JP2008287172A - Panel for information display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a panel for information display capable of preventing the deterioration of image quality due to the degradation of voltage caused by the difference of applied voltage in the counter electrode of a line-shaped electrode by changing an inter-substrate distance in accordance with the positional relation between the power source connection terminal of the line-shape electrode formed of a transparent conductive material having a higher electric resistance as compared with metal. <P>SOLUTION: The panel for information display is configured so as to move a display medium and display information such as an image by applying an electric field from the counter electrode formed while making the line-shaped electrodes 5, 6 formed on two sheets of substrates intersect a display medium (charged particles) filled in a space between the substrates 1, 2, wherein the inter-substrate distance is continuously changed such that, as the position is farther from the power source connection terminal of the line-shaped transparent electrode, the inter-substrate distance corresponding to the position becomes narrower. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a display medium made of display particles having optical reflectivity and chargeability is sealed in a space between two substrates, at least one of which is transparent, and display is performed from line electrodes provided on the two substrates, respectively. The present invention relates to an information display panel that displays information such as images by moving a display medium by applying an electric field to the medium.

  Conventionally, as a dot matrix type information display device that replaces a liquid crystal display (LCD), a method of moving particles in gas (electron powder fluid method), a method of moving particles in liquid (electrophoresis method), an electrochromic method An information display device using a technique such as a thermal method or a two-color particle rotation method has been proposed.

  Compared to LCDs, these conventional technologies have advantages such as a wide viewing angle close to that of ordinary printed materials, low power consumption, and a memory function. It is considered as a technology that can be used for mobile phones, and is expected to expand to information display for mobile terminals, electronic paper, and the like.

  Among the various next-generation information display devices described above, a display medium made of display particles having optical reflectivity and chargeability is sealed in a space between two substrates, at least one of which is transparent, and the two substrates The information display panel that displays information such as images by moving the display medium by applying an electric field to the display medium from the electrodes provided on each of the electrodes is superior in display memory characteristics (bistable characteristics). Can be used as a dot matrix type passive matrix type information display panel composed of line-shaped electrodes that cross each other at right angles to each other, and is expected to be cheaper than an active matrix type information display panel (for example, Patent Documents) 1).

JP 2006-58643 A

  The counter electrode used in the dot matrix type passive matrix drive system is arranged so that the line electrodes are opposed and orthogonal to each other, but since it is a line electrode, it is applied between the counter electrodes on the power connection end side of the line electrode. A difference caused by a voltage drop is generated between the applied voltage and the voltage applied between the counter electrodes on the front end side of the line electrode. As a result, a difference occurs in the electric field acting between the counter electrodes, which affects the drivability of particles as a display medium. That is, there arises a problem that the image quality (for example, contrast) displayed becomes non-uniform due to the difference in driveability of the display medium in the display area of the information display panel. It should be noted that such a decrease in image quality due to a decrease in voltage becomes a problem with a display screen size in which the length of the line electrode is long (for example, a display screen size of B5 or more).

  In the present invention, the difference in the applied voltage at the counter electrode of the line electrode is changed by changing the distance between the substrates according to the positional relationship between the power connection end of the line electrode and the counter electrode used in the dot matrix type passive matrix driving method. An object of the present invention is to provide an information display panel that prevents image quality deterioration caused by voltage drop caused by the above.

  In order to achieve the above object, an information display panel of the present invention encloses a display medium made of display particles having optical reflectivity and chargeability in a space between two substrates, at least one of which is transparent. An information display panel for displaying information such as an image by moving the display medium by applying an electric field to the display medium from a counter electrode formed by a line electrode provided on each of the substrates, The inter-substrate distance is continuously changed so that the inter-substrate distance corresponding to the position becomes narrower the farther from the power source connection end of the line-shaped transparent electrode among the electrodes. .

  A preferred example of the information display panel according to the present invention is an information display panel of a charged particle driving system, and the driving method of the display medium is that an electric field is applied between counter electrodes formed by crossing opposing line-shaped electrodes. The information display panel is a dot matrix type passive drive system, and the space between the two substrates of the information display panel is a gas space.

  According to the information display panel of the present invention, a display medium made of display particles having optical reflectivity and chargeability is sealed in a space between two substrates, at least one of which is transparent, and the two substrates are enclosed. In an information display panel that displays information such as an image by moving the display medium by applying an electric field to the display medium from a counter electrode formed by each provided line-shaped electrode, at least the line-shaped electrode among the line-shaped electrodes Since the distance between the substrates is continuously changed so that the distance from the power source connection end of the transparent electrode becomes narrower, the distance between the substrates corresponding to the position becomes narrower. Therefore, it is possible to provide an information display panel with improved image quality.

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

  First, the configuration of the information display panel of the present invention will be described. In this information display panel, an electric field is applied to at least two types of display media (charged particles) sealed in a space between two opposing substrates. Along with the applied electric field direction, the charged display medium is attracted by the force of the electric field or the Coulomb force, and the display medium is moved by the 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 the stability when the display information is rewritten or when the display information is continuously displayed. 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 that is an object of the present invention will be described with reference to FIGS. 1A, 1B, 2A, 2B, 3, and 4. FIG.

