JP2636275B2 - Optical shutter manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical shutter manufacturing method for manufacturing an optical shutter using a plate-like body made of a material having an electro-optical effect such as PLZT. is there.

[Prior art and its problems] Conventionally, as a method of manufacturing an optical shutter using a plate-like body made of a material having an electro-optic effect such as PLZT,
As shown in JP-A-61-38927, a photoresist is applied to the surface of a plate-like body having an electro-optical effect, exposed and developed, and then a groove is cut in the photoresist. After depositing the metal thin film, removing part of the metal thin film deposited by lift-off, opening the shutter and separating the metal thin film on the surface of the plate-like body, removing part of the metal thin film in the groove with a laser or the like A method for providing independent electrodes is known.

However, it is very troublesome to form a pattern using a photoresist on the surface of the plate-like body having the electro-optical effect, or to remove a part of the metal thin film in the groove with a laser or the like, In addition to the time required for the production, equipment for performing such processing in addition to equipment for cutting grooves on the surface of the plate-shaped body is required, and thus there is a problem that the cost required for the equipment is increased.

Also, in order to strongly adhere the metal thin film for the electrode to the surface of the plate-shaped body so as not to peel off, the surface of the plate-shaped body is cleaned by reverse sputtering, and then the metal thin film for the electrode is formed on the surface by a sputtering method. Is known to be effective.

However, when these treatments are performed on the surface of the plate-like body provided with the photoresist as described above, the photoresist is deteriorated and the metal thin film portion for the electrode is contaminated, and the metal thin film for the electrode is attached. There are problems such as reduced strength,
In addition, this contaminant intervenes between the shutter and the electrode,
There have been various problems such as adverse effects when applying a voltage from the electrode to the shutter.

In addition, the deterioration of the photoresist makes it difficult to remove the photoresist by etching, and also causes a problem that the opening of the shutter cannot be performed well.

[Object of the Invention] The present invention has been made in order to solve the above-mentioned problems, and the manufacturing of the optical shutter is simple, the cost required for the equipment is reduced, and the optical shutter is made of a material having an electro-optical effect. In the case where the metal thin film for the electrode is attached to the surface of the plate-shaped body by using the reverse sputtering or the sputtering method, there is no problem such as contamination by the resist film, and the metal thin film for the electrode is formed on the plate-shaped metal body. It is an object of the present invention to provide a method for manufacturing an optical shutter that can be firmly attached to a body surface.

[Means for Solving the Problems] In the method for manufacturing an optical shutter according to the present invention, at least one surface of a plate made of a material having an electro-optic effect has heat resistance different from that of an electrode material in etching characteristics. After forming the resist film, while forming a groove for the electrode by mechanical cutting, the surface of the portion except the shutter region is mechanically cut to remove the resist film in the portion except the shutter region, A metal film for an electrode is formed thereon, and the resist film is removed from the shutter portion by etching to open the shutter portion.

Here, as the heat-resistant resist film having an etching characteristic different from that of the electrode material, a synthetic resin film such as a polyimide resin can be used in addition to a metal film such as chromium or molybdenum or an inorganic dielectric film.

The point is that the resist film does not deteriorate due to the thermal action or the like during reverse sputtering or sputtering. Also, when the resist film is removed from the shutter portion by etching, the electrode material provided on other portions is used. However, it is only necessary that this is not removed together with the resist film.

[Operation] As described above, in manufacturing an optical shutter using a plate made of a material having an electro-optic effect, a heat-resistant resist film having an etching characteristic different from that of an electrode material is applied to at least one surface of the plate. When provided so as to cover the shutter area, the resist film is not deteriorated when the metal film for the electrode is provided by reverse sputtering or sputtering, and the metal film portion for the electrode is contaminated. There is no.

In the case of manufacturing an optical shutter as in the present invention, in addition to the step of cutting a groove for an electrode as in the prior art, an operation of forming a pattern by exposing and developing a photoresist is performed. There is no necessity, the operation of forming a resist film only on the shutter portion can be easily performed, the manufacture of the optical shutter can be easily performed, and no equipment such as photolithography is required.

Embodiment An embodiment of the present invention will be specifically described below with reference to the accompanying drawings.

