JP2011158802A - Electrophoretic display device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise when displaying halftone in an electrophoresis display device and to realize high quality display. <P>SOLUTION: According to total duration time (Ta1, Ta2) of at least one driving voltage pulse (Pa1, Pa2) applied to an electrophoresis element (23) of a pixel (20) in a first display state (for example, white), the halftone between the first display state and a second display state (for example, black) is selected, and in a state where a data signal supplied from a data line (Xd1, Xd2) is held at a memory circuit (25), a potential of a first control line (95), a potential of a second control line (94) and a common potential (Vcom) are inverted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to the technical fields of electrophoretic display devices and electronic devices.

  In this type of electrophoretic display device, in each of a plurality of pixels, by applying a voltage to an electrophoretic element including, for example, white and black electrophoretic particles sandwiched between a pixel electrode and a common electrode, the electrophoretic particles Move the to display the image. Further, by changing the time during which the voltage is applied to the electrophoretic element in each pixel, a halftone (for example, gray) is displayed.

  On the other hand, as an electrophoretic display device of this type, a pixel circuit (hereinafter referred to as a thin film transistor (TFT)) that includes a pixel switching element, a memory circuit (for example, SRAM: Static Random Access Memory), and a switch circuit (hereinafter referred to as a thin film transistor). And “9T pixel circuit” as appropriate). Although the configuration and operation will be described in detail later, in the 9T type pixel circuit, the time for applying the voltage to the electrophoretic element is adjusted while the data signal is supplied to and held in the memory circuit via the pixel switching element. To do.

  For example, in Patent Document 1, when switching display colors in an electrophoretic display device, non-uniform color display is avoided by changing the drive voltage application time according to the continuous display time of the display color before switching. Techniques to do this are disclosed.

JP 2007-79170 A

  In this type of electrophoretic display device, there is a technical problem that, when displaying a halftone, noise may occur in the display due to manufacturing variations of pixel circuits provided in each pixel. .

  For example, in a 9T type pixel circuit, one of the first and second control lines is exclusively selected by the switch circuit based on the data signal held in the memory circuit, and is electrically connected to the pixel electrode. . Due to the manufacturing variation of the transistors constituting the switch circuit between the pixels, the value of the electrical resistance between each of the first and second control lines and the electrophoretic element also varies. The applied voltage varies. As a result, there is a technical problem in that different halftones may be displayed between pixels that should display the same halftone. In particular, noise in displaying such halftones tends to be more prominent as the time for applying the drive voltage to display halftones is shorter.

  The present invention has been made in view of, for example, the above-described problems. An electrophoretic display device capable of reducing noise when displaying a halftone and performing high-quality display, and the electrophoretic display device are provided. It is an object to provide an electronic device provided.

  In order to solve the above problems, an electrophoretic display device according to the present invention is provided corresponding to the intersection of a scanning line and a data line, and includes a first electrode, a second electrode, the first electrode, and the second electrode. An electrophoretic display device including a plurality of pixels including an electrophoretic element including an electrophoretic particle sandwiched between electrodes, a pixel switching element, and a memory circuit, wherein the first control line, the first control line, 2, a switch circuit provided in the pixel, and a potential control unit, wherein the pixel switching element is provided between an input terminal of the memory circuit and the data line, and the switch The circuit is provided between the output terminal of the memory circuit and the first electrode, the connection state between the first control line and the first electrode, the second control line, the first electrode, The connection state of the data is the data supplied from the data line. The potential control unit controls the potential supplied to the first control line to the second control line between the first potential and the second potential. The potential to be supplied is switched between the first potential and the second potential, and the potential to be supplied to the second electrode is switched between the third potential and the fourth potential, and the potential of the first electrode is changed. When the potential of the second electrode is higher than the potential of the second electrode, the potential difference generated between the first electrode and the second electrode is positive, and the display voltage of the pixel is different from the positive voltage and the positive polarity. A first display state is selected by applying one of a negative voltage and the negative voltage to the electrophoretic element, and the other of the positive voltage and the negative voltage is different from the one voltage. Second display state by applying voltage to the electrophoretic element Depending on the total duration of at least one drive voltage pulse applied to the electrophoretic element of the selected pixel in the first display state, an intermediate between the first display state and the second display state The voltage applied to the first control line, the second control line, and the second electrode in a state in which the key is selected and the data signal supplied from the data line is held in the memory circuit Are reversed.

  According to the electrophoretic display device of the present invention, a 9T type pixel circuit is provided, and the switch circuit has a first switching circuit based on a data signal supplied from a data line via the pixel switching element and held in the memory circuit. In addition, electrical connection between the second control line and the first electrode (for example, a pixel electrode) is controlled. The potential control unit switches the first and second control lines to the first and second potentials, respectively. The potential of the first electrode (for example, pixel electrode) is switched corresponding to the first or second potential supplied from the first or second control line. On the other hand, the second electrode (for example, the common electrode) is switched to each of the third and fourth potentials by the potential control unit. A voltage corresponding to the potential difference between the first electrode and the second electrode is applied to the electrophoretic element. When the potential of the first electrode is higher than the potential of the second electrode, a positive voltage is applied to the electrophoretic element, and when the potential of the second electrode is higher than the potential of the first electrode, A negative voltage is applied to the electrophoretic element. As a result, the electrophoretic element is driven, and the first and second display states are selected.

  In the present invention, by applying at least one drive voltage pulse to the electrophoretic element to a pixel in the first display state (for example, white), a halftone (that is, an intermediate gradation, for example, gray) is displayed on the pixel. At this time, when one driving voltage pulse is applied to the pixel, a potential difference corresponding to a predetermined duration occurs between the first electrode and the second electrode. Therefore, when a plurality of driving voltage pulses are applied to the pixel, a potential difference is generated between the first electrode and the second electrode in accordance with the total duration obtained by adding the durations of the plurality of driving voltage pulses.

  In a state where such a potential difference is generated between the first electrode and the second electrode, the present invention inverts the voltages applied to the first control line, the second control line, and the second electrode, respectively. . That is, when displaying a halftone, first, at least one drive voltage pulse is applied to a pixel in the first display state. At this time, typically, at least one drive voltage pulse is applied to the pixel in the first display state so that the pixel is closer to the second display state than the halftone to be displayed. That is, the electrophoretic particles included in the electrophoretic layer move between the first and second electrodes in the pixel in the first display state, and the pixel is displayed closer to the second display state than the halftone to be displayed. A voltage is applied between the first and second electrodes for a total duration of at least one drive voltage pulse so as to be in a state (eg, gray closer to black than gray to be displayed).

  Next, the voltages applied to the first control line, the second control line, and the second electrode are inverted to the pixels in the display state closer to the second display state than the halftone to be displayed, respectively. To do. As a result, the voltage applied between the first and second electrodes is also inverted, and the pixels that are in the display state closer to the second display state than the halftone to be displayed are brought closer to the halftone to be displayed. In other words, by reversing the voltage applied according to the total duration of at least one drive voltage pulse to a pixel that is in a display state closer to the second display state than the halftone to be displayed, The display state is returned to the halftone to be displayed on the first display state side. Note that when the voltages applied to the first control line, the second control line, and the second electrode are inverted, at least one drive voltage pulse is applied to the second half of the halftone to be displayed. A pixel in a display state close to the display state is in a state where a data signal is held in the memory circuit.

  When displaying halftone as described above, a voltage corresponding to at least one drive voltage pulse is applied between the first and second electrodes, and then inverted to provide each pixel. The noise on the display due to the manufacturing variation of the pixel circuit can be reduced or eliminated (that is, it is possible to reduce the display of different halftones between pixels that should display the same halftone). ). That is, according to the electrophoretic display device according to the present invention, for example, compared to a case where halftone is displayed on the pixel by applying only at least one drive voltage pulse to the pixel where halftone is to be displayed, Since the time for applying the voltage between the first and second electrodes can be lengthened, as described above, the noise (that is, the halftone is displayed) that tends to be more prominent as the time for applying the drive voltage is shorter. Noise) can be effectively reduced or eliminated. As a result, high-quality display can be performed.

  As described above, according to the electrophoretic display device of the present invention, it is possible to reduce noise when displaying a halftone and to perform high-quality display.

  In one aspect of the electrophoretic display device according to the present invention, an inversion duration for maintaining a state in which voltages applied to the first control line, the second control line, and the second electrode are inverted. Is shorter than the total duration of the at least one drive voltage pulse.

  According to this aspect, for example, the halftone can be displayed quickly compared to the case where the inversion duration is longer than the total duration of the drive voltage pulse of at least one (that is, the halftone to be displayed is displayed). Can reduce the time required to display). Furthermore, it is possible to suppress power consumption required to apply voltages to the first and second control lines and the second electrode, respectively.

