JP2010113154A - Method of driving information display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of driving an information display device, which can reduce unevenness of contrast due to cross talk. <P>SOLUTION: In the driving method of the information display device in which information of an image or the like is displayed by moving a display medium having a first color and a display medium having a second color which are sealed between two substrates, when an image of one screen is displayed by applying voltage by scanning from one end of a row electrode to the other end for a row electrode group consisting of a plurality of electrodes arranged in the row direction on one substrate and a column electrode group consisting of a plurality of electrodes arranged in the column direction on the other substrate, after display of one screen is finished, voltage causing cross talk in a first color display pixel or voltage causing cross talk in a second color display pixel is applied one time or more respectively for all pixels of one screen. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  According to the present invention, a display medium having a first color and a display medium having a second color are sealed between two opposing substrates, at least one of which is transparent, and the two types of display media are moved to form an image. The present invention relates to a driving method of an information display device that displays information such as.

  As an information display device that replaces liquid crystal (LCD), an electrophoretic information display device in which charged particles are used as a display medium and the display medium is driven in a liquid, and charged particles are used as a display medium, and the display medium is used in a gas. An information display device that is driven is proposed.

  Compared with LCD, the information display device has a wide viewing angle close to that of a normal printed matter, and has a memory property that continues to display the information image once displayed even when the power is turned off. In recent years, it is expected to be used as an electronic paper as an information display device that can rewrite displayed information many times because of low power consumption.

  In addition, an information display device using a charged particle as a display medium and driving the display medium in a gas has a driving threshold value, and thus has a complicated circuit configuration using a switching element (for example, a thin film transistor: TFT). Even without active matrix drive, the information image to be displayed is displayed in dot matrix by simple matrix drive (passive matrix drive), or the information image to be displayed is displayed in segments by simple segment drive (passive dynamic drive). Therefore, the expectation as cheap electronic paper is also increasing.

As an information display device applicable to the electronic paper, at least one of them is sealed between substrates with electrodes facing each other, and the display medium is moved by an electric field formed by a voltage applied between the electrodes to An information display device that displays information is known.
Pamphlet of International Publication WO2003 / 050606

  In the information display device for displaying information such as an image by enclosing a display medium between substrates with electrodes facing at least one of the transparent electrodes, and moving the display medium with an electric field formed by a voltage applied between the electrodes. A row electrode group consisting of a plurality of electrodes arranged in the row direction on the substrate side of the substrate, and a column electrode group consisting of a plurality of electrodes arranged in the column direction on the other substrate side, from one end of the row electrode to the other When displaying information on one screen by scanning the edge and applying a voltage, there is a problem that crosstalk described below occurs when driving to display a matrix or when driving a segment dynamically. .

  Crosstalk is a phenomenon in which signals from other lines are originally mixed in the telephone, but in this case, crosstalk is actually affected by other rows even though the column electrode is not selected. This is a phenomenon in which different information is displayed. In the display by the passive matrix drive of the information display device using the above-described display medium, a voltage for holding the display is applied to the non-selected row of the column electrode. Due to the effect that the holding voltage is applied by the number of rows of the column electrodes, the display of information such as an image is shaded and uneven.

  FIG. 10 is a diagram for explaining shading unevenness caused by crosstalk in a conventional information display device. In the example shown in FIG. 10, for the sake of simplicity, information such as an 8 × 6 image composed of the lower row electrodes 11-1 to 11-6 and the upper column electrodes 12-1 to 12-8 is shown. . The electrode pairs formed by the row electrodes and the column electrodes are filled with white and black display media having different charging characteristics, and the row electrodes 11-1 to 11-6 and the column electrodes 12-1 to 12-8 are filled. Black and white display is performed according to the voltage applied between the two. The driving method is a full screen batch erasing method, and the row electrodes 11-1 to 11-6 are scanned in that order to display information such as images. During scanning, all the screens of the row electrodes 11-1 to 51-6 are erased by applying a voltage of 0V, while the non-selected rows are subjected to a voltage of 0V when erasing all the screens at a time. This is done by applying 50V. At the same time, the column electrodes 12-1 to 12-8 apply a voltage of 100 V to the write column and apply a voltage of 0 to the columns other than the write column when erasing the entire screen.

