JP2015158530A - Control device, display device, control method and program - Google Patents

Abstract

An afterimage is erased using gradation transition common to all pixels while preventing flash. A control device for controlling a memory-type display device having a plurality of pixels satisfies a determination unit for selecting a first pixel group from a plurality of pixel groups obtained by dividing the plurality of pixels, and a refresh start condition. Control means for sequentially selecting another pixel group adjacent to the first pixel group and refreshing each of the plurality of pixel groups in order, the control means for each of the plurality of pixels. On the other hand, it is controlled to apply a drive waveform in which the number of transitions to the first gradation and the number of transitions to the second gradation different from the first gradation are the same. [Selection] Figure 7

Description

  The present invention relates to driving of an electro-optical device, and more particularly to initialization (refresh) of display of a memory display element.

  A memory-type display element such as an electrophoretic element has a characteristic that a display can be maintained without supplying power. However, there is a problem that an afterimage remains on the display unit depending on the driving method. Since the afterimage is not preferable from the viewpoint of display quality, the afterimage is erased. In general, the afterimage is erased by alternately writing a full-screen white image and a full-screen black image. However, according to this afterimage erasing method, there is a problem that the flashing of the screen is noticeable because the entire screen is switched to black and white. On the other hand, Patent Document 1 discloses an afterimage erasing method that switches black and white alternately one column at a time.

JP 2012-194345 A

  According to the technique described in Patent Document 1, although flash can be prevented, there is a problem in that pixels with different gradation transitions are generated (for example, gradation transitions are different between odd-numbered columns and even-numbered columns).

  In contrast, the present invention provides a technique for erasing an afterimage using gradation transition common to all pixels while preventing flash.

The present invention relates to a control device for controlling a memory-type display device having a plurality of pixels, wherein a determining means for selecting a first pixel group from a plurality of pixel groups obtained by dividing the plurality of pixels, and a refresh start condition Is satisfied, a control unit that sequentially selects another pixel group adjacent to the first pixel group and sequentially refreshes each of the plurality of pixel groups, and the control unit includes: Provided is a control device that controls to apply a drive waveform in which the number of times of transition to the first gradation and the number of times of transition to the second gradation different from the first gradation are the same. .
According to this control device, it is possible to erase afterimages using gradation transition common to all pixels while preventing flash.

The plurality of pixels may be arranged along a first direction and a second direction intersecting with the first direction, and may be divided into a plurality of pixel groups in the first direction and the second direction.
According to this control device, the visual effect can be enhanced as compared with the case where the pixel is divided into unit regions only in one direction.

The determining means may determine any one of the four pixel groups among the plurality of pixel groups as the first pixel group.
According to this control device, it is possible to provide a visual effect that is closer to turning the page than when the four corners are not the starting region.

At the end of the refresh, the number of transitions to the first gradation and the number of transitions to the second gradation may be controlled to be equal for all of the plurality of pixels.
According to this control device, pixel burn-in can be suppressed.

The drive waveform in one refresh is different from other regions in a part of the plurality of regions, and when the drive waveforms in the plurality of refreshes are added up, the number of transitions to the first gradation The number of times of transition to the second gradation may be controlled to be equal.
According to this control device, the visual effect can be enhanced as compared with the case where the application time of the positive voltage is equal to the application time of the negative voltage in the drive waveform in one refresh.

  The control device includes a specifying unit that specifies a part of the plurality of pixels, and the determining unit determines the first pixel group from among the some pixels specified by the specifying unit, The control means may write a voltage according to the drive waveform to a part of the pixels specified by the specifying means. According to this control device, in the case of partial rewriting, afterimages can be erased using gradation transitions common to all pixels to be rewritten while preventing flash.

Further, according to the present invention, when a plurality of pixels including a memory display element, a determination unit that selects a first pixel group from a plurality of pixel groups obtained by dividing the plurality of pixels, and a refresh start condition are satisfied, Control means for sequentially selecting another pixel group adjacent from the first pixel group and refreshing each of the plurality of pixel groups in order, and the control means for each of the plurality of pixels, Provided is a display device that controls to apply a drive waveform in which the number of transitions to a first gradation and the number of transitions to a second gradation different from the first gradation are the same.
According to this display device, afterimages can be erased using gradation transition common to all pixels while preventing flash.

The display device may include a detection unit that detects a direction of the display device, and the determination unit may determine the first pixel group according to the direction detected by the detection unit.
According to this display device, it is possible to provide a visual effect closer to turning the page than when the starting region is determined regardless of the orientation.

The display device includes a first storage unit that stores a plurality of drive waveforms having different lengths, a second storage unit that stores an image before rewriting in the plurality of pixels, and an image after rewriting in the plurality of pixels. The plurality of storage units stored in the first storage unit according to at least one of the third storage unit for storing, the image stored in the second storage unit, and the image stored in the third storage unit Selecting means for selecting one drive waveform from the drive waveforms, and the control means may be controlled to apply the one drive waveform selected by the selection means.
According to this display device, it is possible to use a drive waveform selected according to an image before or after rewriting.

Furthermore, the present invention is a method for controlling a memory-type display device having a plurality of pixels, comprising: selecting a first pixel group from a plurality of pixel groups obtained by dividing the plurality of pixels; When a start condition is satisfied, sequentially selecting other neighboring pixel groups from the first pixel group and sequentially refreshing each of the plurality of pixel groups, and for each of the plurality of pixels A driving method is provided in which a driving waveform is applied in which the number of transitions to the first gradation and the number of transitions to the second gradation different from the first gradation are the same.
According to this driving method, afterimages can be erased using gradation transition common to all pixels while preventing flash.

