JPH07120780A - Spatial optical modulation element and optical device - Google Patents

Abstract

PURPOSE:To enhance the utilization efficiency of light. CONSTITUTION:A conjugate substance 105 having the multilayer structure of liquid crystal and high molecular material and capable of reflecting the light of a specified wavelength band and electrically controlling reflection intensity; a light shielding film 106 consisting of high-molecular material in which pigment is dispersed; and a photoconductive film 107 consisting of BSO are interposed between transparent substrates 101 and 102 consisting of glass and the high- molecular material, where transparent electrodes 103 and 104 consisting of ITO are formed. Then, a power source 108 for impressing voltage is connected to the electrodes 103 and 104.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical writing type spatial light modulator having high light utilization efficiency and an optical device using the same.

[0002]

2. Description of the Related Art Conventionally, an optical writing type spatial light modulator has been used to realize a bright projection type display device.

FIG. 14 is a schematic sectional view showing a conventional spatial light modulator. As shown in the figure, the glass substrate 120
1, 1202, transparent electrodes 1203, 1204, a photoconductive film 1208, a dielectric mirror 1205 that reflects the reading light 1211, and a liquid crystal 1 that controls the polarization direction of the reading light 1211.
206, a light shielding film 1207 for separating the reading light 1211 and the writing light 1210 is sandwiched, and a power source 1209 is connected to the transparent electrodes 1203 and 1204.

In this spatial light modulator, when the writing light 1210 having image information is applied to the photoconductive film 1208, the resistance of the photoconductive film 1208 changes due to the pattern of the image information, and the photoconductive film 1208. The voltage applied to the liquid crystal 120
6, and a voltage is applied to the liquid crystal 1206 in the same pattern as the image information. Since the liquid crystal 1206 can control the polarization direction of light by a voltage, the read light 12
The polarization direction of 11 can be changed according to the pattern of the image information of the writing light 1210. As a result, the dielectric mirror 1
The polarization state of the reading light 1212 reflected from 205 is modulated by the pattern of the image information of the writing light 1210, and when the reading light 1212 reflected through the polarization element is detected, the writing light 1
Readout light 1212 corresponding to the pattern of image information 210 is obtained.

[0005]

However, in such a spatial light modulator, only light of a specific polarization can be used, and in an optical device using this spatial light modulator, one polarization is wasted.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a spatial light modulator having a high light utilization efficiency and an optical device using the same.

[0007]

In order to achieve this object, in the present invention, in a spatial light modulator, a first transparent substrate on which a transparent electrode is formed, a transparent electrode and a photoconductive film are formed. A composite having a multilayer structure of a birefringent material and a non-birefringent material that does not exhibit birefringence is sandwiched between the second transparent substrate and the second transparent substrate.

In the optical device, the spatial light modulation element, the image device, and the light source are formed, and the optical image information from the image device is projected on the spatial light modulation element to form the spatial light modulation element. The light emitted from the light source is modulated.

[0009]

In this spatial light modulator and optical device, no polarizing plate is required, and the reflection and transmission of all polarized light in a specific wavelength band can be controlled.

[0010]

【Example】

(Spatial Light Modulation Element) FIG. 1 is a schematic sectional view showing a spatial light modulation element according to the present invention. As shown in the figure, for example, I
First and second transparent substrates 1 made of, for example, glass or polymer material, on which transparent electrodes 103, 104 made of TO are formed
Between 01 and 102, a multi-layer structure of a liquid crystal that is a birefringent material whose refractive index changes with an electric field and a polymer material that is a non-birefringent material that does not exhibit birefringence is provided. A composite 105 capable of reflecting light and electrically controlling the reflection intensity, a light-shielding film 106 made of, for example, a polymer material in which a pigment is dispersed, and a photoconductive film 107 made of, for example, BSO.
, And a power supply 108 for applying a voltage is connected to the transparent electrodes 103, 104. Note that the complex 105
An outline of the structure of is shown in FIGS. 4 (a) and 4 (c). Liquid crystal 4
01 and the polymer material 402 are arranged in parallel to the device surface, and reflect light that is vertically incident in the vertical direction. The composite shown in FIG. 4 (a) has a constant periodic structure of the liquid crystal 401 and the polymer material 402 and reflects a relatively narrow wavelength band, and thus the composite shown in FIG. 4 (c). Is liquid crystal 40
The periodic structure of 1 and the polymer material 402 has a plurality of periods and reflects a wide wavelength band.

In this spatial light modulator, the writing light 1
When 09 is irradiated, the resistance of the photoconductive film 107 changes corresponding to the pattern of the image information of the writing light 109, and the voltage is applied to the composite 105 by the pattern. As a result, the reading light 11
0 is modulated by the composite 105 and the modulated read light 111
Is output. The light that is not modulated is absorbed by the light shielding film 106.