  The example shown in FIG. 10 shows an example in which scanning is started from the row electrode 11-1 and writing is ended in the last row electrode 11-6. In FIG. 10, among the first row electrode 11-1, the second row electrode 11-2, and the third row electrode 11-3, the portion A, which should originally be white, is whitish due to crosstalk. The portion B, which is displayed in gray and should be displayed in black, is displayed in blackish gray due to crosstalk, and the display of information such as an image is shaded and uneven.

  An object of the present invention is to provide a method for driving an information display apparatus that can eliminate the above-described problems and reduce unevenness in density caused by crosstalk.

  The information display device driving method of the present invention encloses a display medium having a first color and a display medium having a second color between two opposing substrates, at least one of which is transparent, In a driving method of an information display device that displays information such as an image by moving a display medium, a row electrode group including a plurality of electrodes arranged in a row direction on one substrate, and a column direction on the other substrate When displaying a one-screen image by applying a voltage by scanning from one end of the row electrode to the other end of a column electrode group consisting of a plurality of electrodes arranged in the A voltage that generates crosstalk in the first color display pixel or a voltage that generates crosstalk in the second color display pixel is applied to all the pixels of one screen at least once each.

  As a preferred example of the driving method of the information display device of the present invention, as the simplest method for realizing the above, one or more lines are added at the end of the scan, and after the first scan is completed, the display of the first color or Driving to display the second color display one or more times, applying a voltage that generates crosstalk of a color different from the color used when erasing information prior to information display, and information prior to information display The erasing method may be a divided erasing method in which information is written for each row after the entire surface is divided into a plurality of erases, or an all erasing method in which information is written for each row after erasing the entire surface all at once. .

  According to the driving method of the information display device of the present invention, after the display of one screen is finished, the voltage for generating the crosstalk in the first color display pixel or the voltage for generating the crosstalk in the second color display pixel is set. Apply one or more times to all pixels of one screen, preferably, add one or more rows at the end of the scan, and after one scan is finished, display the first color or the second color by 1 By displaying more than once, for example, in the case of black and white display, white can be displayed in a slightly black and light gray or black can be displayed in a slightly white and dark gray, resulting in crosstalk in displaying information such as images. The shading unevenness can be reduced.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  First, a basic configuration of an information display panel included in an information display device that is an object of the present invention will be described. In the information display panel used in the information display device of the present invention, an electric field is applied to a display medium configured as a group of particles containing chargeable particles sealed between two opposing substrates. Along with the applied electric field direction, the display medium is attracted by an electric field force or a Coulomb force, and the display medium is moved by a change in the electric field direction, whereby information such as an image is displayed. Therefore, it is necessary to design the information display panel so that the display medium can move uniformly and maintain stability when rewriting the display repeatedly or when displaying the display information continuously. Here, as the force applied to the particles constituting the display medium, in addition to the force attracting each other by the Coulomb force between the particles, an electric mirror image force between the electrode and the substrate, an intermolecular force, a liquid cross-linking force, gravity and the like can be considered.

  An example of an information display panel used in the information display device of the present invention will be described with reference to FIGS. 1 (a), 1 (b), 2 (a), and 2 (b).

