JP2007279318A - Drive device for image display medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive device for an image display medium by which particles can sufficiently be driven and dot defects can be prevented. <P>SOLUTION: The drive device for driving the image display medium including a display substrate, a rear substrate, and at least one kind of particle groups which are sealed between both substrates so as to move in accordance with an electric field generated between the substrates by applying a voltage corresponding to image data between a plurality of scan electrodes 14 and a plurality of opposed data electrodes 20 crossing the scan electrodes is provided with: a voltage applying means which applies the voltage between the scan electrodes 14 and the data electrodes 20; and a control means which controls the voltage applying means so as to repeat a scan sequence of selecting at least two scan electrodes out of the plurality of scan electrodes 14 as a scan electrode group and scanning the selected scan electrode group a plurality of times and then shifting scan electrodes by a prescribed number of scan electrodes downstream in a scanning direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image display medium driving apparatus, and more particularly to an image display medium driving apparatus capable of repeatedly rewriting to display an image by moving colored particles by applying a voltage between substrates.

  2. Description of the Related Art Conventionally, an image display medium using colored particles is known as an image display medium that has a memory property and can be rewritten repeatedly. Such an image display medium includes, for example, a pair of substrates and a plurality of types of particle groups that are sealed between the substrates so as to be movable between the substrates by an applied electric field and have different colors and charging characteristics. Is done. In addition, a gap member for partitioning the substrates into a plurality of cells is provided between the substrates for the purpose of preventing the particles from being biased to a partial region in the substrates.

  In such an image display medium, particles are moved by applying a voltage corresponding to the image between the pair of substrates, and an image is displayed as the contrast of particles of different colors. Even after the application of the voltage is stopped, the particles remain attached to the substrate by van der Waals force or mirror image force, and the image display is maintained.

  When an attempt is made to increase the resolution of such an image display medium, the pixels (dots) to be displayed are reduced, and the number of particles existing between the substrates of one pixel is also reduced. When the number of particles decreases, the number of particles that move easily due to the electric field therein decreases, and when the electric field for displaying an image is formed between the substrates, the knock-out effect by the particles that move easily decreases. For this reason, there existed a problem that display density became inadequate or a particle | grain did not move at all and it became easy to generate | occur | produce a dot-like display defect.

  Here, the knockout effect will be described. Particles vary in size, shape, and amount of charge, so there is variation in adhesion to the substrate and electrostatic force received from the electric field formed between the substrates, and movement when an electric field for displaying an image is formed There are variations in ease. When an electric field for image display is formed, the mobile particles first move between the substrates and collide with the hard-moving particles adhering to the opposing substrate, and this impact force triggers the hard-moving particles. It can be moved out and moved, and this is repeated to drive most of the particles. This is called the knockout effect.

  By the way, Patent Document 1 proposes an image display medium that has a configuration in which the color of the back substrate and the color of the particle group are different and displays an image with a contrast between the color of the particle and the color of the back substrate.

  In this image display medium, for example, for a pixel for which the color of a particle is to be displayed, the particle is moved to the display substrate side by applying, for example, a DC voltage between the substrates at that position. On the other hand, with respect to a pixel for which the color of the back substrate is to be displayed, an alternating voltage is applied between the substrates at that position to move the particles back and forth between the substrates and move to other pixel regions to expose the back substrate. .

  Such an image display medium has the following problems in addition to the problem that the dot-like display defect is likely to occur.

  For example, in the case of increasing the resolution of an image display medium having a so-called simple matrix structure electrode, a configuration in which each pixel is surrounded by a gap member, that is, if one cell is configured by one pixel is sufficient because the aperture ratio decreases. Display contrast cannot be obtained. Therefore, the aperture ratio is improved if a configuration in which a plurality of pixels are surrounded by a gap member, that is, one cell is configured by a plurality of pixels.

  However, when one cell is configured to include a plurality of pixels in the scanning direction, when the color of the back substrate is displayed continuously in the scanning direction, some of the removed particles are upstream in the scanning direction, that is, once the particles There is a problem in that the color of the rear substrate cannot be displayed sufficiently because it returns to the area where the film is removed.

  For example, an image display medium that includes two types of particles of white particles and black particles and can display three colors in which the color of the back substrate is red will be described. As shown in FIG. 12, in an image display medium having a so-called simple matrix structure in which a plurality of scanning electrodes 100 and a plurality of data electrodes 102 are arranged so as to be orthogonal to each other, the gap member 104 is shaped as shown in FIG. When the gap member 104 is provided between the pixels in the scanning direction S, as shown in FIGS. 13 and 14, even when the pixels 106 displaying the color of the back substrate (for example, red) are continuous in the scanning direction. Since the movement of the particles is limited by the gap member 104, the color of the back substrate can be sufficiently displayed.

