JPH0521157A - Space light modulating element and optical arithmetic device - Google Patents

Abstract

PURPOSE:To provide an optical arithmetic device of large quenching ratio of modulated light and of excellent arithmetic processes such as optical summation and binarizing function, by constructing a space light modulating element with a phosphor thin film mainly composed of zinc sulfide containing luminous active materials such as Mn or the like and a composite oxide thin film mainly composed of Bi and Si. CONSTITUTION:On an insulating substrate 1 such as glass or the like a transparent electrode consisting of ITO or the like is evaporated, on which a BSO thin film is laminated by sputtering, on which a phosphor thin film of ZnS:Mn is provided with electron beam evaporation method, on which an insulating film 5 of alumina or the like is laminated by sputtering, and at last on which an electrode 6 of aluminum or the like is evaporated and deposited.

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 used for optical digital calculation, optical analog calculation and the like, and more particularly to a spatial light modulator in which a photoconductive layer and a phosphor layer are combined. The present invention also relates to an optical arithmetic device for performing optical neurocomputing such as pattern recognition and associative memory using the spatial light modulator of the present invention.

[0002]

2. Description of the Related Art Spatial light modulators are based on two-dimensional information recorded in advance with respect to image information contained in incident light, and the intensity, polarization angle, phase of original incident light, other incident light or emitted light. A device that modulates spatial image information by controlling, for example, an optical crystal that utilizes the Pockels effect, a liquid crystal that utilizes the anisotropy of the refractive index, etc. Has been.

Bi ₁₂ SiO ₂₀ (hereinafter referred to as "BSO")
Abbreviated. ) Or amorphous Si (a-Si) or the like and a liquid crystal cell are laminated, and the light receiving portion and the spatial light modulating portion are integrated with each other, thereby providing an optical threshold processing function, and the results are A spatial light modulator for output has been proposed (Kuniharu Takizawa et al., Proceedings of the 35th Joint Lecture Meeting of the Japan Society of Applied Physics, Spring 1988 30P-ZF-3, 30P).
-ZF-4). The photoconductive layer of this device has a B of about 900 ° C.
A BSO single crystal obtained by growing a BSO single crystal from an SO melt by the Czochralski method, cutting this to an arbitrary thickness, and processing it by polishing to a thickness of about 500 μm is used.

Further, as a spatial light modulator in which a light receiving part and a light emitting part are laminated, a device using amorphous SiC and an electroluminescence (hereinafter referred to as “EL”) layer has been proposed.

Next, as a conventional optical arithmetic device, a plurality of spatial light modulators are superposed, and further, a light receiving element array which receives the transmitted light is aligned and the product calculation of light is performed by parallel processing. Proposed. This has functions such as association, fuzzy processing, and program-less, which were difficult to realize with conventional von Neumann computers, and is called a neurocomputer modeled on the neural network of living organisms. It In particular, the optical neurocomputer does not require complicated wiring such as LSI, because multiple connections between neurons corresponding to synapses are easily realized by optical connection, and electric signals are used as an information medium. It has excellent features not found in. Therefore, various configurations have been conventionally proposed for optical neurocomputers capable of high-speed information processing.

Among them, one of the arithmetic functions which can be said to be the basis of neuro-computing is to perform summation on a large number of input information coming into a neuron and compare the arithmetic result with a predetermined reference value. There is a threshold processing function of binarizing or multi-valued. The realization of a spatial light modulator having such a calculation function is the most important for making the neural network into hardware.

[0007]

However, in the conventional spatial light modulator using the photoconductive layer and the liquid crystal, the modulated light can enter only from the liquid crystal surface, and the light modulator layer is limited to the reflective type. There is a problem that the optical system becomes complicated to construct the optical operation device having the hierarchical structure.

