JPH02248921A - Optical phase modulating element - Google Patents

Abstract

PURPOSE:To obtain a clear video by arraying electrodes in parallel on the surface of a substrate which has electrooptic effect and arranging exposed optical element in a flat-plate shape so that the electric field directions of adjacent elements are different from each other. CONSTITUTION:One plane plate is constituted by arranging a couple of optical elements 11 and 13 in parallel and the electrodes 12 and 14 are arrayed in parallel and exposed on the substrate surface. Then the laminating directions of the electrodes 12 and 14 are intersected orthogonally with each other so that the electric field directions are intersected orthogonally with each other. Namely, the electric field directions of the couple of optical elements 11 and 13 are intersected orthogonally with each other, so the influence of the light diffraction of those optical element is reduced. Consequently, image parts in an X and a Y direction never become unclear and the clear video is formed on a screen 6.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application This invention relates to an optical phase modulation element constituting an optical phase modulator used in stereoscopic televisions, optical changeover switches, etc. An optical phase modulation element that is configured by arranging a plurality of optical elements that are exposed by arranging them in parallel, for example, so that the electric field directions are orthogonal, and that can modulate and transmit clear images and significantly improve the stereoscopic effect on stereoscopic televisions, etc. Regarding.

An optical phase modulation element that utilizes the electro-optic effect is used to block, select, and convert incident light on an optical transmission line.
LaXZrTi)03, LiNbO3, B112Si0
It is made of a ceramic substrate such as No. 20, and is constructed by arranging optical elements whose electric field direction forms an intersection angle of 45 degrees with the polarization direction (electric field direction) of incident light. are being considered for application.

FIG. 4 shows an example in which an optical phase modulation element is used in a three-dimensional television.

That is, the light (image) emitted from the light source (CRTXI) enters the polarizing plate (4) through the lens (2x3), but at this time, only light having an electric field in a predetermined direction is transmitted and the light is transmitted through the optical element. (5) is reached.

Furthermore, the light incident on the optical element (5)
When a predetermined voltage is applied to the screen (6), due to the electric field formed between each electrode, the direction of the electric field of the light is rotated by 90 degrees and transmitted, reaching the screen (6).

Problems with the Prior Art Background Art For example, assuming a case where a cross image is emitted from a light source (CRTXI), the perspective view of FIG. 5 schematically shows the optical path of the light passing through the optical element (5). The explanation will be based on an explanatory diagram.

The optical element (5) shown in FIG. 5 is made by alternately laminating and fixing a strip-shaped substrate element (7) having an electro-optic effect and an electrode (8) made of metal foil such as Ni. It has a so-called laminated electrode configuration in which the electrodes penetrate in the direction of the light transmitting surface.

The optical element (5) having this configuration forms an electric field in the Y direction in the figure by applying a voltage to each electrode (8).

Here, the light that has passed through the polarizer (see number 4 in Figure 4) (
When the image (image) is a cross as shown in the figure, the portion in the X direction (the shaded area in the figure) of the image that passes through the optical element (5) having the laminated electrode structure and is formed on the screen (6) is very large. It has been confirmed that the image becomes unclear.

Furthermore, although not shown, when using an optical element in which the electric field direction is formed in the X direction in FIG. The black area in Figure 5) becomes very unclear.

As mentioned above, in the conventional configuration using an optical element in which the electric field direction is limited to one direction, the image in the direction perpendicular to the electric field direction becomes unclear, making it difficult to obtain the three-dimensional effect originally required for three-dimensional television. However, there has been a strong desire to improve the structure of such optical devices.

Furthermore, in addition to optical devices having the laminated electrode structure shown in FIG. 2a and FIG. In any of the known optical elements, such as an electrode configuration (see Figure 2) or a so-called planar electrode configuration (see Figure 2C) in which a metal film is deposited on the surface of a substrate by sputtering or the like. The above phenomenon occurs in an optical phase modulator that uses an optical element that has a configuration in which multiple electrodes are arranged in parallel and exposed on the substrate surface (light-transmitting surface), and the electric field direction is limited to one direction. It was confirmed.