  However, in order to prevent a decrease in the aperture ratio, as shown in FIGS. 15 and 16, when one cell is configured to include a plurality of pixels in the scanning direction S (three cells in one cell in the scanning direction S in FIG. 15). There is a problem that the removed particles return to the region of the pixel scanned immediately before as the return particles 108, and the color of the back substrate cannot be displayed clearly.

As shown in FIG. 17, when a checkered pattern in which red pixels 106 and white pixels 110 are alternately arranged is displayed, the return particles are hidden by the white pixels 110, so the above problem does not occur. .
JP 2004-86095 A

  In order to solve the above problems, there is a method of scanning and driving the entire display area a plurality of times, but since the amount (number) of return particles is small, the driving effect is weak even if it is driven again and removed. The particles cannot be driven sufficiently. For this reason, there was a problem that particles could not be removed sufficiently.

  The present invention has been made in view of the above-described facts, and an object of the present invention is to provide an image display medium driving device that can sufficiently drive particles and prevent dot defects and the like.

  In order to solve the above-mentioned problem, the invention described in claim 1 is directed to a display substrate having at least translucency, a back substrate facing the display substrate with a gap, and a plurality of scans juxtaposed along a predetermined direction. Formed between the display substrate and the back substrate by applying a voltage according to image data between the electrodes and a plurality of data electrodes arranged to face each other so as to intersect the scanning electrodes A drive device for driving an image display medium comprising at least one kind of particle group sealed between the substrates so as to move in accordance with the applied electric field, and between the scan electrode and the data electrode A voltage applying means for applying a voltage to the electrode, and selecting at least two or more of the plurality of scan electrodes as a scan electrode group, scanning the selected scan electrode group a plurality of times, and then downstream of the scan direction To repeat the scanning sequence to a predetermined scanning electrode few minutes shift, characterized by comprising a control means for controlling said voltage applying means according to the image to be displayed.

  According to the present invention, the image display medium has a configuration in which at least one kind of particle group is sealed between a display substrate having at least translucency and a back substrate facing the display substrate with a gap. .

  In the particle group, a voltage corresponding to image data is applied between a plurality of scanning electrodes juxtaposed along a predetermined direction and a plurality of data electrodes arranged so as to cross the scanning electrodes. By this, it moves according to the electric field formed between the substrates.

  In such an image display medium, the color of the particles can be displayed by applying a voltage that moves the particles toward the display substrate between the scan electrode and the data electrode by the voltage applying means.

  The control means selects at least two or more of the plurality of scan electrodes as a scan electrode group, scans the selected scan electrode group a plurality of times, and then shifts by a predetermined number of scan electrodes downstream in the scan direction. The voltage application unit is controlled according to the image to be displayed so that the scanning sequence is repeated.

  That is, the same scanning electrode is repeatedly scanned a plurality of times, and the same scanning electrode is repeatedly shifted in the same manner by shifting the scanning electrode downstream by a predetermined number of scanning electrodes. Thereby, the hitting effect can be enhanced and the particles can be driven sufficiently, the display density deficiency can be improved, and dot-like display defects can be prevented.

  In addition, as described in claim 2, the particle group may have a configuration different from the color of the back substrate.

  In this case, when an electrode is provided on the surface of the back substrate facing the display substrate, this electrode may be transparent and the back substrate may have a color different from the color of the particles, or a colored layer may be provided on the electrode. Also good.

  In such an image display medium, the color of the back substrate is displayed by applying an alternating voltage between the scan electrode and the data electrode so that the particles move to the adjacent pixel region while reciprocating between the substrates. I can do it. In addition, about the application method of a voltage, the method described in Unexamined-Japanese-Patent No. 2004-86095 can be used, for example.

  According to a third aspect of the present invention, the particle group may be a plurality of types of particle groups having different colors and charging characteristics. As a result, the display color can be increased and the driveability of the particles due to the knock-out effect can be improved.

  According to a fourth aspect of the present invention, when the scanning electrode group is scanned a plurality of times, the control means starts the next scan before the movement of the particles that started moving by the previous scan is completed. Furthermore, it is preferable to control the voltage application means. Thereby, the hitting effect of the particles can be further increased, and dot defects and the like can be more effectively prevented.

  According to a fifth aspect of the present invention, the image display medium may further include a gap member that partitions the substrate into cells including a plurality of the scanning electrodes.

  In this case, as described in claim 6, the control means selects a scan electrode downstream of the gap member in the scanning direction and adjacent to the gap member as a scan start electrode in the scan electrode group. Also good. As a result, the pixels of the scanning start electrode can be clearly displayed when the color of the back substrate is displayed because the particles that attempt to return to the upstream side in the scanning direction are limited by the gap member.

  According to a seventh aspect of the present invention, the control means may select the scan electrode group so as to include at least all the scan electrodes in the cell.

