JPH08106095A - Electrical-or optical-writing type liquid crystal spatial light modulator - Google Patents

Abstract

PURPOSE: To provide a high-contrast liquid crystal spatial light modulator which has more homogeneous oriented film layers and thereby, shows lesser unevenness of contrast by smoothing and homogenizing the undercoating layers of the oriented film layers of the optical modulator using oriented film layers formed basically with an oblique vapor deposition method. CONSTITUTION: This liquid crystal special light modulator is the one of electrical writing type obtained by successively forming a transparent substrate 1a, a transparent electrode layer 2a, an oriented film layer 6a, a liquid crystal composition layer 8, another oriented film layer 6b, another transparent electrode layer 2b and another transparent substrate 1b in this order, and also the one of the optical writing type obtained by successively forming a transparent substrate 1a, a transparent electrode layer 2a, a photoconductive film layer 3, a light-shielding film layer 4, a light reflection layer 5, an oriented film layer 6a, a liquid crystal composition layer 8, another oriented film layer 6b, another transparent electrode layer 2b and another transparent substrate 1b in this order. At this time, each of the oriented film layers 6a and 6b is an obliquely vapor-deposited layer consisting essentially of silicon monoxide or a layer formed by further modifying the surface of this vapor-deposited layer with a surfactant and also, the liquid crystal composition used is a nematic liquid crystal composition having negative anisotropy of the dielectric constant or a ferroelectric liquid crystal composition and further, smoothed layers 7a and 7b each consisting essentially of silicon dioxide are formed in the spaces between the oriented film layer 6a and the light reflection layer 5 and between the oriented film layer 6b and the transparent electrode layer 2b respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light used for spatially modulating light in optical measurement or optical information processing, or for amplifying image intensity in an image projection device such as a projector or a photosensitive printer. The present invention relates to an electric writing type liquid crystal spatial light modulator used in a writing type liquid crystal spatial light modulator or a liquid crystal display.

[0002]

2. Description of the Related Art In a conventional electric writing type spatial light modulator or optical writing type liquid crystal spatial light modulator, a nematic liquid crystal composition or a ferroelectric liquid crystal composition having a negative anisotropy of dielectric constant is used. As a method for orienting liquid crystal molecules in a specific one direction, silicon monoxide is vacuum-deposited or sputtered at a specific angle with respect to the normal direction of the transparent substrate to produce a silicon monoxide column having a specific directionality. Therefore, a means for forming an alignment film layer has been known.

[0003]

However, in the alignment film layer formed by the above-mentioned conventional method, the state of the silicon monoxide column is affected by the state of the surface on which the alignment film layer is formed. There is a problem in that the uniformity of orientation is disturbed. For example, I often used as a transparent electrode layer
Dielectric multilayer mirrors that are often used as TO (Indium-Tin-Oxide) and light reflecting layers often have uneven surface conditions depending on the film forming conditions, and as a result, the directionality of the silicon monoxide column is disturbed. There is a problem that the liquid crystal alignment state is deteriorated. Alternatively, in general, the material forming the transparent electrode layer and the material forming the reflective film layer are different materials. Therefore, when forming the alignment film layer on them, appropriate forming conditions should be applied to each. If it is not set, there is a problem that good liquid crystal orientation cannot be obtained. The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide.

[0004]

In the present invention, an electrically writable liquid crystal space composed of a transparent substrate, a transparent electrode layer, an alignment film layer, a liquid crystal composition, an alignment film layer, a transparent electrode layer and a transparent substrate in that order. An optical modulator and a transparent substrate, a transparent electrode layer, a photoconductive film layer, a light shielding film layer, a light reflection layer, an alignment film layer, a liquid crystal composition layer, an alignment film layer, a transparent electrode layer, and a transparent substrate in this order. In the optical writing type liquid crystal spatial light modulator, the alignment film layer is an oblique vapor deposition layer containing silicon monoxide as a main component, or a surface active material modified on the oblique vapor deposition layer, When the liquid crystal composition is a nematic liquid crystal composition having a negative dielectric constant anisotropy or a ferroelectric liquid crystal composition, in the case of forming the alignment film layer, the alignment film layer and the light reflection layer Silicon dioxide is mainly formed between the alignment film layer and the transparent electrode layer. Solved the above problems by the forming the smoothing layer configuration to.

