JP2012063618A - Method for driving electrophoretic display device, electrophoretic display device, control circuit for electrophoretic display device, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for driving an electrophoretic display device for obtaining fast optical responsiveness in a simple pixel structure.SOLUTION: An electrophoretic display device includes a display unit having an electrophoretic element held between a pair of substrates and an array of a plurality of pixels, the pixel provided with a control transistor, a memory element connected to a drain of the control transistor, a drive transistor the gate of which is connected to the drain of the control transistor, a pixel electrode connected to the drain of the drive transistor, and a counter electrode opposing to the pixel electrode through the electrophoretic element. The method for driving the device comprises inputting a first potential and a second potential different from each other, each at least once, to the source of the drive transistor in an image display period when an image is displayed on the display unit by driving the pixels.

Description

  The present invention relates to an electrophoretic display device driving method, an electrophoretic display device, an electrophoretic display device control circuit, and an electronic apparatus.

  Various active matrix electrophoretic display devices are known. For example, an electrophoretic display device disclosed in Patent Document 1 includes a latch circuit and a switch circuit in a pixel, and operates the switch circuit based on an image signal held in the latch circuit, whereby the first control line Alternatively, the display is performed by selectively connecting the second control line to the pixel electrode.

JP 2008-268853 A

In the electrophoretic display device, a display state is changed by applying a voltage to an electrophoretic element including electrophoretic particles and a dispersion medium. At this time, when a voltage is continuously applied to the electrophoretic element, a phenomenon is observed in which the optical response of the electrophoretic element becomes slower than when the voltage is intermittently applied. Therefore, in the electrophoretic display device described in Patent Literature 1, a pulse-shaped rectangular wave is input to the common electrode, and an image is displayed by alternately applying a voltage that causes the electrophoretic element to display white and a voltage that causes the electrophoretic element to display black. It was displayed.
However, the electrophoretic display device described in Patent Document 1 requires a complicated pixel structure using seven or nine transistors per pixel.

  The present invention has been made in view of the above-described problems of the prior art, and a driving method of an electrophoretic display device capable of obtaining high-speed optical response in a simple pixel structure, and an electrophoretic display device, Another object is to provide an electrophoretic display device control circuit.

  The driving method of the electrophoretic display device of the present invention includes a display unit in which an electrophoretic element is sandwiched between a pair of substrates and a plurality of pixels are arranged. The pixel includes a control transistor and a drain of the control transistor. A connected memory element; a drive transistor having a gate connected to the drain of the control transistor; a pixel electrode connected to the drain of the drive transistor; and a counter electrode facing the pixel electrode via the electrophoretic element In the image display period in which the pixel is driven to display an image on the display unit, the first potential different from each other with respect to the source of the driving transistor is provided. The second potential is input at least once.

  According to this driving method, since different voltages are applied to the electrophoretic element during the image display period in which the electrophoretic element is driven, it is possible to suppress the dissimilar electrophoretic particles contained in the electrophoretic element from interfering with each other. can do. Accordingly, it is possible to smoothly migrate the electrophoretic particles during the image display period, and a high-speed optical response can be obtained while using a simple pixel of two transistors.

The first potential and the second potential may be a driving method in which polarities with respect to the potential of the counter electrode are opposite to each other.
According to this driving method, a force (electric field) that temporarily drives in the opposite direction can be applied to the electrophoretic particles, so that different types of electrophoretic particles in a collision state can be separated, and electrophoresis can be performed. Particle migration can be made smoother.

A driving method in which a difference between any one of the first potential and the second potential and the potential of the counter electrode is equal to or lower than a threshold voltage of the electrophoretic element. That is, a driving method in which one of the first potential and the second potential is substantially the same as the potential of the counter electrode.
According to this driving method, since the movement of the electrophoretic particles can be temporarily stopped temporarily during the image display period, the force with which the different electrophoretic particles in the collision state are pressed against each other can be reduced. Thereby, electrophoresis of electrophoretic particles can be smoothed and a high-speed optical response can be obtained.

A driving method in which a potential waveform that periodically repeats the first potential and the second potential may be input to the source of the driving transistor.
According to this driving method, a high-speed optical response can be realized while using a simple waveform. The potential waveform is not limited to a rectangular wave, and may be a sine wave, a triangular wave, a sawtooth wave, or the like.

A driving method in which a first period in which the first potential is input to the source of the driving transistor and a second period in which the second potential is input have different lengths may be employed.
According to this driving method, driving optimized in accordance with the characteristics of the electrophoretic element can be performed. Further, if the period during which the electrophoretic element is not substantially driven is shortened, display switching can be executed in a shorter time.

A driving method in which potential waveforms having different phases are input to the driving transistors of the two pixels adjacent in the row direction or the column direction in the display portion may be employed.
According to this driving method, since a horizontal electric field can be generated between the two pixels, the different types of electrophoretic particles in a collision state can be separated by the action of the electric field. Thereby, a faster optical response can be realized.

A plurality of scanning lines and a plurality of data lines extending in directions intersecting each other are formed on the display portion, and the plurality of pixels are provided at positions corresponding to intersections of the plurality of scanning lines and the plurality of data lines. In the case where the period for sequentially selecting the plurality of scanning lines once is set to one frame, an image signal for shifting the driving transistor to the ON state in the first frame is input to the pixel, A driving method may be used in which an image signal for shifting the driving transistor to an off state is input to the pixel in a second frame after the first frame.
According to this driving method, it is possible to display halftone while obtaining a high-speed optical response.

A driving method for controlling display gradation of the pixel according to a length of a period from the first frame to the second frame may be employed.
According to this driving method, finer gradation control can be performed.

An image signal input period in which the image signal is input to the pixel in a state where a potential substantially the same as the potential of the counter electrode is input to the source of the driving transistor, and the image display period following the image signal input period Driving in which an image is displayed on the display unit by repeating a unit display period a plurality of times, and an on / off state of the driving transistor in the corresponding image display period is selected by an image signal input to the pixel in the image signal input period It is good also as a method.
According to this driving method, the display gradation of the pixel can be easily controlled.

During the image display period, the operation of inputting the image signal to the pixel is performed over a plurality of frames, and the drive transistor is turned on in the image display period by the image signal input to the pixel for each frame. It is good also as a method of setting the length of the period to be performed.
According to this driving method, since the electrophoretic element is driven even when an image signal is input, the time required for display switching can be shortened.

