JP5540880B2 - Electrophoretic display device driving method, electrophoretic display device, and electronic apparatus - Google Patents

Description

  The present invention relates to an electrophoretic display device driving method, an electrophoretic display device, and a technical field of an electronic apparatus including the electrophoretic display device.

  In this type of electrophoretic display device, an image is generated by moving the electrophoretic particles by applying a potential difference between the pixel electrode and the common electrode provided on each of the pair of substrates sandwiching the electrophoretic element including the electrophoretic particles. Is displayed. The electrophoretic element includes, for example, black particles and white particles, and each of these two types of particles is attracted to the common electrode side, whereby two gradations of black or white are displayed.

  When driving the above-described electrophoretic display device, it is required that the DC balance ratio (that is, the ratio of the voltage application time for white and black display) is not destroyed. For this reason, for example, Patent Document 1 proposes a technique of driving so that the net DC voltage is substantially zero after image transition.

JP 2007-512571 A

  However, in the driving method according to Patent Document 1, for example, when white display is performed, black display is always performed after that, so that black and white display is alternately switched in a short time. Such switching of images in a short time may cause flickering and the like, and may cause discomfort to the user of the apparatus. As described above, the above-described technique has a technical problem that even if it can be driven so as not to break the DC balance, a display defect such as flickering occurs.

  The present invention has been made in view of the above-described problems, for example, and provides an electrophoretic display device driving method, an electrophoretic display device, and an electronic apparatus capable of suitably adjusting a DC balance ratio. Let it be an issue.

  In order to solve the above problems, a driving method for an electrophoretic display device according to the present invention is a driving method for an electrophoretic display device in which an electrophoretic element including electrophoretic particles is provided between a pixel electrode and a common electrode facing each other. A display step of applying a first voltage corresponding to a first color and a second voltage corresponding to a second color between the pixel electrode and the common electrode; and the first voltage applied in the display step. An adjustment step of applying an adjustment voltage every predetermined period so that the integration step of integrating one voltage and the second voltage and the ratio of the first voltage and the second voltage integrated in the integration step are the same. A process.

  According to the driving method of the electrophoretic display device of the present invention, for example, electrophoresis in which an electrophoretic element is sandwiched between an element substrate provided with a pixel electrode for each pixel and a counter substrate provided with a common electrode. The display device is driven. The electrophoretic element includes, for example, electrophoretic particles corresponding to the first color and the second color, and each particle is attracted to a common electrode located on the display surface side, so that a color corresponding to each particle is obtained. Can be displayed.

  In the present invention, first, a first voltage corresponding to the first color and a second voltage corresponding to the second color are applied between the pixel electrode and the common electrode. That is, the first voltage is applied to the pixel that should display the first color, and the second voltage is applied to the pixel that should display the second color. Thereby, an image composed of the first color and the second color is displayed on the display unit of the electrophoretic display device.

  In the present invention, the first voltage and the second voltage applied between the pixel electrode and the common electrode are integrated. Specifically, it is stored how long the first voltage and the second voltage are applied. That is, the DC balance ratio is detected.

  When the DC balance ratio is lost, various inconveniences on display occur. The reason for this is that the inventor of the present application causes an electrochemical reaction when ions flow in a state where ions in the solvent of the electrophoretic element are unevenly distributed near an electrode having the opposite polarity to the ions. It is presumed that the electrode, the electrophoretic element, etc. are deteriorated and affect the migration of the electrophoretic particles.

  Here, in the present invention, in particular, the adjustment voltage is applied so that the ratio of the integrated first voltage and second voltage (that is, the DC balance ratio) is the same. For example, when the first voltage is applied for a longer period than the second voltage, the adjustment voltage is applied as a voltage having the same polarity as the second voltage. On the other hand, when the second voltage is applied for a longer period than the first voltage, a voltage having the same polarity as the first voltage is applied as the adjustment voltage. As a result, the DC balance ratio is adjusted to be the same. Therefore, various inconveniences due to the collapse of the DC balance ratio can be prevented.

