JPS6229780B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal device using a surface acoustic wave element material.

An object of the present invention is to control the alignment of liquid crystals using surface acoustic waves.

Conventional liquid crystal devices have mainly been so-called electro-optical conversion elements whose optical properties are changed by external electrical signals. For example, it is used for displaying various devices such as optical shutters. Liquid crystal display devices include a dynamic scattering type that uses light scattering effects, a guest host type that adds dye to liquid crystal,
There are twisted nematic types that utilize the optical rotation of liquid crystals and their disappearance. Other uses of liquid crystal devices include forming hologram patterns and temperature sensors. In particular, among the above-mentioned display devices, guest-host type and twisted nematic type liquid crystal display devices are also used for color display. For the former, the type of color is limited to the color of the pigment added. Regarding the latter,
The liquid crystal has a 90° twisted structure, and a pair of polarizing plates are provided on the outside to determine the angle between the long axis direction of the liquid crystal molecules in contact with the upper substrate and the polarization direction of the upper polarizing plate, or the long axis of the liquid crystal molecules in contact with the lower substrate. By setting the angle between the polarization direction and the polarization direction of the lower polarizing plate at 45 degrees and utilizing birefringence, it is possible to change the color by adjusting the voltage. However, in this case, black and white display cannot be performed. The present invention can provide a device that can utilize liquid crystals in addition to the above-described usages and effects. The present invention will be explained below using the drawings. FIG. 1a is a plan view of an embodiment of the present invention;
1 and 22 are a lower substrate and an upper substrate made of surface acoustic wave device material. 23 is a sealing member, 24
and 25 are interdigital electrodes provided on the inner surfaces of the lower and upper substrates, respectively. 26 and 27 are transparent electrodes for pattern display provided on the inner surfaces of the lower substrate and the upper substrate, respectively. FIG. 1B is a cross-sectional view of FIG. 1A, and 28 is a liquid crystal with negative induced anisotropy added with a dye, which is aligned perpendicularly to the substrate as shown in the figure by processing the substrate for vertical alignment. By applying a voltage between electrodes 26 and 27, this liquid crystal changes its direction horizontally with respect to the substrate surface at a voltage above a threshold voltage. In the case of a conventional display device of this type, that is, in the case of a display device in which the substrate is an ordinary glass substrate and there is no interdigitated electrode in FIG. The dyes are arranged perpendicularly to the substrate surface, and the electric field vibration direction of the light incident on the display device is horizontal to the substrate surface, so the absorption of light by the dye is weak and the whole is almost transparent. Conversely, when a voltage is applied to the pattern display electrode, the dye molecules change their orientation in the horizontal direction together with the liquid crystal molecules. Therefore, the absorption of light by the pigment becomes stronger and becomes colored, resulting in a colored display pattern appearing on an almost transparent background. However, a major problem with this conventional method is that when a voltage is applied, the dye molecules change direction in a direction parallel to the substrate, but the direction is random. Therefore, the colored portion has a mottled pattern, which is very unsightly in appearance.
FIG. 1b according to the invention makes it possible to improve this drawback. In other words, when applying voltage to the pattern display electrodes, the interdigitated electrodes should be
When a 10 MHz signal is input and an elastic wave is propagated continuously on the substrate surface, the elastic wave becomes a standing wave 29 as shown in Fig. (without diagonal lines), the directions are unified perpendicular to the traveling direction of the elastic waves and are horizontal to the substrate surface. Therefore, the conventional mottled pattern is eliminated and the display appearance is improved. In a liquid crystal device in which a guest-host type liquid crystal with negative dielectric anisotropy is sandwiched between a pair of substrates, the pair of substrates are formed of a surface acoustic wave element material, and intersecting finger electrodes are connected to one substrate and the other substrate. placed inside the
Since the intersecting directions of the interdigitated finger electrodes are arranged in parallel in each of the interdigitated finger electrodes of the one group and the other substrate, when a voltage is applied to the pattern display electrode, the dye molecules in the applied part The directions of the liquid crystal molecules are parallel to the substrate and aligned in the same direction. Therefore, the colored display in the part to which the voltage is applied is perfect, and the appearance quality, which is important for a display device, is very good, and the contrast ratio is also greatly improved, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1a is a plan view of an embodiment of the invention. Figure 1b
is a sectional view of FIG. 1a. FIG. 1c is a perspective view of an example of operation. 21, 22...Surface wave elastic element material, 23...
Seal member, 24, 25... crossed finger electrode, 26,
27...Transparent electrode, 28...Guest host liquid crystal,
29...Elastic standing wave.

Claims (1)

[Claims] 1. In a liquid crystal device in which a dye-added liquid crystal with negative dielectric anisotropy is sandwiched between a pair of substrates, the pair of substrates are formed of a surface acoustic wave element material, and intersecting finger electrodes are connected to one substrate. are arranged inside the one substrate and the other substrate so that the elastic wave propagation direction in the substrate is the same as the elastic wave propagation direction in the other substrate, and the intersecting direction of the interdigitated finger electrodes is the same as the elastic wave propagation direction in the other substrate. A liquid crystal device characterized in that interdigitated finger electrodes of each of the substrate and the other substrate are arranged in parallel.