JPH10170948A - Spatial optical modulation element and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spatial optical modulation element that obviates the peeling of a photoconductive layer, has high performance, and can obtain a good-contrast image with high resolution and a method for producing the same. SOLUTION: This spatial optical modulation element has a pair of light- transmissible substrates 10, 11 facing each other, light-transmissible electrodes 20, 21 disposed on the surfaces of the respective light-transmissible substrates and the photoconductive layer 3 mainly composed of hydrogenated amorphous silicon and an optical modulation member layer 5 held and disposed between the light-transmissible electrodes facing each other. The photoconductive layer 3 has 2 to 60μm thickness and is disposed in the parts exclusive of the entire periphery at the ends of the substrate 10. The photoconductive layer 3 of the spatial optical modulation element may be formed by forming the photoconductive layer 3 having 2 to 60μm thickness in the state of superposing deposited film preventive members so as to cover the entire periphery at the ends of the substrate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatial light modulator for writing information on a light modulation member by an optical signal under application of a voltage, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As for an optical input spatial light modulator used for image processing and display, a device based on a combination of ZnS and twisted nematic (TN) liquid crystal was first reported [Appl. Phys. Lett. 17 (1970) 5
1], and then a combination of CdS and TN liquid crystal [App
l. Phys. Lett. 22 (1973) 90] or an element composed of single crystal silicon and TN liquid crystal [J. Appl.
Phys. 5 (1985) 1356]. In addition, as disclosed in JP-A-49-90155, JP-A-49-21166, JP-A-58-199327, and JP-A-59-216126, light modulation comprising a liquid crystal layer is disclosed. There is known a member having a laminated structure composed of a member and a photoconductive layer formed in a planar and homogeneous manner. In such a spatial light modulator, as a photoconductive layer, JP-A-58-199327 or "A
ppl. Opt. 26 (1987) 241 ", hydrogenated amorphous silicon (a-Si:
H) is advantageously used for reasons such as high sensitivity, high-speed response, ambipolarity, and easy production of a homogeneous film. Such a spatial light modulator inputs information into a photoconductive layer by writing light, and reads a change in a voltage applied to the light modulation member according to a change in impedance of the photoconductive layer as a change in the light modulation member. is there.

[0003] In order to put the above-mentioned spatial light modulation element into practical use, it is important to make the element configuration such that the degree of modulation of the light modulation member is as large as possible. Therefore, the impedance of the photoconductive layer is higher than the impedance of the light modulation member in the dark, and most of the applied voltage is distributed to the photoconductive layer.
At the time of light, it is necessary to lower the impedance of the light modulation member so that most of the applied voltage is distributed to the light modulation member. Therefore, the difference in impedance between the photoconductive layer and the light modulation member is reduced. Larger is more preferable. When a liquid crystal is used as the light modulating member, the impedance is usually in the range of 10 ¹⁰ to 10 ¹¹ Ωcm. Furthermore, it has been reported that the dark resistance of a-Si: H used as a photoconductive layer can be minimized to 10 ¹¹ to 10 ¹² Ωcm by a small amount of boron doping [W. E. FIG. Spear a
nd P.N. G. FIG. LeComber: Phil. Mag.
33 (1976) 935]. Regarding this,
In Japanese Patent Laid-Open No. 199327, a-Si: H doped with 10 to 400 ppm of boron is used.
No. 67196 proposes to use a-Si: H doped with 0.1 to 10 ppm of boron.
Even in this case, in order to obtain a sufficient impedance ratio between the light modulating member layer and the photoconductive layer, the thickness of the photoconductive layer must be equal to or greater than that of the light modulating member layer.

In a conventional spatial light modulator using an amorphous silicon-based photoconductive layer, a photoconductive layer is formed on a light transmitting electrode made of a metal oxide such as tin oxide or tin oxide doped with indium by plasma CVD. Form by the method,
At that time, due to the difference in thermal expansion coefficient between the amorphous silicon and the substrate, the photoconductive layer is warped or peeled off due to the difference in thermal expansion coefficient between the amorphous silicon and the substrate due to heating of the substrate provided with the light-transmitting electrode for film formation and temperature rise due to plasma. The problem is greater as the amorphous silicon photoconductive layer is thicker.

On the other hand, Japanese Patent Application Laid-Open No. 6-337434 proposes to insert a member for adjusting thermal expansion between the substrate and the amorphous silicon photoconductive layer to cancel the warpage. No mention is made of the separation of the amorphous silicon photoconductive layer resulting from the above.

