JPS58107516A - Optical switching array - Google Patents

Abstract

PURPOSE:To reduce the capacity between adjacent electrodes, by forming a thin film layer of a low dielectric constant between a dielectric and a signal electrode which forms an optical switching array of a dielectric having an electro-optical effect and set between the polarizers which are orthgonal to each other. CONSTITUTION:A thin film 6 of a low dielectric constant is formed between a PLZT substrate 3 and a signal electrode 4a which is opposite to a common electrode 4b of the plate 3 which is provided between the polarizers which orthogonal to each other. In this case, the tip part of the electrode 4a is deleted. As a result, the electrostatic capacity is reduced between adjacent electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electro-optic shutter using a transparent JT ceramic, especially an optical switching array, which has a plane of polarization parallel or perpendicular to the direction of the array and which does not cause a decrease in switching speed or contrast. Regarding switching arrays.

A ferroelectric material exhibiting a 2'eL electro-optic effect, the so-called Kerr effect, is placed between orthogonal polarizers, and light υ is turned on by applying a voltage. Optical switching arrays that control off are well known.

Ferroelectric material used for such purposes g) P as 1ga
The composition of LZT ceramics is (Pbt -x, Lax l (Zr1-y, T
iy) It is shown by a zero-governing chemical formula, and depending on x and yk, it is 1) 1st order 1.
Since it has a second-order electro-optic effect and an optical memory function, its application to electro-optical public applications such as optical shutters and displays is being studied.

among them,! = 0.086 to 0.1 3' = 035 shows normal crocodile injection at room temperature, but when DC voltage is applied, forced cursing is induced and K becomes so as to show the K@rr effect. Moreover, since it has no memory capacity, it can be applied to optical shutters.
It has a thickness of 1 m and is called a slim loose secondary electrical material.

The basic structure of an optical shutter using this PLZT is 1
As shown in Figure 11, P
An LZT plate 3 is arranged, and a 11-hole 4 is provided to apply a voltage parallel to the plate surface.Then, the plate is arranged so that the direction of voltage application is 45 with the polarization plane of the light incident on the PLZT plate.

If no voltage is applied, the light will be 0 electric [
i! 4. If voltage is applied to the 4゛ gate, the PLZT plate 31)
Refractive index n□ for ordinary light and refractive index n for extraordinary light
e and Δn=n,)-n@=-n3RE2 but n: PLZT2) refractive index R: constant E: causes a difference in applied electric field, optical phase difference p = -, Δn, d λ where d: The ninth polarizer 2 produces an effective thickness of PLZTaθ and the output light generally becomes elliptically polarized light.
The amount of light passing through is 1 = Ii 5in2-Tatashi, 11:PLzTlli, the amount of light incident on the hexagon.

By applying a voltage Vλ/2 such that P=redundant, the passage source L of the polarizer 2 becomes maximum.

An example of configuring a switching play of an optical writing device for an electrophotographic printer using this type of Ker r r effect element is shown in the wXz diagram. In other words, on the PLZT plate 3 placed between the two orthogonal polarizing plates
It is known that the electrodes 4゜4'... of Cr-Au etc. are formed in an interdigital shape (figure a), or the signal electrodes 4&t are arranged in parallel to the common electrode 1fi4b (figure b). It is being In each case, the transmission of light,! ! The area where cutting is controlled is area 5 indicated by diagonal lines in the figure.

However, in Jin's O-light switching television,
In order to improve the resolution, the signal electrodes must be formed in a high density, but this increases the θ capacitance between the electrodes and slows down the switching speed. In addition, electric field leakage to the a-contact signal electrode occurs, resulting in a decrease in contrast. In the present invention, the above-mentioned silent IE shape and electric field leakage occur between adjacent two electrodes.
Considering that the optical switching between the two signal electrodes is increased due to the ferroelectricity of the part that does not have W4 ability, the above disadvantages can be reduced by reducing the amount between the signal electrode and the PLZT substrate. Normally, the signal electrode is made of a metal thin film, and its cross section is flat in both directions. However, for efficiency, parallel electrodes with a circular cross section of radius r are used for a medium with a dielectric constant Er. If calculated for the case where it is placed covering the middle blue gate 1i4d, the capacity of the umbrella length is given by. Therefore, the capacity -C is proportional to the dielectric constant εr of the medium.

Tokoro Te La/Zr/ri = 9/65/35 2)
With the composition, PLZT has approximately εr= at room temperature 1υ0cm
4600, and the capacitance between IEfjjA is quite large in the conventional W structure in which electrodes are directly placed on the PLZT board.
A low dielectric constant thin film 61 is formed between the substrate 3 and the signal electrode 4a except for the tip of the electrode 41. As the material of the membrane, 5i02 (εF=3.5 to 4.0) and polyimide resin (εr=3.4 to 3.S) used in ordinary flexible tape materials can be used. The appropriate thickness of the film is several μm to several tens of μm, taking into consideration the expansion of the electric field in the thickness direction (PLZTll). These thin films are provided over the entire signal electrode portion of the PLZT plate, as shown in FIG. 4, and a pole is formed at 1 so that the tip of the signal electrode 4& is projected thereon.

With this structure, the signal can be transmitted through the capacitance u formed between the capacitors, i'r = 4, d = 125 fim.
2r=5011m, electric+jA'p length l U c
m', and it is possible to prevent negative effects such as electric field leakage, qλ torque, and poor voltage pattern f.

[Brief explanation of the drawing]

@ Figure 1 is an explanatory diagram of the optical switch 0 source 11, Figure 2 is a plan view of the conventional optical switching element υ electrode structure, and Figure 3 is the inventive υ
Cross-sectional diagram of optical switching element tJL3 diagram 4 diagram

Claims (1)

[Claims] An optical switch consisting of mutually orthogonal polarizing elements and a translucent injected electric body having an electro-optic effect arranged between them, and controlling the transmission and blocking of light by applying a voltage to the above-mentioned electric body. In optical switching arrays, the advantage is that a thin film layer with a low placement rate is provided on the signal electrodes and the haze electric body O.