WO2006070608A1

WO2006070608A1 - Display drive method for information display panel

Info

Publication number: WO2006070608A1
Application number: PCT/JP2005/023034
Authority: WO
Inventors: Shinya Tsuchida
Original assignee: Bridgestone Corporation
Priority date: 2004-12-27
Filing date: 2005-12-15
Publication date: 2006-07-06

Abstract

There is provided a display drive method for an information display panel for sealing a display medium having an optical reflection ratio and charging characteristic between two substrates, at least one of which is transparent and applying an electric field to the display medium so as to move the display medium and display information. Before displaying information, a pulse voltage is applied to the entire screen once or more times by an application time shorter than the write pulse voltage or a pulse voltage having a small amplitude is applied to the entire screen once or more times. This prevents lowering of the contrast during write of display information, eliminates uneven concentration between pixels, and eliminates an adverse affect of the information display attributed to the durability of the display medium.

Description

Specification

Display driving method of information display panel

Technical field

In the present invention, a display medium having optical reflectivity and chargeability is enclosed between two substrates, at least one of which is transparent, and the display medium is moved by applying an electric field to the display medium. The present invention relates to a display driving method for an information display panel for displaying information. Background art

[0002] Conventionally, as an information display device that replaces liquid crystal (LCD), an information display device using techniques such as an electrophoresis method, an electochromic method, a thermal method, and a two-color particle rotation method has been proposed. .

[0003] 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 various information display devices, and is expected to expand to information display for mobile terminals, electronic paper, and so on. Recently, an electrophoretic method in which a dispersion composed of dispersed particles and a colored solution is microencapsulated and placed between opposing substrates has been proposed and is expected.

However, the electrophoretic method has a problem that the response speed becomes slow due to the viscous resistance of the liquid because the particles migrate in the liquid. In addition, since particles with high specific gravity such as titanium oxide are dispersed in a solution with low specific gravity, they tend to settle, and it is difficult to maintain the stability of the dispersed state. I have it. Even with microencapsulation, the cell size is reduced to the microcapsule level, apparently making the above-mentioned drawbacks difficult to appear, and the essential problems have not been solved.

[0005] On the other hand, a method in which a conductive particle and a charge transport layer are incorporated into a part of a substrate without using a solution has been proposed (for example, non-electrophoresis) that uses a behavior in a solution. (See Patent Document 1). However, since the structure becomes complicated due to the arrangement of the charge transport layer and further the charge generation layer, and it is difficult to uniformly inject the charge into the conductive particles, There is also a problem of lack of stability.

[0006] As a method for solving the various problems described above, a display medium is sealed between two substrates, at least one of which is transparent, and an electric field is applied to the display medium to move the display medium. An information display panel for displaying information is known.

Non-Patent Document 1: Kunihiro Tsuji, 3 others, "New Toner Display Device (1)", July 21, 1999, Annual Meeting of the Imaging Society of Japan (83 times in total) "Japan Hardcopy '99" Proceedings, p.249_ 252

FIG. 10 is a flowchart for explaining an example of a display driving method of a conventional information display panel. In FIG. 10, the drive for displaying information such as an image on the information display panel is performed by erasing the previously displayed information and then applying the write pulse voltage sequentially for each line and writing the data for each line. I was going by. However, in the display driving method of the conventional information display panel described above, a write pulse voltage is applied to each line, and the write pulse voltage is also applied to pixels that do not contribute to display on the line. . For this reason, a crosstalk voltage is applied to the non-selected pixels, and the density of the non-selected pixels changes, resulting in a problem that the contrast is lowered or the density is not uniform between the pixels. Another problem was that the display medium would not move if it was repeatedly displayed, adversely affecting information display.

Disclosure of the invention

[0008] The object of the present invention is to eliminate the above-described problems, to eliminate a decrease in contrast and non-uniform density between pixels when writing display information, and to adversely affect information display due to the durability of the display medium. The present invention intends to provide a display driving method for an information display panel that can be eliminated.

[0009] The display driving method of the information display panel according to the first aspect of the present invention includes sealing a display medium having optical reflectivity and charging characteristics between two substrates, at least one of which is transparent, into the display medium. In the display driving method of the information display panel that displays information by moving the display medium by applying an electric field, a pulse voltage having a shorter application time than the writing pulse voltage is applied to the entire screen before displaying the information. It is characterized by being applied more than once. [0010] Further, in the display driving method of the information display panel according to the second invention of the present invention, a display medium having optical reflectivity and charging characteristics is sealed between two substrates, at least one of which is transparent, Displaying information by moving the display medium by applying an electric field to the display medium In the display driving method of the information display panel, a pulse voltage having an amplitude smaller than the write pulse voltage is applied to the entire screen before displaying the information. It is characterized in that it is applied at least once.