[0005]

In the electric writing type liquid crystal spatial light modulator and the optical writing type liquid crystal spatial light modulator configured as described above, the smoothing layer is provided on the dielectric mirror or the transparent electrode layer as the light reflecting layer. Since the physical irregularities are filled and smoothed, the orientation of the silicon monoxide column of the orientation film layer formed thereon is made more uniform, so that the orientation of the liquid crystal molecules is made more uniform. Further, as the smoothing layer, the same material can be used both when it is formed on the transparent electrode layer and when it is formed on the light reflecting layer, so that it is formed on it. This has the effect of making the formation conditions of the alignment film layers to be the same.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing the structure of an optical writing type liquid crystal spatial light modulator having a smoothing layer according to the present invention. In FIG. 1, 1a and 1b are transparent substrates such as glass and plastic, 2a and 2b are transparent electrode layers such as ITO and tin oxide, 3 is a photoconductor layer made of hydrogenated amorphous silicon, selenium, cadmium sulfide, or the like, 4 Is a light-shielding film layer, 5 is a light reflecting layer made of a dielectric mirror, 6a and 6b are alignment film layers, 7a and 7b are smoothing layers, 8 is a liquid crystal composition layer,
9 is a spacer, 10 is writing light, and 11 is reading light.

The transparent substrates 1a and 1b are made of glass such as quartz glass or barium borosilicate glass, which is often used in a general thin film process, or general optical glass such as flint glass or crown glass, quartz, bismuth silicon single crystal, A transparent single crystal material such as sapphire, magnesium oxide single crystal, rutile single crystal, or a transparent acrylic resin or polycarbonate can be used. In general, an inorganic material is preferably used because a film forming process is required on the transparent substrates 1a and 1b. Further, as the transparent substrates 1a and 1b, it is preferable to use those having the flatness of the processed surface as small as possible and the surface roughness made small in order to affect the layer thickness of the liquid crystal composition layer 8. The transparent substrate used in the present invention had a reflected wavefront accuracy of λ / 4 or more on the liquid crystal composition layer side.

The formation method of the alignment film layers 6a and 6b differs depending on the type of liquid crystal composition. When the alignment film layers 6a and 6b are formed by the oblique vapor deposition method, the silicon monoxide raw material is heated and evaporated in a vacuum chamber. It is preferable to use the oblique vapor deposition method in which the silicon monoxide thin film is deposited and formed at an angle of 60 to 87 degrees with respect to the normal direction of the film formation surface. When the nematic liquid crystal composition having a negative dielectric anisotropy is vertically aligned with respect to the film forming surface, N, N dimethyl-N octadecyl is further formed on the silicon monoxide thin film formed by the oblique evaporation method. A method of forming a thin film layer of a surface-active substance such as 1-3-aminopropyltrimethoxysilyl chloride (DMOAP), octadecyltrimethoxysilane (ODS), and long-chain alcohol is widely used.

As the photoconductive layer, hydrogenated amorphous silicon formed by using the plasma chemical vapor deposition (PCVD) method has a film thickness of 1 to 1.
In many cases, a stack of 0 μm is used. The film thickness of this hydrogenated amorphous silicon is determined by the intensity of the writing light 10 and the impedance matching condition between the respective components of the optical writing type liquid crystal spatial light modulator.

The transparent electrode layers 2a and 2b are formed by stacking ITO with a film thickness of 0.02 to 0.3 μm. In the conventional optical writing type liquid crystal spatial light modulator, especially when the alignment film layer is formed by the oblique vapor deposition method, it is formed by the sputtering method or the high temperature vacuum vapor deposition method so that the ITO surface is not uneven. The configuration of the present invention does not require such consideration. However, in order to maximize the transmittance, 200 to 450 after film formation.
It is preferable to perform the annealing treatment at ℃. Further, in the present invention, the formed transparent electrode layer 2a or 2b is not structured to be patterned in a matrix, but when it is desired to use a plurality of spatial regions in parallel, these transparent electrode layers are formed into a thin film. It goes without saying that it may be processed and patterned into a matrix shape for use.