  The control unit may select all the scan electrodes of at least one or more cells as a scan electrode group and scan the voltage for each of the at least one or more cells. You may make it control an application means. Thereby, it can scan efficiently.

  According to a ninth aspect of the present invention, the control means may select the next scan electrode group so as to include a part of the scan electrodes scanned last time. Thereby, a dot defect etc. can be prevented more effectively.

  According to the present invention, there is an effect that the particles can be driven sufficiently and dot defects and the like can be prevented.

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

  FIG. 1 shows a cross-sectional view of an image display medium 10 according to the present embodiment. As shown in the figure, the image display medium 10 is orthogonal to the scanning electrode 14 and a display substrate 18 in which a plurality of line-shaped transparent scanning electrodes 14 and a transparent insulating layer 16 are formed on a transparent substrate 12. A back-side substrate 28 having a line-shaped data electrode 20, a colored layer 22 and a transparent insulating layer 24 disposed on the substrate 26, and a positively charged black sealed between the substrates. It is composed of particles 30 and negatively charged white particles 32, and gap members 36 that partition the substrates into a plurality of cells 34 as shown in FIG.

  The colored layer 22 is a layer colored in a color different from the black particles 30 and the white particles 32, and is colored red in the present embodiment.

  The image display medium 10 shown in FIG. 1 is a cross-sectional view taken along the line AA in FIG. In FIG. 2, the gap member 36 is shown in black for the sake of clarity. However, the present invention is not limited to this, and a transparent member, for example, may be used.

  As shown in FIG. 2, the plurality of line-shaped scanning electrodes 14 are juxtaposed in the vertical direction (scanning direction S) in FIG. 2, and the plurality of line-shaped data electrodes 20 juxtaposed in the left-right direction in FIG. Are arranged so as to be orthogonal to each other. The intersection position of each scanning electrode 14 and each data electrode 20 constitutes a pixel. Each electrode is composed of, for example, an ITO (Indium Tin Oxide) electrode.

  The gap member 36 includes a plurality of scanning electrodes 14 and a plurality of data electrodes 20 and has a grid shape in which a plurality of substantially square cells 34 are formed. In FIG. 2, as an example, each cell 34 has a configuration in which three scanning electrodes 14 and three data electrodes 20 are arranged, that is, a configuration of 3 × 3 pixels per cell, but this is not a limitation. Absent.

  In FIGS. 1 and 2, for simplicity of explanation, the electrodes are arranged in a simple matrix structure of 6 rows × 6 columns, but in reality, the number of electrodes corresponding to the number of pixels necessary for image display is each substrate. Needless to say, it is formed. That is, if m rows × n columns of pixels are required, m scanning electrodes 14 are formed on the substrate 12, and n data electrodes 20 are formed on the substrate 26.

  In the present embodiment, the scanning electrode 14 is provided on the display substrate side and the data electrode 20 is provided on the rear substrate side. Conversely, the data electrode 20 is provided on the display substrate side. The scanning electrode 14 may be formed on the side.

  Further, the scanning electrode 14 and the data electrode 20 may be formed not on the surface on the side where the display substrate 18 and the back substrate 28 face each other but on the surface on the opposite side, respectively. It may be arranged separately and independently on the outside. When the electrodes are provided separately from the image display medium, an electric field can be formed between the substrates by configuring the substrates with a dielectric member.

  In this embodiment, the black particles 30 are positively charged and the white particles 32 are negatively charged. However, the black particles 30 are negatively charged and the white particles 32 are positively charged. Good. As each particle, for example, insulating particles, conductive particles, and the like can be used.

  As each member constituting the image display medium 10, for example, those described in Japanese Patent Laid-Open No. 2001-3225 can be used.

  In such an image display medium 10, the scanning electrode 14 has a predetermined voltage (for example, ± 140 V) that is a voltage necessary for generating a potential difference that can move at least particles between the substrates and that can secure a necessary concentration. And the data electrode 20, the black particles 30 and the white particles 32 at the positions move between the substrates. For example, when a predetermined voltage (for example, +140 V) at which the potential of the scanning electrode 14 is positive with respect to the data electrode 20 is applied between the electrodes, the positively charged black particles 30 on the display substrate 18 side are The negatively charged white particles 32 on the rear substrate 28 side move to the display substrate 18 side while moving to the 28 side, and are displayed in white.

  On the other hand, when a predetermined voltage (for example, −140 V) at which the potential of the scanning electrode 14 is negative with respect to the data electrode 20 is applied between the electrodes, the negatively charged white particles 32 on the display substrate 18 side are The positively charged black particles 30 moving to the substrate 28 side and moving to the rear substrate 28 side move to the display substrate 18 side and are displayed in black.

  Therefore, by applying a predetermined positive or negative voltage between the data electrode 20 and the scanning electrode 14 at a position corresponding to the pixel to which the particle is to be moved, the particle is moved according to the image and the image is displayed. Can do. Even after the voltage application is stopped, the black particles 30 or the white particles 32 remain attached to the display substrate 18 or the back substrate 28 by van der Waals force, mirror image force, or the like, and the image display is maintained.