Furthermore, the present invention is a program for controlling a memory-type display device having a plurality of pixels, wherein the control means includes a plurality of pixel groups obtained by dividing the plurality of pixels into a computer having control means. The step of selecting the first pixel group, and the control means, when the refresh start condition is satisfied, sequentially selects another pixel group adjacent to the first pixel group, and selects each of the plurality of pixel groups. The step of refreshing in order, and the control means, for each of the plurality of pixels, the number of transitions to the first gradation and the number of transitions to the second gradation different from the first gradation And a program for controlling to apply a drive waveform that is the same as.
According to this program, the afterimage can be erased using the gradation transition common to all the pixels while preventing the flash.

1 is a diagram showing a configuration of an electronic apparatus 1000 according to an embodiment. 3 is a schematic diagram showing a cross-sectional structure of the electro-optical panel 10. FIG. FIG. 3 is a diagram illustrating a circuit configuration of the electro-optical panel 10. FIG. 6 is a diagram showing an equivalent circuit of the pixel 14. The figure which illustrates a drive waveform table. The figure which illustrates the drive waveform of the refresh process which concerns on related technology. The figure which illustrates screen transition of refresh processing concerning one embodiment. The figure which illustrates the structure of the display controller. 2 is a diagram illustrating a configuration of a display engine 22. FIG. 10 is a flowchart showing the operation of the electronic apparatus 1000. The figure which shows another example of the screen transition of a refresh process. The figure which shows another example of the screen transition of a refresh process. The figure which shows another example of the screen transition of a refresh process. The figure which illustrates the relationship between the direction of the electronic device 1000, and the origin area | region. The figure which illustrates the refresh process concerning the modification 3.

1. Overview FIG. 1 is a diagram illustrating a configuration of an electronic apparatus 1000 according to an embodiment. The electronic device 1000 is a tablet computer, for example. The electronic apparatus 1000 includes the electro-optical device 1 and the host device 3. The electro-optical device 1 is a display device that displays at least one of characters and images. In this example, the electro-optical device 1 includes an electro-optical panel 10 and a display controller 20. The electro-optical panel 10 is an electro-optical element, more specifically, a device using a memory-type display element that can maintain a display without supplying electric power, specifically, an EPD (Electrophoretic Display). The display controller 20 is a control device that controls the electro-optical panel 10.

  The host device 3 includes a CPU 31, a RAM 32, a storage device 33, an input / output IF 34, and a sensor 35. The CPU 31 is a device that controls another hardware configuration of the electronic device 1000. The RAM 32 is a storage device that functions as a work area when the CPU 31 executes a program. The storage device 33 is a non-volatile storage device that stores data and programs. The input / output IF 34 is an interface through which the host device 3 inputs / outputs data or signals with other devices. In this example, the input / output IF 34 supplies a signal to the display controller 20. The sensor 35 measures a predetermined physical state (for example, tilt, acceleration, temperature, humidity, brightness, etc.) and outputs a signal indicating the measurement result. In addition, the electronic device 1000 includes an input device (for example, a touch screen, a keypad, etc.) and a communication device (for example, a wireless communication device) (all not shown).

  FIG. 2 is a schematic diagram illustrating a cross-sectional structure of the electro-optical panel 10. The electro-optical panel 10 includes a first substrate 11, an electrophoretic layer 12, and a second substrate 13. The first substrate 11 and the second substrate 13 are substrates for sandwiching the electrophoretic layer 12.

  The first substrate 11 includes a substrate 111, an adhesive layer 112, and a circuit layer 113. The substrate 111 is made of an insulating material such as glass. In another example, the substrate 111 may be made of a material having flexibility and lightness in addition to insulation, such as polycarbonate. The adhesive layer 112 is a layer that adheres the substrate 111 and the circuit layer 113. The circuit layer 113 is a layer having a circuit for driving the electrophoretic layer 12. The circuit layer 113 has a pixel electrode 114.

  The electrophoretic layer 12 includes microcapsules 121 and a binder 122. The microcapsule 121 is fixed by a binder 122. As the binder 122, a material having good affinity with the microcapsule 121, excellent adhesion with the electrode, and insulating properties is used. The microcapsule 121 is a capsule in which a dispersion medium and electrophoretic particles are stored. The microcapsule 121 is made of a flexible material such as an Arabic gum / gelatin compound or a urethane compound. Note that an adhesive layer formed of an adhesive may be provided between the microcapsule 121 and the pixel electrode 114.

  Electrophoretic particles are particles (polymer or colloid) having the property of moving by an electric field in a dispersion medium. In the present embodiment, white electrophoretic particles and black electrophoretic particles are stored in the microcapsule 121. The black electrophoretic particles are particles containing a black pigment such as aniline black or carbon black, and are positively charged in this embodiment. The white electrophoretic particles are particles containing a white pigment such as titanium dioxide or aluminum oxide, and are negatively charged in this embodiment.

  The second substrate 13 includes a common electrode 131 and a film 132. The film 132 serves to seal and protect the electrophoretic layer 12. The film 132 is formed of a transparent and insulating material such as polyethylene terephthalate. The common electrode 131 is formed of a transparent and conductive material, for example, indium tin oxide (ITO).