Further, since the light modulation characteristic of the liquid crystal with respect to the applied voltage is generally gradual, there is a problem that it is difficult to perform accurate threshold processing. FIG. 6 is a graph showing the input / output characteristics of a spatial light modulation element in which a photoconductive layer and a light modulation layer are combined using various materials. The conventional spatial light modulator is
BSO + liquid crystal, a-Si + liquid crystal, a-S, respectively
In contrast to the i + EL combination, the spatial light modulator of the present invention is a BSO + EL combination. For ease of comparison, the horizontal axis is plotted in linear arbitrary units and the vertical axis is plotted in logarithmic arbitrary units so that the input and output characteristics have the same threshold value. Looking at FIG. 6, the graph of, shows the input / output characteristics having a gradual slope in the vicinity of the horizontal axis scales 40 to 50, and the extinction ratio of the light output is limited to about 10 to the power of 2 digits. Be understood.

It is also known that the thinner the thickness of the photoconductive layer of the spatial light modulator, the more the image bleeding and blurring due to scattering of input light and flare are reduced, and the spatial resolution of the device is improved. However, the conventional spatial light modulator uses B as the photoconductive layer.
Since the SO single crystal is used, there is a problem in manufacturing the single crystal thin film that it can be processed only to a thickness of about 200 μm in terms of mechanical strength. Therefore, the spatial resolution of the device could be achieved only up to about 20 [lp / mm].

On the other hand, in a light emitting type spatial light modulator using a photoconductive layer and an EL layer, it is necessary to apply a high electric field of 10 ⁶ [V / cm] to obtain EL light emission. In order to efficiently apply an electric field to the layer, a material having a high breakdown voltage and a high relative dielectric constant is required for the photoconductive layer, and there is a problem that the conventional amorphous Si-based material is insufficient. In addition, since the amorphous Si-based material is insufficient in electrical insulation, it is necessary to provide another insulating layer, and an additional forming step is added to increase the number of steps, which leads to deterioration of manufacturing yield and increase in cost. There was a problem.

Next, in the conventional spatial light modulator,
When the input light is incident on the photoconductive layer, there is a problem that arithmetic processing such as light addition cannot be performed on the light incident on a predetermined area.

In order to perform light calculation processing, for example, it is assumed that a conductive electrode having a shape corresponding to a region to be summed is provided between the photoconductive layer and the liquid crystal layer. In the light modulation element, even if the light is accurately summed in consideration of the incident light intensity dependency of the photoconductive layer, there is a problem that the threshold processing accuracy is low due to the variation in the nonlinear characteristic of the liquid crystal. It was

In order to solve the above-mentioned problems, the present invention provides a spatial light modulation element capable of performing highly accurate and stable threshold value processing, and at the same time, an optical calculation with high calculation accuracy using this spatial light modulation element. The purpose is to provide a device.

[0014]

In order to solve the above-mentioned problems, the spatial light modulator of the present invention has a composite oxide thin film containing at least bismuth and silicon as main components on at least one surface of a phosphor thin film. It is characterized in that it is provided.

Further, in the spatial light modulator of the present invention, an insulator thin film is provided on at least one surface of the phosphor thin film, and at least one island-shaped conductive film is provided on the surface of the insulator thin film. Alternatively, a complex oxide thin film containing at least bismuth and silicon as main components is provided on the surface of the conductive film.

In the above structure, it is preferable that the phosphor thin film is a light emitting layer whose main component is zinc sulfide containing a light emitting active substance. Further, in the above structure, the luminescent active material is Mn, Cu, Ag, Al, Tb, Dy, Er, P.
It is preferably at least one selected from the group consisting of r, Sm, Ho, Tm and their halides.

Further, in the above structure, the molecular ratio of silicon oxide in the complex oxide thin film is preferably in the range of 4% to 20%.

In the optical arithmetic unit of the present invention, an insulator thin film is provided on at least one surface of the phosphor thin film, and at least one island-shaped conductive film is provided on the surface of the insulator thin film. At least a spatial light modulator having a complex oxide thin film containing at least bismuth and silicon as main components on the surface of the conductive film, an optical mask, and a two-dimensional lens array.