  In the present embodiment, as an example, the case where the density characteristics of the image display medium 10 are characteristics as shown in FIGS. 3A and 3B will be described. That is, by setting the voltage applied to the scan electrode 14 to the data electrode 20 to −140 V or 140 V, the black particles 30 or the white particles 32 move to the display substrate 18 side and a sufficient density can be obtained. At the same time, when the voltage applied to the scanning electrode 14 with respect to the data electrode 20 is set to −70 V or 70 V, the particle movement can be prohibited. In the figure, the case where the pulse width of the applied voltage is 10 msec and the number of pulses is 1 is shown.

  Various values are set for the ON voltage and the OFF voltage for black display applied to the scanning electrode 14 and the data electrode 20, that is, the voltage value applied to each electrode when the black particles 30 are moved to the display substrate 18 side. In this embodiment, as shown in FIG. 4A, the first scan electrode ON voltage to be applied to the scan electrode 14 is set to -70 V, and the first data to be applied to the data electrode 20 is used. The electrode ON voltage is set to + 70V, and the OFF voltage applied to the scan electrode 14 and the data electrode 20 is set to 0V.

  Similarly, the ON voltage and the OFF voltage for white display applied to the scanning electrode 14 and the data electrode 20, that is, the value of the voltage applied to each electrode when moving the white particles 32 to the display substrate 18 side are various. In this embodiment, the second scan electrode ON voltage to be applied to the scan electrode 14 is applied to the data electrode 20 at +70 V having a polarity opposite to that of the first scan electrode ON voltage. The second data electrode ON voltage to be set is set to -70V having a polarity opposite to that of the first data electrode ON voltage, and the OFF voltage is set to 0V similar to the black display OFF voltage.

  When the ON voltage and the OFF voltage for black display are set as described above, when the ON voltage for black display is applied to both the scanning electrode 14 and the data electrode 20, as shown in FIG. The voltage applied to the scanning electrode 14 with respect to the data electrode 20 becomes −140 V, and the black particles 30 of the pixel (image portion) move to the display substrate 18 side.

  When the first scan electrode ON voltage is applied to the scan electrode 14 and the OFF voltage is applied to the data electrode 20, the applied voltage to the scan electrode 14 with respect to the data electrode 20 is -70V, and the pixel (non-image portion) is applied. ) Particles do not move. Similarly, when the OFF voltage is applied to the scan electrode 14 and the first data electrode ON voltage is applied to the data electrode 20, the applied voltage to the scan electrode 14 with respect to the data electrode 20 is -70V, and the particle of the pixel is When the OFF voltage is applied to the scanning electrode 14 and the OFF voltage is applied to the data electrode 20 without moving, the applied voltage to the scanning electrode 14 with respect to the data electrode 20 becomes 0 V, and the particles of the pixel do not move. The white display is the same as the black display only by reversing the polarity.

  Further, in the case of performing initialization driving in which the arrangement of the particles in the cell 34, that is, the particle density is made uniform and finally white display is performed, an initialization driving voltage is applied between the scanning electrode 14 and the data electrode 20. Apply the alternating voltage. For example, the first scan electrode initialization voltage is set to 140 V, the second scan electrode initialization voltage is set to 0 V, and these are alternately applied to the scan electrodes 14 with a predetermined pulse width. The initialization voltage for one data electrode is set to 0V, the initialization voltage for the second data electrode is set to 140V, and these are alternately applied to the data electrode 20 with the predetermined pulse width. As a result, an alternating voltage is applied between the scan electrode 14 and the data electrode 20.

  Then, this is executed for a predetermined number of pulses, and finally the first scan electrode initialization voltage is applied to the scan electrode 14 and the first data electrode initialization voltage is applied to the data electrode 20 in order to display white. To do. At this time, application with a pulse width longer than the predetermined pulse width is preferable because white display with more stable density can be performed. The predetermined number of pulses is set to a number that can sufficiently uniformize the arrangement of particles.

  Further, when displaying a color other than particles, that is, the color of the colored layer 22 for a predetermined pixel in the cell, a predetermined pulse as shown in FIG. 5A is applied to the scanning electrode 14 corresponding to the predetermined pixel. A pulse voltage for alternately applying the first scan electrode ON voltage and the second scan electrode ON voltage having a width is applied with a predetermined number of pulses (several pulses to several tens of pulses), and the data electrode corresponding to the predetermined pixel 20, a predetermined number of pulses of a pulse voltage for alternately applying the first data electrode ON voltage and the second data electrode ON voltage having the predetermined pulse width as shown in FIG. That is, pulse voltages having a phase difference of 180 degrees are applied to the scan electrode 14 and the data electrode 20. As a result, as shown in FIG. 5C, the scan electrode 14 has a voltage (−140 V) twice the first scan electrode ON voltage with respect to the data electrode 20 and the second scan electrode ON. An alternating voltage in which a voltage (+140 V) twice the voltage is applied alternately is applied. The frequency of the alternating voltage is 200 Hz as an example, and the predetermined number of pulses is 20 pulses as an example, but is not limited thereto. Hereinafter, the pulse voltage having a predetermined number of pulses shown in FIG. 5A is referred to as a scan electrode pulse voltage, and the pulse voltage having a predetermined number of pulses shown in FIG.

