JP2008224890A - Electrophoretic display device, controller, control method, and display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of suppressing the degradation of display quality. <P>SOLUTION: A voltage for particle dissociation or the like is applied to a common electrode and a pixel electrode prior to performance of an elimination step. With respect to this voltage applied immediately before the elimination step, a pulsating voltage rising in a positive direction and applied for a period T1 and a pulsating voltage rising in a negative direction and applied for a period T1 constitute a fundamental unit, and the pulsating voltage rising in the positive direction and the pulsating voltage rising in the negative direction are alternately applied, and the pulsating voltage rising in the positive direction is applied N1 times while the pulsating voltage rising in the negative direction is applied N2 times (N2<N1), and the pulsating voltage rising in the positive direction is applied first while the pulsating voltage rising in the same positive direction is applied last. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophoretic display device using an electrophoretic phenomenon or the like.

  As a display device for displaying characters, graphics, etc., for example, it is composed of a pair of electrodes arranged opposite to each other with a spacer or the like, and a display liquid containing colored particles or the like and sealed between the electrodes. Things are known. By the way, in such a display device, charged particles may gradually aggregate and dot-like defects may appear on the display. Further, the adhesion strength between the charged particles and the electrode increases with the lapse of time, and there is a possibility that a phenomenon of so-called seizure in which the charged particles stick firmly to the electrode may occur. Thus, a technique has been proposed in which an alternating voltage is applied to the electrode substrate immediately before the display state is changed to dissociate the aggregated charged particles or separate the charged particles from the electrodes (see, for example, Patent Document 1).

JP 2003-5227 A

By the way, even if an alternating voltage is applied to the electrode, depending on the application mode, the charged particles may not be sufficiently separated from the electrode, and image sticking may occur. As a result, a decrease in contrast occurs and the display quality deteriorates.
The present invention has been made to solve the technical problems as described above, and an object of the present invention is to provide an electrophoretic display device and the like capable of suppressing a reduction in display quality.

For this purpose, an electrophoretic display device to which the present invention is applied includes a first electrode and a second electrode disposed at a position facing the first electrode, and includes at least a dispersion medium and an electric field. An electrophoretic ink including charged particles that move due to an action is provided between the first electrode and the second electrode, and the first electrode and the second electrode of the electrophoretic display panel. Applying means for applying a voltage to the electrodes, and a plurality of voltages for moving the charged particles toward one electrode relative to the first electrode and the second electrode prior to display change of the electrophoretic display panel And a control means for controlling the application means so as to apply a voltage multiple times to the first electrode and the second electrode to move the charged particles toward the other electrode. The means is a means for moving charged particles toward one electrode. Add each of the time integration values (first addition value) obtained by adding each of the time integration values integrated with time and each time integration value that integrates the voltage for moving the charged particles toward the other electrode over time. The added value (second added value) is made different.
Here, the control means may be characterized in that when the charged particles are located on one electrode side, the first addition value is made smaller than the second addition value.

  From another point of view, an electrophoretic display device to which the present invention is applied includes a first electrode and a second electrode disposed at a position opposite to the first electrode, and at least a dispersion medium. An electrophoretic display panel in which an electrophoretic ink containing charged particles that move by the action of an electric field is disposed between the first electrode and the second electrode; and the first electrode of the electrophoretic display panel; Prior to changing the display of the electrophoretic display panel, the application means for applying a voltage to the second electrode, and the voltage for moving the charged particles toward one electrode and the charged particles moved toward the other electrode And a control means for controlling the application means so as to apply a voltage for applying a plurality of times, wherein the control means is such that the position of the charged particles after the plurality of times of application is greater than the position of the charged particles before the plurality of times of application. Charged particles headed by changing display And controlling the applying means so that the electrode side.

  Further, when the present invention is regarded as a control device, the control device to which the present invention is applied includes a first electrode and a second electrode disposed at a position opposite to the first electrode, and at least distributed An electrophoretic ink including a medium and charged particles that move by the action of an electric field is a control device that controls an electrophoretic display panel disposed between a first electrode and a second electrode. Application means for applying a voltage to the first electrode and the second electrode of the display panel, and a voltage for moving the charged particles toward one electrode a plurality of times prior to changing the display of the electrophoretic display panel. And a control means for controlling the application means so as to apply a voltage for moving the charged particles toward the other electrode a plurality of times, and the control means moves the charged particles toward the one electrode. Voltage application conditions (first mark The condition), the conditions of voltage application for moving toward the charged particles to the other electrode (second application conditions) characterized by varying the.

  Here, the control means makes at least one of the magnitude and the application time different between the voltage applied a plurality of times under the first application condition and the voltage applied a plurality of times under the second application condition. Can be characterized. The control means may be characterized in that when the charged particles are located on one electrode side, the number of times of application under the first application condition is less than the number of times of application under the second application condition. .

  When the present invention is regarded as a control method, the control method to which the present invention is applied is an electrophoretic ink including at least a first electrode, charged particles that move by the action of an electric field, and a dispersion medium that disperses the charged particles. Is a control method for controlling the application of voltage to an electrophoretic display panel comprising a second electrode disposed at a position opposite to the first electrode across the first electrode, prior to a display change in the electrophoretic display panel, A voltage for moving the charged particles in one direction is applied to the first electrode and the second electrode under the first application condition, and the first electrode and the second electrode are applied under the second application condition. A voltage for moving the charged particles in the other direction is applied to the electrode.

  Furthermore, when the present invention is regarded as a display system, the display system to which the present invention is applied includes an electrophoretic ink including at least a first electrode, charged particles that move by the action of an electric field, and a dispersion medium that disperses the charged particles. An electrophoretic display panel including a second electrode disposed at a position opposite to the first electrode across the electrode, and an application unit that applies a voltage to the first electrode and the second electrode of the electrophoretic display panel In order to move the charged particles in one direction prior to the display change in the electrophoretic display panel provided in each of the plurality of display devices and the plurality of display devices, according to the first application condition And a control terminal for controlling each of the applying means to apply a voltage according to a second application condition in order to apply a voltage and move the charged particles in the other direction.

  ADVANTAGE OF THE INVENTION According to this invention, the electrophoretic display apparatus etc. which can suppress the fall of display quality can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram showing an electrophoretic display device according to this embodiment.
The electrophoretic display device 1 shown in the figure is a display device that can reversibly change the visual state by the action of an electric field. The electrophoretic display device 1 is schematically composed of an electrophoretic display panel 10 and a control device 20 that controls the electrophoretic display panel 10. Such an electrophoretic display device 1 is used for an electronic shelf label used in, for example, a clock, a calendar, electronic paper, a supermarket, a convenience store, and the like.

Although details will be described later, the electrophoretic display panel 10 includes a common electrode 13, a pixel electrode 14, an electrophoretic ink 15 in which charged particles are dispersed, and the like, and displays characters, numbers, figures, and the like.
The control device 20 includes a driver 30 and a control unit 40 as main parts.
The driver 30 is in a state where two types of voltages are applied from a power supply unit (not shown), and the driver 30 is in a state where a plurality of switching units (not shown) are provided. Details of the driver 30 will be described later.

