JP2013171237A - Control device of electro-optic device, control method of electro-optic device, electro-optic device, and electronic apparatus - Google Patents

Abstract

When a gradation change operation is newly started in the middle of a gradation change of a pixel, the change in the gradation can be recognized.
If the content of a buffer A (i, j) becomes a content that makes a pixel white during a writing operation that makes a pixel black, three frames including a frame that starts the writing operation that makes the pixel black During this period, the black writing operation is continued, and after the third frame is completed, the writing operation for setting the pixel to white is started. In addition, when the content of the buffer A (i, j) becomes the content of setting the pixel to black during the writing operation for setting the pixel to white, during the three frames including the frame in which the writing operation for setting the pixel to white is started. Continues the white writing operation and starts the writing operation to set the pixel to black after the third frame is completed.
[Selection] Figure 11

Description

  The present invention relates to an electro-optical device control device, an electro-optical device control method, an electro-optical device, and an electronic apparatus.

  As a display device that displays an image, there is an electrophoretic display device using microcapsules. In this display device, an active matrix type is provided with a drive circuit for driving a microcapsule at each of intersections of a plurality of row electrodes extending in the row direction and a plurality of column electrodes extending in the column direction. When a voltage is applied to the row electrode and the column electrode, a potential difference is generated between the electrode provided in the drive circuit and the electrode facing the electrode with the microcapsule interposed therebetween. When a potential difference is generated between electrodes facing each other with the microcapsule interposed therebetween, white particles and black particles in the microcapsule move according to the electric field generated by the potential difference. When the distribution of white particles and black particles in each microcapsule changes, the optical reflection characteristics change and an image is displayed.

Some electrophoretic display devices rewrite an image over a plurality of frames when the display is changed by the active matrix method. However, if rewriting is started on the entire screen when rewriting images over multiple frames, new writing cannot be performed until the writing is completed. Since the next writing is started after the image writing is completed, there is a problem in terms of operability because it takes time.
In order to solve such a problem, a method of performing writing by performing pipeline processing in units of partial areas has been devised (see Patent Document 1). According to the method disclosed in Patent Document 1, when writing an image in two partial areas that do not overlap each other on the screen at different timings, even if the writing of the partial area that has started writing has not been completed. The writing of the partial area where writing is started later can be started, and the display speed is improved as compared with the case where this method is not adopted.

JP 2009-251615 A

By the way, in the case of the method disclosed in Patent Document 1, if the partial areas overlap with each other in part, eventually the partial area where writing was started first is written for the partial area where writing is started later. Writing must be waited until the process is completed, and it takes time to complete the display.
A method of shortening the time until the display is completed by starting the next writing before the writing is completed can be considered, but if the next writing is started immediately after the writing started first, the next writing is started. The next writing is started in a state where the key change is not sufficient. For example, in the case of a display that moves the cursor, if you focus on a certain display position, it will be an operation of deleting the display at that position after displaying the cursor, but if you delete the cursor immediately after starting the cursor display, The gradation does not change until it can be recognized, and the movement path of the cursor is difficult to see.

  The present invention has been made in view of the above-described circumstances, and one of its purposes is to recognize a change in gradation when a gradation change operation is newly started during the gradation change of a pixel. Is to do so.

To achieve the above object, a control device for an electro-optical device according to the present invention includes a display unit including a plurality of pixels, and a writing operation for changing the pixels from a first gradation to a second gradation; A control device of an electro-optical device, wherein a writing operation for changing from a second gradation to the first gradation is performed by an operation of applying a voltage to the pixel a plurality of times, and the gradation of the pixel is changed to the first floor. A counting unit that counts the number of frames that have elapsed since the start of the writing operation for changing to the second gradation or the second gradation, and the counting unit for the pixel when the writing operation is not completed in the pixel Until the number of frames counted in (1) reaches a predetermined number of frames, it is prohibited to start a writing operation for a gradation different from the gradation obtained by the writing operation for the pixel. And, after the number of frames predetermined is counted, and a write unit for starting a write operation to the gradation different gradation obtained by the write operation.
According to the present invention, a new writing operation for changing to a gradation different from the gradation obtained by the writing operation until the predetermined number of frames is counted after the writing operation for changing the gradation is started. Therefore, even if the gradation changing operation is newly started in the middle of the pixel gradation change, the gradation change can be recognized.

In the control device, the writing unit counts the counting unit when the incomplete writing operation is a writing operation from the state of the first gradation or the state of the second gradation of the pixel. Until the determined number of frames reaches a predetermined number of frames, the pixel is prohibited from starting a writing operation to a gradation different from the gradation obtained by the writing operation, and the predetermined number of frames is counted. After that, the writing operation to a gradation different from the gradation obtained by the writing operation may be started.
According to this configuration, the writing operation is performed until the predetermined number of frames is counted after the pixel gradation change writing operation is started from the state of the first gradation or the second gradation. Since a new writing operation for changing to a gradation different from the gradation to be generated is not started, even if a gradation changing operation is newly started in the middle of a pixel gradation change, the gradation change can be recognized. .

In the control device, the writing unit may perform an incomplete writing operation when the pixel is a writing operation from a gradation state between the first gradation and the second gradation. Until the number of frames counted by the counting unit reaches a predetermined number of frames, the pixel operation is prohibited from starting a writing operation to a gradation different from the gradation obtained by the writing operation. After the number of frames is counted, a writing operation to a gradation different from the gradation obtained by the writing operation may be started.
According to this configuration, until the predetermined number of frames is counted after the writing operation for changing the gradation of the pixel is started, a new writing operation for changing to a gradation different from the gradation obtained by the writing operation is performed. Therefore, even if a new gradation change writing operation is started in the middle of the pixel gradation change, the gradation change can be recognized.

Further, in the control device, the predetermined number of frames includes a writing operation for changing the gradation of the pixel to the first gradation and a writing operation for changing the gradation of the pixel to the second gradation. Different configurations may be used.
According to this configuration, the number of times of voltage application in the write operation differs between when the gradation is changed from the first gradation to the second gradation and when the gradation is changed from the second gradation to the first gradation. However, until the number of frames corresponding to each gradation is counted, a new writing operation for changing to a gradation different from the gradation obtained by the writing operation is not started. Even if a new gradation changing operation is started, the gradation change can be recognized.

In order to achieve the above object, a control method for an electro-optical device according to the present invention includes a display unit including a plurality of pixels, and a writing operation for changing the pixels from a first gradation to a second gradation; A control method for controlling an electro-optical device in which a writing operation for changing from a second gradation to the first gradation is performed by an operation of applying a voltage to the pixel a plurality of times, wherein the gradation of the pixel is changed to the first gradation. A counting step that counts the number of frames that have elapsed since the start of the writing operation for changing to one gradation or the second gradation, and if the writing operation is not completed in the pixel, the pixel Until the number of frames counted in the counting step reaches a predetermined number of frames, a gradation different from the gradation obtained by the writing operation is obtained for the pixel. It prohibits the start of operation write attempts, after the number of frames previously determined is counted, and a write step of initiating a write operation to the gradation different gradation obtained by the write operation.
According to the present invention, since the writing operation for changing to the next gradation is not started until the predetermined number of frames is counted after the writing operation for changing the gradation is started, the gradation of the pixel is changed. Even if a new gradation change writing operation is started in the middle of this, the change in gradation can be recognized.

In order to achieve the above object, an electro-optical device according to an aspect of the invention includes a display unit including a plurality of pixels, a writing operation for changing the pixels from a first gradation to a second gradation, and the second floor. An electro-optical device in which a writing operation for changing from a tone to the first gradation is performed by an operation of applying a voltage to the pixel a plurality of times, and the gradation of the pixel is changed to the first gradation or the second floor. A counting unit that counts the number of frames that have elapsed since the start of the writing operation to be changed to each key, and the number of frames counted by the counting unit for the pixel when the writing operation is not completed in the pixel Until the number of frames reaches a predetermined number of frames, the pixel is prohibited from starting a writing operation to a gradation different from the gradation obtained by the writing operation. After the number of frames is counted, and a write unit for starting a write operation to the gradation different gradation obtained by the write operation.
According to the present invention, since the writing operation for changing to the next gradation is not started until the predetermined number of frames is counted after the writing operation for changing the gradation is started, the gradation of the pixel is changed. Even if a new gradation change writing operation is started in the middle of this, the change in gradation can be recognized.

  The present invention can be conceptualized not only as an electro-optical device but also as an electronic apparatus having the electro-optical device.