Japanese Patent Application Laid-Open No. Hei 6-265865 discloses that in order to provide a spacer, a film is formed by using a mask so that a photoconductor film is not formed on a transparent substrate on which a transparent electrode film is formed. A liquid crystal spatial light modulator in which a thin liquid crystal layer is formed is described. However, in this case, the difference in thickness between the spacer and the photoconductor is the thickness of the liquid crystal layer, and the thickness of the photoconductor near the mask is likely to be non-uniform. There is a problem that the thickness of the liquid crystal layer varies in the entire device due to the warpage.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art. That is, an object of the present invention is to provide a high-performance spatial light modulation element provided with a photoconductive layer mainly composed of hydrogenated amorphous silicon having a thickness capable of operating the light modulation member layer satisfactorily. To provide. It is another object of the present invention to provide a method for manufacturing the above-described high-performance spatial light modulator.

[0008]

The present inventor has succeeded in solving the above-mentioned problems by adopting the following constitution. That is, the spatial light modulation element for writing information on the light modulation member layer by the optical signal of the present invention includes a pair of opposing translucent substrates, and a translucent electrode provided on the surface of each translucent substrate. A photoconductive layer mainly composed of hydrogenated amorphous silicon and a light modulating member layer provided between the opposing translucent electrodes, wherein the photoconductive layer has a thickness of 2 to 60 μm. Wherein the light-transmitting substrate is provided on a portion excluding the entire periphery of the end portion.

In the method of manufacturing a spatial light modulator according to the present invention, a light-transmitting electrode is formed on a pair of light-transmitting substrates, and the light-transmitting electrode formed on one of the light-transmitting substrates is provided. A photoconductive layer mainly composed of hydrogenated amorphous silicon and a light modulating member layer are sequentially formed thereon, and the light transmitting member formed on the surface of the other light transmitting substrate is in contact with the light modulating member layer. When forming a photoconductive layer mainly composed of hydrogenated amorphous silicon on a light-transmitting substrate on which a light-transmitting electrode is formed, the entire edge of the light-transmitting substrate is formed. A photoconductive layer having a film thickness of 2 to 60 [mu] m is formed in a state where the deposition preventing member is stacked so as to cover the periphery.

In the spatial light modulator of the present invention, one of the transparent substrates on which the photoconductive layer mainly composed of hydrogenated amorphous silicon is formed has a thermal expansion coefficient of 50 × 10 ⁻⁷ / ° C. or less. preferable. Further, in the spatial light modulator of the present invention, at least a portion of the light-transmitting electrode on one of the light-transmitting substrates on which the photoconductive layer mainly composed of hydrogenated amorphous silicon is in contact with the photoconductive layer is tin oxide. Preferably. The spatial light modulator of the present invention,
Recording can be performed by writing optical information by applying an AC voltage between the two translucent electrodes.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a spatial light modulator according to the present invention will be described in detail with reference to the drawings. FIGS. 1A and 1B show an example of the spatial light modulator of the present invention, wherein FIG. 1A is a plan view, and FIG. 1B is a schematic sectional view taken along the line xx '. In the figure, the spatial light modulator has a light transmitting electrode 20 provided on a light transmitting substrate 10, a photoconductive layer 3 mainly composed of hydrogenated amorphous silicon, and a light reflecting layer 4 such as a dielectric mirror. The light modulating member layer 5 is sandwiched between the light modulating member layer 5 and the light transmitting electrode 21 provided on the light transmitting substrate 11. In the figure, a portion from the light transmitting substrate 10 to the photoconductive layer 3 is a light input portion. FIG. 2 is a schematic cross-sectional view of another example of the spatial light modulator of the present invention, in which a photoconductive layer mainly composed of hydrogenated amorphous silicon includes a first photoconductive layer 30 and a second photoconductive layer. It consists of 31.

In the present invention, the light-transmitting substrate is a plate made of a transparent inorganic material such as glass, quartz, sapphire or the like having a sufficient transmittance for writing light or reading light, and has a coefficient of thermal expansion. Is preferably 50 × 10 ⁻⁷ / ° C. or less.

The light-transmitting electrode provided on the light-transmitting substrate is made of a transparent conductive material such as tin oxide, indium oxide, tin oxide (ITO) doped with indium, zinc oxide, lead oxide, and copper iodide. Used, formed by a method such as vapor deposition, ion plating, sputtering, or A
A metal such as l, Ni, Au, or the like formed thin enough to be translucent by vapor deposition sputtering is used. Among them, tin oxide, indium oxide, and ITO are preferable because they are excellent in both light transmittance and conductivity. In the present invention, it is preferable that at least a portion of the light-transmitting electrode on one of the light-transmitting substrates on which the photoconductive layer is directly formed mainly of hydrogenated amorphous silicon and which is in contact with the photoconductive layer is made of tin oxide. Is done. The film thickness is appropriately set in the range of 0.01 to 0.50 μm according to the required light transmittance and conductivity.

