JP3197982B2 - Method of manufacturing spacer for liquid crystal display element - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a spacer for a liquid crystal display device using a plastic substrate. 2. Description of the Related Art A conventional general liquid crystal display device is shown in FIG.
A plurality of strip-shaped transparent electrodes 4 for transmitting electric signals are respectively arranged on a pair of transparent substrates 1 made of, for example, a plastic material, and a polyimide or the like is applied on each substrate, and a rubbing process is performed. After the alignment film is formed, the substrates 1 are bonded together with the spacers 10 facing each other so that the strip-shaped transparent electrodes 4 are perpendicular to each other, and the liquid crystal 2 is injected between the substrates. The distance between two substrates of the liquid crystal display device is controlled by spacer grains 10 between the two substrates. The spacer particles 10 have a diameter of 2 μm to 10 μm.
Glass fibers having a uniform diameter of about μm, or resin or ceramic small balls are used. The arrangement of the spacer particles is such that, for example, as shown in FIG. 5, the substrate 1 is placed in a box 9 from which dust and the like are completely removed, and the spacer particles 10 are scattered from the inlet 11. Before laminating the substrate 1, a method of spraying an air current or a solvent in which the spacer particles 10 are dispersed on one substrate 1 is generally used. Further, instead of the step of applying the spacer particles 10 as described above, a technique of transferring and forming a large number of projections on a plastic substrate by injection molding is disclosed in Japanese Patent Laid-Open Publication No.
305621 "and the like. This is a technique in which a spacer is directly formed on a plastic substrate to thereby maintain a uniform spacing between the substrates. [0005] In the prior art,
When the spacer grains 10 are applied, it is difficult to uniformly scatter the spacer particles 10 on the substrate 1. If there is unevenness in the dispersion, the distance between the substrates cannot be kept uniform, and display unevenness appears, as shown in the X portion of FIG. There is a possibility that a point defect due to condensation of the spacer particles 10 or a possibility that the spacer particles 10 as shown in a Y portion are put on the active element 5 and the element 5 is broken. Further, since the spacer grains 10 are interposed in the liquid crystal 2 between the substrates 1, the orientation of the liquid crystal molecules is disturbed by the presence of the spacer grains 10, and the liquid crystal molecules oriented in different directions regardless of the voltage. This causes the display to be disturbed due to the disturbance of the orientation of the liquid crystal molecules. In particular, in the case of performing enlarged display as a projector, since each pixel is enlarged, problems such as partial disturbance of vision and weak contrast are caused. was there. In particular, in order to sharpen the enlarged display, it is necessary to reduce the size of each pixel. For this reason, the size of the spacer particles 10 cannot be ignored, and the display electrode 4 The upper spacer grains 10 are removed, and spacer grains 10 are added to unnecessary portions of the spacer grains 10.