[0011] Further, the display driving method of the information display panel according to the third invention of the present invention encloses a display medium having optical reflectance and charging characteristics between two substrates, at least one of which is transparent, In a display driving method for an information display panel that displays information by moving the display medium by applying an electric field to the display medium, a pulse having a shorter application time and smaller amplitude than the write pulse voltage is displayed before the information is displayed. The voltage is applied to the entire screen at least once.

[0012] Note that, as a preferred example of the display driving method of the information display panel of the present invention, after the displayed information is erased, the predetermined nore voltage according to the first to third inventions described above is applied to the entire screen. May be applied more than once and then information may be displayed.

[0013] According to the present invention, before displaying information, the pulse voltage is applied to the entire screen at least once, whether the application time is shorter than the write pulse voltage or the amplitude is smaller, or the write pulse voltage is written. Applying a pulse voltage with a shorter application time and smaller amplitude than the pulse voltage to the entire screen at least once eliminates the decrease in contrast and non-uniform density between pixels when writing information. It is possible to obtain a display driving method for an information display panel that can eliminate the adverse effect of the resulting information display.

Brief Description of Drawings

[0014] [Fig. L] (a) and (b) are diagrams showing an example of an information display panel which is an object of the display driving method of the present invention.

[FIG. 2] (a) and (b) are diagrams showing other examples of an information display panel which is an object of the display driving method of the present invention.

[FIG. 3] (a) and (b) are views showing still other examples of the information display panel to be subjected to the display driving method of the present invention. FIG. 4 is a flow chart for explaining an example of a display driving method of the information display panel of the present invention.

[FIG. 5] (a) to (d) show examples of pulse voltages used in the display driving method of the present invention.

FIG. 6 is a diagram showing an example of a display image used in a comparative experiment.

FIG. 7 is a diagram showing a pulse voltage with an amplitude VZ2 increased by 1 μsec from 1 β sec to the write pulse voltage width t_l μ sec used in the comparative experiment.

FIG. 8 is a diagram showing the results of a comparative experiment.

FIG. 9 is a diagram showing an example of the shape of a partition wall in the information display panel of the present invention.

FIG. 10 is a flow chart for explaining an example of a display driving method of a conventional information display panel.

BEST MODE FOR CARRYING OUT THE INVENTION

First, a basic configuration of an information display panel that is an object of the display driving method of the present invention will be described. In the information display panel of the present invention, an electric field is applied to a display medium sealed 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 changes the moving direction by the change of the electric field direction due to the switching of the potential. Display is made. Therefore, it is necessary to design an information display panel so that the display medium can move uniformly and maintain the stability when the display information is rewritten repeatedly or when the display information is continuously displayed. is there. Here, the force applied to the particles composing the display medium may be an electromirror force with the electrode or substrate, intermolecular force, liquid bridge force, gravity, etc., in addition to the force attracted by the Coulomb force of the particles. .

An example of an information display panel that is a target of the display driving method of the present invention will be described with reference to FIGS. 1 (a) and (b) to FIGS. 3 (a) and 3 (b).

[0017] In the example shown in Figs. 1 (a) and (b), at least two or more display media 3 (here, white display media) having at least one or more particles having different optical reflectance and charging characteristics are used. White display medium 3W consisting of particles of 3Wa and black display medium 3B consisting of particles of 3Ba black display medium 3B) according to the electric field applied from the outside of the substrates 1 and 2 The black display medium 3B is visually recognized by the observer to display black, or the white display medium 3W is visually recognized by the observer to display white. Yes. In the example shown in FIG. 1 (b), in addition to the example shown in FIG. 1 (a), a partition 4 is provided between the substrates 1 and 2, for example, in the form of a lattice to form a cell. In Fig. 1 (b), the front partition is omitted.

[0018] In the example shown in Figs. 2 (a) and (b), at least two or more display media 3 (here, white display media) having at least one or more kinds of particles and having different optical reflectance and charging characteristics are used. White display medium 3W composed of particles of 3Wa and black display medium 3B composed of particles of 3Ba for black display medium), and electrode 5 provided on substrate 1 and electrode 6 provided on substrate 2 Depending on the electric field generated by applying a voltage between them, the substrate is moved perpendicularly to the substrates 1 and 2, and the black display medium 3B is visually recognized by the observer to display black, or the white display medium 3W is A white color is displayed by the observer. In the example shown in FIG. 2 (b), in addition to the example shown in FIG. 2 (a), a partition 4 is provided between the substrates 1 and 2 to form cells, for example. In FIG. 2 (b), the partition in front is omitted.