The photoconductive layer is made of at least hydrogenated amorphous silicon, and is formed by a glow discharge method, ECR (Electron Cyclotron).
(resonance) method or the like. At the time of the formation, it is preferable to contain a halogen in addition to an element for terminating a dangling bond, for example, hydrogen or hydrogen.
It is preferably in the range of ４０40 at%. In the present invention, the constituent material of the photoconductive layer is particularly preferably hydrogenated amorphous silicon (a-Si: H). The photoconductive layer preferably contains a group III element or a group V element as an impurity element for controlling conductivity. The amount of addition is determined by the polarity of the voltage applied to the spatial light modulator or the required spectral sensitivity.
It is used in the range of 001 to 100 ppm. The photoconductive layer mainly composed of hydrogenated amorphous silicon has, for the purpose of improving dark resistance, reducing light resistance, improving sensitivity, etc.,
Elements such as nitrogen, carbon, and oxygen can be added. In this case, it is contained in the range of 1 to 1000 ppm. The photoconductive layer can also contain germanium and / or tin. The thickness of the photoconductive layer is 1 to
A range of 100 μm is preferred, and a range of 2 to 60 μm is particularly suitable. The photoconductive layer may be composed of two layers, a charge generation layer and a charge transport layer.

As the light modulating member layer, a liquid crystal film can be used. As the liquid crystal film, a polymer-liquid crystal composite film in which liquid crystal is dispersed in liquid crystal or a polymer film, or a polymer liquid crystal film in which liquid crystal is polymerized in a polymer film is used. As the liquid crystal, various liquid crystals used as general display materials such as a nematic type, a cholesteric type, a smectic type and a ferroelectric type can be used. Specifically, biphenyl, phenylbenzoate, cyclohexylbenzene, azoxybenzene, azobenzene, azomethine, terphenyl, biphenylbenzoate, cyclohexylbiphenyl, phenylpyrimidine, cyclohexylpyrimidine, cholesterol, etc. Of various liquid crystal compounds. These liquid crystals need not have a single configuration, but may be composed of a plurality of components. In the case of a polymer-liquid crystal composite film, a polymer material such as a polyester resin, a polycarbonate resin, a polyamide resin, and an acrylic resin is used as the polymer film for dispersing liquid crystal. Among these polymer materials, a smectic type or A polymer-liquid crystal composite film can be obtained by dispersing a liquid crystal such as a nematic type.
The thickness of these liquid crystal layers is preferably in the range of 1 to 100 μm.

In the spatial light modulator of the present invention, a light reflection layer may be provided between the photoconductive layer and the light modulation member layer. As the light reflection layer, a dielectric multilayer film can be used.
As the dielectric, Si, Ge high refractive index material or Si
A layer in which O ₂ , TiO ₂ , ZnO _2, etc. are repeatedly laminated alternately is used. A-Si by plasma CVD:
H and a-SiGe: H, a-SiCx: H, a-SiN
x: H, a-SiOx: H or the like can also be used.

In the spatial light modulator of the present invention, a light absorbing layer may be provided between the photoconductive layer and the light modulating member layer. The light absorbing layer is coated with a coating liquid in which a light absorbing pigment such as carbon black is dispersed in a photopolymerizable resin such as an acrylic resin, a polyimide or a polyamide, or a thermosetting resin such as an epoxy resin or a melamine resin. After that, it can be formed by light irradiation and / or heating. In the light absorbing layer, the light transmittance and the specific resistance change depending on the content of the light absorbing pigment. In the case of the present invention, at the input light wavelength used, the light transmittance is 0.5% or less and the specific resistance is 10%. ⁶ Ω
cm or more. Also, an amorphous carbon film formed by using glow discharge can be used. The thickness of these absorbing layers is adjusted depending on the wavelength used, but is generally preferably in the range of 0.1 to 100 μm. When the light reflecting layer is provided, a light absorbing layer is preferably provided between the reflecting layer and the photoconductive layer. Further, an antireflection layer may be provided on the surface of the light-transmitting substrate which is not in contact with the light-transmitting electrode, for the purpose of preventing reflection on the substrate surface. The anti-reflection layer can be formed by evaporating MgF ₂ or the like.

Next, a description will be given of a deposition preventing member used for forming a photoconductive layer mainly of hydrogenated amorphous silicon when manufacturing the spatial light modulator of the present invention. FIGS. 3A and 3B are diagrams illustrating a case where a film-preventing member is used in manufacturing the spatial light modulator of the present invention. FIG. FIG. 3B is a plan view of the state in which the prevention members are stacked, and FIG. A light-transmitting electrode (not shown) is formed on the light-transmitting substrate 10, and a deposition preventing member 71 covering the entire periphery of the end of the light-transmitting substrate 10 is provided on the substrate holding member 70. . As the deposition prevention member 71, a metal or ceramic that does not deform at the temperature at the time of forming the photoconductive layer and is hardly magnetized can be used. From the viewpoint of workability and durability during repeated use,
In the present invention, those made of SUS304 or SUS316 are preferably used.

