JP2010211223A - Method of driving electrophoretic device, controller for controlling electrophoretic device, electrophoretic device, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of driving an electrophoretic display device, which hardly brings about persistence while suppressing unnecessary power consumption. <P>SOLUTION: The method of driving the electrophoretic device includes: a display area including electrophoretic elements wherein a dispersion system containing electrophoretic particles is interposed between a common electrode and a pixel electrode; a driving means which applies voltages to the electrophoretic elements to drive the electrophoretic elements; and a control means which controls the driving means. The display area includes two or more kinds of display units to be rewritten at different rewrite intervals. When an image is rewritten, the control means controls the driving means to apply a higher voltage to electrophoretic elements included in a display unit having a longer rewrite interval. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for driving an electrophoretic device, an electrophoretic device, an electronic apparatus including the electrophoretic device, an electronic timepiece, and the like.

  When an electric field is applied to a dispersion system in which electrophoretic particles are dispersed in a solution, the phenomenon of electrophoretic particles migrating by Coulomb force (electrophoretic phenomenon) is known. Electrophoretic display using this phenomenon Equipment has been developed.

  In the electrophoretic display device, if the display state is maintained for a long time, the electrophoretic particles are fixed to the electrode or the like, and the movement of the particles becomes slow during rewriting, and an afterimage may remain. For example, when an electrophoretic display device is used for an electronic watch, there are display units with greatly different rewrite intervals such as month display, day display, hour display, minute display, second display, etc. in one display area. Since the display is maintained for about 720 hours and the day display is 24 hours, the afterimage is likely to remain when the display is rewritten.

  Such an afterimage can be suppressed by a method of refreshing display repeatedly at short intervals, a method of applying a high voltage at the time of rewriting, a method of applying a voltage for a long time at the time of rewriting, or the like. Japanese Patent Laying-Open No. 2004-325489 (Patent Document 1) discloses a method of applying a high frequency voltage to a common electrode as a method for solving such a problem.

JP 2004-325489 A

  However, if the afterimage is suppressed by applying a high voltage during rewriting or applying a voltage for a long time, if there are display units with different rewriting times in one display area, such as an electronic watch, Even in a display unit such as a display or a second display in which a rewrite interval is short and an afterimage is relatively difficult to remain, a voltage more than necessary is consumed. Also, if the display is refreshed at the same interval in all display units, the display is refreshed more frequently than necessary in the display unit with a long rewrite interval such as a month display or a day display. Incurs an increase. Further, in the method of applying a high frequency voltage, the drive circuit becomes complicated and the power loss due to the parasitic resistance of the wiring becomes large.

  SUMMARY An advantage of some aspects of the invention is that it provides a method for driving an electrophoretic display device in which afterimages are less likely to remain while suppressing unnecessary power consumption.

  In order to solve the above-described problems, a first aspect of a method for driving an electrophoretic device according to the present invention is an electrophoretic element in which a dispersion system containing electrophoretic particles is interposed between a common electrode and a pixel electrode. Including a display area, a driving means for driving the electrophoretic element by applying a voltage to the electrophoretic element, and a control means for controlling the driving means, the display area having different rewrite intervals. An electrophoretic device driving method including two or more types of display units to be rewritten, wherein when the image is rewritten, the control unit controls the driving unit to include the display unit having a longer rewrite interval. A higher voltage is applied to the electrophoretic element.

  According to such a configuration, for example, a higher voltage is applied to an electrophoretic element included in a display unit having a longer rewrite interval and an afterimage easily remaining, such as month display or day display of an electronic watch. Afterimage can be suppressed. On the other hand, in a display unit with a short rewrite interval such as minute display and second display, it is possible to suppress consumption of unnecessary power. In addition, when a higher voltage is applied, the electrophoretic particles are more densely collected on the electrode, so that it is possible to maintain a good display for a long time in a display unit having a long rewrite interval.

  In addition, a second aspect of the method for driving an electrophoretic device according to the present invention for solving the above-described problem is an electric device in which a dispersion system containing electrophoretic particles is interposed between a common electrode and a pixel electrode. A display area including an electrophoretic element; drive means for driving the electrophoretic element by applying a voltage to the electrophoretic element; and control means for controlling the drive means, wherein different rewrites are provided in the display area. An electrophoretic device driving method including two or more types of display units rewritten at intervals, wherein when the image is rewritten, the control unit controls the driving unit so that the display unit having a longer rewriting interval is used. A voltage for a longer time is applied to the electrophoretic element included in the apparatus.