[0019] In the example shown in FIGS. 3 (a) and 3 (b), one type of display medium 3 (here, particles for white display medium) having optical reflectivity and chargeability composed of at least one type of particles. A white display medium consisting of 3Wa particles (showing 3W) in a direction parallel to the substrates 1 and 2 according to the electric field generated by applying a voltage between the electrode 5 and the electrode 6 provided on the substrate 1. Move the white display medium 3W to the viewer to display the white color, or display the color of the electrode 6 or the substrate 1 to the viewer and display the color of the electrode 6 or the substrate 1 Yes. In the example shown in FIG. 3 (b), in addition to the example shown in FIG. 3 (a), for example, a lattice-shaped partition wall 4 is provided between the substrates 1 and 2 to form a cell. In Fig. 3 (b), the partition in front is omitted.

[0020] The above description is the same when the white display medium 3W composed of particle groups is replaced with a white display medium composed of powdered fluid, and the black display medium 3B composed of particle groups is replaced with a black display medium composed of powdered fluid. It can be applied to. The powder fluid will be described later.

FIG. 4 is a flowchart for explaining an example of the display driving method of the information display panel of the present invention. The present invention will be described according to the example shown in FIG. Delete information such as images. Next, before displaying new information, the pulse voltage with a shorter application time than the write pulse voltage (first invention) or the amplitude smaller than the write pulse voltage is applied to the entire screen, that is, all lines on the screen. A pulse voltage (second invention) or a pulse voltage (third invention) having a shorter amplitude and smaller amplitude than the write pulse voltage is applied one or more times. After that, information is displayed by sequentially applying a write pulse voltage for each line and writing data for each line.

[0022] FIGS. 5A to 5D show examples of pulse voltages. Figure 5 (a) shows the write pulse voltage with amplitude V at application time t. For this write pulse voltage, Fig. 5 (b) shows a pulse voltage with an application time of t / 2 as an example of the pulse voltage (first invention) with a shorter application time than the write pulse voltage. 5 (c) shows a pulse voltage with an amplitude of V / 2 as an example of a pulse voltage with a smaller amplitude than the write pulse voltage (second invention), and Fig. 5 (d) shows a shorter application time than the write pulse voltage. As an example of a pulse voltage with small amplitude (Invention 3), the pulse voltage with application time t / 2 and amplitude V / 2 is shown. In the above example, the application time is set to t / 2 and the amplitude is set to V / 2. This is an example, and other voltages can be used as long as they satisfy the conditions of the above inventions. There is no need.

[0023] Hereinafter, an example in which test images are actually displayed and compared according to the present invention example and the comparative example will be described. First, in the display image shown in FIG. 6, the right half was displayed according to the conventional example shown in FIG. 10, and the left half was displayed according to the third invention of the example of the present invention shown in FIG. That is, in the conventional example in the right half, the information shown in FIG. 6 was displayed immediately after the screen was erased. On the other hand, in the example of the present invention in the left half, after the screen erase, as shown in Fig. 7, the pulse voltage of amplitude V / 2 increased by 1 μsec from 1 μsec to the write pulse voltage width t_ l μsec is sequentially applied. It was applied to the entire screen, and then the information shown in Fig. 6 was displayed.

The results are shown in FIG. The density at the time of erasing was 0.79 for both the inventive example and the conventional example. In FIG. 8, in the conventional example in the right half, from (f) and (g) and the density at the time of erasing 0.79, in (f) and (g), the density value increases due to the crosstalk, and the white color is black. The contrast decreased due to the shift to. Also, for example, the density values (f) and (g), which must have the same density value, differed, and the density did not become uniform between pixels. On the other hand, in FIG. Then, from (b) and (c) and density 0 · 79 at the time of erasure, in (b) and (c), the density value did not change due to the effect of crosstalk, or the change could be suppressed. Therefore, it was possible to suppress the reduction in contrast due to crosstalk, and to make the density nonuniformity between pixels uniform. In addition, from (a) and (e), the inventive example was able to increase the black density S and the contrast as compared with the conventional example. The density (optical density) was measured with a reflection image densitometer RD-191 (manufactured by Macbeth).