FIGS. 3 (c), 3 (d) and 3 (e)
FIG. 4 is a view for explaining another specific example in the case where a film-forming preventing member is used in the present invention, and is a schematic cross-sectional view when a film-forming preventing member is provided. In order to cover the entire periphery of the end portion of the translucent substrate 10 more reliably, in FIG.
2 is used.
3D, a substrate holding spring 74 is used, and FIG.
In (e), a wedge-shaped substrate holding plate 75 is also used.

The range of the end portion of the light-transmitting substrate which covers the entire periphery with the above-mentioned deposition preventing member is to obtain a portion where the photoconductive layer is not sufficiently formed even when the end portion of the light-transmitting substrate is chamfered. , At least about 1.0 mm from the end is required,
In order to obtain an effective area in which the photoconductive layer is deposited on the light-transmitting substrate, the thickness is preferably at most about 5.0 mm.

Next, a case where optical information is written using the spatial light modulator of the present invention to reproduce an image will be described. When operating the spatial light modulator, an AC voltage is applied between two opposing light-transmitting elements. When writing light is incident from the photoconductive layer side in this state, the impedance of the photoconductive layer mainly composed of hydrogenated amorphous silicon decreases in the exposed area, and the supplied AC voltage changes the liquid crystal of the light modulating member layer. To change the orientation of the liquid crystal molecules. On the other hand, the impedance of the hydrogenated amorphous silicon does not change in a region where light is not applied, and the liquid crystal molecules of the liquid crystal layer maintain the initial alignment state. as a result,
An image corresponding to the incident light is formed on the liquid crystal layer.

FIG. 4 is a diagram for explaining the above-mentioned writing and image reproduction. In the spatial light modulator of the present invention, the photoconductive layer 3, the light reflecting layer 4, and the light modulating member layer 5 are arranged to face each other. It has a structure sandwiched between light-transmitting electrodes 20 and 21 provided on the light-transmitting substrates 10 and 11, respectively. Optical writing is performed between the translucent electrodes 20 and 21.
A predetermined AC voltage is applied from the AC power supply 9 and an optical signal having an arbitrary spatial pattern is written from the left side of FIG.
This is performed by inputting as 1. In the case where reproduction is performed on the written spatial light modulation element, a state in which a predetermined AC voltage is applied between both translucent electrodes,
The reading light 92 is incident from the right side of FIG.
Can be read out by a method such as projecting the light 93 reflected on the screen onto a screen.

[0023]

EXAMPLES Examples 1 to 6 and Comparative Examples 1 to 6 of the present invention
Table 1 and Table 2 collectively show the manufacturing conditions of the light-transmitting substrate, the light-transmitting electrode, and the photoconductive layer, the appearance of the light input portion, the dark resistance, and the light resistance ratio for the spatial light modulator of No. 5. “Alkali” in the column of the material of the light-transmitting substrate in Table 1 is generally called soda-lime glass, and is # 0050 glass manufactured by Matsunami Glass Co., Ltd. Similarly, “alkali-free” is a borosilicate glass generally called heat-resistant glass, and is a Tempax glass manufactured by Schott. The coefficient of thermal expansion (unit: × 10 ^-7 / ° C) of the translucent substrate is 87 for alkali,
No alkali is 32 and quartz is 5. In addition, in the column of the appearance properties of the light input portion in Table 2, the presence or absence of peeling of the photoconductive layer mainly composed of hydrogenated amorphous silicon (when peeled, when peeled) and the light-transmitting substrate of 50 mm × 50 mm square are shown. Shows the amount of warpage at a central portion of 30 mm.

First, a method of manufacturing a spatial light modulator according to the present invention will be described with reference to FIG. Example 1 Alkali-free glass (Tempax 50 × 50 × 3.3 mm thick) was used as the light-transmitting substrate 10, and an ITO film was first formed on the surface thereof to a thickness of 0.2 μm by vapor deposition. Then, a SnO ₂ film was formed so as to have a thickness of 0.05 μm, and the translucent electrode 20 was manufactured. The substrate on which the translucent electrode was formed was washed with pure water and warm pure water and a surfactant using ultrasonic vibration and dried. The translucent electrode 20 is fixed in the reaction vessel so as to expose the surface using the film-preventing member 71 shown in FIG. 3B, and after exhausting the inside of the reaction vessel, a mixture of silane gas, hydrogen gas and diborane gas is mixed. Gas was introduced. The mixed gas was decomposed by glow discharge to form a photoconductive layer 3 on the translucent electrode 20 to produce a light input section. In addition, the range of the entire periphery of the substrate end covered with the film deposition preventing member is 5 mm from the end,
The conditions for forming the photoconductive layer 3 were as follows. 100% silane gas: 200 cm ³ / min of 100% hydrogen gas flow rate: 150 cm ³ / min of hydrogen diluted diborane gas (1 ppm) flow: 50 cm ³ /
Min Reaction vessel internal pressure: 133.3 Pa Substrate heating temperature: 250 ° C. Discharge power density: 0.06 W / cm ³ Discharge time: 180 minutes

