JP4613514B2 - Image display device - Google Patents

Description

The present invention relates to images display device, in particular, to one housing images display device that can display images on both sides of.

  Conventionally, an electrophoretic display device that displays an image using an electrophoretic phenomenon is known. In this electrophoretic display device, one of the transparent display substrate and the back substrate disposed opposite thereto forms a sealed space with a predetermined gap through a surrounding gap spacer, and the sealed space is colored. A display portion filled with a liquid dispersion medium containing charged particles is formed. Then, by generating an electric field in the display unit, the charged particles in the liquid dispersion medium are moved to the display substrate side, and the color of the charged particles is displayed on the surface of the display substrate, or the charged particles are displayed on the rear substrate side. The desired image can be obtained by moving to the position where the color of the charged particles is not displayed.

Further, a double-sided display type electrophoretic display that forms one electrophoretic display device in which the back substrates of two electrophoretic display devices are joined together and can display images in opposite directions on the respective display substrates. An apparatus is known (for example, refer to Patent Document 1). In such a double-sided display type electrophoretic display device, various displays using a plurality of display substrates are possible, and images can be simultaneously displayed to a plurality of persons surrounding the casing.
JP 2003-186062 A

  However, in the above-described prior art, even though images can be displayed on both sides of one casing, the two casings are essentially provided with two electrophoretic display devices. In such a double-sided display type electrophoretic display device, it is difficult to reduce the manufacturing cost and the number of parts.

  Therefore, it is conceivable that in one electrophoretic display device, the back substrate is also used as a transparent display surface to reduce the number of components and the manufacturing cost and realize double-sided display. However, when an electric field is generated in the display unit with a configuration in which the rear substrate is a transparent display surface, the normal image shown in FIG. 17 is displayed on the display substrate, while the display on the rear substrate is as shown in FIG. There is a problem that an image to be displayed and its color are inverted. This is because the charged particles to display an image move in the direction of the display substrate due to the generation of an electric field in the display unit, and the color of the charged particles appears on the surface of the display substrate, while the image is displayed in the direction of the back substrate. This is because charged particles other than the charged particles to be moved move, and the charged particles other than the charged particles to display an image are displayed on the surface of the back substrate.

The present invention has been made to solve the above problem, an image can be displayed on both sides of one housing, and which aims to provide a manufacturing cost and number of parts is reduced and images display.

In order to achieve the above object, an image display device according to a first aspect of the present invention is provided with a first display portion having charged particles that move in accordance with the direction of an electric field, and facing the first display portion. Provided in common to the second display portion having charged particles that move in accordance with the direction of the electric field, the first display portion, and the second display portion, and the first display portion and the second display portion. A common substrate having a common electrode used in common for the two display portions, and a first substrate disposed opposite to the common substrate so as to enclose the charged particles of the first display portion between the common substrate and the common substrate. A first display substrate having one electrode, and a second electrode provided opposite to the common substrate so as to enclose charged particles of the second display portion between the first display substrate and the common substrate. a second display substrate to separately generate an electric field between the first display unit and the second display unit The image display medium control means supplies power to the common electrode and the first electrode or the second electrode, and the image display medium control means applies an electric field to the first display section. When generating the electric field, the second electrode is controlled to be electrically disconnected. When generating an electric field in the second display portion, the first electrode is controlled to be electrically disconnected. Features.

In the image display apparatus of the invention according to claim 2, in addition to the configuration of the invention according to claim 1, wherein the common electrode functions as a driving side electrode, the first electrode is grounded side with respect to the common electrode The second electrode functions as a ground-side electrode with respect to the common electrode, generates an electric field between the common electrode and the first electrode, and causes charged particles of the first display unit to The charged particles of the second display portion are moved by moving or generating an electric field between the common electrode and the second electrode.

In the image display apparatus of the invention according to claim 3, in addition to the configuration of the invention according to claim 1, wherein the common electrode functions as a ground side electrode, the first electrode functions as a driving-side electrode The second electrode functions as a drive-side electrode, and generates an electric field between the common electrode and the first electrode to move the charged particles of the first display unit, or the common electrode An electric field is generated between the second electrode and the charged particles of the second display portion to move.

In the image display apparatus of the invention according to claim 4, in addition to the configuration of the invention according to claim 1, wherein the common electrode is an electrode in which a plurality of wires conduct current provided in parallel, the first The electrode is an electrode in which a plurality of conductors are arranged in parallel in a direction orthogonal to the plurality of conductors of the common electrode, and the second electrode is plural in a direction orthogonal to the plurality of conductors of the common electrode. Are arranged in parallel, and an electric field is generated between the common electrode and the first electrode to move the charged particles of the first display unit, or the common electrode An electric field is generated between the second electrode and the charged particles of the second display portion to move.

Further, in the image display device of the invention according to claim 5, in addition to the configuration of the invention according to any one of claims 1 to 4, the first electrode and the second electrode are translucent electrodes. It is characterized by being.

Further, in the image display device according to a sixth aspect of the invention, in addition to the configuration of the invention according to any one of the first to fifth aspects , the image display medium control means includes charged particles of the first display section. Electric power is supplied so as to have the same influence on the charged particles of the second display portion.

According to a seventh aspect of the present invention, in addition to the configuration of the sixth aspect of the invention, the image display medium control means applies an applied voltage for generating an electric field to the first display section. And the influence of the electric field on the second display unit and the influence of the electric field on the second display unit are controlled. It is characterized by being the same.

In the image display device according to an eighth aspect of the invention, in addition to the configuration of the invention according to the sixth aspect , the image display medium control means supplies a voltage for generating an electric field to the first display section. By controlling the application time and the voltage application time for generating the electric field to the second display unit, the influence of the electric field in the first display unit and the influence of the electric field in the second display unit are reduced. It is characterized by being the same.

In the image display device of the invention according to claim 9 , in addition to the configuration of the invention of claim 6 , the surface on the first display portion side or the surface on the second display portion side of the common substrate. The common electrode is provided, and, out of the first display unit and the second display unit, the concentration of charged particles in one display unit on the surface side of the common substrate on which the common electrode is provided. The charged particle concentration in the other display portion is larger.

According to a tenth aspect of the present invention, in addition to the configuration of any of the first to ninth aspects , the image display medium control means includes the first display section or the second display section. When an electric field is generated in the display unit, positive and negative electric fields are generated separately.