[0019]

According to the above structure, since the composite oxide thin film containing bismuth and silicon as the main components is used as the photoconductive layer of the spatial light modulator, the high resistance and high insulation of the composite oxide are achieved. , A high electric field can be applied to the phosphor thin film such as the EL layer. Therefore, it is not necessary to newly form an insulating layer for maintaining electrical insulation, and the element structure can be simplified. Further, the relative permittivity of the composite oxide containing bismuth and silicon as main components is 50.
As described above, since the relative dielectric constant becomes larger than that of amorphous Si, when a voltage is applied by laminating the photoconductive layer and the phosphor thin film layer, most of the voltage is proportionally distributed by the relative dielectric constants of both layers. It is distributed to the phosphor thin film layer, and it becomes easy to apply a high electric field to the phosphor.

Also, due to the high resistance and high relative permittivity of the complex oxide containing bismuth and silicon as the main components, sufficient spatial modulation performance can be obtained even if the photoconductive layer is made thin, for example, about 2 μm. It can be maintained, and the thin photoconductive layer reduces blurring and blurring of the input image.
Spatial resolution is improved.

Further, since the phosphor thin film is a light emitting layer mainly containing zinc sulfide containing a light emitting active substance,
Since the threshold characteristic of light emission is steep, the threshold processing of the spatial light modulator is stable and highly accurate. Referring to FIG. 6, in comparison with the graph of, which is the input / output characteristic of the conventional spatial light modulator, the graph of the present invention shows that the horizontal scale 40
It is understood that it exhibits an input / output characteristic that sharply rises in the vicinity, and has an extinction ratio of light output of 10 to the power of 3 or more.

The luminescent active material is Mn, Cu, A.
g, Al, Tb, Dy, Er, Pr, Sm, Ho, Tm
And, by being at least one selected from the group consisting of these halides, the emission intensity of EL can be increased, or a desired emission spectrum can be arbitrarily selected.

Further, since the molecular ratio of silicon oxide in the composite oxide thin film is in the range of 4% to 20%, a spatial light modulator having a large modulated light extinction ratio (ON / OFF ratio) can be obtained. You can

Further, an insulator thin film is provided on at least one surface of the phosphor thin film, at least one island-shaped conductive film is provided on the surface of the insulator thin film, and at least bismuth is provided on the surface of the insulator thin film or the conductive film. By providing a composite oxide thin film containing silicon and silicon as the main components, when the input light is incident on the photoconductive layer made of the composite oxide thin film, the integral action of the input light on the region where the island-shaped conductive film is formed , And it becomes possible to perform light addition processing. Therefore, a desired integration region can be set by forming the island-shaped conductive film into a desired shape. Then, the integrated value of the light summing process becomes the input value of the threshold value process, and since the phosphor thin film of zinc sulfide or the like has abrupt EL emission characteristics, highly accurate and stable threshold value process can be performed. .

According to the configuration of the optical operation device of the present invention, it is possible to easily realize the hierarchical structure of the optical operation device with an optical system. In particular, it is possible to provide a novel optical arithmetic device having a threshold processing function necessary for neurocomputing.

[0026]

Embodiments of the present invention will be described in detail below with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view of an embodiment of the spatial light modulator of the present invention. A transparent electrode 4 made of ITO or the like is formed on the insulating substrate 3 made of glass or the like through which light is transmitted so as to have a film thickness of about 200 nm by an electron beam evaporation method or the like. Next, a metal target in which bismuth and silicon are arranged in an appropriate area ratio is sputtered in argon gas and oxygen gas to form the BSO thin film 5 with a film thickness of about 500 nm. At this time, the substrate temperature is set to 400 ° C. or higher, or 400 ° C. in an oxygen atmosphere in a later process.
By annealing at the above temperature, the crystallinity increases and the film functions as a photoconductive layer.

