JPH06235892A - Optical shutter array element - Google Patents

Abstract

(57) [Abstract] [Purpose] Due to the curing shrinkage of the adhesive that joins the transparent electro-optical ceramic individual elements arranged in an array and the insulating substrates placed on both sides, (EN) Provided is an assembly structure of an optical shutter array element in which unnecessary light leakage due to a generated photoelastic effect is prevented and a contrast ratio is improved. [Structure] Individual elements 6 made of transparent electro-optical ceramics arranged in an array at a constant pitch, film electrodes 2 and 3 formed on both side surfaces of each individual element, and on the electrode surface sandwiching the individual elements. In the optical shutter array element, which is composed of an insulating substrate 7 which is superposed and bonded with an adhesive 8 and lead leads 9 and 10 which are formed by patterning on the insulating substrate by connecting one end to an electrode of each individual element, A light-shielding layer is formed by patterning the leads further inward from the electrodes and covering a part of the light-transmitting surface of the individual element (strain layer due to curing shrinkage of the adhesive). Prevent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an optical shutter array element applied to the field of optoelectronics such as a write head of an optical printer.

[0002]

2. Description of the Related Art A PLZT type transparent electro-optic ceramic exhibits optical anisotropy (electro-optic Kerr effect) when an electric field is applied from the outside, and has a property that a polarization plane is rotated according to the electric field strength. Therefore, the PLZ is provided between the polarizer and the analyzer combined in the orthogonal Nicols state by utilizing the above property.
An optical shutter element in which an element made of T is interposed, and an electric field is externally applied to the element to control transmission and blocking of light, and light formed by arranging the optical shutter elements in an array. Shutter array elements are known. Further, this optical shutter element has a very high response speed, and in particular, the optical shutter array element is expected to be applied to a new field such as a writing head of an optical printer.

On the other hand, as such an optical shutter array element, strip-shaped individual elements made of transparent electro-optical ceramics arranged in an array at regular pitches are formed, and film electrodes are formed on both surfaces other than the light transmitting surface. Further, a structure in which an insulating substrate is superposed on the outside in a sandwich shape has been already proposed by the same applicant as Japanese Patent Application No. 4-119331.

FIG. 3 shows an assembly structure of the optical shutter array element proposed above. In the central portion of the element assembly 1, individual elements 6 made of PLZT ceramics are arrayed at a constant pitch. Are arranged in a shape, and each individual element 6
A film-shaped common electrode 2 and a voltage application electrode 3 are formed on both side surfaces of the. Further, the individual elements 6 arranged in an array are sandwiched and sandwiched between the electrodes 2, 3 on the left and right sides thereof.
Insulating substrate (made of quartz plate or heat-resistant tempered glass) 7 is laminated with epoxy adhesive 8
Further, the lead-out leads 9 and 10 are formed in a pattern on the upper surface of the insulating substrate 7 by connecting one end to each of the electrodes 2 and 3. It should be noted that the gap between the individual elements 6 arranged in a line is filled with an adhesive 8 to close it, and the polarizer 4 and the analyzer 5 should be combined in the orthogonal Nicols state with the assembly sandwiched therebetween. The optical shutter is composed of.

When a voltage is selectively applied from the outside between the leads 9 and 10 to the optical shutter array element having such a configuration, the PLZT individual element 6 has a uniform parallel inside as shown by an arrow E. An electric field is created. As a result, the polarization state of the light passing through the individual element 6 via the polarizer 4 changes due to the electro-optical effect that appears in the individual element, and the element operates as an optical shutter. That is, since the polarization state of the light beam passing through the individual element 6 is unchanged when no voltage is applied to the individual element 6, the input light is shielded by the crossed Nicols polarizer 4 and analyzer 5. On the other hand, when a voltage is selectively applied to the individual element 6, the light beam is changed into elliptically polarized light due to birefringence when passing through the individual element 6 to which the voltage is applied, and the light is transmitted through the analyzer 5 to be linearly polarized light. Light is output.

[0006]

By the way, it has been found that the optical shutter array element configured as described above has the following problems in terms of characteristics. That is, PL
When the insulating substrate 7 is superposed on the individual element 6 made of ZT ceramic and bonded with the epoxy adhesive 8, contraction occurs in the process of curing the adhesive 8, and the individual element 6 is stressed due to the contraction. It acts to generate a strained layer along the surface that contacts the adhesive.

Moreover, when a strain layer is formed in the individual element 6 of the transparent electro-optical ceramic, the individual element exhibits optical anisotropy due to the photoelastic effect and a birefringence phenomenon appears even in a state in which no voltage is applied, resulting in polarization The state changes. As a result, the individual element partially leaks light even when no voltage is applied, and the contrast ratio is lowered. The present invention has been made for the purpose of solving the above problems, and for the optical shutter array element having the above-described configuration, prevents light leakage of individual elements caused by curing shrinkage of the adhesive. An object of the present invention is to provide an assembly structure of an optical shutter array element with an improved contrast ratio.