In the image display device according to the first aspect of the present invention, the first display substrate having the first electrode is provided so as to enclose the first display portion having charged particles facing the common substrate having the common electrode. A second display substrate having a second electrode is provided so as to enclose a second display portion having charged particles. Therefore, images can be displayed on both sides of one image display medium, and the manufacturing cost and the number of parts can be reduced by sharing one common electrode.
In addition, the image display apparatus can control the display mode of the image display medium, and can display images on both sides of one housing.
In addition, since the electric fields are separately generated in the first display unit and the second display unit, an image can be displayed on both sides of the housing even with one common electrode.
In addition, an image can be displayed on the other surface without affecting the image already displayed on one side, and the image can be accurately displayed on both sides of the housing.

In addition, in the image display device of the invention according to claim 2, in addition to the effect of the invention of claim 1, the common electrode as the drive side electrode, the first electrode and the second electrode as the ground side electrode, Thus, an electric field is generated to move the charged particles of the first display portion and the charged particles of the second display portion. Therefore, images can be displayed on both sides of one image display medium, and the manufacturing cost and the number of parts can be reduced by sharing one common electrode.

In the image display device of the invention according to claim 3, in addition to the effect of the invention of claim 1, the common electrode as the ground side electrode, the first electrode and the second electrode as the drive side electrode, Thus, an electric field is generated to move the charged particles of the first display portion and the charged particles of the second display portion. Therefore, images can be displayed on both sides of one image display medium, and the manufacturing cost and the number of parts can be reduced by sharing one common electrode.

Further, in the image display device according to the invention according to claim 4, in addition to the effect of the invention according to claim 1, the plurality of conductors orthogonal to the common electrode provided with the plurality of conductors and the conductor of the common electrode An electric field is generated between the first electrode and the second electrode on which are arranged to move the charged particles of the first display portion and the charged particles of the second display portion. Therefore, images can be displayed on both sides of one image display medium, and the manufacturing cost and the number of parts can be reduced by sharing one common electrode.

Further, in the image display device of the invention according to claim 5, in addition to the effects of the invention according to any one of claims 1 to 4, the first electrode and the second electrode are translucent electrodes. Images can be displayed on both sides of one image display medium.

In addition, in the image display device of the invention according to claim 6 , in addition to the effect of the invention according to any one of claims 1 to 5, the charged particles of the first display unit and the charged particles of the second display unit Since power is supplied so as to have the same influence, images with similar image quality can be displayed on both sides of one housing.

In the image display device of the invention according to claim 7 , in addition to the effect of the invention of claim 6 , the magnitude of the applied voltage to the first display section and the magnitude of the applied voltage to the second display section Is controlled so that the charged particles of the first display unit and the charged particles of the second display unit have the same influence, so that images of similar image quality can be displayed on both sides of one housing.

Further, in the image display device of the invention according to claim 8 , in addition to the effect of the invention of claim 6 , the application time of the voltage to the first display unit and the application time of the voltage to the second display unit Is controlled so that the charged particles of the first display unit and the charged particles of the second display unit have the same influence, so that images of similar image quality can be displayed on both sides of one housing.

In addition, in the image display device of the invention according to claim 9 , in addition to the effect of the invention of claim 6 , a common electrode is provided on one side of the common substrate, and the first display unit and the second display unit The charged particle concentration in the display portion on which the common electrode is provided is larger than the charged particle concentration in the other display portion. Therefore, images with similar image quality can be displayed on both sides of one housing.

In the image display device of the invention according to claim 10 , in addition to the effect of the invention according to any one of claims 1 to 9, when an electric field is generated in the first display unit or the second display unit, Since the electric field is generated separately for negative and negative, the image can be displayed on the other side without affecting the image already displayed on one side, and the image can be accurately displayed on both sides of the housing Can do.

  Hereinafter, a first embodiment of a display panel 1 that embodies an image display medium according to the present invention and a portable terminal device 2 that embodies an image display apparatus according to the present invention will be described with reference to the drawings. The display panel 1 exemplified as the present embodiment is a small display panel that can be provided in a portable electronic device, and the portable terminal device 2 is a portable electronic device such as an electronic book or PDA capable of displaying various images. .

  First, the outline of the structure of the display panel 1 and the portable terminal device 2 of this Embodiment is demonstrated with reference to drawings. FIG. 1 is a block diagram showing an electrical configuration of the display panel 1 and the portable terminal device 2, and FIG. 2 is a side sectional view showing a physical configuration of the display panel 1.

  As shown in FIG. 1, the display panel 1 is connected to a mobile terminal device 2, and image display on the display panel 1 is controlled by the mobile terminal device 2. The display panel 1 and the mobile terminal device 2 are electrically connected to each other at connection terminals 31 and 32 provided in each of them, and various signals and image information can be input and output. Thus, since the display panel 1 and the mobile terminal device 2 are configured independently, the user can carry the mobile terminal device 2 and connect it to the arbitrary display panel 1 to display an image. . In the present embodiment, in the display panel 1 and the mobile terminal device 2, the right direction in FIGS. 1 and 2 is the front direction, and the left direction is the back direction.

  As shown in FIGS. 1 and 2, a common substrate 10 provided vertically at a substantially central position in the front-rear direction (left-right direction in the drawing) of the display panel 1 is provided inside the display panel 1. The common substrate 10 which is a plate member having a predetermined width includes a common substrate layer 10a which is a member made of an insulating material, and a common drive electrode layer 10b on one surface of the common substrate layer 10a. The common substrate layer 10a is made of a material capable of exhibiting high insulation properties such as polyethylene terephthalate or glass, but is preferably made of a dielectric that allows a displacement current to pass but has a high resistance to a conductive current. . The common substrate layer 10a may be any color or transparent color, but is provided as a white member in the present embodiment. The common drive electrode layer 10 b is a drive side electrode that generates an electric field in the first display unit 12 or the second display unit 14. In the present embodiment, the common substrate layer 10a is a plastic substrate, the common drive electrode layer 10b is a drive circuit using a thin film transistor (TFT) as a drive element for active drive, and the back surface (second display) of the common substrate layer 10a. A surface facing the substrate 13).

