JPS59119319A - Liquid crystal light valve - Google Patents

Abstract

PURPOSE:To obtain a high-resolution, high-quality, and high-speed optical writing unit of simple constitution by charging prescribed liquid crystal between a couple of glass substrates which have four split common signal electrodes and plural signal electrodes. CONSTITUTION:A liquid crystal panel consists of a glass substrate 117 equipped with common signal electrodes 119 and 120, a glass substrate 118 equipped with signal electrodes 121 and 122, a spacer 126, and a liquid crystal composition 125, and has polarizing plates 123 and 124 at right angles. The signal electrodes 121 and 122 are transparent electrodes. Light is modulated at the part of the microshutter consisting of a transparent part 119 and the signal electrodes 121 and 122 and then written. An optical active material is added to cholesteric liquid crystal of >=100kHz in cross frequency for the liquid crystal composition 125 to obtain the high-speed light valve. Thus, the high-resolution, high-quality, and high-speed optical writing operation is performed through the simple constitution by 1/4 time division driving.

Description

[Detailed description of the invention] The present invention relates to a liquid crystal light valve.

Recent advances in information processing technology have been remarkable, and along with this, high-density and high-speed performance are required of printing devices, which are one of the output devices. ζ and others have strong demands for printing quality, and laser beam printers (LBPs) and optical fiber tube (02) printers that use electrophotography and optical writing have been put into practical use as printing devices that satisfy these demands. It has been Z. However, despite strong demands as mentioned in item 1', LBF, 'OF
The fact that both T and T are extremely expensive is a major reason why they have not become popular.

In view of this situation, the present invention was developed using only conventional ideas.
In order to realize the liquid crystal light valve type printing device 6, which has been considered difficult to put into practical use due to various technical problems, we developed a high-resolution, high-quality, high-speed optical V! To provide a small and inexpensive loading unit with a simple configuration.

First, the configuration of the optical unit including the liquid crystal light valve.
As shown in the figure. The optical unit consists of a light source such as a light lamp, a liquid crystal light valve, and an imaging lens 115, and includes a liquid crystal light valve, a liquid crystal panel, 112, and a liquid crystal drive circuit 1i.
Light emitted from seven light sources consisting of a 113FF and 1C substrate 114 is modulated by a liquid crystal light valve. This optical signal 116 is imaged onto the photosensitive drum 102 by the imaging lens 115. An erect image can be obtained by using a focusing optical fiber array as the imaging lens. , Figure 2 and Figure 3 show the horizontal mounting of the liquid crystal panel.
17 and a glass substrate 1 comprising reliable electrodes 121 and 122
A liquid crystal composition 125 is sealed between 18 and a spacer 126, and polarized films 123 and 12 are placed on both sides of the glass substrate.
Be prepared for 4.

The Kyodo Tatami electrode consists of a transparent electrode 119 and an optically opaque metal electrode 120, and the 641M light plates 123 and 124, which are the transparent electrodes of the Shingei electrodes 121 and 122, are arranged so that their polarization planes are orthogonal to each other. . The light is modulated by the micro-shutter formed by the transparent portion 119 of the common electrode and the signal electrode. Patent application filed in 1984 as a liquid crystal paraboloid
-14'1085 Optically active substances in the liquid crystals shown in Table 1
Ji 4-(2-methylbulyl)-4'
-cyan.

A high-speed liquid crystal light valve can be obtained by using a long-period cholesteric liquid crystal obtained by adding 6 parts by weight of -bip, henyls. The frequency characteristic of the line potential sotropy of this liquid crystal is shown in Fig. fy4.

The frequency at which the dielectric anisotropy is zero is called the differential frequency fc
It is expressed as The frequency lower than fc is fL, the higher frequency ff
Let it be H. The liquid crystal light valve operates by applying frequencies of fL and fH to each signal electrode. Figure 5 (b) is applied to Shingei and (a)! This shows the response of light transmitted through a crystal light bulb.

