JPH0310211A - Optical shutter element - Google Patents

Abstract

PURPOSE:To reduce the quantity of leakage light due to the working strain by providing notched parts on both end parts on the top surface of a projection part and forming a light transmission surface except the notched parts. CONSTITUTION:The notched parts 5 are provided on both end parts on the top surface of the projection part 3 and the light transmission surface 4 is formed except the notched parts 5. Namely, the projection part 3 is formed previously to easy-to-work size and the notched parts having necessary width are provided on both end parts on the top surface of the projection part 3 according to the requested width size W of the light transmission surface. When the distance between adjacent projection parts 3 is limited and the size ratio W/H of the projection parts decreases inevitably to disable the attainment of the purpose only by the effect of the notched parts 5, step parts 7 are formed on both sides of the root part of the projection part 3 to increase the thickness of the projection part substantially, and consequently the working strain which is generated in the vicinity is reduced to reduce the leakage light. Consequently, the leakage light due to the working strain of an optical shutter is reduce.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application This invention relates to the improvement of optical shutter elements that utilize electro-optic effects, and particularly relates to a groove-shaped electrode whose light-transmitting surface is the upper surface of a protrusion formed on a substrate. In this method, notches were provided on both sides of the two sides of the convex part of the optical shutter element, which has a relatively high convex height, to improve manufacturability, and the groove shape was further made step-like to reduce the occurrence of the convex part. The present invention relates to an optical shutter element that reduces the amount of light leakage caused by processing distortion.

BACKGROUND ART An optical shutter using the electro-optic effect has a structure in which (PbLaXZr
Ti) Oa (hereinafter referred to as PLZT), LiNbO3, B112
It is made of a ceramic substrate such as SiO2O, and is constructed by arranging an optical shutter element in which the electric field direction forms a 45° intersection angle with the polarization direction of the large side light. It is used.

For the optical shutter element, as shown in Fig. 3, the required grooves (2) and convexes (3) are formed in parallel on the surface of a substrate (1) having an electro-optical effect using a peripheral blade cutter, etc. (3
) A structure is known in which the upper surface is a light transmitting surface (4) and a groove-shaped electrode is formed by covering the four parts (2) with a required electrode material (6).

In such a groove-type electrode configuration, the electric field is effectively permeated and distributed inside the convex portion (3), so it is possible to reduce the driving voltage, and the configuration is suitable for the recent demands for miniaturization and low driving voltage. It tends to be used frequently.

The optical shutter element shown in FIG. 3, which details the problems of the prior art, has the advantages mentioned above, but today not only is there a need for miniaturization, but also various new shutter functions are required, and The dimensions of the transmission surface and the groove are limited, and the shape tends to be complicated.

In particular, there is a strong tendency for the width of the light transmitting surface to become narrow, and due to the need to reduce the driving voltage, it is undesirable to make the depth of the groove shallow, and the height (H) of the convex portion (3) must be reduced. The ratio (W/H) of the width of the light transmitting surface and the width (W) of the light transmitting surface is small.

Therefore, not only is the machining process extremely complicated during manufacturing, but it is also easily damaged, resulting in poor yields.Furthermore, when machining with a peripheral blade cutter, etc., machining distortion occurs within the convex portion (3), resulting in damage to the convex portion (3). It was confirmed that the underlying light leakage increased.

According to the inventor's experiments, machining distortion occurs in the direction perpendicular to the depth direction of the groove, and increases as the machining depth increases, and in particular, the height (H) of the protrusion (3) It has been found that the aforementioned leakage of light is significant in a structure in which the ratio (W/H) to the width (W) of the surface (4) is 0.5 or less.

Purpose of the Invention The purpose of the invention is to improve the characteristics required of an optical shutter having a structure in which the ratio (W/H) of the width (W) of the light transmitting surface to the height (H) of the convex portion described above is small. In particular, it is an object of the present invention to provide an optical shutter element having a structure that can prevent damage during processing and reduce leakage light caused by processing distortion.

Summary of the Invention 3 - The present invention provides an optical shutter element in which a plurality of grooves are arranged in parallel on the surface of a substrate having an electro-optic effect, and a plurality of required convex portions are provided, and the upper surface of the convex portion is a light transmitting surface. It is characterized in that notches are provided at both ends of the top surface, and the portion excluding the notches is a light-transmitting surface, or further, the groove is step-shaped, and a groove is formed on both sides of the convex portion from the bottom of the groove. The present invention is an optical shutter element characterized in that at least one rising step portion is formed.