  Even with such a configuration, the afterimage can be suppressed by controlling the application of the voltage for a longer time to the electrophoretic element included in the display unit having the longer rewrite interval and the afterimage is likely to remain. On the other hand, in a display unit with a short rewrite interval such as minute display and second display, it is possible to suppress consumption of unnecessary power. Further, when a voltage is applied for a longer time, the electrophoretic particles are more densely collected on the electrode, so that it is possible to maintain a good display for a long time in a display unit having a long rewrite interval.

  In the method for driving the electrophoretic device, the voltage is divided and applied in a plurality of pulses, and the number of pulses is increased, so that an electrophoretic element included in a display unit with a longer rewrite interval can be used for a longer time. It is also preferable to control to apply a voltage. According to such a configuration, it is possible to apply different time voltages to the respective electrophoretic elements with a simple circuit.

  Note that a method of applying a higher voltage to an electrophoretic element included in a display unit having a longer rewrite time and controlling the application time of the voltage to be longer is also included in the present invention.

  The third aspect of the electrophoretic device according to the present invention for solving the above-described problems is an electrophoretic element comprising a dispersion system containing electrophoretic particles interposed between a common electrode and a pixel electrode. Including a display area, driving means for driving the electrophoretic element by applying a voltage to the electrophoretic element, and control means for controlling the driving means, and the display area is rewritten at different rewrite intervals. A method of driving an electrophoretic device including two or more types of display units, wherein the control unit controls the driving unit so that the rewrite interval is included in the display unit longer than a predetermined time. A voltage is applied only to the element to refresh the display in the display unit.

  Here, “refreshing display” means that the distribution state of the electrophoretic particles distributed once so as to display a desired image by applying a voltage is stabilized or maintained regularly or irregularly. A voltage is applied based on image data. Therefore, unlike the “refresh” which is conventionally performed by erasing and writing data in a liquid crystal display device, the present invention does not necessarily require erasing data.

  Even with such a configuration, the afterimage can be suppressed by refreshing the display only in the display unit in which the rewrite interval is longer than the predetermined time and the afterimage is likely to remain. Note that the display refresh interval may be constant for all display units in which the rewrite interval is longer than a predetermined time, or may be different for each display unit. On the other hand, in a display unit with a short rewrite interval such as minute display or second display, it is possible to suppress unnecessary power consumption without performing refresh.

  In the driving method of the electrophoretic device, it is also preferable that display refresh is repeatedly performed and the refresh interval of the display is set to be shorter than a time during which the display holding performance of the dispersion system is lowered to an allowable limit. With such a configuration, display performance is always maintained within an allowable range. Note that if the display refresh interval is set slightly shorter than the time during which the display retention performance of the distributed system falls to the allowable limit, the number of refreshes can be minimized, and unnecessary power is consumed. Can be prevented.

  Further, in the driving method of the electrophoretic device, display refresh is repeatedly performed, and the display holding performance of the dispersion system does not decrease to an allowable limit until the next display refresh in each refresh of the display. Thus, it is preferable to apply a sufficiently high voltage. With such a configuration, the display performance is always kept within an allowable range. Note that if the applied voltage is set to the minimum as long as the display performance does not drop to an allowable limit before the next display refresh, unnecessary power consumption can be prevented.

  Further, in the driving method of the electrophoretic device, display refresh is repeatedly performed, and the display holding performance of the dispersion system does not decrease to an allowable limit until the next display refresh in each refresh of the display. Thus, it is also preferable to apply a voltage for a sufficiently long time. Even with such a configuration, the display performance is always maintained within the allowable range. It should be noted that if the voltage application time is set to the shortest as long as the display performance does not drop to an allowable limit before the next display refresh, unnecessary power consumption can be prevented.

  Furthermore, this invention also includes the following electrophoresis apparatuses as an electrophoresis apparatus which solves the said subject.