A signal at time fH indicated by T2 and a signal at time fL at T6 are applied. A cycle that incorporates T1.

T2 is the opening time, T6? It is called Shima, which is not open to the public. By applying the fH signal, the liquid crystal light 1 bulb opens, and the fL
With this confidence, we were able to obtain a revolutionary high-speed liquid crystal light valve using the method described above. However, in order to print a high-quality seal, it is necessary to arrange microshutters at a high density of about 10 per hole, and they are lined up in a width of 20ctn on the 1ζ scale to be printed on an A4 plate. Therefore, in the method described above, there are 2,000 signal electrodes and 2,000 drive circuits and their mounting terminals.
The disadvantage was that the wood was too thin, the manufacturing yield was low, and the cost was high.

Therefore, time-division driving has been proposed in order to reduce costs, and the present invention provides a liquid crystal panel for realizing μ time-division driving.

Amazu 174UFP split driving method will be briefly described. Figure 6 1. FIG. 7 shows the V4 time-division electrodes and drive waveforms.C selection signals 22i, 222°223.224f are applied to the four common electrodes 201, 202, 203°204, respectively, and writing is performed on the signal electrode 205. An open signal 225 or a close signal 226 is applied depending on the data. At this time, the selection signals 221 to 224 and the open signal 2251 close signal 226 (l- are in opposite phases to each other. T1 is the sub-scanning period, Ta selection period, Til"i:1IliF selection period, and the micro shutter 211 to 214 selection signals 221~
It opens and closes in response to the signal applied to the signal electrode during the selection period of 224, and remains closed during the non-selection period. This situation is shown in Part 8. When a signal like 235 is applied to the signal electrode 205, the optical response of each micro-shutter 211214 is 231.
~264. As described above, by realizing μ time-division driving, a significant cost reduction was achieved.

However, as the number of time divisions increases, the number of signal electrodes decreases, but the shape of the electrodes tends to become more complex. This is because in a liquid crystal light valve, any light leakage from any part other than the microshutter is unacceptable because it will reduce the contrast.

(However, as shown in FIG. 6, light leakage always occurs in the gaps between the common electrodes and the gaps between the signal electrodes.

The question is how to make this small in practical terms.

This is one point.

The maximum ratio between the second and second microshutters is 1171 (6th
In the figure, the distance between 211 and 214 in the vertical direction) is.

Limited to a focusing fiber play for use as an imaging lens. This is because when line scanning is performed as in the present invention, the amount of light in the image decreases significantly when the focusing fiber lens array deviates from the optical axis by more than a certain distance.

Furthermore, in general, in the case of fine turns with a large Ifi product as in the present invention, the ease of alignment and the margin surface greatly affect the yield t.

FIG. 9 shows the electrode pattern of a liquid crystal panel according to the present invention, which was manufactured with the above considerations in mind. (a) Id is a common electrode completely formed on the first glass, and is divided into six parts. The common electrodes 201 to 204 to which selection signals are applied are dummy electrodes 301 and 302, each having a width of 1. In each common electrode, the portions of the microshutters 211 to 214 are transparent electrodes, and the remaining hatched portions are made of opaque Ni% metal electrodes.

Pitch of micro-shutters arranged in a staggered pattern P1 to 10
0μm, microshutter pressure is /'s (
211-212) is 25 μm.

/5 (between 211213) is 450μm-es (211
-214) is 475 μm. This is a condition for the number of dots that are intersected by time-division driving to form a straight line in the half-time direction - sub-scanning period + T1. Photoconductor moving speed y
When v, the interval between the microshutters 'RFse=
(-+n)XTV (tn=1゜2.6・n=+0+
1+2...) is satisfied. However, T = 2 mx,
V = 5 cm/stx.

Next, (b) shows the secret area embossed on the glass of v.2, where the shaded area of the signal electrode 205 is made of a metal film and is opaque.
The other part 611 is a transparent electrode. Pin between electrode terminals
Pg ilt 400 prn f, 20σT When mounting on a 6-driver E-C with 500 wires, the pitch is 400 μm, so it will not take much effort, but if the signal electrode terminals are arranged interdigitally, the pitch on one side will be 8.
00μm Tofx Li.

