JP2004287425A - Driving method of display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a holding characteristic from deterioration caused by the effect of a residual DC when an electrophoretic display device holds a display image. <P>SOLUTION: There is disclosed a driving method of the electrophoretic display device having a dispersion solution containing liquid and a plurality of electrostatic charged floating particles and an electrode group consisting of at least a 1st electrode and a 2nd electrode for forming an electric field in the dispersion solution by applying voltages. When a display image is written and held, the absolute value of the potential difference between the 1st electrode and 2nd electrode is gradually decreased within a fixed period. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for driving a display device having a display memory property.

  With the development of information devices, needs for low power consumption and thin display devices have been increasing, and research and development of display devices meeting these needs have been actively conducted. In particular, wearable PCs, electronic organizers, etc. are often used outdoors because of their applications, and it is desired that they consume less power and save space. For example, display functions and coordinate input processing using thin displays such as liquid crystal displays are required. Have been commercialized that can be directly input by pressing the content displayed on the display with a pen or a finger.

  However, since many liquid crystals do not have a so-called display memory property, it is necessary to continuously apply a voltage to the liquid crystal during a display period. On the other hand, in a liquid crystal having a display memory property, it is difficult to ensure the reliability when used in various environments such as a wearable PC, and it has not been put to practical use.

  As one of the thin and light-weight display systems having a display memory property, Patent Document 1 discloses Harold D.A. An electrophoretic display device is proposed by Lees et al. This type of electrophoretic display device utilizes an electrophoretic phenomenon in which electrophoretic particles move by Coulomb force when an electric field is applied to a dispersion in which electrophoretic particles are dispersed in a dispersion medium. As one of the electrophoretic display devices, two electrodes, at least one of which is transparent, are opposed to each other at a predetermined interval, and a dispersion liquid including a colored insulating liquid and a plurality of charged electrophoretic particles is sealed between the electrodes. There is one of the configuration. When a voltage is applied between the electrodes, the charged electrophoretic particles are attracted to one of the electrodes depending on the direction of the electric field, and the observer can see the color of the insulating liquid or the color of the charged electrophoretic particles. Will be.

  In such an electrophoretic display device, the charged electrophoretic particles attracted to the electrodes maintain their spatial distribution state when the electric field in the dispersion liquid is uniformly reduced to zero, and the spatial distribution state of the charged electrophoretic particles. Can be displayed. That is, this display element has a display memory property. Therefore, a power supply is required only at the time of display rewriting, which is effective for low power consumption.

  Active matrix electrophoretic display devices utilizing display memory properties have been proposed in Patent Documents 2 and 3.

  According to this proposal, a reset voltage is written to each pixel electrode during the reset operation period. Next, in the writing period, a constant voltage is applied to each pixel electrode only during a period corresponding to the gradation value specified by the image data, or during a certain period, by a voltage corresponding to the gradation value specified by the image data. Apply. Thereafter, during a display image holding operation period after the display state has substantially reached the desired gradation level, the electric field received by the electrophoretic particles is reduced to zero, and the spatial distribution state of the electrophoretic particles is fixed. Therefore, the potential difference between the pixel electrode and the common electrode is set to zero.

US Pat. No. 3,612,758 U.S. Patent Publication AA2002021483 US Patent Publication AA2002005832

  However, according to the results of the research conducted by the present inventors, in driving the conventional electro-conduction device, when the potential difference between the pixel electrode and the common electrode is suddenly reduced to zero as a holding operation, the writing voltage is applied to the liquid layer. When an anti-electric field having a polarity opposite to that of the charged electrophoretic particles is generated and the threshold characteristics of the charged electrophoretic particles are insufficient, the anti-field causes the charged electrophoretic particles to move and fail to maintain a desired display state, thereby impairing the display memory property. There is a problem of doing.