  FIG. 3 is a diagram illustrating a circuit configuration of the electro-optical panel 10. The electro-optical panel 10 includes m scanning lines 115, n data lines 116, m × n pixels 14, a scanning line driving circuit 16, and a data line driving circuit 17. A display area 15 is formed by m × n pixels 14. The scanning line driving circuit 16 and the data line driving circuit 17 are controlled by the display controller 20. Each of the scanning line driving circuit 16, the data line driving circuit 17, and the display controller 20 is an integrated circuit mounted on the substrate 111 by COG (Chip On Glass). The scanning line 115 is disposed along the row direction (x direction) and transmits a scanning signal. The scanning signal is a signal for sequentially and exclusively selecting one scanning line 115 from the m scanning lines 115. The data line 116 is arranged along the column direction (y direction) and supplies a data voltage to the pixel 14. The scanning line 115 and the data line 116 are insulated. The pixel 14 is provided corresponding to the intersection of the scanning line 115 and the data line 116. In addition, when it is necessary to distinguish one scanning line 115 from the other among the plurality of scanning lines 115, the scanning lines 115 are referred to as the first row, the second row,. The same applies to the data line 116. In the display area 15, when the pixel 14 in the i-th row and the j-th column is distinguished from the other pixels 14, it is referred to as a pixel (j, i).

  The scanning line driving circuit 16 outputs a scanning signal Y for sequentially and exclusively selecting one scanning line 115 from the m scanning lines 115. The scanning signal Y is, for example, a signal that sequentially becomes H (High) level exclusively. The data line driving circuit 17 outputs a data signal X. The data signal X is a signal for supplying a data voltage for changing the gradation of the pixel. The data line driving circuit 17 outputs a data signal indicating a data voltage corresponding to the pixel in the row selected by the scanning signal. The scanning line driving circuit 16 and the data line driving circuit 17 are controlled by the display controller 20.

  FIG. 4 is a diagram illustrating an equivalent circuit of the pixel 14. The pixel 14 includes a transistor 141, a capacitor 142, and an electrophoretic element 143. The electrophoretic element 143 includes a pixel electrode 114, the electrophoretic layer 12, and a common electrode 131. The transistor 141 is an example of a switching unit that controls writing of data to the pixel electrode 114, and is an n-channel TFT (Thin Film Transistor), for example. The gate, source, and drain of the transistor 141 are connected to the scanning line 115, the data line 116, and the pixel electrode 114, respectively. When an L (Low) level scanning signal (non-selection signal) is input to the gate, the source and drain of the transistor 141 are insulated. When an H-level scanning signal (selection signal) is input to the gate, the source and drain of the transistor 141 are turned on, and a data voltage is written to the pixel electrode 114. In addition, one electrode of the capacitor 142 is connected to the drain of the transistor 141, and the other electrode of the capacitor 142 is connected to the reference potential Vcom through the wiring 117. The capacitor 142 holds a charge corresponding to the data voltage. One pixel electrode 114 is provided for each pixel 14 and faces the common electrode 131. The common electrode 131 is common to all the pixels 14 and is supplied with the potential EPcom through the wiring 118. The electrophoretic layer 12 is sandwiched between the pixel electrode 114 and the common electrode 131. An electrophoretic element 143 is formed by the pixel electrode 114, the electrophoretic layer 12, and the common electrode 131. A voltage corresponding to the potential difference between the pixel electrode 114 and the common electrode 131 is applied to the electrophoretic layer 12. In the microcapsule 121, the electrophoretic particles move according to the voltage applied to the electrophoretic layer 12 to express gradation. When the potential of the pixel electrode 114 is positive (for example, +15 V) with respect to the potential EPcom of the common electrode 131, the negatively charged white electrophoretic particles move to the pixel electrode 114 side and are positively charged. Black electrophoretic particles move to the common electrode 131 side. At this time, when the electro-optical panel 10 is viewed from the second substrate 13 side, the pixels appear black. When the potential of the pixel electrode 114 is negative (for example, −15 V) with respect to the potential EPcom of the common electrode 131, the positively charged black electrophoretic particles move to the pixel electrode 114 side and are negatively charged. The white electrophoretic particles moving to the common electrode 131 side. At this time, the pixel appears white. Hereinafter, the voltage applied to the pixel electrode 114 is expressed using the potential EPcom as a reference.

  In the following description, a unit period from when the scanning line driving circuit 16 selects the first scanning line to when the selection of the mth scanning line is completed is referred to as “frame”. Each scanning line 115 is selected once per frame, and a data signal is supplied to each pixel 14 once per frame.

  Next, an outline of a method for driving the electro-optical panel 10 will be described. In this example, the time length of one frame is shorter than the response time of EPD. The response time of the EPD is the time until the optical state (for example, relative brightness) of the EPD changes from a reference value (for example, 10%) to another reference value (for example, 90%) when a predetermined voltage (for example, + 15V) is applied. Of time. That is, the gradation cannot be changed from the lowest gradation to the highest gradation by applying a voltage for only one frame. Therefore, voltage application is performed over a plurality of frames in order to transition from the current gradation to a desired gradation. The applied voltage in the EPD is any one of a positive voltage (for example, +15 V), a negative voltage (for example, −15 V), and a zero voltage. There are many sequences of combinations (approximately mathematically permutations) of applied voltages in each frame to transition from the current gray level to the desired gray level. It can be said that the voltage application sequence indicates a change with time of the applied voltage. In this sense, this is hereinafter referred to as a “drive waveform”.

  FIG. 5 is a diagram illustrating a drive waveform table. The drive waveform table describes information on applied voltages in a plurality of frames when the display of a pixel is changed from the current gradation to the next gradation. In FIG. 5, “+”, “−”, and “0” indicate a positive voltage, a negative voltage, and a zero voltage, respectively. The drive waveform table shown in FIG. 5 is for the case where all gradation transitions are performed by applying a voltage of 4 frames. The longer of the number of frames required for the transition from the lowest gradation to the highest gradation and the number of frames required for the transition from the highest gradation to the lowest gradation is referred to as “basic frame number”. In the example of FIG. 5, the number of basic frames is four.