As the light-shielding layer 4, CdTe, SiGe compound, S
Inorganic compounds such as i and As ₃ Se ₂ or materials having a large light absorption coefficient such as phthalocyanine organic compounds are used in the range of 1 to 20.
μm to form a single-layer film structure, the above-mentioned inorganic compounds and inorganic compounds having a lower refractive index (for example, Si
O ₂ , MgF ₂ , ZnS, or ZnSe) is, for example, λ /
A dielectric mirror structure formed by alternately stacking four layers, or a composite of these single layer film structure and dielectric mirror structure is used. Light-shielding layer 4 used at this time
As a matter of course, when a metal material thin film having a large light absorption coefficient such as Cr or NiCr, but having an extremely large electric conductivity is used, a written image is not formed. In such a case, the metal material thin film used for the light-shielding layer 4 may be patterned in a matrix to a size such that the written image can be sufficiently sampled. Of course, when the read light 11 is weak enough not to affect the photoconductor layer 3 optically, the light shielding layer 4 may be omitted from the configuration of the optical writing type liquid crystal spatial light modulator of the present invention.

As the light reflection layer 5, TiO ₂ , ZrO ₂ , HfO ₂ ,
High refractive index dielectric material such as Ta ₂ O ₅ or Si ₃ N ₄ and SiO ₂ , Mg
F _2, ice saltpeter, to use a dielectric mirror formed by laminating a low refractive index dielectric materials alternately, for example, for each respective lambda / 4, such as CaF _2, or GeO ₂ are common. Of course, a metal material thin film having a high reflectance such as Al, Ag, Rh, Pt, or Au can be used as the light reflecting layer 5, but since these metal material thin films have high electric conductivity as described above, In this case, the metal material thin film must be patterned and used in a matrix shape so that the written image can be sufficiently sampled. Further, when a metal material thin film processed in a matrix is used as the light reflection layer 5, the light shielding layer 4 cannot be omitted because the read light 11 leaks from the matrix gap.

The smoothing layers 7a and 7b are made of organically modified SiO ₂
A solution of silicon alkoxide or silicon alkoxide is spread-coated on the surface of the film by spin coating or dipping, and then annealed at 150 to 500 ° C. to form the film. At this time, when the annealing temperature is as low as about 250 ° C. or lower, the organically modified SiO ₂ and the silicon alkoxide do not decompose sufficiently after the annealing and the organic component remains, but the surface is smoothed and formed by the oblique vapor deposition method. It does not affect the alignment state of the alignment film layers 6a and 6b. The annealing temperature is preferably 250 to 350 ° C. The film thickness of the smoothing layers 7a and 7b is 0.01 to 1 μm. This film thickness depends on the unevenness of the film-forming surface on which the smoothing layers 7a and 7b are formed.

The spacer 9 functions to control the thickness of the liquid crystal composition layer 8 and at the same time to shield the liquid crystal composition layer 8 from the influence of outside air. The spacer 9 seals a mixture of ultraviolet curable adhesive and thermosetting adhesive with silicon dioxide spheres or polymer spheres whose particle size is controlled in the vicinity of the thickness of the liquid crystal composition layer 8 and controlled. It was prepared by applying it to the area and then curing it. Of course, the layer thickness of the liquid crystal composition layer 8 may be controlled by dispersing these silicon dioxide spheres and polymer spheres in the liquid crystal composition layer 8. Therefore, it is not so preferable.

Further, the structure of the electric writing type liquid crystal spatial light modulator used for a liquid crystal display or the like is the same as the above-described optical writing type liquid crystal spatial light modulator except that the light shielding layer and the light reflecting layer are removed. Since the basic operation is the same as that of the optical writing type liquid crystal spatial light modulator, its explanation is omitted. However, the transparent electrode layer used in the electric writing type liquid crystal spatial light modulator has an electrode structure divided into a matrix shape facing each other, and a desired pixel is turned on / off by a thin film transistor or sequential signal synchronization. It goes without saying that the display of an image by performing the above-mentioned step is largely different from the configuration of the transparent electrode layer of the optical writing type liquid crystal spatial light modulator.