  Note that “same” here does not only indicate that the DC balance ratio is completely the same (ie, 50:50), but is close enough to say that the DC balance ratios are the same. Means state. That is, even if the DC balance ratios are not completely the same, the effects of the present invention can be obtained correspondingly if the adjustment voltages that are close to each other are applied.

  Furthermore, in the present invention, the above-described adjustment voltage is applied collectively at predetermined intervals. Here, the “predetermined period” is a period for determining the frequency of applying the adjustment voltage, and is set in advance by deriving experimentally, theoretically or empirically.

  If an adjustment voltage is applied every time an image is rewritten, images with different gradations are alternately displayed in a short time, and flickering occurs. On the other hand, if the adjustment voltage is applied together every predetermined period, the image switching frequency can be greatly reduced. Therefore, flicker can be prevented. In other words, the predetermined period of the present invention is set as a period that is long enough to prevent flickering. However, from the viewpoint of not destroying the DC balance ratio, it is preferable that the predetermined period is shorter. According to the research of the present inventor, for example, by setting the predetermined period to 60 seconds or more, it has been found that the DC balance ratio can be maintained to such an extent that the flicker is suitably prevented and no malfunction occurs.

  As described above, according to the driving method of the electrophoretic display device of the present invention, it is possible to suitably adjust the DC balance ratio while suppressing the occurrence of flicker.

  In one aspect of the driving method of the electrophoretic display device of the present invention, in the adjustment step, the adjustment voltage is set to a predetermined voltage, and a time corresponding to a ratio of the first voltage and the second voltage integrated in the integration step. Only applied.

  According to this aspect, the DC balance ratio is maintained by adjusting the application time of the adjustment voltage. That is, when the DC balance ratio is greatly broken, a relatively long time adjustment voltage is applied, and when the DC balance is not greatly broken, a relatively short time adjustment voltage is applied. In this way, it is possible to adjust the DC balance ratio very easily.

  In another aspect of the method for driving an electrophoretic display device of the present invention, in the adjustment step, the adjustment voltage is a voltage corresponding to a ratio of the first voltage and the second voltage integrated in the integration step. Applied for a predetermined time.

  According to this aspect, the DC balance ratio is maintained by adjusting the voltage value of the adjustment voltage. In other words, when the DC balance ratio is greatly broken, a relatively high adjustment voltage is applied, and when the DC balance is not greatly broken, a relatively low adjustment voltage is applied. In this way, it is possible to adjust the DC balance ratio very easily.

  Note that the DC balance ratio can also be suitably adjusted by using the adjustment based on the voltage value and the adjustment based on the application time described above in combination.

  In another aspect of the driving method of the electrophoretic display device of the present invention, the electrophoretic display device includes a temperature detection step of detecting the temperature of the electrophoretic element, and the adjustment voltage is applied based on the temperature of the electrophoretic element in the adjustment step. Is done.

  According to this aspect, the temperature of the electrophoretic element when the voltage is applied is detected. The temperature of the electrophoretic element may be detected directly from the electrophoretic element, or may be indirectly detected from, for example, a pixel electrode, a common electrode, or other members.

  In this embodiment, in particular, the adjustment voltage is applied based on the detected temperature of the electrophoretic element. That is, the application time or voltage value of the adjustment voltage is changed based on the temperature of the electrophoretic element. Specifically, when the temperature of the electrophoretic element is relatively low, the application time of the adjustment voltage is increased or the voltage value is increased. On the other hand, when the temperature of the electrophoretic element is relatively high, the application time of the adjustment voltage is shortened or the voltage value is lowered. In this way, the adjustment voltage can be applied in consideration of the influence of the temperature on the electrophoretic element, so that the DC balance ratio can be adjusted very suitably.

