JPH03168618A - Curved liquid crystal panel - Google Patents

Abstract

PURPOSE:To form a curved panel with the liq. crystal layer thickness uniformized even if the curvature is large by providing a linear spacer on a substrate and allowing the edge line direction to coincide with the direction of the maximum curvature of the substrate. CONSTITUTION:A photosensitive polyimide resin is applied on the space part of a striped transparent electrode 2, the space part of the electrode 2 is selectively irradiated with UV, and the unirradiated part is removed to form a linear spacer 4. A seal material 3 is printed thereon, film substrates 1 are superposed and a liq. crystal 5 is injected to form a flat panel. The flat panel is stuck to a curved enclosure with an adhesive, and the curved panel is formed. In this case, the edge line of the spacer 4 is practically paralleled to the direction of the maximum curvature, hence the linear continuous spacer 4 is obtained, and the curved panel with unevenness of the liq. crystal layer thickness is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal panel used for a display device for displaying characters, images, etc., and more particularly to a curved liquid crystal panel made of a film substrate formed into a curved shape.

Conventional technology Generally, glass is used as the substrate for liquid crystal springs.
Film substrates using polymeric films are being studied in order to make them thinner and lighter.

Film substrates are more flexible than glass and do not break, so film substrate liquid panels μ can be easily curved, and can even have fairly large curvatures.

Therefore, film substrate liquid crystal panels are suitable for installation on the surface of devices with curved casings, or when a curved surface is desired from a design point of view, such as in variable-light glasses or ski goggles.

FIG. 6 shows a cross-sectional view of the film substrate liquid crystal panel.

Two film substrates 1 on which electrode patterns 2 are formed are bonded together using a sealing material 3, and a liquid crystal 6 is sealed in the gap between the substrates. The electrode pattern 2 is formed in a stripe shape in the dot matrix panel, and the surface thereof is subjected to alignment treatment (not shown) for aligning liquid crystal molecules. Spacer materials 6 are dispersed in the liquid crystal enclosure to keep the thickness of the liquid crystal layer constant. Generally, the sealing material 3 is made of a thermosetting adhesive such as an epoxy resin or an ultraviolet curable resin, and is formed into a shape surrounding the liquid crystal filled area using a screen printing method. As the spacer material 6, resin or inorganic microspheres having a constant particle size approximately equal to the required thickness of the liquid crystal layer, or glass fiber chips whose short axis is approximately equal to the thickness of the liquid crystal layer are used.

Problems to be Solved by the Invention FIG. 6 is a perspective view of a curved liquid crystal panel bent along a cylindrical surface, and the X, Y, and Z axes are set as shown in the figure. Here, the XX/direction is a straight line with 0 curvature, and the YY' direction is the direction of maximum curvature.

For buttons on conventional LCD panels, the spacer density is 60 to 6.
00 pieces/one, and the average distance between spacers is at least 40
This is more than μm, which is considerably larger than the liquid crystal layer thickness of 6 to 10 μm, and there is a problem in that when the liquid crystal panel is bent with a large curvature, the liquid crystal layer thickness becomes uneven. FIG. 7 is a schematic diagram for explaining this phenomenon, and is a cross-sectional view in the YY/direction of an extremely bent liquid crystal panel. The liquid crystal layer thickness is approximately regulated by the spacer diameter in the vicinity where the spacer e is present, but becomes smaller than the spacer diameter in the area between the spacers 60. This phenomenon is particularly noticeable in the Finolem substrate liquid crystal panel p, which has lower rigidity than glass, and there is a problem in that coloring occurs due to unevenness in the thickness of the liquid crystal layer, resulting in a significant deterioration in display quality. If an attempt is made to increase the spacer density to prevent this, the area ratio of the spacer and the poorly aligned portion near the spacer to the display pixel area will increase, resulting in a decrease in contrast. Therefore, it is necessary to increase the spacer density to prevent unevenness in the liquid crystal layer thickness. is difficult in practice.

An object of the present invention is to realize a curved liquid crystal panel Jv in which the thickness of the liquid crystal layer is uniform even if the panel has a large curvature.

Means for Solving the Problems In order to achieve the above object, the curved liquid crystal panel of the present invention is provided with a linear spacer between a pair of substrates sandwiching a liquid crystal, and the ridge direction of the spacer and the maximum curvature of the substrates The directions are configured so that they roughly match.

action The effect of the above means is as follows.