Next, a phosphor thin film 6 of ZnS: Mn is formed on this by a method such as electron beam evaporation so as to have a film thickness of about 200 nm. Further, an insulating film 7 made of alumina or the like is formed thereon by sputtering or the like so as to have a film thickness of about 500 nm.

Finally, the electrode 8 made of aluminum or the like is formed to have a film thickness of about 200 nm by a vacuum vapor deposition method or the like.
Note that FIG. 2 shows an example of a plan view of the electrode 8. 2 in FIG.
Although a × 2 matrix electrode is shown, an n × m matrix electrode (n and m are natural numbers) can be similarly formed. In this way, the spatial light modulator 1 of the present invention can be obtained.

The operation of the obtained spatial light modulator 1 will be described below. An AC voltage of 5 kHz is applied between the transparent electrode 4 and the electrode 8 by an AC power supply 9. Since the BSO thin film 5 which is a photoconductive layer has a high resistance before light irradiation, most of the voltage is applied to the BSO thin film 5 and the electric field strength in the phosphor thin film 6 does not become so high. Does not emit light. Here, when the optical input 10 having a sufficient intensity is incident on the BSO thin film 5, the electrical resistance of the BSO thin film 5 is lowered by the generation of photocarriers, and most of the voltage is applied to the phosphor thin film 6. Therefore, EL light emission occurs in a region where an electric field is applied exceeding the light emission threshold, and output light is obtained. Therefore, in the light input image information, a space having a binarizing function that outputs light to a portion where the input light intensity is equal to or higher than a predetermined reference value and does not output light to a portion that is lower than the predetermined reference value. The light modulation element 1 is obtained.

Next, since the spatial light modulator 1 shown in FIG. 1 is a reflective element in which output light is emitted to the input light side through the BSO thin film 3, the sensitivity wavelength of the photoconductive layer and the phosphor thin film. The relationship with the emission wavelength of is important.

The photoconductive characteristics of the BSO thin film 5 are shown in FIG.
It has the wavelength dependency of light as shown in. For example, when the phosphor thin film 6 is ZnS: Mn, as shown in FIG.
While an emission spectrum having a peak at 50 nm can be obtained, the photoconductive characteristics of the BSO thin film 5 are hardly affected, so that the BSO thin film 5 operates faithfully with respect to the optical input 10.

Further, since the BSO thin film 5 has a high insulating property and a large dielectric constant, the device reliability is high and a voltage can be efficiently applied to the phosphor thin film 6. By using a transparent electrode such as ITO as the electrode 8 of the spatial light modulator shown in FIG. 1, it is possible to construct a transmissive modulator which takes out output light from the side opposite to the input light side. Can be used to construct a hierarchical optical operation device. Although only one BSO thin film 5 is formed in this embodiment, it is also preferable to provide two layers so as to sandwich the phosphor thin film 6 therebetween. Also,
It is also preferable to form another insulating layer between the phosphor thin film 6 and the BSO thin film 5.

In addition to Mn as the luminescent active substance, Cu, A
g, Al, Tb, Dy, Er, Pr, Sm, Ho, Tm
Also, by using at least one selected from the group consisting of these halides, it is possible to configure a spatial light modulator that outputs a desired emission spectrum.

FIG. 3 is a graph showing the ratio of the photoconductivity and the dark conductivity of the BSO thin film 3 when the molecular ratio of silicon oxide is changed. From this graph, the molecular ratio of silicon oxide in the BSO composite oxide thin film is 4% to 2%.
It is understood that when the range is 0%, the ON / OFF ratio becomes 10 times or more. Therefore, in order to obtain a spatial light modulator having a large modulation extinction ratio, it is preferable to form a complex oxide thin film having a molecular ratio of silicon oxide in the range of 4% to 20%.

