JPH02304527A - Liquid crystal display device for overhead projector and production of curved surface panel - Google Patents

Abstract

PURPOSE:To prevent the uneveness of contrast between upper and lower parts of the picture on a screen by sticking substrates different in the coefficient of thermal expansion to each other by thermal press-fitting to form a curved surface panel. CONSTITUTION:A soda glass plate which has 90X10<-7>/ deg.C thermal expansion coefficient and 0.7mm thickness is used as an upper electrode substrate 2, and a borosilicate glass plate which has 46X10<-7>/ deg.C thermal expansion coefficient and 0.3mm thickness is used as a lower electrode substrate 2. These two glass substrates 2 an 3 are adhered to each other with thermo-setting adhesive 5 and adhered to each other by thermal press-fitting to obtain a curved surface panel where the layer thickness of liquid crystal is uniform. In this case, the picture is always perpendicularly seen from a certain point above a liquid crystal panel 1. Thus, the uneveness of contrast in the upper part of the picture on the screen is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an overhead projector (hereinafter referred to as OHP).
related to liquid crystal display devices. Another aspect of the present invention relates to a method for manufacturing a curved panel. However, the curved panel manufactured according to the present invention can be used not only as an OHP liquid non-display device, but also as an optical element for a mirror or the like.

[Prior Art J] Conventionally, the screen has been a liquid non-display device for OHP, which is formed by sandwiching a liquid crystal layer between a pair of electrode substrates disposed facing each other. Further, two electrode substrates having the same coefficient of thermal expansion were bonded together to form a pair of electrode substrates.

[Problems to be Solved by the Invention] Figure 2 shows the change in transmittance with respect to the applied voltage when the viewing angle direction is changed in a conventional liquid crystal display device. As is clear from the figure, which shows the viewing angle, the transmittance varies depending on the viewing angle. Therefore, when used in an OHP liquid non-display device, contrast unevenness occurs between the top and bottom of the screen. In other words, O
The structure of the HP is shown in Figure 3, and when the width of the display screen is 240 mm, the viewing angle is about ±15 degrees,
The bottom of the screen becomes dark. In Figure 3, 130
131 is a light source, 131 is a mirror, and 132 is a screen.

As described above, there is a problem in that the contrast of the conventional OHP liquid non-display device differs depending on the top and bottom of the screen.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a liquid crystal display device in which contrast difference does not occur between the top and bottom of the screen.

A second object of the present invention is to provide a method for manufacturing a liquid crystal display device for achieving the above object.

[Means for Solving the Problems 1] In order to achieve the above object, the OHP liquid crystal device of the present invention is constructed as follows.

That is, there is a non-liquid display device for OHP in which a liquid crystal layer is sandwiched between a pair of electrode substrates arranged facing each other, and the electrode substrates are characterized in that the pair of electrode substrates have curved surfaces.

Further, the method for manufacturing the curved panel of the present invention is as follows. . That is, a method for manufacturing a curved panel in which a pair of substrates are arranged facing each other is characterized in that two substrates having different coefficients of thermal expansion are bonded together by thermocompression using a thermosetting adhesive.

[Work] FIG. 1 shows the construction of an OHP liquid non-display device according to the present invention.

1 is a liquid crystal panel and has a single curved surface. The liquid crystal panel 1 has a liquid crystal 4 sandwiched between an upper electrode substrate 2 and a lower electrode substrate 3, and is sealed with a sealant (thermosetting adhesive) 5. A polarizing plate, an optically anisotropic body, etc. may be provided in the liquid crystal cell l. This allows you to always view the screen vertically from a certain point above the LCD panel. Therefore, when used as an OHP liquid crystal display device, uneven contrast between the top and bottom of the screen can be prevented.

[Example J Example 1 In Fig. 1, 0.7 m of soda glass was used on the upper electrode substrate 2.
m thickness, lower electrode substrate 3 is made of borosilicate glass (Corning 7
059 (manufactured by Corning Inc.) with a thickness of 03 mm. The coefficient of thermal expansion of soda glass is 90 X 10-'/"C, and the coefficient of thermal expansion of Corning 7059 is 46 X I O-'/"
'C. Paste the above two glass substrates together at 160°
It was bonded by thermocompression using C.

As a result, a curved panel with a uniform liquid crystal layer thickness was obtained. Therefore, the radius of curvature was measured to be 1621 mm at room temperature.
It became.

Next, when used as an OHP display device, a screen with no vertical unevenness was obtained.

Example 2 In the same manner as in Example 1, soda glass 0 was applied to the upper electrode substrate 2.
．． 7mm thick, lower electrode substrate 3 is Corning 7059 0.
Using a thickness of 7 mm, the adhesive was bonded by thermocompression at 180°C. The radius of curvature was then 1786 mm at room temperature. When used as an OHP display device, vertical unevenness was improved compared to Example 1.

Example 3 The same substrate as in Example 3 was used and bonded by thermocompression at 200°C. The radius of curvature was then 1988 mm at room temperature.

[Effects of the Invention] As explained above, according to the present invention, when substrates having different coefficients of thermal expansion are bonded together by thermocompression bonding, a curved panel is created.
If this curved panel is used in an OHP liquid non-display device, an even display can be obtained at the top and bottom of the screen.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a liquid non-display device for OHP according to the present invention. FIG. 2 is a diagram showing changes in transmittance with respect to applied voltage when the angular direction of a conventional OHP liquid non-display device is changed. FIG. 3 is a schematic diagram showing the Of-IPI71 structure. That’s all for number one! 20th

Claims (2)

[Claims] (1) A liquid crystal display device for an overhead projector comprising a liquid crystal layer sandwiched between a pair of electrode substrates disposed facing each other, wherein the pair of electrode substrates have a curved surface. Display device. (2) A method for manufacturing a curved panel in which a pair of substrates are arranged facing each other, which is characterized in that two substrates having different coefficients of thermal expansion are bonded together by thermocompression using a thermosetting adhesive. Production method.