  In the example shown in FIGS. 1A and 1B, at least two types of display media 3 (here, the display white particles 3Wa) having different optical reflectance and charging characteristics composed of at least one type of particles are used. The electrode 5 (line electrode) provided on the substrate 1 in each cell formed by the partition walls 4, in which the white display medium 3 </ b> W including the particle group and the black display medium 3 </ b> B including the display black particle 3 </ b> Ba are illustrated. And an electrode 6 (line electrode) provided on the substrate 2 are moved perpendicularly to the substrates 1 and 2 in accordance with an electric field generated by applying a voltage. Dot matrix display is performed by pixels (dots) formed by overlapping the opposing line-shaped electrodes. Then, as shown in FIG. 1 (a), the white display medium 3W is visually recognized by the observer to display white dots on a black background, or the black display medium 3B is visually recognized by the observer as shown in FIG. 1 (b). Or black dots on a white background. In addition, in FIG. 1 (a), (b), the partition in front is abbreviate | omitted. Here, a partition is provided corresponding to a pixel (dot) formed by overlapping line-shaped electrodes facing each other, but this partition may not correspond to a pixel or a partition may not be provided.

  In the example shown in FIGS. 2A and 2B, an example of color display in which a display unit (one dot) is configured by three cells (pixels) is shown. In the example shown in FIGS. 2A and 2B, as the display medium, the white display medium 3W and the black display medium 3B are enclosed in all of the cells 21-1 to 21-3, and the first cell 21-1 is included. A red color filter 22R is provided on the viewer side, a green color filter 22G is provided on the viewer side of the second cell 21-2, a blue color filter 22B is provided on the viewer side of the third cell 21-3, A display unit (one dot) is composed of three cells, the first cell 21-1, the second cell 21-2, and the third cell 21-3. Dot matrix color display is performed by pixels (dots) formed by three pixels formed by overlapping line electrodes facing each other. In this example, when performing color display, as shown in FIG. 2A, the white display medium 3W is moved to the observer side in all of the first cell 21-1 to the third cell 21-3. Thus, white dots are displayed to the observer, and as shown in FIG. 2B, the black display medium 3B is placed on the observer side in all of the first cell 21-1 to the third cell 21-3. By moving, black dots are displayed to the observer. Multicolor color dot display can be performed by moving the display medium of each cell. In addition, in FIG. 2 (a), (b), the partition in front is abbreviate | omitted. Here, all the partition walls are provided corresponding to the pixel pixels (pixels) formed by overlapping the line electrodes facing each other. However, if the partition walls are provided corresponding to the pixels (dots), the partition walls corresponding to the pixels are provided. It does not have to be.

  In the example shown in FIG. 3, the example of the color display which comprises a display unit (1 dot) with the three cells (pixel) is shown. In the example shown in FIG. 3, as the display medium, a white display medium 3W and a red display medium 3R are enclosed in a cell (pixel) 21-1, and a white display medium 3W and a blue display medium 3BL are enclosed in a cell (pixel) 21-2. The white display medium 3W and the green display medium 3G are sealed in the cell (pixel) 21-3, and the first cell (pixel) 21-1, the second cell (pixel) 21-2, and the second The three cells (pixels) of the three cells (pixels) 21-3 constitute a display unit (pixel; 1 dot). Dot matrix color display is performed by pixels (dots) formed by three pixels formed by overlapping line electrodes facing each other. In this example, when performing color display, in the pixel 21-1 formed by the partition 4, the electrode 5 (line electrode) provided on the substrate 1 and the electrode 6 (line electrode) provided on the substrate 2 are arranged. The red display medium 3R is moved to the observer side in accordance with the electric field generated by applying a voltage therebetween, and the electrodes 5 provided on the substrate 1 in the pixels 21-2 and 21-3 formed by the partition walls 4. The white display medium 3W is moved to the viewer side according to the electric field generated by applying a voltage between the (line electrode) and the electrode 6 (line electrode) provided on the substrate 2, and from 3 pixels. Red dots are displayed in one pixel (one dot). Multi-color dot display can be performed by moving the display medium of each pixel. In FIG. 3, the front partition is omitted.

  In the example shown in FIG. 4, a microcapsule 9 in which a white display medium 3 </ b> W and a black display medium 3 </ b> B are enclosed as a display medium (charged particles) together with an insulating liquid 8 is enclosed in a space between the substrates 1 and 2. The counter electrodes are constituted by the shaped electrodes 5 and 6. In this example, the display medium is moved in accordance with the electric field generated by applying a voltage between the electrode 5 provided on the substrate 1 and the electrode 6 provided on the substrate 2, thereby overlapping the line electrodes facing each other. And the microcapsule arrangement position are combined, the size of the microcapsule becomes a pixel (dot), and dot matrix display is performed for the observer. Although FIG. 4 shows an example in which no partition is provided, a configuration in which a partition is provided between microcapsules may be used. Also in this case, an inter-substrate distance securing member for keeping the inter-substrate distance constant is disposed.