  FIG. 5 shows one drive waveform table, but in the embodiment according to the present invention, a plurality of different drive waveform tables are used for driving the electro-optical panel. Each of the plurality of drive waveform tables is designed for different purposes such as increasing the rewriting speed and reducing the afterimage. In the following description, one or a plurality of drive waveform tables may be referred to as a drive waveform group. In the following description, a drive waveform group designed for a certain purpose is referred to as a “mode”. For example, a driving waveform for high-speed rewriting is referred to as a first mode driving waveform, and a low afterimage driving waveform is referred to as a second mode driving waveform.

  Since driving of the electro-optic panel 10 is affected by environmental factors (for example, temperature), there are a plurality of driving waveform tables corresponding to a plurality of environmental factors in each mode. For example, one drive waveform table selected from the plurality of drive waveform tables is used according to the use scene and environmental factors. FIG. 5 shows a drive waveform table corresponding to one environmental factor of one mode selected in this way.

  From the applied voltage information recorded in one drive waveform table selected according to the drive waveform mode and environmental factors, the applied voltage information according to the current gradation, the next gradation, and the frame number is obtained. Used. For example, in FIG. 5, when the current gray level and the next gray level are dark gray (DG) and light gray (LG), and the second frame, a negative voltage is output as the data voltage. That is, in this example, it can be said that the voltage applied in each frame is determined by the five parameters of the drive waveform mode, environmental factor (temperature), current gradation, next gradation, and frame number. In the following, for the sake of simplicity, an example in which a common drive waveform is used regardless of environmental factors will be described.

  EPD has a characteristic that display can be maintained without supplying power, but there is also a problem that an afterimage remains on the display unit. In order to erase the afterimage, refresh (sometimes referred to as reset) is performed.

  FIG. 6 is a diagram illustrating a drive waveform of the refresh process according to the related art. This driving waveform is divided into three periods of the first to fourth frames, the fifth to eighth frames, and the ninth to twelfth frames. In the first to fourth frames, a voltage for white writing (for making the pixel in the highest gradation state) is applied. In the fifth to eighth frames, a voltage for black writing (to make the pixel in the lowest gradation state) is applied. In the ninth to twelfth frames, a voltage for white writing (for making the pixel in the highest gradation state) is applied. In the related art, this driving waveform is applied to all the pixels 14 at the same timing. When this drive waveform is used, there is a problem that the screen blinks (flashes) because the entire screen is switched to black and white. This embodiment addresses this problem. Specifically, the display area 15 is divided into a plurality of pixel groups. A part of the plurality of pixel groups is a start pixel group. First, the refresh process is started for the pixel group as the start pixel group (application of the voltage of the drive waveform of the refresh process is started). Subsequently, during the refresh process in the start pixel group or after the refresh process is completed, the refresh process is started in another unit region while shifting the start timing.

  FIG. 7 is a diagram illustrating screen transition during the refresh process. In this example, the display area 15 is divided into a matrix. Specifically, it is divided into 24 pixel groups of 6 rows and 4 columns. In each pixel group, “C” indicates an image before rewriting (current image), and “N” indicates an image after rewriting (next image). Further, the black and white areas indicate the state where black and white are displayed, respectively. FIG. 7A shows a state before rewriting. Thereafter, the change in gradation for each basic frame number (for example, 4 frames) is shown.

  Here, the pixel group in the i-th row and the j-th column is represented as a pixel group (j, i). The refresh process is performed in units of pixel groups. Hereinafter, a region that is a target of voltage application (rewriting) among a plurality of pixel groups is referred to as a “target region”. In this example, the lower right pixel group (pixel group (4, 6)) in the display area 15 is a start pixel group (also referred to as a primary pixel group). First, the refresh process is started with the start pixel group as a target area. When the number of basic frames elapses from the state of FIG. 7A, the start pixel group is first displayed in white (FIG. 7B).

  Next, the target area is expanded to a pixel group adjacent to the start pixel group (referred to as a secondary pixel group; pixel group (3, 6) and pixel group (4, 5)). When the number of basic frames elapses from the state of FIG. 7B, the primary pixel group is displayed in black and the secondary pixel group is displayed in white (FIG. 7C).

  Next, the target region is a pixel group adjacent to the secondary pixel group (referred to as a tertiary pixel group; pixel group (2, 6), pixel group (3, 5), and pixel group (4, 4)). Expand to. When the number of basic frames elapses from the state of FIG. 7C, the primary pixel group is displayed in white, the secondary pixel group is displayed in black, and the tertiary pixel group is displayed in white (FIG. 7). (D)).

  Next, the target region is a pixel group adjacent to the third pixel group (referred to as a fourth pixel group; pixel group (1, 6), pixel group (2, 5), pixel group (3,4), and The pixel group (4, 3)) is enlarged. When the number of basic frames elapses from the state of FIG. 7D, the next image is displayed in the first pixel group, the second pixel group is displayed in white, the third pixel group is displayed in black, and the fourth order. The pixel group is in white display (FIG. 7E). The primary pixel group is now rewritten.

  Next, the target region is a pixel group adjacent to the fourth pixel group (referred to as a fifth pixel group; pixel group (1, 5), pixel group (2, 4), pixel group (3, 3), and The pixel group (4, 2)) is enlarged. Since the primary pixel group has been rewritten, it is excluded from the target area. When the number of basic frames elapses from the state of FIG. 7E, the next image is displayed in the second pixel group, the third pixel group is displayed in white, the fourth pixel group is displayed in black, and the fifth order. The pixel group is in white display (FIG. 7F). The secondary pixel group is now rewritten.

