JP2004240166A - Method for manufacturing image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply manufacturing an image display device to display an image by applying an electric field to move particles. <P>SOLUTION: In a method for manufacturing an apparatus for displaying the image by applying a voltage to an electrode to move the particles in a structure in which a particle group is sealed in a space formed with a pair of substrates and electrodes and partitions, the opposed substrates are adhered to the partitions, after dispersing the particles into an organic solvent to drop them inside the partitions and vaporizing the solvent. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a rewritable image display device.
[0002]
[Prior art]
Conventionally, as a rewritable image display device, a device using electrophoresis and a device using thermal rewritable ink have been developed. Although the above technology is excellent in memory properties, it has a problem that it is difficult to improve display contrast.
[0003]
Therefore, a display technique using toner has been developed as a method of easily increasing the display contrast. This technology, as disclosed in Japanese Patent Application Laid-Open No. 2002-296623, encloses a plurality of types of particles having different colors and charging characteristics between opposing electrode substrates and applies an electric field to move the particles to form an image. indicate. By stabilizing the amount of charge between the particles, uniform display with high contrast is possible. The white particles can also achieve a high reflectance like paper.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-296623
[Problems to be solved by the invention]
However, in the case of high-definition display, it is necessary to seal the particles in a space having a small volume. Therefore, it is difficult to easily distribute the same amount of particles to each space by a method of sieving through a screen. Furthermore, since the particles are minute, they are scattered by the flow of air, or if they adhere to the spacers, the height of the gap varies, and it is difficult to keep the amount of particles in the partition constant, causing unevenness and uniformity. This poses a problem in producing a configuration capable of displaying images.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is characterized in that particles are mixed with an organic solvent in a space partitioned in advance and a fixed amount of liquid is injected.
[0007]
According to the first aspect of the invention, scattering of the particles can be suppressed by mixing the particles with the organic solvent. Further, by injecting a fixed amount of liquid into a fine partition, control of the amount of particles, which is difficult with particles as they are, is simplified. Further, by evaporating the organic solvent after the injection, particles can be prevented from adhering to the substrate surface and scattering from the inside of the partition when the opposing substrate is installed. Thereby, since the assembly can be performed without scattering the particles while holding a fixed amount of particles in the partition, there is an advantage that the manufacturing process is simplified.
[0008]
According to the second aspect of the present invention, a partition is provided on each of the opposing substrates, particles of different colors or different colors are mixed with an organic solvent, and a predetermined amount of liquid is injected to attach different types of particles to the respective substrates. It is characterized by making it. Thus, in the case of displaying a plurality of particles, if particles having different specific gravities are simultaneously mixed with an organic solvent, it is difficult to inject each of the particles at a constant rate. Further, since the particles are attached to each substrate when the organic solvent is vaporized, the particles do not scatter when assembling the display element, so that the display element can be assembled by a roll-to-roll method, and mass production is possible. It is possible to reduce the cost.
[0009]
According to the third and fourth aspects of the present invention, when the display device manufactured in the first and second aspects is moved, ultrasonic waves are applied to the upper and lower substrates to remove particles adhered to the substrates, and in the case of a plurality of particles, the inside of the partition is removed. In this method, each particle is caused to collide with each other and charged, and when a voltage is applied to the upper and lower substrates, the particles are moved to each substrate and displayed accordingly. By applying ultrasonic waves, the particles attached to the substrate are separated from the substrate, and the aggregated particles are broken up into the original particles, so that the fluidity is improved and high display performance can be obtained.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0011]
(Embodiment 1)
FIG. 1 shows a manufacturing process diagram of the image display device according to the first embodiment. Glass, acrylic resin, or the like is used for the substrate 1 (A). The electrode 2 is formed thereon (B). The electrode 2 is formed of ITO, aluminum, gold, or the like by sputtering or vapor deposition. C is a process of forming the partition 3 by pattern-printing a resin material having a low melting point at regular intervals by screen printing and heat-curing, or performing a photo process using a spin-coated photosensitive resin material through a mask, After the curing, a method of curing can be used. In display, if the height of the gap varies, the display becomes uneven. Therefore, it is desirable that the height be uniform.
[0012]
Next, the white particles 4 and the black particles 5 are mixed with the organic solvent 6, and a fixed amount is injected into each partition (D). The organic solvent is preferably an organic solvent that is easily vaporized, such as acetone, ethanol, propanol, and THF. In the case of a fixed-rate injection, particles can be efficiently distributed into a large number of partitions by simultaneously injecting into a plurality of partitions by inkjet. When it is displayed that the particles are not quantitatively enclosed in each partition, even if the same white is displayed, a difference occurs in the reflectance due to the influence of the thickness of the layer of the particles, resulting in an uneven display. It is difficult to put a small amount of 1 mg or less in the partition into the partition while quantifying it. Further, in the conventional example, a method has been described in which particles are scattered in the concave portions and excess particles are removed by friction with a blade. However, according to this method, only particles overflowing from inside the partition can be removed. In the case of displaying, the display speed and the contrast change depending on the rate at which particles are filled in the partition. At a filling factor of 80% or more, the display characteristics are good, but the movement of the particles is hindered by the presence of the particles, so that a problem that a high voltage is required arises. For this reason, a filling rate of 50% to 70% is preferable, but cannot be controlled by the method of scraping with a blade as described above. Furthermore, since the particles are as fine as several microns, once they adhere to the partition, it is difficult to peel them off. If the gap is 50 microns or less, the gap is greatly affected by the remaining particles.