Hereinafter, an arrangement example of the information display panel of the present invention will be described in detail with reference to the drawings.
5A to 5C are views showing an outline of the information display panel of the present invention. The information display panel of the present invention is an information display panel of a charged particle driving method, and the driving method of the display medium (charged particles) is to apply an electric field to the counter electrode at the intersection of the line-shaped electrodes that are orthogonal to each other. This is a dot matrix type information display panel adopting a passive matrix system.
In the information display panel of the present invention, a display medium made of display particles having optical reflectivity and chargeability is enclosed in a space between the back side substrate 1 and the display side transparent substrate 2, and the substrates 1 and 2 are enclosed. An information display panel that displays information such as an image by moving the display medium by applying an electric field to the display medium from a counter electrode formed by intersecting line electrodes 5 and 6 provided later, which will be described later. In this manner, the inter-substrate distance is continuously changed so that the farther the position from the power source connection end of the line electrode 5 is, the narrower the inter-substrate distance corresponding to the position is.

The information display panel of the present invention has the state shown in FIG. 5C by bonding the display surface side transparent substrate 2 shown in FIG. 5A and the back surface side substrate 1 shown in FIG. 5B. Configure. In the display surface side transparent substrate 2 shown in FIG. 5A, a plurality of display surface side line electrodes 6 arranged so as to extend in the horizontal direction in the figure, and the display surface side line electrodes 6 are illustrated. A leader line 10 coupled to the right end is disposed. The lead wire 10 is provided with a metal material having good conductivity. Hereinafter, the connection end of the display surface side line electrode 6 and the lead wire 10 is referred to as a connection side end, and the end farthest from the power connection end of the display surface side line electrode 6 is the non-connection side end. I will call it.
The back side substrate 1 shown in FIG. 5B is coupled to a plurality of back side line electrodes 5 arranged so as to extend in the vertical direction in the drawing and the lower end portions of the back side line electrodes 5 shown in the drawing. The leader line 11 is arranged. The lead wire 11 shall be provided with a metal material having good conductivity. In the following, the connection end of the back line electrode 5 and the lead wire 11 is referred to as a connection end, and the end farthest from the power connection end of the back line electrode 5 is referred to as an anti-connection end. To.
The information display panel of the present invention, as shown in FIG. 5C showing a state viewed from the display surface side substrate 2 side, a power connection member 12 electrically connected to all the leader lines 10, Each line-like electrode is connected to a power source (not shown) using a power connection member 13 such as a flexible circuit board (FCP) that is electrically connected to all the lead wires 11. An area indicated by an inner broken line in FIG. 5C (an area where the line-shaped electrodes 5 and 6 are provided) is an information display area. In this information display area, a plurality of cells (small rooms) containing two-color display media are arranged between the substrates so that dot matrix display is possible, and line electrodes formed on the two substrates are arranged orthogonally. The display medium is driven by a matrix-like counter electrode formed in this manner.

Next, an arrangement example of the information display panel of the present invention will be described.
The arrangement example 1 of the information display panel of the present invention shown in FIGS. 6A to 6C includes two sets when the back side line electrode and the display side line electrode are both line ITO transparent electrodes. The distance between the substrates in the length direction of the line-like ITO electrode was controlled so as to be continuously changed. As shown in FIG. 6B, which is an AA cross-sectional view of FIG. 6A, and FIG. 6C, which is a BB cross-sectional view of FIG. 6A, the height of the partition wall is continuously increased. By changing the distance, the display surface side substrate 2 was inclined with respect to the upper surface of the back side substrate 1 to control the inter-substrate distance. In this case, the area circled at the lower right in FIG. 6A is the maximum inter-substrate distance area, and the area circled at the upper left in FIG. 6A is the inter-substrate distance minimum area. 6B and 6C, the inter-substrate distance securing member 14 is disposed on the outer peripheral portion of the panel located outside the information display area. In FIGS. 6A to 6C, the entry of the display medium to be enclosed in the cell between the substrates is omitted. Here, the partition walls are provided corresponding to all the pixels (dots). However, the partition wall is provided only on the outermost peripheral portion of the panel, or the partition wall is provided only on the outermost peripheral portion of the panel and a part of the panel. Good. The partition shape, partition arrangement, and pixels (dots) may or may not correspond to each other. The pixel shape is a square, the partition shape (cell shape), and the partition arrangement is a hexagonal honeycomb. You can also.