  The control unit 40 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) in which programs and the like are recorded, and controls the electrophoretic display panel 10 via the driver 30. Further, when a control terminal such as a host computer is separately provided outside the electrophoretic display device 1, the control unit 40 communicates with the control terminal via an interface unit (not shown).

Next, the electrophoretic display panel 10 and the driver 30 will be described in detail.
FIG. 2 is a diagram for explaining the electrophoretic display panel 10 and the driver 30. In addition, in this figure, illustration of the control part 40 shown in FIG. 1 is abbreviate | omitted.

  The electrophoretic display panel 10 in this embodiment is a panel that can obtain a desired display by controlling the direction of an electric field. In addition, the electrophoretic display panel 10 has advantages such as low manufacturing cost and a wide viewing angle as a normal printed matter. Further, the electrophoretic display panel 10 has a display memory property that allows the display to be maintained without applying power, and as a result, has an advantage of low power consumption.

  More specifically, the electrophoretic display panel 10 according to this embodiment includes a substrate 11, a counter substrate 12, a common electrode 13, a pixel electrode 14, and an electrophoretic ink 15 in which charged particles are dispersed. Yes. In addition, the electrophoretic display panel 10 has a gap material (not shown) for maintaining a gap between the substrates 11 and the counter substrate 12 at a specified value, and an end portion of the substrate 11 and the counter substrate 12. A sealing material (not shown) for preventing the electrophoretic ink 15 from leaking out is provided.

The substrate 11 is a member that becomes a base of the electrophoretic display panel 10 and has a function of supporting members such as the pixel electrode 14.
The counter substrate 12 is a member that serves as a base of the electrophoretic display panel 10, similarly to the substrate 11. The counter substrate 12 is disposed at a position facing the substrate 11 with the electrophoretic ink 15 in between. Further, the counter substrate 12 is attached to the substrate 11 through a predetermined gap. The counter substrate 12 has a function of supporting members such as the common electrode 13.

The common electrode 13 as an example of the first electrode is formed over the entire inner surface of the counter substrate 12. In addition, a predetermined voltage is applied from the driver 30 to the common electrode 13.
A plurality of pixel electrodes 14 as an example of the second electrode are provided on the inner surface of the substrate 11 and at a position facing the common electrode 13. Further, the pixel electrode 14 is configured to be applied with a predetermined voltage from the driver 30 in the same manner as the common electrode 13.

  Here, in the electrophoretic display panel 10, at least one side becomes a display surface (observation surface). For this reason, the substrate and the electrodes on the display surface side need to be transparent. This transparency is a concept including translucent and colored transparency. Therefore, in the present embodiment, the counter substrate 12 and the common electrode 13 are configured using a transparent material. In the present embodiment, the counter substrate 12 and the common electrode 13 are made of a transparent material and the counter substrate 12 side is used as a display surface. However, if the substrate 11 and the pixel electrode 14 are made of a transparent material, the other side is used. The side can also be a display surface. When flexibility is required for the electrophoretic display panel 10, a film-like or sheet-like resin substrate is used for the substrate 11 and the counter substrate 12.

For the substrate 11 and the counter substrate 12, for example, a resin material can be used. When transparency is required like the counter substrate 12 located on the display surface side, polyethylene terephthalate (PET), polyethersulfone (PES), polycarbonate (PC), or the like is used.
For the common electrode 13 and the pixel electrode 14, for example, a general conductive material such as aluminum or copper can be used. In addition, when transparency is requested | required like the common electrode 13 located in the display surface side, conductive oxides, such as ITO (indium tin oxide), etc. are used, for example. Of course, this conductive oxide can also be used for the pixel electrode 14.
The electrophoretic ink 15 is sealed between the substrate 11 and the counter substrate 12. The electrophoretic ink 15 includes positively charged white particles 15a, negatively charged black particles 15b, and a dispersion medium 15c that disperses these particles.

As the white particles 15a, for example, a white pigment such as titanium oxide, white resin particles, or resin particles colored in white can be used.
As the black particles 15b, for example, black pigments such as titanium black and carbon black, resin particles colored in black, and the like can be used.
In addition, these particles can be arbitrarily used in various colors as long as the contrast can be displayed, and can be a combination of white and red, white and blue, yellow and black, and the like.
For the dispersion medium 15c, various low-dielectric constant organic solvents conventionally used for electrophoretic display can be used. For the dispersion medium 15c, additives such as a dispersant and a charge control agent are used. Can also be used.

  The driver 30 receives a command from the control unit 40 and applies a voltage to the common electrode 13 and each pixel electrode 14. The driver 30 includes a plurality of switching units (not shown) that can select one voltage from two types of voltages (Vp, Vs) applied from a power source unit (not shown), and corresponds to each switching unit. A plurality of output terminals (not shown) provided. The driver 30 functions as one application unit. One voltage selected by each switching unit is applied to the common electrode 13 and the pixel electrode 14 via the output terminal. Here, in the present embodiment, 50 V is applied to the driver 30 as the voltage Vp, and 0 V (ground voltage) is applied as the voltage Vs.

Next, the operation of the electrophoretic display panel 10 in the present embodiment will be described.
FIG. 3 is a diagram for explaining the operation of the electrophoretic display panel 10.
As described above, a voltage is applied from the driver 30 to the common electrode 13 and the pixel electrode 14 in the present embodiment. Several methods have been proposed for applying a voltage. In the present embodiment, one voltage is selectively applied from two types of voltages not only to the pixel electrode 14 but also to the common electrode 13. So-called common swing is adopted.

First, when displaying on the electrophoretic display panel 10 according to the present embodiment, first, a reset operation for displaying the whole as white is performed, and then a display operation is performed. Then, after the display operation is performed, the display change operation for changing the display is repeated.
When performing the reset operation, as shown in FIG. 3A, the voltage Vs (= 0 V) is applied to the common electrode 13 and the voltage Vp (= 50 V) is applied to all the pixel electrodes 14. . As a result, an electric field is generated from the pixel electrode 14 toward the common electrode 13, the positively charged white particles 15 a move toward the common electrode 13, and the negatively charged black particles 15 b move toward the pixel electrode 14. . For this reason, the white particles 15a are located on the common electrode 13 side located on the display surface side, and the entire display is white. When the reset operation is performed, the voltage Vs and the voltage Vp are applied for about 0.5 seconds. In this embodiment, positively charged white particles 15a and negatively charged black particles 15b are used. However, such a charged state is an example, and the white particles 15a can be negatively charged. In addition, the black particles 15b can be positively charged.

