JPS6026927A - Optical control element - Google Patents

Abstract

PURPOSE:To obtain an element which can prevent surely light leakage from a shutter part and has high resolving power by covering the circumference in the prescribed part between the counter electrode pairs formed on a transparent base plate having an electrooptic effect with a thin film mask which has an insulating characteristic and shields visible light and providing a pair of polarizing plates which sandwich the transparent base plate formed with such electrodes and mask. CONSTITUTION:A common electrode 11 is formed on a PLZT flat plate 10 by a photolithography method and electrode groups 12 for impressing voltage are likewise provided thereto by a photolithography method. A thin film mask 13 used to prevent leakage of light and to allow passage of light only through the required part consists of any one among amorphous silicon, amorphous germanium and amorphous gallium arsenide and has an insulating characteristic and the property to prohibit transmission of visible light. If a voltage is impressed to the electrode (b) among the electrode groups 12 when light is irradiated to said element from a light source 16 provided behind a polarizer 14, the light is transmitted only through the required shutter part by the mask 13 and therefore >=10 line/mm. resolution is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to an optical control element that is used in various optical information processing devices and continuously controls optical signals.

Conventional Structure and Problems There has been remarkable progress in the field of information processing technology in recent years. Under these circumstances, the role of printers as information output devices is becoming increasingly important. Currently, various types of printers are being developed, but the one that is attracting the most attention is the non-impact printer. (optical shutter element) is attracting attention. Conventionally known such light control elements include La
A substrate with a plurality of strip electrodes provided on at least one side is placed on a flat plate of translucent porcelain such as doped lead zirconate titanate (PLzT) in the direction of the electric field vector generated when a voltage is applied to the strip electrodes. On the other hand, it has a structure in which it is sandwiched between polarizing plates having polarization axes of ±45°. Such a conventional light control element will be explained using FIG. 1. 1st
Figure (3) is an exploded perspective view of a conventional light control element, where (1) is a P L Z T flat plate, 2) is a gate, a common electrode provided on the ZT flat plate (1), and (3) is a voltage Group of electrodes for application, (4
) is part of the optical shutter. (5) is a polarizing element, (6)
is an analyzer, and the common electrode (2) and the H earth pressure applying electrode #
(a) and is configured to have a deflection axis in a direction of ±45° with respect to the direction of an electric field vector generated when a voltage is applied between it and (a). (υ is the light source. Figure 1 is an explanatory diagram of the operating state of the light shutter part (4) of the light control element.
(8) shows the operating part (theoretical shutter part), and (9) shows the light transmitting part of the optical shutter part (4) during actual operation.

When irradiated with light from a light source (7) with a wavelength of 5400A provided at the rear of the polarizer (5), the PLZT flat plate (
1) When V<pressure is not applied between the voltage applying electrode group (3) formed above and the common electrode (2), birefringence due to the electro-optic effect does not occur, and the polarizer (5) and Analyzer (6
), but the voltage application electrode ff18
When a voltage is applied to (3), birefringence occurs due to the electro-optic effect, the polarization state of the light changes, and a part of the optical shutter (4
), the light is transmitted through it. Therefore, the voltage application electrode group (3
) can transmit light from any part by applying a voltage to any electrode, and by placing a photoreceptor etc. in front of the analyzer (6), it is possible to display any pattern. This is the writing of a non-impact optical printer.
Can be used as a rad.

Incidentally, the writing heads currently used in printers are required to have a resolution of at least 10 lines per line, and when using the above-mentioned solid-state optical shutter array, a long light beam of 200 lines or more is required. Shutter・＼
Rad is required. However, if the electrode structure is as shown in Figure 1 (A), as shown in @ Figure 1 (B),
Since the electric field is applied to areas other than the active part (8), light leakage occurs, resulting in a transparent part (9), making it impossible to write a high-resolution pattern on the photoreceptor.

As a way to eliminate this drawback, a transparent insulator (glass, SiO2,
AI! It is considered that a metal thin film mask may be provided via a mask (such as 208). However, the light control element of 2QQ14N has as many as 2,000 electrodes, for example, 10 lines per line.In the so-called Sanderuch type electrode structure, which has a metal mask on top through a thin insulating film, there is not even one electrode. It is very difficult to make devices without pinholes.

Furthermore, even if a metal mask is attached with adhesive, there is a problem of the adhesive protruding, and it is also difficult to attach a mask of 200 or more to the part of the optical shutter (4) with good positional accuracy.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to provide a high-resolution light control element that can reliably prevent light leakage from a part of the light shutter.

Structure of the Invention In order to achieve the above object, the light 87! of the present invention! The I element includes a transparent substrate having an electro-optical effect, a pair of opposing electrodes formed on this transparent substrate, and an insulating property that covers the periphery of a predetermined portion between the opposing polarized pairs and blocks visible light. This configuration includes a thin film mask, and a pair of polarizing plates that sandwich the transparent substrate on which the thin film mask and a pair of opposing electrodes are formed.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Figure 2 is an exploded perspective view of the light control element.
LZT flat plate, cll) is PLZT flat plate 01 upper near, t
Common electrode provided by triregraphy method, (2
) is a voltage application electrode group also provided by the photophosphorography method. Ql is a thin film mask that prevents light leakage and allows light to pass only where necessary. It is made of one of amorphous silicon, amorphous germanium, or amorphous gallium arsenide, and is insulating and allows visible light to pass through. It has the property of not having. α4 is a polarizer, 0υ is an analyzer, and H is a light source.