  In order to solve the above problems, an electrophoretic display device of the present invention includes a pixel electrode and a common electrode facing each other, an electrophoretic element including electrophoretic particles provided between the pixel electrode and the common electrode, and the pixel. Display means for applying a first voltage corresponding to a first color and a second voltage corresponding to a second color between the electrode and the common electrode; the first voltage applied by the display means; 2 includes an integrating unit that integrates two voltages, and an adjusting unit that applies an adjustment voltage every predetermined period so that a ratio between the first voltage and the second voltage integrated by the integrating unit is the same.

  In the electrophoretic display device of the present invention, for example, an electrophoretic element is sandwiched between an element substrate provided with a pixel electrode for each pixel and a counter substrate provided with a common electrode. The electrophoretic element includes, for example, electrophoretic particles corresponding to the first color and the second color, and each particle is attracted to a common electrode located on the display surface side, so that a color corresponding to each particle is obtained. Can be displayed.

  In the present invention, the first voltage and the second voltage applied between the pixel electrode and the common electrode are integrated as in the above-described driving method of the electrophoretic display device, and adjustment is performed at predetermined intervals based on the integration result. A voltage is applied. Therefore, it is possible to suitably adjust the DC balance ratio while suppressing the occurrence of flicker.

  The electrophoretic display device of the present invention can take the same aspects as the various aspects in the above-described driving method of the electrophoretic display apparatus of the present invention.

  In order to solve the above problems, an electronic apparatus of the present invention includes the above-described electrophoretic display device of the present invention (including various aspects thereof).

  According to the electronic device of the present invention, since the electro-optical device according to the present invention described above is provided, the display quality and reliability are high, for example, wristwatch, electronic paper, electronic notebook, mobile phone, portable audio device, etc. Various electronic devices can be realized.

  The effect | action and other gain of this invention are clarified from the form for implementing invention demonstrated below.

1 is a plan view showing an overall configuration of an electrophoretic display device according to an embodiment. 3 is an equivalent circuit diagram illustrating an electrical configuration of a pixel in the electrophoretic display device according to the embodiment. FIG. It is a fragmentary sectional view of the display part of the electrophoretic display device concerning an embodiment. It is a schematic diagram which shows the structure of a microcapsule. It is a block diagram which shows the specific structure of a controller. 5 is a flowchart illustrating a method for driving the electrophoretic display device according to the embodiment. It is a timing chart which shows a drive voltage when DC balance ratio becomes the same. It is a top view which shows the image displayed by the drive voltage shown in FIG. It is a timing chart which shows a drive voltage when DC balance ratio collapses. It is a top view which shows the image displayed with the drive voltage shown in FIG. It is sectional drawing which shows notionally an electrophoretic element when DC balance ratio collapse | crumbles. It is a timing chart which shows a drive voltage and an adjustment voltage. It is a top view which shows the image displayed by the drive voltage shown in FIG. It is a graph which shows the relationship between the temperature of an electrophoretic element, and the application time of an adjustment voltage. It is a graph which shows the relationship between the temperature of an electrophoretic element, and the voltage value of an adjustment voltage. It is a perspective view which shows the structure of electronic paper. It is a perspective view which shows the structure of an electronic notebook.

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

<Electrophoretic display device and driving method thereof>
An electrophoretic display device and a driving method thereof according to the present embodiment will be described with reference to FIGS. In the following embodiments, a TFT active matrix driving type electrophoretic display device will be described as an example of the electrophoretic display device of the present invention.

  First, the overall configuration of the electrophoretic display device according to the present embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a block diagram showing the overall configuration of the electrophoretic display device according to this embodiment.

  In FIG. 1, the electrophoretic display device 1 according to the present embodiment includes a display unit 3, a controller 10, a scanning line driving circuit 60, a data line driving circuit 70, and a common potential supply circuit 220.