  In another aspect of the electrophoretic display device according to the present invention, inversion sustaining maintains a state in which voltages applied to the first control line, the second control line, and the second electrode are inverted. The time is longer than the total duration of the at least one drive voltage pulse.

  According to this aspect, for example, when the voltage of the other of the positive polarity and the negative polarity is applied between the first and second electrodes, the electrophoretic particles contained in the electrophoretic layer are Even if it is difficult to move, the halftone to be displayed can be reliably displayed by inverting the voltages applied to the first and second control lines and the second electrode.

  The inversion duration may be set based on, for example, the characteristics of the electrophoretic particles included in the electrophoretic layer (for example, ease of movement of the electrophoretic particles).

  In another aspect of the electrophoretic display device according to the present invention, after all the at least one drive voltage pulse is applied, the first control line, the second control line, and the second electrode are applied. Each voltage is inverted.

  According to this aspect, for example, when the drive voltage pulse of at least one drive voltage pulse is applied, the voltages applied to the first and second control lines and the second electrode are respectively inverted. The halftone can be displayed promptly (that is, the time required to display the halftone to be displayed can be shortened). Furthermore, it is possible to suppress power consumption required to apply voltages to the first and second control lines and the second electrode, respectively.

  In another aspect of the electrophoretic display device according to the invention, the first control line, the second control line, and the first control line are selected for the pixels for which the first or second display state is selected. The polarity of the voltage between the first and second electrodes based on the voltage applied to the two electrodes is not reversed.

  According to this aspect, each of the pixels for which the first and second display states are selected can be reliably set to the first or second display state, respectively.

  That is, in this aspect, when a pixel in the first display state (for example, white) is set to the second display state (for example, black), only the driving voltage pulse is applied to the pixel, and then the first And the polarity of the voltage between the second electrodes is not reversed. Therefore, it is possible to prevent a pixel that should be in the second display state from becoming a display state (for example, black that is close to white) closer to the first display state than the second display state.

  On the other hand, the pixel in the first display state is maintained in this state, and the polarity of the voltage between the first and second electrodes is not inverted. Therefore, it is possible to prevent a pixel that should be in the first display state from becoming a display state closer to the second display state than in the first display state.

  In another aspect of the electrophoretic display device according to the present invention, the drive voltage pulse is a first drive voltage pulse, and the first drive voltage pulse is inverted in a pixel in the second display state. In addition to applying two driving voltage pulses, and applying the first and second driving voltage pulses, the voltages applied to the first control line, the second control line, and the second electrode are respectively Invert.

  According to this aspect, similarly to the case where at least one drive voltage pulse is applied to the pixel in the first display state as described above, the pixel in the second display state is typically replaced with at least one second By applying the drive voltage pulse, the halftone to be displayed is returned to the second display state side in a state closer to the first display state than the halftone to be displayed.

  At this time, the pixel to which the first drive voltage pulse is applied and the pixel to which the second drive voltage pulse is applied are based on the data signal when the pixel electrode is electrically connected to the first and second control lines. Different from each other. Accordingly, for each of the pixels to which the first driving voltage pulse and the second driving voltage pulse are applied, in addition to the application of the first driving voltage pulse and the second driving voltage pulse, the pixels should be displayed after applying them. When returning to the halftone, it is not necessary to change the electrical connection state of the pixel electrode with respect to the first and second control lines. Therefore, the supply of data signals via the data lines can be simplified, and halftones can be displayed easily and with high quality.

  In the embodiment described below (third embodiment), each of the first drive voltage pulse and the second drive voltage pulse may be simply referred to as “drive voltage pulse”.

  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 apparatus of the present invention, since the electrophoretic display device of the present invention described above is provided, high-quality display can be performed, for example, wristwatch, electronic paper, electronic notebook, mobile phone, mobile phone, etc. Various electronic devices such as audio equipment can be realized.

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

It is a block diagram which shows the whole structure of the electrophoretic display device which concerns on this embodiment. It is an equivalent circuit diagram which shows the electrical structure of a pixel. It is a fragmentary sectional view of the display part of the electrophoretic display device concerning this embodiment. It is a schematic diagram which shows the structure of a microcapsule. It is a schematic diagram which shows the display part of the electrophoretic display device of the state which displayed the example of the image containing a halftone. It is a conceptual diagram which shows one operation | movement of the electrophoretic display device which concerns on this embodiment. It is a conceptual diagram which shows the other operation | movement of the electrophoretic display apparatus which concerns on this embodiment. It is a flowchart which shows the outline | summary of operation | movement of the electrophoretic display apparatus which concerns on this embodiment. 6 is a timing chart for explaining an operation example of the electrophoretic display device of the first embodiment. It is explanatory drawing which shows roughly the operation | movement by the normal black drive in the pixel which should display gray. It is explanatory drawing which shows roughly the operation | movement by the inversion white drive in the pixel which should display gray. 10 is a timing chart for explaining an operation example of the electrophoretic display device of the second embodiment. It is a timing chart (the 1) for explaining an example of operation of an electrophoretic display device of a 3rd embodiment. It is a timing chart (2) for demonstrating the operation example of the electrophoretic display device of 3rd Embodiment. It is a perspective view which shows the structure of the electronic paper which is an example of the electronic device to which the electrophoretic display apparatus is applied. It is a perspective view which shows the structure of the electronic notebook which is an example of the electronic device to which an electrophoretic display apparatus is applied.

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

  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, an electrophoretic display device 1 according to the present embodiment includes a display unit 3, a scanning line driving circuit 60, and a data line driving circuit 70 as main components.

  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). The pixels 20 are arranged corresponding to the intersections of the m scanning lines 40 and the n data lines 50.

  The scanning line driving circuit 60 sequentially supplies a scanning signal in a pulse manner to each of the scanning lines Y1, Y2,..., Ym based on the timing signal. The data line driving circuit 70 supplies data signals to the data lines X1, X2,..., Xn based on the timing signal. The data signal takes a binary level of a high potential level (hereinafter referred to as “high level”) or a low potential level (hereinafter referred to as “low level”).

  Here, each pixel 20 is electrically connected to a high potential power line 91, a low potential power line 92, a common potential line 93, and first and second control lines 95 and 94. The high potential power supply line 91, the low potential power supply line 92, the common potential line 93, and the first and second control lines 95 and 94 are typically along the row direction (X direction) as shown in FIG. For each pixel column composed of the pixels 20 arranged in this manner, wiring is commonly made to the pixels 20 belonging to the pixel column.

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

  In FIG. 2, a pixel 20 includes a pixel switching transistor 24, a memory circuit 25, a switch circuit 110, a pixel electrode 21, a common electrode 22, an electrophoresis, which is an example of the “pixel switching element” according to the invention. An element 23 is provided.

  The pixel switching transistor 24 is configured by an N-type transistor as an example. The pixel switching transistor 24 has its gate electrically connected to the scanning line 40, its source electrically connected to the data line 50, and its drain electrically connected to the input terminal N 1 of the memory circuit 25. It is connected to the. The pixel switching transistor 24 is configured to pulse a data signal supplied from the data line driving circuit 70 (see FIG. 1) via the data line 50 via the scanning line 40 from the scanning line driving circuit 60 (see FIG. 1). Is output to the input terminal N1 of the memory circuit 25 at a timing corresponding to the scanning signal supplied to the memory circuit 25.

  The memory circuit 25 includes inverter circuits 25a and 25b as an example, and is configured as an SRAM (Static Random Access Memory).

  The inverter circuits 25a and 25b have a loop structure in which the other output terminal is electrically connected to the input terminals of each other. That is, the input terminal of the inverter circuit 25a and the output terminal of the inverter circuit 25b are electrically connected to each other, and the input terminal of the inverter circuit 25b and the output terminal of the inverter circuit 25a are electrically connected to each other. The input terminal of the inverter circuit 25a is configured as the input terminal N1 of the memory circuit 25, and the output terminal of the inverter circuit 25a is configured as the output terminal N2 of the memory circuit 25.

  The inverter circuit 25a has an N-type transistor 25a1 and a P-type transistor 25a2. The gates of the N-type transistor 25 a 1 and the P-type transistor 25 a 2 are electrically connected to the input terminal N 1 of the memory circuit 25. The source of the N-type transistor 25a1 is electrically connected to a low potential power supply line 92 to which a low potential power supply potential Vss is supplied. The source of the P-type transistor 25a2 is electrically connected to a high potential power supply line 91 to which a high potential power supply potential VEP is supplied. The drains of the N-type transistor 25 a 1 and the P-type transistor 25 a 2 are electrically connected to the output terminal N 2 of the memory circuit 25.