In such a spatial light modulator, since the polarizing plate is not required and the reflection and transmission of the light of the specific wavelength band of all the polarized light can be controlled, the light utilization efficiency can be improved.

FIG. 2 is a schematic sectional view showing another spatial light modulator according to the present invention. As shown in the figure, for example, IT
First and second transparent substrates 20 made of, for example, glass or polymer material, on which transparent electrodes 203, 204 made of O are formed.
A composite 205, which is composed of a multi-layered structure of a liquid crystal and a polymer material, is capable of reflecting light in a specific wavelength band and electrically controlling the reflection intensity, and a mirror 206 for reflecting light.
And a light-shielding film 2 made of, for example, a polymer material in which a pigment is dispersed.
07 and a photoconductive film 208 made of, for example, BSO are held between the transparent electrodes 203 and 204, and a power source 209 for voltage application is connected to the transparent electrodes 203 and 204. An outline of the structure of the composite body 205 is shown in FIGS. 4 (b) and 4 (d). The composite body 205 is different from the composite body 105 used in the spatial light modulation element shown in FIG. 1 in that the liquid crystal 401 and the polymer material 402 are arranged so as to be inclined with respect to the element surface, and the vertically incident light is directed obliquely. It is designed to reflect. Further, the composite shown in FIG. 4 (b) has a constant periodic structure of the liquid crystal 401 and the polymer material 402 and reflects a relatively narrow wavelength band, and the composite shown in FIG. 4 (d) is The periodic structure of the liquid crystal 401 and the polymer material 402 has a plurality of periods and reflects a wide wavelength band.

In this spatial light modulator, the writing light 2
When 10 is irradiated, the resistance of the photoconductive film 208 changes corresponding to the pattern of the image information of the writing light 210, as in the spatial light modulator shown in FIG. Is applied. As a result, the read light 211 that is obliquely incident is modulated by the composite 205 and output as the read light 212. Further, the read light 213 not reflected by the composite 205 is not absorbed inside the element but reflected by the mirror 206, so that unnecessary heating due to light absorption inside the spatial light modulator can be prevented.

FIG. 3 is a schematic sectional view showing another spatial light modulator according to the present invention. As shown in the figure, for example, IT
First and second transparent substrates 30 made of, for example, glass or polymer material on which transparent electrodes 303 and 304 made of O are formed
A composite 305 having a multi-layer structure of a liquid crystal and a polymer material between 1 and 302, capable of reflecting light in a specific wavelength band and electrically controlling reflection intensity, and a composite 305 for reflecting light and serving as a light-shielding film. A mirror 306 having a function and a photoconductive film 308 made of, for example, BSO are sandwiched between the transparent electrodes 303, 3
A power source 309 for applying a voltage is connected to 04.
The composite 305 has the structure shown in FIGS. 4 (b) and 4 (d).

In this spatial light modulator, as in the spatial light modulator shown in FIG. 2, the resistance of the photoconductive film 308 changes corresponding to the pattern of the image information of the writing light 310, and the pattern is used. A voltage is applied to the composite 305, and the reading light 311
Are modulated by the pattern of the image information of the writing light 310 by the composite 305 and output as the reading light 312. Further, since the reading light 313 not reflected by the composite 305 is not absorbed inside the element but reflected by the mirror 306, unnecessary heating due to light absorption inside the spatial light modulator can be prevented, and Since the mirror 306 also has a function as a light-shielding film, the structure can be simplified.

In the above embodiment, the liquid crystal 401 and the polymer material 402 are completely separated into layers as shown in FIG. 4, but as shown in FIG. -Shaped liquid crystal 501 may be arranged in the polymer material 502, and the refractive index distribution may be formed in layers. That is, if the refractive index changes due to the liquid crystal and the polymer material are periodically formed, it is possible to reflect light of a specific wavelength.

The composite having a multilayer structure of liquid crystal and polymer material used in the spatial light modulator according to the present invention can be easily manufactured by using the interference pattern of laser light.

FIG. 6 is a schematic explanatory view of a method of forming the spatial light modulator as shown in FIG. First, as shown in FIG. 6A, a nematic liquid crystal (E-7 manufactured by Merck & Co., Inc.) and a photocurable resin (Lux Track LCR509A manufactured by Adell Co., Ltd.) are provided on a glass substrate 601 on which a transparent electrode 602 made of, for example, ITO is formed. ) And mixed solution 603 are applied. Next, as shown in FIG. 6B, for example, argon laser beams 604 and 605 having a wavelength of 488 nm are irradiated. At this time, the laser beams 604 and 605 interfere with each other, and the mixed solution 603.
A light interference pattern 606 is generated inside. The photo-curable resin is cured corresponding to the interference pattern 606, and a multilayer structure composed of the liquid crystal 607 and the polymer material 608 is formed as shown in FIG. 6C. Next, as shown in FIG. 6D, for example, the light-shielding film 6 made of a polymer material in which a pigment is dispersed is formed.
09, for example a photoconductive film 610 made of BSO, for example I
Glass substrate 6 on which transparent electrode 611 made of TO is formed
Paste 12

In the spatial light modulator thus formed, the wavelength 488n of the white light incident from the vertical direction is
Light near m can be strongly reflected and read light can be modulated by write light.