[0013]
As a result, it is clear that it is difficult to handle the particles as they are, and it is considered that the quantitativeness by dispersing the particles in an organic solvent has a significant effect on display and production.
[0014]
As for the particles, the use of the white particles 4 and the black particles 5 makes it possible to display black and white in two colors. The black particles are made of a material which is easily charged negatively, and the white particles are made of a material which is easily charged positively. For example, a styrene-acrylic copolymer was prepared by adding a quaternary ammonium chloride for positive charging and a salicylic acid-based metal complex for negative charging. Alternatively, particles that have been treated with an organic substance using a silane coupling agent while improving the fluidity of the particles by previously adding silica or alumina to the outside of the particles can also be used. Although black and white colored particles are used, colorization is possible by using R (red), G (green), and B (blue) particles. Each of them may be subjected to a charging process. When the organic solvent quickly spreads in the partition, each particle also spreads in the partition (E).
[0015]
Since the organic solvent is as small as several microliters, it evaporates quickly. At this time, the mixed particles aggregate and adhere to the substrate (F). As a result, it was possible to solve the problem that the particles scattered when the particles were put into the partition as they were because the size of the particles was as small as several μm to several tens μm. Further, since ethanol or the like easily contains moisture, it can be vaporized in a short time by heating. If the gas is slowly vaporized, the particles form a large aggregate, and a large electric field is required for operation. Therefore, vaporization for a short time is preferable.
[0016]
Further, by attaching the transparent substrate 8 on which the electrodes 7 are formed to the partition 3 via an adhesive layer, an image display element can be formed (G). Since the image is viewed from the transparent substrate 8 side, it is necessary to use a transparent electrode for the electrode 7, and ITO was used by sputtering.
[0017]
When a voltage is applied to the upper and lower electrodes 2 and 7, the negatively charged black particles 5 move to the positive side, and the positively charged white particles 4 move to the negative side. Thereby, two-color display of black and white becomes possible. The particles may be subjected to a charging process in advance, or may be charged by applying an electric field as a charging process after being placed in a partition, or may be charged by friction and stirring of the particles by applying ultrasonic waves.
[0018]
(Embodiment 2)
In the first embodiment, a plurality of types of particles are mixed with an organic solvent. However, one type of particles is mixed with an organic solvent to vaporize, and further different types of particles are mixed with the organic solvent and poured over from above. It may be liquefied and vaporized. If this method is used, each particle can be more accurately distributed in the partition. If the material of each particle is different and there is a difference in specific gravity, the mixing ratio of the particles may change even if a fixed amount of liquid is injected.Injection for each particle increases the process but improves the accuracy. Was completed.
[0019]
(Embodiment 3)
In the first and second embodiments, the particles are fixed on the electrode 2 of the lower substrate 1. FIG. 2 shows a case where the white particles 4 and the black particles 5 are separately held on the upper and lower substrates 1 and 8. Was.
[0020]
A shows a diagram in which the electrodes 2, 7 and the partition 3 are formed on each of the substrates 1, 8, and the forming method is the same as that in the first embodiment. The substrate 1 does not need to be transparent, but may be the same as the transparent substrate 8.
[0021]
B represents a step of injecting the respective particles 4 and 5 into the partitions 3 of the upper and lower substrates 1 and 8. As described in the second embodiment, when the specific gravity of each particle is different, the quantitativeness is deteriorated. Furthermore, if the charging process is performed in advance, the particles are unlikely to move due to aggregation due to different types of charging due to mixing, and it is necessary to perform a separating process or increase the voltage required for moving. A problem arose. Therefore, the steps could be simplified by separately attaching the particles to the substrate and keeping the particles separate until the display process.
[0022]
C is a step of holding the particles 4 and 5 on the substrates 1 and 8 respectively, and a display element is manufactured by bonding the partitions 3 in D (E). In the step D, by using thin glass or resin for the substrate, a roll-to-roll method can be adopted, a large number of display elements can be manufactured at once, and cost reduction can be realized. When the particles did not adhere to the substrate, the particles scattered from the partition during the production, or the particles adhered to the partition, and a cleaning step was necessary or troublesome. By pouring the organic solvent in which the particles were mixed into each partition, the particles could be easily attached to the substrate, and the scattering of the particles could be prevented.
[0023]
(Embodiment 4)
In the first to third embodiments, the method of attaching particles to each substrate has been described. As a method of peeling the particles from the substrate, there is a method of applying an electric field to separate the particles from the substrate. However, it has been found that ultrasonic waves should be applied as a method of reliably separating the particles from the substrate. When 5 KHz ultrasonic waves are applied from the outside of the upper and lower substrates, the particles are separated from the substrate and vibrate. As a result, the particles collide with each other and with the partition and the electrode surface, and are rubbed and charged. When ultrasonic waves of 20 KHz were applied, the aggregation of the particles was broken and the particles were broken down into the original fine particles.