It has become necessary to fix the spacer particles 10 to a predetermined portion so that no intrusion occurs. Further, the method of transferring and forming a spacer by injection molding as disclosed in Japanese Patent Application Laid-Open No. 4-305621 solves the above-mentioned problems such as uneven distribution and destruction of active elements. However, it is necessary to finely mold the mold on the order of several μm, which is the size of the spacer, and to accurately carve the shape of the spacer, advanced technology is required, and the manufacturing cost is also rising. I will. In addition, when performing the injection molding, even if there is only a small amount of dust, the dust adheres to the substrate surface or is contained in the substrate, and if the dust is charged, it is formed on the substrate. There is a problem that the property of the active element is changed by invading into the film, thereby causing a defect as a liquid crystal display device. SUMMARY OF THE INVENTION In view of the above problems, the present invention makes it possible to easily and inexpensively maintain uniform spacing between substrates without causing display unevenness, point defects, destruction of active elements, etc. due to scattering of spacers on unnecessary portions. An object of the present invention is to provide a method for manufacturing a spacer for a liquid crystal display element. According to the present invention, there is provided a method of manufacturing a spacer for a liquid crystal display element for interposing a liquid crystal between a pair of plastic substrates having a predetermined distance. The surface of the plastic substrate on the side in contact with the liquid crystal is locally heated and melted by a heating plate having predetermined projections, and the surface of the plastic substrate is raised by raising the heating plate to a predetermined height, A method for manufacturing a spacer for a liquid crystal display element, wherein the protrusion formed by cooling in the raised state is used as a spacer for keeping a uniform substrate spacing. According to the above-mentioned means for solving the above problems, the spacers can be manufactured at appropriate arbitrary intervals by setting the needle-like portions of the heating plate in advance in accordance with the density of the spacers and predetermined positions. Accordingly, it is possible to prevent display unevenness, point defects, active element destruction, and the like of the liquid crystal panel due to uneven distribution of the spacers. Further, the heating plate needle-like portion is melted by applying heat from a heating plate made of a heating wire or the like to a predetermined portion of the plastic substrate, and the heating plate needle-like portion is slowly pulled up to a required height. Protrusions are formed by raising the surface of a plastic substrate and cooling it as it is, and since the protrusions are used as spacers, it is possible to reliably manufacture spacers for liquid crystal display elements without specially requiring advanced technology. Becomes possible. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a spacer for a liquid crystal display device according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a liquid crystal display device in which a spacer is manufactured according to an embodiment of the present invention, and FIGS. 2 (a) and 2 (b).
Is a perspective view showing a heating plate used for manufacturing the spacer, FIG. 3 is a cross-sectional view showing a spacer manufacturing apparatus including the heating plate used for manufacturing the spacer, and FIG. It is sectional drawing which shows the state of a board and a plastic substrate. As shown in FIG. 2, the heating plate used for manufacturing the spacer of this embodiment is a heating plate flat portion 7 having a size substantially the same as that of the liquid crystal panel and a thickness of several mm to several cm. A heating wire 6 made of a nichrome wire or the like for controlling the temperature is arranged on the surface of the heating plate. Metals that do not melt when heated to temperature, such as gold, silver,
There is provided a sword-shaped heating plate needle-like portion 8 in which needles made of iron, nickel, tungsten, or alloys of these having a diameter of 2 μm to 10 μm and a length of about 0.1 mm to 3 mm are set at predetermined positions. Further, as shown in FIG. 3, the heating plate comprises:
Aligner stage 1 for secure alignment of substrate 1
2 and the like, and is supported by a heating plate support 13 in the spacer manufacturing apparatus,
The distance between the heating plate and the plastic substrate 1 is controlled so as to be slidable up and down, and the temperature of the needle-shaped portion 8 of the heating plate is also controlled. Further, the plastic substrate 1 of the liquid crystal panel having the above configuration and used in the spacer manufacturing process of the present embodiment.
Is a polyether sulfone having a melting point of about several hundred degrees,
It is made of resin such as polyethylene terephthalate,
As shown in FIG. 3, the plastic substrate 1 is securely set on an aligner stage 12 by a vacuum chuck or the like, and is moved to a desired position under the heating plate by the aligner stage 12 so that the plastic substrate 1 The positioning of the plastic substrate 1 is reliably performed. Further, the needle arrangement of the heating plate needle-like portion 1 at that time is set in advance at a predetermined position such that display unevenness, point defects, active element destruction and the like on the plastic substrate 1 do not occur. I have. Referring to FIGS. 4 (a) and 4 (b), a description will be given of a spacer manufacturing process by the spacer manufacturing apparatus in which the heating plate and the plastic substrate 1 are arranged as described above. First, the plastic substrate 1 is set at a predetermined position of the spacer manufacturing apparatus as shown in FIG.