  An electrophoretic display device of the present invention includes a display unit in which an electrophoretic element is sandwiched between a pair of substrates and a plurality of pixels are arranged, and the pixel is connected to a control transistor and a drain of the control transistor. A memory element, a driving transistor having a gate connected to the drain of the control transistor, a pixel electrode connected to the drain of the driving transistor, and a counter electrode facing the pixel electrode through the electrophoretic element are provided. The electrophoretic display device includes a control unit that drives and controls the display unit, and the control unit drives the pixel to display the image on the display unit and displays the image on the source of the drive transistor. On the other hand, the first potential and the second potential different from each other are input at least once.

  According to this configuration, since different voltages are applied to the electrophoretic element during the image display period in which the electrophoretic element is driven, it is possible to suppress dissimilar electrophoretic particles contained in the electrophoretic element from interfering with each other. be able to. Accordingly, it is possible to smoothly migrate the electrophoretic particles during the image display period, and a high-speed optical response can be obtained while using a simple pixel of two transistors.

  The control circuit for an electrophoretic display device of the present invention includes a display unit in which an electrophoretic element is sandwiched between a pair of substrates, and a plurality of pixels are arranged. The pixel includes a control transistor, A memory element connected to the drain of the control transistor; a drive transistor having a gate connected to the drain of the control transistor; a pixel electrode connected to the drain of the drive transistor; and the pixel electrode via the electrophoretic element A control circuit that can be applied to an electrophoretic display device provided with a counter electrode opposite to the source electrode of the drive transistor during an image display period in which the pixel is driven to display an image on the display unit. The first potential and the second potential different from each other are input at least once.

  According to this control circuit, since different voltages are applied to the electrophoretic element during the image display period in which the electrophoretic element is driven, it is possible to suppress the dissimilar electrophoretic particles contained in the electrophoretic element from interfering with each other. can do. Accordingly, it is possible to smoothly migrate the electrophoretic particles during the image display period, and a high-speed optical response can be obtained while using a simple pixel of two transistors.

An electronic apparatus according to the present invention includes the electrophoretic display device described above.
According to this configuration, it is possible to provide an electronic apparatus including a display unit that can perform high-speed display switching.

1 is a schematic configuration diagram of an electrophoretic display device according to a first embodiment. The circuit block diagram of a pixel. The fragmentary sectional view of an electrophoretic display device, and the sectional view of a microcapsule. Operation | movement explanatory drawing of an electrophoretic element. The timing chart which shows the drive method of embodiment. The figure which showed operation | movement of the pixel in an image display step. The figure which shows the modification of an electric potential waveform. The timing chart which shows the 1st halftone display drive method. The timing chart which shows the 2nd halftone display drive method. The figure which shows the principal part of the electrophoretic display device which concerns on 2nd Embodiment. The figure which shows the modification of the electrophoretic display device which concerns on 2nd Embodiment. The figure which shows the principal part of the electrophoretic display device which concerns on 3rd Embodiment. The figure which shows the electric potential waveform supplied to a power wire. The front view of a wristwatch. The perspective view which shows the structure of electronic paper. The perspective view which shows the structure of an electronic notebook.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The scope of the present invention is not limited to the following embodiment, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, the actual structure may be different from the scale, number, or the like in each structure.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an electrophoretic display device 100 according to the first embodiment.
The electrophoretic display device 100 includes a display unit 5 in which a plurality of pixels 40 are arranged in a matrix. Around the display unit 5, a scanning line drive circuit 61, a data line drive circuit 62, a controller (control unit, control circuit) 63, and a common power supply modulation circuit 64 are arranged. The scanning line driving circuit 61, the data line driving circuit 62, and the common power supply modulation circuit 64 are each connected to the controller 63. The controller 63 comprehensively controls the electrophoretic display device 100 based on image data and a synchronization signal supplied from the host device.

  A plurality of scanning lines 66 extending from the scanning line driving circuit 61 and a plurality of data lines 68 extending from the data line driving circuit 62 are formed in the display unit 5, and the pixels 40 are provided corresponding to the intersection positions thereof. It has been. A plurality of power supply lines 50 extend from the common power supply modulation circuit 64 to the display unit 5. The power supply line 50 is provided corresponding to the scanning line 66 of each row, and is connected to the pixel 40 of the corresponding row. The common power supply modulation circuit 64 is configured such that potential can be individually input to each power supply line 50.

The scanning line driving circuit 61 is connected to each pixel 40 via m scanning lines 66 (Y1, Y2,..., Ym). Under the control of the controller 63, the first to mth rows are connected. The scanning lines 66 are sequentially selected, and a selection signal defining the ON timing of the control transistor TRc (see FIG. 2) provided in the pixel 40 is supplied via the selected scanning line 66.
The data line driving circuit 62 is connected to each pixel 40 via n data lines 68 (X1, X2,..., Xn), and corresponds to each pixel 40 under the control of the controller 63. An image signal defining pixel data is supplied to the pixel 40. The common power supply modulation circuit 64 generates various signals to be supplied to each of the power supply lines 50 connected to the circuit under the control of the controller 63, while electrically connecting and disconnecting these wirings (high impedance). (Hi-Z)).

FIG. 2 is a circuit configuration diagram of the pixel 40.
The pixel 40 is provided with a control transistor TRc, a drive transistor TRd, a storage capacitor C1, a pixel electrode 35, an electrophoretic element 32, and a common electrode 37. Further, a scanning line 66, a data line 68, and a power supply line 50 are connected to the pixel 40. The control transistor TRc and the drive transistor TRd are both N-MOS (Negative Metal Oxide Semiconductor) transistors.
Note that each transistor constituting the pixel 40 may be replaced with another type of switching element having the same function as the transistor. For example, a P-MOS transistor may be used instead of the N-MOS transistor.

  In the pixel 40, the scanning line 66 is connected to the gate of the control transistor TRc, and the data line 68 is connected to the source. The drain of the control transistor TRc is connected to one electrode of the storage capacitor C1 and the gate of the drive transistor TRd. The source of the driving transistor TRd is connected to the power supply line 50, and the drain is connected to the pixel electrode 35. The electrophoretic element 32 is sandwiched between the pixel electrode 35 and the common electrode 37. The other electrode of the storage capacitor C1 is connected to a capacitor line (not shown) or a power supply line 50.

  The control transistor TRc is a switching element that controls the input of the image signal to the pixel 40, and the image signal voltage supplied via the control transistor TRc is held in the holding capacitor C1. Then, the electrophoretic element 32 is driven with a current corresponding to the voltage of the storage capacitor C1, that is, the gate potential of the driving transistor TRd.

