Method for manufacturing image display cell

Abstract

To provide an image display cell manufacturing method capable of suppressing the deformation of substrates constituting an image display cell.SOLUTION: An image display cell manufacturing method includes: a first step of sticking a pixel substrate 101 and a counter substrate 105 together through a frame-like seal material 102 in which an opening 107 is formed; a second step of pressurizing at least one of the pixel substrate 101 and the counter substrate 105 toward the other from the outside to squash the seal material 102 between the pixel substrate 101 and the counter substrate 105 and close the opening 107 with the squashed seal material 102; a third step of releasing the pressurization to decrease the internal pressure of a cell Gap108 and deform at least one of the pixel substrate 101 and the counter substrate 105 so as to approach the other; and a fourth step of curing the seal material 102 to increase the internal pressure of the cell Gap108 and make the pixel substrate 101 and the counter substrate 105 in a flat state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an image display cell. [Background technology]

[0002] In recent years, a wide variety of image display cells, such as organic EL elements, liquid crystal elements, DLP (DMD) elements, etc., have been introduced into the market.

[0003] In many image display cells, a pixel pattern is formed on a glass or silicon substrate. In organic EL elements, images are displayed by the light emission of the light-emitting elements that make up the pixel pattern themselves, while in liquid crystal elements and DLP elements, images are displayed by controlling external light with the pixel pattern.

[0004] However, the pixel pattern formed on the substrate is susceptible to destruction due to external stress and deterioration due to the environment, for example, humidity. Therefore, a glass substrate or the like (hereinafter, "opposing substrate") is usually placed on the substrate on which the pixel pattern is formed (hereinafter, "pixel substrate") to protect and seal the pixel pattern.

[0005] At this time, in order to prevent the pixel pattern from being scratched by the opposing substrate touching the pixel pattern, the opposing substrate must be placed on the pixel substrate with a certain distance in between, so a resin material containing spacers for controlling the distance (hereinafter, a sealant) is usually placed on the pixel substrate except for the pixel pattern, and the pixel substrate and opposing substrate are bonded together using this sealant. However, the spacers are not essential and may be omitted.

[0006] Furthermore, since the pixel pattern of the pixel substrate needs to be sealed to prevent the effects of humidity, etc., a sealant is usually placed in a frame shape around the pixel pattern and the space surrounded by the sealant is sealed to prevent moisture from entering the area where the pixel pattern is formed (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2002-25764 A [Patent Document 2] JP 2005-228493 A Summary of the Invention [Problem to be solved by the invention]

[0008] When creating an image display cell with the above-mentioned structure, a sealant is placed on the pixel substrate and the counter substrate is bonded to the pixel substrate, and gas such as air may remain in the sealed space (hereinafter, cell gap) surrounded by the pixel substrate, counter substrate, and sealant. This remaining gas may act to expand the cell gap, causing deformation (distortion, etc.) of the pixel substrate and counter substrate.

[0009] When such deformation occurs in the pixel substrate or the counter substrate, the optical path length of the light incident on the image display cell or the light emitted from the image display cell changes partially, resulting in a significant impairment of the image display quality.

[0010] The present invention has been made in view of the above problems, and has an object to provide a method for manufacturing an image display cell that is capable of suppressing deformation of a substrate that constitutes the image display cell. [Means for solving the problem]

[0011] A method for manufacturing an image display cell having a pixel substrate and a counter substrate, the method comprising: a first step of bonding the pixel substrate and the counter substrate together via a frame-shaped sealing material having a gap formed therein; a second step of applying pressure to at least one of the pixel substrate and the counter substrate from the outside toward the other to crush the sealing material between the pixel substrate and the counter substrate and close the gap with the crushed sealing material; a third step of releasing the pressure to reduce an internal pressure in a space surrounded by the pixel substrate, the counter substrate, and the sealing material, thereby deforming at least one of the pixel substrate and the counter substrate so as to approach the other; and a fourth step of hardening the sealing material to increase the internal pressure in the space and flatten the pixel substrate and the counter substrate.