First, in this embodiment, as shown in FIG. 1 (a), as a plate-shaped body (1) made of a material having an electro-optic effect, a long flat plate whose front and rear surfaces are optically polished in advance. PLZT (1) was prepared. Note that, as in this embodiment, the PL
When ZT (1) is used, an optical shutter that can be driven at a low voltage can be obtained. Specifically, the PLZT (1) has a composition of 9/65/35, a length of 100 mm, a width of 5.0 mm, and a thickness of 0.5.
mm.

Then, as shown in FIGS. 1 (b) and 2, the chromium film (2) having a thickness of about 2000 ° which becomes a resist film (2) is formed on the entire surface of one side of the PLZT (1) by sputtering.
Was formed. The chromium film (2) is a stable film having heat resistance, and has an etching characteristic different from that of an aluminum film (7) for an electrode described later. Removed from 12).
In this case, the aluminum film (7) for the electrode formed on the chromium film (2) is also removed.

Hereinafter, for convenience of explanation, as shown in FIG.
The longitudinal direction of ZT (1) is the X axis, and the width direction, that is, the direction orthogonal to the X axis is the Y axis.

Then, the PLZT on which the chromium film (2) is formed as described above.
The center of (1) was precision cut along the entire length of the PLZT (1) in the X-axis direction to form a common electrode groove (3) as shown in FIG. This cutting was performed with a dicing saw, and a diamond cutter having a blade thickness of 40 μm was used as the cutter. The groove (3) has a groove width of 104 μm, PLZT
A groove having a groove depth a from the surface of (1) of 160 μm was formed.

Further, at a fixed distance from both side edges of the groove (3), precision cutting is performed on both sides of the groove (3) in parallel with the groove (3), that is, in the X-axis direction over the entire length of the PLZT (1). As shown in (1), grooves (4) and (5) for individual electrodes were formed. The grooves (4) and (5) have the same shape, a groove width of 80 μm, a groove depth b of 120 μm, and a depth smaller than the groove depth a of the common electrode groove (3). The interval between the groove (4) and the groove (5) with respect to the groove (3), that is, the width of the convex portions serving as the shutter portions (11) and (12) was 60 μm.
The widths of the shutter portions (11) and (12) and the depths a and b of the grooves (3) and (4) and (5) are determined according to the performance required for the optical shutter array, and It can be arbitrarily selected within the range of the precision of the precision cutting.
However, it is assumed that a> b.

Next, the outside of the groove (4) and the groove (5) was cut continuously from these grooves (4) and (5) to an end to a depth d of 80 μm, and as shown in FIG. Shutter section (11), (1
The chromium film (2) other than 2) was removed. The diamond cutter used here may be the same as that used in the previous cutting, or may be a thick cutter. For example, when the same cutter is used, a single cutting width is about 50 μm. Therefore, the cutting is performed with the feed pitch in the Y-axis direction of the cutter being about 30 μm smaller than the cutting width. . Thus, the shutter unit (11),
When the chromium film (2) other than (12) is removed, the region from which the chromium film (2) has been removed is roughened by cutting.

Next, the PLZT (1) after the above processing is sufficiently washed, and then an aluminum film (7) is formed as a metal film (7) for an electrode on the entire processing surface of the PLZT (1). . Here, in forming the aluminum film (7), in order to improve the adhesive strength, cleaning treatment and sputtering by reverse sputtering are performed under the conditions shown in Table 1 below to process the PLZT (1). An aluminum film (7) having a thickness of about 4 μm was formed on the entire surface.

Even when the aluminum film (7) is formed in this manner, there is no change in the chromium film (2) remaining in the shutter portions (11) and (12), and the contamination of the aluminum film (7) is prevented. Was not seen. In the portion where the surface is roughened by removing the chromium film (2), the contact area with the aluminum film (7) is increased, and the aluminum film (7) is engaged with the unevenness of the surface and is strongly bonded. It became so.

Next, PLZT (1) provided with this aluminum film (7)
Then, cutting was performed again using a dicing saw to determine the shapes of the shutter portions (11) and (12).
In this cutting, the tip angle θ as shown in FIG.
A diamond cutter of 60 mm and a blade thickness D of 200 mm was used. Then, the triangular grooves (6) were sequentially cut at a required groove pitch by the cutter at an angle of 64 ° with respect to the X-axis direction. Here, the groove pitch is about 144 μm, and the groove width and the groove depth e of the groove (6) are determined by a monitor attached to the dicing saw, ie, the groove width at the upper edge of the groove (6), that is, at the surface edge. Was set to be 72 μm, and the groove depth e was about 60 μm, which was shallower than the cutting depth d when removing the chromium film (2). When the groove (6) is cut in this way,
As shown in FIG. 4 (a), the shutter sections (11) and (12)
The groove (6) is cut in the shutter, and each shutter part (11), (12)
However, in the electrode portion, since the groove depth e of the groove (6) is smaller than the cutting depth d when the chromium film (2) is removed as described above, the groove is not cut, and the electrode is not cut. The aluminum film (7) is continuously separated without being separated.