  Next, a display operation is performed. In the present embodiment, an operation when part of the display is black will be described. When a part of white display is black display, as shown in FIG. 3B, the voltage Vp (= 50 V) with respect to the common electrode 13 and the pixel electrode 14 corresponding to the region where black display is to be performed (FIG. The voltage Vs (= 0 V) with respect to the middle center pixel electrode 14), and the voltage Vp (at the pixel electrode 14 at both ends in the figure) corresponding to the area where the display is not changed (area where the display is maintained). = 50V) is applied. When the display operation is performed, the voltage Vs and the voltage Vp are applied for 0.5 seconds.

  As a result, an electric field from the common electrode 13 toward the pixel electrode 14 is generated between the pixel electrode 14 to which the voltage Vs (= 0 V) is applied and the common electrode 13, and black display is performed in the portion where the electric field is generated. . Further, the pixel electrode 14 to which the voltage Vp (= 50 V) is applied and the common electrode 13 are substantially equipotential. That is, the electric field strength is substantially zero. For this reason, the movement of the white particles 15a and the black particles 15b is suppressed, and the black display is not performed in this portion, and the white display is maintained. Then, after such a display operation is performed, a display change operation for changing the display is repeated.

  Next, the display change operation will be described. The display change operation in the present embodiment includes a step of changing black display that needs to be erased to white display (hereinafter referred to as “erase step”) and a step of changing white display to black display (hereinafter referred to as “write”). This is comprised of two steps. In these two steps, the erasing step is performed before the writing step.

FIG. 4 is a diagram for explaining the display change operation.
FIG. 4A shows the state of the electrophoretic display panel 10 in the erasing step.
In this erasing step, the voltage Vs (= 0 V) is applied to the common electrode 13, and the voltage Vp (= 50 V) is applied to the pixel electrode 14 corresponding to the area to be changed to white display (display erasing area). The Further, the voltage Vs (= 0 V) is applied to the pixel electrode 14 corresponding to an area other than the area where the display is changed to white display (area where the display state is maintained). As a result, the predetermined area is changed to white display, and the display state is maintained in areas other than the predetermined area.

  For example, when the black display at the center in the figure is changed to white display and the display is erased, the voltage Vs (= 0 V) is applied to the common electrode 13 and the voltage Vp (= 50 V) is applied to the pixel electrode 14 at the center in the figure. Is applied. As a result, the black display at the center in the figure is changed to white display. In addition, the same voltage Vs (= 0 V) as the voltage applied to the common electrode 13 is applied to the pixel electrodes 14 at both ends in the figure, and the display state is in a region corresponding to the pixel electrodes 14 located at both ends. Maintained.

Next, the writing step will be described.
FIG. 4B shows the state of the electrophoretic display panel 10 in the writing step.
In the writing step, the voltage Vp (= 50V) is applied to the common electrode 13, and the voltage Vs (= 0V) is applied to the pixel electrode 14 corresponding to the region to be changed to black display. In addition, the voltage Vp (= 50 V) is applied to the pixel electrode 14 corresponding to an area other than the area where the display is changed to black display (area where the display state is maintained). As a result, the predetermined area is changed to black display, and the display state is maintained in areas other than the predetermined area.

  For example, when the white display at the right end in the drawing is changed to the black display and writing is performed, the voltage Vp (= 50 V) is applied to the common electrode 13 and the voltage Vs (= 0 V) is applied to the pixel electrode 14 at the right end in the drawing. Is done. As a result, the white display at the right end in the figure is changed to black display. Further, the same voltage Vp (= 50 V) as the voltage applied to the common electrode 13 is applied to the pixel electrode 14 at the center and the left end in the drawing, and in the region corresponding to the pixel electrode 14 located at the center and the left end in the drawing. The display state is maintained.

  By the way, in the electrophoretic display panel 10 according to the present embodiment, charged particles (white particles 15a and black particles 15b) may gradually aggregate over time, resulting in dot-like defects in the display. Further, as the time passes, the adhesion strength between the charged particles and the common electrode 13 (pixel electrode 14) increases, and so-called image sticking in which the charged particles adhere firmly to the common electrode 13 (pixel electrode 14) may occur. As a result, a decrease in contrast occurs and the display quality deteriorates. Therefore, a technique has been proposed in which an alternating voltage that switches between positive and negative is applied to the electrode immediately before the display state is changed, and the particles are separated from the electrode. However, even if the alternating voltage is applied, depending on the application mode, the particles may not be sufficiently separated from the electrode.

  For example, in the display state shown in FIG. 3B, when an alternating voltage that switches between positive and negative is applied to the common electrode 13 and the pixel electrode 14 positioned at the right end in the figure, first, Vs (= 0V), a pulsed voltage to which Vp (= 50 V) is applied to the pixel electrode 14 can be applied. However, in this case, since an electric field is formed from the pixel electrode 14 toward the common electrode 13, the white particles 15 a try to move to the common electrode 13 side and the black particles 15 b try to move to the pixel electrode 14. As a result, the white particles 15a are pressed against the common electrode 13 and the black particles 15b are pressed against the pixel electrode 14, and the adhesion strength between the white particles 15a and the common electrode 13 and the adhesion strength between the black particles 15b and the pixel electrode 14 are increased. There is a fear.

  For this reason, even if the remaining pulsed voltage constituting the alternating voltage is applied a plurality of times, the white particles 15a cannot be separated from the common electrode 13 and the black particles 15b cannot be separated from the pixel electrode 14, resulting in burn-in. May end up. As a result, for example, when black display is performed, the white particles 15a adhering to the common electrode 13 are mixed in the black particles 15b, and the contrast is lowered. In addition, the contrast is lowered due to a lack of movable (driveable) particles.

  Further, when an alternating voltage that switches between positive and negative is applied a plurality of times, a pulse shape in which Vs (= 0 V) is applied to the common electrode 13 and Vp (= 50 V) is applied to the pixel electrode 14 at the end of the plurality of times of application. It is also possible to apply a voltage of However, in this case as well, an electric field from the pixel electrode 14 toward the common electrode 13 is formed, so that the white particles 15a try to move toward the common electrode 13 and the black particles 15b try to move toward the pixel electrode 14. For this reason, a part of the white particles 15a may adhere to the common electrode 13 again, or a part of the black particles 15b may adhere to the pixel electrode 14 again.

  Further, when the white particles 15a are still attached to the common electrode 13, the adhesion strength between the white particles 15a and the common electrode 13 is increased, and when the black particles 15b are still attached to the pixel electrode 14, the black particles are added. The adhesion strength between 15b and the pixel electrode 14 increases. As a result, as described above, for example, when black display is performed, the white particles 15a attached to the common electrode 13 are mixed in the black particles 15b, and the contrast is lowered. In addition, the contrast is lowered by the lack of movable (driveable) particles.

Therefore, in the present embodiment, a voltage that can suppress the occurrence of the above-described problems is applied.
FIG. 5 shows voltages applied to the common electrode 13 and the pixel electrode 14. In this figure, the applied voltage (V) is positive when the electric field is formed from the pixel electrode 14 toward the common electrode 13, and the electric field is formed from the common electrode 13 toward the pixel electrode 14. The case is shown as negative.