[0024]
When the particles aggregate, the voltage required to move between the electrodes increases. At the electrode spacing of 150 microns, when the particles were crushed to 5 microns, the particles could move at a voltage half as high as 150 V, compared to 300 V required when the particles were agglomerated. In the case of aggregated particles, the display was rough or uneven at the time of display, but when the particles were pulverized, a smooth uniform display was achieved. By applying ultrasonic waves, it was possible to lower the voltage and improve the display performance.
[0025]
(Embodiment 5)
In Embodiments 1 to 4, it has been found that when mixing particles in an organic solvent, the surface of the particles can be treated simultaneously by including a silane coupling agent. An amino-based coupling agent: NH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ³ is mixed with polyvinyl alcohol at 1%, and white particles having silica fine particles adhered to the surface are mixed and partitioned. When the solution was injected into the inside, the particles became positively charged and became less susceptible to humidity. This is presumably because the activity of the silica surface was reduced by the coupling agent to reduce the dependence on humidity. Towards black particles, halogenated compound-based _coupling agent mixed _{C l CH 2 CH 2 CH 2} Si (OCH 3) black particles ³ deposited a 1% polyvinyl alcohol silica fine particles on the surface was dissolved Then, when the liquid was injected into the partition, the particles became negatively charged and became less susceptible to humidity.
[0026]
As described above, the organic solvent for mixing the particles, the surface treatment agent for the particles, the coating agent for the electrode surface, and the like can be added and the particles can be dispensed into the partition at the same time, and the surface treatment of the particles and the surface treatment in the partition can be performed Therefore, it is possible to easily control the charging characteristics of the particles and to perform a surface treatment of a partition in which aggregation of the particles hardly occurs. This can contribute to cost reduction.
[0027]
【The invention's effect】
According to the present invention, in a device that displays an image by moving a particle by applying a voltage to the electrode in a configuration in which the particle group is sealed in a space formed by a pair of substrates and an electrode and a partition, the particle is converted to an organic solvent. After being dispersed and dropped into the partition to evaporate the organic solvent, the opposing substrate is adhered to the partition, whereby scattering of the particles can be prevented, and the particles can be accurately contained in the partition. Further, by adding a treating agent (such as a silane coupling agent) for treating the surface of the particles to the organic solvent, there is an advantage that the surface treatment of the particles and the surface treatment in the partition can be performed at the same time.
[0028]
Further, after the particles are confined, ultrasonic waves are applied to the display element to finely pulverize the particles, thereby enabling a smooth display at a low voltage.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a manufacturing process of an image display device. FIG. 2 is a schematic diagram of a manufacturing process of an image display device.
DESCRIPTION OF SYMBOLS 1 Substrate 2 Electrode 3 Partition 4 White particle 5 Black particle 6 Organic solvent 7 Electrode 8 Transparent substrate

Claims (7)

A method for manufacturing an apparatus for displaying an image by moving particles by applying a voltage to the electrodes in a configuration in which particles are sealed in a space formed by a pair of substrates and electrodes and a partition,
A method for manufacturing an image display device, comprising dispersing particles in an organic solvent, introducing the particles into a partition, vaporizing the organic solvent, and sealing the organic solvent with an opposing substrate. A method for manufacturing an apparatus for displaying an image by moving particles by applying a voltage to the electrodes in a configuration in which particles are sealed in a space formed by a pair of substrates and an electrode and a partition,
A method for manufacturing an image display device, comprising dispersing particles in an organic solvent, introducing the particles into partitions of each substrate, vaporizing the organic solvent, and sealing the organic solvent with an opposing substrate. A method for manufacturing an apparatus for displaying an image by moving particles by applying a voltage to the electrodes in a configuration in which particles are sealed in a space formed by a pair of substrates and an electrode and a partition,
An image characterized in that particles are dispersed in an organic solvent, introduced into a partition, the organic solvent is vaporized, sealed with a facing substrate, and particles are dispersed and charged by applying vibration to upper and lower substrates. A method for manufacturing a display device. A method for manufacturing an apparatus for displaying an image by moving particles by applying a voltage to the electrodes in a configuration in which particles are sealed in a space formed by a pair of substrates and an electrode and a partition,
Particles are dispersed in an organic solvent, introduced into a partition of each substrate, and the organic solvent is vaporized, then sealed with a facing substrate, and the particles are dispersed and charged by applying vibration to upper and lower substrates. Manufacturing method of an image display device. The method according to any one of claims 1 to 4, wherein a silane coupling agent is added to the organic solvent. 4. The method according to claim 1, wherein the particles sealed in the space are composed of particles of a plurality of colors, and are mixed with an organic solvent at the same time. 5. The method according to claim 2, wherein the particles sealed in the space are composed of particles of a plurality of colors, and the particles of the same color are dispersed in an organic solvent.

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