In this arrangement example 1, since the line-like ITO electrode 5 is also provided on the back-side substrate 1 among the line-like electrodes arranged opposite to each other, the line direction of the line-like ITO electrode having a larger electric resistance than the metal electrode. A continuous change (distance difference) was applied to the distance between the substrates. This continuous change (distance difference) between the substrates is achieved by continuously changing the height of the partition provided for forming cells between the substrates and / or the inter-substrate distance securing member 14 provided on the outermost periphery. Form. That is, as shown in FIGS. 6B and 6C, the height of the partition provided at the position corresponding to the power connection end of the line-like ITO electrode provided on both substrates is increased to correspond to the tip of the line electrode. The height of the partition wall provided at the position to be lowered was reduced, and the partition wall was continuously changed in a range in which the height difference was 2 to 10 μm. The range of the difference between the distances between the two substrates depends on the length of the line-shaped transparent electrode made of a material having a higher electric resistance than that of metal such as ITO, but the position corresponding to the power connection end of the line-shaped transparent electrode The inter-substrate distance at the position corresponding to the tip of the line-shaped transparent electrode is set to be narrower in the range of 2 to 10 μm than the inter-substrate distance in FIG.
By reducing the distance between the substrates, the electric field strength applied to the display medium is maintained even when the voltage applied to the counter electrode is small. Therefore, the electric field with the same intensity is applied to all the display media arranged in the display area. And the occurrence of variations in the drivability of the display medium can be suppressed. As a result, the entire screen can be displayed with uniform image quality.

  In the arrangement example 2 of the information display panel of the present invention shown in FIGS. 7A to 7C, the back-side line-shaped electrode is a line-shaped copper electrode, and the display-surface-side line-shaped transparent electrode is a line-shaped ITO electrode. In this case, the distance between the substrates in the length direction of the line-like ITO electrode is controlled to be continuously changed. As shown in FIG. 7B, which is a CC cross-sectional view of FIG. 7A, by continuously changing the height of the partition wall, the display surface side substrate 2 with respect to the upper surface of the back side substrate 1 is obtained. The substrate distance was controlled by controlling the distance between the substrates. In this case, the region surrounded by the ellipse at the left end in FIG. 7A is the minimum inter-substrate distance region, and the region surrounded by the ellipse at the right end in FIG. 7A is the maximum inter-substrate distance region. In FIG. 7B, an inter-substrate distance securing member 14 is disposed on the outer periphery of the panel located outside the information display area. In this arrangement example 2, since the back-side line-shaped electrode is a line-shaped copper electrode, the voltage applied between the counter electrode on the power supply connecting end side of the line-shaped electrode and the counter electrode on the tip side of the line-shaped electrode are applied. In view of the fact that a difference due to a voltage drop is less likely to occur with respect to the applied voltage, as shown in FIG. 7C, the height of the partition provided on the back substrate 1 is not changed. The leader line 11 of the back side substrate 1 can be provided with the same metal material as the line copper electrode 5 which is a back side line electrode. In FIGS. 7A to 7C, a display medium enclosed in a cell between substrates is omitted. Here, the partition walls are provided corresponding to all the pixels (dots). However, the partition wall is provided only on the outermost peripheral portion of the panel, or the partition wall is provided only on the outermost peripheral portion of the panel and a part of the panel. Good. The partition shape, partition arrangement, and pixels (dots) may or may not correspond to each other. The pixel shape is a square, the partition shape (cell shape), and the partition arrangement is a hexagonal honeycomb. You can also.

In this arrangement example 2, since the line-shaped ITO electrode 6 is provided on the display surface side transparent substrate 2 among the line-shaped electrodes arranged to face each other, the line direction of the line-shaped ITO electrode having a large electric resistance compared to metal. A continuous change (distance difference) was applied to the distance between the substrates. This continuous change (distance difference) between the substrates is formed by continuously changing the height of the partition provided for forming the cells between the substrates. That is, as shown in FIG. 7B, the height of the partition provided at the position corresponding to the power connection end of the line-shaped transparent electrode is increased, and the height of the partition provided at the position corresponding to the tip of the line-shaped transparent electrode. The partition wall was continuously changed so that the difference in height was 2 to 10 μm. The range of the difference between the distances between the two substrates depends on the length of the line-shaped transparent electrode made of a material having a higher electric resistance than that of metal such as ITO, but the position corresponding to the power connection end of the line-shaped transparent electrode The inter-substrate distance at the position corresponding to the tip of the line-shaped transparent electrode is set to be narrower in the range of 2 to 10 μm than the inter-substrate distance in FIG. Although it depends on the length of the line-shaped transparent electrode made of ITO material, the distance between the substrates at the position corresponding to the tip of the line-shaped transparent electrode is larger than the distance between the substrates at the position corresponding to the power connection end of the line-shaped transparent electrode. The distance is set to be narrower in the range of 2 to 10 μm.
By reducing the distance between the substrates, the electric field strength applied to the display medium is maintained even when the voltage applied to the counter electrode is small. Therefore, the electric field with the same intensity is applied to all the display media arranged in the display area. And the occurrence of variations in the drivability of the display medium can be suppressed. As a result, the entire screen can be displayed with uniform image quality.

  Hereinafter, each member and other components constituting the information display panel of the present invention will be described.