  As described above, the display change operation in the present embodiment includes the erasing step and the writing step. In this embodiment, prior to the erasing step and prior to the writing step, a voltage is applied to dissociate the aggregated charged particles and separate the charged particles from the electrodes.

As described above, the voltage for dissociating particles is applied to the common electrode 13 and the pixel electrode 14 prior to the execution of the erase step (hereinafter, applied to the common electrode 13 and the pixel electrode 14 prior to the execution of the erase step). This voltage is referred to as “the voltage immediately before the erasing step”).
As shown in the figure, the voltage immediately before the erasing step rises in the positive direction, that is, a pulse voltage that forms an electric field from the pixel electrode 14 toward the common electrode 13 (hereinafter, this pulse voltage is referred to as “positive direction pulse voltage”). And a pulse voltage that rises in the negative direction, that is, forms an electric field from the common electrode 13 toward the pixel electrode 14 (hereinafter, this pulse voltage is referred to as a “negative pulse voltage”). This is the voltage with which the basic unit is constructed. Note that the application time of the pulse voltage rising in the positive direction and the pulse voltage rising in the negative direction are both T1.

  Further, the voltage just before the erasing step is a state in which the pulse voltage rising in the positive direction and the pulse voltage rising in the negative direction are alternately applied. In other words, the voltage immediately before the erase step in the present embodiment is in a state where an alternating voltage is applied. In addition, the voltage in this embodiment is an example, and it is of course possible to apply a voltage other than an alternating voltage.

Further, the voltage immediately before the erasing step is such that the positive pulse voltage is applied N1 times and the negative pulse voltage is applied N2 times, which is 1 less than N1. The application conditions of the direction pulse voltage and the negative direction pulse voltage are different.
In addition, the voltage immediately before the erasing step is in a state where the positive pulse voltage is first applied and finally the positive pulse voltage is also applied. As a result, the voltage immediately before the erasure step in the present embodiment is obtained by integrating the time-integrated values obtained by integrating the positive-direction pulse voltage with time, and integrating the negative-direction pulse voltage with time. It is in a state larger than the added value obtained by adding each of the time integral values. In other words, in this embodiment, the product of the time integral value of the positive direction pulsed voltage and the number of application times of the positive direction pulsed voltage, the time integration value of the negative direction pulsed voltage and the number of application times of the negative direction pulsed voltage, When the product is compared, the former is larger than the latter. This magnitude relationship is the case where absolute values are compared.

  The voltage immediately before the erasing step in the present embodiment is such that, for example, the white particles 15a are located on the pixel electrode 14 side and the black particles 15b are located on the common electrode 13 side, as in the central display region of FIG. The pixel electrode 14 in the display region in which the movement of the white particles 15a to the common electrode 13 side, the movement of the black particles 15b to the pixel electrode 14 side is scheduled in the later erasing step, Applied to the electrode 13.

  When the application of the voltage immediately before the erasing step is started, as described above, since the positive direction pulse voltage is applied first, the pixel electrode 14 is connected to the common electrode 13 between the common electrode 13 and the pixel electrode 14. An incoming electric field is first formed. As a result, for example, when the black particles 15b are located on the common electrode 13 side and the white particles 15a are located on the pixel electrode 14 side as in the display region located in the center of FIG. Move toward the common electrode 13, and the black particles 15 b move toward the pixel electrode 14. In other words, the white particles 15 a move in a direction away from the pixel electrode 14, and the black particles 15 b move in a direction away from the common electrode 13.

Next, in this embodiment, a negative pulse voltage is applied, and a pulse voltage that switches between positive and negative is applied a plurality of times following this pulse voltage. As a result, the aggregated particles are dissociated or the white particles 15a and the black particles 15b attached to the common electrode 13 and the pixel electrode 14 are separated due to collisions between the particles.
In the present embodiment, the positive pulse voltage is applied last. As a result, the white particles 15 a finally move in the direction away from the pixel electrode 14, and the black particles 15 b finally move in the direction away from the common electrode 13. As a result, after the application of the voltage immediately before the erase step, the white particles 15a are closer to the common electrode 13 than the initial position (before the voltage immediately before the erase step is applied), and the black particles 15b are closer to the pixel electrode 14 than the initial position. Come to be located.

  In this embodiment, as described above, the white particles 15a are first moved away from the pixel electrodes 14 and the black particles 15b are first moved away from the common electrode 13 by first applying a positive pulse voltage. For this reason, generation | occurrence | production of malfunctions, such as the increase in the adhesion strength of the white particle 15a and the pixel electrode 14, and the increase in the adhesion strength of the black particle 15b and the common electrode 13, can be suppressed. First, the white particles 15 a and the black particles 15 b are moved between the common electrode 13 and the pixel electrode 14 by moving the white particles 15 a from the pixel electrode 14 and moving the black particles 15 b away from the common electrode 13. It floats and becomes easy to vibrate (move). As a result, the vibration width (movement width) when a positive and negative alternating pulse voltage is applied later is increased, and the collision frequency between particles is increased, compared to the state where they are attached to the common electrode 13 and the pixel electrode 14. it can. For this reason, dissociation of the aggregated charged particles (white particles 15a, black particles 15b) and separation of the charged particles from the electrode can be promoted.

  In the present embodiment, as described above, an electric field directed from the pixel electrode 14 toward the common electrode 13 is formed by applying a positive pulse voltage at the end. For this reason, the white particles 15 a move from the pixel electrode 14 and the black particles 15 b move away from the common electrode 13 immediately before the application of the voltage immediately before the erasing step. As a result, redeposition of the white particles 15a to the pixel electrode 14 and redeposition of the black particles 15b to the common electrode 13 are suppressed as compared with those not having the configuration of the present embodiment. As a result, it is possible to suppress the occurrence of problems such as a decrease in contrast as compared with those not having the configuration of the present embodiment.

  Furthermore, in the present embodiment, after the application of the voltage immediately before the erasing step is finished, the white particles 15a are separated from the pixel electrode 14 and closer to the common electrode 13 than the original position, and the black particles 15b are separated from the common electrode 13 and from the original position. Is also located on the pixel electrode 14. That is, the white particles 15a and the black particles 15b are located on the counter electrode side from the initial position. As a result, when the erasing step is performed later, this erasing step can be performed smoothly. Further, the white particles 15a and the black particles 15b can be moved to the counter electrode even in a state where the voltage value of the voltage applied when performing the erasing step later is lowered or in a state where the voltage application time is shortened. That is, the amount of energy required for the erasing step can be reduced as compared with that not having the configuration of the present embodiment. Further, as described above, the voltage application time in the erasing step can be shortened, so that the operation time in the erasing step can be shortened, and the display changing operation including the erasing step can be performed in a shorter time. It becomes possible.

  Although the voltage immediately before the erase step has been described above, the voltage for separating the particles from the electrode is applied even before the write step as described above (hereinafter, the common electrode 13 and the pixel electrode prior to the execution of the write step). 14 is referred to as “voltage immediately before the writing step”). As shown in FIG. 5, the voltage immediately before the writing step rises in the negative direction, that is, rises in the positive direction, that is, a negative pulse voltage of application time T1 that forms an electric field from the common electrode 13 toward the pixel electrode 14, that is, A basic unit is composed of a positive-direction pulsed voltage of the application time T1 that forms an electric field from the pixel electrode 14 toward the common electrode 13.

