display unit provided corresponding to the intersection of a plurality of scanning lines and a plurality of data lines crossing each other, and a pixel electrode facing each other and a plurality of pixels each having an electro-optic material between the counter electrodes; A drive unit configured to supply a plurality of potentials to supply a data potential corresponding to the image data to the pixel electrode of each of the plurality of pixels during a predetermined frame period in order to display an image corresponding to the image data; A control method for controlling an electro-optical device provided,
A first supply step of supplying a potential corresponding to the changed gradation to the pixel electrode of the first pixel in which the gradation to be displayed changes when rewriting an image displayed on the display unit. When,
A second supply step of supplying the same potential as the potential of the counter electrode to the pixel electrode of the second pixel whose gradation to be displayed does not change during the image rewriting;
An extraction step of extracting a contour image from the difference between the image before image rewriting and the image after image rewriting;
A determination step of determining whether or not the first supply step is performed in pixel units for the contour display pixels that display the contour image;
A contour erasing step of supplying a potential for erasing the contour image to the pixel electrode of the pixel that is determined not to be subjected to the first supply step among the contour display pixels. Control method of electro-optical device.   In the contour erasing step, the pixel electrode of the pixel that is determined not to be subjected to the first supply step among the contour display pixels is applied to pixels adjacent to each other. The method for controlling the electro-optical device according to claim 1, wherein a potential for erasing the contour image is supplied in a last frame period.   In the contour erasing step, the contour image is applied to the pixel electrode of the pixel that is determined to have undergone the first supply step among the contour display pixels in a frame period after the first supply step is completed. The method for controlling the electro-optical device according to claim 1, wherein a potential for erasing data is supplied.   4. The method of controlling an electro-optical device according to claim 1, wherein the contour erasing step is performed once for a plurality of times of image rewriting.   2. The period for supplying a potential for erasing the contour image in the contour erasing step is shorter than a period for supplying a potential corresponding to the changed gradation in the first supply step. 5. The method for controlling the electro-optical device according to claim 1. A display unit provided corresponding to the intersection of a plurality of scanning lines and a plurality of data lines crossing each other, and a pixel electrode facing each other and a plurality of pixels each having an electro-optic material between the counter electrodes; A drive unit configured to supply a plurality of potentials to supply a data potential corresponding to the image data to the pixel electrode of each of the plurality of pixels during a predetermined frame period in order to display an image corresponding to the image data; A control device for controlling the electro-optical device provided,
A first supply means for supplying a potential corresponding to the changed gradation to the pixel electrode of the first pixel in which the gradation to be displayed changes when rewriting the image displayed on the display unit. When,
Second supply means for supplying the same potential as the potential of the counter electrode to the pixel electrode of the second pixel whose gradation to be displayed does not change when the image is rewritten;
Extracting means for extracting a contour image from the difference between the image before image rewriting and the image after image rewriting;
A determination unit that determines whether or not the potential supply by the first supply unit is performed on a pixel-by-pixel basis for a contour display pixel that displays the contour image;
A contour erasing unit that supplies a potential for erasing the contour image to the pixel electrode of the pixel that is determined not to be supplied with the potential by the first supply unit among the contour display pixels. A control device for an electro-optical device. Number-of-times storage means for storing the number of times that the first supply means should perform the potential supply for each of the plurality of pixels;
The control device for an electro-optical device according to claim 6, further comprising: a decrement unit that decrements the number of times to perform the potential supply stored in the number-of-times storage unit each time the potential supply is performed.   2. A plurality of flag storage means for storing flag information indicating whether or not the potential supply by the first supply means should be performed for each of the plurality of pixels in units of frame periods. The control device for the electro-optical device according to claim 6.   An electro-optical device comprising the control device for an electro-optical device according to claim 6.   An electronic apparatus comprising the electro-optical device according to claim 9.

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