JP2008209504A - Driving method of panel for information display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the driving method of a panel for information display capable of reducing the load of a power source capacity during start-up and further capable of obtaining high contrast. <P>SOLUTION: The driving method of the panel for information display includes displaying information such as the images, by using counter electrodes and applying a pulse-like drive voltage between the counter electrodes with respect to the display media used in the panel for information display constituted by filling at least one kind of the display media composed of at least one kind of the particles in a space between two opposing substrates at least one of which is transparent to generate an electric field within the substrates and moving the display media by the electric field. In the driving method of the panel for information display requiring at least two potentials, the absolute value of the at least one potential of the one electrode and the other electrode of the paired electrodes is lowered from the state of applying the prescribed potential to each of the one electrode and the other electrode of the pair electrodes and thereby the drive voltage is applied between the paired electrodes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display medium used in an information display panel having a configuration in which at least one kind of display medium composed of at least one kind of particles is enclosed in a space between two opposing substrates, at least one of which is transparent, A method for driving an information display panel that displays information such as images by moving a display medium by an electric field generated in a substrate by applying a pulsed drive voltage between the counter electrodes using the counter electrode. The present invention relates to a method for driving an information display panel that requires a drive potential of at least two potentials.

Conventionally, a display medium is sealed between two opposing substrates, at least one of which is transparent, and an electric field generated in the substrate by applying a pulsed voltage between electrodes provided on each substrate. A driving method of an information display panel that moves and displays information such as an image is known (for example, see Patent Document 1).
JP 2005-331903 A

  In the conventional driving method of the information display panel described above, FIG. 15A shows an example of voltages applied to the row electrodes and the column electrodes respectively provided on the two substrates, and FIG. As shown in another example of the column electrode and the voltage applied to the column electrode respectively provided on the substrate, the reference voltage is set to 0 V, and the drive threshold voltage at which the display medium starts moving from the reference voltage to the row electrode A pulse voltage that rises to the above voltage (here, ± 70 V) is applied, and a reference voltage of 0 V is applied to the column electrode, thereby driving the display medium to the information display panel. Information such as images was displayed. However, as in the conventional method for driving an information display panel described above, when a pulse-like voltage rising from a reference voltage of 0 V is used for driving, the power capacity of the power supply capacity at the time of rising is increased. There was a problem of increased load. Further, in general, there has been a demand for an information display panel to obtain a driving method capable of increasing the contrast of the information display panel.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a method for driving an information display panel that can reduce the load on the power supply capacity at the time of rising of the display medium drive and obtain high contrast. It is something to try.

  The information display panel driving method according to the present invention is an information display panel having a configuration in which at least one type of display medium made of at least one type of particles is enclosed in a space between two opposing substrates, at least one of which is transparent. Display information such as images by moving the display medium by the electric field generated in the substrate by applying a pulsed drive voltage between the counter electrodes using the counter electrode for the display medium used in In a method for driving an information display panel that requires a driving potential of at least two potentials, a predetermined potential is applied to each of one electrode and the other electrode of the counter electrode. By lowering the absolute value of the potential of at least one of the counter electrode and the other electrode from the state (fall), the rise of the absolute value voltage (rise) By utilizing the voltage change of falling (fall), it is characterized in that a drive voltage is applied between the counter electrode.

