JP5541837B2 - Manufacturing method of particle movement type display device - Google Patents

Description

At least one is provided with a partition between transparent substrates, and a dispersion system in which charged or magnetized fine particles are dispersed in a liquid, liquid crystal or gas medium is filled in a cell constituted by both substrates and the partition, In the partition type particle movement display device in which the fine particles are moved by an electric field or a magnetic field to change the light reflectivity or light transmittance in the vertical direction of the cell, at least one of the substrates is a thin substrate that can be deformed into a convex shape. The two substrates are bonded at the periphery of the display device except for the dispersion inlet, and the dispersion is injected into the display from the dispersion inlet formed by the gap between the thin substrate and the partition wall. Then, the thin substrate is deformed into a convex shape by gravity acting on the injected dispersion system, a predetermined amount of the dispersion system is injected between the two substrates, the convex substrate is flattened, and then the injection port is sealed. Particle transfer characterized by stopping A manufacturing method of the type display device.

As a low power consumption display, a particle movement type display such as an electrophoretic display device, an electronic powder fluid display, and a magnetic display panel has been put into practical use. These display devices are roughly classified into a vertical electric field type and a horizontal electric field type. The former is a structure in which a particle dispersion system with different colors and charging polarities is sandwiched between a transparent electrode-attached substrate and an opposite electrode substrate, and either particle is placed on the transparent electrode side depending on the polarity of the applied electric field. The reflection color is changed by accumulating and hiding the other particle. When the dispersion medium is a liquid, the dispersion medium may be colored instead of one particle. In the latter case, light-shielding particles are dispersed in a transparent dispersion medium, and the particles are moved horizontally to the substrate and deposited on a large electrode to present a particle color and a small electrode to present the color of the lower substrate. Or the color of the lower substrate by changing the particle color in the dispersed state or the color of the lower substrate. In the case of a magnetic display panel, the principle of changing the reflection color or transmissivity is the same as that using an electric field, except that magnetic force is used to move particles vertically or horizontally.

Various configurations of the particle movement type display are shown in FIG. FIG. 1A shows a vertical electric field type in which fine particles having white and black colors and different charging polarities are dispersed in a transparent liquid or gas body. Either one of the drive electrode 6-1 and the common electrode 6-2 and the substrate are transparent, and particles can be separated as shown in the figure depending on the polarity of the voltage applied between both electrodes, and the reflected color can be changed. it can.

FIGS. 1B and 1C are examples of a horizontal electric field type display device, and a dispersion system in which light absorbing or light scattering fine particles are dispersed in a transparent liquid or a gas body is used. For example, a cell in which an AC voltage is applied between the drive electrode 6-1 and the common electrode 6-2 is opaque, and a cell in which particles are deposited on the electrode 6-1 is transparent. As shown in FIG. 2, the electrode configuration is a comb-shaped or spiral electrode pair facing each other. In the horizontal electric field type, it is not necessary to use a transparent electrode, but the electrode 6-2 in FIG. 1C may be transparent. FIG. 1D is a perspective view showing a configuration before providing the upper substrate of the panel of FIG. 1 (A) to 1 (C) are different in that the configuration of the electrodes is mainly different, but all are common in that the dispersion system is partitioned by the partition walls 20 to form a discontinuous phase. There are cases where the electrodes are on each other's substrate and cases where the electrodes are provided only on one substrate.

1A to 1C, the cell gap is usually 5 μm to 100 μm, and the distance between the electrodes is about 5 μm to 100 μm. In order to increase the aperture ratio of the display panel, it is desirable that the width of the partition wall 20 be as narrow as possible (about 1 μm to 50 μm), such as printing of insulating resin, resist etching process using light, electron beam, and X-ray as an exposure light source. Formed using. A plate-like electrode structure as shown in FIG. 1B can be formed by accumulating holes in a thick film resist that has been pierced using an X-ray called a LIGA process.

Although not shown in detail in the display device of FIGS. 1A to 1C, each cell (pixel) of the display panel can be driven by various driving methods such as static driving, passive matrix driving, and active matrix (AM) driving. Is adopted. For example, in the case of TFT-AM driving, an AM array made of a-Si, p-Si, an organic semiconductor, or the like is formed on the substrate 2 side, and the driving electrode of each cell is connected to the drain terminal of the TFT.