  A first aspect of the electrophoretic device according to the present invention includes a display region including an electrophoretic element in which a dispersion system containing electrophoretic particles is interposed between a common electrode and a pixel electrode, and the electrophoretic element. A driving unit that drives the electrophoretic element by applying a voltage; and a control unit that controls the driving unit. The display area includes two or more display units that are rewritten at different rewriting intervals. When rewriting, the control unit controls the driving unit so that a higher voltage is applied to the electrophoretic element included in the display unit having a longer rewriting interval. And

  According to such a configuration, for example, in the case of an electronic timepiece, control is performed so that a higher voltage is applied to the electrophoretic element included in the display unit having a longer rewriting interval such as a month display or a day display and in which an afterimage tends to remain. Thus, afterimages can be suppressed. On the other hand, in a display unit with a short rewrite interval such as minute display and second display, it is possible to suppress consumption of unnecessary power. Furthermore, when a higher voltage is applied, the electrophoretic particles are more densely integrated on the electrode, so that an effect that a good display can be maintained for a long time can be obtained.

  The second aspect of the electrophoretic device according to the present invention for solving the above-described problem is that an electrophoretic element comprising a dispersion system containing electrophoretic particles interposed between a common electrode and a pixel electrode is provided. Including a display area, a drive unit that drives the electrophoretic element by applying a voltage to the electrophoretic element, and a control unit that controls the drive unit, and the display area has different rewrite intervals. Two or more types of display units to be rewritten are included, and when performing rewriting, the control unit controls the driving unit, whereby the electrophoretic element included in the display unit having a longer rewriting interval is included in the electrophoretic element. The voltage is applied for a longer time.

  Even with such a configuration, the afterimage can be suppressed by controlling the application of the voltage for a longer time to the electrophoretic element included in the display unit having the longer rewrite interval and the afterimage is likely to remain. On the other hand, in a display unit with a short rewrite interval such as minute display and second display, it is possible to suppress consumption of unnecessary power. Further, when a voltage is applied for a longer time, the electrophoretic particles are more densely collected on the electrode, so that it is possible to maintain a good display for a long time.

  In addition, when a voltage is applied for a longer time, the width of the drive pulse (voltage application time) may be increased, or the voltage may be applied by dividing it into a plurality of pulses and increasing the number of pulses. The total time may be lengthened.

  Note that an apparatus controlled so as to apply a higher voltage to an electrophoretic element included in a display unit having a longer rewrite time and to extend the application time of the voltage is also included in the present invention. .

  The third aspect of the electrophoretic device according to the present invention for solving the above-described problems is an electrophoretic element comprising a dispersion system containing electrophoretic particles interposed between a common electrode and a pixel electrode. Including a display area, a drive unit that drives the electrophoretic element by applying a voltage to the electrophoretic element, and a control unit that controls the drive unit, and the display area has different rewrite intervals. Two or more types of display units to be rewritten are included, and when the control unit controls the driving unit, a voltage is applied only to the electrophoretic element included in the display unit in which the rewrite interval is longer than a predetermined time. The display is refreshed in the display unit when applied.

  Here, “refreshing display” means that the distribution state of the electrophoretic particles distributed once so as to display a desired image by applying a voltage is stabilized or maintained regularly or irregularly. A voltage is applied based on image data. Therefore, unlike the “refresh” which is conventionally performed by erasing and writing data in a liquid crystal display device, the present invention does not necessarily require erasing data.

  Even with such a configuration, the afterimage can be suppressed by refreshing the display only in the display unit in which the rewrite interval is longer than the predetermined time and the afterimage is likely to remain. Note that the display refresh interval may be constant for all display units in which the rewrite interval is longer than a predetermined time, or may be different for each display unit. On the other hand, in a display unit with a short rewrite interval such as minute display or second display, it is possible to suppress unnecessary power consumption without performing refresh.

  In the electrophoretic device according to the present invention, it is preferable that display refresh is repeatedly performed, and the display refresh interval is set shorter than a time during which the display holding performance of the dispersion system falls to an allowable limit. . With such a configuration, display performance is always maintained within an allowable range. Note that if the display refresh interval is set slightly shorter than the time during which the display retention performance of the distributed system falls to the allowable limit, the number of refreshes can be minimized, and unnecessary power is consumed. Can be prevented.

  Further, in the electrophoresis apparatus according to the present invention, display refresh is repeatedly performed, and each time the display is refreshed, the display holding performance of the dispersion system is reduced to an allowable limit until the next display refresh. It is also preferred that a sufficiently high voltage is applied so as not to. With such a configuration, the display performance is always kept within an allowable range. Note that if the applied voltage is set to the minimum as long as the display performance does not drop to an allowable limit before the next display refresh, unnecessary power consumption can be prevented.

