JPH0731316B2 - Optical shutter array - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical shutter array in which a plurality of shutter elements are one-dimensionally arranged and formed using a substance having an electro-optical effect.

Conventional Technology Conventionally, this type of optical shutter array has a large Kerr constant.
It was configured by using PLZT and forming an electrode pattern on the surface of the wafer (planar electrode type). But,
Due to the drawbacks such as the presence of stray capacitance that causes crosstalk and the high driving voltage, recently, a so-called parallel electric field type structure in which a shutter element is made into a three-dimensional body and an electrode is provided on the opposite surface is disclosed in It is proposed in JP-A-60-159722 and JP-A-60-170828.

In the technology of JP-A-60-159722, a rod-shaped PLZT having a counter electrode formed thereon is bonded onto a glass substrate on which electrodes for connection are patterned in advance, and this is cut at a constant pitch with a diamond cutter. This is an optical shutter array. Another technique disclosed in JP-A-60-170828 uses a photolithography technique, in which a flat PLZT is chemically etched to form a groove in an electrode arrangement portion,
Next, a metal for electrodes is vapor-deposited on the entire surface, and thereafter, an optical shutter array is formed through an etching process by a photolithography technique again so as to have a predetermined electrode pattern and structure.

Problems to be Solved by the Invention However, the former technique has a problem of undergoing an extremely complicated manufacturing process, while the latter technique also has a complicated manufacturing process and is a groove formation by chemical etching. Therefore, the depth of this groove cannot be increased (about 2 μm in the embodiment).
m), there is a problem that it is difficult to reduce the voltage from the viewpoint of driving the shutter.

Further, in order to obtain a desired shutter effect in shutter driving, it is necessary to make the electric field applied to the three-dimensional shutter element uniform, but in consideration of the manufacturing process,
The problem is how to structure the electrode (three-dimensional electrode) that forms the electric field.

An object of the present invention is to provide an optical shutter array that can be driven at a low voltage, is easy to manufacture, and has a desirable shutter effect.

Means for Solving the Problems The optical shutter array of the present invention is a long plate-shaped body having an electro-optical effect, provided along the longitudinal direction thereof, and having electrode thin films intermittently provided on the bottom surface and side surfaces. A first groove, a second groove provided on the bottom surface of the first groove in parallel with the first groove, and having an electrode thin film continuously on the bottom surface and the side surface, and a predetermined distance from the first groove A third groove provided in parallel with the first groove and having an electrode thin film intermittently on the bottom surface and the side surface, and a fourth groove provided at a predetermined pitch over the width of the plate-like body. And a convex portion surrounded by the first, third, and fourth grooves forms a shutter element, and the following condition is satisfied.

d ₁ + d ₂ > d ₄ > d ₃ d ₁ = d ₃ However, d ₁ , d ₂ , d ₃ and d ₄ are the depths of the first, second, third and fourth grooves, respectively.

Action By setting the depths of the first, second, third, and fourth grooves to be d ₁ + d ₂ > d ₄ > d ₃ , it is provided in the second groove when the fourth groove is formed. The electrode thin film provided in the third groove can be connected to each shutter element through the electrode thin film of the first groove, while the electrode thin film provided in the third groove can be intermittently provided for each shutter element. Greatly simplified.

Further, by setting the depths of the first and third grooves to be d ₁ = d ₃ ,
The lengths of the electrodes sandwiching the shutter element in the depth direction can be made equal, and an electric field that is uniformly parallel to the shutter element can be formed.

Embodiment Hereinafter, the present invention will be specifically described with reference to an embodiment shown in the accompanying drawings.

FIG. 5 is a partial plan view of the optical shutter array according to the embodiment. The optical shutter array (10) made of PLZT is provided with parallel two rows of shutter arrays (11A) and (12A) in the central portion. The shutter array (11A) includes a shutter element (11) having a rectangular window shape.
A) comprises a shutter element (12) having the same shape as the window shape of the shutter element (11). (13) is a common electrode common to the shutter elements (11) and (12) in each column, (1
4) is the individual electrode of each shutter element (11), (15)
Is an individual electrode of each shutter element (12), and each of the individual electrodes (14) and (15) is an electrode lead portion (14l), (15) extending to a side edge of the main body for connecting with a drive circuit.
l).

