JP4191464B2 - Manufacturing method of image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an image display device, and more particularly, to a method for manufacturing a reversible image display device (image display medium) capable of repeatedly performing image display by utilizing particle movement by Coulomb force. It is.
[0002]
In recent years, with the heightening of environmental awareness such as paperlessness, much research has been conducted on electronic paper displays that can display desired images on a display board using electric power and can be rewritten. ing. Particularly famous in this electronic paper technology is a liquid phase type such as an electrophoretic type (see, for example, Non-Patent Document 1), a thermal rewritable type, etc. However, in the liquid phase type, since particles migrate in the liquid, Since there is a problem that the response speed becomes slow due to viscous resistance, recently, a dry type having a structure in which insulating color particles are sealed between opposing substrates as shown in FIG. 3 has been attracting attention.
[0003]
[Non-Patent Document 1]
趙 Kuniori and three others, “New Toner Display Device (I)”, July 21, 1999, Annual Meeting of the Imaging Society of Japan (83 times in total) “Japan Hardcopy'99”, p.249-252
[0004]
[Problems to be solved by the invention]
However, in the dry type, the manufacturing method is not generally established, and a method for enclosing the particles (group), which is a particularly important point, between the substrates uniformly, uniformly and smoothly is hardly established. Here, if the encapsulation of the particles does not satisfy the above conditions, problems such as uneven color, missing images, uneven image response speed due to non-uniform gaps between substrates, and increased drive voltage will occur.
[0005]
Examples of the method for enclosing the particles between the substrates include, for example, a roll coater coating method in which the powder is stretched on the substrate, or the powder is suspended in the air by stirring, air blowing, etc., and the substrate is passed through it. A particle dipping method for applying particles onto a substrate is conceivable. However, in the roll coater application method, the particles are difficult to adhere to the substrate, so that insufficient filling amount (coating amount) and uneven concentration tend to occur. In the particle immersion method, the particles do not easily adhere to the substrate, so that the shortage of the filling amount is likely to occur. In addition, the particles are not fixed firmly to the substrate. However, scattering and deviation of the laminated particles are likely to occur due to wind pressure, and neither method is sufficient.
[0006]
In view of the above, an object of the present invention is to provide a method for manufacturing an image display device capable of uniformly, uniformly and smoothly encapsulating two or more kinds of powders between opposing substrates, and more specifically, one side. Alternatively, a method of manufacturing an image display device in which powder is evenly and smoothly applied on both substrates and the particles are not scattered or the powder layer is not displaced even when the two substrates are superimposed. The purpose is to provide.
[0007]
[Means for Solving the Problems]
The manufacturing method of the image display device of the present invention that achieves the above-described object is the method comprising two or more kinds of particles having different colors, which are encapsulated between two substrates facing each other and having at least one light transmission property. An electric field is applied from the electrode pair provided between the two substrates to particles in which two types are combined and two types of each set have different triboelectric charging characteristics. When manufacturing an image display device that displays an image by flying and moving the two types of particles, the two types of particles in each set are positively triboelectrically charged by electrostatic powder coating. A positive charge is applied to the particles and a negative charge is applied to the negatively triboelectrically charged particles and applied onto at least one of the two substrates, and then enclosed between the two substrates. It is characterized by .
[0008]
According to the manufacturing method of the image display device of the present invention, an electric adhesion force is generated between the particles as the powder and the substrate by the electrostatic powder coating method. Since it can be uniformly coated on the substrate and the particle layer is fixed by the electro-image force between the substrate after coating, the scattering and deviation of particles that are likely to occur when the substrates are superimposed are prevented. Can be prevented.