  Further, in the electrophoresis apparatus according to the present invention, display refresh is repeatedly performed, and each time the display is refreshed, the display holding performance of the dispersion system is reduced to an allowable limit until the next display refresh. It is also preferred that the voltage be applied for a sufficiently long time so that it does not. With such a configuration, the display performance is always kept within an allowable range. It should be noted that if the voltage application time is set to the shortest as long as the display performance does not drop to an allowable limit before the next display refresh, unnecessary power consumption can be prevented.

  In addition, an electronic apparatus according to the present invention includes the above-described electrophoresis apparatus as a display unit. Here, the “electronic device” includes all devices including a display unit that uses display by an electrophoretic material, and includes a display device, a television device, electronic paper, a clock, a calculator, a mobile phone, a portable information terminal, and the like. Including. Also, things that deviate from the concept of “equipment”, for example, flexible paper / film-like objects, belonging to real estate such as wall surfaces to which these objects are attached, moving objects such as vehicles, flying objects, ships, etc. Including those belonging to.

  The electronic timepiece of the present invention includes the above-described electrophoresis apparatus as a display unit, and two or more types of display units are selected from the group consisting of month display, day display, hour display, minute display, and second display. . This electronic timepiece can suppress afterimages efficiently without wasting power even if the electronic timepiece has display units with greatly different rewrite intervals.

1 shows an electronic timepiece in which an electrophoresis apparatus according to the present invention is used. It is a block diagram explaining the circuit structure of the electrophoresis apparatus which concerns on this invention. It is a circuit diagram explaining the structure of each pixel circuit of the electrophoresis apparatus which concerns on this invention. It is a schematic cross section explaining the structural example of an electrophoretic element. It is a wave form diagram explaining an example of the drive method of the electrophoresis apparatus which concerns on this invention. It is a wave form diagram explaining an example of the drive method of the electrophoresis apparatus which concerns on this invention. It is a wave form diagram explaining an example of the drive method of the electrophoresis apparatus which concerns on this invention. It is a figure explaining an example of a time-dependent change of the display holding | maintenance performance of an electrophoresis apparatus. It is an example of the electronic device in which the electrophoresis apparatus according to the present invention is used.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an electronic timepiece 1 as an example of an electronic apparatus using the electrophoresis apparatus according to the present invention. The electrophoretic device provided in the electronic timepiece 1 is driven according to the driving method of the electrophoretic device according to the present invention. As shown in the figure, the electronic timepiece 1 includes a display area 16 including five types of display units of a month display 11, a day display 12, an hour display 13, a minute display 14, and a second display 15. The month 26th, 10:38:45 is displayed.

  FIG. 2 is a block diagram schematically illustrating the circuit configuration of the electrophoretic device 2 included in the electronic timepiece 1. The electrophoretic device 2 includes a controller 21, a display area 16, a scanning line driving circuit 23, and a data line driving circuit 24.

  The controller 21 controls the scanning line driving circuit 23 and the data line driving circuit 24, and includes an image signal processing circuit, a timing generator, etc. (not shown). The controller 21 generates an image signal (image data) indicating an image to be displayed on the display area 16, reset data for performing reset at the time of image rewriting, and other various signals (clock signal and the like), and the scanning line driving circuit 23. Alternatively, the data is output to the data line driving circuit 24.

  The display area 16 includes a plurality of data lines arranged in parallel along the X direction, a plurality of scanning lines arranged in parallel along the Y direction, and intersections of these data lines and scanning lines. The pixel circuit is arranged, and an image is displayed by the electrophoretic element included in each pixel circuit.

  The scanning line driving circuit 23 is connected to each scanning line in the display area 16, selects any one of these scanning lines, and applies predetermined scanning line signals Y1, Y2,..., Ym to the selected scanning line. Supply. These scanning line signals Y1, Y2,..., Ym are signals for sequentially shifting the active period (H level period), and are output to each scanning line, so that the pixel circuits connected to each scanning line Sequentially turned on.

  The data line driving circuit 24 is connected to each data line in the display area 16 and supplies data signals X1, X2,..., Xn to each pixel circuit selected by the scanning line driving circuit 23.