After the film was formed, the inside of the reaction vessel was cooled and returned to the atmospheric pressure, and the light input portion was taken out. As a result, there was no deposition of the photoconductive layer 3 on the end of the substrate, and a stable film without peeling over time was obtained. Film thickness 10
A μm photoconductive layer 3 was formed. An Au electrode was vapor-deposited on another light input part produced at the same time, and the resistance was measured. The resistance was 1 × 10 ¹¹ Ωcm in the dark and 8 × 10 ⁸ Ωcm in the light.
Was confirmed.

On the photoconductive layer 3 obtained as described above,
A carbon-based paint in which carbon black is dispersed in an acrylic resin is applied using a spinner, photopolymerized by exposure, and then sintered at 220 ° C. for 1 hour to obtain a film thickness of about 1 μm and a specific resistance of 10 μm. ^{At 10} Ωcm, a light absorbing portion having a transmittance in the visible region of about 0.1% was formed. Further, on the formed light absorbing portion, crystalline Si and SiO ₂ films were alternately formed as light reflecting portions by 10 nm by electron beam evaporation.
A light reflecting layer 4 was formed by forming a multilayer film in which five layers were stacked. Further, a liquid crystal layer made of a scattering type liquid crystal composite film was formed as the light modulation member layer 5. That is, a monomer obtained by mixing n-butyl acrylate and 1,6-hexylene diacrylate in a ratio of 3: 1 and a nematic liquid crystal (E7, Mer
ck) was applied at a ratio of 15:85, and 2% by weight of an ultraviolet polymerization initiator (Darocur 1173, manufactured by Ciba Geigy) was added. Thereafter, ultraviolet light irradiation was performed to form a scattering-type liquid crystal composite film having a thickness of 10 μm.

On the light modulation member layer 5 thus formed, an ITO film having a thickness of 0.1 μm was formed on the light transmitting substrate 11 by vapor deposition to form a second glass substrate which was used as the light transmitting electrode 21. Then, the light modulating member layer 5 and the translucent electrode 21 were overlapped with each other to obtain a spatial light modulating element.

Between the opposing light transmitting electrodes 20 and 21 of the optical writing type spatial light modulator having the above structure, 30
An image was written under the conditions of a wavelength of 660 nm and an exposure of 0.5 μJ / cm ² by applying an alternating voltage of 1 KHz at V. When an image was read out using white light from a halogen lamp, an image having a resolution of 50 lp / mm and a good contrast could be obtained.

Example 2 A substrate pressing plate 73 as shown in FIG. Further, a light input portion was produced in the same manner as in Example 1, except that the covering area around the entire edge of the substrate was 2 mm from the edge, and the discharge time was 450 minutes, and a spatial light modulator was obtained in the same manner. Was. In this case, there was no deposition of the photoconductive layer 3 over the entire periphery of the substrate end portion of the light input portion, and the photoconductive layer 3 having a stable thickness of 25 μm, which did not peel off with time, was obtained. When an Au electrode was vapor-deposited on another light input part produced at the same time and the resistance was measured, the resistance was 1 × 10 ¹² Ωcm in the dark and 3 × 1 in the light.
It is a 0 ⁸ Ωcm has been confirmed.

An AC voltage of 30 V and 1 KHz is applied between the opposing light-transmitting electrodes of the obtained light-writing type spatial light modulator, at a wavelength of 660 nm and an exposure of 0.6 μJ / cm ^2.
Image writing was performed under the following conditions. When the image was read out using white light from a halogen lamp, the resolution was 50
lp / mm and an image with good contrast could be obtained.

Example 3 As a film deposition preventing member, a substrate pressing spring 74 as shown in FIG. Further, the coating range of the entire periphery of the end of the substrate was 1 mm from the end. An optical input unit was manufactured in the same manner as in Example 1 except that the discharge time was 360 minutes, and a spatial light modulator was obtained in the same manner. In this case, there was no deposition of the photoconductive layer 3 over the entire periphery of the substrate end portion of the light input portion, and the photoconductive layer 3 having a stable film thickness of 20 μm which did not peel off with time was obtained.
When an Au electrode was deposited on another light input part produced at the same time and the resistance was measured, it was 3 × 10 ¹² Ωcm in the dark and 1 in the light.
× 10 ⁸ Ωcm was confirmed.