  Next, FIG. 3A is a partial cross-sectional view of the electrophoretic display device 100 in the display unit 5. The electrophoretic display device 100 includes a configuration in which an electrophoretic element 32 formed by arranging a plurality of microcapsules 20 is sandwiched between an element substrate (first substrate) 30 and a counter substrate (second substrate) 31. Yes.

In the display unit 5, the circuit layer 34 on which the scanning line 66, the data line 68, the control transistor TRc, the driving transistor TRd, and the like illustrated in FIGS. 1 and 2 are formed is provided on the electrophoretic element 32 side of the element substrate 30. A plurality of pixel electrodes 35 are arranged on the circuit layer 34.
The element substrate 30 is a substrate made of glass, plastic, or the like and is not required to be transparent because it is disposed on the side opposite to the image display surface. The pixel electrode 35 has a voltage applied to an electrophoretic element 32 formed by laminating nickel plating and gold plating on a Cu (copper) foil in this order, Al (aluminum), ITO (indium tin oxide), or the like. Is an electrode to which is applied.

On the other hand, a planar common electrode 37 facing the plurality of pixel electrodes 35 is formed on the electrophoretic element 32 side of the counter substrate 31, and the electrophoretic element 32 is provided on the common electrode 37.
The counter substrate 31 is a substrate made of glass, plastic, or the like, and is a transparent substrate because it is disposed on the image display side. The common electrode 37 is an electrode for applying a voltage to the electrophoretic element 32 together with the pixel electrode 35, and is formed of MgAg (magnesium silver), ITO (indium tin oxide), IZO (indium zinc oxide) or the like. It is a transparent electrode.
The electrophoretic element 32 and the pixel electrode 35 are bonded via the adhesive layer 33, so that the element substrate 30 and the counter substrate 31 are bonded.

  In general, the electrophoretic element 32 is formed in advance on the counter substrate 31 side, and is handled as an electrophoretic sheet including the adhesive layer 33. In the manufacturing process, the electrophoretic sheet is handled in a state where a protective release sheet is attached to the surface of the adhesive layer 33. And the display part 5 is formed by sticking the said electrophoretic sheet which peeled the release sheet with respect to the element board | substrate 30 (The pixel electrode 35, various circuits, etc.) which were manufactured separately. For this reason, the adhesive layer 33 exists only on the pixel electrode 35 side.

  FIG. 3B is a schematic cross-sectional view of the microcapsule 20. The microcapsule 20 has a particle size of, for example, about 50 μm and encloses therein a dispersion medium 21, a plurality of white particles (electrophoretic particles) 27, and a plurality of black particles (electrophoretic particles) 26. It is a spherical body. As shown in FIG. 3A, the microcapsule 20 is sandwiched between the common electrode 37 and the pixel electrode 35, and one or more microcapsules 20 are disposed in one pixel 40.

The outer shell portion (wall film) of the microcapsule 20 is formed using a translucent polymer resin such as an acrylic resin such as polymethyl methacrylate or polyethyl methacrylate, a urea resin, or gum arabic.
The dispersion medium 21 is a liquid that disperses the white particles 27 and the black particles 26 in the microcapsules 20. Examples of the dispersion medium 21 include water, alcohol solvents (methanol, ethanol, isopropanol, butanol, octanol, methyl cellosolve, etc.), esters (ethyl acetate, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). ), Aliphatic hydrocarbons (pentane, hexane, octane, etc.), alicyclic hydrocarbons (cyclohexane, methylcyclohexane, etc.), aromatic hydrocarbons (benzene, toluene, benzenes having a long-chain alkyl group ( Xylene, hexylbenzene, hebutylbenzene, octylbenzene, nonylbenzene, decylbenzene, undecylbenzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene)), halogenated hydrocarbons (methylene chloride, chloroform, tetrachloride) Element, and 1,2-dichloroethane), can be exemplified a carboxylate, it may be other oils. These substances can be used alone or as a mixture, and a surfactant or the like may be further blended.

The white particles 27 are particles (polymer or colloid) made of a white pigment such as titanium dioxide, zinc white, and antimony trioxide, and are used, for example, by being positively charged. The black particles 26 are particles (polymer or colloid) made of a black pigment such as aniline black or carbon black, and are used, for example, by being negatively charged.
These pigments include electrolytes, surfactants, metal soaps, resins, rubbers, oils, varnishes, compound charge control agents, 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.
Further, instead of the black particles 26 and the white particles 27, for example, pigments such as red, green, and blue may be used. According to such a configuration, red, green, blue, or the like can be displayed on the display unit 5. Also, the number of electrophoretic particles is not limited to two, but may be one or three or more. Further, the electrophoretic element 32 is not limited to the configuration in which the microcapsules 20 are arranged, and the electrophoretic dispersion liquid (in which electrophoretic particles are dispersed in a dispersion medium) is partitioned by a partition formed on the substrate. Also good.

FIG. 4 is an operation explanatory diagram of the electrophoretic element. 4A shows a case where the pixel 40 displays white, and FIG. 4B shows a case where the pixel 40 displays black.
In the case of white display shown in FIG. 4A, the common electrode 37 is held at a relatively low potential, and the pixel electrode 35 is held at a relatively high potential. As a result, the positively charged white particles 27 are attracted to the common electrode 37, while the negatively charged black particles 26 are attracted to the pixel electrode 35. As a result, when this pixel is viewed from the common electrode 37 side which is the display surface side, white (W) is recognized.
In the case of black display shown in FIG. 4B, the common electrode 37 is held at a relatively high potential and the pixel electrode 35 is held at a relatively low potential. As a result, the negatively charged black particles 26 are attracted to the common electrode 37, while the positively charged white particles 27 are attracted to the pixel electrode 35. As a result, when this pixel is viewed from the common electrode 37 side, black (B) is recognized.
FIG. 4 is an explanatory diagram of the operation when the black particles are negative and the white particles are positively charged. However, if necessary, the black particles may be positively charged and the white particles negatively charged. Good. In this case, when a potential is supplied in the same manner as described above, a display in which white display and black display are reversed can be obtained.

[Driving method]
Next, a driving method of the electrophoretic display device of this embodiment will be described.
FIG. 5 is a timing chart showing the driving method of this embodiment. FIG. 6 is an explanatory diagram of the operation of the pixel.
The driving method of the electrophoretic display device of the present embodiment includes an image signal input step (image signal input period) S101, an image display step (image display period) S102, and a drive stop step S103 shown in FIG.

