JP2006208867A - Manufacturing method of liquid crystal panel for projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sticking method of a liquid crystal cell for a liquid crystal projector and a dust preventing glass with high production efficiency. <P>SOLUTION: In a manufacturing method of the liquid crystal panel for the liquid crystal projector wherein first and second dust preventing glasses are stuck to first and second substrates, respectively, in a liquid crystal element compose of the first and the second substrates, at least one or both of sticking of the first substrate and the first dust preventing glass and sticking of the second substrate and the second dust preventing glass are performed by using a curable sheet-shaped adhesive which is a solid at normal temperature and melted and liquified by heating and three-dimensionally cross-linked by irradiation with light and a sticking step includes a step for disposing a plurality of dust preventing glasses in a face direction in a row shape or a grating-shape, a step for disposing the curable sheet-shaped adhesive having a dimension capable of covering all the plurality of dust preventing glasses and a step for disposing the substrates on the curable sheet-shaped adhesive so as to be positioned in the same positions as the dust preventing glasses and thermally pressing and sticking. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a liquid crystal panel for a projector, and more particularly to a method for manufacturing a liquid crystal panel for a projector, which is characterized by a method of bonding a liquid crystal cell and dust-proof glass.

  In recent years, projection display devices using liquid crystal display elements, that is, liquid crystal projectors, are rapidly spreading, and accordingly, demand for liquid crystal panels for projectors is also rapidly increasing. Therefore, it is required to increase the production efficiency during the manufacturing process of the liquid crystal panel.

A liquid crystal projector can display a large image by projecting an image formed by a liquid crystal cell onto a screen with light from a light source. At this time, if foreign substances such as dust adhere to the surface of the liquid crystal cell, they are enlarged and projected onto the screen, so that the influence of the dust becomes very large. As a method for solving this problem, if a liquid crystal panel is used with a dust-proof glass attached to the surface of the liquid crystal cell, even if a foreign object adheres to the liquid crystal panel, the image due to the foreign object becomes defocused, The impact can be reduced. This technique is described in Patent Document 1 and the like.
JP, 2000-347168, A As a laminating method of a liquid crystal cell and dustproof glass, the pasting method by an adhesive is common, but since the adhesive is liquid, the interval between a liquid crystal cell and dustproof glass depends on the amount applied. In order to maintain a constant interval, the coating amount must be strictly controlled and managed so as not to cause coating unevenness. In addition, if the adhesive is liquid, there is a problem that it protrudes from the edge of the bonding surface, the dustproof glass shifts from bonding to curing, and further, the adhesive is applied to each relatively small liquid crystal cell, It was necessary to take a process of bonding and hardening the dust-proof glass, and the work was complicated.

  The present invention has been intensively studied in order to solve the above-mentioned problem of bonding with a liquid adhesive, and a plurality of liquid crystal cells for liquid crystal projectors and dust-proof glass can be bonded together, and further, batch bonding can be performed. The bonded liquid crystal cells are connected by a sheet-like adhesive and can be handled in the same way as a single glass plate, providing improved bonding and improving the production efficiency of projector liquid crystal cells. The purpose is to do.

  That is, the present invention provides a liquid crystal element in which a first substrate and a second substrate having a larger area than the first substrate are bonded to each other with an interval, and a liquid crystal is sealed in the interval. In the method of manufacturing a liquid crystal panel in which a first dustproof glass having substantially the same shape as that of the second substrate and a second dustproof glass having substantially the same shape as the second substrate are bonded to the second substrate, the first substrate and the first dustproof glass A curable sheet in which at least one or both of the bonding or the second substrate and the second dust-proof glass is solid at room temperature, melts and liquefies by heating, and is three-dimensionally crosslinked by irradiation with light. , And a process of arranging a plurality of dustproof glasses in a line or grid pattern in the surface direction as a laminating process, a curable property with a dimension that can cover all of the plurality of dustproof glasses Dust-proof glass sheet adhesive Placing on a manufacturing method of a projector for a liquid crystal panel characterized in that the substrate is a step, disposing thermocompression bonding dustproof glass the same position like in the curable sheet.