  The inverter circuit 25b has an N-type transistor 25b1 and a P-type transistor 25b2. The gates of the N-type transistor 25 b 1 and the P-type transistor 25 b 2 are electrically connected to the output terminal N 2 of the memory circuit 25. The source of the N-type transistor 25b1 is electrically connected to a low potential power supply line 92 to which a low potential power supply potential Vss is supplied. The source of the P-type transistor 25b2 is electrically connected to a high potential power supply line 91 to which a high potential power supply potential VEP is supplied. The drains of the N-type transistor 25 b 1 and the P-type transistor 25 b 2 are electrically connected to the input terminal N 1 of the memory circuit 25.

  The high potential power supply line 91 and the low potential power supply line 92 are configured to be able to supply the high potential power supply potential VEP and the low potential power supply potential Vss from the potential control unit 210, respectively. The electrical connection between each of the high potential power supply line 91 and the low potential power supply line 92 and the potential control unit 210 is controlled by the controller 10 switching each of the switches 91s and 92s between an on state and an off state.

  When a high level data signal is input to the input terminal N1, the memory circuit 25 outputs a low potential power supply potential Vss from the output terminal N2, and when a low level data signal is input to the input terminal N1. The high potential power supply potential VEP is output from the output terminal N2. That is, the memory circuit 25 outputs the low potential power supply potential Vss or the high potential power supply potential VEP depending on whether the input data signal is high level or low level. In other words, the memory circuit 25 is configured to be able to store the input data signal as the low potential power supply potential Vss or the high potential power supply potential VEP.

  The switch circuit 110 includes a first transmission gate 111 and a second transmission gate 112.

  The first transmission gate 111 includes a P-type transistor 111p and an N-type transistor 111n. The sources of the P-type transistor 111p and the N-type transistor 111n are electrically connected to the second control line 94. The drains of the P-type transistor 111p and the N-type transistor 111n are electrically connected to the pixel electrode 21. The gate of the P-type transistor 111p is electrically connected to the input terminal N1 of the memory circuit 25, and the gate of the N-type transistor 111n is electrically connected to the output terminal N2 of the memory circuit 25.

  The second transmission gate 112 includes a P-type transistor 112p and an N-type transistor 112n. The sources of the P-type transistor 112p and the N-type transistor 112n are electrically connected to the first control line 95. The drains of the P-type transistor 112p and the N-type transistor 112n are electrically connected to the pixel electrode 21. The gate of the P-type transistor 112p is electrically connected to the output terminal N2 of the memory circuit 25, and the gate of the N-type transistor 112n is electrically connected to the input terminal N1 of the memory circuit 25.

  The switch circuit 110 selectively selects one of the second control line 94 and the first control line 95 according to the data signal input to the memory circuit 25, and selects one of the control lines. The control line is electrically connected to the pixel electrode 21.

  Specifically, when a high level data signal is input to the input terminal N1 of the memory circuit 25, the low potential power supply potential Vss is output from the memory circuit 25 to the gates of the N-type transistor 111n and the P-type transistor 112p. Since the high-potential power supply potential VEP is output to the gates of the P-type transistor 111p and the N-type transistor 112n, only the P-type transistor 112p and the N-type transistor 112n constituting the second transmission gate 112 are turned on. The P-type transistor 111p and the N-type transistor 111n constituting one transmission gate 111 are turned off. On the other hand, when a low level data signal is input to the input terminal N1 of the memory circuit 25, the high potential power supply potential VEP is output from the memory circuit 25 to the gates of the N-type transistor 111n and the P-type transistor 112p, and the P-type By outputting the low-potential power supply potential Vss to the gates of the transistor 111p and the N-type transistor 112n, only the P-type transistor 111p and the N-type transistor 111n constituting the first transmission gate 111 are turned on, and the second transmission The P-type transistor 112p and the N-type transistor 112n constituting the gate 112 are turned off. That is, when a high level data signal is input to the input terminal N1 of the memory circuit 25, only the second transmission gate 112 is turned on, while a low level data signal is input to the input terminal N1 of the memory circuit 25. Is input, only the first transmission gate 111 is turned on.

  Each pixel electrode 21 of the plurality of pixels 20 is electrically connected to the first or second control line 94 or 95 that is alternatively selected according to the data signal by the switch circuit 110. At this time, the pixel electrode 21 of each of the plurality of pixels 20 is supplied with the first potential v1 or the second potential v2 or is in a high impedance state according to the on / off state of the switch 94s or 95s.

  More specifically, for the pixel 20 to which the low level data signal is supplied, only the first transmission gate 111 is turned on, and the pixel electrode 21 of the pixel 20 is electrically connected to the second control line 94. And the first or second potential v1 or v2 is supplied from the potential controller 210 in accordance with the on / off state of the switch 94s, or the high-impedance state is set. On the other hand, for the pixel 20 to which the high level data signal is supplied, only the second transmission gate 112 is turned on, and the pixel electrode 21 of the pixel 20 is electrically connected to the first control line 95, Depending on the on / off state of the switch 95s, the first or second potential v1 or v2 is supplied from the potential control unit 210, or a high impedance state is set.

  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.

  In the present embodiment, the potential controller 210 supplies the potential supplied to the second control line 94 between the first potential v1 and the second potential v2 between the first potential v1 and the second potential v2. The common potential Vcom is switched between the third potential v3 and the fourth potential v4 between the first potential v1 and the second potential v2. The electrical connection between each of the first and second control lines 95 and 94 and the common potential line 93 and the potential control unit 210 is such that the controller 10 determines whether each of the switches 93s, 94s and 95s is turned on or off. It is controlled by switching.

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

  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. Although not shown here on the element substrate 28, the pixel switching transistor 24, the memory circuit 25, the switch circuit 110, the scanning line 40, the data line 50, and the high potential power supply line 91 described above with reference to FIG. 2. A laminated structure in which the low potential power supply line 92, the common potential line 93, the second control line 94, the first control line 95, and the like are formed 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 21. 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 bonded to the element substrate 28 side where is formed by an adhesive layer 31.

  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 white particles 82 and the black particles 83 are examples of the “electrophoretic particles” according to the present invention.

  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, and gum arabic.

  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, cycloaliphatic 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.

  3 and FIG. 4, when a voltage is applied between the pixel electrode 21 and the common electrode 22 so that the potential of the common electrode 22 is relatively high, the positively charged black particles 83 are While being attracted to the pixel electrode 21 side in the microcapsule 80 by the Coulomb force, the negatively charged white particles 82 are attracted to the common electrode 22 side in the microcapsule 80 by the Coulomb force. As a result, the white particles 82 gather on the display surface side (that is, the common electrode 22 side) inside the microcapsule 80, thereby displaying the color of the white particles 82 (that is, white) on the display surface of the display unit 3. Can do. Conversely, when a voltage is applied between the pixel electrode 21 and the common electrode 22 so that the potential of the pixel electrode 21 becomes relatively high, the negatively charged white particles 82 are generated by the Coulomb force. While attracted to the electrode 21 side, the positively charged black particles 83 are attracted to the common electrode 22 side by Coulomb force. As a result, the black particles 83 gather on the display surface side of the microcapsule 80, whereby the color of the black particles 83 (that is, black) can be displayed on the display surface of the display unit 3.

  Hereinafter, a potential difference (that is, a voltage) generated between the pixel electrode 21 and the common electrode 22 when the potential of the pixel electrode 21 is higher than the potential of the common electrode 22 is appropriately referred to as a “positive voltage”. A potential difference generated between the pixel electrode 21 and the common electrode 22 when the potential of the common electrode 22 is higher than the potential of the pixel electrode 21 is appropriately referred to as a “negative voltage”.

  That is, by applying a positive voltage to the pixel 20, black can be displayed on the pixel 20, and by applying a negative voltage to the pixel 20, white can be displayed on the pixel 20. it can.

  Further, depending on the distribution state of the white particles 82 and the black particles 83 between the pixel electrode 21 and the common electrode 22, it is possible to display gray such as light gray, gray, dark gray and the like, which are intermediate gradations of white and black. is there. For example, by applying a voltage between the pixel electrode 21 and the common electrode 22 so that the potential of the common electrode 22 is relatively high (that is, by applying a negative voltage), After collecting the white particles 82 on the display surface side and the black particles 83 on the pixel electrode 21 side, the pixels are relatively placed between the pixel electrode 21 and the common electrode 22 for a predetermined period according to the halftone to be displayed. By applying a voltage so as to increase the potential of the electrode 21 (that is, by applying a positive voltage), the black particles 83 are moved by a predetermined amount to the display surface side of the microcapsule 80 and the pixel electrode 21 is moved. The white particles 82 are moved to the side by a predetermined amount. As a result, gray, which is a halftone between white and black, can be displayed on the display surface of the display unit 3.