  In the example shown in FIGS. 1 (a) and 1 (b), at least two types of display media having different optical reflectivity and charging characteristics (here, configured as a particle group including particles having at least optical reflectivity and chargeability) The white display medium 3W configured as a particle group including the negatively charged white particles 3Wa and the black display medium 3B configured as a particle group including the positively charged black particles 3Ba are shown). In the cell, a voltage is applied to pixel electrode pairs arranged in a matrix formed by the line electrodes 6 as row electrodes provided on the substrate 2 and the line electrodes 5 as column electrodes provided on the substrate 1 formed to cross each other at right angles. Is moved perpendicularly to the substrates 1 and 2 in accordance with the electric field generated by. Then, the white display medium 3W is visually recognized by the observer as shown in FIG. 1A, or the black display medium 3B is visually recognized by the observer as shown in FIG. 1B. Are displayed in a matrix with black and white dots. In addition, in FIG. 1 (a), (b), the partition in front is abbreviate | omitted.

  In the example shown in FIGS. 2A and 2B, at least two types of display media having different optical reflectance and charging characteristics (here, configured as a particle group including particles having at least optical reflectance and charging properties (here) 3 shows a white display medium 3W configured as a particle group including negatively charged white particles 3Wa and a black display medium 3B configured as a particle group including positively charged black particles 3Ba). In the cell, a voltage is applied to a segment electrode pair formed by an electrode 5 (segment electrode) as a row electrode provided on the substrate 1 and an electrode 6 (segment electrode) as a column electrode provided on the substrate 2 facing each other. Is moved perpendicularly to the substrates 1 and 2 in accordance with the electric field generated by. Then, the white display medium 3W is visually recognized by the observer as shown in FIG. 2A, or the white display is displayed by the observer, or the black display medium 3B is visually recognized by the observer as shown in FIG. 2B. In black and white segment shape. In addition, in FIG. 2 (a), (b), the partition in front is abbreviate | omitted.

  The driving method of the information display device of the present invention is characterized by a row electrode group consisting of a plurality of electrodes arranged in the row direction on one substrate side and a plurality of electrodes arranged in the column direction on the other substrate side. To display a one-screen image by applying a voltage by scanning from one end of the row electrode to the other end of the column electrode group, crosstalk into the first color after the display of one screen is completed. Or a voltage for generating crosstalk in the second color (crosstalk voltage 2) is applied to all pixels of one screen at least once each. Here, the crosstalk voltage 1 and the crosstalk voltage 2 are, for example, an example in which a voltage of 100 V and a voltage of −100 V are applied to display white as the first color and black as the second color. The voltage 50V is applied as 1 or the voltage −50V is applied as the crosstalk voltage 2. Specifically, one or more lines are added at the end of the scan, and after one scan is completed, the drive for displaying the first color display or the second color display at least once is performed, and the information Applying a voltage that generates crosstalk in a color different from the color used when erasing information prior to display, and erasing information prior to displaying information by dividing the entire surface into multiple parts and then deleting each line There is a divided erasing method in which information is written in the memory, or an all erasing method in which information is written for each row after erasing the entire surface at once.

  3 (a) to 3 (c) to 6 (a) to 6 (c) are diagrams for explaining an example in which the driving method of the present invention is added to the conventional example shown in FIG. In the examples shown in FIGS. 3A to 3C to 6A to 6C, the row electrodes 11-1 to 11-6 and the column electrodes 12-1 to 12-1 are used as in the conventional example shown in FIG. In addition to providing 12-8, a row electrode 11-7 is additionally provided as the last row in advance.

In the example of “white erasure → virtual row black writing” shown in FIGS. 3A to 3C, after the scanning of the image display portion is completed (FIG. 3B), here, the row electrode 11-6 is used. Until the image of one screen of 8 × 6 pixels is displayed, black writing is performed on the row electrode 11-7, which is the last row, as shown in FIG.
As a result, as shown in FIG. 3 (c), white is unified to light gray, black is unified to black and dark gray, and does not become 100% white or black, respectively. Since all are displayed in light gray, shading unevenness caused by crosstalk can be reduced.

