JPH03206419A - Optical shutter array - Google Patents

Abstract

PURPOSE:To flatten the surface of a substrate after electrode formation, to eliminate the unevenness on an insulating layer, and to prevent stress after adhesion from being irregular by forming individual electrodes of embedded electrodes formed by embedding conductive metal in plural groove parts formed on the substrate surface. CONSTITUTION:The individual electrodes 3 consist of the embedded electrodes formed by embedding the conductive metal in plural groove parts 2A formed in the surface of the substrate 2 composed of an electrooptic effect element. The substrate surface after the electrodes 3 are formed is therefore flattened to prevent the surface of the insulating layer 9 covering the surface from being irregular, and the irregularity in the adhesion is prevented from being generated at the time of the adhesion to the side of a support member 5. Consequently, stress is applied uniformly to the substrate 2 even after the substrate 2 and support member 5 are adhered and sliced at right angles to the lamination direction, and such a problem as a shutter function defect due to the generation of a stress distribution in the substrate 2 is prevented from being generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical shutter array that utilizes electro-optic effects.

[Conventional technology]

It is known that the electro-optic effect is a phenomenon in which the birefringence of a medium changes in response to an applied electric field.Using this phenomenon,
By controlling the applied electric field, light can be transmitted through the medium.
An optical shutter array that performs a light shielding operation is known.

In recent years, there has been a demand for an optical shutter array that is inexpensive and operates reliably with a low operating voltage. Patent application Hei 1-549
In No. 42, a novel optical shutter array having the configuration shown in FIGS. 2(A) and 2(B) was proposed.

To explain in more detail, this optical shutter array
As shown in Figures (A) and (B), two sets of shutter arrays 1, 1 are joined back to back with their common electrodes facing each other to form one block. The shutter array 1 of the set has an electro-optical effect P
A substrate 2 made of a substance such as LZT, a plurality of individual electrodes 3,..., 3 provided on one surface of the substrate 2, and a common electrode 4 provided on the other surface of the substrate 2, a support member 5 that sandwiches the individual electrodes 3, . . . , 3 with the substrate 2;
,...,3 are individually connected to the terminal electrodes 6,...
・, 6. These two sets of shutter arrays 1.1 have an insulating layer 8 which also serves as an adhesive of Sin2 and low-melting glass between each of the common electrodes 4, 4 facing each other and between each individual electrode 3 and the support member 5. ,9 are formed and l
It is consolidated to form two blocks. Also,
Individual electrodes 3, ..., 3 formed on each substrate 2, 2
, and the terminal electrodes 6, . They are arranged in a staggered pattern. Further, one terminal electrode 7 is simultaneously connected to the common electrodes 4, 4, which are bonded via an insulating layer 8, which also serves as an adhesive, such as low melting point glass or Sin.

Note that the electrodes 3 and 4 are made of an electrode material such as aluminum, and are formed into a desired shape and thickness by vacuum evaporation or the like. Further, the common electrode 4 may not be a single electrode covering the entire surface of the substrate 2 as shown in the figure, but may be a plurality of electrodes corresponding to the individual electrodes 3, . . . , 3.

The substrate 2 having an electro-optic effect is a medium exhibiting a phenomenon in which birefringence changes in response to an applied electric field, such as PLZ.
The use of T is preferred. PLZT is (Pb, La) (
It is a ceramic represented by the chemical formula Zr, Ti), and has advantages as a high-speed optical shutter, such as high transmittance, large electro-optic coefficient, fast response speed, and no moving parts.

Further, as the support member 5, ceramics can usually be used, and preferably alumina ceramics or glass is used.

Now, in the optical shutter array configured as described above, if a predetermined voltage is applied between any individual electrodes 3,..., 3 and the common electrode 4 to form an electric field, their The PLZT in between causes birefringence, and if a polarizer and an analyzer are constructed with polarizing plates before and after the PLZT, it operates as a shutter.

For example, in FIG. 2(A), when an electric field is applied between the upper individual electrode 3 and the common electrode 4, the PL between them
The shutter portion A-, of ZT2 operates, allowing light to pass through. In addition, the symbol A −1 y A − z p...,
A and N indicate the shutter section. By the way, as shown in FIG. 3, the method for manufacturing the above-mentioned optical shutter array is as follows: First, an electrode material such as aluminum A1 is fixed on one entire surface of the PLZT substrate 2 by vacuum evaporation. A thin film 10 having a certain thickness is formed [FIG. 3(A)]. and,
Striped individual electrodes 3, . . . , 3 are formed on this Al thin film 10 by photolithography [Fig. 3 CB
)Ko.

Next, an electrode material such as A1 is fixed to the other surface (back side) of the PLZT substrate 2 by vacuum evaporation or the like to form a common electrode 4 on the entire surface [FIG. 3(C)]. In this case, common electrodes may be formed only in the portions corresponding to the individual electrodes by the same method as for the individual electrodes 3, . . . , 3.