  It should be noted that color display such as red, green, and blue can be performed by replacing the pigment used for the white particles 82 and the black particles 83 with pigments such as red, green, and blue. In addition to or instead of this, color display may be performed by applying a color filter.

  Next, each embodiment according to the electrophoretic display device described above will be described with reference to the following drawings in addition to FIGS.

<First Embodiment>
First, the first embodiment will be described with reference to FIGS.

  FIG. 5 is a schematic diagram illustrating the display unit of the electrophoretic display device in a state where an example of an image including a halftone is displayed.

  In the first embodiment, as shown in FIG. 5, the display unit displays halftone display areas Gd and Gl that respectively display relatively dark gray and relatively light gray as halftones, and white display that displays white. The case where it divides | segments into the 4 area | region which consists of the area | region W and the black display area B which displays black is taken as an example. Further, in FIG. 5, the pixel PX (1, 1) included in the halftone display area Gd and the same scanning line 40 as the pixel PX (1, 1) are electrically connected and included in the white display area W. Pixel PX (1,2), pixel PX (2,2) included in the halftone display area Gl, and black display that is electrically connected to the same scanning line 40 as the pixel PX (2,2). With reference to the pixel PX (2, 1) included in the region B, an example of the display operation will be described with reference to FIG. Note that the pixel PX (1,1) included in the halftone display area Gd and the pixel PX (2,1) included in the black display area B are electrically connected to the same data line 50 to display the halftone display. It is assumed that the pixel PX (2, 2) included in the region Gl and the pixel PX (1, 2) included in the white display region W are electrically connected to the same data line 50.

  FIG. 6 is a conceptual diagram illustrating one operation of the electrophoretic display device according to the present embodiment, and FIG. 7 is a conceptual diagram illustrating another operation of the electrophoretic display device according to the present embodiment. These are flowcharts which show the outline | summary of operation | movement of the electrophoretic display apparatus which concerns on this embodiment.

  Hereinafter, a state in which the pixel 20 displays white will be referred to as a first display state, and a state in which the pixel 20 displays black will be described as a second display state. In FIG. 6, when displaying an image including a halftone as shown in FIG. 5, for example, first, all white display for displaying white on all the pixels 20 in the display unit 3 is performed, and the first display state is set.

  At this time, in FIG. 2, in each pixel 20, a data signal is supplied to the memory circuit 25 from the data line 50 and held, and the pixel electrode 21 is electrically connected to the first or second control line 95 or 94 by the switch circuit 110. Connected to. The potential control unit 210 applies a negative voltage between the pixel electrode 21 and the common electrode 22 of all the pixels 20 in the display unit 3 so that the potential of the common electrode 22 becomes relatively high (that is, a negative voltage is applied). As described above, the potential of each of the first and second control lines 95 and 94 and the common potential Vcom are controlled.

  Subsequently, the following black writing (sometimes referred to as “normal black driving”, which is described as “normal black” in the drawing) is performed. In FIG. 8, prior to the normal black drive, the data signal is supplied from the data line 50 to the memory circuit 25 and held in the pixels 20 included in the halftone display areas Gd and Gl (Step S101; Hereinafter, this may be referred to as “data writing”). Thereby, in the pixels 20 included in the halftone display areas Gd and Gl, the pixel electrode 21 is electrically connected to the first control line 95 by the switch circuit 110, respectively.

  After that, the potential control unit 210 sets the common potential Vcom as a ground potential (GND) as an example of the third potential v3 so that a positive voltage is applied between the pixel electrode 21 and the common electrode 22 (step) S201), the potential of the first control line 95 is set to a second potential v2 higher than the first potential v1 (for example, GND) (step S202), and the potential of the second control line 94 is set to the first potential v1 (GND). (Step S203). In step S202, a voltage based on the potential difference between the first potential v1 (GND) and the second potential v2 is applied to the first control line 95.

  Thus, in the pixels 20 included in the halftone display areas Gd and Gl, the black particles 83 are moved to the common electrode 22 side (that is, by applying a positive voltage between the pixel electrode 21 and the common electrode 22 (that is, The white particles 82 are moved to the pixel electrode 21 side by a predetermined amount. At this time, in each of the pixels 20 included in the halftone display areas Gd and Gl, the gray is darker than the gray to be displayed (that is, the gray closer to the black than the gray to be displayed in FIG. When the density of black is 100%, a positive voltage is applied between the pixel electrode 21 and the common electrode 22 for a predetermined time so that a gray having a higher density than the gray density to be displayed is displayed. Applied. In other words, for a predetermined time during which the positive voltage is applied, a gray color darker than the gray to be displayed by the pixel 20 is displayed from the time when the positive voltage is started to be applied to the pixel 20 displaying the white color. It is set as the time until a possible time.

  FIG. 6 shows the colors displayed on the pixels 20 included in the halftone display areas Gd and Gl by the normal black drive and the inverted white drive described below (referred to as “inverted white” in the figure). The change of the density | concentration of is conceptually shown.

  That is, as shown in FIG. 6, in the normal black drive (steps S201 to S203), the gray level to be displayed on each of the pixels 20 included in the halftone display areas Gd and Gl (that is, the target density) is determined. A positive voltage is applied for a predetermined time so that a high gray level is displayed. In other words, a drive voltage pulse having durations Ta1 and Ta2 (see FIG. 9 described later) set in advance corresponding to a halftone closer to black than the halftone to be displayed on the pixel 20 to display the halftone. Pa1 and Pa2 (see FIG. 9 described later) are applied.

  More details will be described later with reference to FIG. 9, but in this embodiment, the pixels 20 included in the halftone display areas Gd and Gl are driven by at least one of two types of drive voltage pulses Pa1 and Pa2, respectively. Voltage pulses Pa1 and Pa2 are applied. The duration Ta1 of the drive voltage pulse Pa1 is twice the duration Ta2 of the drive voltage pulse Pa2. As a result, a potential difference is generated between the pixel electrode 21 and the common electrode 22 in accordance with the total duration obtained by adding the durations of the drive voltage pulses Pa1 or Pa2 applied to the pixel 20, and a positive voltage is applied. Is done. As a result, in each of the halftone display areas Gd and Gl, it is possible to display grays having different densities, that is, different gradations.

  In FIG. 6, after the normal black drive is performed, the inverted white drive is performed. The potential controller 210 is configured so that a negative voltage whose polarity is reversed from that of the voltage applied during the normal black drive is applied to the pixels 20 included in the halftone display areas Gd and Gl. The common potential Vcom is set to a fourth potential v4 higher than the third potential v3 (GND) (step S301), and the potential of the first control line 95 is set to the first potential v1 (GND) (step S302). The potential of the second control line 94 is switched to the second potential v2 (step S303). In step S301, a voltage based on the potential difference between the third potential v3 (GND) and the fourth potential v4 is applied to the common potential line 93. In step S303, the first potential v1 is applied to the second control line 95. A voltage based on the potential difference between (GND) and the second potential v2 is applied.

  Thereby, a negative voltage is applied to the pixels 20 included in the halftone display areas Gd and Gl for a predetermined time, respectively, and the black particles 83 are moved to the pixel electrode 21 side and the white particles 82 are moved to the common electrode 22 side ( That is, it is moved to the display surface side. As a result, the gray to be displayed (that is, the gray of the target density) is displayed in the pixel 20 that is to display gray.

  That is, as shown in FIG. 6, according to the present embodiment, after performing normal black driving (step S201 to step S203) on the pixel 20 to display gray, inverted white driving (step S301 to step S303). To display the gray to be displayed (that is, the gray of the target density). In the inverted white driving (steps S301 to S303), a negative voltage is applied to the pixel 20 that should display gray for a predetermined time. In other words, a negative voltage having a preset duration Tc1 (see FIG. 9 to be described later) is applied to the pixel 20 that should display halftone.

  FIG. 7 is a diagram having the same purpose as FIG. 6 and 8, an example in which an image including a halftone is displayed on the display unit 3 after all white display is performed, but as shown in FIG. 7, after all black display is performed (that is, as shown in FIG. 7). After displaying black on all the pixels 20), an image including a halftone may be displayed on the display unit 3.

  That is, in FIG. 7, after all black display is performed, white writing (hereinafter also referred to as “normal white driving”, which will be described as “normal white driving” in the drawing) and inverted black driving ( (Shown as “reversed black” in the figure) in this order. In normal white driving, the pixel electrode 21 and the common electrode 22 are displayed for a predetermined period of time so that a gray density lower than the gray density to be displayed (that is, the target density) is displayed on the pixel 20 that should display gray. A negative voltage is applied between the two. In the inverted black drive that is normally performed after performing the white drive, a positive voltage is applied between the pixel electrode 21 and the common electrode 22 of the pixel 20 on which the gray density lower than the gray density to be displayed is displayed for a predetermined time. By applying only this, gray to be displayed on the pixel 20 (that is, gray of a target density) is displayed.