FIG. 3 is a diagram illustrating a hardware configuration of the display device 1000 and the electro-optical device 1 according to the first embodiment. The figure which showed the cross section of the display area. FIG. 6 is a diagram showing an equivalent circuit of the pixel 110. The figure for demonstrating the structure of a storage area. The block diagram which showed the structure of the function implement | achieved by the controller 5. FIG. The figure for demonstrating the gradation change of a pixel. The flowchart which showed the flow of the process which the controller 5 of 1st Embodiment performs. The flowchart which showed the flow of the process which the controller 5 of 1st Embodiment performs. The flowchart which showed the flow of the process which the controller 5 of 1st Embodiment performs. The flowchart which showed the flow of the process which the controller 5 of 1st Embodiment performs. The figure for demonstrating operation | movement of 1st Embodiment. The figure for demonstrating operation | movement of 1st Embodiment. The figure which showed the structure of RAM4 of 2nd Embodiment. The figure for demonstrating the structure of the 2nd counter storage area C. FIG. The flowchart which showed the flow of the process which the controller 5 of 2nd Embodiment performs. The flowchart which showed the flow of the process which the controller 5 of 2nd Embodiment performs. The figure for demonstrating operation | movement of 2nd Embodiment. The figure for demonstrating operation | movement of 2nd Embodiment. The external view of the electronic book reader 2000. FIG.

[First Embodiment]
(Configuration of the first embodiment)
FIG. 1 is a block diagram showing a hardware configuration of a display apparatus 1000 according to an embodiment of the present invention. The display device 1000 is a device that displays an image, and includes an electrophoretic electro-optical device 1, a control unit 2, a VRAM (Video Random Access Memory) 3, and a RAM 4 that is an example of a storage unit. The electro-optical device 1 includes a display unit 10 and a controller 5.

The control unit 2 is a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM, and the like, and controls each unit of the display device 1000. The control unit 2 accesses the VRAM 3 and writes image data indicating an image to be displayed in the display area 100 to the VRAM 3.
The controller 5 supplies various signals for displaying an image on the display area 100 of the display unit 10 to the scanning line driving circuit 130 and the data line driving circuit 140 of the display unit 10. The controller 5 corresponds to the control device of the electro-optical device 1. Note that the combined portion of the control unit 2 and the controller 5 can be defined as the control device of the electro-optical device 1. Alternatively, the entire control unit 2, controller 5, VRAM 3, and RAM 4 can be defined as a control device for the electro-optical device 1.

The VRAM 3 is a memory that stores image data written by the control unit 2. The VRAM 3 has a storage area (buffer) for each pixel 110 arranged in m rows × n columns to be described later. The image data includes pixel data representing the gradation of each pixel 110, and the pixel data representing the gradation of one pixel 110 is stored in one storage area corresponding to the pixel 110 in the VRAM 3. Pixel data written in the VRAM 3 is read by the controller 5.
The RAM 4 stores various data used for displaying an image on the display area 100. The RAM 4 is provided with a counter storage area B and a scheduled image storage area E. Details of each storage area provided in the RAM 4 will be described later.

  In the display region 100, a plurality of scanning lines 112 are provided along the row (X) direction in the figure, and the plurality of data lines 114 are electrically connected to each scanning line 112 along the column (Y) direction. It is provided to keep insulation. Pixels 110 are provided corresponding to the intersections of the scanning lines 112 and the data lines 114, respectively. For convenience, when the number of rows of the scanning lines 112 is “m” and the number of columns of the data lines 114 is “n”, the pixels 110 are arranged in a matrix with m rows × n columns. Will be configured.

FIG. 2 is a view showing a cross section of the display region 100. As shown in FIG. 2, the display area 100 is roughly configured by a first substrate 101, an electrophoretic layer 102, and a second substrate 103. The first substrate 101 is a substrate in which a circuit layer is formed on an insulating and flexible substrate 101a. The substrate 101a is made of polycarbonate in this embodiment. Note that the substrate 101a is not limited to polycarbonate, and a resin material having lightness, flexibility, elasticity, and insulation can be used. In addition, the substrate 101a may be formed of non-flexible glass. An adhesive layer 101b is provided on the surface of the substrate 101a, and a circuit layer 101c is laminated on the surface of the adhesive layer 101b.
The circuit layer 101c has a plurality of scanning lines 112 arranged in the row direction and a plurality of data lines 114 arranged in the column direction. The circuit layer 101c has pixel electrodes 101d corresponding to the intersections of the scanning lines 112 and the data lines 114, respectively.

  The electrophoretic layer 102 includes a binder 102b and a plurality of microcapsules 102a fixed by the binder 102b, and is formed on the pixel electrode 101d. Note that an adhesive layer formed using an adhesive may be provided between the microcapsule 102a and the pixel electrode 101d.

  The binder 102b is not particularly limited as long as it has good affinity with the microcapsule 102a, excellent adhesion to the electrode, and has insulating properties. A dispersion medium and electrophoretic particles are stored in the microcapsule 102a. As a material constituting the microcapsule 102a, it is preferable to use a flexible material such as a gum arabic / gelatin compound or a urethane compound.

  Dispersion media include water, alcohol solvents (methanol, ethanol, isopropanol, butanol, octanol, methyl cellosolve, etc.), esters (ethyl acetate, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) , Aliphatic hydrocarbons (pentane, hexane, octane, etc.), alicyclic hydrocarbons (cyclohexane, methylcyclohexane, etc.), aromatic hydrocarbons (benzene, toluene, benzenes with long chain alkyl groups (xylene) Hexylbenzene, hebutylbenzene, octylbenzene, nonylbenzene, decylbenzene, undecylbenzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene)), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride) 1,2-dichloroethane, etc.), it can be any of such carboxylates, and the dispersion medium may be other oils. These substances can be used alone or in combination as a dispersion medium, and a surfactant or the like may be further blended to form a dispersion medium.

  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 102a. The black electrophoretic particles are particles made of a black pigment such as aniline black or carbon black, and are positively charged in this embodiment. The white electrophoretic particles are particles made of a white pigment such as titanium dioxide or aluminum oxide, and are negatively charged in this embodiment.

  The second substrate 103 includes a film 103a and a transparent common electrode layer 103b (second electrode) formed on the lower surface of the film 103a. The film 103a plays a role of sealing and protecting the electrophoretic layer 102, and is, for example, a polyethylene terephthalate film. The film 103a is transparent and has an insulating property. The common electrode layer 103b is made of a transparent conductive film such as an indium oxide film (ITO film), for example.

FIG. 3 is a diagram showing an equivalent circuit of the pixel 110. In this embodiment, in order to distinguish each scanning line 112, the scanning lines 112 shown in FIG. 1 are called 1, 2, 3,... (M−1), m-th row in order from the top. You may want to Similarly, in order to distinguish the data lines 114, the data lines 114 shown in FIG. 1 are called 1, 2, 3,..., (N−1), nth column in order from the left. There is a case.
FIG. 3 shows an equivalent circuit of the pixel 110 corresponding to the intersection of the scanning line 112 in the i-th row and the data line 114 in the j-th column. Since the configuration of the pixel 110 corresponding to the intersection of the other data line 114 and the scanning line 112 is the same as the configuration shown in the figure, the data line 114 in the i-th row and the scanning in the j-th column are representatively shown here. The equivalent circuit of the pixel 110 corresponding to the intersection with the line 112 will be described, and the description of the equivalent circuit of the other pixels 110 will be omitted.

  As shown in FIG. 3, each pixel 110 includes an n-channel thin film transistor (hereinafter simply referred to as “TFT”) 110a, a display element 110b, and an auxiliary capacitor 110c. In the pixel 110, the gate electrode of the TFT 110a is connected to the scanning line 112 in the i-th row, the source electrode is connected to the data line 114 in the j-th column, and the drain electrode is a pixel that is one end of the display element 110b. The electrode 101d is connected to one end of the auxiliary capacitor 110c. The auxiliary capacitor 110c has a configuration in which a dielectric layer is sandwiched between a pair of electrodes formed on the circuit layer 101c. The electrode at the other end of the auxiliary capacitor 110c is set to a common voltage across the pixels. The pixel electrode 101d faces the common electrode layer 103b, and the electrophoretic layer 102 including the microcapsules 102a is sandwiched between the pixel electrode 101d and the common electrode layer 103b. Therefore, the display element 110b has a capacity in which the electrophoretic layer 102 is sandwiched between the pixel electrode 101d and the common electrode layer 103b when viewed in an equivalent circuit. The display element 110b holds (stores) the voltage between both electrodes and performs display according to the direction of the electric field generated by the held voltage. In the present embodiment, a common voltage Vcom is applied to the other electrode of the auxiliary capacitor 110c of each pixel 110 and the common electrode layer 103b by an external circuit (not shown).

Returning to FIG. 1, the scanning line driving circuit 130 is connected to each scanning line 112 in the display region 100. The scanning line driving circuit 130 selects the scanning line 112 in the order of 1, 2,..., M-th row under the control of the controller 5, and a high level signal for the selected scanning line 112. , And a low level signal is supplied to the other scanning lines 112 that are not selected.
The data line driving circuit 140 is connected to each data line 114 in the display area, and the data line driving circuit 140 is connected to the data line 114 in each column according to the display content of one row of the pixels 110 connected to the selected scanning line 112. Each supplies a data signal.