  Next, the first display substrate 11 will be described. In the front direction of the common substrate 10 (right direction in the drawing), the first display substrate 11 is provided in parallel to the common substrate 10. The first display substrate 11 includes a first substrate layer 11a that is formed of a transparent member and functions as a display surface, and a first counter electrode layer 11b provided on the back surface (left side in the drawing) of the first substrate layer 11a. And are provided. The first substrate layer 11a is made of a material that can exhibit high transparency, such as polyethylene terephthalate or glass. The first counter electrode layer 11b is a ground side electrode for the common drive electrode layer 10b. In the present embodiment, the first substrate layer 11a is a transparent glass substrate, and the first counter electrode layer 11b is a transparent electrode formed of indium tin oxide (ITO). That is, since the first substrate layer 11a and the first counter electrode layer 11b are transparent bodies, the user passes through the first display substrate 11 from the front direction of the display panel 1 (the right direction in the drawing). 12 is visible.

  Next, the first display unit 12 will be described. A gap formed by the common substrate 10 and the first display substrate 11 that are provided to face each other and a gap spacer (not shown) that fixes the periphery of the common substrate 10 and the first display substrate 11 is formed in the first display unit 12. is there. The first display unit 12 is installed in a gap between the common substrate 10 and the first display substrate 11, and the gap is divided to form a plurality of small cells, and the common substrate 10 and the first display substrate 11. Are provided with a plurality of spacers 12c. The spacer 12c is a substantially rectangular plate-like member and may be made of a synthetic resin such as polyethylene terephthalate.

  The first display unit 12 is filled with a liquid dispersion medium 12a and charged particles 12b. As the liquid dispersion medium 12a, it is possible to use alcohols, hydrocarbons, silicone oils and the like that can exhibit high insulation properties and have low viscosity. The charged particles 12b are made of a material that can be charged in the liquid dispersion medium 12a, and are made of a pigment or dye made of an organic compound or an inorganic compound, or a pigment or dye wrapped with a synthetic resin. In the present embodiment, the liquid dispersion medium 12a is a white liquid made of alcohol, and the charged particles 12b are black particles in which carbon black is wrapped with a polyethylene resin.

  In such a configuration, the common drive electrode layer 10b functions as a drive-side electrode and the first counter electrode layer 11b functions as a ground-side electrode, and an electric field is generated in the first display unit 12 under the control of the display control unit 28. Let Then, the charged particles 12b charged positively or negatively move to the electrode side having the opposite polarity potential. And when this electrode side is the 1st display board | substrate 11, the black of the charged particle 12b is displayed in a front direction (right direction in a figure). When the direction of the electric field is reversed, the charged particles 12b move to the common substrate 10, and the white color of the liquid dispersion medium 12a is displayed in the front direction (right direction in the drawing).

  On the other hand, in the back direction of the common substrate 10 (left direction in the drawing), a second display substrate 13 is provided opposite to the common substrate 10 and in parallel with the common substrate 10. A gap formed by the common substrate 10 and the second display substrate 13 provided to face each other and a gap spacer (not shown) for fixing the periphery of the common substrate 10 and the second display substrate 13 is a second display unit. 14. The second display substrate 13 is provided with a second substrate layer 13a and a second counter electrode layer 13b. In addition, a plurality of spacers 14c are provided inside the second display unit 14, and are filled with the liquid dispersion medium 14a and the charged particles 14b. The second display substrate 13, the second substrate layer 13a, the second counter electrode layer 13b, the second display unit 14, the liquid dispersion medium 14a, the charged particles 14b, and the spacer 14c are the first display substrate 11 and the first substrate, respectively. The layer 11a, the first counter electrode layer 11b, the first display unit 12, the liquid dispersion medium 12a, the charged particles 12b, and the spacer 12c are the same members.

  In such a configuration, the common control electrode layer 10b functions as a drive-side electrode and the second counter electrode layer 13b functions as a ground-side electrode, and an electric field is generated in the second display unit 14 under the control of the display control unit 28. Let Then, the positively or negatively charged charged particles 14b move to the electrode side having the opposite polarity potential. When the electrode side is the second display substrate 13, the black color of the charged particles 14b is displayed in the back direction (left direction in the figure). Further, when the direction of the electric field is reversed, the charged particles 14b move to the common substrate 10, and the white color of the liquid dispersion medium 14a is displayed in the back direction (left direction in the figure).

  That is, in the portable display panel 1 of the present embodiment, each member such as the first display substrate 11 and the second display substrate 13, the first display unit 12 and the second display unit 14 is arranged in the front-rear direction around the common substrate 10. The configuration is provided symmetrically (in the horizontal direction in the figure). Then, the power supply to the common drive electrode layer 10b, the first counter electrode layer 11b, and the second counter electrode layer 13b is controlled, and the drive electrode position, the electric field strength, and the application are applied in the first display unit 12 and the second display unit 14. Arbitrary images can be displayed in the front direction and the back direction by adjusting the time or the like.

  Moreover, as shown in FIG. 1, the control part 20 which comprises the various functions for controlling the display panel 1 and the portable terminal device 2 is provided in the inside of the portable terminal device 2, and the control part 20 has the control. Is provided. The CPU 21 includes a ROM 22 that stores a program such as a BIOS executed by the CPU 21, a RAM 23 that temporarily stores data, an external interface 30 that inputs and outputs data, and a data storage device. Are connected to a hard disk drive (hereinafter referred to as “HDD”) 24. In addition, an input panel 26 provided with buttons and switches for a user to input various information to the mobile terminal device 2 and perform various operations in the mobile terminal device 2, and a key controller 25 for detecting these inputs, Are connected to the CPU 21 via the bus 27. Connected to the external interface 30 is a CD-ROM drive into which a CD-ROM as a data storage medium is inserted. The HDD 24 stores information input from the input panel 26, image information read from the CD-ROM drive, and the like. The external interface 30 can be connected to a memory card or a network in addition to the CD-ROM drive.

  In addition, a display control unit 28 that performs image display processing for displaying various images on the display panel 1 is connected to the CPU 21 via the bus 27, and is controlled by the display control unit 28 in the first display panel 1. A switch circuit 29 that switches the generation of an electric field in the display unit 12 or the second display unit 14 is provided. When the image display process is not executed, the switch circuit 29 is in a state in which neither SW1 nor SW2 is turned on, so that the entire display panel 1 is electrically disconnected.

  Note that the portable terminal device 2 may be provided with a floppy (registered trademark) disk drive (not shown), an input / output unit for sound, various interfaces, and the like. In addition, as described above, the display panel 1 and the mobile terminal device 2 are connected to each other via the connection terminals 31 and 32 and various signals and image information are input / output. An I / O interface (not shown) for output is provided on the display panel 1 and the portable terminal device 2. Further, image display on the display panel 1 is controlled by the display control unit 28, and a display control program (not shown) for controlling the display control unit 28 to display various images on the display panel 1 is stored in the ROM 22. Is done.