[0012] The method for manufacturing an image display cell may further comprise increasing the internal pressure of the space in the fourth step to eliminate a pressure difference between the internal pressure and the external pressure of the space. Effect of the Invention

[0013] According to the present invention, it is possible to provide a manufacturing method for an image display cell that is capable of suppressing deformation of a substrate that constitutes the image display cell. [Brief description of the drawings]

[0014] [Figure 1] 1A is a top view and FIG. 1B is a cross-sectional view along the line AA, showing a state in which a sealant is disposed on a pixel substrate of an image display cell according to an embodiment of the present invention. [Diagram 2] 1A is a top view and FIG. 1B is an AA cross-sectional view showing a state during the process of attaching a counter substrate to a pixel substrate of an image display cell according to an embodiment of the present invention. [Diagram 3] 1A is a top view and FIG. 1B is an AA cross-sectional view showing a state after the operation of bonding a counter substrate to a pixel substrate of an image display cell according to an embodiment of the present invention. [Figure 4]1A is a top view showing a state after the pressure applied to the counter substrate of the image display cell according to the embodiment of the present invention has been released, and FIG. 1B is a cross-sectional view taken along the line AA. [Diagram 5] 1A and 1B are a top view and a cross-sectional view along the line AA, showing a state after a sealant of an image display cell according to an embodiment of the present invention has been cured. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] FIG. 1 is a top view (a) and an AA cross-sectional view (b) showing a state in which a sealant is disposed on a pixel substrate of an image display cell according to an embodiment of the present invention. FIG. 2 is a top view (a) and an AA cross-sectional view (b) showing a state in the middle of the work of bonding a counter substrate to a pixel substrate of an image display cell according to an embodiment of the present invention. FIG. 3 is a top view (a) and an AA cross-sectional view (b) showing a state in which the work of bonding a counter substrate to a pixel substrate of an image display cell according to an embodiment of the present invention has been completed. FIG. 4 is a top view (a) and an AA cross-sectional view (b) showing a state after the pressure applied to the counter substrate of an image display cell according to an embodiment of the present invention is released. FIG. 5 is a top view (a) and an AA cross-sectional view (b) showing a state after the sealant of an image display cell according to an embodiment of the present invention has been hardened. Hereinafter, the embodiments of the present invention will be described with reference to these drawings.

[0016] In this embodiment, the image display cell is an organic EL element or a DLP element. In this embodiment, the image display cell is manufactured by a manufacturing process including the following steps S1 to S5.

[0017] <s1> As shown in Fig. 1, a sealant 102 is arranged in a frame shape around a pixel pattern 103 formed on a pixel substrate 101. The method for arranging the sealant 102 may be appropriately selected from coating with a dispenser, screen printing, and the like. At this time, a gap (opening) 107 for releasing air from the space surrounded by the sealant 102 is provided in a part of the sealant 102. An electrode terminal 104 electrically connected to the pixel pattern 103 is formed in advance on the surface of the pixel substrate 101.

[0018] The width D of the gap 107 is set to a distance such that when the bonding of the opposing substrate 105 is completed in step S3 described below, the gap 107 is completely filled with the sealant 102. For example, this distance is determined in advance by calculation or experimentation as to the distance that the sealant 102 is compressed and stretched from the start to the end of bonding of the opposing substrate 105, and the width D is set to a distance equal to or less than twice the stretched distance.

[0019] <s2> Next, as shown in FIG. 2, in an atmospheric pressure environment filled with air, the counter substrate 105 is bonded to the pixel substrate 101 via the sealant 102, and the counter substrate 105 is gradually pressurized toward the pixel substrate 101 with a constant pressure from the outside. At this time, the pixel substrate 101 is placed on, for example, a pressure stage (not shown), and the counter substrate 105 is pressurized by, for example, a pressure plate (not shown). As the pressure on the counter substrate 105 progresses, the sealant 102 is pressed by the counter substrate 105 and gradually stretches in the width direction, and accordingly, the air 106 in the cell gap 108 is gradually pushed out of the cell gap 108 through the gap 107, and at the same time, the gap 107 is gradually filled with the stretched sealant 102. Note that during this process, the gap 107 is not completely filled with the sealant 102, so the internal pressure of the cell gap 108 is kept equal to the external pressure.

[0020] <s3> 3, the process of step S2 described above is continued, and this process is terminated when the gap 107 is completely filled with the sealant 102. As a result, the gap 107 is completely blocked by the sealant 102, and the cell gap 108 is sealed. At this point, the spacer (not shown) mixed in the sealant 102 is sandwiched between the pixel substrate 101 and the counter substrate 105 to such an extent that it does not deform, or to such an extent that it deforms slightly.