  Next, the target region is a pixel group adjacent to the fifth pixel group (referred to as a sixth pixel group; pixel group (1, 4), pixel group (2, 3), pixel group (3, 2), and The pixel group (4, 1)) is enlarged. Since the secondary pixel group has been rewritten, it is excluded from the target area. When the number of basic frames elapses from the state of FIG. 7F, the next image is displayed in the third pixel group, the fourth pixel group is displayed in white, the fifth pixel group is displayed in black, and the sixth order. The pixel group is in white display (FIG. 7G). The third pixel group is now rewritten.

  Next, the target region is a pixel group adjacent to the sixth pixel group (referred to as a seventh pixel group; pixel group (1, 3), pixel group (2, 2), and pixel group (3, 1)). Expand to. Since the third pixel group has been rewritten, it is excluded from the target area. When the number of basic frames elapses from the state of FIG. 7G, the next image is displayed in the fourth pixel group, the fifth pixel group is displayed in white, the sixth pixel group is displayed in black, and the seventh order is displayed. The pixel group is in white display (FIG. 7H). The fourth pixel group is now rewritten.

  Next, the target region is expanded to a pixel group adjacent to the seventh pixel group (referred to as an eighth pixel group; pixel group (1, 2) and pixel group (2, 1)). Since the fourth pixel group has been rewritten, it is excluded from the target area. When the number of basic frames elapses from the state of FIG. 7H, the next image is displayed in the fifth pixel group, the sixth pixel group is displayed in white, the seventh pixel group is displayed in black, and the eighth order. The pixel group is in white display (FIG. 7I). The fifth pixel group is now rewritten. Although the change of the screen after the convenience of the paper is not shown, this change is repeated until the rewriting of all the pixels 14 is completed.

  Looking at each pixel group, all of the gradation transitions are in the order of white writing, black writing, and white writing, and for all the pixels 14, transition from gradation C before rewriting to gradation N after rewriting. During the refresh process, the number of times of white writing (number of times of transition to the highest gradation) and the number of times of black writing (number of times of transition to the lowest gradation) are the same in each pixel. The refresh process is preferably DC balanced. The DC balance refers to a value obtained by integrating an applied voltage with a voltage application time in a certain pixel 14. DC balance means that the integral value is zero. In driving in which the positive voltage and the negative voltage are equal, it is preferable that the application time of the positive voltage and the application time of the negative voltage are equal. Here, a state where the potential of the pixel electrode 114 is higher than the potential of the common electrode 131 is referred to as “positive voltage”, and a state where the potential of the pixel electrode 114 is lower than the potential of the common electrode 131 is referred to as “negative voltage”. . The DC balance only needs to be balanced at the end of the refresh process. That is, when transitioning from gradation C before rewriting to gradation N after rewriting, the number of frames to which the voltage of the first polarity is applied and the second polarity opposite to the first polarity in each of the plurality of pixels. If the number of frames to which the same potential difference voltage is applied is the same, for example, a voltage inserted between the frame to which the first polarity voltage is applied and the frame to which the second polarity voltage is applied is applied. The number of frames that are not processed may be different.

2. Configuration FIG. 8 is a diagram illustrating a configuration of the display controller 20. In FIG. 8, in addition to the display controller 20, related hardware is also illustrated. The display controller 20 includes a host I / F 21, a display engine 22, a timing controller 23, a memory I / F 24, a memory controller 25, a VRAM 26, and a VRAM 27.

  The host I / F 21 receives a signal for instructing image rewriting from the host device 3 and instructs the display engine 22 to rewrite an image in accordance with the received signal.

  The display engine 22 generates a signal for driving the electro-optical device 1 according to the image data. Details of the display engine 22 will be described later.

  The timing controller 23 adjusts the timing of a signal output from the display engine 22 and outputs a control signal to the scanning line driving circuit 16 and the data line driving circuit 17.

  The VRAM 26 is a storage device that stores image data indicating the next image, that is, the image after rewriting. The VRAM 27 is a storage device that stores image data indicating a current image, that is, an image before rewriting. The “current image” here is an image before rewriting during rewriting of the image.

  The memory I / F 24 is an interface that mediates access (data read / write) to the VRAM 26 and VRAM 27.

  When the rewriting of the image is completed, the memory controller 25 writes the next image data stored in the VRAM 26 into the VRAM 27 (that is, copies the next image data from the VRAM 26 to the VRAM 27).

  The waveform memory 29 is a storage device that stores a plurality of drive waveform tables, and its control device. When the display engine 22 gives five parameters of drive waveform mode, environmental factor (temperature), current gradation, next gradation, and frame number, the waveform memory 29 stores the applied voltage corresponding to these parameters. Information is output to the display engine 22. The waveform memory 29 may be provided inside the display engine 22 or outside the display controller 20.

  FIG. 9 is a diagram illustrating a configuration of the display engine 22. In FIG. 9, in addition to the display engine 22, related hardware is also illustrated. The display engine 22 includes a data control unit 221 and a pipe 222.

  The pipe 222 has k pipes (sub-processing units). Each of the k pipes independently performs a process related to voltage application to the pixel electrode.

  The data control unit 221 reads image data from the VRAM 26 and VRAM 27 and outputs the read data to the corresponding pipe for each pixel. That is, the data control unit 221 is an example of an acquisition unit that acquires image data.

  A region on the electro-optical panel 10 is allocated to each pipe. The data control unit 221 selects a pipe according to the position of the pixel. Each pipe reads applied voltage information corresponding to a region on the electro-optical panel 10 from the waveform memory 29 and outputs a signal indicating the read applied voltage information to the timing controller 23.

3. Operation FIG. 10 is a flowchart showing the operation of the electronic apparatus 1000. In the electronic device 1000, the CPU 31 executes a program, and the flow of FIG. 18 is started when a predetermined event occurs in the execution of the program.