  In the display unit 3, m rows × n columns of pixels 20 are arranged in a matrix (in a two-dimensional plane). The display unit 3 includes m scanning lines 40 (that is, scanning lines Y1, Y2,..., Ym) and n data lines 50 (that is, data lines X1, X2,..., Xn). It is provided so as to cross each other. Specifically, the m scanning lines 40 extend in the row direction (that is, the X direction), and the n data lines 50 extend in the column direction (that is, the Y direction). Pixels 20 are arranged corresponding to the intersections of the m scanning lines 40 and the n data lines 50.

  The controller 10 controls operations of the scanning line driving circuit 60, the data line driving circuit 70, and the common potential supply circuit 220. For example, the controller 10 supplies timing signals such as a clock signal and a start pulse to each circuit.

  Based on the timing signal supplied from the controller 10, the scanning line driving circuit 60 sequentially supplies a scanning signal in a pulse manner to each of the scanning lines Y1, Y2,.

  The data line driving circuit 70 supplies image signals to the data lines X1, X2,..., Xn based on the timing signal supplied from the controller 10. The image signal takes a binary potential of a high potential VH (for example, 15 V) or a low potential VL (for example, 0 V).

  The common potential supply circuit 220 supplies the common potential Vcom to the common potential line 93. Note that the common potential Vcom may be a constant potential, or may vary depending on, for example, the gradation to be written.

  In the present embodiment, as will be described later, the pixel 20 is supplied with the same potential as the common potential Vcom. This may be realized, for example, by setting the common potential Vcom output from the common potential supply circuit 220 to the same potential as the high potential VH or the low potential VL, or from the data line driving circuit 70 to the high potential VH and In addition to the low potential VL, another potential that is the same as the common potential Vcom may be supplied.

  Various signals are input / output to / from the controller 10, the scanning line driving circuit 60, the data line driving circuit 70, and the common potential supply circuit 220. However, those not particularly related to the present embodiment are not described here. .

  FIG. 2 is an equivalent circuit diagram illustrating the electrical configuration of the pixel.

  In FIG. 2, the pixel 20 includes a transistor 24, a pixel electrode 21, a common electrode 22, an electrophoretic element 23, and a storage capacitor 27.

  The transistor 24 is composed of, for example, an N-type transistor. The transistor 24 has a gate electrically connected to the scanning line 40, a source electrically connected to the data line 50, and a drain electrically connected to the pixel electrode 21 and the storage capacitor 27. ing. The transistor 24 is supplied with an image signal supplied from the data line driving circuit 70 (see FIG. 1) via the data line 50 in a pulse manner from the scanning line driving circuit 60 (see FIG. 1) via the scanning line 40. Is output at a timing corresponding to the scanning signal.

  An image signal is supplied to the pixel electrode 21 from the data line driving circuit 70 via the data line 50 and the transistor 24. The pixel electrode 21 is disposed so as to face the common electrode 22 through the electrophoretic element 23.

  The common electrode 22 is electrically connected to a common potential line 93 to which a common potential Vcom is supplied.

  The electrophoretic element 23 is composed of a plurality of microcapsules each containing electrophoretic particles.

  The storage capacitor 27 includes a pair of electrodes arranged to face each other via a dielectric film, one electrode is electrically connected to the transistor 24 and the pixel electrode 21, and the other electrode is electrically connected to the common potential line 93. It is connected to the. According to the storage capacitor 27, the image signal can be maintained for a certain period.

  Next, a specific configuration of the display unit of the electrophoretic display device according to the present embodiment will be described with reference to FIGS. 3 and 4.

  FIG. 3 is a partial cross-sectional view of the display unit of the electrophoretic display device according to this embodiment.

  In FIG. 3, the display unit 3 is configured such that an electrophoretic element 23 is sandwiched between an element substrate 28 and a counter substrate 29. In the present embodiment, description will be made on the assumption that an image is displayed on the counter substrate 29 side.