An AC voltage of 30 V and 1 KHz was applied between opposing light-transmitting electrodes of the obtained light-writing type spatial light modulator, at a wavelength of 660 nm and an exposure of 0.5 μJ / cm ^2.
Image writing was performed under the following conditions. When the image was read out using white light from a halogen lamp, the resolution was 50
lp / mm and an image with good contrast could be obtained.

Example 4 A wedge-shaped substrate pressing plate 75 as shown in FIG. In addition, the coating range around the entire edge of the substrate was 3 mm from the edge. An optical input unit was manufactured in the same manner as in Example 1 except that the discharge time was 360 minutes, and a spatial light modulator was obtained in the same manner. In this case, there is no deposition of the photoconductive layer 3 over the entire periphery of the substrate end portion of the light input portion.
As a result, a stable photoconductive layer 3 having a thickness of 20 μm without peeling over time was obtained. When an Au electrode was deposited on another light input part produced at the same time and the resistance was measured, the resistance was 2 × 10 ¹² Ωcm in the dark,
It was confirmed that it was 1 × 10 ⁸ Ωcm at the time of light.

An alternating voltage of 30 V and 1 KHz is applied between the opposing light-transmitting electrodes of the obtained light-writing type spatial light modulator, at a wavelength of 660 nm and an exposure of 0.5 μJ / cm ^2.
Image writing was performed under the following conditions. When the image was read out using white light from a halogen lamp, the resolution was 50
lp / mm and an image with good contrast could be obtained.

Example 5 A quartz (50 × 50 × 3.0 mm) was used as the light-transmitting substrate 10.
An optical input part was produced in the same manner as in Example 2 except that the thickness was used, and a spatial light modulator was obtained in the same manner. in this case,
There is no deposition of the photoconductive layer 3 over the entire periphery of the substrate end of the light input portion, and the photoconductive layer 3 has a stable thickness of 25 μm and does not peel off over time.
was gotten. When an Au electrode was deposited on another light input part produced at the same time and the resistance was measured, the resistance was 2 × 10 ¹² Ωc in the dark.
m and 2 × 10 ⁸ Ωcm at the time of light.

An alternating voltage of 30 V and 1 KHz is applied between the opposing light-transmitting electrodes of the obtained light-writing type spatial light modulator, at a wavelength of 660 nm and an exposure of 0.5 μJ / cm ^2.
Image writing was performed under the following conditions. When the image was read out using white light from a halogen lamp, the resolution was 50
lp / mm and an image with good contrast could be obtained.

Next, a method of manufacturing the spatial light modulator of the present invention in which the photoconductive layer is composed of two layers of hydrogenated amorphous silicon will be described with reference to FIG. 2 as an example. Example 6 A non-alkali glass (Tempax 50 × 50 × 3.3 mm thick) was used as the light-transmitting substrate 10, and a SnO ₂ film was formed to a thickness of 0.3 μm on its surface by a vapor deposition method. The light-transmitting electrode 20 was produced. The substrate on which the translucent electrodes were formed was washed with ultrasonic vibration using pure water, warm pure water and a surfactant, and dried. Using a film-preventing member 72 as shown in FIG. 3 (c) so that the translucent electrode 20 is exposed on the surface in the reaction vessel, and using the substrate pressing plate 73 together, the covering area around the entire edge of the substrate is reduced. It fixed so that it might become 2 mm from an edge part. Next, after exhausting the inside of the reaction vessel, the first
A mixed gas of silane gas, hydrogen gas and diborane gas was introduced for forming the photoconductive layer 30 of FIG. The first photoconductive layer 30 was formed on the translucent electrode 20 by glow discharge decomposition of the mixed gas under the following film forming conditions.

100% silane gas flow rate: 200 cm ³ / min 100% hydrogen gas flow rate: 180 cm ³ / min Hydrogen diluted diborane gas (100 ppm) flow rate: 20 cm
³ / min Internal pressure of reaction vessel: 133.3 Pa Substrate heating temperature: 250 ° C. Discharge power density: 0.06 W / cm ³ Discharge time: 5 minutes

Next, after the inside of the reaction vessel was evacuated once, a mixed gas of silane gas, hydrogen gas and diborane gas was introduced for forming the second photoconductive layer 31. The mixed gas is decomposed by glow discharge under the following film forming conditions, whereby the first gas is decomposed.
A second photoconductive layer 31 was formed on the photoconductive layer 30 of No. 1 to form a light input section.