  Further, an OFF voltage is applied to the scanning electrode 14 and the data electrode 20 corresponding to pixels other than the predetermined pixel.

  As a result, the particles in a predetermined pixel region reciprocate between the substrates, while the edge electric field (electric field in a direction parallel to the substrate surface) formed between adjacent data electrodes moves to other pixel regions in the cell. The colored layer 22 is exposed to move, and red is displayed on the predetermined pixel.

  FIG. 6 shows a schematic configuration of the driving device 40 for displaying an image on the image display medium 10 based on the image data.

  The drive device 40 includes a scan electrode drive circuit 42, a data electrode drive circuit 44, power supply circuits 46 and 48, and a control device 50.

  The scan electrode driving circuit 42 is connected to each scan electrode 14 and is supplied with various voltages supplied from the power supply circuit 46, that is, the first scan electrode initialization voltage and the second scan electrode initialization voltage, and the first The scan electrode ON voltage, the second scan electrode ON voltage, the OFF voltage, and the like are applied to each scan electrode 14 in accordance with an instruction from the control device 50.

  The data electrode drive circuit 44 is connected to each data electrode 20 and is supplied with various voltages supplied from the power supply circuit 48, that is, a first data electrode initialization voltage and a second data electrode initialization voltage, The data electrode ON voltage, the second data electrode ON voltage, the OFF voltage, and the like are applied to each data electrode 20 in accordance with an instruction from the control device 50.

  The scan electrode drive circuit 42 is connected to each scan electrode 14 and applies various voltages supplied from the power supply circuit 46 to each scan electrode 14 in accordance with instructions from the control device 50.

  The data electrode drive circuit 44 is connected to each data electrode 20 and applies various voltages supplied from the power supply circuit 48 to each data electrode 20 in accordance with instructions from the control device 50.

  Image data corresponding to an image to be displayed on the image display medium 10 is input to the control device 50. Based on the input image data, the control device 50 scans a row number designation signal for designating the row number of the scan electrode 14 to be scanned and a scan electrode voltage designation signal for designating the type of applied voltage. A column number designation for designating the column number of the data electrode 20 to which a predetermined voltage is to be applied based on the line image corresponding to the scanning electrode 14 designated by the row number designation signal while being output to the electrode drive circuit 42 A data electrode voltage specifying signal for specifying the signal and the type of the predetermined voltage is output to the data electrode driving circuit 44.

  The scan electrode drive circuit 42 applies a voltage of the type designated by the scan electrode voltage designation signal to the scan electrode 14 of the row designated by the row electrode designation signal from the control device 50, and the row number designation signal. An OFF voltage is applied to the scan electrodes 14 other than the scan electrode 14 designated by the above.

  The data electrode drive circuit 44 applies a voltage of the type specified by the data electrode voltage specification signal to the data electrode 20 of the column specified by the control device 50 by the column number specification signal, and also supplies a column number specification signal. An OFF voltage is applied to the data electrodes 20 other than the data electrode 20 designated by the above.

  Next, a voltage application sequence for image display driving executed by the control device 50 will be described.

  First, the control device 50 initializes the image display medium 10. That is, in order to make the particles uniform and to display the entire surface white, all the scanning electrodes 14 and the data electrodes 20 are applied with pulse voltages having a predetermined number of pulses that are 180 degrees out of phase, and finally, the scanning electrodes 14. The first scan electrode initialization voltage instructs the scan electrode drive circuit 42 and the data electrode drive circuit 44 to apply the first data electrode initialization voltage to the data electrode 20. As a result, the particles between the substrates are made uniform, and finally, all the white particles 32 move to the display substrate 18 side, and all the black particles 30 move to the back substrate 28 side, so that the entire surface is displayed in white.

  Next, the control device 50 receives a row number designation signal for designating the first scan electrode 14 and a scan electrode voltage designation signal for designating the first scan electrode ON voltage for black display. A column number designation signal for designating the data electrode 20 corresponding to the pixel to be displayed in black on the first row and the ON voltage for the first data electrode for black display are designated as well as being output to the scan electrode drive circuit 42. For this purpose, a data electrode voltage designation signal is output to the data electrode drive circuit 44.