The common electrode (13) is provided in the groove (3-1) and the groove (3-2) provided on the bottom surface of the groove (3-1). The individual electrodes (14) and (15) are provided on the side walls of the grooves (4) and (5), respectively. The shutter elements, individual electrodes and electrode lead portions of the shutter arrays (11A) and (12A) are parallel to each other at a constant pitch perpendicular to the grooves (3-1), (3-2), (4) and (5), respectively. Separated from each other by a groove (6). The common electrode grooves (3-1) and (3-2), the individual electrode grooves (4) and (5), and the multiple element separation grooves (6) are all formed by precision cutting. ing. A manufacturing process of the optical shutter array (10) will be described with reference to FIGS. 1 to 5 and 7.

As shown in FIG. 1 (a), a long flat plate-shaped PLZT (1) is prepared. Both front and back sides of PLZT (1) are optically polished in advance. Specifically, PLZT (1) has a composition of 9/65/35 and a shape of 100 mm in length, 5.0 mm in width, and 0.5 mm in thickness.

As shown in FIG. 1 (b), a resist pattern (2) is formed in a strip shape at the substantially central portion of the surface of this PLZT (1). The width of the resist pattern (2) was 300 μm, and a general photolithography technique was generally used. This resist pattern (2) is used for removing the deposited film by the lift-off method, as will be described later. The longitudinal direction of PLZT (1) is the X-axis, and the width direction, that is, the direction orthogonal to the X-axis is Y
A sectional view taken along the line II-II is shown in FIG. The thickness of the resist pattern (2) is about 1 μm.

Next, PLZT (1) on which this resist pattern (2) was formed
PLZT the center of the resist pattern (2) of the
Precision cutting is performed over the entire length of (1) to form a common electrode groove (3-1) shown in FIG. And further groove (3
Groove (3-1) from the bottom surface of -1) in the thickness direction of PLZT (1)
Forming a groove (3-2) for the common electrode parallel to. The cutting process was performed with a dicing saw with a high feed rate, and the cutter used was a diamond cutter with a blade thickness of 25 μm. Groove (3
The shape of -1) has a width of 100 μm and a depth d ₁ = 120 μm from the surface of PLZT (1). The groove (3-2) has a width of 50μ.
The depth d ₂ from the bottom surface of the groove (3-1) is m ₂ = 130 μm.

Next, in the same manner as the above grooving step, a certain distance is set from both side edges of the first groove (3-1) for the common electrode, and this groove (3
-1) (in the X-axis direction) is cut over the entire length of PLZT (1) to form grooves (4) and grooves (5) for individual electrodes shown in FIG. The grooves (4) and (5) have the same shape, and the width is 80 μm and the depth d ₃ is 120 μm. The distance between the groove (3-1) and the grooves (4) and (5), that is, the width of the convex portion serving as the shutter was set to 60 μm. The width of the convex portion of the shutter and the depths d ₁ and d ₃ of the grooves (3-1) and the grooves (4) and (5) are
It can be arbitrarily selected according to the performance required for the optical shutter array and within the precision of precision cutting. However, to ensure the uniformity of the parallel electric field
The condition is d ₁ = d ₃ .

The next step is to provide a thin film for electrodes. In the example, aluminum was vapor-deposited on the entire surface including the processed surface of the PLZT (1) by a sputtering method to form an aluminum vapor-deposited film (7) of about 2 μm (FIG. 4).

Next, using a dicing saw for the PLZT (1) provided with this aluminum vapor deposition film (7), this time the direction of the arrow 6A (Y-axis) orthogonal to the direction in which the groove (3-1) extends (X-axis direction). Direction), a large number of grooves (6) for element separation are cut at a constant depth and a constant pitch over the width of the PLZT (1). The depth d ₄ of the groove (6) is 230 μm and the pitch is 80 μm
The groove width is 20 μm. The diamond cutter used for cutting is replaced with a blade thickness of 15 μm.

The cutting depth d ₄ of the groove (6) satisfies the relationship of d ₁ + d ₂ > d ₄ > d ₃ as can be seen from the cross section of FIG. 7. That is, when the grooves (6), (6), (6), ... Are cut, the shutter elements in each row, the individual electrodes thereof, and the electrode lead portions are separated from each other, while the second grooves for the common electrode are formed. (3
The aluminum vapor deposition film (7) provided on the bottom surface of -2) is not scraped off. Almost all of the aluminum vapor deposition film (7) on the bottom surface and side wall of the groove (3-2) is continuous without being divided. Then, the aluminum vapor deposition film on the side wall is continuous with the bottom surface of the first groove (3-1) and the aluminum vapor deposition film on the side wall. Therefore, these grooves (3-
The continuous aluminum vapor deposition film (7) of 1) and (3-2) forms a common electrode of the shutter element (11) group and the shutter element (12) group.