  Next, details of the configuration of each substrate (the common substrate 10, the first display substrate 11, and the second display substrate 13) constituting the display panel 1 will be described. 3 is a front view of the common substrate 10, and FIG. 4 is a front view of the first display substrate 11 (second display substrate 13).

  As shown in FIG. 3, the common substrate 10 has a common drive electrode layer 10b on the back surface (a surface facing the second display substrate 13) of the common substrate layer 10a which is a plastic substrate formed in a substantially square shape when viewed from the front. Provided. In the common drive electrode layer 10b, a conducting wire (not shown) for conducting a current is wound on the lattice, and a thin film transistor (TFT) as an active element is provided at each position where the conducting wires intersect.

  As shown in FIG. 4, the first display substrate 11 has indium tin oxide (ITO) on the back surface (surface facing the common substrate 10) of the first substrate layer 11a, which is a glass substrate formed in a substantially square shape when viewed from the front. ) To form a first counter electrode layer 11b. The first counter electrode layer 11b functions as a ground-side electrode for the common drive electrode layer 10b, and generates an electric field in the first display unit 12 with the common drive electrode layer 10b. Similarly, the second display substrate 13 is also provided with a second counter electrode layer 13b formed of indium tin oxide (ITO) on the front surface (the surface facing the common substrate 10) of the second substrate layer 13a which is a glass substrate. It is done. The second counter electrode layer 13b functions as a ground-side electrode for the common drive electrode layer 10b, and generates an electric field in the second display unit 14 with the common drive electrode layer 10b.

  In such a display panel 1, when an electrical signal is sent to the grid-like conductors (not shown) of the common drive electrode layer 10b at the vertical and horizontal timings, the thin film transistor (TFT) at the position where the conductors intersect is driven. Then, an electric field is generated in the first display unit 12 provided between the common substrate 10 (FIG. 3) and the first display substrate 11 (FIG. 4) facing each other, and the charged particles 12b (FIG. 2) are shared. The substrate 10 or the first display substrate 11 is moved. Further, an electric field is generated in the second display portion 14 provided between the opposing common substrate 10 (FIG. 3) and the second display substrate 13 (FIG. 4), and the charged particles 14b (FIG. 2) are shared. Move to the substrate 10 or the second display substrate 13. That is, the display panel 1 performs a display operation by a so-called active matrix driving method.

  Next, image display operations in the display panel 1 and the mobile terminal device 2 of the present embodiment will be described with reference to the drawings. FIG. 5 is a block diagram showing the electrical configuration when displaying an image in the front direction, FIG. 6 is a side sectional view showing the physical configuration when displaying the image in the front direction, and FIG. 7 is the image display operation in the front direction. It is a figure for demonstrating. 8 is a block diagram showing an electrical configuration when displaying an image in the rear direction, FIG. 9 is a side sectional view showing a physical configuration when displaying an image in the rear direction, and FIG. 10 is an image display in the rear direction. It is a figure for demonstrating operation | movement.

  In the present embodiment, when an instruction to display a predetermined image based on the image information stored in the HDD 24 is given in the mobile terminal device 2, the display panel 1 first starts with respect to the front direction (first display substrate 11). Then, the image is displayed, and thereafter, an image having the same image quality as that of the image is displayed in the rear direction (second display substrate 13), and double-sided display is executed on the display panel 1. Needless to say, the image in the front direction and the image in the back direction may be different.

  As shown in FIG. 5, first, “SW1” is turned ON in the switch circuit 29 by the display control unit 28, and a voltage is applied to the common drive electrode layer 10b. Then, an electric field is generated in the first display unit 12 provided between the common drive electrode layer 10b of the common substrate 10 and the first counter electrode layer 11b of the first display substrate 11. On the other hand, since “SW2” is turned off in the switch circuit 29, the second counter electrode layer 13b of the second display substrate 13 is in an electrically disconnected state, so that no electric field is generated in the second display unit. .

  As shown in FIG. 6, when an electric field is generated in the first display unit 12, the charged particles 12 b charged positively or negatively move in the direction of the common substrate 10 or the first display substrate 11 according to the direction of the electric field. To do. Specifically, when the charged particles 12b are positively charged, if the common drive electrode layer 10b is a cathode and the first counter electrode layer 11b is an anode, the electric field is the first counter electrode layer 11b → the common drive electrode layer. 10b, the charged particles 12b move in the direction of the common drive electrode layer 10b. Conversely, if the common drive electrode layer 10b is an anode and the first counter electrode layer 11b is a cathode, the electric field is directed from the common drive electrode layer 10b to the first counter electrode layer 11b, and the charged particles 12b are transferred to the first counter electrode layer 11b. Move in the direction of. When the charged particles 12b are negatively charged, the charged particles 12b move toward the anode substrate. When the charged particles 12b move in the direction of the first display substrate 11, the user can visually check the black color of the charged particles 12b from the front direction of the first display substrate 11 (right direction in the drawing). On the other hand, when the charged particles 12b move in the direction of the common substrate 10, the white color of the liquid dispersion medium 12a is displayed to the user.

  In the mobile terminal device 2, the display control unit 28 is controlled based on the image information to be displayed by the display control program stored in the ROM 22, and an electric field is generated in the display panel 1 by the display control unit 28. Thereby, the polarity is controlled for each of the plurality of thin film transistors (TFTs) provided in the common drive electrode layer 10b, and the charged particles 12b are moved to positions necessary for image display. As a result, a predetermined image is displayed in the front direction (right direction in the drawing) of the first display substrate 11.

  Note that after a predetermined image is displayed by the above-described image display operation, even if voltage application is stopped, the image is maintained as it is because of hysteresis characteristics.

  Details of the image display operation will be described with reference to FIG. When the charged particles 12b are positively charged, the electrodes A, B, and C are provided on the common drive electrode layer 10b, and an image is displayed in the front direction of the first display substrate 11 (right direction in the figure). Is illustrated.

  First, a voltage is applied so that a potential of +10 V is applied to the electrode A corresponding to a position where an image (pixel) is displayed. At the same time, a voltage is applied to the electrode C so as to give a potential of + 10V. Then, the charged particles 12b existing in the vicinity of the electrode A (electrode C) move in the direction of the first counter electrode layer 11b facing the electrode A (electrode C). Next, a voltage is applied to the electrode B that does not display an image (pixel) so as to apply a potential of −10V. Then, the charged particles 12b existing in the vicinity of the electrode B move in the direction of the electrode B. Note that either the application of the common drive electrode layer 10b as a positive potential or the application of a negative potential may be preceded.