[0016]

【Example】

Example 1 An example in which a nematic liquid crystal composition having a negative dielectric anisotropy is used as the liquid crystal composition layer 8 will be described. At this time, as the transparent substrates 1a and 1b, synthetic quartz substrates, both surfaces of which were polished to a reflected wavefront accuracy of λ / 4 or more, were used. Further, the transparent electrode layer 2a has a thickness of 0.
An ITO thin film having a thickness of 14 μm was used, and an ITO thin film having a thickness of 0.17 μm was used as the transparent electrode layer 2b. Further, intrinsic hydrogenated amorphous silicon having a film thickness of 7 μm was formed as the photoconductive film layer 3 on the transparent substrate 1a. Further, as the light-shielding film layer 4, a CdTe compound having a thickness of 2 μm is formed, and a Si λ / 4 (λ = 650 nm) film is formed.
A layer in which three layers of SiO ₂ λ / 4 film (λ = 650 nm) were alternately laminated was used. Further, as the light reflection layer 5,
Six layers of λ ₂ film (λ = 650 nm) of TiO ₂ and SiO ₂ were laminated. Next, organically modified SiO ₂ was spin-coated on the light reflection layer 5 and the transparent electrode layer 2b and then annealed at 200 ° C. to form smoothing layers 7a and 7b of 0.03 μm. Then, SiO 2 was obliquely vapor-deposited at an angle of 83 to 87 degrees with respect to the normal to the substrate to form a base for the alignment film layers 6a and 6b. further,
The base of these alignment film layers is immersed in 0.0002-1% DMOAP aqueous solution at about 80 ° C., and then thoroughly washed and dried to obtain DMOA.
A P thin film was formed to form alignment film layers 6a and 6b.

The film thickness of the oblique vapor deposition film layer is 0.03 to 0.
It was 3 μm. The transparent substrate 1 thus formed into a film
A transparent substrate 1 is formed by printing and forming a seal area on a by using an epoxy adhesive mixed with polymer spheres having an average particle diameter of 2 to 8 μm.
A liquid crystal cell was formed by superimposing and pressing b. A nematic liquid crystal composition having a negative dielectric anisotropy is injected into the liquid crystal cell in a vacuum, and the injection port is sealed with an epoxy adhesive to produce the optical writing type liquid crystal spatial light modulator of the present invention. did.

A sine wave voltage having an amplitude of 20 to 40 V and a frequency of 500 to 10 KHz is applied between the transparent electrode layers 2a and 2b of the optical writing type liquid crystal spatial light modulator of the present invention thus manufactured, While irradiating the photoconductive film layer with the writing light 10,
Single-color readout light 1 which has a predetermined polarization state through the polarizer 1
When 1 was irradiated and the reading light from the optical writing type liquid crystal spatial light modulator of the present invention was observed through the analyzer, the contrast unevenness due to the alignment unevenness was hardly observed and the contrast of 3000 or more was obtained. When the same measurement was performed using a conventional optical writing type liquid crystal spatial light modulator having the same structure and no smoothing layer, a slight liquid crystal orientation unevenness was observed and the contrast was about 800 to 1200.

[Example 2] Similar to Example 1, an example will be described in which a nematic liquid crystal composition having a negative dielectric anisotropy is used as the liquid crystal composition layer 8. However, in this example, the alignment film layer 6b without the smoothing layer formed on the transparent electrode layer 2a was modified with the surface-active substance ODS. As the transparent substrates 1a and 1b, a synthetic quartz substrate having both surfaces polished to have a reflected wavefront accuracy of λ / 4 or more was used. Further, the transparent electrode layer 2a has a film thickness of 0.14.
An ITO thin film having a thickness of 0.17 μm was used as the transparent electrode layer 2b. Further, intrinsic hydrogenated amorphous silicon having a film thickness of 7 μm was formed as the photoconductive film layer 3 on the transparent substrate 1a. Further, as the light-shielding film layer 4, a CdTe compound having a film thickness of 2 μm is formed and three λ / 4 (λ = 650 nm) films of Si and λ / 4 films (λ = 650 nm) of SiO ₂ are alternately formed. Each layer was used. Furthermore, as the light reflection layer 5, TiO ₂
Six layers of SiO ₂ and λ / 4 film (λ = 650 nm) were laminated.