(Embodiment 2) FIG. 4 is a sectional view of another embodiment of the spatial light modulator of the present invention. A first transparent electrode 4 made of ITO or the like is formed on the insulating substrate 3 made of glass or the like through which light is transmitted so as to have a film thickness of about 200 nm by an electron beam evaporation method or the like. Next, a metal target in which bismuth and silicon are arranged in an appropriate area ratio is sputtered in argon gas and oxygen gas to form the BSO thin film 5 with a film thickness of about 500 nm. At this time, if the substrate temperature is set to 400 ° C. or higher, or annealing is performed at a temperature of 400 ° C. or higher in an oxygen atmosphere in a later step, the crystallinity is increased and the layer functions as a photoconductive layer.

Next, a conductive film 13 of aluminum or the like is formed on top of this by 2
It is formed by a vacuum deposition method or the like through a metal mask having a predetermined shape so as to have a film thickness of about 00 nm. In addition,
FIG. 5 shows an example of a plan view of the conductive film 13. 2 × in FIG.
Although two matrix electrodes are shown, an n × m matrix electrode (n and m are natural numbers) can be similarly formed.

Further, a first insulating film 14 made of alumina or the like is formed thereon by sputtering or the like so as to have a film thickness of about 500 nm. Then, a ZnS: Mn phosphor thin film 6 is formed thereon by electron beam evaporation or the like so as to have a film thickness of about 200 nm.

Further, a second insulating film 7 made of alumina or the like is formed thereon by a sputtering method or the like so as to have a film thickness of about 500 nm. Finally, the second transparent electrode 15 such as ITO is formed by vacuum vapor deposition or the like so as to have a film thickness of about 200 nm, and the spatial light modulator is completed.

The operation of the obtained spatial light modulator will be described below. An AC voltage of 5 kHz is applied from the AC power supply 9 between the first transparent electrode 4 and the second transparent electrode 15.
Since the BSO thin film 5 which is a photoconductive layer has a high resistance before light irradiation, most of the voltage is applied to the BSO thin film 5 and the electric field strength in the phosphor thin film 6 does not become so high. Does not emit light. Here, when the optical input 10 having a sufficient intensity is incident on the BSO thin film 5, the electrical resistance of the BSO thin film 5 is lowered according to the light intensity due to the generation of photocarriers, and the potential of the conductive film 13 is changed. The voltage applied to the upper phosphor thin film 6 changes. Therefore, EL light emission occurs in a region where an electric field is applied exceeding the light emission threshold, and output light is obtained. Therefore, of the light input image information, the island-shaped conductive film 13
When the total amount of light input in the area where the light emitting diode is formed is equal to or larger than a predetermined reference value, the phosphor corresponding to the area emits EL to emit light. In this way, the light summing process and the two
A spatial light modulator having a binarizing function can be obtained.

The spatial light modulator shown in FIG. 4 has an optical output 11
Is a transmissive element that is taken out on the opposite side of the BSO thin film 5, but if a transparent electrode such as ITO is used as the conductive film 13, it can be configured as a reflective element that takes out the light output from the same side as the light input. . The characteristics of BSO thin film due to its wavelength dependence of photoconductivity, high insulation, and large dielectric constant are as follows.
This is the same as the spatial light modulator according to the first embodiment.

Next, an embodiment of the optical arithmetic unit of the present invention will be described. (Embodiment 3) Based on a hierarchical neural network model as shown in FIG. 9, an optical arithmetic unit 21 was constructed using the spatial light modulator described in Embodiment 2. FIG. 10 is a schematic perspective view of an embodiment of the optical arithmetic unit. For example, the input character 20 such as the character “A” is imaged on the first optical mask 23 by the first lens array 22 having a 4 × 4 matrix arrangement to obtain a multiple image having a 4 × 4 matrix arrangement. . The input character 20 and the first lens array 22 are
It corresponds to the nerve cells in the input layer (in this case, the number of nerve cells is 16) in the neural network model, and the first optical mask 23 corresponds to the synapse between the input layer and the intermediate layer.