Although the spatial light modulator as shown in FIG. 1 has been described in the above embodiment, the mirror, the light shielding film, the photoconductive film and the transparent electrode are formed at the stage shown in FIG. 6D. If a glass substrate is attached, the spatial light modulator as shown in FIG. 2 can be formed. Also, FIG. 6 (d)
When the glass substrate on which the mirror, the photoconductive film, and the transparent electrode are formed is attached at the stage shown in FIG. 3, the spatial light modulator as shown in FIG. 3 can be formed.

Further, in the above-mentioned embodiment, the cured product of Lux Track LCR509A manufactured by Adell Co. was used as a raw material of the polymer material which is a non-birefringent material, and E-7 manufactured by Merck was used as the liquid crystal. The present invention is not limited to this, and a liquid crystal and a polymer material in which the refractive index of the liquid crystal is different from that of ordinary light and extraordinary light and the refractive index of the polymer material may be used.

Although nematic liquid crystal is used as the birefringent material in the above embodiments, the invention is not limited to this, and polymer liquid crystal or ferroelectric liquid crystal may be used as the birefringent material.

Further, in the above-mentioned embodiment, an example in which the liquid crystal and the polymer material are separated into layers is shown, but it is not essential that the liquid crystal and the polymer material are separated into layers as described above, and the birefringent material and A structure in which the refractive index is periodically modulated by the birefringent material may be used.

Further, in the above embodiment, only the argon ion laser beams 604 and 605 having the wavelength of 488 nm were used in the formation of the spatial light modulator, but the present invention is not limited to this, and a plurality of light sources causing interference of light are used. Alternatively, for example, when helium-neon laser light having a red wavelength is irradiated at the same time, a multi-layer structure of a liquid crystal that reflects red light and a polymer material can be simultaneously manufactured.

Further, in the above-mentioned embodiment, the periodic structure of the liquid crystal and the polymer material is formed parallel to the transparent substrate surface. However, by changing the direction and shape of the interference pattern of the laser light, the light can be emitted in various directions. It is possible to form a periodic structure that reflects light. For example, as shown in FIG. 7, by changing the irradiation angle θ1 of the laser beams 702 and 703 and the inclination angle θ2 of the sample 701, the period d of the periodic structure and the inclination of the periodic structure can be easily controlled.

(Optical Device) FIGS. 8 and 9 are schematic views showing a projection type display using the spatial light modulator according to the present invention. As shown in the figure, this projection display has spatial light modulators 801a and 801b, a writing light lens 802, a video device 803 for generating writing light, a light source 804 for reading light, and a projection lens 805. ing. The spatial light modulation element 801a of the projection display shown in FIG. 8 is a spatial light modulation element that reflects modulated light in the same direction as the reflection on the element surface, for example, the spatial light modulation element shown in FIG. The spatial light modulation element 801b of the projection display shown in FIG. 9 is a spatial light modulation element that reflects modulated light in a direction different from the reflection on the element surface, for example, the spatial light modulation element shown in FIGS.

In this projection type display, the writing light from the image device 803 modulates the all-polarized reading light from the light source 804, and the light in a specific wavelength band is projected by the projection lens 80.
It is projected on a screen (not shown) via the screen 5. Therefore, it is possible to obtain a bright projection image by the light of the specific wavelength band.

FIG. 10 is a schematic view showing a color projection display using the spatial light modulator according to the present invention, FIG.
FIG. 11 is a diagram showing a part of the color projection display shown in FIG. 10. As shown in the figure, this projection type display has a light modulator 901, a white light source 902, a red light reflection dichroic mirror 903, a green light reflection dichroic mirror 904, a blue light reflection dichroic mirror 905, and a projection screen 910. The light modulator 901 has a spatial light modulator 908 as shown in FIG. 1, a writing light lens 907, a video device 906 for generating writing light, and a projection lens 909.

In this color projection type display, the light from the white light source 902 for generating the reading light is red light reflecting dichroic mirror 903, green light reflecting dichroic mirror 904, and blue light reflecting dichroic mirror 905.
Are split into red light, green light, and blue light, and are input to the light modulators 901 for red light, green light, and blue light. The input light is modulated by the respective light modulators 901, and the projection screen 90
6 and a color image is obtained.