  Further, the negative pulse voltage and the positive pulse voltage are alternately applied to the voltage immediately before the writing step. In other words, the voltage applied immediately before the writing step in the present embodiment is in a state where an alternating voltage is applied. Further, the voltage just before the writing step is such that the negative direction pulse voltage is applied N1 times, and the positive direction pulse voltage is applied N2 times, which is 1 less than N1. In addition, the voltage immediately before the writing step is such that a negative direction pulse voltage is first applied and finally a negative direction pulse voltage is applied.

  The voltage immediately before the writing step in the present embodiment is such that, for example, the white particles 15a are located on the common electrode 13 side and the black particles 15b are located on the pixel electrode 14 side, as in the rightmost display region in FIG. The pixel electrode 14 and the common electrode in the display area in which the movement of the white particles 15a to the pixel electrode 14 and the movement of the black particles 15b to the common electrode 13 are scheduled in a later writing step. 13 is applied.

  When the application of the voltage immediately before the writing step is started, a negative direction pulse voltage is first applied as shown in FIG. 5, so that the common electrode 13 goes to the pixel electrode 14 between the common electrode 13 and the pixel electrode 14. An electric field is formed. As a result, in the display area at the right end in FIG. 3B, the white particles 15 a move toward the pixel electrode 14 and the black particles 15 b move toward the common electrode 13. In other words, the white particles 15 a move in a direction away from the common electrode 13, and the black particles 15 b move in a direction away from the pixel electrode 14.

  Next, in the present embodiment, a positive pulse voltage is applied, and a pulse voltage that switches between positive and negative is applied a plurality of times following this pulse voltage. As a result, since the white particles 15a and the black particles 15b vibrate, dissociation of the aggregated particles and separation of the particles adhering to the common electrode 13 and the pixel electrode 14 are performed due to collision between the particles. In this embodiment, a negative direction pulse voltage is applied last. As a result, the white particles 15 a finally move away from the common electrode 13, and the black particles 15 b finally move away from the pixel electrode 14. Therefore, after the application of the voltage immediately before the writing step is finished, the white particles 15a are closer to the pixel electrode 14 than the initial position (before the voltage immediately before the writing step is applied), and the black particles 15b are closer to the common electrode 13 than the initial position. Come to be located.

  As a result, as in the case of the voltage immediately before the erasing step, the occurrence of problems such as an increase in the adhesion strength between the white particles 15a and the common electrode 13 and an increase in the adhesion strength between the black particles 15b and the pixel electrode 14 is performed in this embodiment. It can suppress compared with what does not have a structure of a form. Further, dissociation of the aggregated charged particles and separation of the charged particles from the electrode can be promoted. Furthermore, the redeposition of the white particles 15a to the common electrode 13 and the redeposition of the black particles 15b to the pixel electrode 14 can be suppressed as compared with those not having the configuration of the present embodiment. For this reason, the occurrence of problems such as a decrease in contrast can be suppressed by the voltage application mode of the present embodiment. Further, when the writing step is performed later, this writing step can be performed smoothly. Furthermore, the amount of energy required for the writing step can be reduced. Further, the operation time in the writing step can be shortened, and the display changing operation including the writing step can be performed in a shorter time.

  Here, the present inventor conducted the following experiment to verify the effect of the present embodiment. More specifically, the inventor applied the voltage in the mode shown in FIG. 5 and acquired the contrast value (Example). On the other hand, the present inventor repeatedly applied a voltage in a conventional manner to obtain a contrast value (comparative example). Here, the experimental conditions in Examples and Comparative Examples will be described in detail with reference to FIG.

FIG. 6 schematically shows experimental conditions in Examples and Comparative Examples.
Experimental conditions (A1) in Examples: First, predetermined display was performed on the electrophoretic display panel 10.
(A2): After performing a predetermined display in A1, the pixel electrode 14 corresponding to the predetermined display area A in the electrophoretic display panel 10 and the common electrode 13 (hereinafter, these electrodes are referred to as “corresponding electrodes”). The voltage immediately before the first erase step was applied. Thereafter, the first erasing step was performed on the display area A, and the display area A that had been displayed in black was set as white display.
(A3) Next, a voltage immediately before the first writing step was applied to the corresponding electrode. Thereafter, the first writing step was executed in this display area A, and the display area A that had been displayed in white was changed to black display.

(A4) After that, the procedure in A2 and A3 was set as one voltage application unit, and this voltage application unit was repeated a plurality of times. Then, after the erasing step at the 1000th time is finished, arbitrary three points are selected in the display area A, and the Y value of the XYZ color system (hereinafter referred to as “the Y value of the XYZ color system”) is simply set at these three points. (Referred to as “Y value”). And the average value of three measured Y values was acquired. Note that when the 1000th erasing step is completed, the display area A is in white display, and therefore, in this step, the Y value in white display is acquired.
(A5) Next, after the writing step at the 1000th time was completed, Y values were acquired at almost the same locations as the arbitrary three points selected in A4. And the average value of three measured Y values was acquired. When the 1000th writing step is completed, the display area A is displayed in black, and in this step, the Y value in black display is acquired.
(A6) Then, division [average value of Y values acquired at A4] / [average value of Y values acquired at A5] was performed to obtain a contrast value.

(A7) Thereafter, the above one unit was further repeated, and the above processing A4 was performed after the end of the 2000th erasing step, and the above processing A5 was performed after the end of the 2000th writing step. Thereafter, a contrast value was obtained in the same manner as A6. Further, the contrast values were also obtained in the 3000th and 4000th times.
(A8) As shown in (a1), the voltage immediately before the erasing step in the present embodiment is 11 times the positive direction pulse voltage with the application time T1 = 10 ms, and the negative direction pulse voltage with the application time T1 = 10 ms. It was set as the aspect applied 10 times. In addition, as shown in (a2), the voltage immediately before the writing step in the present embodiment is applied 10 times as the positive direction pulse voltage with the application time T1 = 10 ms and 11 times as the negative direction pulse voltage with the application time T1 = 10 ms. It was set as the mode to do.

Experimental conditions (B1) in the comparative example In the comparative example, the same processing as A1 to A7 described above was performed.
(B2) However, as shown in (b1), the voltage immediately before the erasing step in the comparative example is 10 times the positive direction pulse voltage with the application time T1 = 10 ms and 10 times the negative direction pulse voltage with the application time T1 = 10 ms. It was set as the aspect to apply. Further, as shown in (b2), the voltage immediately before the writing step in the comparative example is a mode in which a positive direction pulse voltage with an application time T1 = 10 ms is applied 10 times and a negative direction pulse voltage with an application time T1 = 10 ms is applied 10 times. It was.