In the example of “white erasure → virtual row white writing” shown in FIGS. 4A to 4C, after scanning of the image display portion is finished (FIG. 4B), here, the row electrode 11-6 is used. Until a single screen image of 8 × 6 pixels is displayed, white writing is performed on the row electrode 11-7 which is the last row as shown in FIG. 4C (actually 12− 1 to 8 are non-write voltages).
As a result, as shown in FIG. 4 (c), white is unified into white and light gray, and black is unified into dark gray. Since dark gray is displayed, shading unevenness caused by crosstalk can be reduced.

In the example of “black erasure → virtual row white writing” shown in FIGS. 5A to 5C, after the scanning of the image display portion is finished (FIG. 5B), here, the row electrode 11-6 is used. Until the image of one screen of 8 × 6 pixels is displayed, white writing is performed on the row electrode 11-7, which is the last row, as shown in FIG.
As a result, as shown in FIG. 5 (c), white is unified into white and light gray, and black is unified into dark gray. Since dark gray is displayed, shading unevenness caused by crosstalk can be reduced.

In the example of “black erasure → virtual row black writing” shown in FIGS. 6A to 6C, after the scanning of the image display portion is completed (FIG. 6B), here, the row electrode 11-6 is used. Until a single screen image of 8 × 6 pixels is displayed, black writing is performed on the row electrode 11-7, which is the last row, as shown in FIG. 6C (actually 12− 1 to 8 are non-write voltages).
As a result, as shown in FIG. 6 (c), white is unified to light gray, black is unified to black and dark gray, and it does not become 100% white or black respectively, but all parts that are desired to be displayed in white are all Since it is displayed in light gray, it is possible to reduce shading unevenness caused by crosstalk.

  In the examples shown in FIGS. 3A to 3C to 6A to 6C, the entire erasing method for erasing the entire surface and then writing for each line has been described as an example. In the line erasing method written from the beginning, the shading unevenness can be similarly reduced. Furthermore, in the example shown in FIGS. 3A to 3C to 6A to 6C, the display medium is filled up to the added row electrode 11-7 to actually perform monochrome display. However, this portion is not filled with a display medium, and after the image display of one screen of 8 × 6 is finished, a white color is provided between the newly provided row electrode 11-7 and the extended portion of each column electrode. By applying a voltage for performing display or a voltage for performing black display, shading unevenness can be similarly reduced.

In the driving method of the information display device of the present invention, on the premise that crosstalk occurs, the first color (for example, white) or the second color is selected as the color of the pixel that becomes gray due to the generated crosstalk. In combination with (for example, black), the first feature is light gray, or the second color is dark gray. At that time, the first color (for example, white) and the second color (for example, black) are combined with the color of the pixel that has become gray due to the generated crosstalk, and the first color is made light gray. Compared with the case where the second color is dark gray (in the case of Japanese Patent Laid-Open No. 2005-331904), the crosstalk reduction effect is reduced, but the power consumption can be reduced and the code length of the program can be halved. There are advantages.
In addition, when displaying information such as an image, a voltage for forming an image is applied after applying a voltage for erasing the image. In particular, in an information display device having display memory properties, the voltage applied finally In order to maintain the state changed by the above, the shading unevenness caused by the crosstalk due to the voltage applied to display the color forming the image (that is, the color different from the color used when erasing the image) In consideration of the fact that the ratio that affects the image quality degradation is larger than the density unevenness caused by crosstalk due to the voltage applied to erase the image, the color selected in the driving method of the information display device of the present invention described above is By selecting a color different from the color used for erasing the image from among the first color and the second color, it is possible to more effectively reduce the density unevenness.

  Next, an example in which the driving method of the information display device of the present invention is actually applied will be described. 7, 8 (a), 8 (b), 9 (a), and 9 (b) are diagrams for explaining the effects of the driving method of the information display device of the present invention. First, in this example, the image shown in FIG. 7 is displayed. FIG. 8A shows an example in which an image is displayed by a conventional driving method in line erasing, and an example in which an image is displayed by the driving method of the present invention in which white or black is written in the last line in the line erasing. Is shown in FIG. FIG. 9A shows an example in which an image is displayed by the conventional driving method in all erasing, and an example in which an image is displayed by the driving method of the present invention in which white or black is written in the last line in the same erasing. Is shown in FIG. Comparing FIG. 8A and FIG. 8B, and FIG. 9A and FIG. 9B, in the line erasing method and the total erasing method, there is no shading unevenness due to crosstalk in the conventional example. On the other hand, in the example of the present invention, it can be seen that shading unevenness due to crosstalk is reduced.