  One of the causes is considered to be residual DC. Hereinafter, the residual DC will be described in detail. As shown in the timing chart of FIG. 3, the driving method of the electrophoretic display device uses, for example, a field having a certain time length, a reset operation for controlling image display, a writing operation, and a holding operation. Perform In FIG. 2A, the horizontal axis is the time axis, the vertical axis is the voltage axis, the solid line is an example of the voltage externally applied to a certain pixel of the electrophoretic display device, and the dashed line is the voltage applied to the dispersion. This is the effective voltage actually applied. FIG. 2B shows the optical response at that time. 2A shows a reset operation period, FIG. 2B shows a write period, and FIG. 2C shows a hold operation period. In the electrophoretic display device, regions having different electric time constants exist in the element, and charges are accumulated at an interface between the regions, so that a DC component is generated. Generally, this DC component is called residual DC. When the residual DC accumulates, for example, in the holding operation period of FIG. 2C, even if the applied voltage to the pixel electrode is set to 0 V as indicated by the solid line, the applied voltage is opposite to the applied voltage as indicated by the broken line in the dispersion liquid. A polar anti-electric field may be generated, and some of the charged electrophoretic particles are written back by the action of the anti-electric field, so that the image is not sufficiently held.

  The present invention has been made to solve the above problem, and is a method for driving a display device having at least a first electrode and an electrode group including a second electrode and having a display memory property, After a voltage for writing a display image is applied between the electrode and the second electrode, the absolute value of the potential difference between the first electrode and the second electrode is gradually attenuated for a certain period of the display image holding period. And a method for driving a display device.

  At the time of writing / holding operation of the display image, the residual DC is not abruptly reduced to zero during a certain period of time, but the absolute value of the potential difference between the pixel electrode and the common electrode is reduced. This problem is reduced by minimizing the generation of an anti-electric field.

  By using the driving method disclosed in the present invention, it is possible to prevent the deterioration of the holding due to the influence of the residual DC during the holding operation of the display image of the electrophoretic display device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking an example of application to an electrophoretic display device which is one of display devices having a display memory function. The present invention is not limited to application to an electrophoretic display device, but a display device having another display memory property, for example, a toner display (IEICE EID99-154, P7 (2000), Chiba Univ.), Gyricon (SID '77 Digest, p114, Xerox) and the like. The description will proceed with the first electrode described in the claims as a pixel electrode and the second electrode in the claims as a common electrode.

  In FIG. 1A, the horizontal axis is a time axis, the vertical axis is a voltage axis, a solid line is an example of a voltage externally applied to a certain pixel of the electrophoretic display device, and a dashed line is a voltage applied to the dispersion liquid. This is the effective voltage actually applied. FIG. 1B shows the optical response at that time. 1A shows a reset operation period, FIG. 1B shows a write period, and FIG. 1C shows a hold operation period. The period before the reset operation period (A) may be considered to indicate the display state performed last time. In the reset period (A) after the time t1, the reset voltage Vr is applied to reset the display previously performed. Then, in a writing period (B) after reaching the time t2, the element is driven by applying the writing voltage Vw to display a desired gradation level. The gradation level is controlled by pulse width modulation or amplitude modulation of the write voltage Vw. The gradation level can be controlled by the application time of the write voltage Vw when performing pulse width modulation, and by the magnitude of the write voltage Vw when performing voltage amplitude modulation. Next, in the holding operation period (C) after the time t3, the holding is performed by controlling the potential of the first electrode or the second electrode in order to reduce the electric field acting on the particles to zero. At this time, instead of suddenly setting the potential difference between the first electrode and the second electrode to zero to prevent the residual DC from acting as an anti-electric field, the potential difference between the first electrode and the second electrode is reduced. , The generation of a counter-electric field is suppressed as much as possible, and the holding characteristics are improved. By this holding operation, the optical response is kept constant during the holding operation period (C) in FIG. 1B and thereafter.

  An example of the method of the present invention for gradually attenuating the absolute value of the potential difference between the first electrode and the second electrode within a certain period for suppressing a counter electric field will be described with reference to FIG. . In FIG. 4, the horizontal axis represents the time axis, and the vertical axis represents the absolute value of the potential difference between the first electrode and the second electrode. The damping method may be set so as to suppress the anti-electric field. For example, a logarithmic damping method (FIG. 4A), an exponential damping method (FIG. 4B), a linear damping method ( FIG. 4C).

  Hereinafter, the driving method of the present invention will be described by taking an active matrix method using a TFT as a switching element connected to each pixel of the electrophoretic display device as an example. The drive method of the present invention in which the absolute value of the potential difference of the present invention is gradually attenuated within a certain period is not limited to the active matrix method using a TFT, and the active matrix method using another switching element such as a TFD, or It can be applied to the segment system and simple matrix system.

  Note that the driving method of the present invention can be applied to a vertically moving electrophoretic display device as well as to a horizontally moving electrophoretic display device.