  The element substrate 28 is a substrate made of, for example, glass or plastic. On the element substrate 28, although not shown here, a stack in which the transistor 24, the storage capacitor 27, the blocking scanning line 40, the data line 50, the common potential line 93 and the like described above with reference to FIG. 2 are formed. A structure is formed. A plurality of pixel electrodes 21 are provided in a matrix on the upper layer side of the stacked structure.

  The counter substrate 29 is a transparent substrate made of, for example, glass or plastic. On the surface of the counter substrate 29 facing the element substrate 28, the common electrode 22 is formed in a solid shape so as to face the plurality of pixel electrodes 9a. The common electrode 22 is formed of a transparent conductive material such as magnesium silver (MgAg), indium / tin oxide (ITO), indium / zinc oxide (IZO), or the like.

  The electrophoretic element 23 is composed of a plurality of microcapsules 80 each including electrophoretic particles, and is fixed between the element substrate 28 and the counter substrate 29 by a binder 30 and an adhesive layer 31 made of, for example, resin. . In the electrophoretic display device 1 according to the present embodiment, in the manufacturing process, an electrophoretic sheet in which the electrophoretic element 23 is previously fixed to the counter substrate 29 side by the binder 30 is separately manufactured, such as the pixel electrode 21. It is constituted by being bonded by an adhesive layer 31 to the element substrate 28 side on which is formed.

  One or a plurality of microcapsules 80 are sandwiched between the pixel electrode 21 and the common electrode 22 and arranged in one pixel 20 (in other words, with respect to one pixel electrode 21).

  FIG. 4 is a schematic diagram showing the configuration of the microcapsule. In addition, in FIG. 4, the cross section of the microcapsule is shown typically.

  In FIG. 4, the microcapsule 80 is formed by enclosing a dispersion medium 81, a plurality of white particles 82, and a plurality of black particles 83 inside a coating 85. The microcapsule 80 is formed in a spherical shape having a particle size of about 50 μm, for example.

  The coating 85 functions as an outer shell of the microcapsule 80 and is formed of a translucent polymer resin such as acrylic resin such as polymethyl methacrylate and polyethyl methacrylate, urea resin, gum arabic, and gelatin. .

  The dispersion medium 81 is a medium for dispersing the white particles 82 and the black particles 83 in the microcapsules 80 (in other words, in the coating 85). Examples of the dispersion medium 81 include water, alcohol solvents such as methanol, ethanol, isopropanol, butanol, octanol, and methyl cellosolve, various esters such as ethyl acetate and butyl acetate, and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. , Aliphatic hydrocarbons such as pentane, hexane and octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, benzene, toluene, xylene, hexylbenzene, hebutylbenzene, octylbenzene, nonylbenzene, decylbenzene, undecyl Aromatic hydrocarbons such as benzenes with long chain alkyl groups such as benzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene, etc., halo such as methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, etc. Emissions of hydrocarbons, carboxylate or other oils may be used singly or as a mixture. In addition, a surfactant may be added to the dispersion medium 81.

  The white particles 82 are particles (polymer or colloid) made of a white pigment such as titanium dioxide, zinc white (zinc oxide), and antimony trioxide, and are negatively charged, for example.

  The black particles 83 are particles (polymer or colloid) made of a black pigment such as aniline black or carbon black, and are positively charged, for example.

  For this reason, the white particles 82 and the black particles 83 can move in the dispersion medium 81 by the electric field generated by the potential difference between the pixel electrode 21 and the common electrode 22.

  These pigments include electrolytes, surfactants, metal soaps, resins, rubbers, oils, varnishes, charge control agents composed of particles such as compounds, titanium-based coupling agents, aluminum-based coupling agents, silanes as necessary. A dispersant such as a system coupling agent, a lubricant, a stabilizer, and the like can be added.

  In addition, red, green, blue, etc. can be displayed by replacing the pigment used for the white particle 82 and the black particle 83 with pigments, such as red, green, and blue, for example.

  Next, a more specific configuration of the electrophoretic display device according to the present embodiment will be described with reference to FIG.