  An example of the operation described with reference to FIGS. 6 and 8 will be described in detail with reference to FIG. FIG. 9 is a timing chart for explaining an operation example of the electrophoretic display device of the first embodiment.

  9 shows the data line 50 (data line Xd1 in FIG. 9) corresponding to the pixel PX (1, 1) included in the halftone display area Gd and the pixel PX (2, 1) included in the black display area B. ), The data line 50 (data line Xd2 in FIG. 9) corresponding to the pixel PX (2, 2) included in the halftone display area Gl and the pixel PX (1, 2) included in the white display area W, the halftone The scanning line 40 (scanning line Yl1 in FIG. 9) corresponding to the pixel PX (1,1) included in the display region Gd and the pixel PX (1,2) included in the white display region W, and the halftone display region Gl. The variation of the potential of the scanning line 40 (scanning line Yl2 in FIG. 9) and the common electrode Vcom corresponding to the pixel PX (2, 2) included and the pixel PX (2, 1) included in the black display region B is shown. ing. In addition, FIG. 9 also shows fluctuations in the potentials of the first and second control lines 95 and 94.

  First, after all white display is performed on the display unit 3, in the period from time t0 to time t1, scanning signals are supplied to the scanning lines Yl1 and Yl2 in this order in FIG. It becomes a level and is selected sequentially. During the period when the scanning line Yl1 is at the high level, the data line Xd1 is at the high level based on the data signal, and the data line Xd2 is at the low level based on the data signal. Accordingly, in the pixel PX (1, 1) included in the halftone display area Gd and the pixel PX (1, 2) included in the white display area W, the pixel switching transistor 24 is turned on, and the pixel PX (1, 1 ), A high level data signal is supplied to and held in the memory circuit 25 via the data line Xd1, and a low level data signal is supplied to the memory circuit 25 via the data line Xd2 in the pixel PX (1,2). And retained. Therefore, in the pixel PX (1, 1), the pixel electrode 21 is electrically connected to the first control line 95 by the switch circuit 110, and in the pixel PX (1, 2), the pixel electrode 21 is connected to the first control line 95 by the switch circuit 110. The second control line 94 is electrically connected.

  Subsequently, during a period in which the scanning line Yl2 is at a high level, the data line Xd1 is at a high level based on the data signal, and the data line Xd2 is at a low level based on the data signal. Therefore, a high level data signal is supplied to and held in the memory circuit 25 via the data line Xd1 in the pixel PX (2, 1) included in the black display area B, and the pixel PX ( 2, 2), a low level data signal is supplied to and held in the memory circuit 25 via the data line Xd2. Therefore, in the pixel PX (2, 1), the pixel electrode 21 is electrically connected to the first control line 95 by the switch circuit 110, and in the pixel PX (2, 2), the pixel electrode 21 is connected to the first control line 95 by the switch circuit 110. The second control line 94 is electrically connected.

That is, data writing (step S101) is performed during a period from time t0 to time t1, and then normal black driving is performed during a period from time t2 to time t3. The potential control unit 210 sets the common potential Vcom to the third potential v3 (GND) (step S201), sets the potential of the first control line 95 to the second potential v2 (step S202), and sets the second control line 94. Is switched to the first potential v1 (GND) (step S203).
At this time, a drive voltage pulse Pa1 having a preset duration Ta1 corresponding to a halftone closer to black than the halftone to be displayed is applied to the pixel PX (1, 1) where halftone is to be displayed. The Accordingly, in the pixel PX (1, 1), the gray is darker than the gray to be displayed (that is, the gray closer to the black than the gray to be displayed in FIG. In this case, a positive voltage is applied between the pixel electrode 21 and the common electrode 22 for a predetermined time so that a gray color higher than the gray density to be displayed is displayed.

  The drive voltage pulse Pa1 is also applied to the pixel PX (2, 1) that should display black, and normal black drive is performed.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the other pixel PX (2, 2) that should display halftone. The first display state is maintained.

  In FIG. 9, after the normal black drive is performed, data writing is performed again in the period from time t4 to t5 (step S101). At this time, each of the scanning line Yl1 and the scanning line Yl2 is sequentially selected because the potential becomes a high level.

  During the period when the scanning line Yl1 is at the high level, the data line Xd1 and the data line Xd2 are at the low level based on the data signal, respectively. Therefore, in the pixel PX (1,1) included in the halftone display area Gd and the pixel PX (1,2) included in the white display area W, the low level is respectively obtained via the data line Xd1 and the data line Xd2. A data signal is supplied to the memory circuit 25 and held. Therefore, the pixel electrode 21 is electrically connected to the second control line 94 by the switch circuit 110 in each of the pixel PX (1,1) and the pixel PX (1,2).

  Subsequently, during a period in which the scanning line Yl2 is at a high level, the data line Xd1 and the data line Xd2 are each at a high level based on the data signal. Accordingly, the pixel PX (2,1) included in the black display area B and the pixel PX (2,2) included in the halftone display area Gl are respectively high-level data via the data line Xd1 and the data line Xd2. The signal is supplied to the memory circuit 25 and held. Therefore, in the pixel PX (2, 1) and the pixel PX (2, 2), the pixel electrode 21 is electrically connected to the first control line 95 by the switch circuit 110, respectively.

  Subsequently, normal black driving is performed during a period from time t6 to time t7. The potential control unit 210 sets the common potential Vcom to the third potential v3 (GND) (step S201), sets the potential of the first control line 95 to the second potential v2 (step S202), and sets the second control line 94. Is switched to the first potential v1 (GND) (step S203). At this time, a driving voltage pulse Pa2 having a preset duration Ta2 corresponding to a halftone closer to black than the halftone to be displayed is applied to the pixel PX (2, 2) where halftone is to be displayed. The Therefore, in the pixel PX (2, 2), a positive voltage is applied between the pixel electrode 21 and the common electrode 22 for a predetermined time so that a darker gray than the gray to be displayed is displayed.

  Here, a positive voltage is applied to the pixel PX (1, 1) between the pixel electrode 21 and the common electrode 22 in accordance with the total duration Ta1 of the applied one drive voltage pulse Pa1. A positive voltage is applied between PX (2, 2) between the pixel electrode 21 and the common electrode 22 in accordance with the total duration Ta2 of the applied drive voltage pulse Pa2. That is, the pixel PX (1,1) is displayed in a darker gray than the pixel PX (2,2), in other words, the pixel PX (2,2) is relatively pixel PX (1,1). The drive voltage pulse Pa1 and the drive voltage pulse Pa2 are applied so that a lighter gray is displayed. As a result, in each of the halftone display areas Gd and Gl, it is possible to display grays having different densities, that is, different gradations.

  The drive voltage pulse Pa2 is also applied to the pixel PX (2, 1) that should display black, and normal black drive is performed.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the one pixel PX (1, 1) that should display halftone.

  Subsequently, in FIG. 9, data writing is performed again during the period from time t8 to t9 (step S101). At this time, each of the scanning line Yl1 and the scanning line Yl2 is sequentially selected because the potential becomes a high level. During the period when the scanning line Yl1 is at the high level, the data line Xd1 is at the high level based on the data signal, and the data line Xd2 is at the low level based on the data signal.

  Therefore, in the pixel PX (1,1) included in the halftone display area Gd and the pixel PX (1,2) included in the white display area W, the pixel PX (1,1) is connected to the high level via the data line Xd1. A level data signal is supplied to and held in the memory circuit 25, and a low level data signal is supplied to and held in the memory circuit 25 via the data line Xd2 in the pixel PX (1, 2). Therefore, in the pixel PX (1, 1), the pixel electrode 21 is electrically connected to the first control line 95 by the switch circuit 110, and in the pixel PX (1, 2), the pixel electrode 21 is connected to the first control line 95 by the switch circuit 110. The second control line 94 is electrically connected.

  Subsequently, during a period in which the scanning line Yl2 is at a high level, the data line Xd1 is at a low level based on the data signal, and the data line Xd2 is at a high level based on the data signal. Accordingly, a low level data signal is supplied to and held in the memory circuit 25 via the data line Xd1 in the pixel PX (2, 1) included in the black display area B, and the pixel PX ( 2, 2), a high-level data signal is supplied to and held in the memory circuit 25 via the data line Xd2. Therefore, in the pixel PX (2, 1), the pixel electrode 21 is electrically connected to the second control line 94 by the switch circuit 110, and in the pixel PX (2, 2), the pixel electrode 21 is connected to the second control line 94 by the switch circuit 110. 1 control line 95 is electrically connected.