In each period (hereinafter referred to as “frame period” or simply “frame”) after the scanning line driving circuit 130 selects the first scanning line 112 until the selection of the m-th scanning line 112 ends. The scanning line 112 is selected once, and a data signal is supplied to each pixel 110 once per frame.
When the scanning line 112 is at a high level, the TFT 110 a whose gate is connected to the scanning line 112 is turned on, and the pixel electrode 101 d is connected to the data line 114. When a data signal is supplied to the data line 114 when the scanning line 112 is at a high level, the data signal is applied to the pixel electrode 101d through the TFT 110a that is turned on. When the scanning line 112 becomes low level, the TFT 110a is turned off. However, the voltage applied to the pixel electrode 101d by the data signal is accumulated in the auxiliary capacitor 110c, and the potential of the pixel electrode 101d and the potential of the common electrode layer 103b. Electrophoretic particles move according to the potential difference (voltage).

  For example, when the voltage of the pixel electrode 101d is + 15V (second voltage) with respect to the voltage Vcom of the common electrode layer 103b, the negatively charged white electrophoretic particles move to the pixel electrode 101d side and become positive The charged black electrophoretic particles move to the common electrode layer 103b side, and the pixel 110 displays black. Further, when the voltage of the pixel electrode 101d is −15 V (first voltage) with respect to the voltage Vcom of the common electrode layer 103b, the positively charged black electrophoretic particles move to the pixel electrode 101d side and are negative. The charged white electrophoretic particles move to the common electrode layer 103b side, and the pixel 110 displays white. Note that the voltage of the pixel electrode 101d is not limited to the voltage described above, and any voltage other than + 15V or −15V described above may be used as long as it is a positive voltage or a negative voltage with respect to the voltage Vcom of the common electrode layer 103b. It may be.

  In the present embodiment, when the display state of each pixel 110 is changed from white (low gradation) as the first gradation to black (high gradation) as the second gradation or from black to white, one frame is used. Instead of supplying the data signal only to the pixel 110 and changing the display state, the display state is changed by a writing operation for supplying the data signal to the pixel 110 over a plurality of frames. This is because when the display state is changed from white to black, even if a potential difference is applied to the electrophoretic particles for one frame, the black electrophoretic particles are not completely moved to the display side. This is because it must not. The same applies to white electrophoretic particles when the display state is changed from black to white. Therefore, for example, when the display state of the pixel 110 is changed from white to black, a data signal for displaying black on the pixel 110 is supplied to the pixel 110 over a plurality of frames, and the display state of the pixel 110 is changed from black to white. In the case of changing to (1), a data signal for displaying white on the pixel is supplied to the pixel 110 over a plurality of frames.

  In this embodiment, the pixel electrode 101d of the pixel 110 in one frame is a positive electrode whose potential is higher than that of the common electrode layer 103b, and the pixel electrode 101d of another pixel 110 in the same frame is the common electrode layer 103b. In contrast, a negative electrode having a lower potential can be obtained. That is, the driving is such that both the positive electrode and the negative electrode can be selected with respect to the common electrode layer 103b within one frame (hereinafter referred to as bipolar driving). More specifically, in one frame, the pixel electrode 101d of the pixel 110 that changes the gradation to the high gradation side (second gradation side) is the positive electrode, and the gradation is on the low gradation side (first gradation side). The pixel electrode 101d of the pixel 110 to be changed is a negative electrode. Note that when the black electrophoretic particles are negatively charged and the white electrophoretic particles are positively charged, the pixel electrode of the pixel 110 that changes the gradation to the high gradation side (second gradation side). 101d may be a negative electrode, and the pixel electrode 101d of the pixel 110 whose gradation is changed to the low gradation side (first gradation side) may be a positive electrode.

Next, each storage area provided in the RAM 4 will be described. FIG. 4 is a diagram showing a part of the pixels 110 in the display area 100 and each storage area corresponding to these pixels 110. Each storage area includes a storage area corresponding to each of the pixels 110 of m rows × n columns.
FIG. 4A shows the arrangement of the pixels 110. Pixel P (i, j) represents one pixel 110 in the i-th row and j-th column. The subscript i represents the row number of the pixel 110 arranged in the matrix, and the subscript j represents the column number.
FIG. 4B shows a buffer corresponding to each of the pixels shown in FIG. 4A in the VRAM 3. For example, the buffer A (i, j) is a storage area corresponding to the pixel P (i, j). The buffer A (i, j) stores pixel data indicating the gradation of the pixel P (i, j). Note that pixel data whose value is “0” is written when the pixel is black, and pixel data whose value is “5” is written when the pixel is white.
FIG. 4C is a diagram showing a storage area corresponding to each of the pixels shown in FIG. 4A in the counter storage area B. For example, the counter storage area B (i, j) is a storage area corresponding to the pixel P (i, j). The counter storage area B (i, j) stores a value indicating the remaining number of application times when a voltage is applied to the pixel P (i, j) a plurality of times.
FIG. 4D is a diagram showing a storage area corresponding to each of the pixels shown in FIG. 4A in the scheduled image storage area E. For example, the scheduled image storage area E (i, j) is a storage area corresponding to the pixel P (i, j). In the scheduled image storage area E (i, j), pixel data of each pixel of an image scheduled to be displayed in the display area 100 is stored.

  Next, the configuration of the controller 5 will be described. FIG. 5 is a block diagram showing functions realized in the controller 5. In the controller 5, a count unit 501 and a writing unit 502 are realized. Each of these blocks may be realized by hardware, or each block may be realized by providing a CPU in the controller 5 and executing a program by this CPU.

The counting unit 501 is a block that counts, for each pixel, the number of frames that have elapsed since the writing operation for changing the pixel gradation to white or black in the writing operation for changing the pixel gradation. The count unit 501 decrements the value of the counter storage area B (i, j) every time one frame period elapses.
Since a predetermined value is stored in the counter storage area B (i, j) at the start of the write operation, and the value of the counter storage area B (i, j) is decremented every time one frame elapses. By referring to the value of the counter storage area B (i, j), the number of frames that have elapsed since the start of the write operation can be specified. That is, it can be said that the count unit 501 counts the number of frames that have elapsed since the start of the write operation by accessing the counter storage area B (i, j).

  The writing unit 502 is a block that performs a writing operation for changing the gradation of a pixel to white or black. The writing unit 502 controls the scanning line driving circuit 130 and the data line driving circuit 140 to apply a voltage for changing the pixel from white to black or a voltage for changing the pixel from black to white to the pixel over a plurality of frames. Thus, the gradation of the pixel is changed to white or black. Note that in the case where the writing operation has not been completed, the writing unit 502 has a gradation different from the gradation obtained by the writing operation until the number of frames counted by the counting unit reaches a predetermined number of frames. After the start of the writing operation is prohibited and a predetermined number of frames are counted, the writing operation to the gradation different from the gradation obtained by the writing operation is started.

In this embodiment, the number of voltage applications (number of frames) when changing the pixel display state from white to black and the number of voltage applications (number of frames) when changing the pixel display state from black to white. Are the same.
In the present embodiment, the gradation of the pixel 110 changes in six stages from 0 to 5, and the pixel data has a higher density as the value is smaller. When the value is 0, black and when the value is 5 Is defined as white. In the present embodiment, when a voltage of −15 V is applied to the pixel electrode 101d five times with respect to the voltage Vcom of the common electrode layer 103b from a state in which the value of pixel data is 0 (a pixel is in a black state), the state shown in FIG. As described above, the gradation of the pixel changes stepwise and the pixel becomes white. On the other hand, when a voltage of +15 V is applied to the pixel electrode 101d five times with respect to the voltage Vcom of the common electrode layer 103b from the state where the pixel data value is 5 (the pixel is in a white state), as shown in FIG. The gradation changes stepwise, and the pixel becomes black.

(First operation example of the first embodiment)
Next, the operation of this embodiment will be described. 7 to 10 are flowcharts showing the flow of processing performed by the controller 5. FIG. 11 is a diagram showing the contents of each storage area that changes over time. Buffer A (1, 1) corresponding to one pixel P (1, 1), counter storage area B (1 , 1) and the contents of the scheduled image storage area E (1, 1). The contents of each storage area are values after the end of the frame period. FIG. 11 also shows the polarity of the voltage applied to the pixel electrode 101d in one frame period with respect to the common electrode layer 103b and the gradation of the pixel P (i, j).

  First, in the first frame of FIG. 11, the value of the pixel data in the buffer A (1, 1) is 5, the value of the counter storage area B (1, 1) is 0, and the scheduled image storage area E (1, 1). The pixel data value of is 5. Here, before the start of the third frame, the voltage applied to the pixel electrode 101d is the same as the voltage Vcom, and the value of each storage area does not change.