In other words, in this invention, after forming the convex portion in advance with dimensions that are easy to process, a required width (WO) is formed at both ends of the upper surface of the convex portion according to the required width (W) of the light transmitting surface. A notch can be provided to form a light-transmitting surface with a width (W), making it easy to process and reducing damage to the convex portion and processing distortion.

Further, in a structure in which the distance between adjacent convex portions is limited and the dimensional ratio W/H of the convex portions becomes inevitably small, and the effect of the notch portion alone cannot achieve the purpose, By forming a step or part of the required dimensions on both sides of the base of the so-called 4-shaped convex part near the bottom, the thickness of the convex part is substantially increased and the processing distortion that occurs in this vicinity is reduced. The structure also reduces leakage light.

Structure of the Invention The substrates used in this invention include PLZT, LiNb0a, and B11 having electro-optic effects such as Pockels effect.
A known ceramic substrate such as 2Si020 can be used.

In recent years, as optical shutter elements, the width (W) of the light transmitting surface is about 30 to 1100j1, and the height (H) of the convex part is about 1
Those with a size of about 00 to 500 Jlrn are often used.

However, in an optical shutter element having a configuration in which the dimensional ratio (W/H) of the convex portion exceeds 0.5, it is relatively less susceptible to the effects of processing distortion and the above-mentioned problems are less likely to occur.
This is particularly effective in an optical shutter element having a configuration in which H≦0.5.

The width (WO) of the notch formed at both ends of the upper surface of the convex portion is determined by the required width (W) of the light transmitting surface.
The depth (1) of the notch is not a factor in determining the width (W) of the light transmitting surface. The electrode metal film in the notch may or may not be coated.

The dimensions W of the stepped portions formed on both sides of the convex portion in the parallel direction of the convex portions do not necessarily have to be the same size, but the groove bottom width of each convex portion is W + 2w, and the same width portion is h higher than the bottom. In the stepped portion, it is preferable that W≦115W and h≦2/3H be satisfied.

In other words, if W exceeds 115W, the effect of providing the stepped portion will not improve much, and the width of the entire convex portion will become substantially thicker, and the distance between adjacent convex portions will be limited. It becomes difficult to form many light transmitting surfaces in the area where the light is transmitted.

It is desirable to select it appropriately depending on the material of the substrate, the value of the dimensional ratio (W/H) of the convex portion, the required strength characteristics, etc.

Furthermore, the distance between the electrodes arranged on both sides of the convex portion is increased, which is not preferable from the viewpoint of reducing drive voltage.

The height (h) of the stepped portion is appropriately selected depending on the value of the dimensional ratio (W/H) of the convex portion, etc., but it is usually 2/3 or less of the convex portion height H, and even 1/2 or less. A sufficient effect can be obtained.

The shape of the stepped portion is not limited to a rectangular cross-sectional shape as in the embodiments described below, and may be formed into a so-called tapered shape in which the lower part is wider than the upper portion of the stepped portion, or may be multi-staged, etc. The maximum thickness and maximum height are selected within the above-mentioned ranges.

The optical shutter element of this invention includes Ni, Cu, Au.
Known metals for electrodes, such as, can be used.

In particular, when forming electrodes, the optical shutter element of the present invention having a light transmitting surface with an extremely small area can be obtained by adopting the method previously proposed by the present inventor (Japanese Patent Application No. 63-249527). can be provided stably.

That is, after applying a resist I to the surface of a plate-shaped substrate which has been mirror-finished in advance, the uneven portion having the above-mentioned shape is formed.

After that, by electroless plating, a metal film for electrodes such as 7Ni with a thickness of about 1 to 32 mm is deposited on the substrate surface from which the resist has been removed in the above processing, and the resist remaining on the substrate surface is further coated. It is removed by chemical treatment to obtain a light shutter element with a desired shape.

According to this method, since a substrate that has been mirror-finished in advance is used, there is no need to mirror-finish the light-transmitting surface after processing it into the required shape and dimensions, so even if the light-transmitting surface is minute, it will not be damaged. This is effective for manufacturing the optical shutter element of the present invention.

Based on the Drawings (Disclosure of the Invention) FIGS. 1 and 2 are perspective explanatory views showing the structure of an optical shutter element according to the present invention.