  FIG. 5 is a block diagram showing a specific configuration of the controller.

  5, the controller 10 (see FIG. 1) of the electro-optical device according to the present embodiment includes a temperature detection unit 310, a drive voltage supply unit 320, an integration unit 330, an adjustment voltage determination unit 340, and an adjustment voltage supply. Part 350.

  The temperature detection unit 310 is electrically connected to, for example, a temperature sensor provided around the display unit 3 and configured to detect the temperature of the electrophoretic element 23.

  The drive voltage supply unit 320 applies a drive voltage corresponding to an image to be displayed to the display unit 3 (more specifically, between the pixel electrode 21 and the common electrode 22).

  The integration unit 330 is electrically connected to the drive voltage supply unit 320, and is configured to be able to integrate the drive voltage applied to the display unit 3. Specifically, it is integrated to which pixel at what voltage value and for how long the drive voltage has been applied.

  The adjustment voltage determination unit 340 calculates the voltage value or application time of the adjustment voltage based on the drive voltage accumulated in the accumulation unit 330. The adjustment voltage will be described in detail later.

  The adjustment voltage supply unit 350 applies the adjustment voltage to the display unit 3 under the conditions determined by the adjustment voltage determination unit 340.

  The controller 10 may include circuits other than the above-described temperature detection unit 310, drive voltage supply unit 320, integration unit 330, adjustment voltage determination unit 340, and adjustment voltage supply unit 350.

  Next, a driving method of the electrophoretic display device according to this embodiment will be described with reference to FIGS.

  FIG. 6 is a flowchart showing a driving method of the electrophoretic display device according to this embodiment.

  In FIG. 6, in the driving method of the electrophoretic display device according to the present embodiment, first, the temperature detection unit 310 detects the temperature of the electrophoretic element 23 (step S01). The temperature of the electrophoretic element 23 may be detected directly from the electrophoretic element 23, or may be indirectly detected from the pixel electrode 21, the common electrode 22, or other members, for example.

  Subsequently, the drive voltage supply unit 320 applies a drive voltage for displaying an image (step S02). That is, a voltage corresponding to the image signal is applied between the pixel electrode 21 and the common electrode 22, and white or black is displayed in each pixel 20. Therefore, an image corresponding to the image signal is displayed on the display unit 3.

  FIG. 7 is a timing chart showing the drive voltage when the DC balance ratio is the same, and FIG. 8 is a plan view showing an image displayed by the drive voltage shown in FIG.

  7 and 8, for example, the drive voltage supply unit 320 applies a drive voltage to the counter electrode, the pixel electrode A, and the pixel electrode B with a pulse as shown in FIG. In this case, in each period from a-1 to a-4, an image as shown in FIG.

  Returning to FIG. 6, when the drive voltage is applied, the integration unit 330 integrates the applied drive voltage (step S03). That is, what voltage is applied to which pixel is stored, and integration is performed according to the voltage value and application time. Thereby, it is possible to know the DC balance ratio applied to each pixel.

  Subsequently, the adjustment voltage determination unit 340 determines whether or not a predetermined period has elapsed since the drive voltage began to be applied (step S04). When the predetermined period has not elapsed (step S04: NO), the process returns to step S02, and the drive voltage is applied again. On the other hand, when the predetermined period has elapsed (step S04: YES), the adjustment voltage is calculated based on the temperature of the electrophoretic element detected by the temperature detection unit 310 and the integration result at the integration unit 330 at that time. Calculate (step S05).

  The adjustment voltage determined by the adjustment voltage determination unit 340 is applied to the display unit 3 by the adjustment voltage supply unit 350.

  FIG. 9 is a timing chart showing the drive voltage when the DC balance ratio is lost, and FIG. 10 is a plan view showing an image displayed by the drive voltage shown in FIG.