In order to make the aluminum vapor-deposited film continuous to form a common electrode, as shown in FIG. 6, even if the groove (3-2) deeper than the groove (3-1) is not formed, as shown in FIG. ) Depth d ₁ to d ₁
It is considered that the relation of> d ₄ > d ₃ should be satisfied. However, in this case, the shutter elements (11 '), (1
One of the counter electrodes of 2 '), that is, the one on the common electrode side becomes longer, and the electric field becomes non-uniform as shown in the figure, which adversely affects the light (L) subjected to the shutter action. According to the present invention, in order to eliminate this adverse effect, the common electrode groove (3
-1) Depth d ₁ is the depth of grooves (4), (5) for individual electrodes
While making the electrode length the same as d ₃ , the second groove deeper than the groove (3-1) is formed so that the aluminum vapor deposition film for the common electrode remains even when the groove (6) is cut. (3-
2) is provided. Cutting the groove (6) is a very simple process, nevertheless the shutter element and its electrodes can be formed simultaneously. In the conventional example, the element and the electrode formation are separate steps, and each step is very complicated. In comparison with this, the method of the present example brings about a great simplification of the manufacturing process of a high-performance optical shutter array.

The final step of the manufacturing process is the shutter element (11), (12)
This is a step of removing the aluminum vapor-deposited film (7) formed on the upper surface window part. Aluminum vapor deposition film (7) is resist (2)
It is formed on the upper surface and is stripped together with the resist (2) by a resist stripping solution (lift-off method).

As described above, the optical shutter array (10) shown in FIGS. 5 and 7 (a) is obtained. Optical shutter array (10)
Is a shutter array (11A) including a shutter element (11) having electrode lead portions (14l) individually extending to the outer edge, and an electrode lead portion (15) extending to the opposite outer edge.
It is composed of two rows of shutter arrays (12A) which are composed of shutter elements (12) each having the above l). Note that, as shown in FIG. 7 (b), an optical shutter array including only one row of the shutter array (11A) may be used. Groove (5)
It is created in the same manner as the above manufacturing process except for the above process.

FIG. 8 shows a connection diagram of the two-row optical shutter array (10) with an external circuit.

In the figure, (20) is a drive circuit (including a semiconductor chip-shaped circuit) for applying a drive pulse to the shutter element (11) group of the shutter array (11A), and (21) is the shutter array (12
It is a drive circuit for driving the shutter element (12) group of A). The drive circuit (20) and the shutter array (11A) are connected to the individual electrode lead parts (14l) of the shutter array (11A) odd-numbered shutter elements (11), while the drive circuit (21) and the shutter array (11A) are connected. 12A) is connected to individual electrode lead portions (15l) of even-numbered shutter elements (12) of the shutter array (12A). Shutter elements that are not connected to the drive circuits (20) and (21) are not used.

The drive circuits (20) and (21) are operated in a time-division manner, and the shutter action (Fig. 9 (a)) of the two rows of shutter arrays (11A) and (12A) based on the image information causes the dot-shaped lines of the image. 1
A book is formed (Fig. 9 (b)). The time difference is adjusted in synchronization with the rotation speed of the image forming unit, for example, the photosensitive drum. As a result, the optical shutter array of the embodiment achieves a high resolution of 80 μm pitch, that is, 12 bits / mm.

As shown in the above embodiment, two rows of shutter arrays are provided in order to avoid the difficulty of connecting the lead wires between the optical shutter array and the drive circuit so that this high resolution can be achieved. That is, the shutter element and (1
As shown in the partially enlarged plan view of the electrode lead portion (15l) connected to the individual electrode in 2), the electrode lead portion (15l) has a pitch of 80 μm and its width is only 60 μm. In the current lead wire bonder, it is difficult to find a wire bonder having a pitch of 80 μm and a connection average diameter of 60 μm or less and sufficient connection strength. Therefore, in order to suit the current state of the wire bonder, every other electrode lead portion (15l), (14l) is connected to the lead wire at a pitch of 160 μm. Therefore, by doing so, it is possible to easily put the robot on the automation line, and the profit of productivity is large.

FIG. 11 is a partial plan view showing another embodiment. The same reference numerals as those in FIG. 5 denote the same or corresponding ones, and a detailed description thereof will be omitted. In this embodiment, the window shapes of the shutter elements (11) and (12) are trapezoidal. A groove (6) for element separation was formed by a groove (6a) and a groove (6b) in a zigzag shape with their starting ends aligned. The groove (6a) has an incision angle (8) with respect to the X-axis direction of, for example, 89 °, and the groove (6b) has an angle (9) of 91 ° at a constant pitch (for example, 160 μm) over the width of the PLZT (1). It is cut with a diamond cutter with a blade thickness of 15 μm. VII
The cross section taken along the line -VII is the same as in Fig. 7 (a).