The spacer in the present invention has a linear shape substantially parallel to the maximum curvature direction and is a continuous body, so that unevenness in the liquid crystal layer thickness due to the spacer interval does not occur. In addition, if a linear spacer is formed in the striped electrode 51/<Yuichi no space portion, since no spacer is present in the display pixel portion, there is no reduction in contrast due to the spacer or alignment disturbance in the vicinity of the spacer.

EXAMPLE An example of the curved liquid crystal panel of the present invention will be described below with reference to the drawings.

FIG. 3 is a perspective view of a curved liquid crystal panel bent along a cylindrical surface, and the X, Y, and Z axes are set as shown in the figure. Here, the xx' direction is a straight line without curvature, and the YY/direction is the direction of maximum curvature.

1 is a film substrate made of PKS (polyethersulfone) resin, and 2 is a striped transparent electrode on its surface.

FIG. 2 is a cross-sectional view taken along a plane including the X-axis and 2@, and 4 is a linear spacer formed in the space of the transparent electrode. Since there is no curvature in the XX/direction, the panel cross section is straight.

FIG. 1 is a sectional view taken along a plane including the Y axis and two axes, and since the YY' direction is the direction of maximum curvature, the panel cross section is arcuate.

A perspective view of the lower substrate shown in FIG. 3 is shown in FIG. 4.

The linear spacer 4 was formed in the space of the striped transparent electrode 2 by photolithography using photosensitive polyimide resin. This can be obtained by coating a photosensitive polyimide resin to a thickness approximately equal to the thickness of the liquid crystal layer, selectively irradiating the space portions of the transparent electrode 2 with ultraviolet rays, and then developing and removing the unirradiated portions. Alternatively, it can be easily obtained by a printing method. Next, a polyimide resin for an alignment film was applied to both the upper and lower substrates, cured, and then subjected to a rubbing treatment. Furthermore, on the surface of the upper substrate, a sealing material 3 made of thermosetting epoxy resin is screen printed in a shape that surrounds the liquid crystal enclosing part and has a liquid crystal injection port in a part, and after aligning the positions of both film substrates 1, they are stacked. The sealing material 3 was cured, liquid crystal 5 was injected through the injection port, and the injection port was sealed with an epoxy resin adhesive.

Since the liquid crystal panel obtained in this way is flat, depending on the device in which the panel will be used, it may be pasted onto a curved casing using an adhesive, or the liquid crystal spring /l/ may be attached to a mechanical frame. It is fixed in a curved shape by pressing it down or the like. As another method, it is also possible to obtain a curved panel Iv in its natural state by forming the sheet material 3 into a spring/t/'i curved surface and curing it.

In this example, the liquid crystal panel (V) was bent into a cylindrical shape so that the direction of maximum curvature coincided with the spacer ridgeline, but it is not necessary to make the two coincide completely, and even if the two are misaligned by a few degrees, the effect of preventing unevenness in the liquid crystal layer thickness will not be obtained. It will be done. The effect is remarkable when the panel substrate is a polymer film, but it is not limited to this, and a thin glass substrate is equally effective. 1. Since this embodiment is a dot matrix panel, the transparent electrodes 2 are striped, but linear spacers 4 may be formed on the transparent electrodes 2 depending on the transparent electrode pattern and the curved surface of the panel. However, by making the width of the linear spacer 40 sufficiently thin, it becomes visually unnoticeable and there is no problem in practical use.

Effects of the Invention As described above, the curved liquid panel of the present invention can prevent uneven thickness of the liquid layer and the resulting deterioration of display quality without reducing contrast even when the curved surface has a large curvature (small bending radius). This expands the range of applications for liquid crystal panels, such as making it possible to use them in areas where conventional liquid crystal panels are difficult to apply, such as the corners of small-diameter cylindrical cases and the corners of prismatic cases.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a curved liquid crystal panel according to an embodiment of the present invention, FIG. 3 is a perspective view of a liquid crystal spring μ according to the same embodiment, and FIG. 4 is a cross-sectional view of a liquid crystal panel μ according to the same embodiment. Figure 6 is a perspective view of the board, Figure 6 is a cross-sectional view of a conventional liquid crystal spring, V, Figure 6 is a perspective view of a button on a conventional liquid crystal panel, and Figure 7 is a cross-sectional view of an extremely bent conventional liquid crystal panel. be. DESCRIPTION OF SYMBOLS 1... Film substrate, 2... Transparent electrode, 3... Seal material, 4... Linear spacer, 6... Liquid crystal.

Claims (1)

[Claims] A curved liquid crystal panel comprising a linear spacer between a pair of substrates sandwiching a liquid crystal, the ridgeline direction of the spacer approximately matching the maximum curvature direction of the substrates.