  The controller 21 described above corresponds to “control means” in the present invention, and the scanning line drive circuit 23 and the data line drive circuit 24 correspond to “drive means” in the present invention.

  FIG. 3 is a circuit diagram illustrating the configuration of each pixel circuit. The pixel circuit shown in FIG. 3 includes a switching transistor 31, an electrophoretic element 32, and a storage capacitor 33. The transistor 31 is an N-channel transistor, for example, and has a gate connected to the scanning line 34, a source connected to the data line 35, and a drain connected to the pixel electrode of the electrophoretic element 32. The electrophoretic element 32 is configured by interposing a dispersion system between the common electrode and the pixel electrode. The holding capacitor 33 is connected in parallel with the electrophoretic element 32.

  FIG. 4 is a schematic cross-sectional view illustrating a configuration example of the electrophoretic element. As shown in FIG. 4, the electrophoretic element 32 of this embodiment includes a pixel electrode 43 formed on a substrate 41 made of glass or resin, and a common electrode 44 formed on a substrate 42 made of glass or resin. And a dispersion system 45 containing electrophoretic particles 46 and 47 is interposed therebetween. In the present embodiment, the electrophoretic particles 46 are electrically negatively charged white particles (white particles), and the electrophoretic particles 47 are electrically positively charged black particles (black particles). To do. By controlling the voltage applied between the pixel electrode 43 and the common electrode 44, the spatial arrangement of the electrophoretic particles 46 and 47 changes, and white or black is displayed.

  In such an electrophoretic element 32, for example, a low power supply potential Vss (for example, 0 V) is applied to the pixel electrode via a data line, and a high power supply potential Vdd (for example, +10 V) is used as the common electrode potential (common potential) Vcom. When the white particles 46 move to the common electrode side 44 and the black particles 47 move to the pixel electrode 43 side and are observed from the common electrode 44 side (from the lower side in the figure), white is displayed. On the other hand, when Vss is applied as the common potential Vcom and Vdd is applied to the pixel electrode, the black particles 47 move to the common electrode 44 side, and the white particles 46 move to the pixel electrode 43 side. White color is displayed.

  Next, a specific driving method of the electrophoretic device 2 provided in the electronic timepiece 1 according to the present invention will be described. In the electrophoretic device 2 of the present embodiment, in order to rewrite an image, the controller 21 controls the scanning line driving circuit 23 and the data line driving circuit 24 so that the common electrode 44 and the pixel electrode 43 of each electrophoretic element 32 are controlled. Apply voltage to The controller 21 independently controls the voltage applied to the electrophoretic element 32 included in each display unit of the month display 11, the day display 12, the hour display 13, the minute display 14, and the second display 15 for each display unit. can do.

  FIG. 5 is a waveform diagram for explaining a driving method of one embodiment of the electronic timepiece 1 according to the present invention.

As shown in FIG. 5 (A), the controller 21 applies a voltage to the month display 11 by controlling the scanning line driving circuit 23 and the data line driving circuit 24 for rewriting the display every month. Change the display. In this case, it represents the voltage applied between V _M. Similarly, a voltage for rewriting the display is applied to the date display 12 every 24 hours, and the voltage applied at this time is V _D. Further, a voltage for rewriting the display is applied to the hour display 13 every hour, the voltage applied at this time is set to V _H, and the voltage applied to the minute display 14 is applied every minute, and the voltage applied at this time is set to V _{H The} voltage is applied every second in the second 15 display, and the voltage applied at this time is expressed as V _S.

Then, the controller 21 applies a higher voltage to the electrophoretic element 32 included in a display unit having a longer rewrite interval, such as the month display 11 or the day display 12, and the scanning line driving circuit 23 and the data line driving circuit 24. To control. That is, the applied voltage is controlled so that V _M ≧ V _D ≧ V _H ≧ V _min ≧ V _S. As long as V _M ≧ V _D ≧ V _H ≧ V _min ≧ V _S is satisfied, the magnitude of each voltage is not particularly limited, and may satisfy V _M > V _D > V _H > V _min > V _S. V _M = V _D > V _H > V _min = V _S or the like may be used.