Optical masks 23, 26 corresponding to synapses
A liquid crystal whose light transmission amount changes depending on an electric field may be used, or a photochromic element whose light transmission amount changes depending on a light irradiation amount may be used. Also, in the case of a neural network circuit that does not perform learning, a fixed mask that is non-rewritable and has silver salt or dye fixed, as an optical mask,
Alternatively, a fixed mask formed by vapor deposition of metal is used. In this case, the processing content of the fixed mask includes the synapse value obtained by learning by computer simulation.

The transmitted light of the first optical mask 23 is incident on the first spatial light modulating element 24 in which the conductive film 13 is formed in a 4 × 4 matrix in the spatial light modulating element of the second embodiment. The first spatial light modulator 24 corresponds to a nerve cell in the intermediate layer (in this case, the number of nerve cells is 16) in the neural network model, performs optical summation on each conductive film, and binarizes it. It is processed and output as light.

The output light from the first spatial light modulator 24 is expanded into a multiple image by the second lens array 25 of 4 × 4 matrix, and the second optical mask corresponding to the synapse between the intermediate layer and the output layer. 26 (16 × 16 matrix). The transmitted light of the second optical mask 26 is, for example, a second 4 × 4 matrix composed of a photoconductive layer (having sensitivity to the wavelength of the output light of the first spatial light modulator 24) and a reflective liquid crystal layer. Is incident on the spatial light modulator 27. The second spatial light modulator 27 corresponds to the nerve cells in the output layer (in this case, the number of nerve cells is 16). In this way, the output light is obtained from the second spatial light modulator 27 as the light calculation result. The second spatial light modulator 27 also performs optical summation and binarization processing, and outputs light. Note that FIG.
FIG. 11 shows a cross-sectional view of an example of the second spatial light modulation element 27 formed of a combination of a 4 × 4 matrix of a photoconductive layer and a reflective liquid crystal layer, and FIG. 11b shows an example of a plan view of the electrode 33.

The signal from the second spatial light modulator 27 is calculated by an electronic computer for the correction amount of the synapse by the feedback type supervised learning method (for example, error back-propagation learning method), and the first optical The mask 23 and the second optical mask 26 were learned.

The optical arithmetic unit 21 of this embodiment has an input layer of 1
This corresponds to the construction of a neural network composed of 6 neurons, 16 intermediate layers and 16 output layers.

When the input character is recognized using this optical arithmetic unit 21, a recognition rate of almost 100% is obtained,
The degree of convergence of learning is also 5 to 10 times faster. As described above, by using the optical arithmetic unit of the present invention, it becomes possible to easily construct a hierarchical neural network.

[0048]

As described above in detail, according to the spatial light modulator of the present invention, due to the high resistance, high insulation and high dielectric constant of the complex oxide thin film containing bismuth and silicon as the main components, A high electric field can be applied to the phosphor thin film such as the EL layer, and the light modulation efficiency can be improved. Further, since the molecular ratio of silicon oxide in the composite oxide thin film is in the range of 4% to 20%, the modulated light extinction ratio (ON / ON
The OFF ratio) is increased, and the light utilization efficiency is improved.

Further, by forming the photoconductive layer thinly, the spatial resolution of the element is improved, and it is possible to perform a faithful and highly accurate image calculation process for the input image. Also,
By providing at least one island-shaped conductive film on the surface of the insulator thin film provided on at least one surface of the phosphor thin film, the integrated action of the input light on the region where the island-shaped conductive film is formed is shown. Since it is possible to perform the summation processing of, the desired integration area can be set, and the degree of freedom in setting the spatial area to be the image calculation target increases.