The conditions common to the examples and comparative examples are as follows.
White particles 15a: Titanium oxide (average diameter 0.3 μm to 0.5 μm)
Black particles 15b: acrylic resin particles colored with carbon black (average diameter 5 μm)
・ Dispersion medium 15c: xylene ・ Gap between common electrode 13 and pixel electrode 14: 50 μm
・ Voltage value just before erase step ... ± 50V
・ Applied voltage in erase step: + 50V
-Voltage application time in erase step: 0.5 seconds-Voltage value of voltage immediately before write step: ± 50V
-Applied voltage in writing step (-) 50V
-Voltage application time in writing step: 0.5 seconds-Y value measurement method-Measurement was performed by the method according to JIS Z8722 under the following conditions.
・ Measuring equipment: Suga Test Instruments Co., Ltd. MSC-IS-2B
・ Light source: 12V50W halogen lamp ・ Colorimetric conditions: D65 light 10 ° field of view ・ Measurement area: 5φ
・ Standard white surface ... Included white standard plate

Here, the result of the experiment will be described.
FIG. 7 is an explanatory diagram showing experimental results in Examples and Comparative Examples.
As shown in the figure, after the 1000th voltage application, the contrast value in the example was 11.12, and the contrast value in the comparative example was 8.92. That is, the contrast value in the example was larger than the contrast value in the comparative example. Further, after the 2000th voltage application was completed, the value was 10.59 in the example and 7.79 in the comparative example, and the contrast value in the example was larger than the contrast value in the comparative example. Similarly, even after the 3000th and 4000th voltage application, the contrast value in the example was larger than the contrast value in the comparative example.

  Furthermore, the present inventor used the calculation formula [(contrast value at the 4000th time) / (contrast value at the 1000th time)] × 100 [%] in both the examples and the comparative examples to determine the degree of decrease in the contrast value. investigated. As a result, it was 89.6 [%] in the example, and 77.5 [%] in the comparative example, and it was found that the example can maintain contrast compared to the comparative example.

When burn-in occurs, the contrast decreases. In other words, the contrast (value) decreases as the degree of image sticking increases, and the contrast (value) increases as the degree of image sticking decreases. Also, the greater the degree of burn-in, the greater the degree of decrease in contrast value.
In the experiment, as described above, it was confirmed that any of the contrast values in the example exceeded the contrast value in the comparative example. It was also found that the example can maintain contrast compared to the comparative example. For this reason, it can be seen that the voltage application mode in the present embodiment can suppress the occurrence of image sticking compared to the conventional application mode.

  Note that this embodiment can also be understood as follows. An electrophoretic ink comprising a first electrode and a second electrode disposed at a position opposite to the first electrode, wherein the electrophoretic ink includes at least a dispersion medium and charged particles that move by the action of an electric field. A control device for controlling the electrophoretic display panel disposed between the first electrode and the second electrode, and applying means for applying a voltage to the first electrode and the second electrode of the electrophoretic display panel; Prior to changing the display of the electrophoretic display panel, a voltage for moving the charged particles toward one electrode is applied a plurality of times, and a voltage for moving the charged particles toward the other electrode is applied a plurality of times. Control means for controlling the application means, and the control means alternates a voltage for moving the charged particles toward one electrode and a voltage for moving the charged particles toward the other electrode. Control the application means to apply to In addition, when the charged particles are located on one electrode side, the number of times of applying the voltage for moving the charged particles toward one electrode is N, and the voltage for moving the charged particles toward the other electrode The number of times of application is (N + 1).

Next, 2nd Embodiment and 3rd Embodiment are described using FIG.
FIG. 8 shows a voltage application form in the second and third embodiments. FIG. 8A shows a voltage application form in the second embodiment, and FIG. 8B shows a voltage application form in the third embodiment.

FIG. 8A shows a voltage application mode in the second embodiment as described above. This figure shows the voltage immediately before the erase step.
More specifically, the voltage immediately before the erasing step in the present embodiment is composed of a basic unit composed of a positive-direction pulsed voltage at the application time T2 and a negative-direction pulsed voltage at the application time T3, and this basic unit is continued multiple times. It has become a state. In other words, the voltage immediately before the erasing step in the present embodiment is a state in which the positive pulse voltage at the application time T2 and the negative pulse voltage at the application time T3 are alternately applied. That is, as in the first embodiment, a voltage is applied alternately. Note that the voltage immediately before the erasing step in the present embodiment is such that the application time T2 of the positive direction pulse voltage is longer than the application time T3 of the negative direction pulse voltage.

Here, the state of the electrophoretic display panel 10 when the voltage immediately before the erasing step in the present embodiment is applied will be described with reference to FIG.
For example, when application of the voltage immediately before the erasing step in the present embodiment is started with respect to the pixel electrode 14 and the common electrode 13 corresponding to the central display region in FIG. The white particles 15 a move toward the common electrode 13 and the black particles 15 b move toward the pixel electrode 14.

  Next, when a negative direction pulse voltage is applied, the white particles 15 a move to the pixel electrode 14 and the black particles 15 b move to the common electrode 13. As described above, the positive direction pulse voltage application time T2 and the negative direction pulse voltage application time T3 satisfy T2> T3. For this reason, for example, the movement amount of the white particles 15a when the positive direction pulse voltage is applied is larger than the movement amount (return amount) of the white particles 15a when the negative direction pulse voltage is applied. Become.

  As a result, after the application of the negative direction pulse voltage, the white particles 15a are located closer to the common electrode 13 than the initial position (before application of the voltage immediately before the erasing step). The same applies to the black particles 15b, and the black particles 15b are positioned on the pixel electrode 14 from the initial position. Thereafter, the positive direction pulse voltage and the negative direction pulse voltage are alternately repeated.

  Since these pulse voltages also have a relationship of T2> T3 in the present embodiment, the white particles 15a move toward the common electrode 13 as the pulse voltages are alternately applied. The particles 15b move gradually toward the pixel electrode 14. That is, the white particles 15 a and the black particles 15 b gradually move toward the inner direction of the gap formed between the common electrode 13 and the pixel electrode 14. As a result, after the application of the voltage immediately before the erasing step is finished, the white particles 15 a are located at a position away from the pixel electrode 14, and the black particles 15 b are located at a position away from the common electrode 13.

  In the present embodiment, as in the first embodiment, the pulse voltage is first raised in the positive direction. That is, instead of the voltage that presses the white particles 15a to the pixel electrode 14 and the black particles 15b to the common electrode 13, a voltage that separates the white particles 15a from the pixel electrode 14 and the black particles 15b from the common electrode 13 is applied. For this reason, similarly to the first embodiment, the problem that the adhesion strength between the white particles 15a and the pixel electrode 14 increases and the problem that the adhesion strength between the black particles 15b and the common electrode 13 increases are generated. Can be suppressed.