Hereinafter, each member constituting the information display panel which is a target of the display driving method of the present invention will be described.

[0026] Regarding the substrate, at least one of the substrates has the above-mentioned characteristics of the present invention, and at least one of the substrates is a transparent substrate 2 on which the color of the display medium 3 can be confirmed from the outside of the panel. A material having high transmittance and good heat resistance is suitable. Substrate 1 can be transparent or opaque. Examples of the substrate material include polymer sheets such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and glass, quartz And non-flexible inorganic sheets. The thickness of the substrate is preferably 2 to 500 / im force S, and more preferably 5 to 2000 / im force S. If it is too thin, the strength and the uniformity of the distance between the substrates will be maintained, and it is thicker than 5000 / m. Inconvenient for a thin information display panel.

[0027] Electrodes for forming electrodes on the information display panel include metals such as aluminum, silver, nickel, copper, and gold, and _conductive materials such as _ITO , indium oxide, conductive tin oxide, and conductive zinc oxide. Examples thereof include conductive polymers such as metal oxides, polyaniline, polypyrrole, and polythiophene, which are appropriately selected and used. The electrode can be formed by, for example, 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 synthetic resin binder. The method of applying is used. The electrode provided on the viewing side (display side) substrate needs to be transparent, but the electrode provided on the back side substrate does not need to be transparent. In any case, the above-mentioned material that is conductive and capable of pattern formation can be suitably used. The electrode thickness is good as long as the conductivity can be secured and the light transmittance is not affected. 3 to 1000 nm, preferably 5 to 400 nm is preferred. The material and thickness of the electrode provided on the rear substrate need not be the same as the electrode provided on the display substrate described above. In this case, the external voltage input may be superimposed with direct current or alternating current.

[0028] If necessary, the shape of the partition walls 4 provided on the substrate is appropriately set according to the type of display medium involved in the display, and is not limited in general, but the width of the partition walls is 2 to: 100 μm, Preferably, the height of the partition wall is adjusted to 3 to 50 μm, and the height of the partition wall is adjusted to 10 to 500 μm, preferably 10 to 200 μm. As shown in FIG. 9, the cells formed by the partition walls made up 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. The shape and the mesh shape are exemplified. It is better to make the part (area of the cell frame) corresponding to the partition wall section visible from the display surface side as small as possible.

[0029] Next, a powder fluid used as a display medium in the information display panel that is a target of the display driving method of the present invention will be described. As for the name of the powder fluid as the display medium of the present invention, the applicant has the right of “Electronic Powder Fluid (registered trademark): Registration No. 4636931”.

[0030] The "powder fluid" in the present invention is a substance in an intermediate state of both fluid and particle characteristics that exhibits fluidity by itself without borrowing the force of gas or liquid. For example, a liquid crystal is defined as an intermediate phase between a liquid and a solid, and has fluidity that is a characteristic of a liquid and anisotropy (optical properties) that is a characteristic of a solid (Heibonsha: Large Encyclopedia). ). On the other hand, the definition of a particle is an object with a finite mass even if it is negligible, and is said to be affected by gravity (Maruzen: Physics Encyclopedia). Here, even in the case of particles, there are special states of gas-solid fluidized bed and liquid-solid fluidized bodies. When gas is flowed from the bottom plate to the particles, upward force is applied to the particles according to the velocity of the gas. When it is balanced with gravity, it is called a gas-solid fluidized bed that is in a state where it can easily flow like a fluid, and a state fluidized by the same fluid is called a liquid-solid fluid. (Heibonsha: Encyclopedia). As described above, the gas-solid fluidized bed body and the liquid-solid fluid body are in a state using a flow of gas or liquid. In the present invention, it has been found that a substance in a state of fluidity can be created specifically without borrowing the force of such gas and liquid, and this is defined as powder fluid. That is, the pulverulent fluid in the present invention is in an intermediate state having both the characteristics of particles and liquid as in the definition of liquid crystal (liquid and solid intermediate phase), and has the characteristics of the particles described above. It is a substance that shows a unique state with high fluidity that is extremely difficult to be affected by gravity. Such a substance can be obtained in an aerosol state, that is, in a dispersion system in which a solid or liquid substance is stably suspended as a dispersoid in a gas, and the information display panel of the present invention disperses the solid substance in a dispersoid. It is what.