  By controlling in this way, a high voltage is applied to a display unit with a long rewrite interval and an afterimage that tends to remain, and even if the electrophoretic particles are fixed to an electrode or the like, it is moved and the afterimage is left without leaving an afterimage. Images can be displayed. Further, by applying a high voltage at the time of rewriting, the electrophoretic particles are densely deposited on the electrode, so that it is possible to maintain an excellent display for a long time without refreshing the display. . On the other hand, for a display unit such as the minute display 14 or the second display 15 that does not need to hold the display for a long time and the electrophoretic particles are not easily fixed, a voltage that is low enough to rewrite the display is applied to reduce the power consumption. Can be reduced.

  FIG. 6 is a waveform diagram for explaining a driving method of another embodiment of the electronic timepiece 1 according to the present invention.

The controller 21 controls the scanning line driving circuit 23 and the data line driving circuit 24 so that the month display 11 is displayed every month, the day display 12 is displayed every 24 hours, and the hour display 13 is displayed every hour. The voltage is applied so that the voltage application time becomes V _LM , V _LD , V _LH , V _Lmin , and V _LS every minute on the minute display 14 and every second on the second display 15.

Then, the controller 21 increases the voltage application time to the electrophoretic element 32 included in a display unit having a longer rewrite interval such as the month display 11 or the day display 12. That is, control is performed so that V _LM ≧ V _LD ≧ V _LH ≧ V _Lmin ≧ V _LS . As long as the expression V _LM ≧ V _LD ≧ V _LH ≧ V _Lmin ≧ V _LS is satisfied, the magnitude of each voltage is not particularly limited, and may be V _LM > V _LD > V _LH > V _Lmin > V _LS V _LM = V _LD > V _LH > V _Lmin = V _LS or the like may be used.

  By controlling in this way, a voltage is applied to a display unit with a long rewrite interval and an afterimage is likely to remain, and even if the electrophoretic particles are fixed to an electrode or the like, it is moved and no afterimage is left. The next image can be displayed. In addition, by applying a voltage for a long time at the time of rewriting, the electrophoretic particles are densely deposited on the electrode, so that an excellent display can be maintained for a long time without refreshing the display. It is done. On the other hand, it is not necessary to keep the display for a long time such as the minute display 14 and the second display 15 and the application of the voltage to the display unit where the electrophoretic particles are hardly fixed can be applied for a short time to reduce the power consumption.

  When a voltage is applied for a longer time, the width of the drive pulse may be changed as shown in FIG. 6, or it is divided into a plurality of pulses and applied to increase the number of pulses as shown in FIG. By doing so, the voltage application time may be lengthened. When the length of a single pulse is made variable, it is necessary to provide a timer for measuring time in the controller 21 and an analog circuit such as a D / A converter, but a method for making the number of fixed-width pulses variable. If so, it is only necessary to count the number of pulses, and the circuit can be simplified because it can be constituted by only a digital circuit.

  Further, the present invention includes applying a higher voltage to a display unit having a long rewrite interval and extending the voltage application time.

  In another embodiment of the electronic timepiece 1 according to the present invention, the controller 21 applies a voltage only to the electrophoretic element included in the display unit whose rewrite interval is longer than a predetermined time, and periodically or irregularly in the display unit. Refresh the display. For example, if the predetermined time is 12 hours, the display is refreshed only in the month display 11 and the day display 12. The display refresh may be performed once or repeatedly, may be performed simultaneously in the month display 11 and the day display 12, or may be performed at different timings.

  When the display refresh is repeated, the display refresh interval can be determined in consideration of the display holding performance of the electrophoretic dispersion system to be used and the desired display quality (allowable quality). Specifically, the display refresh interval can be set shorter than the time during which the display holding performance of the electrophoretic dispersion system included in the electronic timepiece 1 is reduced to an allowable limit. For example, it is assumed that the display holding performance of the electrophoretic dispersion system included in the electronic timepiece 1 is represented by the contrast relative value shown in FIG. At this time, from the graph shown in FIG. 8, it is calculated that the contrast relative value decreases by 20% after about 1 hour. Therefore, if the display refresh interval is less than 1 hour, the display holding performance is always within the allowable range. Can be maintained within.

  Further, as described above, when the display refresh interval is determined by obtaining the time during which the display holding performance falls to the allowable limit, it is preferable that the time is slightly shorter than the obtained time. If the display is refreshed at an interval slightly shorter than the required time, the display performance is always maintained within the allowable range, and at the same time, the number of display refreshes can be minimized. This is because it can be prevented from being consumed more than necessary.