  First, in the image signal input step S101, image signal input to the pixels 40 of the display unit 5 is executed. That is, the scanning line drive circuit 61 sequentially selects the scanning lines 66 (Y1, Y2,..., Ym), and a selection signal for turning on the control transistor TRc is input to the selected scanning lines 66. On the other hand, a non-selection signal for turning off the control transistor TRc is input to the unselected scanning line 66. In each pixel 40, during the period when the selection signal is input, the image signal supplied from the data line driving circuit 62 is input to the storage capacitor C1 via the control transistor TRc in the ON state, and the storage capacitor C1 is set to a predetermined value. (The voltage of the image signal). Here, the image signal includes a voltage for turning on the driving transistor TRd (on pixel voltage) and a voltage for turning off the driving transistor TRd (off pixel voltage).

  Then, the drive transistor TRd is on / off controlled based on the image signal voltage held in the holding capacitor C1. Specifically, when the on-pixel voltage is held in the holding capacitor C1, the driving transistor TRd is turned on, and the power supply line 50 and the pixel electrode 35 are electrically connected. On the other hand, when the off-pixel voltage is held in the holding capacitor C1, the driving transistor TRd is turned off.

Even when the selection period of the scanning line 66 ends and the control transistor TRc is turned off, the image signal voltage is held in the holding capacitor C1, and therefore the operation of the drive transistor TRd by the holding voltage of the holding capacitor C1. State is maintained.
In the present embodiment, in the image signal input step S101, the potential Vdd of the power supply line 50 is held at the same potential as the potential Vcom of the common electrode 37. Therefore, during the period of the image signal input step S101, the electrophoretic element 32 is driven because there is no potential difference between the pixel electrode 35 and the common electrode 37 of the pixel 40 in which the drive transistor TRd is turned on. There is nothing.

Next, when proceeding to the image display step S102, as shown in FIG. 5, the first potential higher than the potential Vcom of the common electrode 37 and the second potential that is the same potential as the potential Vcom of the common electrode 37 with respect to the power supply line 50. A rectangular wave that periodically repeats the potential is supplied. Then, the rectangular wave is input to the pixel electrode 35 in the pixel 40 in which the driving transistor TRd is turned on.
Note that the second potential in the image display step S102 does not have to be exactly the same as the potential Vcom, and the potential difference with the potential Vcom is the threshold voltage Vt of the electrophoretic element 32 (the lowest voltage that can move the electrophoretic particles; Vt> 0) or less (Vcom ± Vt) can also be changed.

  Here, FIGS. 6A to 6F are diagrams illustrating the operation of the pixel 40 in the image display step S102. FIG. 6 shows an operation in a case where a part of the pixels 40 is shifted to black display from a state where the display unit 5 is displayed in white on the entire surface and a black and white image is formed on the display unit 5. In FIG. 6, the pixel 40 having the pixel electrode 35A is a pixel that is shifted to black display in the image display step S102, and the pixel 40 having the pixel electrode 35B is a pixel that remains white and does not change.

  In the image display step S102, the first potential and the second potential are alternately input to the pixel electrode 35A. When the pixel electrode 35A is at the first potential as shown in FIG. 6B from the entire white display state shown in FIG. 6A, the black particles 26 are shared by the potential difference between the pixel electrode 35A and the common electrode 37. The white particles 27 begin to move toward the pixel electrode 35A toward the 37 side. However, as shown in FIG. 6C, the potential of the pixel electrode 35A again becomes the second potential (the same potential as the potential Vcom of the common electrode 37) in a short period, and the movement of the black particles 26 and the white particles 27 is stopped. To do. Thereafter, as shown in FIG. 6D, when the potential of the pixel electrode 35A becomes the first potential again, the movement of the black particles 26 and the white particles 27 is resumed. Thus, in the present embodiment, the black particles 26 and the white particles 27 gradually shift to black display while repeating the movement and the stop.

If an image based on the image signal is displayed on the display unit 5, a drive stop step S103 is executed. In the drive stop step S103, the supply of the rectangular wave to the power supply line 50 is stopped, and the second potential (the same potential as the potential Vcom of the common electrode 37) is supplied to the power supply line 50. Further, the scanning line 66 is sequentially selected by the scanning line driving circuit 61, and an off-pixel voltage for turning off the driving transistor TRd is supplied from the data line driving circuit 62 to the data line 68 in accordance with the selection timing of the pixel 40. Is done. As a result, the off-pixel voltage is held in the holding capacitor C1 of all the pixels 40, and the driving transistor TRd is turned off. Thereby, the pixel 40 is shifted to a state where the display does not change.
Alternatively, the off-pixel voltage may be supplied to the storage capacitors C1 of all the pixels 40 by simultaneously selecting the scanning lines 66 of all the rows.

  As described above, in the method for driving the electrophoretic display device according to the present embodiment, by inputting a rectangular wave to the power supply line 50 in the image display step S102, the electrophoretic element 32 is intermittently formed as shown in FIG. To drive. Thereby, it is possible to suppress a decrease in response speed that occurs when a voltage is continuously applied to the electrophoretic element 32 and to obtain a high-speed optical response.

  The slowing of the response speed is considered to occur because the black particles 26 and the white particles 27 inhibit the movement of each other. More specifically, when moving from FIG. 6B to FIG. 6D, the black particles 26 and the white particles 27 pass each other, but when a constant voltage is continuously applied to the electrophoretic element 32. The black particles 26 are moved from the vicinity of the pixel electrode 35A to the vicinity of the common electrode 37, and the white particles 27 are moved from the vicinity of the common electrode 37 to the vicinity of the pixel electrode 35A. Therefore, when the black particles 26 and the white particles 27 collide during movement, they are pressed against each other and cannot move.

In contrast, in the driving method of the present embodiment, the black particles 26 and the white particles 27 are moved intermittently, so even if they collide and push each other, the pixel electrode 35A and the common electrode During the period when 37 is at the same potential, the force of pressing the particles is lost, and the particles can be separated. Thereby, when the black particles 26 and the white particles 27 move next time, they can be passed smoothly, and it is considered that the response speed is prevented from being slowed down.
Note that the driving method of the present embodiment is effective even when the electrophoretic element includes only one type of charged particle (electrophoretic particle). That is, with one type of charged particle, if a DC voltage is continuously applied, the charged particles may agglomerate with each other and the apparent particle movement speed may be slowed down. The optical response can be made faster.