  As a preferred example of the method for driving the information display panel according to the present invention, a state in which a predetermined potential is applied to one electrode of a counter electrode having a fall of the absolute value of the potential (fall) From the rise of the absolute value voltage, by raising the absolute value of the potential from (rise) and by making the absolute value of the potential to fall (fall) larger than the absolute value of the rise (rise) potential Applying a driving voltage between the counter electrodes using the falling voltage change, HV (predetermined high potential: driving voltage), MV (medium potential whose absolute value is smaller than the absolute value of HV), LV ( From the state in which one electrode of the counter electrode is set to HV or MV and the other electrode of the counter electrode is set to HV or MV. The applied voltage of the electrode V is applied voltage of the other electrode of the counter electrode is set to HV, or the applied voltage of the other electrode of the counter electrode is set to LV, and the applied voltage of one electrode of the counter electrode is set to HV, so that the drive voltage HV is Three potentials: HV (predetermined high potential: drive voltage), MV (medium potential whose absolute value is smaller than the absolute value of HV), and LV (low potential whose absolute value is smaller than the absolute value of MV) The same potential of HV or MV is applied to one electrode and the other electrode of the counter electrode, and from the state of HV or MV, the applied voltage of one electrode of the counter electrode is LV and the applied voltage of the other electrode is HV Alternatively, the drive voltage HV may be applied between the counter electrodes by setting the applied voltage of the other electrode of the counter electrode to LV and the applied voltage of one electrode to HV.

  According to the present invention, the absolute value of the potential of at least one of the one electrode and the other electrode of the counter electrode is fallen (fall) from a state where a predetermined potential is applied to each of the one electrode and the other electrode. By applying a drive voltage between the counter electrodes, it is possible to reduce the load of the power source capacity at the time of the rise of the display medium drive, and to obtain a method for driving the information display panel capable of obtaining a high contrast. Can do.

  FIGS. 16A and 16B are diagrams showing examples of circuits for performing rise drive and fall drive, respectively. As shown in FIGS. 16A and 16B, both the rising drive circuit and the falling drive circuit are configured by combining a Pch transistor and an Nch transistor. In general, when the areas of the Nch and Pch transistors are the same, the Nch transistor can pass a larger amount of current. Therefore, in the case of 70V → 0V (voltage fall: fall) shown in FIG. The change is faster than in the case of 0V → 70V (voltage rise: rise) shown in 16 (a). In the present invention, the intended effect is obtained by forming the driving voltage by using the fall which is rapidly changed.

Here, the definition of the voltage application method: voltage rise (rise) and voltage fall (fall) to the information display panel 100 that is the target of the driving method of the present invention will be described.
(1) Falling voltage (fall):
As in the case of 70V → 0V, 50V → 20V, the voltage is applied in the direction from the high potential toward the potential zero. The same applies to the negative potential side, and the voltage is applied in the direction from the high potential (high negative potential) to the low potential (potential zero side) as in the case of −70 V → 0 V, −50 V → −20 V.
(2) Rise of voltage:
As in the case of 0V → 70V and 20V → 50V, the voltage is applied in the direction from the low potential (potential zero side) to the high potential. The same applies to the negative potential side, as in the case of 0V → −70V, −20V → −50V, and the voltage is applied in the direction from the low potential (potential zero side) to the high potential (high negative potential).

  First, a basic configuration of an information display panel that is an object of the driving method of the present invention will be described. In the information display panel which is a target of the driving method of the present invention, an electric field is applied to a display medium sealed between two opposing substrates. In accordance with the applied electric field direction, the charged display medium is attracted by the electric field force or the Coulomb force, and the display medium changes the moving direction according to the change of the electric field direction, thereby displaying information such as an image. Therefore, it is necessary to design the information display panel so that the display medium can move uniformly and maintain stability when rewriting the display repeatedly or when displaying the display information continuously. Here, as the force applied to the particles constituting the display medium, in addition to the force attracting each other by the Coulomb force between the particles, an electric mirror image force between the electrode and the substrate, an intermolecular force, a liquid cross-linking force, gravity and the like can be considered.

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

  In the example shown in FIGS. 1A and 1B, at least two kinds of display media 3 (here, white display medium particles 3Wa) having at least one kind of particles and having different optical reflectance and charging characteristics. A white display medium 3W made of a group of particles and a black display medium 3B made of a particle group of black display medium particles 3Ba) are applied to the individual electrodes 5 and 6 provided outside the substrates 1 and 2. The black display medium 3B is moved to be perpendicular to the substrates 1 and 2 in accordance with the electric field generated by the observer and the black display medium 3B is visually recognized by the observer, or the white display medium 3W is visually recognized by the observer. Is displayed. In the example shown in FIG. 1B, in addition to the example shown in FIG. 1A, a partition 4 is provided between the substrates 1 and 2, for example, in the form of a lattice to form a cell. In addition, in FIG. 1B, the partition in front is omitted.