  Further, in the present invention, the charged electrophoretic particles and the dispersion medium may be included in each of a large number of microcapsules.

  Further, the present invention is not limited to the case where the display state substantially reaches a desired gradation level and the writing operation to all the pixels is completed, and then the holding operation of the display image is performed. This is also effective when the holding operation is started before the end, that is, when the desired writing operation is ended during the application of the attenuation waveform.

  Hereinafter, the driving method of the present invention will be described in more detail with reference to the drawings according to embodiments.

(Example 1)
An electrophoretic display device applies an voltage to an electrophoretic display panel in which pixels and switching elements are arranged in a matrix of m rows and n columns, and applies a voltage to scanning lines in m rows and data lines in n columns. Peripheral devices for driving the pixels. In this embodiment, a display device in which m = 10 and n = 20 will be described. Each pixel has a size of 200 μm square.

  FIG. 5 is a block diagram showing an example of the configuration of the electrophoretic display device according to the present invention. It comprises a graphic controller 1, a graphic memory 2, a panel controller 3, a central processing unit (CPU) 4, a power supply unit 5, a power supply control unit 6, a data line drive circuit 7, a scanning line drive circuit 8, and an electrophoretic display panel 9. You.

  The graphic controller 1 inputs the image data of the graphic memory 2 to the panel controller 3 according to the information transfer clock.

  Further, the panel controller 3 generates a control signal such as a field synchronization signal, a horizontal synchronization signal, a data acquisition clock, and the like and display data based on the image data input from the graphic controller 1, and outputs the data line driving circuit 7 and the scanning signal. Transfer to the line drive circuit 8.

  The data line driving circuit 7 and the scanning line driving circuit 8 output a driving voltage to the electrophoretic display panel 9 according to a control signal and display data received from the panel controller 3 to perform display.

  The power supply unit 5 is a part that supplies power to each block, and the power supply control unit 6 controls execution / stop of power supply. The power control unit 6 operates based on a power switch state signal input in response to turning on / off of a power switch of the electrophoretic display device.

  FIG. 6 shows a schematic diagram of one pixel of the electrophoretic display panel 9. A first electrode of the electrophoretic display element 15 is connected to a drain electrode of a thin film transistor (TFT) 13 for active matrix driving display, and a second electrode of the electrophoretic display element 15 is at a voltage Vcom. Connected to common electrode. The second electrodes of all the pixels are connected to the common electrode. The auxiliary capacitance 14 is also connected to the common electrode. The data line 11 is connected to the source electrode of the TFT 13, and the scanning line 12 is connected to the gate electrode of the TFT 13.

  The reset operation will be described in detail with reference to FIG. Consider a case in which a TFT having m rows of scanning lines and n columns of data lines is used to control the potentials of pixel electrodes of m rows and n columns of electrophoretic display elements connected to the TFTs. Here, the pixel at the i-th row and the j-th column is Pij. First, a reset voltage Vr is applied to the data lines in all columns while a gate voltage corresponding to the OFF voltage of the TFT is applied to the scanning lines in all rows, and then the TFTs are turned on to the scanning lines in all rows. A gate voltage corresponding to the voltage is applied. After the spatial distribution state of the charged electrophoretic particles in the dispersion is initialized to a substantially sufficient level, a gate voltage corresponding to the OFF voltage of the TFT is applied to all the scanning lines. The reset operation is completed as described above.

  Next, the write operation will be described in detail with reference to FIGS. 7, 8 and 9. These diagrams are schematic diagrams, and the relationship among the lengths of the writing period, the writing scanning period, the writing operation period, and the holding operation period does not always accurately reflect the magnitude relationship during actual driving. Consider a case in which a TFT having m rows of scanning lines and n columns of data lines is used to control the potentials of pixel electrodes of m rows and n columns of electrophoretic display elements connected to the TFTs. As described above, in this embodiment, m = 10 and n = 20.

  8 and 9, the horizontal axis is the time axis, and the vertical axis is the voltage axis. 8 shows the gate voltage Yi of the i-th row and the signal voltage Vj of the j-th column, and FIG. 9 shows the potential Vij of the pixel electrode when these voltages are applied to the pixel Pij of the i-th row and the j-th column. I have. First, the gate voltage Y1 corresponding to the ON voltage of the TFT is applied only to the first scanning line, and the gate voltage corresponding to the OFF voltage of the TFT is applied to the other scanning lines. Signal voltages V11 to V1n corresponding to a desired gradation level for each pixel are applied to each data line.