  As the substrate, at least one substrate is a transparent substrate on which the color of the display medium can be confirmed from the outside of the panel, and a material having high visible light transmittance and good heat resistance is preferable. The back substrate as the other substrate may be transparent or opaque. Examples of substrate materials include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene (PE), polycarbonate (PC), polyimide (PI), polyethersulfine (PES), acrylic polymer substrates Alternatively, a glass sheet, a quartz sheet, a metal sheet, or the like is used, and a transparent one is used on the display surface side. 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.

Among the line electrodes disposed on the substrate facing each other, transparent electrode materials include indium tin oxide (ITO), indium oxide, zinc-doped indium oxide (IZO), antimony tin oxide (ATO), conductive tin oxide, Examples thereof include transparent conductive metal oxides such as conductive zinc oxide and transparent conductive polymers such as polyaniline, polypyrrole, and polythiophene, which are provided on a transparent substrate disposed on the display surface side. Of course, these transparent electrodes can be provided on the back substrate.
The electrode material provided on the back side substrate that does not need to be transparent among the line-shaped electrodes arranged opposite to each other includes copper, silver, gold, aluminum, nickel, neodymium, and alloys containing them as main components (for example, Nd- Examples thereof include metals having good conductivity such as Cr).
As a method for forming an electrode, a method of forming the above-described materials into a thin film by sputtering, vacuum deposition, CVD (chemical vapor deposition), coating, or the like, or mixing a conductive agent with a solvent or a synthetic resin binder. In addition to the coating method, a method of laminating a metal foil (for example, a rolled copper foil) is used. The above-mentioned material that can be patterned and is electrically conductive can be preferably used.
The thickness of the electrode provided on the display surface side substrate may be 3 to 1000 nm, preferably 5 to 400 nm, as long as conductivity is ensured and light transmittance is not hindered. Further, the thickness of the electrode provided on the back side substrate may not be transparent as long as the conductivity can be ensured, and is preferably 3 to 1000 nm, preferably 5 to 400 nm. The material and thickness of the electrode provided on the back side substrate are the same as those of the electrode provided on the display surface side substrate described above, but need not be transparent. In an information display panel having both substrates as transparent substrates and both line electrodes as transparent line electrodes, double-sided display using both front and back surfaces is possible.

The shape of the partition provided on the substrate is appropriately set according to the type of display medium involved in display, the shape and arrangement of the electrodes to be arranged, and is not generally limited. However, the width of the partition is 2 to 100 μm, preferably 3 The height of the partition wall is adjusted to 10 to 100 μm, preferably 10 to 50 μm. In the present invention, the height of the partition wall is continuously changed.
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 this invention, any method can be used, but the single rib method in which the height can be easily adjusted is preferable.
As shown in FIG. 8, 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 as viewed from the substrate plane direction. And a mesh shape. 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 display becomes clearer.
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 an information display panel mounted on the information display device of the present invention, and among these, a photolithography method using a resist film and a mold transfer method are suitably used.

A method of charging particles (display particles) constituting the display medium to be negative or positive is not particularly limited, and a method of charging particles such as a corona discharge method, an electrode injection method, and a friction method is used. It is preferable that the charge amount of particles measured by a blow-off method using a carrier is 10 to 100 μC / g in absolute value. When the absolute value of the charge amount is lower than this range, the response speed with respect to the change in the electric field is slowed, and the memory property is also lowered. If the absolute value of the charge amount is higher than this range, the image force on the electrode or the substrate is too strong, and the memory property is good, but the reversal followability of the display medium when the electric field is reversed becomes poor.
In the present invention, the charge amount was measured as follows.
<Blow-off measurement principle and measurement method>
In the blow-off method, a mixture of display particles and carrier particles is placed in a cylindrical container with nets at both ends, and high-pressure gas is blown from one end to separate the display particles and carrier particles from the mesh openings. Only the display particles are blown off. At this time, the charge amount equivalent to the charge amount that the display particles have been taken out of the container remains in the carrier particles. All of the electric flux due to this charge is collected by the Faraday cage, and the capacitor is charged by this amount. Therefore, by measuring the potential across the capacitor, the charge amount Q of the display particles is
Q = CV (C: capacitor capacity, V: voltage across the capacitor)
As required.
As a blow-off charge amount measuring device, TB-200 manufactured by Toshiba Chemical Corporation was used. In the present invention, a ferrite carrier is used to measure the charge amount of the particles to be measured. The information display panel is composed of, for example, a display medium composed of positively chargeable display particles and negatively chargeable display particles. When two types of display media such as a display medium are used in combination, the same type of carrier particles is used when measuring the charge amount of the display particles constituting each display medium. Specifically, the charge amount (μC / g) of the display particles was measured using DFC100 wrinkle (Mn—Mg-containing ferrite system) manufactured by Dowa Iron Powder Industry Co., Ltd. as carrier particles.

Since the particles need to retain their charged charges, insulating particles having a volume resistivity of 1 × 10 ¹⁰ Ω · cm or more are preferable, and in particular, insulating particles having a volume resistivity of 1 × 10 ¹² Ω · cm or more. Is preferred. Further, particles having a slow charge decay property are more preferable.