  The second substrate of the present invention is formed by forming a thin layer transistor element active element, a pixel electrode made of a transparent conductor such as ITO, a wiring, an alignment film, etc. on a plate such as glass, and is called a so-called element substrate. . In addition, the first substrate of the present invention is formed with a counter electrode and an alignment film and forms an active matrix together with the second substrate, and is called a so-called counter substrate. The first substrate and the second substrate are joined at a predetermined interval, and liquid crystal is sealed in the gap to form a liquid crystal element. The area of the second substrate is larger than that of the first substrate. Specifically, when the first substrate and the second substrate are joined, only one end of the second substrate protrudes, and the flexible wiring substrate is projected to the electrode of the protruding portion. Is connected. These liquid crystal elements are known, and currently known liquid crystal elements can be used in the present invention.

  As described above, the dust-proof glass reduces the influence on the projected image even if dust adheres to the liquid crystal element, and is attached to both the first substrate and the second substrate of the liquid crystal element. The first dust-proof glass attached to the first substrate has substantially the same shape and dimensions as the first substrate, and is attached to the surface of the first substrate opposite to the surface facing the liquid crystal. Similarly, the second dust-proof glass attached to the second substrate has substantially the same shape and dimensions as the second substrate, and is attached to the surface of the second substrate opposite to the surface facing the liquid crystal. The mounting can be performed by thermocompression bonding using a curable sheet adhesive.

  In the present invention, a method in which a first substrate and a second substrate are bonded in advance to form a liquid crystal element, and dust-proof glass is bonded to each substrate is preferable. At this time, the first substrate and the first dust-proof glass are pasted together, and the second substrate and the second dust-proof glass are pasted together, and the substrates are pasted together in a state where the substrate and the dust-proof glass are integrated, respectively. Although a method of encapsulating the substrate is also conceivable, it is not preferable because the electrode and the alignment film on the substrate directly receive the heat and pressure of thermocompression bonding. In addition, the first dustproof glass and the second dustproof glass may be attached in either order.

  The curable sheet adhesive of the present invention is solid at room temperature and melts and liquefies by heating. Even after heating, when the temperature is lowered to room temperature by cooling or natural standing, it becomes solid again. Therefore, the curable sheet adhesive is melted by sandwiching the curable sheet adhesive between the member to be bonded and heating. After that, when the heat is removed, it becomes solid again and the member to be bonded can be fixed. At this time, when the fixed member to be bonded is heated again, the member to be bonded can be peeled off. The curable sheet adhesive of the present invention is cured by three-dimensional crosslinking of the components of the curable sheet adhesive when irradiated with light. After three-dimensional crosslinking by light irradiation, it does not melt even when heated. Therefore, it cannot be peeled off by heating, but has good heat resistance and excellent adhesion.

  Specifically, the curable sheet-like adhesive is solid at room temperature, and is preferably a compound that melts and liquefies by heating to 50 to 100 ° C. and then solidifies again by cooling to room temperature. The cured adhesive is preferably colorless and transparent. Specifically, it is desirable that the visible light transmittance at a wavelength of 400 nm or more is 90% or more. Moreover, the compounding composition which can be hardened | cured by ultraviolet rays or visible light ray hardening is preferable for the light to irradiate.

  Examples of such a composition include a composition containing a thermoplastic elastomer and a photoinitiator in a compound having a (meth) acryloyl group as a curing component, for example, urethane (meth) acrylate and epoxy (meth) acrylate.