  As described above, the application in which each electrode of the common drive electrode layer 10b is positive and the application in which each electrode of the common drive electrode layer 10b is negative are executed at different timings. In other words, the common drive electrode layer 10b is controlled so as not to have a positive and negative potential at the same time. This is because when the electrode having a positive potential and the electrode having a negative potential in the common drive electrode layer 10b simultaneously generate an electric field between the first counter electrode layer 11b, the unconnected (ground side) first electrode. Also in the second counter electrode layer 13b, a current flows along the conductor, and a closed circuit is formed between the common drive electrode layer 10b and the first counter electrode layer 11b. This is to prevent the particles 14b from moving. Thus, a predetermined image can be formed on the first display unit 12 without affecting the second display unit 14.

  Next, as shown in FIG. 8, “SW2” is turned ON in the switch circuit 29 by the display control unit 28, and a voltage is applied to the common drive electrode layer 10b. Then, an electric field is generated in the second display portion 14 provided between the common drive electrode layer 10b of the common substrate 10 and the second counter electrode layer 13b of the second display substrate 13. On the other hand, since “SW1” is turned off in the switch circuit 29, the first counter electrode layer 11b of the first display substrate 11 is in an electrically disconnected state, so that no electric field is generated in the first display unit 12. .

  As shown in FIG. 9, when an electric field is generated in the second display unit 14, the charged particles 14 b charged positively or negatively move in the direction of the common substrate 10 or the second display substrate 13 according to the direction of the electric field. To do. Specifically, when the charged particles 14b are positively charged, if the common drive electrode layer 10b is a cathode and the second counter electrode layer 13b is an anode, the electric field is transferred from the second counter electrode layer 13b to the common drive electrode layer. 10b, the charged particles 14b move toward the common drive electrode layer 10b. Conversely, if the common drive electrode layer 10b is an anode and the second counter electrode layer 13b is a cathode, the electric field is directed from the common drive electrode layer 10b to the second counter electrode layer 13b, and the charged particles 14b are transferred to the second counter electrode layer 13b. Move in the direction of. When the charged particles 14b are negatively charged, the charged particles 14b move toward the anode substrate. When the charged particles 14b move in the direction of the second display substrate 13, the user can visually check the black color of the charged particles 14b from the back direction of the second display substrate 13 (left direction in the figure). On the other hand, when the charged particles 14b move in the direction of the common substrate 10, the white color of the liquid dispersion medium 14a is displayed to the user.

  In the mobile terminal device 2, the display control unit 28 is controlled based on the image information to be displayed by the display control program stored in the ROM 22, and an electric field is generated in the display panel 1 by the display control unit 28. Thereby, the polarity is controlled for each of the plurality of thin film transistors (TFTs) provided in the common drive electrode layer 10b, and the charged particles 14b are moved to positions necessary for image display. As a result, a predetermined image is displayed in the back direction (left direction in the drawing) of the second display substrate 13.

  Details of the image display operation will be described with reference to FIG. When the charged particles 14b are positively charged, the electrodes A, B, and C are provided on the common drive electrode layer 10b, and an image is displayed in the back direction (left direction in the drawing) of the second display substrate 13. Is illustrated.

  First, a voltage is applied so that a potential of +10 V is applied to the electrode A corresponding to a position where an image (pixel) is displayed. At the same time, a voltage is applied to the electrode C so as to give a potential of + 10V. Then, the charged particles 14b existing in the vicinity of the electrode A (electrode C) move in the direction of the second counter electrode layer 13b facing the electrode A (electrode C). Next, a voltage is applied to the electrode B that does not display an image (pixel) so as to apply a potential of −10V. Then, the charged particles 14 b existing in the vicinity of the electrode B move in the direction of the electrode B. Note that either the application of the common drive electrode layer 10b as a positive potential or the application of a negative potential may be preceded.

  In this way, as in FIG. 7, the application in which each electrode of the common drive electrode layer 10b is positive and the application in which each electrode of the common drive electrode layer 10b is negative are controlled at different timings. Therefore, a predetermined image can be formed on the second display unit 14 without affecting the first display unit 12. In particular, an image has already been formed on the first display unit 12, and there is a risk that the image will be destroyed if the first display unit 12 is affected by an electric field. However, the above operation has no effect on the first display unit 12. An image can be formed on the second display unit 14 without giving.

  By the way, the same electric field needs to be generated in the first display unit 12 and the second display unit 14. Specifically, the electric field strengths in the first display unit 12 and the second display unit 14 are the same, the polarity in the common drive electrode layer 10b is the same, and the polarity in the first counter electrode layer 11b and the second counter electrode. The polarity in the electrode layer 13b needs to be symmetrical in the front-rear direction (left-right direction in the drawing) with respect to the common substrate 10. As a result, the charged particles 12b and the charged particles 14b are moved so as to be symmetrical in the front-rear direction (left-right direction in the figure) about the common substrate 10, and images of similar image quality are displayed on both surfaces of the display panel 1. Can be displayed.

  On the other hand, since the common drive electrode layer 10b is provided on one side of the common substrate layer 10a, the common drive electrode layer 10b serving as the ground side electrode is changed from the common drive electrode layer 10b serving as the drive side electrode depending on the width (thickness) of the common substrate layer 10a. The distances between the first counter electrode layer 11b and the second counter electrode layer 13b are different. That is, since the first counter electrode layer 11b is located farther than the second counter electrode layer 13b when viewed from the common drive electrode layer 10b, the first display can be performed even if a voltage having the same strength is applied to each of them. The electric field strength in the portion 12 is smaller than the electric field strength in the second display portion 14. Therefore, the same electric field strength is generated in the first display unit 12 and the second display unit 14 by the following means.

(1) Adjustment of applied voltage When an electric field is generated on the first display unit 12, the voltage application time is the same as that when an electric field is generated on the second display unit 14, but a larger voltage is applied. By adjusting the voltage applied to the common drive electrode layer 10b, the first counter electrode layer 11b, and the second counter electrode layer 13b, the electric field strengths in the first display unit 12 and the second display unit 14 can be made the same. . This adjustment is executed by the display control unit 28 controlled by the display control program. At this time, it is necessary to consider the distance between the electrodes and the dielectric constant of various members in between. For example, 10 V is applied for 5 μs when an electric field is generated on the first display unit 12, and 8 V is applied for 5 μs when an electric field is generated on the second display unit 14.