  In step S100, the CPU 31 of the host apparatus 3 writes image data indicating the rewritten image into the VRAM 26 via the memory I / F 24. In step S101, the CPU 31 instructs the display controller 20 to refresh and rewrite the image. More specifically, the CPU 31 outputs a refresh instruction (refresh instruction) and an image rewrite instruction (update instruction) to the display engine 22 via the host I / F 21. This rewrite instruction includes information for specifying a pixel group (region to be updated) for rewriting an image and information for specifying a drive waveform mode to be used. Hereinafter, an example in which all of the pixels 14 (all of the display area 15) are to be rewritten will be described.

  When receiving the refresh instruction, the display engine 22 determines a region that is a starting point of the refresh (step S102). That is, in this example, the display engine 22 is an example of a determination unit that determines a start pixel group that is a starting point of refresh. The plurality of pixels 14 are divided into a plurality of pixel groups. Each of the plurality of pixel groups includes at least one pixel. The relationship between the pixel 14 and the pixel group is determined in advance (according to the application or by user setting before the refresh operation starts). For example, one pixel group is composed of 256 pixels 14 of 16 rows and 16 columns. Alternatively, the relationship between the pixel 14 and the pixel group may be specified by the host device 3. In addition, the region that becomes the start pixel group among the plurality of pixel groups is determined in advance in the same manner as the relationship between the pixel 14 and the pixel group. For example, it is determined in advance that the pixel group at the lower right corner of the display area (when the operation button is located toward the display area or when the operation icon is displayed below) is the start pixel group. . When only a part of the display area is rewritten, it is the lower right corner of the rewrite area.

  In step S103, the display engine 22 initializes a frame number counter (in this example, the counter is set to 1).

In step S104, the display engine 22 writes data. As already described, voltage application according to the drive waveform of the refresh process is performed by updating the target region while shifting the start timing sequentially from the start pixel group. That is, in this example, the display engine 22 is an example of a control unit that sequentially selects other adjacent pixel groups from the start pixel group and refreshes each of the plurality of pixel groups in order. Hereinafter, the pixel group that is the jth new target region is referred to as a “jth pixel group”. In this example, data is written through the pipe 222. One or more areas satisfying a specific condition among the target areas are grouped, and one pipe 222 is assigned to the group of target areas. This particular condition depends on the design of the pipe 222, for example:
(I) Pixel groups belonging to the j-th pixel group, and (ii) Adjacent pixel groups In the example of FIG. 7, the adjacent pixel groups may not satisfy the condition (i). Assigned to each group. For example, first, a pipe is assigned to the primary pixel group (that is, the start pixel group), and the pipe 222 is assigned to the pixel group belonging to the secondary pixel group when voltage application to the secondary pixel group is started.

  When one frame has elapsed, the display engine 22 increments the counter (step S105). In step S106, the display engine 22 determines whether the counter value satisfies the condition for updating the target area. In this example, a condition is used in which a predetermined time (for example, a time corresponding to the number of basic frames; 4 frames in the example of FIG. 6) has elapsed since the target area was updated last time. When it is determined that the condition is not satisfied (S106: NO), the display engine 22 proceeds to step S104. When it is determined that the condition is satisfied (S106: YES), the display engine 22 proceeds to step S107.

  In step S107, the display engine 22 updates the target area. In this example, the display engine 22 determines that the pixel group adjacent to the jth pixel group is the (j + 1) th pixel group. Note that even in a region adjacent to the j-th pixel group, the pixel group that is already the target region (the (j−1) -th pixel group) is not a (j + 1) -th pixel group. In the example of FIG. 7, since the pixel group at the lower right corner is the start pixel group, the target area moves or expands toward the upper left. Of the target area before the j-th pixel group, the pixel group for which rewriting has been completed is excluded from the target area. For example, in FIG. 7, the rewriting of the pixel group (4, 6) is completed in FIG. 7E, and thereafter, the pixel group (4, 6) is excluded from the target region until the rewriting of all the pixels is completed. Is done. At this time, the pipe 222 assigned to the pixel group (4, 6) is released.

  In step S108, the display engine 22 determines whether the rewriting has been completed for all the pixels 14 to be rewritten from the current image to the next image. If it is determined that there is a pixel 14 that has not yet been rewritten (S108: NO), the display engine 22 moves the process to step S104. When it is determined that rewriting has been completed for all the pixels 14 of the pixel 14 to be rewritten (S108: YES), the display engine 22 ends the process of FIG.

  According to the present embodiment, the pixels 14 to be rewritten are divided into a plurality of pixel groups, and the refresh process is performed by sequentially shifting the start timing from the starting pixel group. As a result, a visual effect can be obtained, and obstructive blinking of the screen like a conventional refresh can be reduced. In particular, as shown in FIG. 7, when any one of the four corner pixel groups of the display area 15 is set as a start pixel group, a visual effect such as turning a page is obtained.

4). Modifications The present invention is not limited to the above-described embodiments, and various modifications can be made. Hereinafter, some modifications will be described. Two or more of the following modifications may be used in combination.

4-1. Modification 1
The start pixel group is not limited to those exemplified in the embodiment. Pixel groups other than the pixel groups at the four corners of the display area 15 may be the start pixel group. Further, the start pixel group is not limited to a single pixel group. Two or more pixel groups may be the start pixel group. In this case, the pixel group serving as the start pixel group is not limited to the adjacent pixel group. Two or more pixel groups that are not adjacent to each other may be the start pixel group.

  FIG. 11 is a diagram illustrating another example of the refresh process. In this example, the four pixel groups at the bottom of the display area 15 are start pixel groups (FIG. 11B). Starting from the start pixel group, the target area moves upward (FIGS. 11C to 11).