In the example shown in FIGS. 2A and 2B, at least two or more types of display media 3 (here, white display medium particles 3Wa) having different optical reflectance and charging characteristics composed of at least one type of particles. A line electrode 5 provided on the inner side of the substrate 1 and a line electrode provided on the inner side of the substrate 2 for the white display medium 3W and the black display medium 3B of the black display medium particles 3Ba). 6 is moved vertically to the substrates 1 and 2 in accordance with an electric field generated by applying a voltage between them and the black display medium 3B is visually recognized by the observer to display black or white display The medium 3W is visually recognized by an observer and white display is performed. In the example shown in FIG. 2B, a cell is formed by providing partition walls 4 between the substrates 1 and 2, for example, in a lattice shape. Further, in FIG. 2 (b), the front partition is omitted.
The electrode may be provided inside the substrate, outside the substrate, or embedded in the substrate.

  In the example shown in FIGS. 3A and 3B, at least two kinds of display media 3 (here, white display medium particles 3Wa) having different optical reflectivity and charging characteristics composed of at least one kind of particles. A white display medium 3W composed of a group of particles and a black display medium 3B composed of a particle group of black display medium particles 3Ba), and an individual electrode 5 provided inside the substrate 1 and an individual electrode provided inside the substrate 2 6 is moved vertically to the substrates 1 and 2 in accordance with an electric field generated by applying a voltage between them and the black display medium 3B is visually recognized by the observer to display black or white display The medium 3W is visually recognized by an observer and white display is performed. In the example shown in FIG. 3B, for example, a partition 4 is provided in a lattice shape between the substrates 1 and 2 to form cells. Moreover, in FIG.3 (b), the partition in front is abbreviate | omitted.

In the example shown in FIGS. 4A and 4B, the display medium 3 (here, a particle group of white display medium particles 3Wa) having at least an optical reflectance and chargeability, which is composed of at least one kind of particles. The white display medium 3W) is moved in a direction parallel to the substrates 1 and 2 according to the electric field generated by applying a voltage between the individual electrode 5 and the individual electrode 6 provided on the substrate 1, The white display medium 3W is visually recognized by the observer to display white, or the color of the electrode 6 or the substrate 1 is visually recognized by the observer to display the color of the electrode 6 or the substrate 1. In the example shown in FIG. 4B, a cell is formed by providing, for example, a lattice-like partition wall 4 between the substrates 1 and 2. Moreover, in FIG.4 (b), the partition in front is abbreviate | omitted.
The electrode may be provided inside the substrate, outside the substrate, or embedded in the substrate.

In the example shown in FIGS. 5A to 5D, first, as shown in FIGS. 5A and 5C, at least optical reflectivity and charging characteristics that are composed of at least one kind of particles are different. Two or more types of display media 3 (here, a white display medium 3W composed of particles of white display medium particles 3Wa and a black display medium 3B composed of particles of black display medium particles 3Ba are shown) are formed by partition walls 4. In each of the formed cells, an electric field generated by applying a voltage between opposing counter electrodes formed by the external electrode 11 provided outside the substrate 1 and the external electrode 12 provided outside the substrate 2 The substrate 1 and 2 are moved vertically. Then, the white display medium 3W is visually recognized by the observer as shown in FIG. 5B, or white display is performed, or the black display medium 3B is visually recognized by the observer as shown in FIG. 5D. The display is black. In addition, in FIG. 5 (a)-(d), the partition in front is abbreviate | omitted. In addition, a conductive member 13 is provided inside the substrate 1, and a conductive member 14 is provided inside the substrate 2. This conductive member may not be provided.
The electrode may be provided inside the substrate, outside the substrate, or embedded in the substrate.