(2) Adjustment of application time When an electric field is generated on the first display unit 12, the voltage value is the same as that when an electric field is generated on the second display unit 14, but a longer time voltage is applied. By adjusting the application time to the common drive electrode layer 10b, the first counter electrode layer 11b, and the second counter electrode layer 13b, the electric field strengths in the first display unit 12 and the second display unit 14 can be made the same. it can. This adjustment is executed by the display control unit 28 controlled by the display control program. At this time, it is necessary to consider the distance between the electrodes and the dielectric constant of various members in between. For example, 10 V is applied for 5 μs when an electric field is applied to the first display unit 12, and 10 V is applied for 4 μs when an electric field is generated for the second display unit 14.

(3) Adjustment of the composition concentration The composition concentration of the charged particles 12b in the first display unit 12 (the ratio of the charged particles 12b to the liquid dispersion medium 12a) is larger than the composition concentration of the charged particles 14b in the second display unit 14 The 1st display part 12 and the 2nd display part 14 are comprised so that it may become a value. Thereby, even if the voltage of the same voltage value and the same application time is applied to each, the electric field strength in the 1st display part 12 and the 2nd display part 14 can be made the same. This adjustment of the composition concentration takes into account the difference in distance from the common drive electrode layer 10b to each of the first counter electrode layer 11b and the second counter electrode layer 13b when the display panel 1 is manufactured. A person may set the composition concentration in the first display unit 12 and the second display unit 14 arbitrarily. At this time, it is necessary to consider the distance between the electrodes and the dielectric constant of various members in between.

  By the means as described above, the same electric field strength can be generated in the first display unit 12 and the second display unit 14, and the charged particles 12b and the charged particles 14b can be similarly affected. Therefore, even when one common drive electrode layer 10b is provided only on one side of the common substrate layer 10a, it is possible to reliably display images with the same image quality on both sides of the display panel 1.

  As described above, according to the display panel 1 and the mobile terminal device 2 of the first embodiment, the electric field is generated in the first display unit 12 by the common drive electrode layer 10b and the first counter electrode layer 11b, and the charged particles 12b are generated. While moving and displaying a predetermined image in the front direction of the first display substrate 11, an electric field is generated in the second display unit 14 by the common drive electrode layer 10b and the two counter electrodes 13b to move the charged particles 14b. A predetermined image is displayed in the back direction of the second display substrate 13. Therefore, it is possible to display images on both surfaces of one display panel 1 and to share one common drive electrode layer 10b, thereby reducing the number of parts and the manufacturing cost.

  Moreover, since the same electric field can be generated in the first display unit 12 and the second display unit 14 and the charged particles 12b and the charged particles 14b can be similarly affected, the charged particles 12b and the charged particles 14b The common substrate 10 is moved so as to be symmetrical in the front-rear direction (left-right direction in the figure). Therefore, it is possible to display images having the same image quality on both surfaces of one display panel 1 and prevent the colors and images from being inverted.

  In addition, after the image display is executed on the first display substrate 11, the image display operation on the second display substrate 13 is executed in a state where the displayed image is maintained by the hysteresis characteristic, and the second display is performed. During the execution of the image display operation on the substrate 13, the first counter electrode layer 11b is in an electrically disconnected state. Therefore, the image display operation of the second display substrate 13 does not adversely affect the image previously displayed on the first display substrate 11, so that images with the same image quality can be accurately displayed on both surfaces of one display panel 1. Can be displayed.

  Further, since the common substrate 10 has a simple configuration in which the common drive electrode layer 10b is provided on one surface of the common substrate layer 10a, the display panel 1 can be easily manufactured, and the number of components and the manufacturing cost can be reduced. .

  Next, a second embodiment according to the present invention will be described with reference to the drawings. The display panel 1 and the mobile terminal device 2 in the present embodiment are basically the same as those in the first embodiment, but the configuration of the display panel 1 is different. FIG. 11 is a side sectional view showing a physical configuration of the display panel 1 in the second embodiment. FIG. 12 is a front view of the common substrate 10 in the second embodiment. FIG. 13 is a front view of the first display substrate 11 (second display substrate 13) in the second embodiment.

  As shown in FIGS. 11 and 12, the common substrate 10 has an indium tin oxide (ITO) layer on the back surface (a surface facing the second display substrate 13) of the common substrate layer 10a, which is a substantially square plastic substrate, as viewed from the front. A common counter electrode layer 10c formed by the above is provided. The common counter electrode layer 10c functions as a ground-side electrode for the first drive electrode layer 11c or the second drive electrode layer 13c, and the first display is performed by applying a voltage from the first drive electrode layer 11c or the second drive electrode layer 13c. An electric field is generated in the unit 12 or the second display unit 14.

  As shown in FIGS. 11 and 13, the first display substrate 11 has a first drive electrode layer on a back surface (a surface facing the common substrate 10) of the first substrate layer 11 a which is a substantially square glass substrate when viewed from the front. 11c is provided. Similarly, the second display substrate 13 is provided with a second drive electrode layer 13c on the front surface (the surface facing the common substrate 10) of the second substrate layer 13a which is a glass substrate. In the first drive electrode layer 11c and the second drive electrode layer 13c, a conducting wire for guiding a current is wound around the lattice, and a thin film transistor (TFT) as an active element is provided for each lattice formed by the conducting wire. .

  As described above, in the display panel 1 of the present embodiment, contrary to the first embodiment, the ground-side electrode is provided on the common substrate 10, and the first display substrate 11 and the second display substrate 13 are driven. An electrode is provided. As in the first embodiment, when “SW1” is turned ON in the switch circuit 29 by the display control unit 28 and a voltage is applied to the first drive electrode layer 11c (see FIG. 5), the first display is performed. An electric field is generated in the portion 12, and a predetermined image is displayed in the front direction (right direction in the drawing) of the first display substrate 11. After that, when “SW2” is turned ON in the switch circuit 29 by the display control unit 28 and a voltage is applied to the second drive electrode layer 13c (see FIG. 8), an electric field is generated in the second display unit 14, 2 A predetermined image is displayed with respect to the back direction of the display substrate 13 (left direction in the figure).

  As described above, according to the display panel 1 and the mobile terminal device 2 of the second embodiment, a predetermined image is displayed in the front direction of the first display substrate 11, while the predetermined direction is also displayed in the back direction of the second display substrate 13. Since the image is displayed, the image can be displayed on both surfaces of one display panel 1 and the common counter electrode layer 10c is shared, so that the number of parts and the manufacturing cost can be reduced.