  First, the white particles 15 a and the black particles 15 b are moved to the common electrode 13 and the pixel electrode 14 by moving the white particles 15 a away from the pixel electrode 14 and the black particles 15 b away from the common electrode 13. It floats between and becomes in a state where it tends to vibrate (move). As a result, the vibration width (movement width) when a positive and negative alternating pulse voltage is applied later is increased, and the collision frequency between charged particles can be increased as compared with the case where the electrodes are attached to the electrode. For this reason, dissociation of the aggregated charged particles and separation of the charged particles from the electrode can be promoted.

  In the present embodiment, after the first positive pulse voltage is applied and then the first negative pulse voltage is applied, the white particles 15a are initially (before the application of the applied voltage immediately before the erasing step). It is located closer to the common electrode 13 than the position of. Further, the black particles 15b are positioned closer to the pixel electrode 14 than the initial position. As a result, the redeposition of the white particles 15a to the pixel electrode 14 and the redeposition of the black particles 15b to the common electrode 13 can be suppressed as compared with the first embodiment.

  In the present embodiment, the white particles 15a gradually move toward the common electrode 13 and the black particles 15b gradually move toward the pixel electrode 14 with the application of the pulse voltage. That is, the white particles 15a and the black particles 15b gradually move to the counter electrode side. For this reason, after the application of the voltage immediately before the erasing step is finished, the white particles 15a and the black particles 15b are positioned closer to the counter electrode than the initial position. As a result, the white particles 15a and the black particles 15b can be moved to the counter electrode even in a state where the voltage value of the voltage applied when the erasing step is performed later is lowered or in a state where the voltage application time is shortened. . That is, the amount of energy required for the erasing step can be reduced. Further, as described above, the voltage application time in the erasing step can be shortened, so that the operation time in the erasing step can be shortened, and the display changing operation including the erasing step can be performed in a shorter time. It becomes possible.

  Also in this embodiment, when the same experiment as described above was performed, it was confirmed that the contrast value in this embodiment was larger than the contrast value in the conventional application mode. In this embodiment, the application of the voltage immediately before the erasure step is finished with the negative direction pulse voltage last, but the positive direction pulse voltage is applied again and the pulse voltage rising in the positive direction is finally erased. The application of the voltage immediately before the step can be terminated. Although a detailed description is omitted, immediately before the writing step, a negative direction pulse voltage of application time T2 is first applied, and a positive direction pulse voltage of application time T3 is applied after this pulse voltage. The Then, the negative direction pulse voltage and the positive direction pulse voltage are alternately applied a plurality of times.

Next, a third embodiment will be described.
FIG. 8B shows a voltage application mode in the third embodiment. This figure shows the voltage immediately before the erase step.

  More specifically, the voltage immediately before the erasing step in the present embodiment is composed of a basic unit from a positive direction pulse voltage of magnitude V1, application time T4 and a negative direction pulse voltage of magnitude V2, application time T4, This basic unit is in a continuous state several times. In other words, the voltage immediately before the erasing step in the present embodiment is a state in which a positive pulse voltage of magnitude V1 and application time T4 and a negative pulse voltage of magnitude V2 and application time T4 are alternately applied. It has become. In the present embodiment, the application time of the positive direction pulse voltage and the application time of the negative direction pulse voltage are T4, and both are in the same state. Further, the absolute value of the voltage value V1 of the positive direction pulse voltage is in a state larger than the absolute value of the voltage value V2 of the negative direction pulse voltage.

Here, the state of the electrophoretic display panel 10 when the voltage of the present embodiment is applied will be described with reference to FIG.
For example, when voltage application is started in the form of the present embodiment with respect to the central display region in FIG. 3B, the white particles 15a are applied to the common electrode 13 and the black particles 15b by the first positive pulse voltage. Moves toward the pixel electrode 14. Next, when a negative direction pulse voltage is applied, the white particles 15 a move to the pixel electrode 14 and the black particles 15 b move to the common electrode 13. As described above, since the voltage value V1 of the positive direction pulse voltage and the voltage value V2 of the negative direction pulse voltage are absolute values of V1> V2, the movement of the white particles 15a by the positive direction pulse voltage is performed. The amount is larger than the moving amount (return amount) of the white particles 15a due to the negative direction pulse voltage. Further, the amount of movement of the black particles 15b due to the positive direction pulsed voltage is larger than the amount of movement (return amount) of the black particles 15b due to the negative direction pulsed voltage.

  For this reason, after the application of the negative direction pulse voltage, the white particles 15a are positioned closer to the common electrode 13 than the initial position (before voltage application immediately before the erasing step). Further, after the application of the negative direction pulse voltage, the black particles 15b are positioned closer to the pixel electrode 14 than the initial position. Thereafter, the positive direction pulse voltage and the negative direction pulse voltage are applied alternately. Since these pulse voltages also have a relationship of absolute value V1> V2 in this embodiment, the white particles 15a are directed toward the common electrode 13 as the pulse voltage is alternately repeated. The black particles 15 b move gradually toward the pixel electrode 14. As a result, after the application of the voltage immediately before the erasing step is finished, the white particles 15 a are located at a position away from the pixel electrode 14, and the black particles 15 b are located at a position away from the common electrode 13.

  Here, in this embodiment, the application of the voltage is terminated lastly with the positive direction pulsed voltage, but the application of the voltage can be terminated lastly with the negative direction pulsed voltage. Although a detailed description is omitted, immediately before the writing step, a negative direction pulsed voltage having a voltage value V1 is first applied, and after this negative direction pulsed voltage, a positive direction pulsed voltage having a voltage value V2 is applied. Applied. Immediately before the writing step, the negative direction pulse voltage and the positive direction pulse voltage are alternately applied a plurality of times. According to the present embodiment, it is possible to achieve the same effects as those of the second embodiment, such as the dissociation of the aggregated particles and the promotion of the separation of the particles from the electrode. Also in this embodiment, when the same experiment as described above was performed, it was confirmed that the contrast value in this embodiment was larger than the contrast value in the conventional application mode.

  In addition, although the voltage value of the positive direction pulse voltage and the negative direction pulse voltage in the above embodiment is constant, it can be varied during the application. Also, the voltage value can be varied for each application. Furthermore, although the application times T1, T2, T3, and T4 of the positive direction pulse voltage and the negative direction pulse voltage in the above embodiment are constant, the application time can be varied for each application.

Here, in the said embodiment, it was set as the structure which provides the timer part (not shown) which manages the application time T1 etc. in the control part 40. FIG. By the way, it can also be set as the structure which provides a timer part other than the control part 40. FIG. Hereinafter, this point will be described.
FIG. 9 is a schematic configuration diagram showing an outline of a display system configured by a plurality of electrophoretic display devices 1.
As shown in the figure, this display system includes a plurality of (three in this embodiment) electrophoretic display devices 1 connected to a network, and each of the electrophoretic display devices 1 that are also connected to a network. And a control terminal 70 to be controlled.