  The voltage applied to the gate line is -5 V when OFF (i.e., not selected) and 40 V when ON (i.e., selected). The peak value of the pulse is 45V. The application time of the selection pulse is 20 μs. The signal voltage applied to the data line is changed between 0V and 20V according to the image.

  Next, signal voltages V21 to V2n corresponding to a desired gradation level for each pixel in the second row are applied to each data line while a gate voltage corresponding to the OFF voltage of the TFT is applied to all the scanning lines. Then, a gate voltage Y2 corresponding to the ON voltage of the TFT is applied only to the second scanning line.

  Hereinafter, the same is repeated until the scanning up to the m-th row is completed. Since each scanning line selection time is 20 μs and the number of scanning lines is m = 10, the writing scan period is 200 μs.

  If it takes time after the writing scan is completed to reach the equilibrium position of the migrating particles, writing is not performed for the time. The address operation period immediately after the address scanning period in FIG. 8 represents that period. In the electrophoresis apparatus of this embodiment, this period is 500 ms.

  Next, the holding operation will be described in detail with reference to FIG. 7, FIG. 8, and FIG. During the write operation period, the display state substantially reaches a desired gradation level, and during the holding operation of the display image after the writing to all the pixels is completed, a plurality of frames are used as shown in FIGS. Thus, the absolute value of the potential difference between the first electrode and the second electrode is gradually attenuated. In this embodiment, the absolute value of the potential difference between the first electrode and the second electrode is attenuated using N = 10 frames. Hereinafter, the pixel at the i-th row and the j-th column is defined as Pij.

  In FIG. 8, at the end of the writing period, that is, at the end of the writing scanning period and the subsequent writing operation period, the display state has substantially reached the desired gradation level. Thereafter, during a period until the next writing is performed, that is, a period during which the holding operation is performed, the image is maintained because of the memory property. In this embodiment, an attenuation voltage application period for gradually attenuating the potential of the pixel electrode is provided for a plurality of frames in the display image after the writing operation to all the pixels is completed.

  The application pulse and period of each frame are the same as during the address scanning period, but the signal voltage applied to the data line is made smaller than the voltage during the address scanning period, and the value is gradually reduced with each frame. Go.

  Hereinafter, a more specific description will be given.

  First, the operation in the first frame will be described. A gate voltage corresponding to the ON voltage of the TFT is applied to the first scanning line, and a gate voltage corresponding to the OFF voltage of the TFT is applied to the other scanning lines. A voltage of 90% of the signal voltage value corresponding to each gradation applied to the pixel is applied to each data line. Similarly, while applying ON voltage sequentially to the scanning lines up to m rows and selecting the same, a voltage of 90% of the voltage value applied to each pixel during the address scanning period is applied to each pixel from each data line. I do. Thus, the operation in the first frame is completed.

  In the second frame, a voltage corresponding to 80% of the signal voltage value during the writing scan period is applied to each pixel.

  Hereinafter, the frame operation is similarly repeated. In the ninth frame, a voltage corresponding to 10% of the signal voltage value during the writing scan period is applied to each pixel. In the last tenth frame, 0V is applied to each pixel.

  As described above, the voltage decay rate is determined so that the decay is sufficiently completed by the (N-1) th frame, and the electrode potentials of all the pixels are set to zero in the Nth frame. By performing the operation of applying the attenuation voltage, the residual DC is reduced, and there is no influence of the residual DC voltage in the next writing scan. That is, a desired display state is written without being affected by the previous display.

  The method described above is a method of actively performing attenuation. That is, a voltage is applied to each frame of the active matrix drive, and the applied voltage is gradually attenuated. Therefore, by appropriately setting the voltage for each frame, arbitrary attenuation can be performed.

  According to the method described above, the effect of the residual DC can be reduced during the operation of holding the display image of the electrophoretic display device, and the display characteristics have been improved.

(Example 2)
After the reset operation and the write operation in the first embodiment are completed, the present embodiment in which the holding operation is performed as follows is also conceivable.