The trapezoidal window shape of the shutter element is more advantageous than the previous embodiment in two points of connection with an external circuit and image formation. That is, the electrode lead portions (14l) and (15l) of the shutter elements (14) and (15) (both are shown by hatching) to be used are PLZT (1).
At the edge of, the lower base becomes a wide trapezoid, and the length of the lower base is 14
The center-to-center pitch between the lead portions is 0 μm and 160 μm, which makes it possible to secure sufficient easiness of contact with the lead wire and the strength of contact.

The shutter is driven in the same manner as in FIG. 9 (a), as shown in FIG. 12 (a).
The shutter arrays (11A) and (12A) are driven in a time division manner as described above. The dot-shaped line formed by this is shown in the figure (b). However, the dot-shaped line shown by the solid line is an illustration of the instantaneous projected image assuming that the shutter arrays (11A) and (12A) are instantaneously driven. Actually, when the image is projected by the shutter, for example, the photosensitive drum is rotating, and the shutter element (11),
The projected image of (12) draws a locus on this photoconductor drum, and becomes dots (11d) and (12d) of a rectangular shape shown by a broken line which is equivalent to the locus of the lower base of the trapezoid. These adjacent dots (11d) and (12d) overlap each other at adjacent positions, and the inter-dot gap (6g) is based on the physical gap existing between the shutter elements due to the element separation grooves (6a) and (6b). Fill in. Therefore, by forming the window shape of the shutter element into such a trapezoidal shape, it is possible to form a line having a high dot continuity, and it is possible to obtain a high quality image in the case of image formation. Further, as shown in FIG. 9 (b), when forming the inter-element gap by cutting, the gap (6g) becomes relatively large due to the problem of the blade thickness of the cutter, but the window shape is trapezoidal. The presence of the gap can be covered by

However, in the above embodiment, all the grooves formed in the PLZT (1) were formed by cutting, but these grooves are formed by photolithography technology (liquid phase or vapor phase chemical etching) or in combination with precision cutting. You may do it.

EFFECTS OF THE INVENTION As described above, according to the optical shutter array of the present invention, since a uniform electric field is applied, an optically desirable shutter effect can be expected, and the manufacturing process is not complicated.

[Brief description of drawings]

1 (a), (b), FIG. 2, FIG. 3, and FIG. 4 are explanatory views of a manufacturing process of an optical shutter array according to an embodiment of the present invention, and FIG. 5 is a partial plan view of a finished product. Fig. 6 is a sectional view of a background example, Fig. 7 (a) is a sectional view taken along the line VII-VII of Figs. 5 and 11, and Fig. 7 (b) is one row of shutter arrays. FIG. 8 is a connection diagram between the optical shutter array and the drive circuit, FIGS. 9 (a) and 9 (b) are explanatory views of the shutter drive, and FIG. 10 is a partially enlarged view of the electrode lead portion. , FIG. 11 is a partial plan view of another embodiment, and FIGS.
It is explanatory drawing of the shutter drive of the Example of the figure. 1 ... Long-plate PLZT, 3-1,3-2 ... groove for common electrode, 4,5 ... groove for individual electrode, 6,6a, 6b ... groove for element separation, 7 ...... Aluminum vapor deposition film as electrode, 10 ...... Optical shutter array, 11,12 ...... Shutter element, 13 ・ ・ ・
… Common electrodes, 14,15 …… Individual electrodes, 11A, 12A …… Shutter array.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomohiko Masuda 2-30 Azuchi-cho, Higashi-ku, Osaka City, Osaka Prefecture Osaka Osaka Building Minota Camera Co., Ltd. Examiner Kimio Yoshino

Claims (1)

[Claims] 1. A long plate-like body having an electro-optical effect, which is provided along the longitudinal direction thereof and has a first groove having electrode thin films intermittently formed on the bottom surface and side surfaces thereof, and the first groove of the first groove. A second groove provided on the bottom surface in parallel with the first groove and having an electrode thin film continuously on the bottom surface and the side surface, and in parallel with the first groove with a predetermined distance from the first groove. The third groove provided on the bottom surface and the side surface having the electrode thin film intermittently, and the fourth groove provided in large numbers at a predetermined pitch over the width of the plate-like body are provided. An optical shutter array characterized in that the convex portion surrounded by the fourth groove forms a shutter element and satisfies the following conditions. d ₁ + d ₂ > d ₄ > d ₃ d ₁ = d ₃ However, d ₁ , d ₂ , d ₃ and d ₄ are the depths of the first, second, third and fourth grooves, respectively.