[0040] 100% silane gas: 200 cm ³ / min of 100% hydrogen gas flow rate: 150 cm ³ / min of hydrogen diluted diborane gas (1 ppm) flow: 50 cm ³ /
Min Reaction vessel internal pressure: 133.3 Pa Substrate heating temperature: 250 ° C. Discharge power density: 0.06 W / cm ³ Discharge time: 360 minutes

After the film formation, the inside of the reaction vessel was cooled and returned to the atmospheric pressure, and the light input section was taken out. As a result, there was no deposition of the photoconductive layers 30 and 31 on the substrate end, and there was no delamination over time. A photoconductive layer 3 having a proper film thickness of 20 μm was obtained. When an Au electrode was vapor-deposited on another light input part produced at the same time and the resistance was measured, the resistance was 5 × 10 ¹² Ωcm in the dark and 2 × 10 ⁸ Ωcm in the light.
Was confirmed.

Using the obtained light input section, a spatial light modulator was manufactured in the same manner as in Example 1. A voltage of 30 V is applied between the opposing translucent electrodes of the obtained optical writing type spatial light modulator.
, An image was written under the conditions of a wavelength of 660 nm and an exposure of 0.4 μJ / cm ² .
When an image was read out using white light from a halogen lamp, an image having a resolution of 50 lp / mm and a good contrast could be obtained.

Comparative Example 1 As the translucent substrate 10, an alkali glass (50 × 50 ×
(2.8 mm thick) and a 0.2 μm thick ITO
A film was formed, and the translucent electrode 20 was manufactured. The substrate shown in FIG. 5 was used as the substrate holding member, and the photoconductive layer 3 was formed in the same manner as in Example 1 except that the discharge time was set to 90 minutes, thereby producing a light input portion. In FIG. 5, (a)
FIG. 2 is a plan view showing a state in which the translucent substrate 10 is placed on the substrate holding member 80, and FIG. 2B is a schematic cross-sectional view taken along line xx ′. When the light input portion was taken out of the reaction vessel, the photoconductive layer 3 started to peel off from the end of the substrate, and almost one day later, the photoconductive layer 3 was peeled off. At the same time, the thickness of the photoconductive layer 3 deposited on the aluminum substrate was 5 μm.

Comparative Example 2 A non-alkali glass (50 × 50) was used as the light-transmitting substrate 10.
× 3.3 mm thick) and a 0.2 μm thick IT
An O film was formed, and the light-transmitting electrode 20 was obtained. As a substrate holding member, a photoconductive layer 3 having a thickness of 5 μm was formed in the same manner as in Example 1, except that the discharge time was 90 minutes, and spatial light modulation was performed in the same manner as in Example 1. An element was manufactured. At the same time, an Au electrode was vapor-deposited on another light input part, and the resistance was measured. As a result, it was confirmed that the resistance was 5 × 10 ⁹ Ωcm in the dark and 9 × 10 ⁶ Ωcm in the light. In FIG. 6, (a) is a plan view of a state in which the translucent substrate 10 is placed on the substrate holding member 80 and fixed by the substrate holding member 81 holding two opposing sides of the substrate, and (b). Is a schematic sectional view taken along line xx '. When writing was performed on this spatial light modulator, the dark resistance was low and the light-to-dark resistance ratio was low, so that a voltage was also applied to the liquid crystal layer in the dark and no operation was performed.

Comparative Example 3 The photoconductive layer 3 was formed in the same manner as in Comparative Example 2 except that the discharge time was changed to 180 minutes. A portion of the photoconductive layer 3 was peeled off. At the same time, the thickness of the photoconductive layer 3 deposited on the aluminum substrate was 10 μm.

Comparative Example 4 As the translucent substrate 10, quartz (50 × 50 × 3.0 mm) was used.
Thickness), except that the thickness was 5 μm.
Was formed, and a light input section was produced. When an Au electrode was vapor-deposited on another light input part produced at the same time and the resistance was measured, the resistance was 8 × 10 ⁹ Ωcm in the dark and 1 × 10 ^{7 in the} light.
Ωcm was confirmed. Using the obtained light input section, a spatial light modulator having a sectional structure shown in FIG. 7 was manufactured.
That is, the upper surface of the light reflection layer 4 formed by filling the light modulation member layer 5 between the spacers 6 shown in FIG.
After a liquid crystal alignment layer (not shown) is provided on the reflective layer 4, a coating liquid containing a mixture of spacer particles and an ultraviolet curable resin is applied to the outer periphery of the liquid crystal alignment layer on the reflective layer 4 except for the liquid crystal injection port. The alignment layers were bonded to face each other, and the resin was cured by irradiating ultraviolet rays to form spacers 6. Then spacer 6
The cavities formed in the above were exhausted, TN liquid crystal was injected from the liquid crystal injection port, and the liquid crystal injection port was sealed. Other symbols are the same as those in FIG. When writing was performed on this spatial light modulator, the contrast was small and it did not operate.