  Thereafter, inversion white driving is performed during a period from time t10 to time t11. The potential control unit 210 sets the common potential Vcom to the fourth potential v4 for the duration Tc1 from the time t10 to the time t11 (step S301), and sets the potential of the first control line 95 to the first potential v1 (GND). (Step S302), the potential of the second control line 94 is switched to the second potential v2 (Step S303). It is assumed that the second potential v2 and the fourth potential v4 are supplied by the potential control unit 210 so as to be the same potential.

  A negative voltage is applied to the pixels PX (1,1) and PX (2,2) included in the halftone display areas Gd and Gl for a predetermined time, respectively, and the black particles 83 are moved to the pixel electrode 21 side. The white particles 82 are moved to the common electrode 22 side (that is, the display surface side). As a result, the gray to be displayed (that is, the gray of the target density) is displayed in the pixel 20 that is to display gray.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the pixel PX (2, 1) that should display black.

  Here, with reference to FIG. 10 and FIG. 11, description will be given focusing on the operations in the normal black drive and the inverted white drive in the pixel 20 that should display gray. FIG. 10 is an explanatory diagram schematically showing an operation in normal black driving in a pixel to display gray, and FIG. 11 is an explanatory diagram schematically showing an operation in inverted white driving in a pixel to display gray. FIG.

  Note that the circuit configurations of the three types of pixels 20L, 20M, and 20S shown in FIGS. 10 and 11 are shown with some parts omitted while simplifying the configuration described with reference to FIG. is there. 10 and 11, the three types of pixels 20L, 20M, and 20S are respectively operated by the operation as described above (see FIG. 9), and the pixel electrodes 21 are respectively connected by the switch circuits 110L, 110M, and 110S. In this state, the first control line 95 is electrically connected.

  In FIG. 10, as already described with reference to FIG. 9, in the normal black drive, the common potential Vcom is set to the third potential v <b> 3 (GND) by the potential control unit 210, and the potential of the first control line 95 is the first potential. The potential of the second control line 94 is controlled as the first potential v1 (GND). Here, in each of the three types of pixels 20L, 20M, and 20S, the first control line 95 is caused by the manufacturing variations of the transistors Sw1L, Sw1M, and Sw1S constituting the switch circuits 110L, 110L, and 110M, respectively. And the value of the electrical resistance between the electrophoretic element 23 may vary. In FIG. 10, the electrical resistance of the transistor Sw1L is relatively small, the electrical resistance of the transistor Sw1M is relatively medium, and the electrical resistance of the transistor Sw1S is relatively large and varies. Yes.

  As a result, in the electrophoretic element 23 to which the potential v2 is supplied via the transistor Sw1L, a relatively large voltage is applied to the microcapsule 80L, and in the electrophoretic element 23 to which the potential v2 is supplied via the transistor Sw1M. In the electrophoretic element 23 to which a relatively medium voltage is applied to the microcapsule 80M and the potential v2 is supplied via the transistor Sw1S, a relatively small voltage is applied to the microcapsule 80S. Therefore, the migration amount of black or white particles in the microcapsule 80L is increased, and a relatively dark gray display (Cg3) is made. On the other hand, the migration amount of black or white particles in the microcapsule 80S is reduced, A light gray display (Cg1) is made. Similarly, for the microcapsule 80M, depending on the migration amount of black or white particles, a gray display (Cg2) having a relatively medium density (medium density compared to the microcapsules 80L and 80S). ) Is made. Therefore, in this state, there is a possibility that noise is visually noticeably generated in the gray display areas Gd and Gl.

  Subsequently, in the inverted white driving in FIG. 11, as already described with reference to FIG. 9, the potential controller 210 sets the common potential Vcom to the fourth potential v4 and sets the potential of the first control line 95 to be the same. The first potential v1 (GND) is set, and the potential of the second control line 94 is switched to the second potential v2. At this time, the polarity of the voltage applied to each of the microcapsules 80L, 80M, and 80S is inverted in each of the three types of pixels 20L, 20M, and 20S, compared to the case of the normal black drive shown in FIG. Different. That is, the magnitude relationship between the voltages applied to the microcapsules 80L, 80M, and 80S is the same as in FIG.

  Thereby, the black or white particles in the microcapsule 80L move relatively large, while the black or white particles in the microcapsule 80S move relatively small. Accordingly, the amount of movement of black or white particles in the reversed white driving increases the variation with respect to the total movement amount, and does not return to the initial state (first display state), but displays the same darkness (Cg1 ~ Cg3) can be performed.

  Therefore, in the present embodiment, when displaying halftone as described above, the inversion white driving is performed after the normal black driving, which is caused by the manufacturing variation of the pixel circuit provided in each of the plurality of pixels 20. Noise on the display can be reduced or eliminated (that is, it is possible to reduce the display of different halftones between pixels that should display the same halftone). That is, according to the electrophoretic display device of the present invention, for example, the pixel electrode 21 and the common pixel electrode 21 are common to the pixel 20 that should display the halftone, as compared with the case where the target halftone is displayed only by the normal black drive. Since the time for applying a voltage between the electrodes 22 can be lengthened, noise that tends to be more prominently generated when the drive voltage is applied (that is, noise when displaying a halftone) is effectively reduced. It can be reduced or eliminated. As a result, high-quality display can be performed.

  In FIG. 9, the potential control unit 210 is applied to the first control line 95, the second control line 94, and the common potential line 93 during the inversion white driving (period from time t <b> 10 to time t <b> 11). The inversion duration Tc1 for maintaining the inverted state of each voltage is preferably shorter than the total duration Ta1 or Ta2 of the drive voltage pulse Pa1 or Pa2. Therefore, for example, the halftone can be displayed more quickly than the case where the inversion duration Tc1 is longer than the total duration Ta1 or Ta2 of the drive voltage pulse Pa1 or Pa2 (that is, the halftone to be displayed is displayed). Can reduce the time needed to do that). Furthermore, power consumption required to apply voltages to the first and second control lines 95 and 94 and the common potential line 93 can be suppressed.

  The potential controller 210 may make the inversion duration Tc1 as described above longer than the total duration Ta1 or Ta2 of the drive voltage pulse Pa1 or Pa2. In this case, for example, when the negative polarity voltage is applied to the space between the pixel electrode 21 and the common electrode 22, the electrophoretic particles contained in the electrophoretic layer are less likely to move. However, by reversing the voltages applied to the first and second control lines 95 and 94 and the common potential line 93, the halftone to be displayed can be reliably displayed. In this case, the inversion duration may be set based on, for example, characteristics of the electrophoretic particles included in the electrophoretic layer (for example, ease of movement of the electrophoretic particles).

  Furthermore, in FIG. 9, after all the two kinds of drive voltage pulses Pa1 and Pa2 are applied, the potential of the first control line 95, the potential of the second control line 94, and the common potential Vcom are inverted. Therefore, for example, each time one driving voltage pulse Pa1 or Pa2 of at least one driving voltage pulse Pa1 and Pa2 is applied, the potential of each of the first and second control lines 95 and 94 and the common potential Vcom are set to Compared to the case where each is inverted (see the second embodiment described later), halftones can be displayed quickly (that is, the time required to display the halftones to be displayed can be shortened). it can). Furthermore, power consumption required to apply voltages to the first and second control lines 95 and 94 and the common potential line 93 can be suppressed.

  Further, according to FIG. 9, for the pixel 20 in which the first or second display state is selected, the potential of the first control line 95, the potential of the second control line 94, and the common potential Vcom Therefore, the polarity of the voltage between the pixel electrode 21 and the common electrode 22 is not reversed. Accordingly, each of the pixels 20 in which the first and second display states are selected, that is, each of the pixels 20 included in the region W in which white is to be displayed and the region B in which black is to be displayed in FIG. Alternatively, the second display state can be set. That is, in this case, in the region B where black is to be displayed, when the pixel 20 in the first display state is set to the second display state, only the driving voltage pulses Pa1 and Pa2 are applied to the pixel 20. Thereafter, the voltage between the pixel electrode 21 and the common electrode 22 is not inverted. On the other hand, in the region W where white is to be displayed, this state is maintained for the pixels 20 in the first display state.

  Therefore, the pixel 20 that should be in the second display state can be prevented from becoming a display state closer to the first display state than the second display state (for example, black close to white). On the other hand, the pixel 20 that should be in the first display state can be similarly prevented from becoming a display state (for example, white close to black) closer to the second display state than the first display state.

  Therefore, according to the present embodiment as described above, it is possible to reduce noise when displaying a halftone, and to perform high-quality display.

Second Embodiment
Next, a second embodiment will be described with reference to FIG. FIG. 12 is a timing chart for explaining an operation example of the electrophoretic display device of the second embodiment.

  The second embodiment is partially different from the first embodiment in the operation example of the electrophoretic display device. Hereinafter, a part different from the first embodiment will be described in detail, and other similar parts may be omitted or simplified by referring to the already described drawings.