  The holding operation will be described in detail with reference to FIGS. 7, 10, and 11. These diagrams are schematic diagrams, and the relationship among the lengths of the writing period, the writing scanning period, the writing operation period, and the holding operation period does not always accurately reflect the magnitude relationship during actual driving. Consider a case in which a TFT having m rows of scanning lines and n columns of data lines is used to control the potentials of pixel electrodes of m rows and n columns of electrophoretic display elements connected to the TFTs. Here, the pixel at the i-th row and the j-th column is Pij.

  FIG. 10 is a diagram showing the gate voltage and the signal voltage. The horizontal axis shows the time axis, and the vertical axis shows the voltage axis. The gate voltage on the i-th row is Yi, and the signal voltage input to the pixel Pij is Vij. FIG. 11 shows the potential of each pixel electrode when a gate voltage and a signal voltage are applied to each pixel at the time of writing and holding operation as shown in FIG.

  The operation in the writing period is the same as in the first embodiment. At the end of the writing period, the display state has substantially reached the desired gradation level.

  In the present embodiment, a current leak is caused in the switching element for a certain period in the holding operation period, thereby gradually attenuating the potential of the pixel electrode.

  Specifically, a leak current flows between the drain and the source of the TFT by applying a certain voltage Vh, which is larger than the OFF voltage and smaller than the ON voltage, to the gate electrode of the TFT for all the scanning lines. Thus, the absolute value of the potential difference between the first electrode and the second electrode is attenuated earlier than according to the time constant when the TFT is OFF and later than according to the time constant when the TFT is ON.

  The gate electrode of each transistor is supplied with a voltage that is lower than the ON voltage, but in the middle of the operation of the transistor close to ON, so that a small amount of current flows and the charge stored in the pixel is released. In this embodiment, the gate ON voltage of the transistor is 40 V, the OFF voltage is -5 V, and Vh is 38 V.

  According to the method described above, as in the first embodiment, the effect of the residual DC can be reduced during the operation of holding the display image of the electrophoretic display device, and the holding characteristics are improved.

(Example 3)
In the holding operation of the second embodiment, when it is desired to complete the holding operation period earlier, for example, when low power consumption is required and the power supply time from the power supply during the holding operation period is to be shortened, two or more desired stages are required. Is set, and the absolute value of the potential difference between the first electrode and the second electrode is attenuated in accordance with the condition. This will be described with reference to FIGS. 7, 12, and 13. These diagrams are schematic diagrams, and the relationship among the lengths of the writing period, the writing scanning period, the writing operation period, and the holding operation period does not always accurately reflect the magnitude relationship during actual driving. Consider a case in which a TFT having m rows of scanning lines and n columns of data lines is used to control the potentials of pixel electrodes of m rows and n columns of electrophoretic display elements connected to the TFTs. Here, the pixel at the i-th row and the j-th column is Pij. FIG. 12 is a diagram showing the gate voltage and the signal voltage. The horizontal axis shows the time axis, and the vertical axis shows the voltage axis. The gate voltage on the i-th row is Yi, and the signal voltage input to the pixel Pij is Vij. FIG. 13 shows the potential of each pixel electrode when a gate voltage and a signal voltage are applied to each pixel as shown in FIG. 12 during writing and holding operation. At the time of the display image holding operation after the display state substantially reaches the desired gradation level and the writing operation to all the pixels is completed, a certain period in the holding operation period is divided into two or more periods. , The potential of the pixel electrode is gradually attenuated. FIG. 12 shows an example in which a certain period in the holding operation period is divided into two periods and attenuation is performed. This will be described more specifically with reference to this example. The holding operation period is divided into two or more periods. Needless to say, it is good. From the state in which the gate voltage corresponding to the OFF voltage of the TFT is applied to all the scanning lines, as shown in FIG. 12, first, in the first period, the gate electrode of the TFT is larger than the OFF voltage and smaller than the ON voltage. By applying a certain voltage Vh1 and applying a certain voltage Vh2 larger than the OFF voltage and smaller than the ON voltage to the gate electrode of the TFT in the next period, as shown in FIG. The absolute value of the potential difference between the first electrode and the second electrode is attenuated in two stages earlier than according to the time constant and later than according to the ON time constant.

  According to the method described above, similarly to the first embodiment, the effect of the residual DC can be reduced during the operation of holding the display image of the electrophoretic display device, and the holding characteristics are improved.