FIG. 12 is a schematic view showing another color projection display using the spatial light modulator according to the present invention, and FIG. 13 is a view showing a part of the color projection display shown in FIG. As shown in the figure, this projection type display has a light modulator 1001, a white light source 1002 for generating readout light, and a screen 1003. The light modulator 1001 has a space as shown in FIGS. Light modulator 1
101R, 1101G, 1101B, writing light lens 1
102, a video device 1103 for generating writing light, a projection lens 1105, a mirror 1106, and a light absorber 1107.

In this color projection display, white light from the white light source 1002 is input to the spatial light modulator 1101R that acts on red light to obtain modulated light. Further, the remaining light is input through the mirror 1106 to the spatial light modulator 1101G that acts on the green light to obtain modulated light. Further, the remaining light is input via the mirror 1106 to the spatial light modulator 1101B that acts on blue light to obtain modulated light.
The finally remaining light is absorbed by the light absorber 1107. A color image can be obtained by mixing the modulated red light, green light, and blue light on the screen 1003 or on the optical path in the middle.

In such a color projection display, since the number of dichroic mirrors can be reduced, the device structure can be simplified.

In the above-mentioned embodiment, the basic optical system is used. However, various conventionally used optical systems may be used, and the feature of the present invention is the spatial light modulation shown in FIG. It is in using the element.

In the above embodiment, three types of spatial light modulators that reflect red light, green light and blue light are used,
Although it was a color projection display that obtains a full-color display, it is not limited to this configuration in multi-color display.
It suffices to use two or more types of spatial light modulators that reflect light in different wavelength bands.

Although the projection type display has been described in the above embodiments, the present invention can be applied to an optical device such as an optical switch.

Further, in the embodiment shown in FIGS. 12 and 13, the light finally remaining was absorbed by the light absorber 1107, but the light finally remaining was again reflected by the white light source 100 by the mirror.
You may return to the 2 side.

[0038]

As described above, in the spatial light modulator and the optical device according to the present invention, since the polarizing plate is not necessary, it is possible to control the reflection and the transmission of the light of the specific wavelength band of all the polarized light. The light utilization efficiency can be increased. As described above, the effect of the present invention is remarkable.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a spatial light modulator according to the present invention.

FIG. 2 is a schematic sectional view showing another spatial light modulator according to the present invention.

FIG. 3 is a schematic sectional view showing another spatial light modulator according to the present invention.

FIG. 4 is a cross-sectional view showing a composite body having a multilayer structure of liquid crystal and a polymer material.

FIG. 5 is a cross-sectional view showing a composite body having a multilayer structure of liquid crystal and a polymer material.

FIG. 6 is a schematic explanatory diagram of a method for forming a spatial light modulator according to the present invention.

FIG. 7 is a schematic explanatory diagram of a method for forming a spatial light modulator according to the present invention.

FIG. 8 is a schematic view showing a projection type display using a spatial light modulator according to the present invention.

FIG. 9 is a schematic view showing another projection type display using the spatial light modulator according to the present invention.

FIG. 10 is a schematic view showing a color projection display using the spatial light modulator according to the present invention.

11 is a diagram showing a part of the color projection display shown in FIG.

FIG. 12 is a schematic view showing another color projection display using the spatial light modulation element according to the present invention.

13 is a diagram showing a part of the color projection display shown in FIG.

FIG. 14 is a schematic sectional view showing a conventional spatial light modulator.

[Explanation of symbols]

 101, 102 ... Transparent substrate 103, 104 ... Transparent electrode 105 ... Complex 107 ... Photoconductive film 201, 202 ... Transparent substrate 203, 204 ... Transparent electrode 205 ... Complex 208 ... Photoconductive film 301, 302 ... Transparent substrate 303, 304 ... Transparent electrode 305 ... Composite 308 ... Photoconductive film 801a, 801b ... Spatial light modulator 803 ... Image device 804 ... Light source 901 ... Light modulator 902 ... White light source 906 ... Image device 908 ... Spatial light modulator 1001 ... Light Modulator 1002 ... White light source 1103 ... Imaging device

Claims (2)

[Claims] 1. A first transparent substrate having a transparent electrode formed thereon,
A composite having a multilayer structure of a birefringent material and a non-birefringent material that does not exhibit birefringence is sandwiched between a transparent electrode and a second transparent substrate on which a photoconductive film is formed. Spatial light modulator. 2. The spatial light modulation element according to claim 1, an image device, and a light source. The optical image information from the image device is projected onto the spatial light modulation element to irradiate the spatial light modulation element. An optical device for modulating light from the above described light source.