  In the second embodiment, as in the first embodiment, the display unit is divided into four areas including halftone display areas Gd and G1, a white display area W, and a black display area B in FIG. 5 as an example. . FIG. 12 shows the potential fluctuations of the data line Xd1, the data line Xd2, the scanning line Yl1, the scanning line Yl2, and the common electrode Vcom, respectively, and the potential fluctuations of the first and second control lines 95 and 94, respectively. Is also shown.

  First, after all white display is performed on the display unit 3, the data line Xd1 becomes high level based on the data signal during the period in which the scanning line Yl1 becomes high level during the data writing period from time t0 to time t1. The data line Xd2 becomes low level based on the data signal, and during the period when the scanning line Yl2 becomes high level, the data line Xd1 becomes high level based on the data signal, and the data line Xd2 becomes low level based on the data signal. Become.

  Accordingly, the pixel electrode 21 is electrically connected to the first control line 95 in the pixel PX (1, 1), and the pixel electrode 21 is electrically connected to the second control line 94 in the pixel PX (1, 2). Is done. Thereafter, the pixel electrode 21 is electrically connected to the first control line 95 in the pixel PX (2, 1), and the pixel electrode 21 is electrically connected to the second control line 94 in the pixel PX (2, 2). Is done.

  Subsequently, normal black driving is performed during a period from time t2 to time t3. The pixel electrode 21 and the common electrode 22 are applied so that a drive voltage pulse Pa1 having a duration Ta1 is applied to the pixel PX (1,1) to display halftone, and a gray color darker than the gray color to be displayed is displayed. A positive voltage is applied for a predetermined time. The drive voltage pulse Pa1 is also applied to the pixel PX (2, 1) that should display black, and normal black drive is performed. On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the other pixel PX (2, 2) that should display halftone. The first display state is maintained.

  Subsequently, inversion white driving is performed during a period from time t4 to time t5. The potential controller 210 changes the common potential Vcom from the third potential v3 (GND) to the fourth potential v4 for the duration Tc2 of the period from time t4 to time t5, and sets the potential of the first control line 95 to the second potential. From the first potential v2 to the first potential v1 (GND), and the potential of the second control line 94 is switched from the first potential v1 (GND) to the second potential v2. A negative voltage is applied to the pixel PX (1,1) to display halftone and the pixel PX (2,1) to display black for a predetermined time, and the black particles 83 are moved to the pixel electrode 21 side. At the same time, the white particles 82 are moved to the common electrode 22 side (that is, the display surface side). As a result, the gray to be displayed (that is, the gray of the target density) is displayed in the pixel 20 that is to display gray.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the other pixel PX (2, 2) that should display halftone.

  In FIG. 12, data is written again during a period from time t6 to t7. The data line Xd1 and the data line Xd2 are each at a low level based on the data signal while the scanning line Yl1 is at a high level, and the data line Xd1 and the data line Xd2 are at a data signal during a period when the scanning line Yl2 is at a high level. Each will be at a high level. Therefore, in the pixel PX (1, 1) and the pixel PX (1, 2), the pixel electrode 21 is electrically connected to the second control line 94, and the pixel PX (2, 1) and the pixel PX (2, 2 ), The pixel electrode 21 is electrically connected to the first control line 95, respectively.

  Subsequently, normal black driving is performed during a period from time t8 to time t9. At this time, the drive voltage pulse Pa2 having the duration Ta2 is applied to the pixel PX (2, 2) that should display the halftone, and the pixel electrode 21 and the pixel electrode 21 are displayed so that a gray that is darker than the gray that should be displayed is displayed. A positive voltage is applied to the common electrode 22 for a predetermined time. The drive voltage pulse Pa2 is also applied to the pixel PX (2, 1) that should display black, and normal black drive is performed.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the one pixel PX (1, 1) that should display halftone.

  Subsequently, inversion white driving is performed during a period from time t10 to time t11. The potential control unit 210 changes the common potential Vcom from the third potential v3 (GND) to the fourth potential v4 for the duration Tc3 from the time t10 to the time t11, and sets the potential of the first control line 95 to the second potential. From the first potential v2 to the first potential v1 (GND), and the potential of the second control line 94 is switched from the first potential v1 (GND) to the second potential v2.

  A negative voltage is applied to the pixel PX (2, 2) to display halftone and the pixel PX (2, 1) to display black for a predetermined time, and the black particles 83 are moved to the pixel electrode 21 side. At the same time, the white particles 82 are moved to the common electrode 22 side (that is, the display surface side). As a result, the gray to be displayed (that is, the gray of the target density) is displayed in the pixel 20 that is to display gray.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the one pixel PX (1, 1) that should display halftone.

  Therefore, in the second embodiment as described above, one drive voltage pulse Pa1 or Pa2 out of at least one drive voltage pulse Pa1 and Pa2 is compared with the operation example of the first embodiment (see FIG. 9). The difference is that the potential of each of the first and second control lines 95 and 94 and the common potential Vcom are inverted each time the voltage is applied (that is, every time black driving is performed). Therefore, according to the second embodiment, it is possible to obtain the same gain as in the first embodiment.

<Third Embodiment>
Next, a third embodiment will be described with reference to FIGS. 13 and 14.

  13 and 14 are timing charts for explaining an operation example of the electrophoretic display device of the third embodiment. FIG. 13 is a timing chart in a period from time t0 to time t7, and FIG. 14 is a timing chart in a period from time t8 to time t15 after time t7.

  The third embodiment is partially different from the first and second embodiments in the operation example of the electrophoretic display device. Hereinafter, a part different from the first and second embodiments will be described in detail, and other similar parts may be omitted or simplified by referring to the already described drawings.

  Also in the third embodiment, as in the first and second embodiments, in FIG. 5, the display unit is divided into four regions including halftone display regions Gd and Gl, white display region W, and black display region B. Take an example. FIGS. 13 and 14 show the potential fluctuations of the data line Xd1, the data line Xd2, the scanning line Yl1, the scanning line Yl2, and the common electrode Vcom, respectively, and the potentials of the first and second control lines 95 and 94, respectively. The fluctuations are also shown.

  In FIG. 13, in the data writing period from time t0 to time t1, the data line Xd1 becomes high level based on the data signal and the data line Xd2 becomes low level based on the data signal during the period when the scanning line Yl1 becomes high level. During the period when the scanning line Yl2 is at the high level, the data line Xd1 is at the high level based on the data signal, and the data line Xd2 is at the low level based on the data signal. Therefore, the pixel electrode 21 is electrically connected to the first control line 95 in the pixel PX (1, 1), and the pixel electrode 21 is electrically connected to the second control line 94 in the pixel PX (1, 2). Is done. In the pixel PX (2,1), the pixel electrode 21 is electrically connected to the first control line 95, and in the pixel PX (2,2), the pixel electrode 21 is electrically connected to the second control line 94. Is done.

  Subsequently, normal black driving is performed during a period from time t2 to time t3, and the pixel PX (1,1) and the pixel PX (2,1) are each set to a state in which black is displayed, that is, the second display state. At this time, the potential controller 210 sets the common potential Vcom to the third potential v3 (GND), sets the potential of the first control line 95 to the second potential v2, and sets the potential of the second control line 94 to the first potential. Is switched to the potential v1 (GND). At this time, the one pixel PX (1,1) that should display halftone and the pixel PX (2,1) that should display black have a driving duration Ta0 set in advance to display black. A voltage pulse Pa0 is applied. Therefore, in the pixel PX (1, 1) and the pixel PX (2, 1), a positive voltage is applied between the pixel electrode 21 and the common electrode 22 for a predetermined time so that black is displayed.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the other pixel PX (2, 2) that should display halftone, In the subsequent period from time t4 to time t5, normal white driving (see FIG. 7) is performed, and the pixel PX (1,2) and the pixel PX (2,2) are each set to a white display state, that is, a first display state. .

  Specifically, in the normal white driving during the period from time t4 to time t5, the potential control unit 210 sets the common potential Vcom to the fourth potential v4 and sets the potential of the first control line 95 to the second potential v2. The potential of the second control line 94 is switched to the first potential v1 (GND). At this time, the other pixel PX (2, 2) that should display halftone and the pixel PX (1, 2) that should display white have a driving time Tb0 that is set in advance to display white. A voltage pulse Pb0 is applied. Therefore, in the pixel PX (1,2) and the pixel PX (2,2), a negative voltage is applied between the pixel electrode 21 and the common electrode 22 for a predetermined time so that white is displayed.