There is no problem in the particle movement display if the particle concentration is always kept constant in the pixel, but the particle concentration gradually becomes nonuniform in the display device due to the electric field, the flow of the dispersion medium, the specific gravity difference with the dispersion medium, etc. As a result, display unevenness occurs, and long-term reliability has been a problem. In order to solve this problem, practical use has progressed by providing a partition between the substrates and isolating the dispersion system in a grid pattern or encapsulating the dispersion system.

Encapsulation can solidify the display device and has features such as easy handling, sealing process, gap formation, etc., narrow partition wall width, and easy to realize high aperture ratio display. Technology that makes it difficult to completely eliminate light scattering because it is difficult to make the refractive index of the capsule wall and dispersion medium completely equal, and that it is easy to deteriorate the black level, and to produce high-performance capsules with uniform particle sizes There are also problems such as difficulty in driving, restrictions on the composition of the dispersion system, and drive voltage attenuation due to the capsule wall interposed between the electrodes.

The present invention proposes a novel dispersion injection and sealing method for a partition-type particle movement display that can easily realize a dispersion composition as designed and can effectively use an applied voltage.

As liquid crystal injection and sealing methods for widely used liquid crystal panels, (1) a large number of granular liquid crystals are uniformly dropped on the inner surface of one substrate of the liquid crystal panel and sandwiched between the other substrate under reduced pressure. Then, the gap between the two substrates is kept at a predetermined gap by pressurization, and the adhesive provided in the peripheral portion is cured in advance to fill and seal. Or (2) The substrate is bonded at the periphery, leaving the injection port, and the empty cell in which the predetermined gap is formed by the spacer is held in the vacuum chamber, and the injection port is immersed in the liquid crystal reservoir, and the vacuum chamber is enlarged. after filled more the liquid crystal cell is returned to atmospheric pressure, an inlet portion that has been widely used a method of sealing with resin.

Conventionally, a method as shown in FIG. 3A is used for the dispersion system injection and sealing method of the partition type particle movement type display. That is, this is a method in which the dispersion system 7 is supplied to the substrate 2 provided with electrodes, partition walls, etc., and the substrate 1 is sequentially covered with the partition walls. The adhesive provided on the spacer is fully cured to complete the sealing. In some cases, the substrates are bonded together by immersing both substrates in a dispersion system. In order to avoid contamination of the terminal take-out portions of the substrates 1 and 2, a method of protecting with a resin coat in advance and dissolving and removing the resin after completion of sealing is used. In the case of a liquid dispersion, the larger the panel is, the more difficult it is to manufacture the panel without mixing bubbles. In FIG. 3B, the substrate 1 is in the form of a film, and the roller 27 is rolled in the direction of the arrow to push out the dispersion system between the substrate 1 and the substrate 2, and the operation is more effective than the rigid substrates as shown in FIG. Although easier, there is still a high risk of air bubbles.

FIG. 4 shows the method of Document 1. A sealing composition precursor having a specific gravity smaller than that of the dispersion medium is mixed in the dispersion system 7, and the cell is filled with the dispersion system. Since the precursor that is not mixed with the dispersion medium is selected, the supernatant layer 26 is formed, and becomes a sealing layer 28 by being cured by UV irradiation or the like, thereby being sealed. The reinforcing or electrode-equipped substrate 1 is attached via an adhesive to complete the sealing panel. Although it is a smart method, the selection of materials such as the precursor material and sealing properties with the barrier ribs is the key point. In the vertical electric field type, the voltage attenuation is also caused by the sealing layer 28 and the adhesive resin interposed between the dispersion layer and the electrode. Becomes an issue.
Special table 2005-509690

In the particle movement type display, in order to ensure the uniformity of the concentration of particles in the display surface, the disperse system needs to be confined in a cell formed by both substrates and partition walls to be a discontinuous phase. Therefore, it has been impossible or difficult to apply a method of injecting a dispersion system with a pressure difference into an empty cell whose interior is evacuated as used in a liquid crystal panel that does not require a partition wall.

In order to solve the above-mentioned problem, at least one of the substrates according to the present invention is a thin substrate that can be deformed into a convex shape, and both the substrates are bonded to each other at the periphery of the display device except for the dispersion inlet portion. A manufacturing method of a particle movement type display device, wherein the thin substrate is filled with the dispersion system in a convex state, the convex substrate is flattened, and then the injection port is sealed. It is about the law.