Using a diamond cutter with a blade thickness of 15 μm, a groove (6 ′) having a groove width of about 20 μm and a groove depth c of 140 μm is formed at the center of the groove (6).
1) and (12) are deeply separated, and the surface of the PLZT (1) and the aluminum film (7) in the grooves (4) and (5) are cut at the positions of the grooves (6 '), and the shutter element (11) is cut. ), (12), the individual electrodes (14), (15) and the electrode leads (14l), (15l) were separated.

Here, when the relationship of the cutting depth in each cutting is arranged, as shown in FIG. 6, the condition of a>b>c>d> e is satisfied.

Thus, the groove depth c (= 140 μm) of the groove (6 ′)
Is made shallower than the groove depth a (= 160 μm) of the groove (3), and is made deeper than the groove depth b (= 120 μm) of the grooves (4) and (5). , PLZT (1) surface and aluminum film (7) in grooves (4), (5)
Is cut at the groove (6 '), and the shutter portions (11) and (12), the individual electrodes (14) and (15) and the electrode lead portions (14l) and (15l) are separately formed. The aluminum film (7) on the bottom of the groove (3) serving as the common electrode (13) remains in a continuous state without being cut. That is,
By cutting the groove (6 '), the individual electrodes (14), (15) which are parallel to the three-dimensional shutter portions (11), (12) at the same time.
Can also be made. Therefore, JP-A-61-38
No need for a complicated process such as forming a pattern using a photoresist or removing a part of a metal thin film in a groove with a laser or the like to provide an independent electrode as in the publication of Japanese Patent No. 927, and Can be greatly simplified.

Although the aluminum film (7) at the cut portion is cut off by cutting the groove (6 '), the aluminum film (7) around the cut portion is strongly adhered to the PLZT (1), and thus peels off with the cutting. I never did.

Further, the groove depth e of the groove (6) is made shallower than the cutting depth d when the chromium film (2) is removed, and in the cutting of the groove (6), the aluminum film (7) on the surface of the PUZT (1) is cut. ) Are not cut and are separated by the groove (6 '), so that the electrode lead portions (14l) and (15l) are formed widely, so that connection with an external drive circuit can be easily performed. .

At the end of the manufacturing process, each shutter unit (1
1), (12) The chromium film (2) formed on the window on the upper surface is chemically etched using a solution containing ceric ammonium nitrate and perchloric acid, and this kerom film (2) At the same time, the aluminum film (7) formed thereon was peeled off, and windows on the upper surfaces of the shutter portions (11) and (12) were opened. At this time, the aluminum film (7) adhered to other portions was not peeled off.

As described above, as shown in FIG. 4 (b), an optical shutter array having two rows of shutter arrays (11A) and (12A) in which a plurality of shutter sections (11) and (12) are arranged. 1
0).

In the optical shutter array (10) manufactured in this way, although the shutter portions (11) and (12) are formed by cutting, leakage light due to processing distortion is generated in these edge portions. Very little and very high optical contrast can be obtained. this is,
Since the upper edges of the shutters (11) and (12) are chamfered by the grooves (6), the light incident on the edges of the shutters (11) and (12) is cut off as shown in FIG. It is considered that this is because the light is reflected at the point where the light is applied.

Next, FIG. 8 shows an example in which the optical shutter array (10) is used by connecting it to an external circuit. In the figure, reference numeral (20) denotes a drive circuit (including a semiconductor chip-shaped circuit) for driving each shutter section (11) of the shutter array (11A) by applying a drive pulse, and (21) denotes each of the shutter arrays (12A). A drive circuit for driving the shutter section (12). Drive circuit (20)
Are connected to the individual electrode leads (14l) of the odd-numbered shutter section (11) in the shutter array (11A), while the drive circuit (21) is connected to the shutter array (12A)
Are connected to the individual electrode leads (15l) of the even-numbered shutter section (12).