  The above description is similarly applied to the case where the white display medium 3W including the particle group is replaced with the white display medium including the powder fluid and the black display medium 3B including the particle group is replaced with the black display medium including the powder fluid. I can do it. The powder fluid will be described later.

  In the example shown in FIGS. 6 and 7, another example in which black and white display is performed using the line electrodes 5 and 6 is described, similar to the example shown in FIGS. 2A and 2B. In the example shown in FIG. 6, the white display medium 3W and the black display medium are used instead of the cells formed by the partition walls 4 filled with the white display medium 3W and the black display medium 3B shown in FIGS. A microcapsule 9 filled with 3B together with the insulating liquid 8 is used. Further, in the example shown in FIG. 7, instead of the cell formed by the partition 4 filled with the white display medium 3 </ b> W and the black display medium 3 </ b> B shown in FIGS. A microcapsule 9 filled with an insulating liquid 8 is used as a display medium with a rotating ball 10 that is separately coated and has polarities opposite to each other. In both examples shown in FIGS. 6 and 7, monochrome display can be performed in the same manner as the example shown in FIG.

  The information display panel driving method of the present invention is a state in which a predetermined potential is applied to each of one electrode and the other electrode of the counter electrode when the information display panel having the above-described configuration is driven with a pulsed voltage. The driving voltage is applied between the counter electrodes by causing the absolute value of the potential of at least one of the one electrode and the other electrode of the counter electrode to fall. Hereinafter, a method for driving the information display panel of the present invention will be specifically described.

  FIGS. 8A and 8B are diagrams for explaining an example of a method for driving the information display panel according to the first embodiment of the present invention. In this example, in order to form the drive voltage 70V, in the case of FIG. 8A, MV = 60V, HV = 90V, and LV = 20V, and the voltage in the row (ROW) is 30V (= 90-60). Although the voltage is raised, the voltage is 40 V (= 60−20) and the voltage falls in the column (COL). In this case, the falling edge of the voltage waveform is used rather than the conventional method in which the voltage is raised from 20 V to 90 V to produce the driving voltage 70 V, and the drive electric field is formed at a higher speed. The displayed image contrast is improved.

In the case of FIG. 8B, the drive voltage 70V is formed using the same method as the example shown in FIG. MV = −60V, HV = −90V, LV = −20V, and the voltage is reduced to 40V (= −20V − (− 60)) in the row (ROW), but the voltage is decreased in the column (COL). 30V (= −60 − (− 90)) is rising. By using the falling edge of the voltage waveform as compared with the conventional method, the drive electric field is formed subsequently, and the displayed image contrast is improved.
In the example shown in FIGS. 8A and 8B, the voltages applied to the rows and columns can be reversed.

  FIGS. 9A and 9B are diagrams for explaining an example of a method for driving the information display panel according to the second embodiment of the present invention. In this example, in order to form the drive voltage 70V, in the case of FIG. 9A, MV = 50V, HV = 70V, LV = 0V, and the voltage in the row (ROW) is 20V (= 70-50). The voltage is raised, but the voltage is reduced to 50 V (= 70-50) in the column (COL). In this case, the falling edge of the voltage waveform is used and the formation of the driving electric field is performed at a higher speed than the conventional method in which the driving voltage 70V is generated by raising the voltage from 0V to 70V. The displayed image contrast is improved.

  In the case of FIG. 9B, the driving voltage 70V is formed using the same method as the example shown in FIG. MV = −50V, HV = −70V, LV = 0V, the voltage is 50V (= 0 − (− 50)) falling in the row (ROW), but the voltage is 20V (falling) in the column (COL). = −50 − (− 70)) Rise. Compared to the conventional method, the falling edge of the voltage waveform is used, the drive electric field is formed at a high speed, and the displayed image contrast is improved.