[0008]

According to the present invention, the above object is to provide individual elements made of transparent electro-optical ceramics arranged in an array at a constant pitch, and film electrodes formed on both side surfaces of each individual element. It consists of an insulating substrate which is sandwiched between individual elements arranged in an array and is bonded to the electrode surface with an adhesive, and a lead lead which is formed by patterning on the insulating substrate by connecting one end to the electrode of each individual element. In the optical shutter array element, this is achieved by providing a partial light shielding layer on the light transmitting surface of each element along the joint surface with the insulating substrate.

Here, as a concrete means for forming the light-shielding layer in the above-mentioned structure, the lead-out lead patterned on the insulating substrate is extended from the electrode so as to further cover a part of the light transmitting surface of the individual element. Can form a light shielding layer. The extension width of the lead wire is 50 μm.
The following should be set.

[0010]

According to the above construction, the light-shielding layer covers the strained layer appearing on both sides of the light-transmitting surface of the individual element (on the side of the bonding surface with the insulating substrate) due to curing shrinkage of the adhesive. So
Unnecessary light leakage is almost eliminated and the contrast ratio of the optical shutter element is improved.

In this case, when the individual element and the insulating substrate are joined together with an adhesive, the individual elements (about 0.2 mm in plate thickness) are inserted along the joint surface due to the curing shrinkage of the adhesive. The depth of the strained layer that appears varies depending on the type of adhesive, but is about 50 μm or less in most cases. Therefore, the lead-out lead (non-translucent metal film) patterned on the insulating substrate is extended further inward than the electrode to extend and cover a part of the light transmitting surface (distortion layer generation region) of the individual element. If formed in this manner, the protruding portion of the lead lead functions as a light shielding layer,
It is possible to prevent light leakage caused by the photoelastic effect due to the strained layer.

[0012]

Embodiments of the present invention will be described below with reference to FIGS. In the figure, the same members corresponding to those in FIG. 3 are designated by the same reference numerals. That is, in FIG. 1 and FIG. 2, as in the structure of FIG. The lead-out leads 9 and 10 made of a metal film are formed in a pattern on the upper surface of the insulating substrate 7 connected to the electrodes 2 and 3. And
The inner ends of the lead-out leads 9 and 10 are the electrodes 2 and 3 described above.
Extends further inward beyond the individual element 6 (plate thickness of about 0.2
mm) covering a part of the upper surface (light transmitting surface) of the light shielding layer 9
a, 10a is patterned.

Here, the extension width W of the extension leads 9 and 10 corresponding to the light shielding layers 9a and 10a is about 50 μm.
(Corresponding to the depth of the strained layer appearing along the bonding surface of the individual element 6 due to the curing shrinkage of the adhesive 8), and the lead protruding portion is almost the entire area in the longitudinal direction of the individual element 6. Cover it. With this structure, as shown in FIG. 2, the light-shielding layers 9a and 10a formed by extending the lead-out leads 9 and 10 inward appear on both sides of the individual element 6 (on the side of the joint surface with the insulating substrate 7). Since the input light incident on the region of the strained layer is blocked, unnecessary light leakage generated in the individual element 6 due to the photoelastic effect due to the curing shrinkage of the adhesive 8 is prevented.

[0014]

As described above, according to the structure of the present invention, the individual elements made of electro-optical ceramics arranged in an array are provided along the joint surfaces with the insulating substrates arranged on both sides thereof. The light-shielding layer covers the area of the strain layer (due to the curing shrinkage of the adhesive) that appears inside the individual element to block light, so that unnecessary light leakage is almost eliminated, and the contrast ratio of the optical shutter array element is greatly reduced. Improve to.

Further, by forming the light-shielding layer against the light leakage at the same time by extending the lead-out lead formed in a pattern on the insulating substrate to the inner side, it is advantageous to save the labor of forming the light-shielding layer in a separate step. .

[Brief description of drawings]

FIG. 1 is a perspective view of an assembled structure of an optical shutter array element according to an embodiment of the present invention.

2 is a cross-sectional view of the individual element portion in FIG.

FIG. 3 is a perspective view of an assembly structure of a conventional optical shutter array element.

[Explanation of symbols]

 1 Element assembly 2 Common electrode 3 Voltage application electrode 4 Polarizer 5 Analyzer 6 Individual element of PLZT 7 Insulating substrate 8 Adhesive 9 Extraction lead 10 Extraction lead 9a Light-shielding layer 10a Light-shielding layer W Extension width of extraction lead

Claims (3)

[Claims] 1. An individual electrode made of transparent electro-optical ceramics arranged in an array at a constant pitch, film-like electrodes formed on both side surfaces of each individual element, and the electrodes sandwiching the individual elements arranged in an array. In an optical shutter array element comprising an insulating substrate which is superposed on a surface and bonded by an adhesive, and a lead lead which is formed by patterning on the insulating substrate by connecting one end to an electrode of each individual element, a bonding surface with the insulating substrate An optical shutter array element, characterized in that a light-shielding layer is partially provided on the light-transmitting surface of each element along the line. 2. The optical shutter array element according to claim 1, wherein the lead-out lead patterned on the insulating substrate is provided.
An optical shutter array element, characterized in that a light-shielding layer is formed by projecting and extending from the electrode so as to partially cover the light-transmitting surface of the individual element. 3. The optical shutter array element according to claim 2, wherein the extension width of the extraction lead is set to 50 μm or less.