Next, display particles (hereinafter also referred to as particles) constituting the display medium in the information display panel that is the subject of the present invention will be described. The display particles are used as they are as a display medium by being composed of the display particles alone, combined with other particles to be a display medium, or microcapsules are used as a display medium.
The display particles may contain a charge control agent, a colorant, an inorganic additive, and the like, if necessary, in the resin as the main component, as in the conventional case. Examples of resins, charge control agents, colorants, and other additives will be given below.

  Examples of the resin include urethane resin, urea resin, acrylic resin, polyester resin, acrylic urethane resin, acrylic urethane silicone resin, acrylic urethane fluororesin, acrylic fluororesin, silicone resin, acrylic silicone resin, epoxy resin, polystyrene resin, styrene Acrylic resin, polyolefin resin, butyral resin, vinylidene chloride resin, melamine resin, phenol resin, fluororesin, polycarbonate resin, polysulfone resin, polyether resin, polyamide resin and the like can be mentioned, and two or more kinds can be mixed. In addition, a resin polymerized in advance may be used, or a resin may be polymerized at the time of particle formation. Furthermore, it is good also as a copolymer using several types of resin raw materials at the time of superposition | polymerization. In particular, an acrylic resin, an acrylic fluororesin, a polystyrene resin, and a styrene acrylic resin are suitable from the viewpoint of controlling the adhesive force with the substrate and the ease of suspension polymerization.

  The charge control agent is not particularly limited. Examples of the negative charge control agent include salicylic acid metal complexes, metal-containing azo dyes, metal-containing oil-soluble dyes (including metal ions and metal atoms), and quaternary ammonium salt systems. Examples thereof include compounds, calixarene compounds, boron-containing compounds (benzyl acid boron complexes), nitroimidazole derivatives, and styrene acrylic resins having negatively charged functional groups. Examples of the positive charge control agent include nigrosine dyes, triphenylmethane compounds, quaternary ammonium salt compounds, polyamine resins, imidazole derivatives, and styrene acrylic resins having positively charged functional groups. In addition, metal oxides such as ultrafine silica, ultrafine titanium oxide, ultrafine alumina, nitrogen-containing cyclic compounds such as pyridine and derivatives and salts thereof, various organic pigments, resins containing fluorine, chlorine, nitrogen, etc. are also charged. It can also be used as a control agent.

  As the colorant, various organic or inorganic pigments and dyes as exemplified below can be used.

Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon and the like.
Examples of blue colorants include C.I. I. Pigment blue 15: 3, C.I. I. Pigment Blue 15, Bituminous Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Metal-free Phthalocyanine Blue, Phthalocyanine Blue Partial Chlorides, Fast Sky Blue, Indanthrene Blue BC, and the like.
Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, resol red, pyrazolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment Red 2 etc.

Yellow colorants include chrome yellow, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment Yellow 12 etc.
Examples of green colorants include chrome green, chromium oxide, pigment green B, C.I. I. Pigment Green 7, Malachite Green Lake, Final Yellow Green G, etc.
Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment Orange 31 etc.
Examples of purple colorants include manganese purple, first violet B, and methyl violet lake.
Examples of white colorants include zinc white, titanium oxide, antimony white, and zinc sulfide.

  Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white. Examples of various dyes such as basic, acidic, disperse, and direct dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

Examples of inorganic additives include titanium oxide, zinc white, zinc sulfide, antimony oxide, calcium carbonate, lead white, talc, silica, calcium silicate, alumina white, cadmium yellow, cadmium red, cadmium orange, titanium yellow, Examples include bitumen, ultramarine blue, cobalt blue, cobalt green, cobalt violet, iron oxide, carbon black, manganese ferrite black, cobalt ferrite black, copper powder, and aluminum powder.
These pigments and inorganic additives can be used alone or in combination. Of these, carbon black is particularly preferable as the black pigment, and titanium oxide is preferable as the white pigment. By blending the colorant, display particles having a desired color can be produced.

  The display particles of the present invention (hereinafter also referred to as particles) preferably have an average particle diameter d (0.5) in the range of 1 to 20 μm and are uniform and uniform. If the average particle diameter d (0.5) is larger than this range, the display is not clear. If the average particle diameter d (0.5) is smaller than this range, the cohesive force between the particles becomes too large, which hinders movement as a display medium.

Furthermore, in the present invention, regarding the particle size distribution of each display particle, the particle size distribution Span represented by the following formula is less than 5, preferably less than 3.
Span = (d (0.9) −d (0.1)) / d (0.5)
(However, d (0.5) is a numerical value expressing the particle diameter in μm that 50% of the particles are larger than this and 50% is smaller than this, and d (0.1) is a particle in which the ratio of the smaller particles is 10%. (Numerical value expressed in μm, and d (0.9) is a numerical value expressed in μm for a particle diameter of 90% or less.)
By keeping Span within a range of 5 or less, the size of each particle is uniform, and movement as a uniform display medium becomes possible.