  As a result, the first scanning electrode ON voltage is applied to the scanning electrode 14 in the first row, and the first data electrode ON voltage is applied to the data electrode 20 corresponding to the pixel to be displayed black in the first row. Pixels are displayed in black, and a black and white line image of that row is displayed. Further, an OFF voltage is applied to the other electrodes. Hereinafter, this is referred to as black display driving. Note that the number of pulses of the applied voltage in the black display driving may be one pulse or several pulses.

  Then, the black display drive similar to the above is performed for the second row, but the black display drive is not performed for the third row, but the black display drive similar to the above is performed again in the order of the first row and the second row. I do. That is, the first and second rows are scanned twice.

  Particles that move easily when voltage is applied start to move, and almost all particles start moving due to the knock-out effect, and move to the desired substrate side according to the formed electric field. Since the electric field strength between the substrates is weakened by this, the moving speed of the particles and the knocking-out effect are weakened, and a certain amount of time (for example, several tens of milliseconds) is required until all the particles are completely moved. In the present embodiment, in order to increase the hit particles, the second scan is started before the particles that have started moving by the first scan complete the movement. That is, one scanning time (voltage application time) is set to a time (for example, several msec) shorter than the time from the start of voltage application to the complete movement of all particles.

  After scanning the first row and the second row twice, the second row scanned last time is set as the scanning target instead of the third row in the order of the second row and the third row. Repeat the black display drive twice. Hereinafter, the black display drive is repeated twice in the order of the third row and the fourth row, and the black display drive is repeated twice in the order of the fourth row and the fifth row, and so on.

  Thus, in this embodiment, two adjacent scan electrodes 14 are selected as a scan electrode group, and the selected scan electrode group is scanned twice. Further, the scan electrode group is shifted downstream in the scanning direction so that the scan electrode scanned last in the scan electrode group scanned last time becomes the scan electrode of the next scan electrode group. Note that the number of scans of one scan electrode group is not limited to two, but may be three or more.

  In FIG. 7, the concept of such a scanning method is indicated by an arrow. In the figure, the scan electrode from the start point to the end point of the arrow written on one data electrode 20 corresponds to the scan electrode group, and the plurality of arrows indicate that the scan electrode group is scanned a plurality of times. That is, in FIG. 7, the scan electrodes for two rows are selected as the scan electrode group, and after scanning the selected scan electrode group a plurality of times (for example, twice), the scan electrode group for one row is moved downstream in the scanning direction. To shift.

  By scanning as described above, the voltage application time for one scan electrode is short, so the time until the selected scan electrode group is scanned once and then scanned again is short. A second scan is started before the particles that have started moving have completely moved. Particles that have not completed their movement can move easily when a voltage is applied again, and thus act as knockout particles. Therefore, the number of knocked-out particles can be increased. As a result, display density deficiency is improved and dot-like display defects can be prevented.

  Next, the controller 50 designates a row number designation signal for designating the scan electrode 14 in the first row and a scan electrode voltage designation signal for designating a scan electrode pulse voltage as shown in FIG. Is output to the scan electrode drive circuit 42, the column number designation signal for designating the data electrode 20 corresponding to the pixel to be displayed in red on the first row, and the data electrode pulse voltage as shown in FIG. Is output to the data electrode driving circuit 44.

  Thereby, an alternating voltage for particle removal as shown in FIG. 5C is applied between the data electrode 20 corresponding to the pixel to be displayed in red and the scanning electrode 14. Further, an OFF voltage is applied to the other electrodes.

  As a result, particles between the data electrode 20 corresponding to the pixel to be displayed in red and the scanning electrode 14 move to the other pixel region, that is, the pixel region for white display or black display while reciprocating between the substrates. . For this reason, when the colored layer 22 is exposed, red is displayed. Hereinafter, this is referred to as red display driving.

  Then, the red display drive similar to the above is performed for the second row, but the red display drive for the third row is not performed next, but the red display drive similar to the above is performed again in the order of the first row and the second row. I do. That is, similarly to the black display driving, the first and second rows are scanned twice. Thereafter, similarly to the black display driving, the red display driving is performed in a sequence as shown in FIG.

  By scanning in this way, the knocked-out particles can always be sufficiently present so that the particles can be moved reliably, preventing dot-like display defects and improving the particle removal rate. be able to.

  The combination of the number of voltage pulses applied to the electrodes and the number of scans of the scan electrode group depends on the conditions such as the number of scan electrodes selected as the scan electrode group, the size of the particles, the resolution, the distance between the substrates, Select according to the characteristics of the device. For example, a combination of the number of pulses and the number of scans can be appropriately selected, such as 1 pulse × 40 times, 2 pulses × 20 times, 10 pulses × 4 times, 20 pulses × 2 times, and the like. For example, when the particle diameter is small or the resolution is coarse, the number of particles to be moved increases, so a combination with a large number of pulses is selected. However, it is necessary to make a combination so that the next scan is started before the particles that have started moving by the previous scan are completely moved.