[0032] An information display panel to which the display driving method of the present invention is applied is an aerosol in which solid particles are stably suspended as a dispersoid, for example, as a display medium, between opposing substrates, at least one of which is transparent. A powder fluid that exhibits high fluidity in a state is enclosed, and such a powder fluid can be easily and stably moved by a Coulomb force with a small electric field force.

As described above, for example, the powder fluid used as a display medium in the present invention is an intermediate state of both fluid and particle characteristics that exhibit fluidity by themselves without borrowing the force of gas or liquid. It is a substance. This powder fluid can be in an aerosol state in particular, and the information display panel of the present invention is used in a state where a solid substance floats relatively stably as a dispersoid in the gas.

[0033] Next, display medium particles (hereinafter also referred to as particles) constituting the display medium in the information display panel will be described. The display medium particles are composed of the display medium particles as they are to form a display medium. The display medium particles are combined with other particles to form a display medium. Or used.

The particles can contain a charge control agent, a colorant, an inorganic additive, etc., if necessary, in the resin as the main component, if necessary. Examples of resins, charge control agents, colorants, and other additives are given below.

[0034] 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, petital resin, vinylidene chloride resin, melamine resin, phenol resin, fluorine resin, polycarbonate resin, polysulfone Resin, polyether resin, polyamide resin and the like, and two or more kinds can be mixed. In particular, acrylic urethane resin, acrylic silicone resin, acrylic fluororesin, acrylic urethane silicone resin, acrylic urethane fluororesin, fluororesin, and silicone resin are suitable from the viewpoint of controlling the adhesion with the substrate.

The charge control agent is not particularly limited. Examples of the negative charge control agent include salicinoleate metal complexes, metal-containing azo dyes, metal-containing oil-soluble dyes (including metal ions and metal atoms). Quaternary ammonium salt compounds, force-rich allene compounds, boron-containing compounds (boronyl boron complexes), nitroimidazole derivatives, and the like. Examples of the positive charge control agent include a nigue mouth dye, a triphenyl methane compound, a quaternary ammonium salt compound, a polyamine resin, and an imidazole derivative. In addition, metal oxides such as ultrafine silica, ultrafine titanium oxide and ultrafine alumina, nitrogen-containing cyclic compounds such as pyridine and their derivatives and salts, various organic pigments, resins containing fluorine, chlorine, nitrogen, etc. Can also be used as a charge control agent.

[0036] As the colorant, various organic and inorganic pigments and dyes as exemplified below can be used.

[0037] Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, and activated carbon.

Blue colorants include CI Pigment Blue 15: 3, CI Pigment Blue 15, Dark Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Metal-free Phthalocyanine Blue, Phthalocyanine Blue Partial Chlorides, First Sky Blue, Indanthrene Blue BC, etc.

Red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risor red, pyrazolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, Aliza Linleke, Brilliant Carmine 3B, CI Pigment Red 2, etc.

[0038] Yellow colorants include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, Nikkenore Titanium yellow, Neve Nore Yellow, Naftono Reyello S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzine Yellow GR, Quinoline Yellow Lake, Permanente Yellow NCG, Tartra Gin Lake, CI Pigment Yellow 12 etc.

Examples of green colorants include chrome green, chromium oxide, pigment green B, C.I. Pigment Green 7, Malachite Green Lake, Final Yellow Green G, and the like. Orange colorants include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, nonolecan orange, indanthrene brilliant orange RK: benzidine orange G, indanthrene brilliant orange GK :, CI pigment orange 3 1 etc.

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.

[0039] 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 Niguchi Shin, Methylene Blue, Rose Bengal, Quinoline Yellow, and Ultramarine Benole.

[0040] 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. Examples include orange, titanium yellow, bitumen, ultramarine, cobalt violet, 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 preferred as a black pigment, and titanium oxide is preferred as a white pigment.

[0041] The average particle diameter d (0.5) of the particles of the present invention is preferably in the range of 0.:! To 20 μm, and preferably uniform. When the average particle diameter d (0.5) is larger than this range, the display is not clear. When 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.

[0042] Further, in the present invention, the particle size distribution Sp of each particle is represented by the following formula. An 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 expressed by / im that the particle size is 50% larger than this, and 50% smaller than this, and d (0.1) is the ratio of particles below 10%. The particle diameter is expressed in μm, and d (0.9) is the numerical value expressed in xm when the particle size is 90% or less.) By keeping Span within 5 or less, It is possible to move as a uniform display medium with uniform size.