When light is irradiated from the light source oQ provided at the rear of the polarizer α, the voltage application electrode! When a voltage is applied to 1 Oa, birefringence occurs due to the electro-optic effect, and light in that area is transmitted.

@8 Figure (A) is an explanatory diagram of the operation using the conventional electrode structure.
FIG. 8 (□□□ is an explanatory diagram of the operation of the electrode structure provided with a mask according to this embodiment. For example, in the conventional configuration,
When 1u pressure is applied to electrode (a) of the voltage application electrode group (3), the vector of the tu field is not necessarily perpendicular to the common electrode (2) and is 4r, so light is generated as shown by the diagonal line in the figure. It's easy to see through. On the other hand, in the configuration of the embodiment, if a voltage is applied to the electrode (1) of the voltage application electric image Y404, only the part of the shutter (the dot part in the figure) required for thin film mask θ is exposed. To Penetrate.

In this way, the conventional light control element at 11°C has a large amount of light leakage, and it is difficult to obtain a resolution of 1 (1 line/frame) or higher due to the 2'A of light. However, in this example, the light is transmitted only where it is needed, so 10 lines/
You can get the resolution of "fighting".

FIG. 4 is a schematic perspective view when the light control element according to an embodiment of the present invention is used as a hooking head of an optical printer, where 07) is a photosensitive drum, θ Eno is a SELFOC 1/
In the lens array, ol is a light control element.

Fi4. The light from the optical gap oQ having a wavelength of ooA is transmitted only in a specific part 7 by the light control element 0.
The transmitted light is imaged by the SELFOC lens array (g) onto the surface of the photoreceptor drum (b). Therefore, with such a configuration, printing with high resolution becomes possible, as can be seen from FIG. 3(B).

In addition, in the above embodiment, the voltage application electrode H#aS
z (ilil total width 0 μm, voltage application electrode group 0
The electrode interval between the tower and the common electrode αυ was set to 30 μm.

Further, to form electrode 0 (6), gold was deposited by sputtering. Amorphous silicon (α-5i) and amorphous germanium (α-Ge) as materials for masks
) and amorphous gallium arsenide (α-GaAs) were all produced by sputtering. In the case of these mask materials, since a highly insulating film cannot be obtained by sputtering normally performed in argon gas, 5 to 10% hydrogen is added.
Sputtering is performed using argon gas as a sputtering gas, and as a result, α-5i is formed with a film thickness of approximately 1 μm.
1012 Ωcm, (1!-109 Ω・c in Ge
An insulating film of 1010 Ω/sol was obtained using ln, α-GaAs, and the transmittance of all visible light of 600 nm or less was suppressed to 0.1% or less.

As described above, according to this embodiment, not only can writing be performed with much better resolution than when writing is performed on an optical printer without forming a mask on the light control element as in the past, but also It is now possible to mask directly on the electrode without using an insulator layer, reducing the number of man-hours and increasing the
Even devices with a length of 0 mm or more can be manufactured without the problem of pinholes, and are also useful for improving yield.

As described in detail, according to the present invention, it is possible to improve the resolution, reduce the number of steps for manufacturing elements, and improve the yield.

[Brief explanation of drawings]

Figure 1 (A) is an exploded perspective view of a conventional light control element;
B) is an explanatory diagram of the operation of the light control element, FIG. 2 is an exploded perspective view of the light control element in one embodiment of the present invention, and FIG. 8(A)
4 is a front view of an electrode structure of a conventional light control element, FIG. 4B is a front view of an electrode structure of a light control element according to an embodiment of the present invention, and FIG. 1 is a perspective view of an optical printer using 01... PLZT flat plate (transparent substrate), 0υ... common electrode (counter electrode pair), aa... voltage application electrode (counter electrode pair), 04... thin film mask, (141... threshold voltage (Polarizing plate), (15°゛ Analyzer (Polarizing plate) Agent Yoshihiro MorimotoFigure 7 (A) (β) Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A transparent substrate having an electro-optic effect, a pair of opposing electrodes formed on the transparent substrate, and having an insulating property that covers the periphery of a predetermined portion between the pair of opposing electrodes, and a visible light source. A light control element comprising: a thin film mask that blocks light; and a pair of polarizing plates that sandwich the transparent substrate on which the thin film mask and a pair of opposing electrodes are formed. 2. The light control element according to claim 1, wherein amorphous silicon is used as the thin film mask. 8. The light control element according to claim 1, wherein amorphous germanium is used as the thin film mask. 4. The light control element according to claim 1, wherein amorphous gallium arsenide is used as the thin film mask.