  9 and 10, for example, it is assumed that the drive voltage is applied by the drive voltage supply unit 320 to the counter electrode, the pixel electrode A, and the pixel electrode B with a pulse as illustrated in FIG. 9. In this case, images shown in FIG. 10 are displayed on the display unit 3 in each period of b-1 and b-2. 9 and FIG. 10, the DC balance ratio is lost in the pixel electrode A and the pixel electrode B. That is, as in the case shown in FIGS. 7 and 8, the DC balance ratio does not become 50:50.

  FIG. 11 is a cross-sectional view conceptually showing an electrophoretic element when the DC balance ratio is broken.

  In FIG. 11, the inventor of the present application speculates that when the DC balance ratio collapses, the following situation occurs. That is, when the DC balance ratio is lost, first, ions in the solvent 81 of the electrophoretic element 23 are unevenly distributed near an electrode having a polarity opposite to that of the ions. Then, a leak current flows between the pixel electrodes 21 adjacent to each other, and ions cause an electrochemical reaction. As a result, the electrodes, the electrophoretic elements, and the like are deteriorated, which affects the migration of the electrophoretic particles.

  In the driving method of the electro-optical device according to the present embodiment, an adjustment voltage is applied every predetermined period in order to prevent a problem that occurs when the DC balance ratio as described above is lost.

  FIG. 12 is a timing chart showing the drive voltage and the adjustment voltage, and FIG. 13 is a plan view showing an image displayed by the drive voltage shown in FIG.

  12 and 13, the adjustment voltage is applied as a voltage as shown in FIG. 12, for example. Specifically, a high-level adjustment voltage is applied in the period c-3 to the pixel electrode A whose voltage was not set to the high level in the periods c-1 and c-2. As illustrated in FIG. 13, the display unit 3 displays a reverse image of the image displayed in the period c-2 in the period c-3 in which the adjustment voltage is applied. In this way, it is possible to adjust the collapse of the DC balance ratio between pixels. Therefore, various inconveniences due to the collapse of the DC balance ratio can be prevented.

  Further, in the present embodiment, the above-described adjustment voltage is applied collectively at predetermined intervals. If an adjustment voltage is applied every time an image is rewritten, images with different gradations are alternately displayed in a short time, and flickering occurs. On the other hand, if the adjustment voltage is applied together every predetermined period, the image switching frequency can be greatly reduced. Therefore, flicker can be prevented. In other words, the predetermined period according to the present embodiment is set as a period that is long enough to prevent flickering. However, from the viewpoint of not destroying the DC balance ratio, it is preferable that the predetermined period is shorter. According to the research of the present inventor, for example, by setting the predetermined period to 60 seconds or more, it has been found that the DC balance ratio can be maintained to such an extent that the flicker is suitably prevented and no malfunction occurs.

  FIG. 14 is a graph showing the relationship between the temperature of the electrophoretic element and the application time of the adjustment voltage.

  In FIG. 14, the adjustment voltage adjusts the collapse of the DC balance ratio, for example, by adjusting the application time thereof. Specifically, as can be seen from the figure, the application time is preferably shortened as the temperature is lower.

  FIG. 15 is a graph showing the relationship between the temperature of the electrophoretic element and the voltage value of the adjustment voltage.

  In FIG. 15, the voltage value of the adjustment voltage may be adjusted. Specifically, the voltage value is preferably increased as the temperature is lower. It is also possible to adjust both the application time and the voltage value.

  As described above, according to the driving method of the electro-optical device according to the present embodiment, it is possible to suitably adjust the DC balance ratio by applying the adjustment voltage every predetermined period.

<Electronic equipment>
Next, electronic devices to which the above-described electrophoretic display device is applied will be described with reference to FIGS. Below, the case where the electrophoretic display device described above is applied to electronic paper and an electronic notebook is taken as an example.

  FIG. 16 is a perspective view illustrating a configuration of the electronic paper 1400.

  As illustrated in FIG. 16, the electronic paper 1400 includes the electrophoretic display device according to the above-described embodiment as a display unit 1401. The electronic paper 1400 has flexibility, and includes a main body 1402 formed of a rewritable sheet having the same texture and flexibility as conventional paper.