[0009]
Here, the electrostatic powder coating method refers to a coating method in which a solid powder coating is applied to the surface of an object using static electricity. According to this coating method, the surface of the object is coated. A uniform and dense powder coating layer can be formed by electric image force. In the electrostatic powder coating method, a powder coating is charged and discharged from an electrostatic spray gun, and it is caused to fly by aerodynamic force and electric field force to adhere to an object to be coated by electric image force. And air is blown from the bottom plate of the perforated plate provided with the electrode to form a fluidized layer of powder coating and a floating layer of charged powder particles above the fluidized tank, and the covered layer is covered with the floating layer. There is an electrostatic fluidized dipping method in which a powder coating material is attached by electric image force through a coating. In the electrostatic spray method, the powder discharged from the electrostatic spray gun is charged by a corona generated at the tip of the spray gun, and the spray gun is charged to the powder discharged from the electrostatic spray gun. There are a tribo charging method in which charging is performed by friction with an electrode inside, and a hybrid charging method in which they are combined.
[0010]
In the manufacturing method of the image display device of the present invention, the particles are applied on the substrate instead of the powder paint by the electrostatic powder coating method. Any of these may be used.
[0011]
By the way, in the image display device of the present invention, two or more kinds of particles having different colors, each of which is a set of two kinds, and each set of particles in which two kinds of each set have different triboelectric charging characteristics. Since the image display is controlled by applying a voltage by making the frictional charging characteristics of the two types of particles different and using the charge amount of these particles, the image display is not sufficient. It becomes difficult to control. For example, if an operation such as reversal is repeated several times, frictional charging occurs due to collision between two types of particles, and the amount of charged particles becomes sufficient, but at the beginning of use of the apparatus where there is no collision between particles. In general, it is difficult to keep particles sufficiently charged.
[0012]
In this regard, according to the method of manufacturing an image display device of the present invention, the electrostatic frictional coating method allows positive tribocharging of two types of particles in each set of two or more types of particles having different colors. A positive charge is applied to the particles, and a negative charge is applied to the negative triboelectrically charged particles and applied onto at least one of the two substrates, and then sealed between the two substrates. Therefore, a sufficient initial charge amount can be maintained in the particles.
[0013]
The two or more kinds of particles may be mixed and applied. However, since the triboelectric charging characteristics of the two kinds of particles in each group are opposite characteristics, if mixed, they are aggregated by Coulomb force before application. Since there is a possibility, it is preferable to apply two types of particles in each group one by one. The two or more types of particles may be applied to only one of the two substrates or to both of the substrates. First, two or more types of particles may be applied to only one of the two substrates. After that, it is preferable to enclose the substrate with the other substrate to which the particles are not applied at all to enclose the particles, since the manufacturing process can be facilitated.
[0014]
Then, as described above, the two kinds of particles in each set are applied and laminated only on one of the two substrates by electrostatic powder coating, and after the two powders are formed, When encapsulating between the substrates, it is preferable that the potential applied to the first applied particles be lower than the potential applied to the particles that are then applied and stacked on the layer of the first applied particles.
[0015]
This is because if the charge amount of the first layer particles is too large, the image power between the substrate surface becomes too strong, and even if an electric field is applied to the first layer particles, the adhesion force is too strong. On the other hand, since the first layer already exists for the next layer, even if the amount of charge at the time of application is large, the adhesion force to the substrate surface is low. On the contrary, if the amount of charge at the time of application is small, the adhesion force to the substrate surface is too weak, and it is easy to cause scattering of particles and displacement of the particle layer when the other substrate is stacked. Because.
[0016]
However, when lamination is performed by the above-described method, aggregation of particles may occur due to Coulomb force between the particles, and uniformity and smoothness may be lost. Two types of particles are preferably applied on the two substrates by electrostatic powder coating, one for each substrate, and the potential applied to the particles during the application is preferably 40 KV or less. In this way, it is possible to prevent the aggregation of particles, and in addition to the excessive charge amount of the particles, the electric image force between the substrate surface becomes too strong and the particles are applied even if an electric field is applied to the particles. It is also possible to prevent the substrate from moving from the surface.
[0017]
In the image display device manufacturing method of the present invention, it is preferable that a spacer for forming a predetermined gap between the two substrates is held on at least one of the two substrates. In this way, a predetermined gap can be easily secured between the two substrates.