  In the above-described MV reference drive according to the first and second embodiments, the difference between (increase) <(smaller) between the increase and decrease than the absolute value of the voltage reference value MV. It is a characteristic that there is a relationship. In other words, in the first embodiment shown in FIGS. 8A and 8B, this relationship is satisfied with the increase amount = | 60−90 | = 30 and the decrease amount = | 60−20 | = 40. Further, in the second embodiment shown in FIGS. 9A and 9B, this relationship is satisfied with a larger amount = | 50−70 | = 20 and a smaller amount = | 50−0 | = 50. Further, the intermediate potential MV can be arbitrarily set.

  FIGS. 10A and 10B are diagrams for explaining an example of a method for driving the information display panel according to the third embodiment of the present invention. When the falling edge is used in the present invention, it is more effective to apply a plurality of pulses as shown in FIG. 10B than a single pulse as shown in FIG. At this time, the larger the number of pulses, the more effective, but the power consumption may increase accordingly, and the time loss also increases. Therefore, it is preferable to use in the range of 2 to 100 times.

  FIG. 11 is a diagram for explaining an example of a drive circuit for executing the method for driving the information display panel of the present invention. In the example shown in FIG. 11, 11 is a DC power supply, C1 is an electric field capacitor, RT1 and RT2 are switching transistors on the ROW (row) electrode side, and CT1 and CT2 are switching transistors on the COL (column) electrode side. In the drive circuit shown in FIG. 7, as shown in Tables 1 and 2 below, ON / OFF of the switching transistor is controlled, a predetermined potential is applied to the ROW (row) electrode and the COL (column) electrode, and the drive voltage is set. Applied between the counter electrodes. Here, the driving of the conventional example is shown in Table 1, and the driving of the example of the present invention is shown in Table 2.

  In the driving method in the driving circuit described above, display characteristics can be improved by increasing the transition time to the applied potential. In particular, in a circuit configuration in which a Pch transistor is used for RT1 and CT1 and an Nch transistor is used for RT2 and CT2, display characteristics are improved by changing the drive voltage using an Nch transistor having high mobility. In order to realize the same effect with a Pch transistor, the size of the Pch transistor must be increased, which is not likely to be costly.

  FIG. 12 is a diagram for explaining the influence of the voltage drop of the power source in the conventional example and the example of the present invention. In the example shown in FIG. 12, when a high potential (absolute value) is applied to the panel, the driving method using the conventional circuit includes the voltage drop of the power supply in the rise time. Since the potential applied between the panels is set to the same potential during the drop time, the influence of the voltage drop is not included in the voltage transition time and does not affect the display characteristics. As can be seen from the description of FIG. 12, a large-capacity power supply and peripheral parts are required to realize the conventional driving method, which increases the cost. On the other hand, in the driving method of the present invention, since the rise time is not affected by the voltage drop of the power supply, an increase in the component mounting space can be avoided.

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

  As for the substrate, at least one substrate is the transparent substrate 2 from which the color of the display medium can be confirmed from the outside of the information display panel, and a material having high visible light transmittance and good heat resistance is preferable. The substrate 1 may be transparent or opaque. Examples of substrate materials include polymer sheets such as polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyethylene, polycarbonate, polyimide, and acrylic, flexible materials such as metal sheets, and glass and quartz. An inorganic sheet having no flexibility is mentioned. The thickness of the substrate is preferably from 2 to 5000 μm, more preferably from 5 to 2000 μm. If it is too thin, it will be difficult to maintain the strength and the spacing uniformity between the substrates, and if it is thicker than 5000 μm, it will be a thin information display panel. Is inconvenient.

  Electrode forming materials include metals such as aluminum, silver, nickel, copper, gold, indium tin oxide (ITO), zinc-doped indium oxide (IZO), indium oxide, antimony tin oxide (ATO), conductive tin oxide Conductive metal oxides such as conductive zinc oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene are exemplified and used as appropriate. 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. The method of apply | coating is used. The electrode provided on the display surface side substrate 2 which is on the viewing side and needs to be transparent needs to be transparent, but the electrode provided on the back side substrate 1 does not need to be transparent. In any case, the above-mentioned material that can be patterned and is electrically conductive can be suitably used. Note that the electrode thickness is not particularly limited as long as the conductivity can be secured and the light transmittance is not hindered, 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 1 are the same as those of the electrode provided on the display surface side substrate described above, but need not be transparent. In this case, the external voltage input may be superimposed with direct current or alternating current.