In the present embodiment, the period of the rectangular wave input to the power supply line 50 is not particularly limited, and can be set according to the response characteristics of the electrophoretic element 32 and the like. Specifically, for example, the cycle can be set to 5 ms to 200 ms.
Furthermore, although the duty of the rectangular wave is 50% in FIG. 5, the period of the first potential may be lengthened as shown in FIG. For example, when the period is 20 ms, the first potential may be 15 ms and the second potential may be 5 ms. In the case of the present embodiment, the period in which the potential Vdd is the second potential is a period in which the electrophoretic element 32 is not driven. Therefore, by shortening the period of the second potential within a range in which the above-described effect can be obtained, The optical response can be further increased.

  Further, as shown in FIG. 7B, the power supply line 50 has a rectangular shape that repeats a positive first potential VH and a negative second potential VL at a predetermined cycle with respect to the potential Vcom of the common electrode 37. A wave may be input. When the negative second potential VL is input, since the pixel electrode 35A has a lower potential than the common electrode 37 in FIGS. 6C and 6E, the black particles 26 are converted into the pixel electrode 35A. The white particles 27 try to move to the common electrode 37 side. Then, since the force that separates the white particles 27 and the black particles 26 that are colliding and pushing each other acts, the black particles 26 and the white particles 27 can be more smoothly passed and a high-speed optical response can be obtained. Obtainable.

  In the driving method of the present embodiment, the potential waveform input to the power supply line 50 is not limited to the rectangular wave shown in FIG. For example, a sine wave may be input to the power line 50, or a triangular wave or a sawtooth wave may be used. When any waveform is input, the display state of the pixel 40 can be changed while repeating the movement and stoppage of the black particles 26 and the white particles 27 as shown in FIG. can get.

  Further, the behavior of the black particles 26 and the white particles 27 in the electrophoretic element 32 also changes depending on the temperature of the electrophoretic display device 100. This is because the ease of movement of the black particles 26 and the white particles 27 changes as the viscosity of the dispersion medium constituting the electrophoretic element 32 changes. Therefore, also in the driving method of the present embodiment, it is preferable to change the period, duty, amplitude, etc. of the waveform input to the power supply line 50 according to the temperature (or environmental temperature) of the electrophoretic display device 100. Thereby, the slowing of the optical response speed resulting from a temperature change can also be suppressed.

[Halftone display drive method]
In the electrophoretic display device 100 of the present embodiment, halftone display can also be performed in each pixel 40. FIG. 8 is a timing chart showing a first halftone display driving method for performing halftone display in the electrophoretic display device 100. FIG. 9 is a timing chart showing the second halftone display driving method.

First, the first halftone display driving method will be described with reference to FIG.
As shown in FIG. 8, in order to perform halftone display by the electrophoretic display device 100, the halftone display step S200 including the image signal input step S201 and the subsequent image display step S202 is repeated a plurality of times. For example, by repeating eight halftone display steps S200 to display one image on the display unit 5, an arbitrary pixel 40 is controlled with eight or more gradation levels.

  The operation of the display unit 5 in the image signal input step S201 is to write an image signal in the storage capacitor C1 of the pixel 40 by the scanning line drive circuit 61 and the data line drive circuit 62, as in the image signal input step S101 of the previous embodiment. As for the operation, in the case of halftone display, switching is performed not to drive the pixel 40 in the halftone display step 200 but to an image signal of a level corresponding to the gradation of the pixel 40 to be finally displayed. An image signal (on / off signal) is input.

  In the image display step S202, as in the image display step S102 according to the previous embodiment, a rectangular wave that periodically repeats the first potential and the second potential is input to the power supply line 50. Then, the rectangular wave is input from the power supply line 50 to the pixel electrode 35 via the drive transistor TRd turned on based on the image signal input in the image signal input step S201, and the electrophoretic element 32 is driven. . However, the period of the image display step S202 is shorter than the period of the image display step S102 of the previous embodiment. For example, when a desired image is displayed by eight halftone display steps 200, the length is about 1/8 of the image display step S102.

  Also in the image display step S202 of the present driving method, as in the previous embodiment, the rectangular wave is supplied so that the first potential and the second potential are supplied to the pixel 40 at least once during the period. Adjust the period and duty. Thereby, a high-speed optical response can be obtained similarly to the previous embodiment.

  Each pixel 40 can be displayed with a desired gradation by making the selection operation of driving / stopping the pixel 40 in the image signal input step S201 different in each halftone display step S200. Hereinafter, this operation will be described in more detail.

  As illustrated in FIG. 8, the on-pixel voltage is input to the pixels 40 belonging to the scanning line 66 of the first row (Y1) in all three image signal input steps S201. On the other hand, for the pixels 40 belonging to the scanning line 66 of the second row (Y2), the on-pixel voltage is input in the first and second image signal input step S201, but in the third image signal input step S201. Input off-pixel voltage. Further, for the pixels 40 belonging to the m-th row (Ym), the on-pixel voltage is input only in the first image signal input step S201, and the off-pixel voltage is input in the subsequent image signal input step S201.

  When the display unit 5 is driven as described above, if the gradation level of the pixel 40 belonging to the first row is 3, the gradation level of the pixel 40 belonging to the second row is 2 and the pixel belonging to the m-th row. The gradation level of 40 is 1, and the pixels 40 belonging to each row are displayed with different gradations.

  As described above, according to the first halftone display driving method, the driving transistor TRd of the pixel 40 is turned on in the first frame in the driving method of displaying an image by inputting an image signal and displaying an image over a plurality of frames. In the second frame after the first frame, the driving transistor TRd of the pixel 40 is turned off, so that the length between the first frame and the second frame (in the electrophoretic element 32) The length of the period during which the voltage is applied is adjusted, whereby the gradation of the pixel 40 can be controlled.

  Although FIG. 8 shows that the length of the first image display step S202 and the length of the second image display step S202 are the same (both are 5 cycles), a plurality of halftone display steps S200 are shown. The length of the image display step S202 can be arbitrarily set. For example, the length of the image display step S202 may be adjusted so that the amount of change in the reflectance (density) of the electrophoretic element 32 is uniform in each halftone display step S200. Thereby, the controllability of halftone can be improved.

  In the example shown in FIG. 8, after the drive transistor TRd is turned on in the first halftone display step S200, the drive transistor TRd is continuously turned on until the drive transistor TRd is turned off. Although it is in a state, it is not limited to this. For example, the driving transistor TRd may be switched on, off, on, off in order from the first halftone display step S200. That is, the electrophoretic element 32 may be driven in the first and third halftone display steps S200 and may not be driven otherwise. With such a driving method, the gradation can be controlled more finely. Furthermore, the combination of driving methods that vary the length of the image display step S202 for each halftone display step S200 can significantly extend the gradation control range.