  FIG. 12 is a diagram showing still another example of the refresh process. In this example, alternate pixel groups every other pixel group are start pixel groups (FIG. 12B). Starting from the start pixel group, the target region moves to the adjacent pixel group (FIGS. 11C to 11F). In this example, there are only two refresh processing start timings, that is, a plurality of pixel groups always belong to either the primary pixel group or the secondary pixel group, and there is no tertiary pixel group. According to such refresh processing, rewriting of the display area 15 is completed earlier than in the case where the third pixel group exists. However, the presence of the third pixel group (or later) may reduce user discomfort.

  FIG. 13 is a diagram showing still another example of the refresh process. In this example, two pixel groups (pixel group (2, 3) and pixel group (3, 4)) near the center of the display area 15 are start pixel groups (FIG. 13B). Rewriting starts from the start pixel group, and the target area expands vertically and horizontally. Next, the target area moves. Finally, the target area shrinks and eventually disappears (FIGS. 13C to 13I).

4-2. Modification 2
The start pixel group may be dynamically determined according to the state of the electronic device 1000. For example, the start pixel group may be determined according to the orientation of the electronic device 1000. In this case, the sensor 35 detects the direction of the electronic device 1000. The refresh command sent from the host device 3 to the display controller includes information indicating the direction of the electronic device 1000. The display engine 22 uses this information to determine the start pixel group. For example, the display engine 22 determines the lower right pixel group with respect to the direction of the electronic device 1000 as the start pixel group.

  FIG. 14 is a diagram illustrating the relationship between the orientation of the electronic device 1000 and the start pixel group. FIG. 14A shows a start pixel group when the electronic apparatus 1000 is vertically oriented, and FIG. 14B shows an example when the electronic device 1000 is horizontally oriented. In any example, the pixel group at the lower right corner with respect to the direction of the electronic apparatus 1000 is the start pixel group.

4-3. Modification 3
FIG. 15 is a diagram illustrating a refresh process according to the third modification. In the drive waveform of the refresh process, the number of white writes and the number of black writes may not be common to all the pixels 14 in one refresh, and a plurality of refreshes (more specifically, a plurality of consecutive times) It may be designed to be common in total. How many refreshes are added depends on the drive waveform design. The example of FIG. 15 shows an example in which the number of times of white writing and the number of times of black writing of all the pixels 14 are common in two refreshes. In the odd-numbered refresh, rewriting is performed in the order of white, black, and white in the region 1, and rewriting is performed in the order of white, black, white, black, and white in the region 2. In the even-numbered refresh, the area 1 is rewritten in the order of white, black, white, black, and white, and the area 2 is rewritten in the order of white, black, and white. When the odd-numbered times and even-numbered times are added up, the number of times of white writing and the number of times of black writing are common to both.

4-4. Modification 4
The configuration of the display controller 20 is not limited to that illustrated in FIGS. 8 and 9. For example, the display engine 22 may not have a plurality of pipes. The display engine 22 having only a single processing unit (pipe) may perform rewriting according to the driving waveform of the refresh process. The processing in this case is performed as follows, for example. In addition to the VRAM 26 and the VRAM 27, the display controller 20 has a VRAM for writing data according to the driving waveform of the refresh process. When the refresh process is started, the display engine 22 writes data according to the drive waveform of the refresh process in a storage area corresponding to the target area in the VRAM. The display engine 22 copies the data written in the VRAM to the VRAM 26 for the target area. For the pixel group for which the refresh process has been completed, the data of the next image is copied from the VRAM 27.

4-5. Modification 5
The refresh process may be performed by software processing of the host device 3. That is, in this case, the program executed by the CPU 31 (control means) of the host device 3 includes a group of instructions for executing the refresh process. The CPU 31 writes data according to this instruction group into the VRAM 27. In this case, the display controller 20 may not have a function of performing a refresh process.

4-6. Modification 6
The time length from the start of the refresh process in the jth pixel group to the start of the refresh process in the (j + 1) th pixel group is not limited to the time corresponding to the number of basic frames. For example, when the time less than the number of basic frames has elapsed (that is, at the stage where the gradation transition in the j-th pixel group has not been completed), the refresh process for the (j + 1) -th pixel group may be started. Alternatively, after a time longer than the number of basic frames has elapsed (that is, after a certain period of time has elapsed since the completion of gradation transition in the j-th pixel group), the refresh process for the (j + 1) -th pixel group is started. May be.

4-7. Modification 7
The number of drive waveforms for refresh processing corresponding to a specific environmental factor is not limited to one. There may be a plurality of refresh processing drive waveforms corresponding to a specific environmental factor (for example, a specific temperature). The plurality of drive waveforms may have different lengths. In this case, the display engine 22 selects one drive waveform in accordance with at least one of the image before rewriting (image stored in the VRAM 26) and the image after rewriting (image stored in the VRAM 27). May be. For example, when the image before or after rewriting is an image showing a photograph, a longer drive waveform is selected, and when the image before or after rewriting is an image showing only characters, a shorter drive waveform is selected. It may be selected. That is, in this case, the display engine 22 selects one drive waveform from a plurality of drive waveforms stored in the waveform memory 29 according to at least one of the image stored in the VRAM 26 and the image stored in the VRAM 27. Functions as a selection means.

4-8. Other Modifications The refresh start conditions are not limited to those described in the embodiment. The refresh start condition is not limited to the condition that an instruction is issued from the host device 3, and for example, a condition that a predetermined time (frame) has elapsed since the previous refresh may be used.

  The pixels to be subjected to the refresh process may not be all of the plurality of pixels 14 included in the display area 15 but only a part thereof. In this case, the host device 3 provides the display controller 20 with information that specifies the pixel that is the target of the refresh process. That is, the CPU 31 of the host device 3 functions as a specifying unit that specifies a part of the plurality of pixels 14.