  Next, when the contents of the VRAM 3 are rewritten before the start of the third frame, the controller 5 performs the process of FIG. 7 before the start of the frame period. Specifically, the controller 5 rewrites the contents of the counter storage area B and the scheduled image storage area E according to the contents of the buffer and each storage area. First, the controller 5 initializes variable i and variable j to 1 (steps SA1 and SA2). Next, the controller 5 determines whether the value of the buffer A (i, j) is the same as the value of the scheduled image storage area E (i, j). Here, if the value of the buffer A (i, j) and the value of the scheduled image storage area E (i, j) are the same (YES in step SA3), the controller 5 moves the process flow to step SA8.

  On the other hand, when the value of the buffer A (i, j) and the value of the scheduled image storage area E (i, j) are different (NO in step SA3), the controller 5 sets the counter storage area B (i, j) to 0. Judge if there is. When the counter storage area B (i, j) is 0 (YES in step SA4), the controller 5 indicates a value indicating the number of times of application of voltage to the counter storage area B (i, j) (“5 in this embodiment). ") Is written (step SA5). When step SA5 is completed, the controller 5 overwrites the value of the scheduled image storage area E (i, j) with the value of the buffer A (i, j) (step SA6).

  In addition, when the value of the counter storage area B (i, j) is not 0 (NO in step SA4), the controller 5 (counting unit 501) has a value of 3 or more in the counter storage area B (i, j). Judge. That is, since the value of the counter storage area B (i, j) at the start of the write operation is 5, the controller 5 (counting unit 501) determines that the number of frames that have elapsed since the start of the write operation is 2 or less (that is, the counter It can be said that the value of the storage area B (i, j) is 3 or more) or 3 or more (that is, the value of the counter storage area B (i, j) is less than 3). If the value of the counter storage area B (i, j) is less than 3 (NO in step SA7), the controller 5 (writing unit 502) moves the process flow to step SA5. On the other hand, when the value of the counter storage area B (i, j) is 3 or more (YES in step SA7), the controller 5 (writing unit 502) moves the process flow to step SA8.

  The controller 5 determines whether the value of the variable j is n in step SA8. If the value of the variable j is not n, the controller 5 increments the variable j and moves the process flow to step SA3. If the value of the variable j is n, the controller 5 determines whether the value of the variable i is m in step SA9. If the value of the variable i is not m, the controller 5 increments the variable i and moves the process flow to step SA2. Moreover, the controller 5 complete | finishes the process of FIG. 7, when the value of the variable i is m.

  As shown in FIG. 11, when the pixel data in the buffer A (1, 1) is rewritten from 5 to 0 by the control unit 2 before the start of the third frame, at this time, the buffer A (1, 1) Since the value (0) is different from the value (5) in the scheduled image storage area E (1, 1) (NO in step SA3), the controller 5 determines that the value in the counter storage area B (1, 1) is 0. It is judged whether it is. Here, as shown in FIG. 11, when the counter storage area B (1, 1) is 0 (YES in step SA4) before the start of the third frame, the controller 5 determines that the pixel P (1, 1) The number of times of voltage application necessary to change the gray scale level of the signal to 0 (black) is written in the counter storage area B (1, 1) (step SA5). Further, the controller 5 overwrites the contents of the scheduled image storage area E (1, 1) with the contents of the buffer A (1, 1) to zero (step SA6).

  The controller 5 drives the scanning line driving circuit 130 and the data line driving circuit 140 in a frame period after the processing of FIG. 7 is completed (writing step). The controller 5 performs the processes of FIGS. 8 to 10 when driving the data line driving circuit 140. First, the controller 5 initializes variable i and variable j to 1 (steps SB1 and SB2). Next, the controller 5 determines whether or not the value of the scheduled image storage area E (i, j) is zero. If the value of the scheduled image storage area E (i, j) is 0 (black) (YES in step SB3), the controller 5 performs the process shown in FIG. 9 in step SB4.

  First, the controller 5 determines whether the value of the counter storage area B (i, j) is zero. When the value of the counter storage area B (i, j) is not 0 (NO in step SC1), the controller 5 (counting unit 501) decrements the value of the counter storage area B (i, j) (step SC2). . Further, the controller 5 sets the data line 114 in the j-th column to + 15V with respect to the voltage Vcom (step SC3), and moves the process flow to step SB6. If the value of the counter storage area B (i, j) is 0 (YES in step SC1), the controller 5 sets the data line 114 in the jth column to 0 V with respect to the voltage Vcom (step SC4). The flow is moved to step SB6.

  Returning to FIG. 8, when the value of the scheduled image storage area E (i, j) is 5 (white) (NO in step SB3), the controller 5 performs the process of FIG. 10 in step SB5. First, the controller 5 determines whether the value of the counter storage area B (i, j) is zero. When the value of the counter storage area B (i, j) is not 0 (NO in step SD1), the controller 5 (counting unit 501) decrements the value of the counter storage area B (i, j) (step SD2). . Further, the controller 5 sets the data line 114 in the j-th column to −15V with respect to the voltage Vcom (step SD3), and moves the process flow to step SB6. If the value of the counter storage area B (i, j) is 0 (YES in step SD1), the controller 5 sets the data line 114 in the jth column to 0 V with respect to the voltage Vcom (step SD4). The flow is moved to step SB6.

  Returning to FIG. 8, the controller 5 determines whether the value of the variable j is n in step SB6. If the value of the variable j is not n, the controller 5 increments the variable j and moves the process flow to step SB3. Further, when the value of the variable j is n, the controller 5 drives the i-th scanning line (step SB7). Next, the controller 5 determines whether the value of the variable i is m in step SB8. If the value of the variable i is not m, the controller 5 increments the variable i and moves the process flow to step SB2. Moreover, the controller 5 complete | finishes the process of FIG. 8, when the value of the variable i is m.

  In FIG. 11, at the start time of the third frame, the controller 5 has the value of the scheduled image storage area E (1,1) being 0 (YES in step SB3), and the counter storage area B (1,1) Since the value is 5 (NO in step SC1), the value in the counter storage area B (1, 1) is decremented to 4 (step SC2), and the data line 114 in the first column is set to +15 V with respect to the voltage Vcom. (Step SC3). Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electrophoresis is performed. The particles move to the common electrode layer 103b side.

Thereafter, when the contents of the VRAM 3 are rewritten before the start of the fourth frame and the value of the pixel data in the buffer A (1, 1) is set to 5, the controller 5 determines NO in step SA3. Next, since the content of the counter storage area B (1, 1) is 4, the controller 5 (writing unit 502) determines NO in step SA4 and YES in step SA7, and the process flow is step SA8. Move to. That is, here, although the contents of the buffer A (1, 1) and the scheduled image storage area E (1, 1) are different, it is determined that the number of frames that have elapsed since the start of the writing operation is 2 or less, The contents of the image area E (1, 1) are not overwritten with the contents of the buffer A (1, 1).
Thereafter, when the frame period is reached, the controller 5 determines YES in step SB3 because the content of the scheduled image storage area E (1, 1) is 0. Next, since the content of the counter storage area B (1, 1) is 4 at this time, the controller 5 determines NO in step SC1. Then, the value of the counter storage area B (1, 1) is decremented (step SC2), and a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electric The migrating particles move to the common electrode layer 103b side.

Thereafter, the controller 5 performs the same process as the fourth frame in the fifth frame. Next, after the fifth frame is completed, the operation of the controller 5 is as follows.
First, since the value of the buffer A (1, 1) is 5 and the value of the scheduled image storage area E (1, 1) is 0 before the start of the sixth frame, the controller 5 In step SA3, NO is determined. Next, since the content of the counter storage area B (1, 1) is 2, the controller 5 (writing unit 502) determines NO in step SA4 and NO in step SA7, and the process flow proceeds to step SA5. Move. When the controller 5 moves the flow of processing to step SA5, the controller 5 sets the number of times of voltage application (here, 5) necessary to change the gradation of the pixel P (1,1) to 5 (white) in the counter storage area B ( 1, 1) (step SA5). In addition, the controller 5 overwrites the contents of the scheduled image storage area E (1,1) with the contents of the buffer A (1,1) to be 5 (step SA6). That is, in step SA7, since it has been determined that the number of frames that have elapsed since the start of the writing operation is 3 or more, the writing operation for changing the gradation of the pixel P (1,1) to 5 (white) is performed. Be started.

  Thereafter, when the frame period is reached, the controller 5 determines NO in step SB3, and at this time, the value of the counter storage area B (1, 1) is 5 (NO in step SD1). 1, 1) is decremented to 4 (step SD2), and the data line 114 in the first column is set to -15V with respect to the voltage Vcom (step SD3). Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and white electrical The migrating particles move to the common electrode layer 103b side.