The shape of the partition walls 4 provided on the substrate as required is appropriately set appropriately depending on the type of display medium involved in display, the shape and arrangement of electrodes to be arranged, and is not limited in general. The height of the partition is adjusted to 100 to 100 μm, preferably 3 to 50 μm, and the height of the partition wall to 10 to 100 μm, preferably 10 to 50 μm.
In forming the partition wall, a both-rib method in which ribs are formed on each of the opposing substrates 1 and 2 and then bonded, and a single-rib method in which ribs are formed only on one substrate are conceivable. In the present invention, any method is preferably used.
As shown in FIG. 13, the cells formed by the partition walls made of these ribs are illustrated in 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 the information display panel of the present invention, and among these, a photolithography method using a resist film and a mold transfer method are suitably used.

  Next, for example, the powder fluid used as the display medium in the present invention will be described. As for the name of the powder fluid used in the information display panel of the present invention, the present applicant has obtained the right of “Electronic Powder Fluid (registered trademark): Registration No. 4636931”.

  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, liquid crystal is defined as an intermediate phase between a liquid and a solid, and has fluidity that is a characteristic of liquid and anisotropy (optical properties) that is a characteristic of solid (Heibonsha: Encyclopedia) . On the other hand, the definition of 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 fluids. 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. Is a gas-solid fluidized bed that is in a state where it can easily flow when it balances with gravity, and it is also called a liquid-solid fluidized state that is fluidized by a fluid (ordinary) Company: Encyclopedia). As described above, the gas-solid fluidized bed body and the liquid-solid fluid are in a state of using a gas or liquid flow. In the present invention, it has been found that a substance in a state of fluidity can be produced 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 is the characteristic of the above-mentioned particles. It is a substance that is extremely unaffected and exhibits a unique state with high fluidity. 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 solid substance is regarded as a dispersoid in the information display panel of the present invention. To do.

An information display panel that is an object of the driving method of the present invention is a powder that exhibits high fluidity in an aerosol state in which solid particles are stably suspended as a dispersoid, for example, in a gas between opposing substrates, at least one of which is transparent. This type of powder fluid is so fluid that it cannot measure the angle of repose, which is an index indicating the fluidity of the powder, and is easily stabilized by the Coulomb force with a small electric field. Can be moved.
As described above, for example, the powder fluid used as the display medium in the present invention is a substance in the intermediate state between the fluid and particles that exhibits fluidity by itself without borrowing the force of gas or liquid. It is. This powder fluid can be in an aerosol state in particular, and in the information display panel of the present invention, it is used as a display medium in a state where a solid substance floats relatively stably as a dispersoid in the gas.

Next, display medium particles (hereinafter, also referred to as particles) constituting the display medium in the information display panel that is the target of the driving method of the present invention will be described. The display medium particles are composed of the display medium particles as they are to form a display medium, or are combined with other particles to form a display medium, or adjusted and configured to become a powder fluid to form a display medium. Or used.
The particles can 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 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 adhesive force with the substrate.

  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), and nitroimidazole derivatives. Examples of the positive charge control agent include nigrosine dyes, triphenylmethane compounds, quaternary ammonium salt compounds, polyamine resins, imidazole derivatives, and the like. 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.
The above colorant can be blended to produce display medium particles having a desired color.

  The particles for display medium 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 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 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 set to 50 or less, preferably 10 or less. It is essential. 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.

  The charge amount of the display medium particles naturally depends on the measurement conditions, but the charge amount of the display medium particles in the information display panel is almost the same as the initial charge amount, the contact with the partition walls, the contact with the substrate, and the elapsed time. It was found that depending on the charge decay, the saturation value of the charging behavior of the particles for the display medium is a dominant factor.

  As a result of intensive studies, the present inventors have been able to evaluate the range of proper charging characteristics of display medium particles by measuring the charge amount of the particles used in the display medium using the same carrier particles in the blow-off method. I found.