[0021] <s4> Next, as shown in Fig. 4, the pressure applied to the counter substrate 105 is released. As a result, the sealant 102 is released from the pressure applied by the counter substrate 105, and the sealant 102 is pulled back slightly toward the center in the width direction by the restoring force due to the elasticity of the sealant 102 itself and the restoring force due to the elasticity of the spacer mixed in the sealant 102, and the counter substrate 105 is slightly separated from the pixel substrate 101, and the volume of the cell gap 108 temporarily increases. However, since the gap 107 is already filled with the sealant 102 at this point, no new air is supplied from the outside to the inside of the cell gap 108, and as a result, the internal pressure of the cell gap 108 becomes lower than the external pressure, and a pressure difference occurs between the internal pressure of the cell gap 108 and the external pressure. Then, due to this pressure difference, the pixel substrate 101 and the counter substrate 105 are curved in a direction approaching each other with the sealant 102 as a fulcrum, and the cell gap 108 is curved in a concave shape toward the center in the thickness direction. In this embodiment, both the pixel substrate 101 and the counter substrate 105 are curved, but there may be cases where only one of the pixel substrate 101 and the counter substrate 105 is curved toward the other.

[0022] <s5> Next, as shown in Fig. 5, the sealant 102 is cured. The method of curing the sealant 102 is appropriately selected depending on the material of the sealant 102. For example, when the sealant 102 is an ultraviolet curable resin, the sealant 102 is cured by irradiating the sealant 102 with ultraviolet light. At this time, the sealant 102 expands due to heat (for example, heat generated by ultraviolet light irradiation) generated when curing the sealant 102 and simultaneously causes curing shrinkage, and the combined action of these causes the volume of the cell gap 108 to decrease overall, or a part of the components of the sealant 102 vaporizes and gas is released from the sealant 102. As a result, the internal pressure of the cell gap 108 increases, the pressure difference between the internal pressure of the cell gap 108 and the external pressure disappears, the pixel substrate 101 and the counter substrate 105, which were curved, become flat (flat), and the thickness of the cell gap 108 becomes uniform. It is preferable that the pressure difference between the internal pressure and the external pressure of the cell gap 108 is completely eliminated, but it may be reduced to the extent that the curved pixel substrate 101 and counter substrate 105 become flat.

[0023] The above process can be realized by appropriately selecting a combination of the material (viscosity and hardness), width, thickness, and width of the gap 107 of the sealing material 102, the pressure when applying pressure to the opposing substrate 105 from the outside, and the width and thickness of the cell gap 108, based on experiments, calculations, simulations, etc.

[0024] According to the above-described embodiment, deformation (distortion, etc.) of the pixel substrate 101 and the counter substrate 105 can be effectively suppressed in the manufacturing process of the image display cell.

[0025] The present invention is not limited to the above embodiment, and may have various other embodiments. For example, the gap 107 of the sealant 102 may be provided in several places, not limited to one place. Furthermore, before bonding the pixel substrate 101 and the counter substrate 105, the sealant 102 may be disposed not only on the pixel substrate 101 but only on the counter substrate 105, or on both the pixel substrate 101 and the counter substrate 105. Furthermore, when bonding the pixel substrate 101 and the counter substrate 105, instead of applying pressure to the counter substrate 105 from the outside toward the pixel substrate 101, the pixel substrate 101 may be applied pressure to the counter substrate 105 from the outside, or the pixel substrate 101 and the counter substrate 105 may be applied pressure from the outside in the direction in which they face each other. Furthermore, the surrounding pressure environment when the process of steps S2 to S5 is performed is not limited to the atmospheric pressure environment, and may be other pressure environments (pressure environments higher or lower than atmospheric pressure) in which the completed image display cell is actually used. Furthermore, the gas introduced into the cell gap 108 is not limited to air, and may be other gases such as nitrogen. Furthermore, the spacers mixed in the sealant 102 are not essential and may be omitted. Furthermore, the image display cell is not limited to an organic EL element or a DLP element, and may be another type of image display cell. [Explanation of symbols]

[0026] 101 Pixel substrate 102 Sealing material 103 Pixel Pattern 104 Electrode terminal 105 Opposing substrate 106 Air 107 Gap (Opening) 108 Cell Gap

Claims

1. A method for manufacturing an image display cell having a pixel substrate and a counter substrate, comprising the steps of: a first step of bonding the pixel substrate and the counter substrate together via a frame-shaped seal material having a gap therebetween; a second step of compressing the sealant between the pixel substrate and the counter substrate by applying pressure from the outside toward the other of the pixel substrate and the counter substrate, thereby closing the gap with the compressed sealant; a third step of reducing an internal pressure in a space surrounded by the pixel substrate, the counter substrate, and the sealant by releasing the pressure, thereby deforming at least one of the pixel substrate and the counter substrate so as to approach the other; a fourth step of increasing the internal pressure of the space by hardening the sealant, thereby making the pixel substrate and the counter substrate flat; 2. A method for manufacturing an image display cell comprising the steps of:

2. 2. The method for manufacturing an image display cell according to claim 1, wherein in the fourth step, the internal pressure of the space is increased to eliminate a pressure difference between the internal pressure and the external pressure of the space.

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