  In the above-described example, the voltage value to be applied when erasing or writing the pixel is not mentioned, but the shade of the image varies greatly depending on the voltage value (Volt) depending on the structure of the information display device. Generally, when the voltage value (Volt) is low, black display cannot be performed. On the other hand, when the voltage value is high, there is no difference between the gray portion and the black portion due to crosstalk. Therefore, it is necessary to select an optimum voltage according to the structure of the information display device, and a voltage of about 80V to 110V is used as an example.

  Hereinafter, each member which comprises the information display apparatus used as the object of this invention is demonstrated.

  As for the substrate, at least one substrate is the transparent substrate 2 from which the color of the display medium can be confirmed from the outside of the information display panel, and a material having high visible light transmittance and good heat resistance is preferable. The substrate 1 may be transparent or opaque. Examples of substrate materials include polymer sheets such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and glass and quartz. An inorganic sheet having no flexibility is mentioned. The thickness of the substrate is preferably 2 to 2000 μm, more preferably 5 to 1000 μm. If it is too thin, it will be difficult to maintain the strength and the uniformity of the distance between the substrates, and if it is thicker than 2000 μm, it will be a thin information display panel. Is inconvenient.

  Examples of electrode forming materials include metals such as aluminum, silver, nickel, copper, and gold, indium tin oxide (ITO), indium zinc oxide (IZO), indium oxide, aluminum-doped zinc oxide (AZO), conductive tin oxide, Examples include conductive metal oxides such as antimony tin oxide (ATO) and conductive zinc oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene. As a method for forming the electrode, a method of forming the above-described materials into a thin film by sputtering, vacuum vapor deposition, CVD (chemical vapor deposition), coating, or the like, or a method of laminating metal foil (for example, rolled copper foil) Etc.), and a method in which a conductive agent is mixed with a solvent or a synthetic resin binder and applied. The electrode provided on the display surface side substrate 2 which is on the viewing side and needs to be transparent needs to be transparent, but the electrode provided on the back side substrate 1 does not need to be transparent. In any case, the above-mentioned material that can be patterned and is electrically conductive can be suitably used. The electrode thickness may be 0.01 to 10 [mu] m, preferably 0.05 to 5 [mu] m, as long as electrical conductivity can be ensured and light transmittance is not hindered. The material and thickness of the electrode provided on the back side substrate 1 are the same as those of the electrode provided on the display surface side substrate described above, but need not be transparent.

The shape of the partition 4 in the case where the partition is provided on the substrate is appropriately set appropriately depending on the type of display medium involved in display, the shape and arrangement of the electrodes to be arranged, and is not limited in general. The height of the partition is adjusted to 100 to 100 μm, preferably 3 to 50 μm, and the height of the partition wall to 10 to 100 μm, preferably 10 to 50 μm. The height of the partition provided for securing the inter-substrate gap is 10 to 500 μm. If the height of the partition becomes the inter-substrate gap, and the partition for cell formation is formed within the range of 10 to 500 μm, the partition is low. It is good.
In forming the partition wall, a both-rib method in which ribs are formed on each of the opposing substrates 1 and 2 and then bonded, and a single-rib method in which ribs are formed only on one substrate are conceivable. In the present invention, any method is preferably used.
The cells formed by the partition walls made of these ribs are exemplified by a square shape, a triangular shape, a line shape, a circular shape, and a hexagonal shape when viewed from the substrate plane direction, and the arrangement is exemplified by a lattice shape, a honeycomb shape, or a mesh shape. The It is better to make the portion corresponding to the cross section of the partition wall visible from the display surface side (the area of the cell frame) as small as possible, and the clearness of the display increases.
Here, examples of the method for forming the partition include a mold transfer method, a screen printing method, a sand blast method, a photolithography method, and an additive method. Any of these methods can be suitably used for the information display panel of the present invention, and among these, a photolithography method using a resist film and a mold transfer method are suitably used.