Furthermore, when applied to an information display panel in which the display medium is driven in gas, it is important to manage the gas in the gap surrounding the display medium between the substrates, which 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.
For example, in FIG. 1 (a), (b) to FIG. 4 (a), (b), the void portion refers to electrodes 5 and 6 (electrodes of the substrate from the portion sandwiched between the opposing substrate 1 and substrate 2). It refers to the gas portion in contact with the so-called display medium, excluding the occupied portion of the display medium 3, the occupied portion of the partition wall 4 (when the partition wall is provided), and the seal portion of the information display panel. .
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 distance between the substrates in the information display panel that is the subject of the 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 adjusted to 10 to 500 μm, preferably 10 to 200 μm. .
The volume occupation ratio of the display medium in the gas space between the opposing substrates is preferably 5 to 70%, more preferably 5 to 60%. If it exceeds 70%, the movement of the display medium is hindered, and if it is less than 5%, the contrast tends to be unclear.

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

<Example>
An information display panel was manufactured by the following process.
(1) Step of forming partition walls (ribs) and electrode patterns on the substrate;
(2) filling the display medium into the substrate;
(3) Step of removing unnecessary display medium on the partition;
(4) an adhesive layer forming step on the partition; and (5) a bonding step of two substrates.
Material: Glass, ITO line electrodes of 30Ω / □ were formed on the surfaces of the substrate 1 and the substrate 2 having a thickness of 200 μm, respectively. Thereafter, on the substrate 2 on which the ITO electrode is formed, a 320 μm square opening (this portion becomes a display cell) and a grid-like partition wall pattern having a line width of 30 μm and a height of 40 μm are prepared by a photoresist method. A ribbed substrate was obtained. An equivalent amount was placed in the cell so that the white display medium (negatively charged) and the black display medium (positively charged) were combined to 25 vol%.

  Using the information display panel and the drive circuit described above, the conventional LV reference is obtained by raising the potential with 0V as a reference and the pulse voltage is obtained with 70V as the reference according to the present invention as the reference. The contrast (represented as CNT in the figure) after 20,000 times of image erasure and image writing to obtain a full black display and a full white display was obtained according to each of the HV standards. . For contrast measurement, an optical densitometer RD-19I manufactured by Gretag Macbeth was used. The results are shown in FIG. From the results shown in FIG. 14, it can be seen that, with the HV standard of the example of the present invention, the contrast increases by about 0.7 when erasing the image and the contrast increases by about 0.3 when the image is written, as compared with the conventional example. From this result, it can be seen that by using the HV standard of the example of the present invention, a more effective effect can be obtained at the time of image erasure that requires power supply.

  The driving method of the present invention includes a notebook computer, an electronic notebook, a PDA (Personal Digital Assistants) portable information device, a display unit of a mobile device such as a mobile phone, a handy terminal, an electronic book, an electronic newspaper, an electronic manual (instruction manual) E-paper), billboards such as signboards, posters, blackboards (whiteboards), electronic desk calculators, display units for home appliances, automobile supplies, etc., card displays such as point cards and IC cards, electronic advertisements, information boards In addition to electronic POP (Point Of Presence, Point Of Purchase advertising), electronic price tag, electronic shelf label, electronic score, display part of RF-ID equipment, display part of various electronic equipment such as POS terminal, car navigation device, clock, etc. It is suitably used for an information display panel used in the above.

  The driving method of the present invention can be applied to various types of driving systems such as a simple matrix driving display panel and a static driving display panel that do not use a switching element in the panel itself. Further, the present invention can be applied to an external electric field forming means in an external electric field driving display panel using an external electric field.