  The present inventors applied an alternating voltage frequency of 1 kHz applied during red display driving using an image display medium having a particle diameter of 8 to 10 μm, a distance between substrates of 80 to 100 μm, and a resolution of 80 to 240 dpi. When an experiment was conducted at a voltage of 140 V, it was found that conditions of 2 to 5 pulses and 8 to 4 scans were preferable.

  In addition, the upper limit value of the number of scan electrodes in the scan electrode group is determined by the time when the driving of the particles is completed, and this also varies depending on the conditions of the device. For example, when the movement of the particles is almost completed in 20 to 30 msec after starting the driving of the particles, it is preferable to set the scanning again within 20 msec.

  Specifically, for example, when four scanning electrodes are selected as the scanning electrode group, the number of pulses is preferably set to 5 or less (4 × 5 pulses = 20 msec) when the frequency of the alternating voltage is 1 kHz. That is, 5 pulses are applied to one scanning electrode. As a result, the next scanning can be performed before the movement of the particles is completed, and the knocked-out particles can be increased.

  Next, another example of the scanning method will be described.

  In the above, the two scanning electrodes 14 are selected as the scanning electrode group, the selected scanning electrode group is scanned twice, and the scanning electrode group is repeatedly shifted downstream in the scanning direction by one line. However, for example, as indicated by the solid arrows in FIG. 8, the two scanning electrodes 14 are selected as the scanning electrode group, the selected scanning electrode group is scanned a plurality of times, and the scanning electrode group is divided into two lines, In other words, it may be possible to repeat shifting to the downstream side in the scanning direction by the number of scanning electrodes included in the scanning electrode group.

  Further, as indicated by the dotted arrows in the figure, all the scanning electrodes 14 in the cell are selected as a scanning electrode group and scanned a plurality of times, and the number of scanning electrodes 14 in the cell (for three lines) is downstream in the scanning direction. You may make it repeat shifting to the side. Thereby, it can scan efficiently.

  Further, as indicated by the one-dot chain line arrow in the figure, all the scanning electrodes 14 for two cells are selected as a scanning electrode group and scanned a plurality of times, and the number of scanning electrodes 14 for two cells (for six lines). ) May be repeated repeatedly in the scanning direction. Thereby, it is possible to scan more efficiently.

  Further, as indicated by solid line arrows in FIG. 9, all of the scanning electrodes 14 in the cell 34 and one of the scanning electrodes 14 of the cell 34 on the downstream side in the scanning direction of the cell 34 are selected as a scanning electrode group, and a plurality of times. The scanning may be repeated so that the number of scanning electrodes 14 in the cell 34 (for three lines) is shifted downstream in the scanning direction.

  Further, as indicated by the dotted arrows in the figure, all the scanning electrodes 14 in the cell 34, one cell 34 upstream of the cell 34 in the scanning direction, and one scanning electrode 14 of the cell 34 downstream in the scanning direction, respectively. May be selected as a scan electrode group, and a plurality of scans may be performed, and the number of scan electrodes 14 in the cell 34 (for three lines) may be repeatedly shifted downstream in the scan direction.

  In addition, as indicated by the one-dot chain line arrow in the figure, all the scanning electrodes 14 for two cells, the cell 34 on the upstream side in the scanning direction of the cell 34 and the scanning electrode 14 on the downstream side in the scanning direction are connected. Each of them may be selected as a scanning electrode group and scanned a plurality of times, and the number of scanning electrodes 14 corresponding to two cells (for 6 lines) may be repeatedly shifted downstream in the scanning direction. May be selected as a scan electrode group, and a plurality of scans may be performed, and the shift by the number of scan electrodes 14 for two cells (for 6 lines) may be repeated.

  In the scanning method indicated by the solid line, dotted line, and alternate long and short dash line in FIG. 8 and the scanning method indicated by the solid line in FIG. 9, the scanning electrode 14 at the start of scanning is adjacent to the gap member 36 on the upstream side in the scanning direction. For this reason, the return of the particles can be limited by the gap member 36, and the red display can be displayed more clearly.

  In the case of the scanning method indicated by the dotted line and the alternate long and short dash line in FIG. 8 and the scanning method in FIG. 9 (particularly, the scanning method indicated by the solid line), if attention is paid to the inside of the cell, the pixels in the cell are driven to display almost simultaneously. Therefore, when driving red display, if the particle tries to return to the pixel area upstream in the scanning direction, it cannot be returned by starting the next scan, and the particle is removed. It is surely moved to the site to be. Therefore, it is possible to suppress a reduction in the removal rate due to the return particles, and it is possible to display clearly even when red display pixels continue in the scanning direction.