  According to the present invention, the substrate of the liquid crystal cell and the dust-proof glass can be mounted at a uniform interval by an easy method, and in particular, a plurality of liquid crystal panels can be bonded together, and further, bonded together. Since the processed liquid crystal panels are connected by a sheet-like adhesive to form a single plate, it is not necessary to use a jig for holding a plurality of pieces, and the process can be shifted to the next step. Therefore, production efficiency can be improved. In addition, when light irradiation is not performed, peeling can be performed by heating. Therefore, when there is a problem in the operation check, peeling can be repaired, so that the yield is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 is a cross-sectional view showing a state before use of the curable sheet adhesive. The curable sheet adhesive 7 has release films 5 and 6 formed on both sides. In this embodiment, a sheet-like adhesive 7 (hereinafter, the curable sheet-like adhesive is sometimes simply referred to as a sheet-like adhesive) having a release film formed thereon is used. Alternatively, a release film may be formed on one side and wound into a reel. 10-100 micrometers is suitable for the thickness of a curable sheet adhesive.

  FIG. 3 is a schematic cross-sectional view of the projector liquid crystal cell 8. An actual liquid crystal cell has a complicated structure including a liquid crystal layer, a sealant, and the like, but in the embodiment of the present invention, a second substrate 9 as an element substrate, a first substrate 10 as an opposite substrate, and an electrode 11 are shown. Other structures are omitted. The second substrate has a larger area than the first substrate, and protrudes from the first substrate at one end. An electrode 11 is formed on the protrusion, and a flexible substrate (not shown) is connected to the electrode 11.

  Hereinafter, bonding of the second dustproof glass and the second substrate will be described. FIG. 1 is a perspective view showing a state in which the second dustproof glass 1 is arranged in a grid pattern. Here, 16 pieces of the second dustproof glass are arranged in 4 × 4 rows, but it goes without saying that this number can be changed as appropriate. In addition, a plurality may be arranged in a line instead of a grid pattern. Further, the second dustproof glass may be arranged in a state where they are in close contact with each other, or may be arranged at a predetermined interval. In addition, it is preferable to use a jig as necessary in order to align in a grid pattern. In this embodiment, the partition plate 3 is formed on the support plate 4 and the dust-proof glass is disposed in close contact with the partition plate. For example, a recess into which the dust-proof glass enters the support plate is formed and the dust-proof glass is fitted into the recess. You may do it.

  Although the curable sheet adhesive 7 is arranged on the second dustproof glass 1 arranged in a grid pattern, the curable sheet adhesive 7 can cover all the arranged second dustproof glasses 1. Is necessary, and a continuous state that is not divided is used. It is preferable to use a dust-proof glass assembly having the same dimensions as the vertical and horizontal lengths, preferably arranged in rows or grids. Thereby, the sheet-like adhesive 5 does not protrude. As another method, the positioning accuracy of the sheet-like adhesive 7 can be moderated by making the sheet-like adhesive 7 larger than the length and width of the second dust-proof glass assembly. it can. In this case, since the sheet-like adhesive 7 protrudes from the second end dust-proof glass 1, it must be cut with a cutter or the like.

  FIG. 4 is a cross-sectional view of the aggregate 2 in which a plurality of second dust-proof glasses 1 are arranged as seen from the side. The curable sheet-like adhesive 7 is peeled off from the release paper 6 or peeled off from the reel-like state to expose the sheet-like adhesive 7. It is preferable that the other surface of the sheet-like adhesive 7 is in a state where the release film 5 is stuck. The curable sheet-like adhesive 7 in this state is arranged so as to cover the entire second dustproof glass 1 arranged in a row or grid pattern. Thereafter, the sheet adhesive 7 and the second dust-proof glass 2 are brought into close contact with each other by thermocompression bonding. For the thermocompression bonding, it is preferable to use a roll laminator capable of applying a pressing pressure while rotating the heated rubber roller 10. Moreover, when the curable sheet-like adhesive 7 is slightly tacky, it is not always necessary to perform thermocompression bonding. Thereafter, the release film 5 is peeled off to expose the sheet adhesive 7.