  Furthermore, regarding the correlation between the display particles, the ratio of d (0.5) of the particles having the minimum diameter to d (0.5) of the particles having the maximum diameter among the used particles is 50 or less, preferably 10 or less. It is important. Even if the particle size distribution Span is reduced, particles with different charging characteristics move in opposite directions, so that the particle size is close to each other and each particle can be easily moved in the opposite direction by the equivalent amount. This is within this range.

The particle size distribution and the particle size can be obtained from a laser diffraction / scattering method or the like. When laser light is irradiated onto particles to be measured, a light intensity distribution pattern of diffracted / scattered light is spatially generated, and this light intensity pattern has a corresponding relationship with the particle diameter, so that the particle diameter and particle diameter distribution can be measured. .
Here, the particle size and particle size distribution in the present invention are obtained from a volume-based distribution. Specifically, using a Mastersizer2000 (Malvern Instruments Ltd.) measuring instrument, particles are introduced into a nitrogen stream, and the attached analysis software (software based on volume-based distribution using Mie theory) The diameter and particle size distribution can be measured.

Furthermore, when producing an information display panel that drives a display medium (charged particles) that is the subject of the present invention in a gas space, it is important to manage the gas in the void surrounding the display medium between the substrates, Contributes to improved display stability. Specifically, it is important that the relative humidity at 25 ° C. is 60% RH or less, and preferably 50% RH or less for the humidity of the gas in the gap.
This gap portion refers to the electrodes 5 and 6 from the portion sandwiched between the opposing substrate 1 and substrate 2 in FIGS. 1 (a), 1 (b), 2 (a), 2 (b), 3 and 4, respectively. (When an electrode is provided inside the substrate), an occupied portion of the display medium 3, an occupied portion of the partition wall 4 (when a partition wall is provided), and a gas portion in contact with a so-called display medium excluding a seal portion of the information display panel Shall point to.
The gas in the gap is not limited as long as it is in the humidity region described above, but dry air, dry nitrogen, dry argon, dry helium, dry carbon dioxide, dry methane, and the like are preferable. This gas needs to be sealed in an information display panel so that the humidity is maintained, for example, filling a display medium, assembling an information display panel, etc. in a predetermined humidity environment, It is important to apply a sealing material and a sealing method that prevent moisture from entering from the outside.

  The volume occupation ratio of the display medium composed of particles in the cell space in the gas between the opposing substrates is preferably 5 to 70%, more preferably 5 to 60%. When it exceeds 70%, the movement as a display medium is hindered, and when it is less than 5%, the contrast tends to be unclear.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples of the present invention, but the present invention is not limited to the following.

<Example 1>
An information display panel was manufactured by the following process.
(1) Partition wall (rib) and electrode pattern forming process on substrate (2) Display medium filling process on substrate (3) Unnecessary display medium removal process on partition wall (4) Adhesive layer formation on partition wall Process (5) Bonding process of two substrates

[Formation of electrode pattern]
An ITO film (thickness: 200 nm) of 30Ω / □ is formed on the surface of the display screen area (250 mm × 250 mm) of the glass substrate 1 and the glass substrate 2 having a thickness of 200 μm by a photoresist method, and a pattern of line ITO electrodes Formed.
Thereafter, the partition wall forming material formed on the substrate 1 on which the line-shaped ITO electrode is formed is subjected to CMP (Chemical Chemical Process) so that the length of the line-shaped ITO electrode has an inclination gradient with a maximum thickness of 40 μm and a minimum thickness of 35 μm. (Mechanical polishing) and then photoresist treatment, 320 μm square opening (this part becomes the display cell), line width is 30 μm, height continuously changed from 35 μm to 40 μm A lattice-shaped partition wall pattern was prepared, and the substrate with partition walls 1 was obtained.

  The white display medium (negatively charged) and the black display medium (positively charged) were combined and placed in the cell with the same volume so that the volume was 25 vol%, and two substrates were bonded to obtain an information display panel.

  This information display panel has an electric field applied to the display medium even when the voltage applied to the counter electrode is small by narrowing the distance between the substrates as the position is farther from the power connection end of the line-shaped ITO transparent electrode. Since the strength is maintained, the electric field can be applied to all the display media arranged in the display area with the same strength, and the occurrence of variations in the driveability of the display media can be suppressed, and the entire screen is uniform. It was possible to display with image quality.

<Example 2>
[Formation of electrode pattern]
A 30 Ω / □ ITO film (thickness: 200 nm) was formed on the surface of the display screen area (250 mm × 250 mm) of the glass substrate 1 having a thickness of 200 μm by a photoresist method to form a pattern of line ITO electrodes. On the surface of the display screen area (250 mm × 250 mm) of the glass substrate 2 having a thickness of 200 nm, a pattern of line-shaped copper electrodes obtained by etching a sputter-deposited copper thin film was formed.
Thereafter, the partition wall forming material formed on the substrate 1 on which the line-shaped ITO electrode is formed is subjected to CMP (Chemical Chemical Process) so that the length of the line-shaped ITO electrode has an inclination gradient with a maximum thickness of 40 μm and a minimum thickness of 35 μm. (Mechanical polishing) and then photoresist treatment, 320 μm square opening (this part becomes the display cell), line width is 30 μm, height continuously changed from 35 μm to 40 μm A lattice-shaped partition wall pattern was prepared, and the substrate with partition walls 1 was obtained.