Next, the second halftone display driving method will be described with reference to FIG.
In the driving method shown in FIG. 9, a plurality of halftone display steps S300 are executed in a period during which one image is displayed. In the halftone display step S300, the scanning line 66 is sequentially selected by the scanning line driving circuit 61, and an image signal (on pixel voltage, off pixel voltage) for turning on / off the driving transistor TRd from the data line driving circuit 62 is supplied to the pixel 40. It is written in the storage capacitor C1. Further, in parallel with the image signal input, a rectangular wave that periodically repeats the first potential and the second potential is input to the power supply line 50. That is, the electrophoretic element 32 is driven simultaneously with the input of the image signal to the pixel 40 to display the image on the display unit 5.

  Also in this driving method, the display gradation of the pixel 40 can be freely controlled by arbitrarily controlling on / off of the driving transistor TRd in each halftone display step S300. In the example shown in FIG. 9, in the halftone display step S300 three times, in the pixels 40 belonging to the scanning line 66 of the first row (Y1), image signals for sequentially turning on, on, and on the drive transistor TRd are input. Image signals for sequentially turning on, turning on, and off the driving transistor TRd are input to the pixels 40 belonging to the scanning line 66 of the second row (Y2), and the driving transistors are applied to the pixels 40 belonging to the scanning line 66 of the m-th row. An image signal for turning TRd on, off, and off in order is input. Accordingly, each pixel 40 can be displayed at an arbitrary gradation in the same manner as the driving method shown in FIG.

According to the second halftone display driving method, an image signal is input to the pixel 40 in a state where a rectangular wave is input to the power line 50. Therefore, it is not necessary to separately provide a period for image signal input, and the time required for image display can be shortened as compared with the first halftone display driving method.
Also in the second halftone display driving method, as in the first halftone display driving method, any halftone display step S300 is selected from the plurality of halftone display steps S300 and the drive transistor TRd is turned on. It can be turned off. Further, the length of each halftone display step S300 can be arbitrarily changed.
In this driving method, the period of the rectangular wave input to the power supply line 50 is made shorter than the frame period of the display unit 5. By inputting such a rectangular wave, the first potential and the second potential are always input to the pixel electrode 35 at least once while the image signal is updated, thereby obtaining a high-speed optical response. Can

  Further, in any of the first and second halftone display driving methods, the waveform according to the modification shown in FIGS. 7A and 7B can be applied. Furthermore, a sine wave, a triangular wave, or a sawtooth wave may be used instead of the rectangular wave.

(Second Embodiment)
Next, an electrophoretic display device according to a second embodiment will be described with reference to FIG.
The electrophoretic display device 120 of this embodiment is characterized in that it includes a common power supply modulation circuit 64 that can supply a potential to the power supply line 50 in conjunction with the selection operation of the scanning line 66.

FIG. 10 is a diagram illustrating a main part of the electrophoretic display device 120 according to the second embodiment.
As shown in FIG. 10, the common power supply modulation circuit 64 according to the present embodiment includes a power supply line control circuit 150a provided corresponding to the scanning line 66 of each row. A power supply line 91 (potential Vdd) and a control line 92 (potential Sel) are connected to each power line control circuit 150a.

  The power supply line control circuit 150a includes a first transistor TR1, a second transistor TR2, and a capacitor C2. The gate of the first transistor TR1 is connected to the scanning line 66, the source is connected to the control line 92, and the drain is connected to the capacitor C2 and the gate of the second transistor TR2. The source of the second transistor is connected to the power supply line 91, and the drain is connected to the power supply line 50 in the row corresponding to the scanning line 66.

The power supply line control circuit 150a having the above configuration switches the connection of the power supply line 91 to the power supply line 50 by the first transistor TR1 and the second transistor TR2.
Specifically, when displaying an image on the display unit 5, a rectangular wave to be supplied to the pixel 40 is input to the power supply line 91, and the ON voltage that turns on the second transistor TR <b> 2 to the control line 92. An image signal is input to the pixel 40 in a state where Von is input. First, when a selection signal is input to the scanning line 66 by the scanning line driving circuit 61, the first transistor TR1 is turned on together with the control transistor TRc of the pixel 40, and the potential of the control line 92 (on voltage Von) is set to the capacitor C2. And input to the gate of the second transistor TR2. As a result, the second transistor TR2 is turned on, and the power supply line 91 and the power supply line 50 are connected, whereby a rectangular wave is input from the power supply line 91 to the power supply line 50, and the pixel 40 belonging to the selected row is input. Supplied.
When the selection period of the scanning line 66 ends, the first transistor TR1 shifts to an off state. However, since the holding voltage of the capacitor C2 is continuously supplied to the gate of the second transistor TR2, the on state of the second transistor TR2 is held. The rectangular wave continues to be supplied to the power line 50.
With the above operation, the pixels 40 can be displayed with gradation based on the image signal.

On the other hand, in order to stop the supply of the rectangular wave to the power supply line 50, the drive stop step S103 of the previous embodiment is executed in a state where the off voltage Voff for turning off the second transistor is input to the control line 92. .
Then, the first transistor TR1 is turned on by the selection operation of the scanning line 66, whereby the potential of the control line 92 (off voltage Voff) is input to the capacitor C2 and the gate of the second transistor TR2, and the second transistor TR2 is turned off. It becomes a state. Thereby, the power supply line 91 and the power supply line 50 are electrically disconnected. Even when the selection period of the scanning line 66 ends, the off state of the second transistor TR2 is maintained by the holding voltage of the capacitor C2.

  In the electrophoretic display device 120 of the present embodiment having the above configuration, the supply / stop of the rectangular wave to the pixels 40 in each row can be switched in conjunction with the selection operation of the scanning line 66. Such a configuration is particularly suitable when the display unit 5 is partially rewritten. In the partial rewriting of the display, by selecting only the scanning line 66 connected to the pixel 40 whose display is to be updated, an image signal is input only to a part of the pixels 40 of the display unit 5. In such partial rewriting, supplying a power waveform to the pixel 40 whose display is not updated is a waste of power. Therefore, if the common power supply modulation circuit 64 of this embodiment is employed, the supply of the power supply waveform to the power supply line 50 is started only when the selection signal is input to the scanning line 66. Wasteful power consumption does not occur.

[Modification]
FIG. 11 is a diagram illustrating a modification of the electrophoretic display device according to the second embodiment.
The common power supply modulation circuit 64 of the electrophoretic display device 120A shown in FIG. 11 includes a power supply line control circuit 150b provided corresponding to the scanning line 66 of each row. A power supply line 91 (Vdd), a control line 92 (Sel), an inversion control line 93 (Selb), and a second power supply line 94 (Vo) are connected to the power supply line control circuit 150b. .

