JPH01179015A - Light valve device - Google Patents

Abstract

PURPOSE:To facilitate a manufacture process and to improve the yield by fitting an electrode to a semiconductor layer. CONSTITUTION:A transparent substrate 11, a transparent conductive layer 12, a semiconductor layer 13, the electrode 19, a light shield layer 14, a mirror 15, a dielectric layer 16, a transparent conductive layer 17, and a transparent substrate 18 are laminated in order. The electrode 19 is a high-barrier electrode which forms a Schottky junction with the semiconductor layer 13 and made of a material with good adhesive strength to the semiconductor layer 13, e.g. Pt, Au, etc., and arranged on the semiconductor layer 13 in a grating shape. When a specific electrode is applied to the electrode 19, charges are removed from the part of the semiconductor layer 13 right below the electrode. Consequently, even when the resistivity of the semiconductor layer is small, the diffusion of charges are precluded, so the resolution is prevented from decreasing, the manufacture process is easy, and the structure which is suitable for good- yield, large-area formation is obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is used in optical arithmetic circuits, etc., and applies a predetermined driving voltage dividedly to a dielectric layer and a semiconductor layer that have an electro-optic effect, and The present invention relates to a light valve device that modulates and outputs read light by changing the state of a dielectric layer by changing the voltage of a semiconductor layer due to incoming light.

[Conventional technology]

Conventionally, a structure as shown in FIG. 4 is known as a light valve device.

In FIG. 4, the light valve device 50 includes a transparent substrate 51
．． Transparent type [152, semiconductor layer 53. A mirror 55, a dielectric layer 56 having an electro-optic effect. Transparent electrode 57. Transparent substrates 58 are sequentially laminated. semiconductor layer 53
A p-type (or n-type) semiconductor material 1, such as silicon, having a low impurity concentration is used for the. A p-type region 61 with a high impurity concentration is formed in a planar shape on the transparent electrode 52 side of the semiconductor layer 53, and an n-type (or p-type) region 61 of a conductivity type different from that of the semiconductor layer 53 is formed on the dielectric layer 56 side. area 59
are formed in an island-like (or lattice-like) pattern with predetermined intervals, and the region 59 and the semiconductor layer 53 form a pn junction microdiode, and the region 61 and the semiconductor layer 53 form a planar pn junction. It has become.

In such a light valve device f50, in the case of AC drive, a driving voltage is applied between the transparent electrodes 52 and 57 by the AC power supply 60. When the writing light WL is not incident, the driving voltage is applied to the semiconductor layer. 53, light shielding layer 54. mirror 55
．． A voltage is applied to each of the dielectric layers 56 according to these impedances. At this time, the voltage applied to the dielectric layer 56 is below a predetermined threshold value, and the dielectric layer 56 is in an off state. When the writing light WL is incident on the semiconductor layer 53, charges are generated in the irradiated portion of the semiconductor layer 53, and the charges are distributed so as to reduce the voltage applied to the irradiated portion. The voltage at the corresponding portion of the dielectric 156 increases to a predetermined threshold value or higher, and the dielectric layer 56 is turned on.

By the way, when a reverse bias is applied to the pn junction microdiode formed in the semiconductor layer 53, a depletion layer extends from a portion directly below the region 59 in the semiconductor layer 53 toward the transparent electrode 52 to the region 61. Alternatively, the depletion layer extends from directly below the region 59 forming the planar pn junction toward the dielectric layer 56 until it reaches the pn junction microdiode in the region 59. This depletion layer functions to exclude charges from the lattice-shaped p-type portion of the p-n junction microdiode, so it prevents the charges generated in the irradiated portion of the semiconductor layer 53 from diffusing in the lateral direction. High resolution can be maintained by preventing voltage changes in a predetermined portion of the semiconductor layer 53 from crosstalking with voltage changes in adjacent portions. This high resolution, that is, high resolution characteristics is also reflected in the dielectric layer 56.

Therefore, the readout light RL is transmitted to the transparent substrate 58. When the light enters the dielectric layer 56 through the transparent electrode 57, is modulated by the change in state of the dielectric layer 56, and is output, the modulated read light can have high resolution.

For example, when the writing light WL has two-dimensional information,
A high-resolution two-dimensional image can be obtained using the readout light RL.