  In addition, the gap member 36 is preferably provided between the scan electrodes as shown in FIGS. For example, as shown in FIG. 10, when the gap member 104 is arranged on the scan electrode 100, when the red display pixel 106 continues along the scanning direction S as shown in FIG. 11, the pixel on the upstream side of the gap member 104. The particles 108 remain and the image quality deteriorates, but this can be prevented by arranging the gap member between the scanning electrodes.

  In this embodiment, the case of repeatedly scanning a plurality of times for each of black and white display and red display has been described. However, only one of the displays may be repeatedly scanned a plurality of times.

  Further, in the above description, the entire white display is performed and then the black display is performed for each row and then the red display is performed. However, the black display may be performed after the red display.

It is sectional drawing of an image display medium. It is a top view which shows arrangement | positioning of an electrode and the shape of a gap | interval member. (A) is a diagram showing density characteristics when displaying from black to white, and (B) is a diagram showing density characteristics when displaying from black to white. (A) is a figure for demonstrating the ON voltage and OFF voltage applied to each electrode, (B) is for demonstrating the voltage applied to each position when ON voltage or OFF voltage is applied to each electrode. FIG. It is a wave form diagram of the voltage applied in the case of removal drive (red display drive). It is a schematic block diagram of an image display apparatus. It is a figure for demonstrating a scanning sequence. It is a figure for demonstrating the other example of a scanning sequence. It is a figure for demonstrating the other example of a scanning sequence. It is a top view which shows arrangement | positioning of an electrode in case a gap | interval member exists on a scanning electrode, and the shape of a gap | interval member. It is a figure for demonstrating the return particle which generate | occur | produces when a gap | interval member exists on a scanning electrode. It is a top view which shows arrangement | positioning of the electrode in the past, and the shape of a gap | interval member. It is a figure which shows the example of a display at the time of displaying the image in which red display continues in a scanning direction in the conventional image display medium. It is a figure which shows the example of a display at the time of displaying the image in which red display continues in a scanning direction in the conventional image display medium. It is a figure which shows the example of a display when a return particle | grain generate | occur | produces when displaying the image with which red display continues in a scanning direction in the conventional image display medium. It is a figure which shows the example of a display when a return particle | grain generate | occur | produces when displaying the image with which red display continues in a scanning direction in the conventional image display medium. It is a figure which shows the example of a display at the time of displaying a checkerboard pattern in the conventional image display medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image display medium 12 Substrate 14 Scan electrode 16 Insulating layer 18 Display substrate 20 Data electrode 22 Colored layer 24 Insulating layer 26 Substrate 28 Back substrate 30 Black particle 32 White particle 34 Cell 36 Gap member 40 Drive device 42 Scan electrode drive circuit 44 Data Electrode drive circuit 46 Power supply circuit 48 Power supply circuit 50 Control device

Claims (9)

A display substrate having at least translucency, a rear substrate facing the display substrate with a gap, a plurality of scanning electrodes juxtaposed along a predetermined direction, and facing the scanning electrode. A voltage corresponding to image data is applied between the plurality of data electrodes, so that the display electrode moves between the substrates so as to move according to an electric field formed between the display substrate and the back substrate. A drive device for driving an image display medium comprising at least one kind of encapsulated particle group,
Voltage application means for applying a voltage between the scan electrode and the data electrode;
A scanning sequence in which at least two or more scanning electrodes among the plurality of scanning electrodes are selected as a scanning electrode group, and the selected scanning electrode group is scanned a plurality of times and then shifted downstream by a predetermined number of scanning electrodes in the scanning direction. The control means for controlling the voltage application means according to the image to be displayed,
An apparatus for driving an image display medium, comprising:   The image display medium driving device according to claim 1, wherein the particle group has a color different from that of the back substrate.   3. The image display medium driving device according to claim 1, wherein the particle group is a plurality of types of particle groups having different colors and charging characteristics.   The control means controls the voltage application means so that the next scan is started before the movement of the particles started to move by the previous scan is performed when the scan electrode group is scanned a plurality of times. 3. The image display medium driving device according to claim 1, wherein the image display medium is driven by the driving device.   5. The image display medium according to claim 1, further comprising a gap member that divides the substrate into cells including a plurality of the scanning electrodes. 6. Drive device.   6. The drive of an image display medium according to claim 5, wherein the control means selects a scan electrode downstream of the gap member in the scanning direction and adjacent to the gap member as a scan start electrode in the scan electrode group. apparatus.   7. The image display medium driving device according to claim 5, wherein the control unit selects the scan electrode group so as to include at least all the scan electrodes in the cell.   The control means selects all the scan electrodes of at least one or more cells as a scan electrode group, and controls the voltage application means to scan for each of the at least one or more cells. The drive device for an image display medium according to any one of claims 5 to 7.   8. The control unit according to claim 1, wherein the control unit selects a next scan electrode group so as to include a part of scan electrodes of the scan electrode group scanned last time. Drive device for image display medium.

Images