  Subsequently, in FIG. 13, data writing is performed again during the period from time t6 to t7. The data line Xd1 and the data line Xd2 are each at a low level based on the data signal while the scanning line Yl1 is at a high level, and the data line Xd1 and the data line Xd2 are at a data signal during a period when the scanning line Yl2 is at a high level. Each will be at a high level. Therefore, in the pixel PX (1, 1) and the pixel PX (1, 2), the pixel electrode 21 is electrically connected to the second control line 94, and the pixel PX (2, 1) and the pixel PX (2, 2 ), The pixel electrode 21 is electrically connected to the first control line 95, respectively.

  Subsequently, in FIG. 14, normal black driving is performed during a period from time t8 to time t9. At this time, the drive voltage pulse Pa3 having the duration Ta3 is applied to the pixel PX (2, 2) that should display halftone, and the pixel electrode 21 and the pixel electrode 21 are displayed so that a gray that is darker than the gray that should be displayed is displayed. A positive voltage is applied to the common electrode 22 for a predetermined time. The drive voltage pulse Pa3 is also applied to the pixel PX (2, 1) that should display black, and normal black drive is performed.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the one pixel PX (1, 1) that should display halftone.

  Subsequently, inversion white driving is performed during a period from time t10 to time t11. The potential control unit 210 changes the common potential Vcom from the third potential v3 (GND) to the fourth potential v4 for the duration Tc4 from the time t10 to the time t11, and sets the potential of the first control line 95 to the second potential. From the first potential v2 to the first potential v1 (GND), and the potential of the second control line 94 is switched from the first potential v1 (GND) to the second potential v2.

  A negative voltage is applied to the pixel PX (2, 2) to display halftone and the pixel PX (2, 1) to display black for a predetermined time, and the black particles 83 are moved to the pixel electrode 21 side. At the same time, the white particles 82 are moved to the common electrode 22 side (that is, the display surface side). As a result, the gray to be displayed (that is, the gray of the target density) is displayed in the pixel 20 that is to display gray.

  On the other hand, there is no potential difference between the pixel electrode 21 and the common electrode 22 in the pixel PX (1, 2) that should display white and the one pixel PX (1, 1) that should display halftone.

  Subsequently, normal white driving is performed during a period from time t12 to time t13. The potential control unit 210 sets the common potential Vcom to the fourth potential v4 and sets the potential of the first control line 95 to the second potential v2 for the duration Tb3 from the time t12 to the time t13, and performs the second control. The potential of the line 94 is switched to the first potential v1 (GND). At this time, a drive voltage pulse Pb3 having a preset duration Tb3 corresponding to a halftone that is closer to white than the halftone to be displayed is applied to one pixel PX (1,1) that is to display the halftone. Applied. Accordingly, as already described with reference to FIG. 7, the pixel PX (1,1) has a lighter gray than the gray to be displayed (that is, a gray closer to white than the gray to be displayed in FIG. When the density is 0% and the density of black is 100%, a negative polarity is displayed between the pixel electrode 21 and the common electrode 22 so that a gray color lower than the gray density to be displayed is displayed. A voltage is applied for a predetermined time. Further, the drive voltage pulse Pb3 is also applied to the pixel PX (1, 2) that should display white, and normal white drive is performed.

  Thereafter, inversion black driving is performed during a period from time t14 to time t15. The potential control unit 210 sets the common potential Vcom to the third potential v3 (GND) and sets the potential of the first control line 95 to the first potential v1 for the duration Tc5 from the time t14 to the time t15. The potential of the second control line 94 is switched to the second potential v2. A positive voltage is applied to the one pixel PX (1,1) to display halftone and the pixel PX (1,2) to display white for a predetermined time, and the black particles 83 are attached to the common electrode 22. The white particles 82 are moved to the pixel electrode 21 side while moving to the side (that is, the display surface side). As a result, the gray to be displayed (that is, the gray of the target density) is displayed in the pixel 20 that is to display gray.

  On the other hand, in each of the normal white drive and the inverted black drive, the pixel electrode 21 and the common electrode are respectively used in the pixel PX (2, 1) that should display black and the other pixel PX (2, 2) that should display halftone. No potential difference occurs with respect to 22.

  In the third embodiment, normal white drive and inverted black drive are performed in addition to normal black drive and inverted white drive, respectively. In normal white driving and inverted black driving, the pixel 20 in the second display state (that is, black) is set to the first display state (that is, white) rather than the halftone to be displayed by applying at least one driving voltage pulse Pb3. In the close state, it returns to the halftone to be displayed on the second display state side.

  In addition, by data writing, for example, the pixel electrode 21 for the first and second control lines 95 and 94 in one pixel PX (1,1) and the other pixel PX (2,2) that should display halftones, respectively. Therefore, the normal black drive (from time t8 to time t11) and the reverse white drive (from time t10 to time t11) and the normal white drive (from time t12 to time t13) are performed. Period) and inversion black drive (period from time t14 to time t15) can be performed without changing the electrical connection state of the pixel electrode 21 to the first and second control lines 95 and 94, respectively. Therefore, the supply of the data signal via the data line 50 can be simplified, and the halftone can be displayed more easily and with high quality.

<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. 15 is a perspective view illustrating a configuration of the electronic paper 400.

  As illustrated in FIG. 15, the electronic paper 400 includes the electrophoretic display device according to the above-described embodiment as a display unit 401. The electronic paper 400 has flexibility, and includes a main body 402 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 500.

  As shown in FIG. 16, an electronic notebook 500 is one in which a plurality of electronic papers 400 shown in FIG. 15 are bundled and sandwiched between covers 501. The cover 501 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 above-described electronic paper 400 and electronic notebook 500 include the electrophoretic display device according to the above-described embodiment, high-quality image display can be performed.

  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. The apparatus and the electronic apparatus provided with the electrophoretic display device are also included in the technical scope of the present invention.

  20 ... Pixel, 21 ... Pixel electrode, 22 ... Common electrode, 23 ... Electrophoretic element, 24 ... Pixel switching transistor, 25 ... Memory circuit, 40 ... Scan line, 50 ... Data line, 94 ... Second control line, 95: First control line, 110: Switch circuit, 210: Potential control unit

Claims (7)

An electrophoretic element provided corresponding to the intersection of the scanning line and the data line, and including a first electrode, a second electrode, and electrophoretic particles sandwiched between the first electrode and the second electrode; An electrophoretic display device including a plurality of pixels including a pixel switching element and a memory circuit,
A first control line; a second control line; a switch circuit provided in the pixel; and a potential controller.
The pixel switching element is provided between an input terminal of the memory circuit and the data line,
The switch circuit is provided between an output terminal of the memory circuit and the first electrode;
The connection state between the first control line and the first electrode and the connection state between the second control line and the first electrode are based on a data signal supplied from the data line. Controlled by
The potential controller is
The potential supplied to the first control line is between the first potential and the second potential,
The potential supplied to the second control line is between the first potential and the second potential,
The potential supplied to the second electrode is between a third potential and a fourth potential,
switching,
When the potential of the first electrode is higher than the potential of the second electrode, the potential difference generated between the first electrode and the second electrode is positive.
As the display state of the pixel,
The first display state is selected by applying one of a positive voltage and a negative voltage different from the positive voltage to the electrophoretic element,
A second display state is selected by applying, to the electrophoretic element, a voltage different from the one of the positive voltage and the negative voltage,
A halftone between the first display state and the second display state is selected according to a total duration of at least one drive voltage pulse applied to the electrophoretic element of the pixel in the first display state And
Inversion of voltages applied to the first control line, the second control line, and the second electrode in a state where the data signal supplied from the data line is held in the memory circuit. An electrophoretic display device.   The inversion duration for maintaining the state in which the voltages applied to the first control line, the second control line, and the second electrode are inverted is the total duration of the at least one drive voltage pulse. The electrophoretic display device according to claim 1, wherein the electrophoretic display device is shorter.   The inversion duration for maintaining the state in which the voltages applied to the first control line, the second control line, and the second electrode are inverted is the total duration of the at least one drive voltage pulse. The electrophoretic display device according to claim 1, wherein the electrophoretic display device is longer than the electrophoretic display device.   2. The voltage applied to the first control line, the second control line, and the second electrode is inverted after all of the at least one driving voltage pulse is applied. 4. The electrophoretic display device according to any one of items 1 to 3.   For pixels for which the first or second display state is selected, the first and second control lines, the second control line, and the first and second voltages based on the voltage applied to the second electrode. The electrophoretic display device according to claim 1, wherein the polarity of the voltage between the two electrodes is not reversed. Applying at least one second drive voltage pulse, which is the first drive voltage pulse as the first drive voltage pulse, and the first drive voltage pulse is inverted to the pixel in the second display state;
The voltage applied to the first control line, the second control line, and the second electrode is inverted after applying the first and second drive voltage pulses, respectively. The electrophoretic display device according to any one of 1 to 3.   An electronic apparatus comprising the electrophoretic display device according to claim 1.