JPS6338690B2 - - Google Patents

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to the structure of a liquid crystal light valve.

[Prior art]

Now, in recent years, the prices of CPUs, memory, etc. have been decreasing due to advances in semiconductor technology, and the people who use microcomputers and office computers, and those who come into contact with computer printouts, are limited to those who are specialized in conventional EDPS. Since then, it has been spreading widely to the general public. In other words, there is a growing desire for output processing at the same level as for ordinary documents, that is, output in kanji and kana characters. One typical example would be a Japanese word processor.

However, as mentioned above, the prices of circuits and memory for such systems are steadily decreasing, and we can expect them to continue in the future, but the printers that serve as the output terminals, assuming the use of kanji, etc. Since a resolution of about 32 x 32 dots is required, it is necessary to have a high resolution and a high speed that can cope with the decrease in printing speed due to higher resolution. This has led to an increase in costs.

For example, currently there are only optical printers that use lasers, OFT, and multi-stylus electrostatic printers that can meet this requirement, but both are extremely expensive and are the biggest factor driving up system costs. There is.

Therefore, the spread of various systems such as those mentioned above in the market has been slow (despite market needs).
This is a major hindrance.

The above situation is basically the same for high-speed facsimile machines, CRT hard copy machines, various terminals, etc.

Therefore, in the past, printing devices using liquid crystal light valves have been considered. For example, British Patent No. 1308208 describes image formation using a liquid crystal shutter.

FIG. 2 is a diagram showing a simple electrode configuration of a liquid crystal light valve. 21 and 22 are electrodes 2, respectively.
3 and 25, and there is a liquid crystal layer between these two glass substrates. electrodes 23 and 25
By applying a voltage between them, a minute shutter in the weighted portion opens and closes. However, light always passes through the area other than this heavy part.

The light valve used in this printing device must not transmit light except for the minute shutter portion. There are two ways to solve this problem. One method is to arrange the polarizing plates in parallel instead of using them orthogonally as described above. Another method is to cover the area without electrodes with an opaque material. The former has serious drawbacks. This is because when liquid crystal molecules are not perfectly twisted and aligned, light passes through them. What a light valve needs to do is completely shut off the light. Therefore, in order to satisfy this requirement, the polarizing plates must be arranged perpendicularly to each other. The latter method is effective in this case.

Conventionally, the structure of a liquid crystal light valve used in such a printing device is disclosed in U.S. Pat. No. 3,622,226.
The structure seen in the issue was there. In this structure, a liquid crystal is inserted between a pair of transparent substrates, and a common electrode and a signal electrode are formed on each substrate.
The overlapping region of the common electrode and the signal electrode serves as a window. The liquid crystal transmits or blocks external incident light by responding to the application of a common electrode signal to the common electrode and the selection signal to the signal electrode. If light is transmitted through the liquid crystal light valve other than the above-mentioned window, it will not function as an original liquid crystal light valve, so a light shielding plate must be provided in that area. Nakatsuta.

However, in such a structure, it is necessary to take the trouble to provide a light shielding plate on the outside of the transparent substrate, and in order to obtain a complete shielding effect, the alignment with the window must be performed precisely. Furthermore, since it requires adhesion to a transparent substrate, there is a problem of complicating the process.

〔the purpose〕

The present invention overcomes the above problems, and
By providing a common electrode with a light shielding function, the manufacturing process can be simplified and a liquid crystal light valve with a simple structure can be provided.

〔Example〕

Electrode diagrams of an embodiment of the present invention are shown in FIGS. 1a and 1b. 21 and 22 constitute the liquid crystal light valve.
It is a glass substrate. 21 is a glass substrate provided with a common electrode, and 22 is a glass substrate provided with a plurality of independent electrodes. A light valve is constructed by placing substrates 21 and 22 facing each other and sandwiching a liquid crystal layer therebetween. Reference numerals 23 and 25 are electrodes made of transparent conductive films such as indium oxide, and the overlapped portions serve as minute shutters. 24 and 2
6 is an opaque metal electrode made of a chromium-gold vapor deposited film or the like.

This metal electrode can prevent transmission of light other than the minute shutter portion. Furthermore, the metal electrode can reduce wiring resistance.

The drive signal used in the present invention includes a high frequency as described above. Therefore, it is necessary to minimize the rounding of the waveform of the drive signal, and for this purpose, it is a necessary condition that the wiring resistance is small. Using metal electrodes in this way has two effects: preventing light transmission and reducing wiring resistance. By using the method described above, it was possible to obtain a liquid crystal light valve with extremely excellent response characteristics.

Furthermore, not all of the emitted energy from the light source 1 is effective, and especially in the ultraviolet region, it can damage the polarizing plate of the liquid crystal light valve 2 and ultimately eliminate its effect, as well as have a negative impact on the liquid crystal itself. On the other hand, since the infrared region uses thermal energy to heat the liquid crystal and the polarizing plate, there is a problem in that it becomes difficult to control the temperature of the liquid crystal, as described above. Therefore, it is most convenient to use a light source that contains almost no infrared or ultraviolet light.

〔effect〕

As described above, in the present invention, a liquid crystal is inserted between a pair of opposing transparent substrates, a common electrode having a plurality of windows is formed on the first transparent substrate, and a common electrode corresponding to the windows is formed on the second transparent substrate. In a liquid crystal light valve consisting of a plurality of signal electrodes, the common electrode consists of a window made of a transparent conductive film and a conductive region other than the window made of an opaque metal conductive film, and the signal electrode is connected to the window made of the transparent conductive film. Since the structure consists of a corresponding area and an extraction electrode, it is possible to completely prevent light from passing through, except for the window part, regardless of whether or not a voltage is applied to the liquid crystal, and the electrode has the function of light shielding and voltage application. Can be used for both purposes. Therefore, a liquid crystal light valve with a simple structure can be obtained. In addition, opaque metal conductive films have lower wiring resistance than transparent conductive films,
Therefore, the distortion of the signal applied to the transparent conductive film can be minimized.

[Brief explanation of drawings]

FIGS. 1a and 1b are diagrams showing an embodiment of the liquid crystal light valve of the present invention. FIG. 2 is a diagram showing an example of the structure of a conventional crystal light valve. 21, 22... Glass substrate, 23, 25... Transparent electrode, 24, 26... Opaque metal electrode.

Claims (1)

[Claims] 1. A liquid crystal is inserted between a pair of opposing transparent substrates, a common electrode having a plurality of windows on the first transparent substrate, and a common electrode corresponding to the windows on the second transparent substrate. In a liquid crystal light valve consisting of multiple signal electrodes,
The common electrode consists of a window made of a transparent conductive film and a conductive region other than the window made of at least an opaque metal conductive film, and the signal electrode consists of a region corresponding to the window made of a transparent conductive film and an extraction electrode. A liquid crystal light bulb featuring: 2. The liquid crystal light valve according to claim 1, wherein the conductive area other than the window and the extraction electrode are opaque conductive films.