[Problem that the invention seeks to solve]

However, in the light valve device 50 described above, since the region 59 is formed in the semiconductor layer 53 to create a pn junction microdiode, there is a problem in that it is difficult to manufacture a device with a high yield and a large area.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light valve device having an easy manufacturing process and a structure suitable for manufacturing a large-area device with high yield.

A further object of the present invention is to provide a light valve device having a structure that allows controls such as reset and image control to be performed independently of drive voltage and writing light.

[Means for solving problems]

In the present invention, a predetermined driving voltage is dividedly applied to a semiconductor layer and a dielectric layer having an electro-optical effect, and the state of the dielectric layer is changed by the voltage change in the semiconductor layer caused by the write light, thereby modulating the read light. The above-mentioned problems of the prior art are improved by a light valve device of this type, characterized in that electrodes arranged in a predetermined pattern are attached to the semiconductor layer.

[Effect]

In the present invention, electrodes with a predetermined pattern arrangement are attached to the semiconductor layer. When a predetermined voltage is applied to this electrode, charges are removed from the portion of the semiconductor layer directly below the electrode. This makes it possible to prevent charge diffusion even if the resistivity of the semiconductor layer is small, thereby preventing a decrease in resolution.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram of a first embodiment of a light valve device according to the present invention.

The light valve device 1 of the first embodiment includes a transparent substrate 11.
Transparent conductive layer 12. Semiconductor layer 13. Electrode 19, light shielding layer 14
．． Mirror 15. Dielectric layer 16° transparent conductive layer 17. Transparent substrates 18 are sequentially laminated.

The semiconductor layer 13 may be formed of a single semiconductor material, or may have a photodiode-like structure consisting of a p-type layer and an n-type layer. When the semiconductor material 1 is not amorphous but is made of single crystal semiconductor material 1, for example, single crystal silicon, its resistivity is generally low.

The electrode 19 is a high-barrier material that forms a Schottky junction with the semiconductor layer 13 and is made of a material 1 having good adhesion to the semiconductor layer 13, such as Pt or A. They are arranged in a grid pattern. The electrode 19 has
An AC voltage having a predetermined frequency and voltage value corresponding to the driving voltage of the AC power source 60 is applied from the AC power source 27 .

Further, the dielectric layer 16 is made of a material having an electro-optic effect, such as liquid crystal.

In the light valve device 1 having such a configuration, the AC power source 6
The driving voltage from 0 to the semiconductor layer 13. Light shielding layer 14. Mirror 15. When the writing light WL is made incident on the semiconductor layer 13 with a partial voltage applied to each of the dielectric layers 16, the irradiated portions of the semiconductor layer 13.

For example, charges are generated at 13a. This charge is the irradiated part 1
Since the voltage applied to the dielectric layer 16 is distributed so as to decrease the voltage applied to the dielectric layer 13a, the voltage of the portion 16a of the dielectric layer 16 corresponding to the irradiated portion 13a increases and exceeds a predetermined threshold value, and the voltage applied to the dielectric layer 1
6, that is, the liquid crystal is turned on and the readout light RL can be modulated.

By the way, when an AC voltage from the AC power supply 27 is applied to the electrode 19 and a reverse bias is applied to the Schottky junction between the semiconductor layer 13 and the electrode 19, the semiconductor layer 1 surrounded by the electrode 19
Dielectric layer 16ffl on portions 13a, 13b, etc. of 3! Since an equipotential surface such that I is the deepest well is formed in the semiconductor layer 13, the portions 22a, 22b,
Charges are removed from directly under the electrode 19 such as 22c, and the portion 1
It is possible to prevent charges such as 3a113b from spreading in the lateral direction and causing crosstalk. Especially the semiconductor layer 13
When the resistivity is low, charges tend to diffuse laterally, so this can be effectively prevented.

Therefore, the portion 1 of the semiconductor layer 13 caused by the incidence of the writing light WL
The voltage change of the portion 3a has little influence on the voltage change of the adjacent portion 13b, and it is possible to prevent a decrease in resolution and maintain high resolution characteristics.

This high-resolution characteristic is also reflected in the dielectric layer 16, and it becomes possible to give the readout light RL modulated by the state change of the dielectric layer 16 a high-resolution characteristic.

The light valve device 1 having the structure as described above is produced by the following manufacturing process.