  Next, the surface of the second substrate 9 of the liquid crystal cell 8 manufactured in a separate process is placed on the exposed sheet-like adhesive 7 so as to face down. The position to arrange | position is arrange | positioned in the position corresponding to 2nd dustproof glass. This is shown in FIG. In FIG. 5, the second substrate of each liquid crystal cell 8 is disposed directly above the second dust-proof glass via the sheet adhesive 7. The second dust-proof glass and the second substrate can be bonded together by thermocompression bonding in this step. However, at this stage, the first dust-proof glass is not yet bonded to the first substrate. The step of bonding the first substrate and the first dustproof glass will be described later. In this step, the first substrate and the first dustproof glass are bonded together, and the second substrate and the second dustproof glass are bonded simultaneously. Therefore, if it is performed at the same time, there is no need to heat-press at this stage.

  Next, the bonding of the first substrate and the first dustproof glass will be described. Similar to the above-described method of laminating the second substrate and the second dust-proof glass, first, the first dust-proof glass is arranged in a row or grid pattern. (Not shown) Next, in the same manner as in the second dustproof glass step, the release film is peeled off from the curable sheet-like adhesive, the adhesive layer is exposed, and a plurality of first dustproof glass aggregates arranged. Arrange to cover the whole. Subsequently, the first dust-proof glass and the sheet-like adhesive are brought into intimate contact with each other in the same manner by a heat roller or the like. At this stage, these first dustproof glasses are formed into a single sheet by a sheet-like adhesive, and are individually divided in this step. That is, the release film adhering to the opposite surface of the sheet adhesive is peeled off, and the sheet adhesive is cut by a cutter or the like according to the shape of the dust-proof glass. At this time, an environment in which dust does not adhere to the sheet-like adhesive is necessary. Although it is possible to prevent dust from adhering to the sheet-like adhesive by peeling off the release film after cutting, the release film must be peeled off individually, and this selection is appropriately determined according to the environment at the time of manufacture. be able to. What was obtained by this process is shown in FIG. In the figure, 12 is a first dustproof glass and 13 is a sheet-like adhesive. In this figure, the release film is peeled off first.

  Next, a member in which the first dust-proof glass 12 and the sheet-like adhesive 13 shown in FIG. 6 are integrated is a first member in which the second dust-proof glass 1 and the second substrate shown in FIG. Bond to the substrate. This is shown in FIG. The first dust-proof glass is arranged so that the sheet-like adhesive integrated with the first dust-proof glass is in contact with the first substrate. The position to be arranged is arranged at a position corresponding to the first substrate. In short, the first substrate of each liquid crystal cell 8 is arranged directly below the first dust-proof glass via the sheet-like adhesive 13. Next, the first dust-proof glass and the first substrate can be bonded together by thermocompression bonding. If the heat and pressure bonding is not performed in the process of bonding the second substrate and the second dustproof glass, the first substrate and the first dustproof glass are bonded and the second substrate and the second dustproof glass are bonded by this process. Can be performed simultaneously.

  Here, the adhesion between the dust-proof glass and the sheet-like adhesive may be applied with a high pressure with a heating roller or the like, but the liquid crystal cell may be damaged when a high pressure is applied. Therefore, it is preferable to use a vacuum heating device for thermocompression bonding. Examples of the vacuum thermocompression bonding apparatus include a diaphragm type vacuum laminating apparatus and a vacuum press apparatus. By applying a vacuum, it is possible to achieve close contact without using a high pressure. A schematic of these devices is shown. FIG. 8 is a sectional view showing the concept of a diaphragm type vacuum laminating apparatus, and FIG. 9 is a conceptual view of a vacuum press apparatus. In FIG. 9, the diaphragm rubber 16 is separated from the first chamber 17 and the second chamber 18 through the diaphragm rubber 16, and the second chamber 18 including the hot plate 19 is evacuated to release the first chamber 17 to the atmosphere. Swells to the second chamber 18 side, and the object to be bonded can be pressed in a vacuum while being heated by being accommodated in the second chamber. 9 is a vacuum press apparatus that can apply a pressing pressure in vacuum by evacuating the inside of the chamber 20 and pressing the hot plates 21 and 22 disposed above and below with a hydraulic or air cylinder 23 in FIG.