[0018]
Furthermore, in the method for manufacturing an image display device of the present invention, it is preferable that a partition wall for partitioning cells of the cell group is provided on at least one of the two substrates. In this way, a partition wall for partitioning the cells of the cell group between the two substrates can be easily secured.
[0019]
Furthermore, in the method for producing an image display device of the present invention, it is preferable that the average particle diameter of the particles is 0.1 μm or more and 50 μm or less, and the electrodes constituting the electrode pair are formed on the inner surfaces of the two substrates. Are preferably provided so as to face each other, and at least one of the two substrates is preferably formed of transparent electrode glass or transparent electrode resin, and the particles are enclosed between the two substrates. Is preferably performed in an environment with a relative humidity of 60% RH or less.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a method for manufacturing an image display device of the present invention will be described in detail. In the embodiment described below, as shown in FIG. 1, two types of particles having different colors and triboelectric charging characteristics, for example, white particles 3 having positive triboelectric charging properties and negative triboelectric charging properties are provided between two substrates 1 and 2. Are divided into a plurality of cells in a matrix arrangement by a grid spacer 5 having a height of 50 μm that also functions as a partition wall interposed between the substrates. The image forming apparatus D is a method for manufacturing a dry image display device D in which a predetermined gap is provided between the substrates 1 and 2 with the spacer 5, but the present invention is limited to this embodiment. It is not something.
[0021]
In this embodiment, as the transparent substrate 1 and the counter substrate 2 as two substrates, both use a conductive transparent glass substrate in which ITO (indium tin oxide) is vapor-deposited on a glass substrate, and only on one substrate 2, A spacer 5 that also functions as a partition wall for a plurality of cells was provided by an ink jet method. In addition, as the positive triboelectrically white particles 3, titanium oxide is used as a white pigment and a quaternary ammonium salt compound is used as a charge control agent to produce polymer particles of styrene acrylic resin (spherical particles having an average particle diameter of 8 μm). As the negative triboelectrically chargeable black particles 4, black polymerized toner for electrophotography (spherical particles having an average particle diameter of 8 μm) was used. When the white particles 3 having positive triboelectric chargeability and the black particles 4 having negative triboelectric chargeability are laminated on the substrate and sealed between the substrates, specifically, as in the following embodiments, Went.
[0022]
【Example】
Example 1
In Example 1, particles are applied on a substrate using a corona electrostatic powder coating apparatus as shown in FIG. 2 and the application method is applied only to the substrate 1 without the spacer 5. The white particles 3 and the black particles 4 were applied in this order. In the figure, reference numeral 6 denotes a corona electrostatic spray gun, 7 is a conductive plate which is grounded and supports the substrate, 8 is a supply device of particles as powder, and 9 is a power source. That is, in Example 1, as shown in FIG. 2, a corona-type electrostatic spray gun 6 applies a 20 kV corona voltage to the white particles 3 to apply a first white particle 3 layer on the substrate 1. Next, a corona voltage of −50 kV was applied to the black particles 4 to laminate a second layer of black particles 4 on the first layer.
[0023]
By superposing the other substrate 2 provided with the spacer 5 on the substrate 1 on which the particle layer is laminated, and fixing the adhesion surfaces of the two substrates 1 and 2 with resin from the side, The image display device D in which the particles 3 and 4 were enclosed could be manufactured. When a reverse image of the entire surface was produced by applying an AC voltage of 100 V and a frequency of 2 Hz to this image display device D, a clean and uniform reverse image was confirmed after 3 seconds.
[0024]
Example 2
In Example 2, particles are coated on a substrate using a corona electrostatic powder coating apparatus as shown in FIG. 2, and the coating method is such that only white particles 3 are applied to one substrate 1 and the other substrate. In the method 2, only the black particles 4 were applied. That is, in Example 2, the corona-type electrostatic spray gun 6 applied a white corona voltage of 20 kV to the white particles 3 to apply the white particles 3 on the one substrate 1 without the spacer 5, The black particles 4 were applied to the other substrate 2 provided with the spacers 5 by applying a corona voltage of −20 kV to the black particles 4.