  In general, since the display holding performance of the electrophoretic dispersion system changes with time, the refresh interval of the display may be determined in consideration of the change. In such a configuration, for example, the controller 21 processes the display holding performance information, obtains a time for the display holding performance to fall to an allowable limit from the information, determines a display refresh interval based on the time, This is realized by applying a voltage to the electrophoretic element.

  On the other hand, the display refresh interval is kept constant regardless of the degradation rate of the display retention performance of the dispersion system, and a high voltage is applied so that the display retention performance does not decrease to an allowable limit until the next refresh, The voltage application time may be lengthened. For example, if refreshing is performed every hour, it is sufficient to apply a voltage large enough to hold the display for one hour. In this case as well, power is necessary while maintaining the display holding performance within the allowable range by setting the applied voltage to a value that recovers just the performance that drops in 1 hour or recovers it slightly. It can prevent being consumed more. In this case as well, changes with time in the display holding performance of the dispersion system may be taken into consideration.

  The electrophoretic device and the driving method thereof according to the present invention have been described by taking the electronic timepiece 1 as an example. However, the electrophoretic device and the driving method according to the present invention are not limited to the electronic timepiece 1, For example, the following electronic devices can be preferably used when a display with a different rewrite interval, such as a clock display, is included.

  FIG. 9 is a perspective view illustrating a specific example of an electronic apparatus to which the electrophoresis apparatus is applied. FIG. 9A is a perspective view illustrating an electronic book that is an example of the electronic apparatus. The electronic book 1000 includes a book-shaped frame 1001, a cover 1002 provided to be rotatable (openable and closable) with respect to the frame 1001, an operation unit 1003, and the electrophoresis apparatus according to the present embodiment. The display unit 1004 is provided. FIG. 9A is a perspective view illustrating an electronic book that is an example of the electronic apparatus. The electronic book 1000 includes a book-shaped frame 1001, a cover 502 that can be rotated (openable and closable) with respect to the frame 1001, an operation unit 1003, and the electrophoresis apparatus according to the present embodiment. The display unit 1004 is provided. FIG. 9B is a perspective view illustrating electronic paper which is an example of the electronic apparatus. The electronic paper 1200 includes a main body unit 1201 configured by a rewritable sheet having the same texture and flexibility as paper, and a display unit 1202 configured by the electrophoresis apparatus according to the present embodiment. The range of electronic devices to which the electrophoretic device can be applied is not limited to this, and includes a wide range of devices that utilize changes in visual color tone accompanying the movement of charged particles. For example, in addition to the above-described devices, those belonging to real estate such as wall surfaces to which an electrophoretic film is bonded, and those belonging to moving bodies such as vehicles, flying objects, and ships are also applicable.

  In addition, this invention is not limited to the content of embodiment mentioned above, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above description, the active matrix type is described as an example of the circuit configuration of the electrophoresis apparatus, but the present invention is not limited to this circuit configuration. For example, even in a passive matrix circuit configuration or a so-called segment direct drive type circuit configuration in which a drive voltage is individually applied to each pixel electrode from a controller, the driving method of the present invention Can be applied.

DESCRIPTION OF SYMBOLS 1 ... Electronic clock, 11 ... Month display, 12 ... Day display, 13 ... Hour display, 14 ... Minute display, 15 ... Second display, 16 ... Display area, 2 ... Electrophoresis device, 21 ... Controller, 23 ... Scan line drive Circuit 24, data line driving circuit 31, transistor 32, electrophoretic element 33, holding capacitor 34, scanning line 35, data line 41, 42, substrate 43, pixel electrode 44, common electrode 45 ... electrophoretic dispersion system, 46, 47 ... electrophoretic particles

Claims (16)