  Next, a third embodiment according to the present invention will be described with reference to the drawings. The display panel 1 and the mobile terminal device 2 in the present embodiment are basically the same as those in the first and second embodiments, but the configuration of the display panel 1 is different. FIG. 14 is a side sectional view showing a physical configuration of the display panel 1 in the third embodiment. FIG. 15 is a front view of the common substrate 10 according to the third embodiment. FIG. 16 is a front view of the first display substrate 11 (second display substrate 13) in the third embodiment.

  As shown in FIGS. 14 and 15, the common substrate 10 has a common Y electrode layer 10 d on the back surface (a surface facing the second display substrate 13) of the common substrate layer 10 a which is a substantially square plastic substrate when viewed from the front. Provided. In the common Y electrode layer 10d, a plurality of conducting wires for guiding current are arranged in parallel in the vertical direction (Y direction).

  As shown in FIGS. 14 and 16, the first display substrate 11 has a first X electrode layer 11d on the back surface (a surface facing the common substrate 10) of the first substrate layer 11a which is a substantially square glass substrate when viewed from the front. Is provided. Similarly, the second display substrate 13 is provided with a second X electrode layer 13d on the back surface (the surface facing the common substrate 10) of the second substrate layer 13a. In the first X electrode layer 11d and the second X electrode layer 13d, a plurality of conducting wires for guiding current are arranged in parallel in the horizontal direction (X direction).

  In such a display panel 1, the common Y electrode layer 10 d and the first X electrode layer 11 d (second X electrode layer 13 d) have a grid shape in which the conductive wires intersect with each other, and each of the conductive wires has an electrical signal at a predetermined timing. Is sent, a voltage is applied at the position where the conductors cross. Then, an electric field is generated in the first display unit 12 provided between the common substrate 10 (FIG. 15) and the first display substrate 11 (FIG. 16) facing each other, and the charged particles 12b (FIG. 14) are shared. The substrate 10 or the first display substrate 11 is moved. Further, an electric field is generated in the second display section 14 provided between the common substrate 10 (FIG. 15) and the second display substrate 13 (FIG. 16) facing each other, and the charged particles 14b (FIG. 14) are shared. Move to the substrate 10 or the second display substrate 13. In other words, the display panel 1 performs a display operation by a so-called simple matrix driving method.

  Then, as in the first embodiment, when “SW1” is turned on in the switch circuit 29 by the display control unit 28 and a voltage is applied to the common Y electrode layer 10d and the first X electrode layer 11d (see FIG. 5). ), An electric field is generated in the first display unit 12, and a predetermined image is displayed in the front direction of the first display substrate 11 (right direction in the drawing). After that, when “SW2” is turned on in the switch circuit 29 by the display control unit 28 and a voltage is applied to the common Y electrode layer 10d and the second X electrode layer 13d (see FIG. 8), an electric field is applied to the second display unit 14. It occurs and a predetermined image is displayed in the back direction (left direction in the figure) of the second display substrate 13.

  As described above, according to the display panel 1 and the mobile terminal device 2 of the third embodiment, a predetermined image is displayed in the front direction of the first display substrate 11, while the predetermined direction is also displayed in the back direction of the second display substrate 13. Since an image is displayed, an image can be displayed on both surfaces of one display panel 1, and the number of parts and manufacturing cost can be further reduced by a simple matrix driving method that does not require a thin film transistor (TFT).

  By the way, in the first to third embodiments, the first display unit 12 corresponds to the “first display unit” of the present invention, and the second display unit 14 corresponds to the “second display unit” of the present invention. It corresponds to. The common substrate 10 corresponds to the “common substrate” of the present invention, and the common drive electrode layer 10b, the common counter electrode layer 10c, and the common Y electrode layer 10d correspond to the “common electrode” of the present invention. The first display substrate 11 corresponds to the “first display substrate” of the present invention, and the first counter electrode layer 11b, the first drive electrode layer 11c, and the first X electrode layer 11d are the “first electrode” of the present invention. It corresponds to. The second display substrate 13 corresponds to the “second display substrate” of the present invention, and the second counter electrode layer 13b, the second drive electrode layer 13c, and the second X electrode layer 13d are the “second electrode” of the present invention. It corresponds to.

  Further, the display control unit 28 and the switch circuit 29 correspond to the “image display medium control unit” of the present invention, the connection terminal 32 corresponds to the “electrical connection unit” of the present invention, and the control unit 20 corresponds to the “image display medium control unit” of the present invention. It corresponds to "control body".

  The present invention is not limited to the embodiment described in detail above, and it goes without saying that various modifications are possible.

  In the first to third embodiments, in the common substrate 10, various common electrodes (common drive electrode layer 10 b, common counter electrode layer) are provided on the back surface of the common substrate layer 10 a (surface facing the second display substrate 13). 10c and the common Y electrode layer 10d), various common electrodes may be provided on the front surface of the common substrate layer 10a (the surface facing the first display substrate 11).

  Various common electrodes may be provided at the center of the cross section of the common substrate layer 10a. In this case, since the distance from the various common electrodes to the electrode provided on the first substrate 11 is equal to the distance from the various common electrodes to the electrode provided on the second substrate 13, the application is performed as described above. There is no need to adjust voltage, application time, charged particle concentration, etc.

  In the first to third embodiments, after a predetermined image is displayed in the front direction (first display substrate 11), an image having the same image quality is displayed in the rear direction (second display substrate 13). However, an image with the same image quality may be displayed in the front direction (first display substrate 11) after the predetermined image is displayed in the rear direction (second display substrate 13). Furthermore, the image in the front direction and the image in the back direction need not be the same, and different images may be displayed.

  The switch circuit 29 is not limited to switching the application to the other after the image is completely displayed on the one as in the above embodiment, and the application can be switched at an arbitrary timing. For example, if it is applied to one side for a predetermined time, the application is switched to the other even during the image display. And if it applies to the other for a predetermined time, even if it is in the middle of an image display, an application is switched to one. In this way, the images may be displayed on both sides of the display panel 1 by alternately switching the application.