(A), (b) is a figure which shows an example of the information display panel used as the object of the drive method of this invention, respectively. (A), (b) is a figure which shows the other example of the information display panel used as the object of the drive method of this invention, respectively. (A), (b) is a figure which shows the further another example of the information display panel used as the object of the drive method of this invention, respectively. (A), (b) is a figure which shows the further another example of the information display panel used as the object of the drive method of this invention, respectively. (A)-(d) is a figure which shows the further another example of the information display panel used as the object of the drive method of this invention, respectively. It is a figure which shows the further another example of the information display panel used as the object of the drive method of this invention. It is a figure which shows the further another example of the information display panel used as the object of the drive method of this invention. (A), (b) is a figure for demonstrating an example of the drive method of the information display panel which concerns on 1st Example of this invention, respectively. (A), (b) is a figure for demonstrating the other example of the drive method of the information display panel which concerns on 1st Example of this invention, respectively. (A), (b) is a figure for demonstrating an example of the drive method of the information display panel which concerns on 2nd Example of this invention, respectively. It is a figure for demonstrating an example of the drive circuit which performs the drive method of the information display panel of this invention. It is a figure for demonstrating the influence of the voltage drop of a power supply in a prior art example and this invention example. It is a figure which shows an example of the shape of the partition in the information display panel used as the object of the drive method of this invention. It is a figure for demonstrating the experimental result in an Example and this invention example. (A), (b) is a figure for demonstrating an example of the driving method of the conventional information display panel, respectively. (A), (b) is a figure which shows an example of the circuit which implements the drive of a rise, and the drive of a fall, respectively.

Explanation of symbols

1, 2 Substrate 3 Display medium (particle group, powder fluid)
3W White display medium 3Wa White display medium particle 3B Black display medium 3Ba Black display medium particle 4 Bulkhead 5, 6 Electrode 7 Black plate 8 Insulating liquid 9 Microcapsule 10 Rotating ball 11, 12 External electrode 13, 14 Conductive member

Claims (4)

  A counter electrode is used for a display medium used in an information display panel having a structure in which at least one kind of display medium composed of at least one kind of particles is sealed in a space between two opposing substrates, at least one of which is transparent. An information display panel driving method for displaying information such as an image by moving a display medium by an electric field generated in a substrate by applying a pulsed driving voltage between the counter electrodes, In a method for driving an information display panel that requires a driving potential of 2 potentials or more, one electrode and the other electrode of the counter electrode from a state where a predetermined potential is applied to each of the one electrode and the other electrode of the counter electrode A driving method for an information display panel, wherein a driving voltage is applied between the counter electrodes by falling the absolute value of at least one of the potentials.   The absolute value of the potential is fallen (rise) by raising the absolute value of the potential from one electrode of the counter electrode that has fallen the absolute value of the potential (fall) from a state where a predetermined potential is applied. 2. The information display device according to claim 1, wherein the drive voltage is applied between the counter electrodes by making the absolute value of the fall potential smaller than the absolute value of the rise potential. Panel drive method.   One of the counter electrodes is used with three potentials: HV (predetermined high potential: drive voltage), MV (medium potential whose absolute value is smaller than the absolute value of HV), and LV (low potential whose absolute value is smaller than the absolute value of MV). Whether the applied voltage of one electrode of the counter electrode is LV and the applied voltage of the other electrode of the counter electrode is HV from the state where the electrode of HV is HV or MV and the other electrode of the counter electrode is HV or MV 3. The drive voltage HV is applied between the counter electrodes by setting the applied voltage of the other electrode of the counter electrode to LV and the applied voltage of one electrode of the counter electrode to HV. A method for driving the described information display panel.   One of the counter electrodes is used with three potentials: HV (predetermined high potential: drive voltage), MV (medium potential whose absolute value is smaller than the absolute value of HV), and LV (low potential whose absolute value is smaller than the absolute value of MV). The same potential of HV or MV is applied to the other electrode and the other electrode, and from the HV or MV state, the applied voltage of one electrode of the counter electrode is set to LV and the applied voltage of the other electrode is set to HV, 3. The information display panel according to claim 1, wherein the driving voltage HV is applied between the counter electrodes by setting the voltage applied to the other electrode to LV and the voltage applied to one electrode to HV. Driving method.

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