Comparative Example 5 When the photoconductive layer 3 was formed in the same manner as in Comparative Example 4 except that the discharge time was changed to 180 minutes, the photoconductive layer 3 began to peel after the light input portion was taken out of the reaction vessel. Most of the photoconductive layer 3 was peeled off. At the same time, the thickness of the photoconductive layer 3 deposited on the aluminum substrate was 10 μm.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

According to the spatial light modulation element of the present invention, the photoconductive layer mainly composed of hydrogenated amorphous silicon having a thickness capable of obtaining an impedance capable of operating the light modulation member layer satisfactorily has a light transmitting property. Since the photoconductive layer is provided at a portion other than the entire periphery of the edge of the substrate, the photoconductive layer does not peel off, and a high-performance, high-resolution, high-contrast image can be obtained. Further, according to the manufacturing method of the present invention, at the time of forming a photoconductive layer mainly composed of hydrogenated amorphous silicon on the translucent electrode on one translucent substrate,
The light modulating member layer operates well by using a film-preventing member that covers the entire edge of the light-transmitting substrate so that the photoconductive layer is not formed over the entire edge of the light-transmitting substrate. The thickness of the photoconductive layer can be satisfactorily deposited up to a thickness at which the impedance can be obtained, and the photoconductive layer is prevented from peeling, which is considered to be caused by minute scratches or cracks at the upper end of the light-transmitting substrate. The yield of the input section can be improved, and the cost of the element can be reduced.

[Brief description of the drawings]

FIG. 1 shows an example of a spatial light modulator according to the present invention, wherein (a) is a plan view and (b) is a schematic sectional view.

FIG. 2 is a schematic sectional view of another example of the spatial light modulator of the present invention.

FIGS. 3A and 3B are explanatory views illustrating a case where a deposition preventing member is used in manufacturing the spatial light modulator of the present invention, wherein FIG. 3A is a plan view, and FIGS. It is a typical sectional view for explaining an embodiment.

FIG. 4 is an explanatory diagram for explaining a method of performing optical writing and reading using the spatial light modulator of the present invention.

5A and 5B are schematic diagrams illustrating a structure of a substrate holding member used for manufacturing a spatial light modulation element in Comparative Example 1, wherein FIG. 5A is a plan view and FIG. 5B is a schematic cross-sectional view.

6A and 6B are schematic diagrams illustrating a structure of a substrate holding member used for manufacturing a spatial light modulation element in Comparative Example 2, wherein FIG. 6A is a plan view and FIG. 6B is a schematic cross-sectional view.

FIG. 7 is a schematic sectional view of a spatial light modulator of Comparative Example 4.

[Explanation of symbols]

10, 11: translucent substrate, 20, 21: translucent electrode, 3
... Photoconductive layer, 30 ... First photoconductive layer, 31 ... Second photoconductive layer, 4 ... Light reflecting layer, 5 ... Light modulating member layer, 6 ... Spacer, 70 ... Substrate holding member, 71 ... Substrate edge A film-preventing member covering the entire periphery of the portion, 72: a film-preventing member, 73: a substrate pressing plate, 74: a substrate pressing spring, 75: a wedge-shaped substrate pressing plate, 80: a substrate holding member, 81: facing the substrate 9: an AC power supply, 91: writing light, 92: reading light, 93: reflected light.

Claims (2)

[Claims] 1. A pair of opposing light-transmitting substrates, a light-transmitting electrode provided on a surface of each light-transmitting substrate, and hydrogenation provided between the opposing light-transmitting electrodes. In a spatial light modulator having a photoconductive layer mainly composed of amorphous silicon and a light modulating member layer, the photoconductive layer has a thickness of 2 to 60 μm, and a portion excluding the entire periphery of the end portion of the light transmitting substrate. A spatial light modulation device provided in the device. 2. A light-transmitting electrode is formed on the surface of a pair of light-transmitting substrates, and light mainly composed of hydrogenated amorphous silicon is formed on the light-transmitting electrode formed on one of the light-transmitting substrates. Manufacturing of a spatial light modulating element comprising sequentially forming a conductive layer and a light modulating member layer, and overlapping the light modulating member layer so that the light transmitting electrode formed on the surface of the other light transmitting substrate is in contact with the conductive layer. In the method, when a photoconductive layer mainly composed of hydrogenated amorphous silicon is formed on a light-transmitting substrate on which a light-transmitting electrode is formed, film deposition is prevented so as to cover the entire edge of the light-transmitting substrate. A method for manufacturing a spatial light modulator, comprising forming a photoconductive layer having a thickness of 2 to 60 μm with the members stacked.