  The white display medium (negatively charged) and the black display medium (positively charged) were combined and placed in the cell with the same volume so that the volume was 25 vol%, and two substrates were bonded to obtain an information display panel.

  This information display panel has an electric field applied to the display medium even when the voltage applied to the counter electrode is small by narrowing the distance between the substrates as the position is farther from the power connection end of the line-shaped ITO transparent electrode. Since the strength is maintained, the electric field can be applied to all the display media arranged in the display area with the same strength, and the occurrence of variations in the driveability of the display media can be suppressed, and the entire screen is uniform. It was possible to display with image quality.

<Comparative example>
[Formation of electrode pattern]
An ITO film (thickness: 200 nm) of 30Ω / □ is formed on the surface of the display screen area (250 mm × 250 mm) of the glass substrate 1 and the glass substrate 2 having a thickness of 200 μm by a photoresist method, and a pattern of line ITO electrodes Formed.
After that, a partition wall forming material formed to a thickness of 40 μm on the substrate 1 on which the line-like ITO electrode is formed is subjected to a photoresist treatment to have a 320 μm square opening (this portion becomes a display cell), A grid-like partition wall pattern having a width of 30 μm and a height of 40 μm was produced to obtain a partition wall-equipped substrate 1.

  The white display medium (negatively charged) and the black display medium (positively charged) were combined and placed in the cell with the same volume so that the volume was 25 vol%, and two substrates were bonded to obtain an information display panel.

  Using this information display panel, the same driving as in Example 1 and Example 2 was performed to display an image, but the display in the region far from the power connection end of both line-shaped ITO transparent electrodes showed poor contrast. It became an image and could not be displayed with uniform image quality on the entire screen.

The information display panel of the present invention includes a notebook computer, an electronic notebook, a portable information device called PDA (Personal Digital Assistants), a display unit of a mobile device such as a mobile phone, a handy terminal, an electronic book, an electronic newspaper, an electronic manual ( Electronic manuals), electronic paper such as signboards, posters, bulletin boards such as blackboards and whiteboards, electronic desk calculators, display units for home appliances, automobile supplies, card display units such as point cards and IC cards, electronic advertisements, In addition to information boards, electronic POPs (Point Of Presence, Point Of Purchase advertising), electronic price tags, electronic shelf labels, electronic musical scores, and display units for RF-ID devices, various electronic devices such as POS terminals, car navigation devices, watches, etc. It is suitably used for the display unit.
The information display panel of the present invention can be used as a simple matrix drive display panel or a static drive display panel that does not use a switching element in the panel itself.

(A), (b) is a figure which shows the fundamental structure of the information display panel of this invention. (A), (b) is a figure which shows the fundamental structure of the information display panel of this invention. It is a figure which shows the fundamental structure of the information display panel of this invention. It is a figure which shows the fundamental structure of the information display panel of this invention. (A)-(c) is a figure which shows the outline | summary of the information display panel of this invention. (A)-(c) is a figure which shows the example 1 of arrangement | positioning of the information display panel of this invention. (A)-(c) is a figure which shows the example 2 of arrangement | positioning of the information display panel of this invention. It is a figure which shows an example of the shape of the partition in the information display panel of this invention.

Explanation of symbols

1, 2 Substrate 3 Display medium (particle group)
3W White display medium 3B Black display medium 3R Red display medium 3G Green display medium 3BL Blue display medium 3Wa White display particles 3Ba Black display particles 4 Bulkheads 5, 6 Line electrodes 8 Insulating liquid 9 Microcapsules 10, 11 Leader 12 , 13 Power connection member 14 Inter-substrate distance securing member 21-1 First cell (pixel)
21-2 Second cell (pixel)
21-3 Third cell (pixel)
22R Red color filter 22G Green color filter 22B Blue color filter

Claims (3)

A display medium made of display particles having optical reflectivity and chargeability is enclosed in a space between two substrates, at least one of which is transparent, and line electrodes provided on the two substrates are formed to intersect each other. An information display panel that displays information such as an image by moving the display medium by applying an electric field from the counter electrode to the display medium,
The inter-substrate distance is continuously changed so that the inter-substrate distance corresponding to the position becomes narrower as the position is farther from the power connection end of the line-shaped transparent electrode among the line-shaped electrodes. Characteristic information display panel.   The information display panel is a charged particle drive type information display panel, and is a dot matrix type passive drive that drives a display medium by applying an electric field between counter electrodes formed by crossing opposing line-shaped electrodes. The information display panel according to claim 1, wherein the information display panel is a system.   The information display panel according to claim 1, wherein a space between two substrates of the information display panel is a gas space.

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