  The power supply line control circuit 150b includes a first transistor TR1, a second transistor TR2, a capacitor C2, a third transistor TR3, a fourth transistor TR4, and a capacitor C3. A circuit including the first transistor TR1, the second transistor TR2, and the capacitor C2 is the same as the power supply line control circuit 150a illustrated in FIG. The gate of the third transistor TR3 is connected to the scanning line 66, the source is connected to the inversion control line 93, and the drain is connected to the capacitor C3 and the gate of the fourth transistor TR4. The source of the fourth transistor is connected to the second power supply line 94, and the drain is connected to the power supply line 50.

In the power supply line control circuit 150b having the above-described configuration, the potential Sel of the control line 92 and the potential Selb of the inversion control line 93 are turned on to turn on the second transistor TR2 and the fourth transistor TR4 and turned off. One of the voltages Voff is used. When the potential Sel of the control line 92 is the on-voltage Von, the potential Selb of the inversion control line 93 is the off-voltage Voff, and when the potential Sel of the control line 92 is the off-voltage Voff, the inversion control is performed. The potential Selb of the line 93 becomes the ON voltage Von. The potential Vo of the second power supply line 94 is the potential Vcom of the common electrode 37.
Here, when a selection signal is input to the scanning line 66, the first transistor TR1 and the third transistor TR3 are simultaneously turned on. At this time, the on-voltage Von is input to the gates of the capacitor C2 and the second transistor TR2 as the potential Sel of the control line 92 via the first transistor TR1, while the gates of the capacitor C3 and the fourth transistor TR4 are input to the gates of the second transistor TR2. The off voltage Voff is input as the potential Selb of the inversion control line 93 through the three transistor TR3.

  In the power supply line control circuit 150b of this example, when the pixel 40 is driven to display an image using the above-described operation, an on voltage Von is applied to the control line 92 and an off voltage Voff is applied to the inversion control line 93. When the input and the driving of the pixel 40 are stopped, the off voltage Voff is input to the control line 92 and the on voltage Von is input to the inversion control line 93.

Then, during the image display operation, the ON voltage Von is input from the control line 92 to the gate of the second transistor TR2 via the first transistor TR1, and the inversion control line to the gate of the fourth transistor TR4 via the third transistor TR3. Since the off voltage Voff is input from 93, the second transistor TR2 is turned on, the fourth transistor TR4 is turned off, and a rectangular wave is supplied to the power supply line 50 from the power supply line 91 via the second transistor TR2. Is done.
On the other hand, when stopping the driving of the pixel, contrary to the above, the second transistor TR2 is turned off and the fourth transistor TR4 is turned on, and the power line 50 is connected to the second transistor TR4 via the fourth transistor TR4. The potential of the power supply line, that is, the same potential (0 V) as that of the common electrode 37 is input.

  In the electrophoretic display device 120 of the previous second embodiment, the power supply line 50 is in a high impedance state in order to turn off the second transistor TR2 when driving of the pixel 40 is stopped. In the high-impedance power supply line 50, the potential fluctuates with potential fluctuations in the surrounding wiring and the like, so that the potential of the pixel electrode 35 changes to cause display unevenness and electrostatic breakdown of the drive transistor TRd. There is a risk of

  On the other hand, in the electrophoretic display device 120A according to the modification, the potential of the second power supply line 94 is input to the power supply line 50 via the fourth transistor TR4 when the driving of the pixel 40 is stopped. The power supply line 50 can be prevented from entering a high impedance state. Therefore, according to the electrophoretic display device of this example, it is possible to prevent the above-described display unevenness and electrostatic breakdown.

(Third embodiment)
Next, an electrophoretic display device according to a third embodiment will be described with reference to FIG.
FIG. 12 is a diagram illustrating a part of the display unit of the electrophoretic display device according to the third embodiment. FIG. 13 is a diagram illustrating a potential waveform supplied to the power supply line.

  In the display unit of the electrophoretic display device 130 illustrated in FIG. 12, a plurality of pixels 40A and pixels 40B are arranged in a checkered pattern. That is, the pixels 40A and the pixels 40B are alternately arranged in the row direction and the column direction. The circuit configurations of the pixel 40A and the pixel 40B are the same as those of the pixel 40 according to the first embodiment, but are connected to different power supply lines. Specifically, the first power supply line 50A (potential Vdda) is connected to the source of the drive transistor TRd of the pixel 40A, and the source of the drive transistor TRd of the pixel 40B is a system different from that of the first power supply line 50A. The second power supply line 50B (potential Vddb) is connected. As shown in FIG. 13, the rectangular wave supplied to the first power supply line 50 </ b> A (Vdda) and the rectangular wave supplied to the second power supply line 50 </ b> B (Vddb) have different phases from each other. It is said that.

  In the electrophoretic display device 130 of the present embodiment having the above-described configuration, when displaying an image on the display unit, the pixel electrodes 35 have different potentials between the adjacent pixels 40A and 40B. That is, during the period in which the pixel electrode 35 of the pixel 40A is at the first potential, the pixel electrode 35 of the adjacent pixel 40B is at the second potential. Then, a horizontal electric field is formed between the pixel electrode 35 of the pixel 40 </ b> A and the pixel electrode 35 of the pixel 40 </ b> B, and the electric field acts on the black particles 26 and the white particles 27.

  In particular, in the pixel 40B in which the pixel electrode 35 is at the second potential, the black particles 26 and the white particles 27 stop moving in the thickness direction of the electrophoretic element 32. Easy to receive. Therefore, in the pixel 40B, the black particles 26 and the white particles 27 can be smoothly passed by performing the action of separating the black particles 26 and the white particles 27 in the collision state by the horizontal electric field. High speed optical response can be obtained.

  FIG. 12 shows the case where the pixels 40A and the pixels 40B are arranged in a checkered pattern, but the four pixels 40A are arranged in two rows and two columns, and the four pixels 40B are arranged in two rows and two columns. Those arranged in a row may be used as structural units, and they may be arranged in a checkered pattern. That is, every two pixels 40A and 40B may be alternately arranged in the row direction and the column direction. Alternatively, one or two rows of pixels 40A and one or two rows of pixels 40B may be alternately arranged, and one or two columns of pixels 40A and one or two columns of pixels 40B. And may be arranged alternately. That is, if the pixels 40B are arranged adjacent to each other in at least one direction of the four sides of one pixel 40A, a horizontal electric field can be generated between the pixel electrodes 35, and the above-described effects can be obtained. .