  In the third embodiment, the common Y electrode layer 10d is a common X electrode layer in which conductive wires are provided in the horizontal direction, and the first X electrode layer 11d (second X electrode layer 13d) is provided in the vertical direction. As the first Y electrode layer (second Y electrode layer), the direction in which the respective conductors intersect may be reversed. That is, the common substrate 10 and the first display substrate 11 (second display substrate 13) are electrodes having a matrix structure in which conductors are disposed on the other substrate in a direction perpendicular to the conductors disposed on one substrate. Should just be formed.

  Further, the electrophoretic image display medium and the image display apparatus to which the present invention is applied are not limited to those shown in the above-described embodiments, and can be applied to various types. For example, a display unit filled with a liquid dispersion medium containing charged particles is provided with various members such as a spherical body, a microcapsule, and a plate-like member, or two types of charged particles having different polarities, The present invention can also be applied to an electrophoretic image display medium capable of color display and an image display device.

Images display device of the present invention, as images display device electrophoretic, can be applied to various electronic devices to perform a liquid crystal monitor, a cellular phone, a personal computer, an electronic book, an image display such as a PDA.

3 is a block diagram showing an electrical configuration of a display panel 1 and a mobile terminal device 2. FIG. 3 is a side sectional view showing a physical configuration of the display panel 1. FIG. 2 is a front view of a common substrate 10. FIG. It is a front view of the 1st display substrate 11 (2nd display substrate 13). It is a block diagram which shows the electrical structure in the case of displaying an image in the front direction. It is side surface sectional drawing which shows the physical structure in the case of displaying an image in the front direction. It is a figure for demonstrating the image display operation | movement to a front direction. It is a block diagram which shows the electrical structure in the case of displaying an image in the back direction. It is side surface sectional drawing which shows the physical structure in the case of displaying an image in a back direction. It is a figure for demonstrating the image display operation | movement to a back direction. It is side surface sectional drawing which shows the physical structure of the display panel 1 in 2nd Embodiment. It is a front view of the common board | substrate 10 in 2nd Embodiment. It is a front view of the 1st display board 11 (2nd display board 13) in a 2nd embodiment. It is side surface sectional drawing which shows the physical structure of the display panel 1 in 3rd Embodiment. It is a front view of the common board | substrate 10 in 3rd Embodiment. It is a front view of the 1st display substrate 11 (2nd display substrate 13) in a 3rd embodiment. It is a figure for demonstrating the prior art. It is a figure for demonstrating the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display panel 2 Portable terminal device 10 Common board | substrate 10a Common board | substrate layer 10b Common drive electrode layer 10c Common counter electrode layer 10d Common Y electrode layer 11 1st display board 11a 1st board | substrate layer 11b 1st counter electrode layer 11c 1st drive electrode Layer 11d first X electrode layer 12 first display portion 12a liquid dispersion medium 12b charged particles 12c spacer 13 second display substrate 13a second substrate layer 13b second counter electrode layer 13c second drive electrode layer 13d second X electrode layer 14 second Display unit 14a Liquid dispersion medium 14b Charged particle 14c Spacer 20 Control unit 21 CPU
22 ROM
23 RAM
24 HDD
25 Key Controller 26 Input Panel 27 Bus 28 Display Control Unit 29 Switch Circuit 30 External Interface 31 Connection Terminal 32 Connection Terminal

Claims (10)

A first display unit having charged particles that move in accordance with the direction of the electric field;
A second display section provided opposite to the first display section and having charged particles that move according to the direction of the electric field;
A common substrate provided in common to the first display portion and the second display portion, and having a common electrode used in common for the first display portion and the second display portion;
A first display substrate having a first electrode provided so as to enclose the charged particles of the first display portion between the common substrate and the common substrate;
A second display substrate having a second electrode provided so as to enclose charged particles of the second display portion between the common substrate and the common substrate ;
Image display medium control for supplying electric power to the common electrode and the first electrode or the second electrode so that an electric field is separately generated in the first display unit and the second display unit Means and
The image display medium control means controls the second electrode to be electrically disconnected when generating an electric field in the first display unit, and generates the electric field in the second display unit. An image display device, wherein the first electrode is controlled to be electrically disconnected. The common electrode functions as a drive side electrode,
The first electrode functions as a ground electrode for the common electrode;
The second electrode functions as a ground electrode for the common electrode,
An electric field is generated between the common electrode and the first electrode to move the charged particles of the first display unit, or an electric field is generated between the common electrode and the second electrode. The image display apparatus according to claim 1, wherein the charged particles of the second display unit are moved. The common electrode functions as a ground side electrode,
The first electrode functions as a drive side electrode;
The second electrode functions as a drive side electrode;
An electric field is generated between the common electrode and the first electrode to move the charged particles of the first display unit, or an electric field is generated between the common electrode and the second electrode. The image display apparatus according to claim 1, wherein the charged particles of the second display unit are moved. The common electrode is an electrode in which a plurality of conducting wires for conducting current are arranged in parallel,
The first electrode is an electrode in which a plurality of conductors are arranged in parallel in a direction orthogonal to the plurality of conductors of the common electrode,
The second electrode is an electrode in which a plurality of conductors are arranged in parallel in a direction orthogonal to the plurality of conductors of the common electrode,
An electric field is generated between the common electrode and the first electrode to move the charged particles of the first display unit, or an electric field is generated between the common electrode and the second electrode. The image display apparatus according to claim 1, wherein the charged particles of the second display unit are moved. The image display device according to claim 1, wherein the first electrode and the second electrode are translucent electrodes. The image display medium control means according to claim 1, wherein the supplying power to provide the same effect on the charged particles of the second display unit and the charged particles of the first display unit An image display device according to any one of the above. The image display medium control means controls a magnitude of an applied voltage for generating an electric field to the first display section and a magnitude of an applied voltage for generating an electric field to the second display section, The image display device according to claim 6 , wherein the influence of the electric field in the first display section is the same as the influence of the electric field in the second display section. The image display medium control means controls a voltage application time for generating an electric field to the first display unit and a voltage application time for generating an electric field to the second display unit, The image display device according to claim 6 , wherein the influence of the electric field in the first display section is the same as the influence of the electric field in the second display section. The common electrode is provided on the first display unit side surface or the second display unit side surface of the common substrate,
Of the first display unit and the second display unit, the charged particle concentration in the other display unit is higher than the charged particle concentration in one display unit on the surface side where the common electrode is provided on the common substrate. The image display apparatus according to claim 6 , wherein the density is higher. 10. The image display medium control unit according to claim 1, wherein when the electric field is generated in the first display unit or the second display unit, the electric field is generated separately for positive and negative . The image display device according to any one of the above.