Next, organic modified SiO ₂ was spin-coated on the light reflecting layer 5 and then annealed at 150 ° C. to form a smoothing layer 7a of 0.05 μm. Then, SiO is obliquely vapor-deposited at an angle of 83 to 87 degrees with respect to the substrate normal, and the alignment film layer 6 is formed.
The base of a was formed. Further, the base of this alignment film layer and the transparent electrode layer 2b are formed by 0.0002 to 1% of ODS at about 70 ° C.
After being dipped in the aqueous solution, it was sufficiently washed and dried to form an ODS thin film to form alignment film layers 6a and 6b. The thickness of the oblique deposition film layer was 0.03 to 0.3 μm. A liquid crystal cell is formed by printing and forming a seal area on the transparent substrate 1a thus formed by film formation with an epoxy adhesive mixed with polymer spheres having an average particle diameter of 2 to 8 μm, and superposing and pressing the transparent substrate 1b. Was formed. A nematic liquid crystal composition having a negative dielectric anisotropy is injected into the liquid crystal cell in a vacuum, and the injection port is sealed with an epoxy adhesive to fabricate the optical writing type liquid crystal spatial light modulator of the present invention. did.

A sine wave voltage having an amplitude of 20 to 40 V and a frequency of 500 to 10 KHz is applied between the transparent electrode layers 2a and 2b of the optical writing type liquid crystal spatial light modulator of the present invention thus produced, While irradiating the photoconductive film layer with the writing light 10,
Single-color readout light 1 which has a predetermined polarization state through the polarizer 1
When 1 was irradiated and the reading light from the optical writing type liquid crystal spatial light modulator of the present invention was observed through the analyzer, the contrast unevenness due to the alignment unevenness was hardly observed and the contrast of 2800 or more was obtained. When the same measurement was carried out with a conventional optical writing type liquid crystal spatial light modulator having a similar structure and not provided with a smoothing layer, slight liquid crystal orientation unevenness was observed and the contrast was about 200 to 800.

[Example 3] An example in which a ferroelectric liquid crystal composition is used as the liquid crystal composition layer 8 will be described. At this time, as the transparent substrates 1a and 1b, a synthetic quartz substrate having both surfaces polished to have a reflected wavefront accuracy of λ / 8 or more was used. Further, an ITO thin film having a film thickness of 0.08 μm is used as the transparent electrode layer 2a, and a film thickness of 0.1 is used as the transparent electrode layer 1b.
A 4 μm ITO thin film was used. Furthermore, an intrinsic hydrogenated amorphous silicon film having a film thickness of 3 μm was formed as a photoconductive film layer 3 on the transparent substrate 1a. further,
As the light-shielding film layer 4, a λ / 4 (λ = 650 nm) film of Si and Si
A layer in which 5 layers of O ₂ λ / 4 film (λ = 650 nm) were alternately laminated was used. Furthermore, as the light reflection layer 5, Ti
Seven layers of O ₂ and SiO ₂ were laminated in a λ / 4 film (λ = 650 nm). Next, on the light reflection layer 5 and the transparent electrode layer 2b,
After spin-coating silicon alkoxide, it was annealed at 250 ° C. to form 0.05 μm smoothing layers 7a and 7b. Then, SiO was obliquely vapor-deposited at an angle of 75 to 85 degrees with respect to the substrate normal line to form alignment film layers 6a and 6b.
The thickness of the alignment film layer was 0.03 to 0.3 μm.

The transparent substrate 1a thus formed into a film
A seal region was printed on the above with an ultraviolet-curing adhesive containing silicon dioxide spheres having an average particle diameter of about 1 μm, and ultraviolet rays were irradiated while superposing and pressing the transparent substrate 1b to form a liquid crystal cell. A ferroelectric liquid crystal composition was injected into the liquid crystal cell in a vacuum, and the injection port was sealed with an epoxy adhesive to prepare an optical writing type liquid crystal spatial light modulator of the present invention.