Purpose of the Invention The present invention is proposed in view of the above-mentioned current situation, and is a method to completely uniformly modulate all the light (image) incident on the light transmission surface of an optical phase modulation element regardless of the difference in the part of the light transmission surface. The object of the present invention is to provide an optical phase modulation element that can provide clear images with a three-dimensional effect, especially when used in a three-dimensional television.

Summary of the Invention As a result of a detailed study of the configuration of the optical element (5) shown in FIG. , the optical element (5)
It was confirmed that the light passing through is affected by optical diffraction, resulting in a part of it becoming unclear.

It is presumed that this is also caused by the influence of light diffraction in optical elements having a planar electrode configuration or a groove-type electrode configuration.

Therefore, the inventor divided the light transmission surface of each of the above optical elements into multiple parts, and devised an arrangement of electrodes so that the direction of the electric field generated in each divided part was different, thereby reducing the effect of light diffraction. For example, they found that if a pair of adjacent optical elements are arranged in a plate-like configuration so that the electric field directions are orthogonal to each other, the desired clear image can be obtained, and the present invention has been made. completed.

That is, the present invention is characterized in that optical elements each having a plurality of electrodes arranged in parallel and exposed on the surface of a substrate having an electro-optic effect are arranged in a flat plate shape such that the electric field directions of adjacent elements are different from each other. This is an optical phase modulation element.

Based on the Drawings (Disclosure of the Invention) FIGS. 1A to 1D show an embodiment of an optical phase modulation element according to the present invention constructed using an optical element having a laminated electrode structure.

FIGS. 2a-2c are perspective explanatory views of the optical element.

FIG. 3 is a perspective view schematically showing the state of light passing through the optical phase modulation element according to the present invention.

Structure The optical phase modulation element (10) shown in Figure 1a is a pair of optical phase modulators each having an area as wide as dividing the light transmitting surface of an optical element used in a conventional optical phase modulator into two in the left and right direction in the figure. Optical element (11
A plurality of electrodes (12 x 14) are arranged in parallel and exposed on the surface of each substrate. The stacking directions are orthogonal.

In figure a, the direction of the electric field formed in the optical element (11) is in the vertical (Y) direction in the figure, and the direction of the electric field formed in the optical element (13) is in the left-right (X) direction in the figure.

The optical phase modulation element (20) in the same figure consists of a pair of optical elements (21 x 22) as in Fig. 1, but each has an area as wide as dividing the light transmitting surface into two in the vertical direction in the figure. However, the electric field directions of adjacent elements are arranged in parallel to each other in a flat plate shape, and the direction of the electric field formed in the upper optical element (21) is the vertical (Y) direction in the figure, and the direction of the electric field formed in the lower optical element (22) is ) is the direction of the electric field formed in the left-right (X) direction in the figure.

The optical phase modulation element (30) in Figure C consists of 16 optical elements (31 x 32
)...(35X36)...(1 in the figure)
(only portions are shown), which are arranged in parallel in a flat plate shape so that the electric field directions of adjacent elements are orthogonal to each other.

That is, the light transmission surface of the optical phase modulation element (30) is divided into 16 parts, but for example, considering only the four surfaces shown in the figure, the direction of the electric field formed in the optical element (31X36) and (32X35) is Since they are the same, it is possible to obtain substantially the same effect as the configuration shown in FIGS. 1 and 2 in which the light transmitting surface is divided into two.

Theoretically, it is possible to improve the clarity of the -layer image by increasing the number of divisions as much as possible, but when it comes to implementation, each optical element becomes smaller and the assembly, such as wiring to electrodes, becomes more complicated. Not only this, but also an increase in light leakage from adjacent optical elements is caused, so it is desirable to select the number of divisions as appropriate depending on the required dimensions, optical characteristics, etc.

The optical phase modulation element (40) shown in Fig. 1d consists of a pair of optical elements (41 x 43) having an area as wide as the light transmitting surface divided into two in the left and right direction in the same way as in Fig. 1a. However, the elements are arranged in parallel in a flat plate shape so that the electric field directions of adjacent elements are different from each other.

Furthermore, a plurality of electrodes (42x44) are arranged in parallel and exposed on the surface of each substrate of the pair of optical elements (41x43).
Although the stacking direction of each electrode (42×44) is inclined by 45e' with respect to the vertical line in the figure, the electric field directions are orthogonal to each other.

