JPH0731315B2 - Optical shutter array element - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical shutter that uses a substance having an electro-optical effect, and more particularly to an optical shutter array element that is expected to be used in an optical application device.

Conventional technology Materials with electro-optic effect, especially PLZT with large Kerr constant
A plurality of these optical shutter elements are arranged one-dimensionally to form an optical shutter array element, and a polarizer and an analyzer are combined with this to form an optical shutter. Such an optical shutter has a high response speed and is expected to be applied to a high-speed printer, especially an electrophotographic printer.

Conventionally, this type of optical shutter array element has been used for wafer-shaped PL
Although it was configured by forming an electrode pattern on the surface of ZT (planar electrode type), recently, due to drawbacks such as the presence of stray capacitance and high driving voltage, the shutter element has recently been formed into a rectangular solid shape. A so-called parallel electrode type structure in which electrodes are formed on opposite surfaces has been proposed, for example, in Japanese Patent Laid-Open Nos. 60-159722 and 60-170828.

In the technique of JP-A-60-159722, a rod-shaped PLZT on which a counter electrode is formed is adhered 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. The optical shutter array element is used. Another technique disclosed in Japanese Patent Laid-Open No. 60-170828 uses a photolithography technique, in which flat plate-shaped PLZT is chemically etched to form a groove in an electrode arrangement portion, and then a metal for an electrode is formed on the entire surface. After vapor deposition, the optical shutter array element is completed 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), it is difficult to reduce the voltage from the viewpoint of driving the shutter element.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical shutter array element which facilitates lowering of shutter drive voltage and is extremely easy to manufacture.

The optical shutter array element according to the present invention is provided on a long plate-shaped body having an electro-optical effect along a longitudinal direction thereof, and has a first groove having a metal thin film for electrodes on a bottom surface and a side surface, and A second groove provided along the first groove at a predetermined distance from the first groove and having a metal thin film for electrodes intermittently on the bottom surface and side surfaces; and a predetermined pitch in the width direction of the plate-shaped body. And a plurality of third grooves, and an optical shutter portion composed of a protrusion of a plate-like body surrounded by these first, second and third grooves, and satisfy the following conditions. To do.

a>c> b where a, b, and c are the depths of the first, second, and third grooves, respectively.

By setting the depths of the first, second, and third grooves to be a>c> b, the metal thin film for the electrode provided in the first groove is formed when the third groove is formed. The metal thin film for the electrode provided in the second groove can be intermittently provided for each shutter portion while being shared by each shutter portion. Therefore, the manufacturing process is greatly simplified.

Examples Hereinafter, specific examples will be described with reference to the accompanying drawings.

FIG. 4 shows an optical shutter array element of one embodiment. The optical shutter array element (10) has a rectangular parallelepiped optical shutter section (11), (11), ...
Optical shutter parts (12), (1 having the same shape as the optical shutter part (11)
2) An array of two rows of element arrays (12A) of ...
(13) and (13) are the element array (11A) and the element array (12
A common electrode provided so as to straddle A), (14) is a control electrode of the optical shutter section (11) and is provided with a lead section (14l) for connecting to an external drive circuit.
The control electrode (15) is also provided with a lead portion (15l) for connecting to an external drive circuit.

Grooves (3) provided with common electrodes (13), (13), grooves (4), (5) provided with control electrodes (14), (15) and element arrays (11A), (12A) The numerous grooves (6), (6), ... Which separate the respective elements in common are formed by cutting. A manufacturing process of the optical shutter array element (10) will be described with reference to FIGS.

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. PLZT (1) has a composition of 9/65/35, for example, and its shape is 100 mm in length, 5 mm in width, and 0.5 mm in thickness.

As shown in FIG. 1 (b), a strip-shaped resist pattern (2) is formed on the surface of the PLZT (1) almost at the center. The width of the resist pattern (2) was set to 300 μm, and the general photolithography technique was used. This resist pattern (2) is used for removing the vapor-deposited metal, as described later. In addition, the longitudinal direction of PLZT (1) is X
A cross-sectional view taken along line II-II is shown in FIG. 2 with the direction orthogonal to the X-axis direction in the axial direction and the width direction as the Y-axis direction. The thickness of the resist pattern (2) may be about 1 μm.