(Electronics)
Next, a case where the electrophoretic display device according to the embodiment and the electrophoretic display device according to the modification are applied to an electronic device will be described.
FIG. 14 is a front view of the wrist watch 1000. The wrist watch 1000 includes a watch case 1002 and a pair of bands 1003 connected to the watch case 1002.
On the front surface of the watch case 1002, a display unit 1005 including the electrophoretic display device of each of the above embodiments, a second hand 1021, a minute hand 1022, and an hour hand 1023 are provided. On the side surface of the watch case 1002, a crown 1010 and an operation button 1011 are provided as operation elements. The crown 1010 is connected to a winding stem (not shown) provided inside the case, and is integrally provided with the winding stem so that it can be pushed and pulled in multiple stages (for example, two stages) and can be rotated. . The display unit 1005 can display a background image, a character string such as date and time, or a second hand, a minute hand, and an hour hand.

  FIG. 15 is a perspective view illustrating a configuration of the electronic paper 1100. An electronic paper 1100 includes the electrophoretic display device of the above embodiment in a display area 1101. The electronic paper 1100 is flexible and includes a main body 1102 made of a rewritable sheet having the same texture and flexibility as conventional paper.

  FIG. 16 is a perspective view showing the configuration of the electronic notebook 1200. An electronic notebook 1200 is obtained by bundling a plurality of the electronic papers 1100 and sandwiching them between covers 1201. The cover 1201 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.

According to the wristwatch 1000, the electronic paper 1100, and the electronic notebook 1200 described above, the electrophoretic display device according to the present invention is employed, so that the electronic device includes display means capable of switching display at high speed.
In addition, said electronic device illustrates the electronic device which concerns on this invention, Comprising: The technical scope of this invention is not limited. For example, the electro-optical device according to the present invention can be suitably used for a display portion of an electronic device such as a mobile phone or a portable audio device.

  DESCRIPTION OF SYMBOLS 5 ... Display part, 32 ... Electrophoretic element, 35, 35A, 35B ... Pixel electrode, 40, 40A, 40B ... Pixel, 63 ... Controller (control part, control circuit), 66 ... Scanning line, 68 ... Data line, 100 , 120, 120A, 130 ... electrophoretic display device, TRc ... control transistor, TRd ... drive transistor, S101 ... image signal input step (image signal input period), S102 ... image display step (image display period), S103 ... drive stop Step

Claims (13)

An electrophoretic element is sandwiched between a pair of substrates, and a display portion in which a plurality of pixels are arranged is provided. The pixel includes a control transistor, a memory element connected to a drain of the control transistor, and a drain of the control transistor A driving method for an electrophoretic display device, comprising: a driving transistor having a gate connected thereto; a pixel electrode connected to a drain of the driving transistor; and a counter electrode facing the pixel electrode through the electrophoretic element Because
In an image display period in which the pixels are driven to display an image on the display unit,
A driving method of an electrophoretic display device, wherein a first potential and a second potential different from each other are input at least once to the source of the driving transistor.   The method of driving an electrophoretic display device according to claim 1, wherein the first potential and the second potential have opposite polarities to the potential of the counter electrode.   2. The electrophoresis according to claim 1, wherein a difference between one of the first potential and the second potential and the potential of the counter electrode is equal to or lower than a threshold voltage of the electrophoretic element. A driving method of a display device.   4. The electricity according to claim 1, wherein a potential waveform that periodically repeats the first potential and the second potential is input to a source of the driving transistor. 5. Driving method of electrophoretic display device.   The first period in which the first potential is input to the source of the driving transistor and a second period in which the second potential is input have different lengths. The driving method of the electrophoretic display device according to any one of 1 to 4.   6. The potential waveform having a phase different from each other is input to each of the drive transistors of each of the two pixels adjacent to each other in the row direction or the column direction in the display unit. A driving method for an electrophoretic display device according to claim 1. A plurality of scanning lines and a plurality of data lines extending in directions intersecting each other are formed on the display portion, and the plurality of pixels are provided at positions corresponding to intersections of the plurality of scanning lines and the plurality of data lines. And
When the period for sequentially selecting the plurality of scanning lines once is one frame,
An image signal for shifting the driving transistor to the on state in the first frame is input to the pixel, and an image signal for shifting the driving transistor to the off state in the second frame after the first frame is input to the pixel. The method for driving an electrophoretic display device according to claim 1, wherein the input is performed on a pixel.   8. The driving method of the electrophoretic display device according to claim 7, wherein display gradation of the pixel is controlled according to a length of a period from the first frame to the second frame. An image signal input period in which the image signal is input to the pixel in a state where a potential substantially the same as the potential of the counter electrode is input to the source of the driving transistor, and the image display period following the image signal input period Display the image on the display unit by repeating the unit display period multiple times,
The driving method of the electrophoretic display device according to claim 7, wherein an on / off state of the driving transistor in the corresponding image display period is selected by an image signal input to the pixel in the image signal input period.   During the image display period, the operation of inputting the image signal to the pixel is performed over a plurality of frames, and the drive transistor is turned on in the image display period by the image signal input to the pixel for each frame. The driving method of the electrophoretic display device according to claim 7, wherein a length of a period to be set is set. An electrophoretic element is sandwiched between a pair of substrates, and a display portion in which a plurality of pixels are arranged is provided. The pixel includes a control transistor, a memory element connected to a drain of the control transistor, and a drain of the control transistor A driving transistor having a gate connected thereto, a pixel electrode connected to the drain of the driving transistor, and a counter electrode facing the pixel electrode through the electrophoretic element, and driving and controlling the display unit An electrophoretic display device having a control unit,
The controller is
A first potential and a second potential different from each other are input to the source of the driving transistor at least once during an image display period in which the pixel is driven to display an image on a display unit. An electrophoretic display device. An electrophoretic element is sandwiched between a pair of substrates, and the display unit is formed by arranging a plurality of pixels. The pixel includes a control transistor, a memory element connected to the drain of the control transistor, Electrophoresis provided with a drive transistor having a gate connected to the drain of the control transistor, a pixel electrode connected to the drain of the drive transistor, and a counter electrode facing the pixel electrode through the electrophoretic element A control circuit applicable to a display device,
A first potential and a second potential different from each other are input to the source of the driving transistor at least once during an image display period in which the pixel is driven to display an image on a display unit. A control circuit for an electrophoretic display device.   An electronic apparatus comprising the electrophoretic display device according to claim 11.

Images