[0025]
Images in which two types of particles 3 and 4 are enclosed are obtained by superimposing the substrates 1 and 2 on which these particle layers are laminated and solidifying the adhesive surfaces of the two substrates 1 and 2 with resin from the side. Display device D could be manufactured. When a reverse image was produced on the entire surface by applying an AC voltage of 100 V and a frequency of 2 Hz to the image display device D, a clean and uniform reverse image was confirmed after 3 seconds.
[0026]
【The invention's effect】
As is clear from the above description, according to the method for manufacturing an image display device of the present invention, an electric adhesion force is generated between the particles and the substrate by the electrostatic powder coating method. The amount of particles can be uniformly applied on the substrate, and the particle layer is fixed by the electro-image force between the substrate and the particles even after application. Can be prevented.
[0027]
According to the method for manufacturing an image display device of the present invention, the electrostatic powder coating method is applied to positively triboelectrically charged particles among the two types of particles in each set of two or more types of particles having different colors. And applying a negative charge to the negatively triboelectrically charged particles and applying it on at least one of the two substrates, and then encapsulating between the two substrates. A sufficient initial charge amount can be maintained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a dry image display device manufactured by an embodiment of a method for manufacturing an image display device of the present invention.
FIG. 2 is an explanatory diagram showing an example of an electrostatic powder coating method used in the manufacturing method of the embodiment.
FIG. 3 is an explanatory view illustrating a conventionally known dry image display device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Opposite substrate 3 White particle 4 Black particle 5 Spacer 6 Corona type electrostatic spray gun 7 Conductive plate 8 Particle supply device 9 Power supply

Claims (9)

Two or more kinds of particles having different colors, which are encapsulated between two substrates facing each other and at least one of which is light transmissive, are grouped into two types, and two types of each group are An image display device that displays an image by applying an electric field to the particles having different triboelectric charging characteristics from an electrode pair provided between the two substrates and causing the two types of particles in each group to fly and move In manufacturing
Applying a positive charge to the positive triboelectrically charged particles and applying a negative charge to the negative triboelectrically charged particles among the two types of particles by the electrostatic powder coating method. And after apply | coating on at least one board | substrate among the said 2 board | substrates, it seals between the said 2 board | substrates, The manufacturing method of the image display apparatus characterized by the above-mentioned. The two kinds of particles in each set are applied and laminated only on one of the two substrates by electrostatic powder coating method, and after being formed into a powder layer, between the two substrates. 2. The method of claim 1, wherein, when encapsulating, the potential applied to the first applied particle is set lower than the potential applied to the particle that is subsequently applied and laminated on the layer of the first applied particle. Manufacturing method of the image display apparatus. When applying two types of particles of each set to each of the two substrates by electrostatic powder coating method, the potential applied to the particles is set to 40 KV or less. A method for manufacturing the image display device according to claim 1. The image according to any one of claims 1 to 3, wherein a spacer for forming a predetermined gap between the two substrates is held on at least one of the two substrates. Manufacturing method of display device. 5. The method for manufacturing an image display device according to claim 1, wherein a partition wall for partitioning cells of the cell group is provided on at least one of the two substrates. . The method for manufacturing an image display device according to claim 1, wherein an average particle diameter of the particles is 0.1 μm or more and 50 μm or less. 7. The method for manufacturing an image display device according to claim 1, wherein the electrodes constituting the electrode pair are provided on the inner surfaces of the two substrates so as to face each other. 8. The method for manufacturing an image display device according to claim 1, wherein at least one of the two substrates is formed of transparent electrode glass or transparent electrode resin. 9. The method for manufacturing an image display device according to claim 1, wherein the particles are sealed between the two substrates in an environment having a relative humidity of 60% RH or less.

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