  Next, when the content of the VRAM 3 is rewritten before the start of the seventh frame and the value of the pixel data in the buffer A (1, 1) is set to 0, the controller 5 determines NO in step SA3. Next, since the content of the counter storage area B (1, 1) is 4, the controller 5 (writing unit 502) determines NO in step SA4 and YES in step SA7, and the process flow is step SA8. Move to. That is, here, although the contents of the buffer A (1, 1) and the scheduled image storage area E (1, 1) are different, it is determined that the number of frames that have elapsed since the start of the writing operation is 2 or less, The contents of the image area E (1, 1) are not overwritten with the contents of the buffer A (1, 1). Thereafter, when the frame period is reached, the controller 5 determines NO in step SB3 because the content of the scheduled image storage area E (1, 1) is 5. Next, since the content of the counter storage area B (1, 1) is 4 at this time, the controller 5 determines NO in step SD1. Then, the value of the counter storage area B (1, 1) is decremented (step SD2), and a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and first column, and the white The electrophoretic particles move to the common electrode layer 103b side.

Thereafter, the controller 5 performs the same process as the seventh frame in the eighth frame. Next, after the end of the eighth frame, the operation of the controller 5 is as follows.
First, since the value of the buffer A (1, 1) is 0 and the value of the scheduled image storage area E (1, 1) is 5 before the start of the ninth frame, the controller 5 In step SA3, NO is determined. Next, since the content of the counter storage area B (1, 1) is 2, the controller 5 (writing unit 502) determines NO in step SA4 and NO in step SA7, and the process flow proceeds to step SA5. Move. When the controller 5 moves the flow of processing to step SA5, the controller 5 determines the number of voltage applications (here, 5) necessary to change the gradation of the pixel P (1, 1) to 0 (black) in the counter storage area B ( 1, 1) (step SA5). Further, the controller 5 overwrites the contents of the scheduled image storage area E (1, 1) with the contents of the buffer A (1, 1) to zero (step SA6). That is, in step SA7, since it has been determined that the number of frames that have elapsed since the writing operation started is 3 or more, the writing operation for changing the gradation of the pixel P (1,1) to 0 (black) is performed. Be started.

  After that, when the frame period is reached, the controller 5 determines YES in step SB3. At this time, the value of the counter storage area B (1, 1) is 5 (NO in step SC1), so the counter storage area B ( 1, 1) is decremented to 4 (step SC2), and the data line 114 in the first column is set to + 15V with respect to the voltage Vcom (step SC3). Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electrophoresis is performed. The particles move to the common electrode layer 103b side.

  If the contents of the buffer A (1, 1) are not rewritten thereafter, the controller 5 performs the process of step SB4 in the 10th to 13th frames. As a result, a voltage of +15 V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and the black electrophoretic particles move to the common electrode layer 103b side. Since the value of the counter storage area B (1,1) is 0 before the start of the 14th frame, the potential difference between the voltage of the pixel electrode 101d of the pixel in the first row and first column and the voltage Vcom is 0V. Thus, in the pixel in the first row and the first column, the white and black electrophoretic particles do not move.

(Second operation example of the first embodiment)
Next, an operation when the content of the buffer A (1, 1) changes from 0 (black) → 5 (white) → 0 (black) will be described with reference to FIG.
As shown in FIG. 12, when the pixel data of the buffer A (1, 1) is rewritten from 0 to 5 by the control unit 2 before the start of the third frame, at this time, the buffer A (1, 1) Since the value (5) is different from the value (0) in the scheduled image storage area E (1, 1) (NO in step SA3), the controller 5 determines that the value in the counter storage area B (1, 1) is 0. It is judged whether it is. Here, as shown in FIG. 12, if the counter storage area B (1, 1) is 0 (YES in step SA4) before the start of the third frame, the controller 5 determines that the pixel P (1, 1) The number of times of voltage application necessary to change the tone of 5 to 5 (white) is written in the counter storage area B (1, 1) (step SA5). In addition, the controller 5 overwrites the contents of the scheduled image storage area E (1,1) with the contents of the buffer A (1,1) to be 5 (step SA6). Next, when the frame period is reached, at the start of the third frame, the controller 5 has a value of 5 in the scheduled image storage area E (1, 1) (NO in step SB3) and the counter storage area B (1 , 1) is 5 (NO in step SD1), the value of the counter storage area B (1, 1) is decremented to 4 (step SD2), and the data line 114 in the first column is set to the voltage Vcom. On the other hand, it is set to -15V (step SD3). Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and white electrical The migrating particles move to the common electrode layer 103b side.

  Thereafter, when the contents of the VRAM 3 are rewritten before the start of the fourth frame and the value of the pixel data in the buffer A (1, 1) is set to 0, the controller 5 determines NO in step SA3. Next, since the content of the counter storage area B (1, 1) is 4, the controller 5 (writing unit 502) determines NO in step SA4 and YES in step SA7, and the process flow is step SA8. Move to. That is, here, although the contents of the buffer A (1, 1) and the scheduled image storage area E (1, 1) are different, it is determined that the number of frames that have elapsed since the start of the writing operation is 2 or less, The contents of the image area E (1, 1) are not overwritten with the contents of the buffer A (1, 1). Thereafter, when the frame period is reached, the controller 5 determines NO in step SB3 because the content of the scheduled image storage area E (1, 1) is 5. Next, since the content of the counter storage area B (1, 1) is 4 at this time, the controller 5 determines NO in step SD1. Then, the value of the counter storage area B (1, 1) is decremented (step SD2), and a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and first column, and the white The electrophoretic particles move to the common electrode layer 103b side.

  Thereafter, the controller 5 performs the same process as the fourth frame in the fifth frame. Next, after the fifth frame is completed, the operation of the controller 5 is as follows. First, since the value of the buffer A (1, 1) is 0 and the value of the scheduled image storage area E (1, 1) is 5 before the start of the sixth frame, the controller 5 In step SA3, NO is determined. Next, since the content of the counter storage area B (1, 1) is 2, the controller 5 (writing unit 502) determines NO in step SA4 and NO in step SA7, and the process flow proceeds to step SA5. Move. When the controller 5 moves the flow of processing to step SA5, the controller 5 determines the number of voltage applications (here, 5) necessary to change the gradation of the pixel P (1, 1) to 0 (black) in the counter storage area B ( 1, 1) (step SA5). Further, the controller 5 overwrites the contents of the scheduled image storage area E (1, 1) with the contents of the buffer A (1, 1) to zero (step SA6). That is, in step SA7, since it has been determined that the number of frames that have elapsed since the writing operation started is 3 or more, the writing operation for changing the gradation of the pixel P (1,1) to 0 (black) is performed. Be started.

  After that, when the frame period is reached, the controller 5 determines YES in step SB3. At this time, the value of the counter storage area B (1, 1) is 5 (NO in step SC1), so the counter storage area B ( 1, 1) is decremented to 4 (step SC2), and the data line 114 in the first column is set to + 15V with respect to the voltage Vcom (step SC3). Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electrophoresis is performed. The particles move to the common electrode layer 103b side.

  Next, when the contents of the VRAM 3 are rewritten before the start of the seventh frame and the value of the pixel data in the buffer A (1, 1) is set to 5, the controller 5 determines NO in step SA3. Next, since the content of the counter storage area B (1, 1) is 4, the controller 5 (writing unit 502) determines NO in step SA4 and YES in step SA7, and the process flow is step SA8. Move to. That is, here, although the contents of the buffer A (1, 1) and the scheduled image storage area E (1, 1) are different, it is determined that the number of frames that have elapsed since the start of the writing operation is 2 or less, The contents of the image area E (1, 1) are not overwritten with the contents of the buffer A (1, 1). Thereafter, when the frame period is reached, the controller 5 determines YES in step SB3 because the content of the scheduled image storage area E (1, 1) is 0. Next, since the content of the counter storage area B (1, 1) is 4 at this time, the controller 5 determines NO in step SC1. Then, the value of the counter storage area B (1, 1) is decremented (step SC2), and a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electric The migrating particles move to the common electrode layer 103b side.

  Thereafter, the controller 5 performs the same process as the seventh frame in the eighth frame. Next, after the end of the eighth frame, the operation of the controller 5 is as follows. First, since the value of the buffer A (1, 1) is 5 and the value of the scheduled image storage area E (1, 1) is 0 before the start of the ninth frame, the controller 5 In step SA3, NO is determined. Next, since the content of the counter storage area B (1, 1) is 2, the controller 5 (writing unit 502) determines NO in step SA4 and NO in step SA7, and the process flow proceeds to step SA5. Move. When the controller 5 moves the flow of processing to step SA5, the controller 5 sets the number of times of voltage application (here, 5) necessary to change the gradation of the pixel P (1,1) to 5 (white) in the counter storage area B ( 1, 1) (step SA5). In addition, the controller 5 overwrites the contents of the scheduled image storage area E (1,1) with the contents of the buffer A (1,1) to be 5 (step SA6). That is, in step SA7, since it has been determined that the number of frames that have elapsed since the start of the writing operation is 3 or more, the writing operation for changing the gradation of the pixel P (1,1) to 5 (white) is performed. Be started.