  The liquid crystal panel heat-pressed by the above method is cooled to near room temperature. When cooled, the sheet adhesives 7 and 14 are solidified again, and the respective dust-proof glasses are integrated with the substrate via the curable sheet adhesive. At this time, since the sheet-like adhesive 7 between the second dust-proof glass 1 and the second substrate 9 is a continuous sheet-like shape, the liquid crystal panels are connected to each other between adjacent liquid crystal panels, such as a jig. Can be handled together without using. Therefore, the work in the next process, such as connecting a flexible substrate to the next electrode, does not require a jig for linking multiple liquid crystal panels, and can handle multiple liquid crystal panels easily integrated on a flat surface. Is easy.

  When there is no need to work with a plurality of pieces, they can be divided into individual liquid crystal panels. It can also cut | disconnect by cut | disconnecting with a cutter etc. or bending the adjacent liquid crystal panel. The divided liquid crystal panel can be represented in FIG.

  In the above-described process, the curable resin layer 7 of the divided liquid crystal cell laminate 24 is solid but uncrosslinked at this time, and the second dust-proof glass 1 and the first dust-proof glass 12 are heated by heating again. The liquid crystal cell can be peeled off from the second substrate 9 and the first substrate 10. Therefore, it is possible to repair the defect by inspecting and removing a dust-proof glass by reheating when a defect such as the mixing of foreign matter occurs.

  Finally, the inspected non-defective liquid crystal panel is completely cured by irradiation with ultraviolet rays or visible light rays. The cured sheet-like adhesive is three-dimensionally cross-linked, so that it does not melt even if it is overheated again, and the reliability during heating of the liquid crystal panel can be improved.

The present invention is used for a liquid crystal panel used in a liquid crystal projector.

The perspective view which shows the state which has arrange | positioned the 2nd dustproof glass based on this invention in the grid pattern shape. Sectional drawing which showed the structure of the curable sheet-like adhesive used by this invention Sectional drawing which showed the outline of the liquid crystal cell used by this invention Sectional drawing which shows the process of thermocompression-bonding a curable sheet adhesive to 2nd dustproof glass based on this invention. Sectional drawing which shows the state which has arrange | positioned the liquid crystal cell to the 2nd dustproof glass based on this invention Sectional drawing which shows the state which made the curable sheet adhesive contact | adhere to the 1st dust-proof glass based on this invention Sectional drawing which shows the state which bonded the 1st dustproof glass and the 2nd dustproof glass to the liquid layer cell based on this invention Sectional drawing which shows the structure of the diaphragm type vacuum laminating apparatus used by this invention Sectional drawing which shows the structure of the vacuum press apparatus used by this invention Sectional drawing which shows the structure of the liquid crystal panel obtained by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 2nd dustproof glass 5,6 Release film 7,13 Curable sheet adhesive 8 Liquid crystal cell 9 2nd board | substrate 10 1st board | substrate 12 1st dustproof glass

Claims (1)

A liquid crystal element in which a first substrate and a second substrate having a larger area than the first substrate are bonded with an interval and liquid crystal is sealed in the interval, and the first substrate has substantially the same shape as the first substrate. In the method for manufacturing a liquid crystal panel in which the first dust-proof glass and the second dust-proof glass having the same shape as the second substrate are bonded to the second substrate, the first substrate and the first dust-proof glass are bonded, or At least one or both of the bonding between the second substrate and the second dust-proof glass is solid at room temperature, melted and liquefied by heating, and curable sheet-like adhesive that is three-dimensionally crosslinked by irradiation with light. As a pasting process, a plurality of dustproof glasses are arranged in a line or grid pattern in the surface direction, and a curable sheet adhesive having a dimension capable of covering all of the plurality of dustproof glasses. To place the dust on the dust-proof glass The method of projector liquid crystal panel characterized in that the step of placing the substrate on the dustproof glass and the same position like in the curable sheet heat pressing.