[0043] Further, regarding the correlation of each particle, the ratio of the d (0.5) of the particles having the smallest diameter to the d (0.5) of the particles having the largest diameter among the used particles is 50 or less, preferably 10 or less. It is important to do this. Even if the particle size distribution Span is reduced, particles with different charging properties move in opposite directions, so that particles with close particle sizes can easily move in the opposite direction by the equivalent amount. Is preferred, and this is in this range

[0044] The particle size distribution and particle size described above can be obtained from a laser diffraction / scattering method or the like. When laser light is irradiated onto the particles to be measured, a light intensity distribution pattern of diffracted / scattered light is generated spatially, 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 were introduced into a nitrogen stream, and attached analysis software (software based on volume reference distribution using Mie theory) The particle size and particle size distribution can be measured.

[0045] Although the charge amount of the display medium particles naturally depends on the measurement conditions, the charge amount of the display medium particles in the information display panel is almost the initial charge amount, the contact with the partition walls, the contact with the substrate, It was found that the saturation value of the charging behavior of the particles for display media was a dominant factor depending on the charge decay with time.

[0046] As a result of intensive studies, the present inventors measured the charge amount of the particles used for the display medium using the same carrier particles in the blow-off method, and thus the range of the appropriate charging characteristic value of the particles for the display medium. It was found that can be evaluated. [0047] Further, when a display medium such as particles composed of particles for display medium or a powder fluid is applied to a dry information display panel, the gas in the void surrounding the display medium between the substrates can be managed. It is important and contributes to improved display stability. Specifically, it is important that the relative humidity at 25 ° C is 60% RH or less, preferably 50% RH or less for the gas humidity in the voids.

This gap is defined by the electrodes 5 and 6 (electrodes inside the substrate) from the portion sandwiched between the opposing substrates 1 and 2 in FIGS. 1 (a), (b) to 3 (a), (b). ), The display medium (particle group or powdered fluid) 3 occupies the area, the partition 4 occupies (when the partition is provided), and the so-called display medium except the seal part of the information display panel. It shall refer to the gas part.

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 must be sealed in the information display panel so that the humidity is maintained. For example, filling of the display medium and assembly of the information display panel are performed in a predetermined humidity environment. It is important to use sealing materials and sealing methods that prevent moisture from entering from the outside.

The present invention can also be applied to a case where a display medium composed of particles for display medium is driven to display in an insulating liquid.

[0048] The distance between the substrates in the information display panel that is the target of the display driving method of the present invention is not limited as long as the display medium can be moved and the contrast can be maintained, but is usually 10 to 500 / im, preferably Adjusted to 10-200 μm.

When a particle group or powder fluid is used for the display medium, the volume occupancy of the display medium in the space between the opposing substrates (in gas or liquid) is preferably 5 to 70%, more preferably 5 to 60%. It is. If it exceeds 70%, the movement of the display medium will be hindered. If it is less than 5%, the contrast tends to be unclear.

Industrial applicability

[0049] Information display panels subject to the display driving method of the present invention include display units of notebook computers, PDAs, mobile phones, handy terminals and other mopile equipment, electronic books, electronic newspapers, etc. Electronic paper, billboards, posters, blackboards, calculators, home appliances, automotive supplies, etc., point cards, card displays such as IC cards, electronic advertisements, electronic points (POP) (Point Of Presence, Point Of Purchase advertising) It is suitable for use in electronic price tags, kameko individual bills, 'good!

Claims

The scope of the claims

[1] A display medium having optical reflectivity and charging characteristics is sealed between two substrates, at least one of which is transparent, and an electric field is applied to the display medium to move the display medium to display information. A display drive method for an information display panel, wherein a pulse voltage having a shorter application time than a write pulse voltage is applied to the entire screen at least once before displaying information.

[2] A display medium having optical reflectivity and charging characteristics is sealed between two substrates, at least one of which is transparent, and an electric field is applied to the display medium, thereby moving the display medium to display information. A display drive method for an information display panel, wherein a pulse voltage having an amplitude smaller than a write pulse voltage is applied to the entire screen at least once before displaying information.

[3] A display medium having optical reflectance and charging characteristics is enclosed between two substrates, at least one of which is transparent, and information is displayed by moving the display medium by applying an electric field to the display medium. In the display driving method for an information display panel, an information display panel is characterized in that a pulse voltage having a shorter application time and smaller amplitude than the write pulse voltage is applied to the entire screen at least once before displaying information. Display drive method.

[4] After erasing the previous information, apply the predetermined pulse voltage described in any one of claims 1 to 3 to the entire screen at least once, and then display the information again. A display driving method for a characteristic information display panel.