First, a transparent conductive layer 12 is deposited on a transparent substrate 11, and a planar semiconductor layer 13 is laminated thereon. After forming the semiconductor layer 13, electrodes 19 are formed in a predetermined pattern arrangement, for example, in a lattice shape, using a lift-off method or etching, and then a light shielding layer 14 and a mirror 15 are sequentially formed. FIG. 2 shows the grid-like electrodes w119 and the light-shielding layer 14 formed in this way.
The transparent conductive layer 17 on NJ16.8 and the mirror 15 form a dielectric NJ16.8. For example, glue the liquid crystal in between.

In this way, according to the first embodiment, the electrode 19 is formed after the semiconductor layer 13 is formed, so compared to the case where the region 59 is formed in the semiconductor layer 53 as shown in FIG. , the manufacturing process becomes easier and the yield can be improved. In addition, large-area products can be easily manufactured.

FIG. 3 is a partial configuration diagram of a second embodiment of the light valve device according to the present invention.

In the light valve device 30 of the second embodiment, the electrode 21 is formed on the semiconductor Vk layer 13 via the insulator layer 2o, and the MIS
I try to make it I-built. The electrode 21 is an insulator layer 20
It is made of a metal that has good adhesion to the substrate, and is formed in a desired pattern arrangement using the lift-off method or etching.

Even with such MIS remains, it is possible to effectively prevent charge diffusion and maintain high resolution characteristics, similar to the Schottky junction described above. Also, similar to the first embodiment, there are advantages such as easy manufacturing process and good yield.

Furthermore, the above 1. The electrodes 41i19. forming a Schottky junction in the second embodiment. Or M■S structure! [
By appropriately controlling the magnitude, polarity, etc. of the voltage applied to 721, the state of the light valve device 1.30 can be changed independently of the drive voltage of the AC power supply 60 and the writing light WL. , if you want to erase the information of the write light WL and reset the light valve device 1.30, use tl
You can change the magnitude or polarity of the voltage applied to i19゜21 and apply it to promote charge diffusion.
9. By controlling the voltage applied to 21, it is possible to output an image for any suitable time.6For example, if the writing light WL is a moving image, it is possible to easily output only the image at any given time. can. At this time, if a material having a memory effect (for example, a ferroelectric crystal) is used as the dielectric layer 16, images can be stored, and by repeating this process, arbitrary images can be superimposed and stored.

In addition, in the above-mentioned embodiment, the light shielding layer 14 is a mirror 15.
It is provided to prevent the reading light RL transmitted through the electrodes 19. from entering the semiconductor layer 13, and is not necessary if the reading light RL can be completely reflected by the mirror 15. After forming 21, mirror 15
so that it forms.

[Effects of the Invention] As explained above, according to the present invention, since the structure is such that the electrode is attached to the semiconductor layer, the manufacturing process is easier and the yield can be improved compared to the conventional light valve device. can. Furthermore, since it is a Schottky junction and MIS top structure, the driving voltage.

The light valve device can be controlled independently of the writing light.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of a light valve device according to the present invention, FIG. 2 is a diagram showing a grid-shaped electrode and a light shielding layer,
FIG. 3 is a partial block diagram of a second embodiment of the light valve device according to the present invention, and FIG. 4 is a block diagram of a conventional light valve device. 1.30... Light valve device, 13... Semiconductor layer, 16... Dielectric layer, 19.21... Electrode, 20...
...Insulator layer patent applicant Hamamatsu Photonics Co., Ltd. Agent Patent attorney Masaharu Uemoto Figure 4'RL

Claims (1)

[Claims] 1) A predetermined driving voltage is applied as a divided voltage to a semiconductor layer and a dielectric layer having an electro-optic effect, and the state of the dielectric layer is changed by the voltage change of the semiconductor layer caused by writing light. 1. A light valve device of a type that modulates readout light, characterized in that electrodes arranged in a predetermined pattern are attached to the semiconductor layer. 2) The light valve device according to claim 1, wherein the electrode is attached directly to the semiconductor layer to form a Schottky junction with the semiconductor layer. 3) The light according to claim 1, wherein the electrode is attached to the semiconductor layer via an insulator layer, and the semiconductor layer and the insulator layer form an MIS structure. Valve device.