The optical phase modulation element (40) having such a configuration is also shown in FIGS. 1a and 1b.
It has the same effect as the configuration shown in the figure, and can also be configured with a large number of divisions as in the above-mentioned figure 0.

Alternatively, in the configuration shown in Fig. 0, some of the small optical elements are arranged in combinations of electric field directions as shown in Fig. d, and arranged in parallel in a flat plate shape so that the electric field directions of adjacent elements are different from each other. It is also good to say.

In this invention, at least a pair of optical elements each having a plurality of electrodes arranged in parallel and exposed on the surface of a substrate having an electro-optic effect are each made of (PbLaXZrTi)Os(
(hereinafter referred to as PLZT), LiNbO3, B112Si0
A known ceramic substrate having an electro-optic effect such as No. 20 can be used, and the electrodes exposed on the surface can also be provided by various methods.

For example, as shown in Figure 2a, a strip-shaped substrate element (
51) and metal foil electrodes (52) such as Ni are alternately laminated and fixed, and the electrode (52) penetrates in the direction of the light transmitting surface. 53)
Grooves (54) are provided on the surface at predetermined intervals, and the grooves (54)
An optical element with a so-called groove electrode structure, in which an electrode (55) made of a conductive paste or a metal film such as Cu is provided on the surface of the substrate (56), or as shown in FIG.
It is possible to employ a known optical element, such as an optical element having a so-called plane electrode structure, in which a plane electrode (57) of a metal film such as Cu is deposited by vapor deposition or sputtering.

Effects and Effects When the optical phase modulation element according to the present invention shown in FIG. 1A of the above-described configuration is adopted in a stereoscopic television, as shown in FIG. 3, the light ( The image (image) passes through both of the pair of optical elements (11×13) and reaches the screen (6).

Since the directions of the electric fields of the pair of optical elements (11 x 13) are orthogonal to each other, the influence of light diffraction of each optical element is reduced, and the image in either the left/right (X) direction or the up/down (Y) direction in the figure is The screen (
6) A clear image can be formed on the screen.

Example A 2-thick Ni electrode was sandwiched between a number of PLZT substrates so that the distance between the electrodes was 0.5 mm and the thickness (light path length) was 0.5 mm. The conventional optical phase modulation device shown in the figure was fabricated.

In addition, the distance between the electrodes is 0.5 mm, and the thickness (optical path length) is 0.5 mm.
Two bullets of N between a large number of PLZT substrates so that
A light transmitting plane with dimensions of 50 mm x 25 mm is placed between the i-electrodes, and the lamination direction of the electrodes is set in the longitudinal direction of 50 mm, and the lamination direction of the electrodes is set in the short side direction of 25 mm. An optical phase modulation element having the same configuration as that in Figure 1a was fabricated.

When each of the above elements was used in a projector, in the case of the conventional element, the resolution in the horizontal direction was reduced to about 175 in the vertical direction, as in the case of FIG.

On the other hand, in the case of the element according to the present invention, the vertical and horizontal resolutions were approximately the same, and extremely clear images were obtained.

[Brief explanation of drawings]

FIGS. 1A to 1D show an embodiment of an optical phase modulation element according to the present invention constructed using an optical element having a laminated electrode structure. FIGS. 2a-2c are perspective explanatory views of the optical element. FIG. 3 is a perspective view schematically showing the state of light passing through the optical phase modulation element according to the present invention. FIG. 4 is an explanatory diagram of the optical path when the optical phase modulation element is employed in a three-dimensional television. FIG. 5 is a perspective view schematically showing how light passes through a conventional optical element. 1... Light source, 2, 3... Lens, 4... Polarizer,
5... Optical element, 6... Screen, 10, 20, 3
0,40... Optical phase modulation element, 11.13,21,2
2, 31, 32, 35, 36... optical element, 12.14
, 42, 44...electrode.

Claims (1)

[Claims] 1. Optical elements in which a plurality of electrodes are arranged in parallel and exposed on the surface of a substrate having an electro-optical effect are arranged in a flat form in such a way that the electric field directions of adjacent elements are different from each other. Characteristic optical phase modulation element.