  The equivalent circuit of the pixel 14 is not limited to that described in the embodiment. As long as a controlled voltage can be applied between the pixel electrode 114 and the common electrode 131, the switching element and the capacitor may be combined in any way. In addition, this pixel is driven by a bipolar drive in which there is an electrophoretic element 143 having a different polarity of applied voltage in a single frame, or in all electrophoretic elements 143 in a single frame. Any one of the unipolar drives to which the above voltage is applied may be used.

  The structure of the pixel 14 is not limited to that described in the embodiment. For example, the polarity of the charged particles is not limited to that described in the embodiment. The black electrophoretic particles may be negatively charged and the white electrophoretic particles may be positively charged. In this case, the polarity of the voltage applied to the pixel is opposite to that described in the embodiment. The display element is not limited to an electrophoretic display element using microcapsules. Other memory display elements such as a partition type (microcup) electrophoresis system, an electronic powder, a cholesteric liquid crystal, and an electrochromic may be used.

  The electronic device 1000 is not limited to a tablet computer. An electronic book reader, an electronic notebook, a calculator, a POS terminal, a digital still camera, a mobile phone, a display device, or the like may be used.

DESCRIPTION OF SYMBOLS 1 ... Electro-optical apparatus, 3 ... Host apparatus, 10 ... Electro-optical panel, 11 ... 1st board | substrate, 12 ... Electrophoresis layer, 13 ... 2nd board | substrate, 14 ... Pixel, 15 ... Display area, 16 ... Scanning line drive circuit 17 ... Data line drive circuit, 20 ... Display controller, 21 ... Host I / F, 22 ... Display engine, 23 ... Timing controller, 24 ... Memory I / F, 25 ... Memory controller, 26 ... VRAM, 27 ... VRAM, 31 ... CPU, 32 ... RAM, 33 ... storage device, 34 ... input / output IF, 35 ... sensor, 111 ... substrate, 112 ... adhesive layer, 113 ... circuit layer, 114 ... pixel electrode, 115 ... scan line, 116 ... data Wire 121, microcapsule 122, binder 131, common electrode 132, film 141, transistor 142 Capacity, 143 ... electrophoresis element, 1000 ... electronic equipment

Claims (11)

A control device for controlling a memory display device having a plurality of pixels,
Determining means for selecting a first pixel group from a plurality of pixel groups obtained by dividing the plurality of pixels;
Control means for sequentially selecting other adjacent pixel groups from the first pixel group and refreshing each of the plurality of pixel groups in order when a refresh start condition is satisfied,
The control unit applies a driving waveform to each of the plurality of pixels so that the number of transitions to the first gradation and the number of transitions to the second gradation different from the first gradation are the same. Control device to control. The plurality of pixels are arranged along a first direction and a second direction intersecting the first direction, and are divided into a plurality of pixel groups in the first direction and the second direction. The control device according to claim 1. The control device according to claim 2, wherein the determining unit determines any one of four corner pixel groups among the plurality of pixel groups as the first pixel group. 4. The number of transitions to the first gradation and the number of transitions to the second gradation are the same for all of the plurality of pixels at the end of the refresh. 5. The control device according to one item. The drive waveform in one refresh is different from other regions in a part of the plurality of regions,
4. The number of transitions to the first gradation and the number of transitions to the second gradation are equal when the drive waveforms in the refreshing of a plurality of times are added up. 5. The control device described in 1. A specifying unit for specifying a part of the plurality of pixels;
The determining means determines the first pixel group from among a part of pixels specified by the specifying means,
6. The control device according to claim 1, wherein the control unit causes a voltage according to the drive waveform to be written to a part of the pixels specified by the specifying unit. A plurality of pixels including a memory display element;
Determining means for selecting a first pixel group from a plurality of pixel groups obtained by dividing the plurality of pixels;
Control means for sequentially selecting other adjacent pixel groups from the first pixel group and refreshing each of the plurality of pixel groups in order when a refresh start condition is satisfied,
The control unit applies a driving waveform to each of the plurality of pixels so that the number of transitions to the first gradation and the number of transitions to the second gradation different from the first gradation are the same. Display device to control. Having detection means for detecting the orientation of the display device;
The display device according to claim 7, wherein the determining unit determines the first pixel group according to a direction detected by the detecting unit. First storage means for storing a plurality of drive waveforms having different lengths;
Second storage means for storing an image before rewriting in the plurality of pixels;
Third storage means for storing images after rewriting in the plurality of pixels;
One drive waveform from the plurality of drive waveforms stored in the first storage unit according to at least one of the image stored in the second storage unit and the image stored in the third storage unit And a selection means for selecting
The display device according to claim 7, wherein the control unit performs control so as to apply one driving waveform selected by the selection unit. A method for controlling a memory display device having a plurality of pixels, comprising:
Selecting a first pixel group from a plurality of pixel groups obtained by dividing the plurality of pixels;
When a refresh start condition is satisfied, sequentially selecting other adjacent pixel groups from the first pixel group, and sequentially refreshing each of the plurality of pixel groups,
A control method in which a driving waveform in which the number of transitions to the first gradation and the number of transitions to the second gradation different from the first gradation are the same is applied to each of the plurality of pixels. A program for controlling a memory display device having a plurality of pixels,
To a computer having a control means,
The control means selecting a first pixel group from a plurality of pixel groups obtained by dividing the plurality of pixels;
When the control start condition is satisfied, the control unit sequentially selects another pixel group adjacent to the first pixel group, and sequentially refreshes each of the plurality of pixel groups.
The control unit applies a driving waveform to each of the plurality of pixels so that the number of transitions to the first gradation and the number of transitions to the second gradation different from the first gradation are the same. Program to control.

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