  Thereafter, when the frame period is reached, the controller 5 determines NO in step SB3, and at this time, the value of the counter storage area B (1, 1) is 5 (NO in step SD1). 1, 1) is decremented to 4 (step SD2), and the data line 114 in the first column is set to -15V with respect to the voltage Vcom (step SD3). Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and white electrical The migrating particles move to the common electrode layer 103b side.

  If the contents of the buffer A (1, 1) are not rewritten thereafter, the controller 5 performs the process of step SB5 in the 10th to 13th frames. Accordingly, a voltage of −15 V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and the white electrophoretic particles move to the common electrode layer 103b side. Since the value of the counter storage area B (1,1) is 0 before the start of the 14th frame, the potential difference between the voltage of the pixel electrode 101d of the pixel in the first row and first column and the voltage Vcom is 0V. Thus, in the pixel in the first row and the first column, the white and black electrophoretic particles do not move.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The second embodiment of the present invention is different from the first embodiment in that a second counter storage area C is provided as shown in FIG. Further, the configuration of the counting unit 501 and the writing unit 502 and the flow of processing performed by the controller 5 are different from those in the first embodiment. Since other configurations are the same as those of the first embodiment, differences will be described below.

  FIG. 14 is a diagram showing a storage area corresponding to each of the pixels shown in FIG. 4A in the second counter storage area C. For example, the first counter storage area C (i, j) is a storage area corresponding to the pixel P (i, j). In the second counter storage area C (i, j), a value indicating the number of frames until the scheduled image storage area E (i, j) becomes rewritable is stored.

Next, the count unit 501 according to the present embodiment uses the second counter storage area C to calculate the number of frames that have elapsed since the start of the write operation for changing the gradation of the pixel to the first gradation or the second gradation. Use to count.
The count unit 501 decrements the value of the second counter storage area C (i, j) every time one frame period elapses. At the start of the write operation, a predetermined value is stored in the second counter storage area C (i, j), and the value of the second counter storage area C (i, j) is changed every time one frame elapses. Since the value is decremented, the number of frames that have elapsed since the start of the write operation can be specified by referring to the value of the second counter storage area C (i, j). That is, it can be said that the count unit 501 counts the number of frames that have elapsed since the start of the write operation by accessing the second counter storage area C (i, j).

  In addition, when the writing operation is not completed, the writing unit 502 according to the present embodiment until the number of frames counted using the second counter storage area C (i, j) reaches a predetermined number of frames. The pixel prohibits the start of the writing operation to the gradation different from the gradation obtained by the writing operation for the pixel, and after the predetermined number of frames are counted, the gradation different from the gradation obtained by the writing operation The write operation to is started.

  Next, the processing flow of this embodiment will be described. 15 to 16 are flowcharts showing the flow of processing performed by the controller 5. FIG. 17 is a diagram showing the contents of each storage area that changes over time. Buffer A (1, 1) corresponding to one pixel P (1, 1), counter storage area B (1) , 1), the contents of the second counter storage area C (1, 1), and the scheduled image storage area E (1, 1). The contents of each storage area are values after the end of the frame period. Note that FIG. 17 also shows the polarity of the voltage applied to the pixel electrode 101d in one frame period with respect to the common electrode layer 103b and the gradation of the pixel P (1, 1).

  In the second embodiment, as shown in FIG. 15, the process of rewriting the contents of the VRAM is different from the process of FIG. Specifically, if NO is determined in step SA3, it is determined whether the value of the second counter storage area C (i, j) is zero. If the value of the second counter storage area C (i, j) is not 0 (NO in step SA10), the flow of processing moves to step SA6. On the other hand, when the value of the second counter storage area C (i, j) is 0 (YES in step SA10), the same processing of step SA5 and step SA6 as in the first embodiment is performed, and the second counter storage area C ( A value (here, 3) indicating the number of frames until the scheduled image storage area E (i, j) becomes rewritable is stored in i, j) (step SA11).

  Further, in the second embodiment, as shown in FIG. 16, the processing in the frame period is different from the processing in FIG. Specifically, after the process of step SB4 or step SB5 is completed, it is determined whether the content of the second counter storage area C (i, j) is zero. Here, when the content of the second counter storage area C (i, j) is 0 (YES in step SB9), the flow of processing is shifted to step SB6. On the other hand, when the content of the second counter storage area C (i, j) is not 0 (NO in step SB9), the content of the second counter storage area C (i, j) is decremented (step SB10).

(First operation example of the second embodiment)
Next, an operation when the content of the buffer A (1, 1) is changed from 5 (white) → 0 (black) → 5 (white) in the second embodiment will be described with reference to FIG. As shown in FIG. 17, when the pixel data of the buffer A (1, 1) is rewritten from 5 to 0 by the control unit 2 before the start of the third frame, at this time, the buffer A (1, 1) Since the value (0) is different from the value (5) in the scheduled image storage area E (1, 1) (NO in step SA3), the controller 5 sets the value in the second counter storage area C (1, 1). Is determined to be 0. Here, as shown in FIG. 17, when the second counter storage area C (1, 1) is 0 (YES in Step SA10) before the start of the third frame, the controller 5 causes the pixel P (1, The number of times of voltage application required to change the gradation of 1) to 0 (black) is written in the counter storage area B (1, 1) (step SA5), and the contents of the scheduled image storage area E (1, 1) are written. It is overwritten with the contents of the buffer A (1, 1) to become 0 (step SA6). Further, the controller 5 stores the number of frames (3 in the present embodiment) until the scheduled image storage area E (1,1) becomes rewritable in the second counter storage area C (1,1) (step SA11). ).

  Next, at the start of the third frame, the controller 5 performs the process of step SB4 (the process of FIG. 9) because the value of the scheduled image storage area E (1, 1) is 0 at the start of the third frame. Do. Next, since the content of the second counter storage area C (1, 1) is 3, the controller 5 determines NO in step SB9 and sets the value of the second counter storage area C (1, 1). Decrement. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electrophoresis is performed. The particles move to the common electrode layer 103b side.

  Thereafter, when the contents of the VRAM 3 are rewritten before the start of the fourth frame and the value of the pixel data in the buffer A (1, 1) is set to 5, the controller 5 determines NO in step SA3. Next, since the content of the second counter storage area C (1,1) is 2, the controller 5 determines NO in step SA10, and moves the process flow to step SA8. That is, here, although the contents of the buffer A (1, 1) and the scheduled image storage area E (1, 1) are different, the number of frames that have elapsed since the start of the write operation is 3 (the second counter is stored in step SA11). Since the value stored in the area C (i, j) has not been reached, the contents of the scheduled image area E (1,1) are not overwritten with the contents of the buffer A (1,1). Thereafter, when the frame period is reached, the controller 5 determines that the content of the scheduled image storage area E (1, 1) is 0, so that YES is determined in step SB3, and the process of step SB4 is performed. Next, since the content of the second counter storage area C (1, 1) is 2, the controller 5 determines NO in step SB9 and sets the value of the second counter storage area C (1, 1). Decrement. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electrophoresis is performed. The particles move to the common electrode layer 103b side.

  Thereafter, the controller 5 performs the same process as the fourth frame in the fifth frame. Next, after the fifth frame is completed, the operation of the controller 5 is as follows. First, since the value of the buffer A (1, 1) is 5 and the value of the scheduled image storage area E (1, 1) is 0 before the start of the sixth frame, the controller 5 In step SA3, NO is determined. Next, since the content of the second counter storage area B (1, 1) is 0, the controller 5 determines YES in step SA10 and sets the gradation of the pixel P (1, 1) to 5 (white). The number of times of voltage application (here, 5) necessary for changing to the counter storage area B (1,1) is written (step SA5), and the contents of the scheduled image storage area E (1,1) are stored in the buffer A (1,1). Overwrite with the contents of 1) to 5 (step SA6). Further, the controller 5 stores the number of frames (3 in the present embodiment) until the scheduled image storage area E (1,1) becomes rewritable in the second counter storage area C (1,1) (step SA11). ). In other words, based on the fact that the content of the second counter storage area B (1, 1) is 0, it is determined in step SA10 that the number of frames that have elapsed since the start of the write operation is 3 or more. A writing operation for changing the gradation of P (1,1) to 5 (white) is started.

  When the frame period comes after this, the controller 5 determines NO in step SB3, and performs the process of step SB5. Next, since the content of the second counter storage area C (1, 1) is 3, the controller 5 determines NO in step SB9 and sets the value of the second counter storage area C (1, 1). Decrement. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and white electrical The migrating particles move to the common electrode layer 103b side.