The drive circuits (20) and (21) are operated in a time-division manner, and as shown in FIGS. 9 (a) and 9 (b), the shutter action of two rows of shutter arrays (11A) and (12A) based on image information. Thus, an image of one line is formed. The time difference is synchronized with the rotation speed of the image forming unit, for example, the photosensitive drum. By driving in this manner, this optical shutter array (10) can achieve a high resolution of 80 μm pitch, that is, 12.5 dots / mm.

In this embodiment, an example in which a chromium film is used as the resist film has been described. However, the resist film is not limited to such a film, and molybdenum, a polyimide resin, or the like can be used. In the case of a resist film using molybdenum, chemical etching should be performed using an aqueous solution containing phosphoric acid and nitric acid, and in the case of a resist film using a polyimide resin, chemical etching should be performed using a hydrazone-based solution. As a result, the aluminum film (7) as the electrode material is not peeled off, and only these resist films are removed.

When forming a resist film made of a polyimide resin, baking is usually performed at about 350 ° C.
PLZT constituting the optical sitter did not change due to such heating.

[Effects of the Invention] As described in detail above, in the method of manufacturing an optical shutter according to the present invention, similarly to the case of forming a groove for an electrode, the surface of a portion excluding a shutter portion region is mechanically cut. Since the resist film is removed by a conventional method, there is no need to perform operations such as forming a pattern by exposing and developing a photoresist in addition to a step of cutting a groove for an electrode as in the related art. Only the operation of forming a resist film can be easily performed, and there is no need to provide facilities such as photolithography, so that an optical shutter can be easily manufactured and the cost required for the facilities can be reduced.

Further, in the present invention, since the heat-resistant resist film is provided on the surface of the plate-like body, when the metal film for the electrode is provided by reverse sputtering or sputtering, the resist film is deteriorated and the electrode film is deteriorated. No contamination occurs in the metal film portion of the substrate, and a metal film for the electrode having high adhesion strength is formed, and contaminants enter between the shutter and the electrode, and a voltage is applied from the electrode to the shutter. Thus, an optical shutter capable of performing stable driving without adversely affecting the operation is obtained.

Furthermore, the opening of the shutter portion can be successfully performed by the etching without the resist film being deteriorated when the metal film for the electrode is provided and the removal of the resist film by the etching becomes difficult.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b), FIGS. 2 and 3, and FIGS. 4 (a) and 4 (b) are explanatory views of a manufacturing process of an optical shutter array according to an embodiment of the present invention. Fig. 2 is Fig. 1 (b)
5 is a partially enlarged sectional view taken along line II of FIG. 5, FIG. 5 is a sectional view of the diamond cutter used in the embodiment, and FIG.
FIG. 7 (a) is a sectional view taken along the line II-II of FIG.
(B) is a plan view and a front view of the shutter element of the embodiment, FIG. 8 is a connection diagram between the optical shutter array and the drive circuit of the embodiment, and FIGS. 9 (a) and (b) are the embodiment. FIG. 10 is a sectional view taken along line III-III of FIG. 4 (b). (1) ... a plate-like body (PLZT) having an electro-optic effect,
(2) ... resist film (chromium film), (3) ... groove for common electrode, (4), (5) ... groove for individual electrode, (7)
...... Metal film (aluminum film) for electrodes, (11), (1
2) Shutter section.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kane Matsubara 2--30 Azuchicho, Higashi-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Camera Co., Ltd. (72) Tomohiko Masuda 2--30 Azuchicho, Higashi-ku, Osaka, Osaka Address: Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Hirohisa Kitano 2-30 Azuchicho, Higashi-ku, Osaka City, Osaka Prefecture Osaka International Building Minolta Camera Co., Ltd. (56) References JP-A-61-38927 (JP, A) JP-A-51-39062 (JP, A) JP-T-62-502783 (JP, A)

Claims (1)

(57) [Claims] An electrode groove is formed by mechanical cutting after forming a heat-resistant resist film having an etching characteristic different from that of an electrode material on at least one surface of a plate made of a material having an electro-optical effect. At the same time, the surface of the portion excluding the shutter portion region is mechanically cut to remove the resist film in the portion excluding the shutter portion region, a metal film for an electrode is formed thereon, and the resist film is etched. And removing the shutter from the shutter to open the shutter.