Next, a thin film 8 of Si○2 is formed by sputtering or the like so as to cover the electrodes 3, .
9 to form block 11 [Fig. 3 (D)
Ko . After forming the two sets of blocks 11 described above, the two sets of blocks l1 are butted back to back so that the common electrodes 4, 4 face each other, and the individual electrodes 3, . . . on one support member 5 are formed. 3 is the individual electrode 3 on the other support member 5,
. Furthermore, blocks made of ceramics or the like as supporting members 5 are stacked on each of the individual electrodes 3, . . . , 3 through spacers (not shown). After that, the support member 5
A low melting point glass l2 is introduced under heating between the insulating layer 9 on the individual electrode side and the insulating layer 8 on the common electrode side, and the whole is solidified into a block shape [Fig. 3(E)].

Next, this block 13 is sliced to a desired thickness in a plane perpendicular to the stacking direction, that is, in a direction perpendicular to the PLZT substrate 2 [FIG. 3(F)]. After polishing the sliced block chip 14, one side of the block chip 14 is coated with an electrode material such as aluminum in a thin film form by vacuum deposition or the like, and desired terminal electrodes 6, . . . , 6 are formed by photolithography. on the support member 5, and the common electrodes 4, 4 . A terminal electrode 7 is formed on the top [FIG. 3(G)].

Note that the terminal electrodes 6, . . . , 6 correspond to the corresponding individual electrodes 3, .
...3, respectively, and the terminal electrode 7 is connected to both common electrodes 4.
, 4 are connected at the same time.

Now, in the optical shutter array manufactured as described above, an electric field is applied between the individual electrodes and the common electrode, which are formed on a plane parallel to the light transmission direction of the electro-optic effect element, and the electro-optic Since the effect appears uniformly in the thickness direction, silver movement can be achieved with low voltage. In addition, since a material with an electro-optic effect, such as PLZT, is used only in the shutter part, and a support member such as another ceramic is used in the part where the terminal electrodes are wired, the amount of PLZT used is small, resulting in low cost. It is possible to

[Problem to be solved by the invention]

By the way, in the optical shutter array with the above structure,
As explained with reference to FIG. 3, the individual electrodes 3 are laminated on one substrate surface of the PLZT substrate 2, and then the insulation M9 is coated. Then, since the height (thickness) of the portion where the individual electrode 3 is present and the portion where it is not varies, the stress distribution applied to the PLZT substrate 2 becomes worse. In addition, as shown in FIG. 4, the surface of the insulating layer 9 is likely to be uneven, and the height of the part of the insulating layer 9 where the electrode 3 is located and the part where the electrode 3 is not is different. When bonding, the low melting point glass 12 may have uneven thickness or pores, resulting in problems such as uneven bonding or uneven stress in the PLZT substrate 2. Also, when adhering like this, PLZT
When stress unevenness occurs in the substrate 2, birefringence occurs, and light is transmitted through the cross-arranged polarization slopes even when no electric field is applied, impairing its function as an optical shutter.

The present invention has been made in view of the above circumstances, and can flatten the surface of the substrate after electrode formation, eliminate unevenness on the insulating layer, and prevent the occurrence of stress unevenness after bonding. An object of the present invention is to provide a light shutter array with a structure.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a substrate having an electro-optic effect, a plurality of individual electrodes provided on one surface of the substrate, a common electrode provided on the other surface of the substrate, In an optical shutter array comprising a support member sandwiching the individual electrodes between the substrate and terminal electrodes provided on the support member and individually connected to each of the individual electrodes, the individual electrodes are connected to the substrate. It is characterized by comprising a buried electrode formed by burying a conductive metal into a plurality of grooves formed on the substrate surface.

[For production]

In the optical shutter array according to the present invention, the individual electrodes are formed by embedded electrodes formed by embedding conductive metal into the plurality of grooves formed on the substrate surface, so that the substrate surface after electrode formation is flat. This prevents the surface of the insulating layer coated thereon from becoming uneven, and prevents the occurrence of uneven adhesion when adhering to the supporting member side, and the occurrence of stress distribution in the substrate after adhesion. Ru.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

The schematic structure of the optical shutter array according to the present invention is the same as that shown in FIGS. a plurality of individual electrodes 3, a common electrode 4 provided on the other surface of the substrate, and a plurality of individual electrodes 3 between the individual electrodes 3 and the substrate 2.
The terminal electrode 6 is provided with a support member 5 sandwiched between the support members 5 and the terminal electrodes 6 provided on the support member 5 and individually connected to each of the individual electrodes 3. Here, the difference from the above-mentioned optical shutter array is that the individual electrodes 3 are formed by filling conductive metal into a plurality of grooves formed on the substrate surface.