In general, there are three types of particle transfer type display panels, G / G type, F / G type, and F / F type, depending on the types of substrates 1 and 2. G means a rigid substrate, such as a thick glass, a thick and hard plastic substrate, a thick metal plate, or a silicon substrate. F means film and / or flexible, and means plastic film, thin glass sheet, thin metal sheet, paper and the like. In any case, at least one is transparent. The substrate 2 may be a silicon substrate on which an AM array made of FET elements is formed, or may be an AM array made of a-Si or p-Si formed on a stainless steel sheet. The particle movement type display is applied to a wide range of sizes from a size of about 1 inch used for a projection type light valve to a size exceeding 100 inches. The F / F type is useful as a so-called sheet display or flexible electronic paper display. Accordingly, there has been a demand for a dispersion filling and sealing method excellent in mass productivity that can be applied to panels of all forms and sizes.

This is an injection and sealing method that enables the G / G type panel which was most difficult in the present application, and includes a substrate 2 provided with electrodes, partition walls, spacers, etc. as shown in a sectional view in FIG. A thin substrate 6 having a film shape and having an electrode on the inner surface or without an electrode is previously bonded to a panel peripheral spacer 9 part except for 10 parts of the dispersion injection port. Next, for example, if the dispersion system 7 is injected from the injection port 10 through a thin pipe from the dispersion system supply tank, the thin substrate is slightly caused by the dispersion outflow pressure, the pressure due to gravity applied to the injected dispersion system, and the elastic deformation of the thin substrate 6. As a result, a slight gap through which the dispersion system can pass is formed between the thin substrate 6 and the partition wall 20. As a result, the dispersion system can be filled between the substrates as shown in FIG. As a prototype, an injection needle may be inserted into the injection port and injected using a syringe. Since the amount of dispersion to be filled in the panel when the distance between the substrates is almost parallel is almost determined by the panel size, cell gap, cell area and number, etc., the injection amount should be determined in consideration of panel variation. . Next, when the thin substrate 6 and the substrate 2 are pressurized using a roller 27 or the like so as to form a substantially uniform gap and the dispersion port is slightly overflowed, the injection port is sealed with a UV curing adhesive or the like. Is injected into the panel (FIG. 5C). If the thin substrate 6 is concerned in terms of strength or reliability, it may be reinforced by attaching the rigid or higher strength film substrate 1 to the thin substrate 6 using an adhesive (FIG. 5D). . Thus, a G / G type panel can be formed.

Similarly, when the dispersion medium is a gas body, it may be injected at a fluid pressure in a gas dispersion state. However, the fine particles are uniformly dispersed in a liquid, injected and flattened in a liquid dispersion state, and the panel before sealing. Can be filled in the gas dispersion system by holding in a vacuum chamber and evaporating the liquid through the inlet and then sealing.

The thickness of the thin substrate will vary greatly depending on the material and panel size, if the panel is large is sufficiently applicable even thin glass substrate. The particle size in the dispersion is usually 0.1 μm to 5 μm, and if a gap of several tens of μm can be formed as a gap between the substrate 6 and the partition wall 20, the dispersion can be filled in all cells. State high elastic restoring force material to prevent this from tends to wrinkle in the the elastic deformation as a film material does not return to the original FIG. 5 (C), the Ru der should be selected thickness. It is not preferable that the gap is excessively widened when the dispersion is injected, and the minimum gap necessary for the dispersion to sufficiently spread in the panel should be obtained. The gap can be adjusted by the inclination angle of the panel and the dispersion supply rate (gram / second). The pipe inserted into the inlet should be as thin as possible so as to reduce the deformation of the substrate 6. In FIG. 5E, although there is one injection port, a plurality of injection ports may of course be provided in order to improve the uniformity and speed of introduction of the dispersion system.

When using a liquid dispersion system, it is necessary to strictly avoid bubbles remaining in the panel. In the process of FIG. 5, the empty panel (FIG. 5 (A)) is put in a vacuum chamber, the inlet is made to be ventilated with wedge, the pressure is reduced, the gas in the panel is exhausted sufficiently, and then under vacuum Injecting the dispersion helps to prevent residual bubbles and to quickly fill the dispersion. In particular, in the panel structure of FIG. 1B, degassing is extremely effective because partition walls and electrodes are erected, and gas tends to remain and hinder the fluidity of the dispersion system.

The F / F type panel can be filled with a dispersion system quite easily in the same manner, and the F / G type is also the same.