Next, PLZT on which this resist pattern (2) was formed
The center of the resist pattern (2) in (1) is cut in the X-axis direction over the entire length of PLZT (1) to form a common electrode groove (3) shown in FIG. Cutting accuracy is 5μ
m, and a diamond cutter with a blade thickness of 25 μm was used. The groove (3) has a width of 80 μm and a depth of a = 150 μm. The depth is based on the surface of PLZT (1).

Further, in a manner similar to the above-mentioned cutting step, cutting is performed at a constant interval from both side edges 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 FIG. 3, the groove (4) and the groove (5) for the array element
Are sequentially formed. Grooves (4) and (5) have the same shape and width
80 μm and depth b = 110 μm. Groove (3) and groove (4),
The interval of (5), that is, the length of the shutter window of the optical shutter unit was 80 μm. The length of the shutter window 80 μm and the depths a, b of the grooves (3), (4) and (5) can be freely adjusted according to the performance required for the optical shutter and within the range of cutting accuracy. Can be selected. However, the condition is a> b.

The next step is to provide a conductive metal for the electrodes.
In the example, the PLZT was cut using the sputtering method.
Aluminum was vapor-deposited on the entire surface including the processed surface of (1).

Next, the PLZT (1) vapor-deposited on the entire aluminum processed surface was cut over the entire length at a constant pitch in the Y-axis direction orthogonal to the X-axis direction using a dicing saw, and as shown in FIG. Many grooves (6) for element isolation, (6), ...
To form. The diamond cutter used had a blade thickness of 15 μm. The width of the groove (6) is 20 μm and the depth c is 130 μm.
m and the pitch was 80 μm. The depth c satisfies the condition of a>c> b. That is, when the depth c of the groove (6) is set in this way with respect to the grooves (3), (4), (5), the grooves (4),
While the control electrode and the electrode lead portion of each shutter element can be separately formed by scraping off a part of the aluminum vapor deposition film of (5),
It is not necessary to scrape off the aluminum vapor deposition film of the groove (3) on the bottom surface portion, and it is possible to form a planar common electrode and simultaneously form a counter electrode having substantially the same shape as the control electrode. Compared to the electrode formation in the conventional example, which took a very complicated process,
In this example, only grooving is required, and the process for forming electrodes is greatly simplified.

Finally, the aluminum vapor deposition film formed on the upper surfaces of the shutter elements (11) and (12) is removed. The aluminum vapor deposition film is formed on the resist (2), and the resist (2) is stripped together with the aluminum vapor deposition film by a resist stripping solution (lift-off method). In addition to the method of using a resist, the method of removing the deposited film does not use a resist (the resist forming step is omitted), and the metal thin film directly deposited on the PLZT surface is scraped off by a method similar to optical polishing. Good.

As described above, the optical shutter array element (10) shown in FIG. 4 is obtained. The optical shutter array element (10) includes an element array (11) including optical shutter sections (11), (11) ,.
A) and the optical shutter section (12), (12) ,. An equivalent circuit diagram is shown in FIG. In the figure, (20) is a drive circuit (including a semiconductor chip-shaped circuit) for applying a drive pulse to the shutter element (11) of the element array (11A), and (21) is an element array (12A).
Is a drive circuit for driving the shutter element (12).

The drive circuit (20) and the element array (11A) are electrically and individually connected to the odd-numbered optical shutter sections (11) of the element array (11A) via lead wires, while the drive circuit (21) is connected. The element array (12A) and the element array (12A) are individually connected via lead wires similarly to the even-numbered optical shutter section (12) of the element array (12A). The optical shutter part that is not connected to the drive circuits (20) and (21) is not used. The drive circuits (20) and (21) are operated in a time division manner, and one dot line of an image is formed by the shutter action of the two rows of shutter arrays (11A) and (12A).
The time difference is adjusted by rotating the image forming unit, for example, the photosensitive drum. As a result, the optical shutter of the embodiment has a thickness of 80 μm.
High resolution of pitch or 12 bits / mm can be achieved.