Further, since the phosphor thin film is a light emitting layer containing zinc sulfide containing a light emitting active substance as a main component, the light modulating layer has abrupt threshold characteristics, and stable and accurate threshold processing is possible. Becomes Further, by selecting from the above-mentioned group as the luminescent active substance, the luminescence intensity of EL becomes large and efficient calculation processing becomes possible.
By arbitrarily selecting a desired emission spectrum, when a plurality of spatial light modulators are used, the light separation characteristic between the respective devices is improved, and it becomes easy to construct a hierarchical neural network. Further, according to the optical arithmetic device of the present invention, the hierarchical structure of the optical arithmetic device can be easily realized by a simple optical system, and the optical summing and threshold processing functions required for neurocomputing are provided. Can be done at high speed.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a spatial light modulator of the present invention.

FIG. 2 is an example of a plan view of an electrode 8 shown in FIG.

FIG. 3 is a graph showing the ratio of photoconductivity to dark conductivity when the molecular ratio of silicon oxide is changed in the BSO thin film of the spatial light modulator of the present invention.

FIG. 4 is a cross-sectional view of another embodiment of the spatial light modulator of the present invention.

5 is an example of a plan view of a conductive film 13 shown in FIG.

FIG. 6 is a graph showing input / output characteristics of a spatial light modulation element in which a photoconductive layer and a light modulation layer are combined using various materials.

FIG. 7 is a graph showing wavelength dependence of photoconductivity of a BSO thin film.

FIG. 8 is a graph showing an emission spectrum of ZnS: Mn.

FIG. 9 is an explanatory diagram of a neural network model.

FIG. 10 is a schematic perspective view of an embodiment of the optical arithmetic unit of the present invention.

FIG. 11a is a 4 × 4 photoconductive layer and a reflective liquid crystal layer.
FIG. 11B is a cross-sectional view of an example of the second spatial light modulator 27 formed of a combination of matrices, and FIG. 11B is an example of a plan view of the electrode 33.

[Explanation of symbols]

1 Spatial light modulator 3 Insulating substrate 4 transparent electrodes 5 BSO thin film 6 Phosphor thin film 7 Insulating film 8 electrodes 9 AC power supply 10 optical input 11 optical output 13 Conductive film 14 Insulating film 15 Transparent electrode 20 input characters 21 Optical computing device 22 First lens array 23 First optical mask 24 First spatial light modulator 25 Second lens array 26 Second optical mask 27 Second spatial light modulator 30, 38 glass substrate 31, 37 ITO transparent electrode 32 a-Si: H photoconductive layer 33 Al electrode 34, 36 Alignment film 35 Ferroelectric liquid crystal

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Michihiro Miyauchi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Akio Takimoto             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Kuni Ogawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd.

Claims (6)

[Claims] 1. A spatial light modulator comprising a phosphor thin film and a composite oxide thin film containing at least bismuth and silicon as main components provided on at least one surface of the phosphor thin film. 2. An insulator thin film is provided on at least one surface of a phosphor thin film, at least one island-shaped conductive film is provided on the surface of the insulator thin film, and at least bismuth is provided on the surface of the insulator thin film or the conductive film. A spatial light modulator comprising: a composite oxide thin film containing silicon and silicon as main components. 3. The spatial light modulator according to claim 1, wherein the phosphor thin film is a light emitting layer whose main component is zinc sulfide containing a light emitting active substance. 4. The luminescent active material is Mn, Cu, Ag, A
The spatial light modulator according to claim 3, wherein the spatial light modulator is at least one selected from the group consisting of 1, Tb, Dy, Er, Pr, Sm, Ho, Tm and their halides. 5. The spatial light modulator according to claim 1, wherein the molecular ratio of silicon oxide in the composite oxide thin film is in the range of 4% to 20%. 6. An insulator thin film is provided on at least one surface of the phosphor thin film, at least one island-shaped conductive film is provided on the surface of the insulator thin film, and at least bismuth is provided on the surface of the insulator thin film or the conductive film. A spatial light modulator provided with a composite oxide thin film containing silicon and silicon as main components, an optical mask,
An optical arithmetic device comprising at least a two-dimensional lens array.