In the above description, the thin substrate 6 and the substrate 2 are only bonded by the peripheral spacer portion, and the upper surface of the partition wall and the substrate 6 are not bonded. When the dispersion system is a liquid or liquid crystal, the substrate 6 is not easily peeled off due to the surface tension acting between the dispersion system and the substrate, but the panel gap is more uniform, air bubbles are prevented, and the panel is kept vertical for a long time. In this case, it is desirable that the partition wall and the substrate 6 are similarly bonded to the substrate 2 in order to prevent a downward swelling phenomenon due to gravity. In order to form such a panel, a UV curable resin or the like is thinly applied and temporarily cured on the upper surface of the partition wall in advance, and after the dispersion system injection and thin substrate flattening or sealing (FIG. 5C), the substrate 6 is obtained. The partition wall portion may be irradiated with UV to pass through the main curing between the substrate 6 and the partition wall upper surface. Of course, a material that does not dissolve in the pre-cured state and the dispersion after the main curing is selected as the adhesive material.

Compared with liquid crystal display devices using birefringence, the particle movement type display device has a higher tolerance for gap uniformity against display unevenness and response speed unevenness, but does not use the birefringence phenomenon, so a birefringent film can also be used. The feature is that the degree of freedom of film selection is extremely high.

Film materials include vinyl polyethylene, polyvinyl chloride, polyvinylidene chloride, polypropylene, polystyrene, fluororesin, polyamide polycarbonate, polyethylene terephthalate, polyamide nylon, heat-resistant engineering plastic, polyimide, poly Various materials such as sulfone, polyether sulfone, polyphenylene sulfide, polyether ketone, and polyetherimide can be used.

In general, a polymer film is more permeable to gas than glass. In order to improve the reliability of the film panel, it is effective to provide a gas barrier layer on the film surface. As the gas barrier layer, it is known that thin films such as silicon oxide and silicon nitride, and laminated films of these films and organic films such as vinyl alcohol-containing polymers are known.

In FIGS. 1A to 1C, an example in which an electric field is used for movement of fine particles has been described. However, if the fine particles have magnetism, magnetic force can be used for particle accumulation and dispersion. The dispersion injection and sealing method shown in 5 can be employed.

In FIG. 5, the dispersion filling and sealing method of a single panel has been described. However, the F / F type panel has an advantage that it can be easily manufactured by roll-to-roll. Using a roll-like film finished in a single-piece or multi-piece form as shown in FIG. 1D on the film substrate 2 and a roll-like film of the thin substrate 6, as in FIG. If a panel is continuously formed with a roll, it becomes a manufacturing method with extremely excellent mass productivity.

The dispersion injection and sealing method of the present invention can be applied to a wide range of sizes from 1 inch or less to over 100 inches by selecting the material and thickness of the thin substrate, and there is little panel contamination at the time of injection and dispersion. It is a manufacturing method with low system loss and excellent mass productivity. It can be used for all panel configurations of G / G type, F / G type, and F / F type, and its application range has been expanded.

(A)-(C) is a cross-sectional view which shows the principle of the particle movement type display apparatus used for manufacture of this invention, (D) is a fragmentary perspective view of (C). Is a front view of electrodes used in the horizontal electric field particle movement type display device of FIGS. (A), (B) is a cross-sectional view showing a conventional method of filling a particle transfer type display device with a dispersion system FIG. 4 is a cross-sectional view showing another conventional method of filling a particle transfer type display device with a dispersion system. FIG. 3 is a view showing a manufacturing method of the present invention in which a partition type particle movement type display device is filled with a dispersion and sealed.

DESCRIPTION OF SYMBOLS 1 Upper substrate 2 Lower substrate 5 Fine particle 6 Thin substrate 6-1 Drive electrode 6-2 Common electrode 7 Dispersion system 8 Cell 9 Spacer 10 Inlet 20 Bulkhead 22 Dispersion medium 24 Panel 25 Seal 26 Supernatant layer 27 Roller 28 Sealing layer

Claims (1)

At least one is provided with a partition between transparent substrates, and a dispersion system in which charged or magnetized fine particles are dispersed in a liquid, liquid crystal or gas medium is filled in a cell constituted by both substrates and the partition, In the partition type particle movement display device in which the fine particles are moved by an electric field or a magnetic field to change the light reflectivity or light transmittance in the vertical direction of the cell, at least one of the substrates is a thin substrate that can be deformed into a convex shape. The two substrates are bonded at the periphery of the display device except for the dispersion inlet, and the dispersion is injected into the display from the dispersion inlet formed by the gap between the thin substrate and the partition wall. Then, the thin substrate is deformed into a convex shape by gravity acting on the injected dispersion system, a predetermined amount of the dispersion system is injected between the two substrates, the convex substrate is flattened, and then the injection port is sealed. Particle transfer characterized by stopping Process for the preparation of type display device