As shown in the above embodiment, the two shutter rows are provided in order to avoid the difficulty of connecting the lead wires between the optical shutter array element and the drive circuit so that the high resolution can be achieved. That is, as shown in the partially enlarged plan view of the electrode lead portion (15l) connected to the control electrode of the shutter element (12) in FIG. 6, the electrode lead portion (15l) has a pitch of 80 μm and its width is only 60 μm. Absent. In the current lead wire bonder, it is difficult to find a lead wire bonder having an accuracy of a pitch of 80 μm and having a connection average diameter of solder of 60 μm or less and sufficient connection strength.

Therefore, every other electrode lead part (15l), (14l), ie 160
It is designed to be connected to a lead wire at a pitch of 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. 7 shows another embodiment of the two shutter rows.
The optical shutter array element (10) of FIG. 4 is improved from the viewpoint of lead wire connection. That is, the end portions of the electrode lead portions (14l) and (15l) of the optical shutter portions (11 ') and (12') that are not operated are scraped off to remove the deletion portion (34),
(35), when connecting the lead wires to the ends of the electrode lead parts (14l) and (15l) of the optical shutter part to be operated by soldering or the like, the connection points are made by the deletion parts (34) and (35). (An average diameter of 100 μm or more is required to secure the connection strength) effectively prevents the connection with the adjacent electrode lead portion.
The deleted portions (34) and (35) can also be formed by using a diamond cutter as in the groove processing.

Further, in place of such cutting work, in the example shown in FIG. 4, even if the connection point part is connected to the adjacent electrode lead part, the shutter is not operated so that it does not hinder the actual operation of the shutter. The shutter window of the device may be masked in advance.

In each of the above-mentioned embodiments, two rows of shutter rows are provided in consideration of connection with an external drive circuit, but it is not necessary to pay particular attention to this connection, or there is another precision connection technology. Then, basically, Fig. 8 (a), (b)
The shutter row may be one row as shown in FIG. It goes without saying that these embodiments also function similarly to those of the two rows and are equivalent. All the optical shutter sections may be operable, or every other optical shutter section may be operable. The cutting process is not limited to the size and shape of the above-described embodiment, and cutting can be performed within a range that the accuracy of the cutter allows. Further, if the groove is made deeper, the drive voltage can be made lower, and even if the width of the shutter window is made larger, the drive voltage can be lowered.

8 (a) is an example in which the groove (6) is provided up to the groove (3), and FIG. 8 (b) is an example in which the groove (6) is cut to fill the width direction of the PLZT (1). The latter is superior in terms of ease of use, but the former having a large area of the common electrode (13) for providing the base bias is advantageous in electrical characteristics.

In the above example, the lead parts (14l), (15l)
Is for connecting lead wires, and does not need to particularly project from the bottom surfaces of the grooves (4) and (5), and is provided in the same plane as the bottom surfaces of the grooves (4) and (5). You may be asked.

EFFECTS OF THE INVENTION As described above, according to the present invention, there is no crosstalk,
An optical shutter array element that can be driven at a low voltage can be obtained substantially only by grooving, and the manufacturing process can be extremely simplified.

[Brief description of drawings]

1 (a), (b), FIG. 2, FIG. 3, and FIG. 4 are explanatory views of the manufacturing process of the optical shutter array element according to one embodiment of the present invention. FIG. 5 is a diagram schematically showing an example optical shutter array element, FIG. 5 is an equivalent circuit diagram showing connection with a drive circuit, FIG. 6 is a partially enlarged plan view of an electrode lead portion, and FIG. 7 is another embodiment. Showing FIG. 8 (a),
(B) is a diagram showing an embodiment in which there is one shutter row. 1 ... PLZT, 3 ... groove for common electrode, 4,5 ... groove for control electrode, 6 ... groove for element isolation, 11,12 ... optical shutter part, 13 ... common electrode, 14 , 15 …… Control electrode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page Examiner Kimio Yoshino (56) References JP-A-60-159723 (JP, A)

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 a metal thin film for electrodes on a bottom surface and a side surface, and along the first groove. And a second groove having a predetermined distance from the first groove and intermittently having a metal thin film for electrodes on the bottom surface and side surfaces, and a large number of grooves are provided at a predetermined pitch in the width direction of the plate body. An optical shutter array element comprising: a third groove; and an optical shutter portion including a protrusion of a plate-like body surrounded by the first, second and third grooves, and satisfying the following conditions. . a>c> b where a, b, and c are the depths of the first, second, and third grooves.