  Next, when the content of the VRAM 3 is rewritten before the start of the seventh frame and the value of the pixel data in the buffer A (1, 1) is set to 0, the controller 5 determines NO in step SA3. Next, since the content of the second counter storage area C (1,1) is 2, the controller 5 determines NO in step SA10, and moves the process flow to step SA8. That is, here, although the contents of the buffer A (1, 1) and the scheduled image storage area E (1, 1) are different, the number of frames that have elapsed since the start of the write operation is 3 (the second counter is stored in step SA11). Since the value stored in the area C (i, j) has not been reached, the contents of the scheduled image area E (1,1) are not overwritten with the contents of the buffer A (1,1). Thereafter, when the frame period is reached, the controller 5 determines NO in step SB3 because the content of the scheduled image storage area E (1, 1) is 5, and performs the process of step SB5. Next, the controller 5 decrements the value of the second counter storage area C (1, 1) in step SB10 because the content of the second counter storage area C (1, 1) is 2. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and white electrical The migrating particles move to the common electrode layer 103b side.

  Thereafter, the controller 5 performs the same process as the seventh frame in the eighth frame. Next, after the end of the eighth frame, the operation of the controller 5 is as follows. First, since the value of the buffer A (1, 1) is 0 and the value of the scheduled image storage area E (1, 1) is 5 before the start of the ninth frame, the controller 5 In step SA3, NO is determined. Next, since the content of the second counter storage area C (1,1) is 0, the controller 5 determines NO in step SA10 and sets the gradation of the pixel P (1,1) to 0 (black). The number of times of voltage application (here, 5) necessary for changing to the counter storage area B (1,1) is written (step SA5), and the contents of the scheduled image storage area E (1,1) are stored in the buffer A (1,1). Overwrite with the contents of 1) to 0 (step SA6). Further, the controller 5 stores the number of frames (3 in the present embodiment) until the scheduled image storage area E (1,1) becomes rewritable in the second counter storage area C (1,1) (step SA11). ). In other words, based on the fact that the content of the second counter storage area B (1, 1) is 0, it is determined in step SA10 that the number of frames that have elapsed since the start of the write operation is 3 or more. A write operation for changing the gradation of P (1,1) to 0 (black) is started.

  When the frame period comes after this, the controller 5 determines YES in step SB3 and performs the process of step SB4. Next, since the content of the second counter storage area C (1, 1) is 3, the controller 5 determines NO in step SB9 and sets the value of the second counter storage area C (1, 1). Decrement. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electrophoresis is performed. The particles move to the common electrode layer 103b side.

  If the contents of the buffer A (1, 1) are not rewritten thereafter, the controller 5 performs the process of step SB4 in the 10th to 13th frames. As a result, a voltage of +15 V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and the black electrophoretic particles move to the common electrode layer 103b side. Since the value of the counter storage area B (1,1) is 0 before the start of the 14th frame, the potential difference between the voltage of the pixel electrode 101d of the pixel in the first row and first column and the voltage Vcom is 0V. Thus, in the pixel in the first row and the first column, the white and black electrophoretic particles do not move.

(Second operation example of the second embodiment)
Next, an operation when the content of the buffer A (1, 1) is changed from 0 (black) → 5 (white) → 0 (black) in the second embodiment will be described with reference to FIG.
As shown in FIG. 18, when the pixel data of the buffer A (1, 1) is rewritten from 0 to 5 by the control unit 2 before the start of the third frame, at this time, the buffer A (1, 1) Since the value (5) is different from the value (0) in the scheduled image storage area E (1, 1) (NO in step SA3), the controller 5 sets the value in the second counter storage area C (1, 1). Is determined to be 0. Here, as shown in FIG. 18, if the second counter storage area C (1, 1) is 0 (YES in Step SA10) before the start of the third frame, the controller 5 causes the pixel P (1, The number of times of voltage application necessary to change the gradation of 1) to 5 (white) is written in the counter storage area B (1, 1) (step SA5), and the contents of the scheduled image storage area E (1, 1) are written. It is overwritten with the contents of the buffer A (1, 1) to become 5 (step SA6). Further, the controller 5 stores the number of frames (3 in the present embodiment) until the scheduled image storage area E (1,1) becomes rewritable in the second counter storage area C (1,1) (step SA11). ).

  Next, at the start of the third frame, when the frame period is reached, the controller 5 performs the process of step SB5 (the process of FIG. 10) because the value of the scheduled image storage area E (1, 1) is 5. Do. Next, since the content of the second counter storage area C (1, 1) is 3, the controller 5 determines NO in step SB9 and sets the value of the second counter storage area C (1, 1). Decrement. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and white electrical The migrating particles move to the common electrode layer 103b side.

  Thereafter, when the contents of the VRAM 3 are rewritten before the start of the fourth frame and the value of the pixel data in the buffer A (1, 1) is set to 0, the controller 5 determines NO in step SA3. Next, since the content of the second counter storage area C (1,1) is 2, the controller 5 determines NO in step SA10, and moves the process flow to step SA8. That is, here, although the contents of the buffer A (1, 1) and the scheduled image storage area E (1, 1) are different, the number of frames that have elapsed since the start of the write operation is 3 (the second counter is stored in step SA11). Since the value stored in the area C (i, j) has not been reached, the contents of the scheduled image area E (1,1) are not overwritten with the contents of the buffer A (1,1). Thereafter, when the frame period is reached, the controller 5 determines NO in step SB3 because the content of the scheduled image storage area E (1, 1) is 5, and performs the process of step SB5. Next, since the content of the second counter storage area C (1, 1) is 2, the controller 5 determines NO in step SB9 and sets the value of the second counter storage area C (1, 1). Decrement. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and white electrical The migrating particles move to the common electrode layer 103b side.

  Thereafter, the controller 5 performs the same process as the fourth frame in the fifth frame. Next, after the fifth frame is completed, the operation of the controller 5 is as follows. First, since the value of the buffer A (1, 1) is 0 and the value of the scheduled image storage area E (1, 1) is 5 before the start of the sixth frame, the controller 5 In step SA3, NO is determined. Next, since the content of the second counter storage area B (1, 1) is 0, the controller 5 determines YES in step SA10 and sets the gradation of the pixel P (1, 1) to 0 (black). The number of times of voltage application (here, 5) necessary for changing to the counter storage area B (1,1) is written (step SA5), and the contents of the scheduled image storage area E (1,1) are stored in the buffer A (1,1). Overwrite with the contents of 1) to 0 (step SA6). Further, the controller 5 stores the number of frames (3 in the present embodiment) until the scheduled image storage area E (1,1) becomes rewritable in the second counter storage area C (1,1) (step SA11). ). In other words, based on the fact that the content of the second counter storage area B (1, 1) is 0, it is determined in step SA10 that the number of frames that have elapsed since the start of the write operation is 3 or more. A write operation for changing the gradation of P (1,1) to 0 (black) is started.

  When the frame period comes after this, the controller 5 determines YES in step SB3 and performs the process of step SB4. Next, since the content of the second counter storage area C (1, 1) is 3, the controller 5 determines NO in step SB9 and sets the value of the second counter storage area C (1, 1). Decrement. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electrophoresis is performed. The particles move to the common electrode layer 103b side.

  Next, when the contents of the VRAM 3 are rewritten before the start of the seventh frame and the value of the pixel data in the buffer A (1, 1) is set to 5, the controller 5 determines NO in step SA3. Next, since the content of the second counter storage area C (1,1) is 2, the controller 5 determines NO in step SA10, and moves the process flow to step SA8. That is, here, although the contents of the buffer A (1, 1) and the scheduled image storage area E (1, 1) are different, the number of frames that have elapsed since the start of the write operation is 3 (the second counter is stored in step SA11). Since the value stored in the area C (i, j) has not been reached, the contents of the scheduled image area E (1,1) are not overwritten with the contents of the buffer A (1,1). Thereafter, when the frame period is reached, the controller 5 determines that the content of the scheduled image storage area E (1, 1) is 0, so that YES is determined in step SB3, and the process of step SB4 is performed. Next, the controller 5 decrements the value of the second counter storage area C (1, 1) in step SB10 because the content of the second counter storage area C (1, 1) is 2. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of + 15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and black electrophoresis is performed. The particles move to the common electrode layer 103b side.

  Thereafter, the controller 5 performs the same process as the seventh frame in the eighth frame. Next, after the end of the eighth frame, the operation of the controller 5 is as follows. First, since the value of the buffer A (1, 1) is 5 and the value of the scheduled image storage area E (1, 1) is 0 before the start of the ninth frame, the controller 5 In step SA3, NO is determined. Next, since the content of the second counter storage area C (1,1) is 0, the controller 5 determines NO in step SA10 and sets the gradation of the pixel P (1,1) to 5 (white). The number of times of voltage application (here, 5) necessary for changing to the counter storage area B (1,1) is written (step SA5), and the contents of the scheduled image storage area E (1,1) are stored in the buffer A (1,1). Overwrite with the contents of 1) to 5 (step SA6). Further, the controller 5 stores the number of frames (3 in the present embodiment) until the scheduled image storage area E (1,1) becomes rewritable in the second counter storage area C (1,1) (step SA11). ). In other words, based on the fact that the content of the second counter storage area B (1, 1) is 0, it is determined in step SA10 that the number of frames that have elapsed since the start of the write operation is 3 or more. A writing operation for changing the gradation of P (1,1) to 5 (white) is started.