A display region including an electrophoretic element in which a dispersion system containing electrophoretic particles is interposed between a common electrode and a pixel electrode; and driving means for driving the electrophoretic element by applying a voltage to the electrophoretic element And a control means for controlling the drive means, wherein the display area includes two or more types of display units that are rewritten at different rewrite intervals.
When performing image rewriting, the control unit controls the driving unit to apply a higher voltage to the electrophoretic element included in the display unit having a longer rewriting interval. . A display region including an electrophoretic element in which a dispersion system containing electrophoretic particles is interposed between a common electrode and a pixel electrode; and driving means for driving the electrophoretic element by applying a voltage to the electrophoretic element And a control means for controlling the drive means, wherein the display area includes two or more types of display units that are rewritten at different rewrite intervals.
When performing image rewriting, the control unit controls the driving unit to apply a voltage for a longer time to the electrophoretic element included in the display unit having a longer rewriting interval. Method.   3. The voltage is applied to the electrophoretic element included in the display unit having a longer rewrite interval by applying the voltage divided into a plurality of pulses and increasing the number of pulses. A driving method of the electrophoresis apparatus according to claim 1. A display region including an electrophoretic element in which a dispersion system containing electrophoretic particles is interposed between a common electrode and a pixel electrode; and driving means for driving the electrophoretic element by applying a voltage to the electrophoretic element And a control means for controlling the drive means, wherein the display area includes two or more display units that are rewritten at different rewrite intervals,
The control unit controls the driving unit to apply a voltage only to the electrophoretic element included in the display unit in which the rewrite interval is longer than a predetermined time, and refresh the display in the display unit. Driving method of electrophoresis apparatus. The display refresh is repeated, and the refresh interval of the display is
The method for driving an electrophoretic device according to claim 4, wherein the display holding performance of the dispersion system is set to be shorter than the time required for the display system to fall to an allowable limit.   The display is refreshed repeatedly, and at each display refresh, a sufficiently high voltage is applied so that the display holding performance of the dispersion system does not decrease to an allowable limit before the next display refresh. The method for driving an electrophoretic device according to claim 4.   The display is repeatedly refreshed, and a voltage is applied for a sufficiently long time so that the display holding performance of the distributed system does not decrease to an allowable limit before the next display refresh. The method for driving an electrophoretic device according to claim 4. A display region including an electrophoretic element in which a dispersion containing electrophoretic particles is interposed between a common electrode and a pixel electrode;
Drive means for driving the electrophoretic element by applying a voltage to the electrophoretic element;
Control means for controlling the drive means,
The display area includes two or more display units that can be rewritten at different rewriting intervals.
When performing rewriting, the control means controls the driving means so that a higher voltage is applied to the electrophoretic element included in the display unit having a longer rewriting interval. A display region including an electrophoretic element in which a dispersion containing electrophoretic particles is interposed between a common electrode and a pixel electrode;
Drive means for driving the electrophoretic element by applying a voltage to the electrophoretic element;
Control means for controlling the drive means,
The display area includes two or more display units that can be rewritten at different rewriting intervals.
When performing rewriting, the control unit controls the driving unit to apply a voltage for a longer time to the electrophoretic element included in the display unit having a longer rewriting interval.   The voltage is applied by being divided into a plurality of pulses, and by increasing the number of pulses, a longer time voltage is applied to the electrophoretic element included in the display unit having a longer rewrite interval. Item 10. The electrophoresis apparatus according to Item 9. A display region including an electrophoretic element in which a dispersion containing electrophoretic particles is interposed between a common electrode and a pixel electrode;
Drive means for driving the electrophoretic element by applying a voltage to the electrophoretic element;
Control means for controlling the drive means,
The display area includes two or more display units that can be rewritten at different rewriting intervals.
When the control unit controls the driving unit, a voltage is applied only to the electrophoretic element included in the display unit in which the rewrite interval is longer than a predetermined time, and display is refreshed in the display unit. Electrophoresis device. The display refresh is repeated, and the refresh interval of the display is
The electrophoretic device according to claim 11, wherein the display holding performance of the dispersion system is set to be shorter than a time required for the dispersion system to fall to an allowable limit. The display refresh is repeated, and at each refresh of the display,
The electrophoretic device according to claim 11, wherein a sufficiently high voltage is applied so that the display holding performance of the dispersion system does not decrease to an allowable limit before the next display refresh. The display refresh is repeated, and at each refresh of the display,
The electrophoretic device according to claim 11, wherein a voltage is applied for a sufficiently long time so that the display holding performance of the dispersion system does not decrease to an allowable limit before the next display refresh.   An electronic device comprising the electrophoresis device according to claim 8.   The electrophoresis apparatus according to claim 8, wherein the two or more types of display units are selected from the group consisting of a month display, a day display, an hour display, a minute display, and a second display. Electronic clock.

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