(Example 4)
In the present embodiment, after the operation in the arbitrary I-th frame during the holding operation period is completed in the first embodiment, the state is changed from the state in which the gate voltage corresponding to the OFF voltage of the TFT is applied to all the scanning lines. By applying a certain voltage, which is larger than the OFF voltage and smaller than the ON voltage, to the gate electrodes of the TFTs for all the scanning lines, faster than the time constant when the TFT is OFF, The absolute value of the potential difference between the first electrode and the second electrode is attenuated later than according to the time constant.

  According to the method described above, similarly to the first embodiment, the effect of the residual DC can be reduced during the operation of holding the display image of the electrophoretic display device, and the holding characteristics are improved.

FIG. 4 is a correlation diagram of an externally applied voltage, an effective voltage to a dispersion liquid, and an optical response at each operation in the present invention. FIG. 7 is a correlation diagram of an externally applied voltage, an effective voltage to a dispersion liquid, and an optical response at each operation in a conventional example. 6 is a timing chart showing each operation period. The figure which shows the example of the attenuation method of the absolute value of a potential difference. FIG. 2 is a block diagram of an electrophoretic display device and peripheral circuits thereof. FIG. 3 is a diagram illustrating an electrophoretic display element and a thin film transistor (TFT) per pixel. FIG. 2 is a schematic diagram of an electrophoretic display panel and a driving circuit. FIG. 7 is a diagram illustrating an example of a gate voltage and a signal voltage in a writing period and a holding operation period when an absolute value of a potential difference is attenuated by a plurality of frames. FIG. 9 is a diagram showing the potential of each pixel electrode when the gate voltage and signal voltage shown in FIG. 8 are applied. FIG. 7 is a diagram illustrating an example of a gate voltage and a signal voltage in a writing period and a holding operation period when the absolute value of a potential difference is gradually attenuated. FIG. 11 is a diagram illustrating the potential of each pixel electrode when the gate voltage and the signal voltage illustrated in FIG. 10 are applied. FIG. 7 is a diagram illustrating an example of a gate voltage and a signal voltage in a writing period and a holding operation period when an absolute value of a potential difference is attenuated under two or more attenuation conditions. The figure which shows an example of each pixel electrode electric potential at the time of attenuating an absolute value of an electric potential difference by two or more attenuation conditions.

Explanation of reference numerals

Reference Signs List 1 graphic controller 2 graphic memory 3 panel controller 4 central processing unit (CPU)
Reference Signs List 5 power supply unit 6 power supply control unit 7 data line drive circuit 8 scan line drive circuit 9 electrophoretic display panel 10 pixel 11 data line 12 scan line 13 thin film transistor (TFT)
14 Auxiliary capacitance 15 Electrophoretic display element per pixel

Claims (7)

A method for driving a display device including at least a first electrode and an electrode group including a second electrode, and having a display memory property,
After a voltage for writing a display image is applied between the first electrode and the second electrode, the absolute value of the potential difference between the first electrode and the second electrode is determined for a certain period of the display image holding period. A method for driving a display device, wherein the display device is gradually attenuated.   2. The display device according to claim 1, wherein when the display device is driven in an active matrix, an absolute value of a potential difference between the first electrode and the second electrode is gradually attenuated according to a desired setting condition. Drive method.   2. The driving device according to claim 1, wherein when the display device is driven in an active matrix, an absolute value of a potential difference between the first electrode and the second electrode is actively attenuated over a plurality of frames. Method.   When a thin film transistor (hereinafter, referred to as a TFT) is used as a switching element connected to each pixel of the display device and the display device is driven in an active matrix, the signal voltage of the TFT is set for each frame. The method according to claim 3, wherein the absolute value of the potential difference between the first electrode and the second electrode is actively attenuated by gradually decreasing the value.   A desired time constant is set by using a TFT as a switching element connected to each pixel of the display device and adjusting a potential of a gate electrode of the TFT, and the first electrode is set according to the desired time constant. 3. The method according to claim 2, wherein the absolute value of the potential difference between the first electrode and the second electrode is gradually attenuated.   2. The method according to claim 1, wherein, when the display device is driven in an active matrix, an absolute value of a potential difference between the first electrode and the second electrode is gradually attenuated in accordance with two or more desired attenuation conditions. The driving method of the display device according to the above. The driving method according to any one of claims 1 to 6, wherein the dispersion includes a liquid and a plurality of charged electrophoretic particles, and at least a voltage is applied to form an electric field in the dispersion. A method for driving an electrophoretic display device including an electrode group including a first electrode and a second electrode.

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