  The information display device that is the subject of the present invention includes notebook computers, electronic notebooks, portable information devices called PDA (Personal Digital Assistants), display units of mobile devices such as mobile phones and handy terminals, electronic books, electronic newspapers Electronic paper, signboards, posters, bulletin boards such as blackboards (whiteboards), electronic desk calculators, home appliances, automotive supplies, card displays such as point cards, IC cards, electronic advertisements, information boards, electronic POP ( Point Of Presence, Point Of Purchase advertising), electronic price tag, electronic shelf label, electronic score, RF-ID equipment display, as well as various POS terminals, car navigation devices, watches, etc. In addition, it can be suitably used as a display unit (rewritable paper) that is connected to an external rewriting unit to perform display rewriting.

(A), (b) is a figure which shows an example of the information display panel used with the information display apparatus of this invention, respectively. (A), (b) is a figure which shows the other example of the information display panel used with the information display apparatus of this invention, respectively. (A)-(c) is a figure for demonstrating the example which added the drive system of the information display apparatus of this invention with respect to the prior art example shown in FIG. (A)-(c) is a figure for demonstrating the other example which added the drive system of the information display apparatus of this invention with respect to the prior art example shown in FIG. (A)-(c) is a figure for demonstrating the other example which added the driving method of the information display apparatus of this invention with respect to the prior art example shown in FIG. (A)-(c) is a figure for demonstrating the other example which added the driving method of the information display apparatus of this invention with respect to the prior art example shown in FIG. It is a figure for demonstrating the effect of the drive method of the information display apparatus of this invention. (A), (b) is a figure for demonstrating the effect of the drive method of the information display apparatus of this invention, respectively. (A), (b) is a figure for demonstrating the effect of the drive method of the information display apparatus of this invention, respectively. It is a figure for demonstrating the shading nonuniformity resulting from the crosstalk in the conventional information display apparatus.

Explanation of symbols

1, 2 Substrate 3W White display medium 3Wa Negatively charged white particle 3B Black display medium 3Ba Positively charged black particle 4 Partition 5 Row electrode (or column electrode)
6 column electrodes (or row electrodes)
11-1 to 11-8 row electrode 12-1 to 12-8 column electrode

Claims (4)

A display medium having a first color and a display medium having a second color are encapsulated between two opposing substrates at least one of which is transparent, and information such as images is transferred by moving the two types of display media. In the driving method of the information display device to display,
A row electrode group consisting of a plurality of electrodes arranged in the row direction on one substrate and a column electrode group consisting of a plurality of electrodes arranged in the column direction on the other substrate from one end of the row electrode When displaying the image of one screen by scanning and applying a voltage to the other end, the voltage or the second color display pixel that causes crosstalk in the first color display pixel after the display of one screen is finished. A method for driving an information display device, wherein a voltage for generating crosstalk is applied to all pixels of one screen at least once each.   2. The display device according to claim 1, wherein one or more lines are added at the end of the scan, and after the one scan is completed, the display of the first color display or the second color display is performed once or more. Driving method of the information display apparatus.   3. The method of driving an information display device according to claim 1, wherein a voltage for generating crosstalk of a color different from a color used for erasing information prior to information display is applied.   The erasing method of information prior to displaying information is divided erasing method that divides the entire surface into multiple parts and then writes the information for each row, or all erasing method that erases the entire surface and then writes the information for each row. The method for driving an information display device according to claim 1, wherein the information display device is driven.

Images