The heating plate supporting portion 13 is moved closer to the plastic substrate 1, and the heating plate needle-shaped portion 8, which is controlled to a temperature of about the melting point of the plastic, is brought into horizontal contact with the plastic substrate 1 as shown in FIG. Let it. While the heating plate needle-shaped portion 8 and the plastic substrate 1 are in contact with each other, the heating plate needle-shaped portion 8 is heated for several seconds to melt the plastic surface of the plastic substrate 1. Thereafter, as shown in FIG. 4 (b), the tip of the needle-like portion 8 of the heating plate in contact with the surface of the plastic substrate 1 is set at a predetermined height corresponding to a predetermined substrate interval. Then, the heating is completed by raising the surface portion of the plastic substrate 1 with which the tip of the heating plate needle-shaped portion 8 is in contact, and cooling to a temperature at which the raised plastic portion solidifies. According to the method described above, the protruding portions 3 are formed on the plastic substrate 1 on which the electrodes 4 and the active elements 5 and the like are formed, and an alignment film for aligning the liquid crystal is formed on the substrate 1. Further, after similarly forming an alignment film on a counter substrate provided with a counter electrode, the element substrate 1
The liquid crystal panel shown in FIG. 1 is completed by bonding the liquid crystal 2 and closing the liquid crystal 2 by closing the liquid crystal 2 and closing the liquid crystal 2. However, the order of forming the projections 3 after forming the electrodes 4 and the active elements 5 and the like may be reversed, and the respective electrodes may be formed by peripheral deformation caused by the formation of the projections 3. Therefore, it is desirable to form the protruding portions 3 on portions other than the electrodes 4 and the active elements 5. Further, in this embodiment, the protruding portion 3 is formed on the element substrate 1. However, it is also possible to form the protruding portion 3 on the opposing substrate. In this case, when bonding both substrates,
It must be formed at a position that does not face each of the electrodes 4, the active element 5, and the like. Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and a method of using a spacer manufacturing apparatus having another configuration is of course possible. According to the present invention, it is not necessary to use a spacer 10 made of a plastic sphere or the like which is difficult to apply uniformly, and it is also possible to display the electrodes 4 and the active elements 5 on the plastic substrate 1. Can be set in advance so that the spacers 3 do not come into contact with the parts related to the above, so that various problems such as display unevenness, point defects, and active element destruction can be completely eliminated. Further, since the heating plate in the above-mentioned spacer manufacturing apparatus has a very simple structure, the spacer 3 for maintaining the distance between the substrates easily and inexpensively can be manufactured without requiring any advanced technology. It is possible to do.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a liquid crystal display device in which a spacer is manufactured according to one embodiment of the present invention. FIG. 2 is an enlarged view showing a heating plate according to one embodiment of the present invention. FIG. 3 is a sectional view showing a spacer manufacturing apparatus according to one embodiment of the present invention. FIG. 4 is a sectional view of a heating plate and a plastic substrate showing a spacer manufacturing process according to one embodiment of the present invention. FIG. 5 is a sectional view showing a conventional spacer coating step. FIG. 6 is a sectional view of a liquid crystal display device manufactured by a conventional spacer coating process. [Description of Signs] 1 Plastic substrate 2 Liquid crystal 3 Protrusion spacer 4 Electrode 5 Active element 6 Heating wire 7 Heating plate flat portion 8 Heating plate needle portion 9 Box 10 Spacer grain 11 Spacer inlet 12 Aligner stage 13 Heating plate support

Claims (1)

(57) A method of manufacturing a spacer of a liquid crystal display element for interposing a liquid crystal between a pair of plastic substrates having a predetermined distance, wherein at least one of the plastic substrates has a surface in contact with the liquid crystal. Is formed by locally applying heat and melting by a heating plate having predetermined projections, raising the heating plate to a predetermined height, raising the surface of the plastic substrate, and cooling the plastic substrate in the raised state. The method of manufacturing a spacer for a liquid crystal display device, wherein the protrusion is a spacer that keeps a uniform substrate interval.