Each electrophoretic display device 1 includes an electrophoretic display panel 10 and a control device 20 in the same manner as the electrophoretic display device 1 shown in FIG. The control device 20 includes a driver 30 and a control unit 40. In addition, the control device 20 in the present embodiment includes an interface unit 50 that connects the control unit 40 and the control terminal 70 and enables communication between the control unit 40 and the control terminal 70. The configuration and function of each device (each unit) are the same as those of the electrophoretic display device 1 shown in FIG.
As described above, the control terminal 70 individually controls each of the electrophoretic display devices 1. The control terminal 70 includes a timer unit (not shown).

  In the electrophoretic display device 1 shown in FIG. 1, a timer unit (not shown) is provided in the control unit 40, and the application times T1, T2, T3, T4, etc. are managed using this timer unit. It was. However, in the case of a display system including a plurality of electrophoretic display devices 1, if a timer unit is provided in each electrophoretic display device 1, the cost of the entire system is increased. Therefore, in the present embodiment, the control terminal 70 is provided with a timer unit (not shown), and the control terminal 70 manages the application times T1, T2, T3, T4 and the like in each electrophoretic display device 1. .

  In addition, the electrophoretic display device 1 is used not only in a single form like a clock used at home, but also in a plurality of forms like an electronic shelf label such as a supermarket or a convenience store. There is. As described above, when a plurality of electrophoretic display devices 1 are used, if each electrophoretic display panel 10 is controlled by the control device 20 provided corresponding to each electrophoretic display device 1, It becomes complicated. Therefore, in the present embodiment, each electrophoretic display device 1 and the control terminal 70 are connected via a network, and each electrophoretic display panel 10 is managed by the control terminal 70.

  Note that the program for executing the processing as described in the above embodiment may be in the form of a storage medium or a program transmission device. That is, the program to be executed by the computer device can be stored in a storage medium such as a CD-ROM, DVD, memory, or hard disk so that the computer device can read the program. In addition, storage means such as a CD-ROM, DVD, memory, and hard disk that stores the program, and the apparatus that reads the program from the storage means and executes the program via a connector or a network such as the Internet or a LAN A program transmission apparatus including transmission means for transmitting a program can also be provided. In addition to this, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate without departing from the gist of the present invention.

1 is a schematic configuration diagram illustrating an electrophoretic display device according to an embodiment. It is a figure explaining an electrophoretic display panel and a driver. It is a figure for demonstrating operation | movement of an electrophoretic display panel. It is a figure for demonstrating display change operation | movement. The voltage applied to a common electrode and a pixel electrode is shown. The experimental condition in an Example and a comparative example is shown typically. It is explanatory drawing which showed the experimental result in an Example and a comparative example. The voltage application form in 2nd Embodiment and 3rd Embodiment is shown. It is the schematic block diagram which showed the outline of the display system comprised by several electrophoretic display apparatuses.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electrophoretic display apparatus, 10 ... Electrophoretic display panel, 13 ... Common electrode, 14 ... Pixel electrode, 15a ... White particle, 15b ... Black particle, 30 ... Driver, 40 ... Control part, 70 ... Control terminal

Claims (8)

An electrophoretic ink comprising a first electrode and a second electrode disposed at a position opposite to the first electrode, and including at least a dispersion medium and charged particles that move by the action of an electric field, An electrophoretic display panel disposed between the second electrode and the second electrode;
Applying means for applying a voltage to the first electrode and the second electrode of the electrophoretic display panel;
Prior to changing the display of the electrophoretic display panel, a voltage for moving the charged particles toward the one electrode is applied to the first electrode and the second electrode a plurality of times. Control means for controlling the application means to apply a voltage for moving the charged particles toward the other electrode a plurality of times with respect to the electrode and the second electrode,
The control means includes an addition value (first addition value) obtained by adding each of the time integral values obtained by integrating the voltage for moving the charged particles toward one electrode with time, and the charged particles on the other electrode. An electrophoretic display device, wherein an addition value (second addition value) obtained by adding each of time integration values obtained by integrating a voltage for moving toward an electrode with time is made different.   2. The electricity according to claim 1, wherein the control unit makes the first addition value smaller than the second addition value when the charged particles are positioned on the one electrode side. Electrophoretic display device. An electrophoretic ink comprising a first electrode and a second electrode disposed at a position opposite to the first electrode, and including at least a dispersion medium and charged particles that move by the action of an electric field, An electrophoretic display panel disposed between the second electrode and the second electrode;
Applying means for applying a voltage to the first electrode and the second electrode of the electrophoretic display panel;
Prior to changing the display of the electrophoretic display panel, a voltage for moving the charged particles toward one electrode and a voltage for moving the charged particles toward the other electrode are applied a plurality of times. Control means for controlling the application means,
The control means controls the application means so that the position of the charged particles after the plurality of times of application is closer to the electrode toward which the charged particles are directed by the display change than the position of the charged particles before the times of application. An electrophoretic display device characterized by controlling. An electrophoretic ink comprising a first electrode and a second electrode disposed at a position opposite to the first electrode, and including at least a dispersion medium and charged particles that move by the action of an electric field, A control device for controlling an electrophoretic display panel disposed between the second electrode and the second electrode,
Applying means for applying a voltage to the first electrode and the second electrode of the electrophoretic display panel;
Prior to changing the display of the electrophoretic display panel, a voltage for moving the charged particles toward one electrode is applied a plurality of times, and a voltage for moving the charged particles toward the other electrode is applied a plurality of times. Control means for controlling the application means to apply,
The control means includes a voltage application condition (first application condition) for moving the charged particles toward the one electrode, and a voltage condition for moving the charged particles toward the other electrode. A control device characterized by different application conditions (second application conditions).   The control means has at least one of a magnitude and an application time between the voltage applied a plurality of times under the first application condition and the voltage applied a plurality of times under the second application condition. The control device according to claim 4, wherein the control device is made different.   The control means, when the charged particles are located on the one electrode side, makes the number of times of application under the first application condition smaller than the number of times of application under the second application condition. The control device according to claim 5. A first electrode and a second electrode disposed at a position opposite to the first electrode with an electrophoretic ink including at least a charged particle moving by the action of an electric field and a dispersion medium for dispersing the charged particle interposed therebetween A control method for controlling application of voltage to an electrophoretic display panel provided,
Prior to the display change in the electrophoretic display panel, a voltage for moving the charged particles in one direction is applied to the first electrode and the second electrode under a first application condition, A control method characterized by applying a voltage for moving the charged particles in the other direction to the first electrode and the second electrode under a second application condition. A first electrode and a second electrode disposed at a position opposite to the first electrode with an electrophoretic ink including at least a charged particle moving by the action of an electric field and a dispersion medium for dispersing the charged particle interposed therebetween A plurality of display devices each comprising: an electrophoretic display panel provided; and an application unit that applies a voltage to the first electrode and the second electrode of the electrophoretic display panel;
Prior to changing the display in the electrophoretic display panel provided in each of the plurality of display devices, a voltage is applied according to a first application condition to move the charged particles in one direction, and the charged particles are A control terminal for controlling each of the application means to apply a voltage according to a second application condition to move in the other direction;
A display system characterized by comprising:

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