Here, FIG. 1 is a diagram showing the shape and method of individual electrodes in the optical shutter array according to the present invention, and the method of forming the electrodes will be explained below.

First, PLZT with electro-optic effect (9/65/3
5) Prepare a substrate 2 consisting of the following [Fig. 1 (1)].

Next, a striped pattern for embedded electrodes is formed on one surface of the substrate 2 by a photolithography process. To explain more specifically, for example, a positive photoresist (photosensitive agent) 20 is uniformly applied to one surface of the substrate 2, and ultraviolet rays are applied through a photomask so that the light is applied only to areas that do not require electrodes. The photosensitive agent in the exposed area is removed using a developer, and the remaining photosensitive agent 20 forms a striped pattern for the embedded electrode.
Figure 1 (2).

Next, using the remaining photosensitive agent 20 as a protective film, a groove 2A is formed in the substrate 2 by etching techniques (dry etching, wet etching) [see FIG. 1 (3)].

Next, a conductive metal (A1, Au, A
(g, Cu, Ni, Mo, W, etc.) using techniques such as vacuum evaporation, sputtering, and plating [Figure 1 (4)]. Thereafter, the photosensitive agent 20 used as a protective film is removed, and the conductive metal in the groove other than the embedded electrode 3 is removed to form the substrate 2 in which the electrode 3 is embedded [Fig. Ko. That is, when the substrate 2 on which the conductive metal film has been formed as shown in FIG. Only the conductive metal remains on the substrate 2, forming the buried electrode 3.

According to this method, if the depth at the time of groove processing and the film thickness of the conductive metal are not equal, the surface of the substrate 2 made of PLZT or the like will not be flat. Therefore, in such a case, it is better to flatten the substrate surface by lapping or the like.

Now, as shown in FIG. 1(5), an insulating layer 9 is formed on the surface of the substrate 2 on which the individual electrodes 3 consisting of buried electrodes are formed, and a common electrode 9 is formed on the back side of the substrate 2. 4 and insulation N
8 is shaped, and a block equivalent to that shown in FIG. 3(D) is formed [FIG. 1(6). Note that when the common electrode 4 is formed only in the portion corresponding to the individual electrodes, the common electrode 4 side is also formed of a buried electrode in the same manner as the individual electrode 3 side.

Now, after forming the block shown in FIG. 1(6) through the above steps, an optical shutter array is manufactured through the same steps as shown in FIGS. 3(E) to 3(G).

Now, in the optical shutter array according to the present invention manufactured as described above, grooves are formed by etching on the substrate 2 made of electro-optic elements, embedded electrodes are formed in the grooves 2A, and individual electrodes 3 are formed. By doing this, when forming the insulating layer 9 as shown in Figure 1 (6), it is possible to almost eliminate the unevenness on the insulating layer M9, so even if low melting point glass is applied thereon, there will be no unevenness in the thickness. This reduces the occurrence of uneven adhesion when adhering to the supporting member side.

〔Effect of the invention〕

As explained above, in the optical shutter array according to the present invention, individual electrodes are formed by embedded electrodes formed by embedding conductive metal in a plurality of grooves formed in the substrate surface of a substrate made of electro-optic effect elements. This flattens the surface of the substrate after forming the electrode, prevents the surface of the insulating layer coated thereon from becoming uneven, and prevents uneven adhesion when adhering to the support member side. . therefore,
Even after the substrate and the supporting member are bonded together, stress is uniformly applied to the substrate, preventing stress distribution within the substrate, and preventing problems such as shutter malfunction due to stress distribution.

Further, according to the present invention, since the substrate surface is flattened,
It becomes possible to reduce the thickness of the low melting point glass for bonding and to improve workability and reduce manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing an example of the electrode shape and process of the optical shutter array according to the present invention. FIG. 2 is a diagram showing an example of an optical shutter array to which the present invention is applied, in which FIG. 2A is a plan view and FIG. 2B is a sectional view taken along the line ■--■. FIG. 3 is a process diagram showing an example of the manufacturing process of an optical shutter array according to the prior art. FIG. 4 is an explanatory diagram of the drawbacks of the prior art. 1---Shutter array, 2...Substrate having electro-optic effect, 3...Individual electrode, 4...Common 1! cage, 5... support member, 6, 7... terminal electrode. Shape I

Claims (1)

[Claims] A substrate having an electro-optic effect, a plurality of individual electrodes provided on one surface of the substrate, a common electrode provided on the other surface of the substrate, and the individual electrodes are sandwiched between the substrate. In an optical shutter array comprising a support member and terminal electrodes provided on the support member and individually connected to each of the individual electrodes, the individual electrodes are electrically conductive in a plurality of grooves formed on the substrate surface. An optical shutter array characterized by comprising embedded electrodes formed by embedding metal.