  When the frame period comes after this, the controller 5 determines NO in step SB3, and performs the process of step SB5. Next, since the content of the second counter storage area C (1, 1) is 3, the controller 5 determines NO in step SB9 and sets the value of the second counter storage area C (1, 1). Decrement. Thereafter, when the scanning line 112 in the first row is driven (step SB7), a voltage of −15V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and white electrical The migrating particles move to the common electrode layer 103b side.

  If the contents of the buffer A (1, 1) are not rewritten thereafter, the controller 5 performs the process of step SB5 in the 10th to 13th frames. Accordingly, a voltage of −15 V with respect to the voltage Vcom is applied to the pixel electrode 101d of the pixel in the first row and the first column, and the white electrophoretic particles move to the common electrode layer 103b side. Since the value of the counter storage area B (1,1) is 0 before the start of the 14th frame, the potential difference between the voltage of the pixel electrode 101d of the pixel in the first row and first column and the voltage Vcom is 0V. Thus, in the pixel in the first row and the first column, the white and black electrophoretic particles do not move.

  As described above, in each operation example of the first and second embodiments, the writing operation is performed on the pixel until the number of frames counted by the counting unit 501 reaches a predetermined number of frames (3 frames). The write operation is started after a predetermined number of frames have been counted. Thus, even when a gradation change operation is newly started in the middle of the pixel gradation change, a display that can recognize the gradation change can be obtained.

[Electronics]
Next, an example of an electronic apparatus to which the display device 1000 according to the above-described embodiment is applied will be described. FIG. 19 is a diagram illustrating an appearance of an electronic book reader using the display device 1000 according to the above-described embodiment. The electronic book reader 2000 includes a plate-shaped frame 2001, buttons 9A to 9F, the electro-optical device 1, the control unit 2, the VRAM 3, and the RAM 4 according to the above-described embodiment. In the electronic book reader 2000, the display area 100 is exposed. In the electronic book reader 2000, the contents of the electronic book are displayed in the display area 100, and the pages of the electronic book are turned by operating the buttons 9A to 9F. In addition, examples of the electronic apparatus to which the electro-optical device 1 according to the above-described embodiment can be applied include a watch, electronic paper, an electronic notebook, a calculator, a mobile phone, and the like.

[Modification]
As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, It can implement with another various form. For example, the present invention may be implemented by modifying the above-described embodiment as follows. In addition, you may combine each of embodiment mentioned above and the following modifications.

In the present invention, depending on the material of the electrophoretic particles, for example, the number of times of voltage application from black to white is five, and the number of times of voltage application from white to black is seven. There may be cases where the number of times of voltage application from white to black is different. In this case, in step SA5, the value written in the counter storage area B (i, j) may be varied according to the contents of the buffer A (i, j).
In the above-described embodiment, the value of the scheduled image storage area E (i, j) is not rewritten during a certain number of frames after the contents of the scheduled image storage area E (i, j) are rewritten. However, this period may be different depending on whether the white is changed to black or the black is changed to white.
For example, in the first embodiment, after determining NO in step SA4, if the value of the scheduled image storage area E (i, j) is 0, the value of the counter storage area B (i, j) is less than 3. If there is, the process flow is shifted to step SA5. If the value of the scheduled image storage area E (i, j) is 5, and if the value of the counter storage area B (i, j) is less than 4, the process proceeds to step SA5. You may make it move a flow.
Further, for example, in the second embodiment, in the step SA11, the second counter storage area C (i, j) is stored in the case where the value of the scheduled image storage area E (i, j) is 0 or 5. The values may be different.

  In the above-described embodiment, the electro-optical device having the electrophoretic layer 102 has been described as an example. However, the present invention is not limited to this. The electro-optical device is not limited as long as writing for changing the display state of a pixel from the first display state to the second display state is performed by a writing operation in which a voltage is applied a plurality of times. For example, an electro-optical device using an electronic powder fluid may be used.

DESCRIPTION OF SYMBOLS 1 ... Electro-optical device, 2 ... Control part, 3 ... VRAM, 4 ... RAM, 5 ... Controller, 9A-9F ... Button, 10 ... Display part, 100 ... Display area, 101 ... 1st board | substrate, 101a ... Board | substrate, 101b ... Adhesive layer, 101c ... Circuit layer, 101d ... Pixel electrode, 102 ... Electrophoresis layer, 102a ... Microcapsule, 102b ... Binder, 103 ... Second substrate, 103a ... Film, 103b ... Common electrode layer, 110 ... Pixel, 110a ... TFT, 110b ... Display element, 110c ... Auxiliary capacitor, 112 ... Scanning line, 114 ... Data line, 501 ... Count part, 502 ... Writing part, 2000 ... Electronic book reader, 2001 ... Frame, A (i, j) ... Buffer, B, B (i, j) ... Counter storage area, C, C (i, j) ... Second counter storage area, E, E (i, j) ... Schedule Image storage area

Claims (7)

A display section including a plurality of pixels, and a writing operation for changing the pixel from the first gradation to the second gradation and a writing operation for changing the second gradation from the first gradation to the pixel A control device for an electro-optical device which is performed by an operation of applying a voltage a plurality of times,
A counting unit that counts, for each pixel, the number of frames that have elapsed since the writing operation for changing the gradation of the pixel to the first gradation or the second gradation is started;
When the writing operation has not been completed for the pixel, the gray level obtained by the writing operation for the pixel is different until the number of frames counted by the counting unit for the pixel reaches a predetermined number of frames. An electro-optic comprising: a writing unit that prohibits the start of a writing operation to a gradation and starts a writing operation to a gradation different from the gradation obtained by the writing operation after a predetermined number of frames are counted Control device for the device. In the writing unit, when the writing operation that has not been completed is a writing operation from the state of the first gradation or the state of the second gradation of the pixel, the number of frames counted by the counting unit is determined in advance. Until the predetermined number of frames is reached, the writing operation for the pixel is prohibited from starting the writing operation to a gradation different from the gradation obtained by the writing operation, and the writing operation is performed after the predetermined number of frames is counted. 2. The control device for an electro-optical device according to claim 1, wherein a writing operation to a gradation different from the gradation obtained by the step is started. The writing unit is counted by the counting unit when the writing operation that is not completed is a writing operation from a state where the pixel is between the first gradation and the second gradation. Until the number of frames reaches a predetermined number of frames, the pixel is prohibited from starting a writing operation to a gradation different from the gradation obtained by the writing operation, and after the predetermined number of frames is counted The control device for an electro-optical device according to claim 1, wherein a writing operation to a gradation different from the gradation obtained by the writing operation is started. The predetermined number of frames is different between a writing operation for changing a pixel gradation to the first gradation and a writing operation for changing a pixel gradation to the second gradation. The control device for an electro-optical device according to any one of claims 1 to 3. A display section including a plurality of pixels, and a writing operation for changing the pixel from the first gradation to the second gradation and a writing operation for changing the second gradation from the first gradation to the pixel A control method for controlling an electro-optical device performed by an operation of applying a voltage multiple times,
A counting step of counting, for each pixel, the number of frames that have elapsed since the writing operation for changing the gradation of the pixel to the first gradation or the second gradation is started;
If the writing operation has not been completed for the pixel, the gray level obtained for the pixel by the writing operation is different until the number of frames counted in the counting step for the pixel reaches a predetermined number of frames. An electro-optic comprising: a write step for prohibiting the start of a write operation to a gradation and starting a write operation to a gradation different from the gradation obtained by the write operation after a predetermined number of frames have been counted Control method of the device. A display section including a plurality of pixels, and a writing operation for changing the pixel from the first gradation to the second gradation and a writing operation for changing the second gradation from the first gradation to the pixel An electro-optical device performed by an operation of applying a voltage multiple times,
A counting unit that counts, for each pixel, the number of frames that have elapsed since the writing operation for changing the gradation of the pixel to the first gradation or the second gradation is started;
When the writing operation has not been completed for the pixel, the gray level obtained by the writing operation for the pixel is different until the number of frames counted by the counting unit for the pixel reaches a predetermined number of frames. An electro-optic comprising: a writing unit that prohibits the start of a writing operation to a gradation and starts a writing operation to a gradation different from the gradation obtained by the writing operation after a predetermined number of frames are counted apparatus.   An electronic apparatus comprising the electro-optical device according to claim 6.