  FIG. 17 is a perspective view illustrating a configuration of the electronic notebook 1500.

  As shown in FIG. 17, an electronic notebook 1500 is one in which a plurality of electronic papers 1400 shown in FIG. 16 are bundled and sandwiched between covers 1501. The cover 1501 includes display data input means (not shown) for inputting display data sent from an external device, for example. Thereby, according to the display data, the display content can be changed or updated while the electronic paper is bundled.

  Since the electronic paper 1400 and the electronic notebook 1500 described above include the electrophoretic display device according to the above-described embodiment, the electronic paper 1400 and the electronic notebook 1500 can display images with high reliability and high quality.

  In addition to these, the electrophoretic display device according to the present embodiment described above can be applied to the display unit of an electronic device such as a wristwatch, a mobile phone, or a portable audio device.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and an electrophoretic display with such a change. An apparatus driving method, an electrophoretic display device, and an electronic apparatus are also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 3 ... Display part, 10 ... Controller, 20 ... Pixel, 21 pixel electrode, 22 ... Common electrode, 23 ... Electrophoretic element, 24 ... Transistor, 27 ... Retention capacity, 28 ... Element substrate, 29 ... Counter substrate, 40 ... Scanning 50, data line, 60 ... scanning line drive circuit, 70 ... data line drive circuit, 80 ... microcapsule, 82 ... white particle, 83 ... black particle, 93 ... common potential line, 220 ... common potential supply circuit, 310 ... Temperature detection unit 320 ... Drive voltage supply unit 330 ... Integration unit 340 ... Adjustment voltage determination unit 350 ... Adjustment voltage supply unit

Claims (6)

A method of driving an electrophoretic display device in which an electrophoretic element including electrophoretic particles is provided between a pixel electrode and a common electrode facing each other,
A display step of applying a first voltage corresponding to a first color and a second voltage corresponding to a second color between the pixel electrode and the common electrode; and the first voltage applied in the display step. Integrating for the applied time and integrating for the time for applying the second voltage;
It is determined whether or not a predetermined period including a plurality of the display processes has elapsed since the start of the display process, and when the predetermined period has elapsed, an adjustment process for applying an adjustment voltage;
With
In the adjustment step, when the integration value of the second voltage is larger than the integration value of the first voltage in the integration step, an adjustment voltage having the same polarity as the first voltage is applied. Driving method.   2. The adjustment step according to claim 1, wherein in the adjustment step, the adjustment voltage is a predetermined voltage, and is applied for a time corresponding to a ratio of the first voltage and the second voltage integrated in the integration step. Driving method of electrophoretic display device.   2. The adjustment step according to claim 1, wherein the adjustment voltage is a voltage corresponding to a ratio of the first voltage and the second voltage integrated in the integration step, and is applied for a predetermined time. Driving method of electrophoretic display device. A temperature detection step of detecting the temperature of the electrophoretic element;
4. The driving method of the electrophoretic display device according to claim 1, wherein, in the adjustment step, the adjustment voltage is applied based on a temperature of the electrophoretic element. 5. A pixel electrode and a common electrode facing each other;
An electrophoretic element including electrophoretic particles provided between the pixel electrode and the common electrode;
Display means for applying a first voltage corresponding to a first color and a second voltage corresponding to a second color between the pixel electrode and the common electrode;
Integrating means for integrating the time when the first voltage applied by the display means is applied and integrating the time for applying the second voltage;
When a predetermined period including a plurality of times of application of the first voltage and the second voltage has elapsed from the application of the first voltage and the second voltage, and when the predetermined period has elapsed An electrophoretic display device comprising: adjustment means for applying an adjustment voltage having the same polarity as the first voltage when the integrated value of the second voltage is larger than the integrated value of the first voltage.   An electronic apparatus comprising the electrophoretic display device according to claim 5.

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