Although the drawing shows the simplest configuration,
The present invention can also be applied to optical shutter elements having more complicated configurations. Furthermore, in the drawings, the uneven portions, stepped portions, etc. formed on the substrate are exaggerated.

Structure J: On the surface of the substrate (1) having an electro-optical effect, use a peripheral cutter or the like to form the required grooves (2) and convex portions (3) into the desired uneven shape, and further, form the convex portions (3). A notch (5) consisting of a width (WO) and a depth C1) is provided at a portion of both ends of the upper surface, and the convex portion (3) excluding the notch (5) is turned into a light transmitting surface (4). It is said that

Here, the ratio (W/H) between the height (H) of the convex portion (3) and the width (W) of the light transmitting surface (4) is 0.5 or less.

A groove-shaped electrode is formed by depositing a required electrode material (6) on the side of the protrusion (3) including the notch (5).

In configuration 1, only the upper side ends of the convex part (3) are required to have the required width (W) of the light transmitting surface (4) after finishing it in advance to a size that is easy to process. Width of dimensions (WO)
Since it is only necessary to make a notch, machining is extremely easy, and damage during machining can be significantly reduced.

In the configuration 1 shown in FIG. 1, the groove portion (2) is further processed into a stepped shape during the processing, in other words, the convex portion (3)
A stepped portion (7) is formed which rises from the bottom of the groove portion (2).

The stepped portions (7) are provided on both sides of the convex portion (3), and are provided on both sides of the convex portion (3).
) It is a stepped portion consisting of a width (W) direction dimension (w) and a height (b, ).

A groove-shaped electrode is formed by depositing a desired electrode material (6) on the sides of the convex portion (3) including the stepped portion (7).

Due to the effect of this stepped portion, processing distortion occurring within the convex portion (3) is reduced, and most of the light (not shown) incident from the light transmitting surface (4) on the top surface of the convex portion (3) does not leak. , and is efficiently polarized by the electric field formed between the electrodes (6×6) on both sides of the convex portion (3), and is led out from the flat end surface (lower surface in the figure) of the substrate (1).

These configurations are particularly effective when increasing the dot density of an optical printer, although it is necessary to reduce the shape of each light-transmitting surface.

Examples Example 1 PL expressed as a substrate with a composition ratio of 9/65/35
An optical shutter element according to the present invention (Fig. 1,
An optical shutter element having a conventional structure (FIG. 2) and a conventional structure (FIG. 3) was manufactured.

The groove-shaped electrode was formed as a Ni plating layer with a thickness of about 1 by electroless plating.

Note that the grooves were processed using a peripheral blade cutter with a thickness of 401 tm.

Dimensions common to each configuration W=601imSH=200. m The notch outside method according to this invention is wo=57□n□, l
= 5. ,, The dimensions of the tiered part are w = 5pm, h =
It is 11007z.

Example 2 When a laser beam of λ=633 nm was incident on these optical shutter elements and the leakage light was measured, the leakage light was about 4% in the conventional structure shown in FIG. In the structure of the present invention shown in FIG. 2, leakage light was significantly reduced to about 1.5% and 1%.

[Brief explanation of drawings]

FIGS. 1 and 2 are perspective explanatory views showing the structure of an optical shutter element according to the present invention. FIG. 3 is a perspective explanatory view showing the configuration of a conventional optical shutter element. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Groove part, 3... Convex part, 4... Light transmission surface, 5... Notch part, 6... Electrode material, 7...
・Step part. fortune-telling

Claims (1)

[Scope of Claims] 1. An optical shutter element in which a plurality of grooves are arranged in parallel on the surface of a substrate having an electro-optic effect and a plurality of required convex portions are provided, and the upper surface of the convex portion is a light transmitting surface, comprising: An optical shutter element characterized in that notches are provided at both end portions, and the portion excluding the notches is a light transmitting surface. 2. In an optical shutter element in which a plurality of grooves are arranged in parallel on the surface of a substrate having an electro-optic effect and a plurality of required convex portions are provided, and the upper surface of the convex portion is a light transmitting surface, the groove portion is formed into a step shape, and the convex portion is At least one stepped portion rising from the bottom of the groove is formed on both sides of the convex portion, and notches are provided at both end portions of the upper surface of the convex portion, and the portion other than the notch portion is a light transmitting surface. Characteristic optical shutter element.