Furthermore, it is easy to implement.

FIG. 10 shows the above two glasses stacked together. Since the surfaces with electrodes are stacked on top of each other, it should actually be 9.
Either (a) or (b) of the figure is a sharp image.

As shown in No. 10 and 1 (the shaded areas are all opaque, the light incident on the liquid crystal panel is transmitted to the micro shutter 21).
1 to 214, the optical write signal arrives. Furthermore, since light always leaks from the light leakage portions 421 to 624, this results in an offset from the perspective of an optical signal. Therefore, since this offset varies among the microshutters, the light leakage portions 321 to 624 are arranged so as to correspond one-to-one with the microshutters 211 to 214. On the other hand, the amount of this offset can be adjusted in practical terms. In order to keep it to a non-problematic level, the size of the light leakage part should be 10 μm x the total minimum line width.
It was set to 10 μm. In fact, if the size of the microshutter is 100 μm x 90 pm, this amount of leakage will be calculated even if the amount of leakage is reduced by %.

There are too many people in charge 4. On the other hand, in consideration of manufacturing yield, in order to minimize the total length of the minimum line width, the optical d1i
With the electrode shape of the liquid crystal panel according to the present invention as described above, the line width is minimized only in the vicinity of the part where the distortion occurs.
We were able to create a μ time division driven liquid crystal panel. We were able to construct a liquid crystal light valve that can provide a high-performance, low-cost optical unit.

[Brief explanation of drawings]

Figure 1 shows the origin of the light book superstition. Figure 2, bamboo grass 3 is 4
The structure of the crystal panel is shown. ]ゝ:4- is one showing the frequency convergence characteristics of the dielectric anisotropy of the liquid crystal material used in the present invention. The fifth section is a diagram showing the response characteristics of the liquid crystal material used in the present invention and the driving signal at that time. Figures 6 and 7 show the principle diagram and drive waveform of the rl'iV4 clear split electrode structure. Figure 8 shows the optical response and drive waveform of each microshutter during % time control and excitation. Ta. FIGS. 9(a) and 1(b) show the electrode shapes of the first glass and the second glass of the liquid crystal panel according to the present invention. Two pieces of glass in the 10th house 1? The shape of the electrode at the time of one stack is shown. 201-204... Common electrical connection 205... Shingei-ku pole 211-214... Micro shutter 321
~624...Light leakage Figure 2 Figure 3 Figure 5 Figure 6 Figure 7
To 3゜I Fig. '9 3 S λ Fig. 10

Claims (1)

[Scope of Claims] ■ In a liquid crystal light valve with a time division of μ, a 7pi crystal panel has a first glass having a common electrode divided into at least four parts and a common electrode having a common electrode divided into at least four parts. consisting of a second glass having a plurality of contact electrodes, each of which has an opaque portion that intersects with the gap;
Part 1. The second glasses are arranged so as to cross each other, and between them, an optically active material is added to a nematic liquid crystal whose cross frequency fc at which the anisotropy reaches zero is 100 KH2 or more and which is lightning-resistant at a temperature of 100 KH2. A liquid crystal light valve characterized by being completely filled with liquid crystal material F-4. ■ In the liquid crystal panel, the micro-shutters arranged in a staggered manner by the common electrode and the signal electrode are arranged in a staggered manner, and the interval between them is as follows: ( −+n ) XTI XV (m
=11 21 3eH, =Q, 11 2...) A liquid crystal light valve as set forth in claim 1. ■ Light leakage outside the micro-shutter clothing
ft d" is smaller than the Micro 7 Yator. Claim 1, characterized in that the micro shutter and the light leakage portion correspond one to one.○
LCD light bulb. (2) The liquid crystal light valve according to claim 1, wherein the electrical failure pattern at least near the light leakage portion has the minimum line width of the liquid crystal panel.