Between the transparent electrode layers 2a and 2b of the optically writable liquid crystal spatial light modulator of the present invention thus produced, 1
It consists of repetition of positive voltage, negative voltage, and zero voltage of 0 to 20 V, and while applying a writing voltage 10 to the photoconductive film layer while applying a pulse voltage with a frequency of 100 to 1 KHz, a predetermined polarized light is passed through a polarizer. When the read light from the optical writing type liquid crystal spatial light modulator of the present invention was observed through the analyzer by irradiating the single-color read light 11 in the state, the contrast unevenness due to the uneven alignment was hardly observed. A contrast of 5000 was obtained. When the same measurement was performed using a conventional optical writing type liquid crystal spatial light modulator having the same configuration and no smoothing layer, a slight liquid crystal orientation unevenness was observed and the contrast was about 800 to 1800.

[Embodiment 4] An embodiment of an electric writing type liquid crystal spatial light modulator using a nematic liquid crystal composition having a negative dielectric anisotropy as the liquid crystal composition layer 8 will be described. At this time, as the transparent substrates 1a and 1b, synthetic quartz substrates, both surfaces of which were polished to a reflected wavefront accuracy of λ / 4 or more, were used. Further, the transparent electrode layers 2a and 2b have a film thickness of 0.
An ITO thin film of 08 μm was used. Further, the transparent electrode layers 2a and 2b are formed with a line width of 500 μm and a pitch of 550 μm.
After microfabrication into m-shaped stripes, they were arranged so as to be orthogonal to each other.

In this embodiment, the photoconductive film layer 3, the light shielding layer 4 and the light reflection layer 5 are not formed. Next, the transparent electrode layer 2
Silicon alkoxide was spin-coated on a and 2b and then annealed at 400 ° C. to form smoothing layers 7a and 7b of 0.06 μm. Then, SiO is obliquely vapor-deposited at an angle of 83 to 87 degrees with respect to the substrate normal, and the alignment film layer 6 is formed.
The bases of a and 6b were formed. Further, the bases of these alignment film layers were immersed in a 0.0002 to 1% DMOAP aqueous solution at about 80 ° C., and then sufficiently washed and dried to form DMOAP thin films to form alignment film layers 6a and 6b. The thickness of the oblique deposition film layer was 0.03 to 0.3 μm. A liquid crystal cell is formed by printing and forming a seal area on the transparent substrate 1a thus formed by film formation with an epoxy adhesive containing polymer spheres having an average particle diameter of 2 to 8 μm and superposing and pressing the transparent substrate 1b. Was formed. A nematic liquid crystal composition having a negative dielectric anisotropy is injected into the liquid crystal cell in a vacuum, and the injection port is sealed with an epoxy adhesive to fabricate the optical writing type liquid crystal spatial light modulator of the present invention. did.

A write voltage having an amplitude of 2 to 15 v is applied between the transparent electrode layers 2a and 2b of the optical writing type liquid crystal spatial light modulator of the present invention produced in this way, and a polarizer is interposed therebetween. When the read light from the electric writing type liquid crystal spatial light modulator of the present invention is observed through an analyzer, the read light 11 of a single color having a predetermined polarization state is transmitted. The resulting contrast unevenness was hardly observed, and a contrast of 3000 or more was obtained. In addition,
When the same measurement was performed using a conventional electric writing type liquid crystal spatial light modulator having a similar structure and no smoothing layer, a slight liquid crystal orientation unevenness was observed and the contrast was about 800 to 1800.

[Embodiment 5] An embodiment of an electric writing type liquid crystal spatial light modulator in which a ferroelectric liquid crystal composition is used as the liquid crystal composition layer 8 will be described. At this time, the transparent substrates 1a and 1b
For this, a synthetic quartz substrate, both surfaces of which were polished to have a reflected wavefront accuracy of λ / 4 or more, was used. In addition, the transparent electrode layer 2a
An ITO thin film having a thickness of 0.07 μm was used as and 2b. Further, these transparent electrode layers 2a and 2b were finely processed into a stripe shape having a line width of 500 μm and a pitch of 550 μm, and then arranged so as to be orthogonal to each other. In this embodiment, the photoconductive film layer 3, the light shielding layer 4 and the light reflection layer 5 are formed.
Has not formed. Next, organically modified SiO ₂ was spin-coated on the transparent electrode layers 2a and 2b and then annealed at 300 ° C. to form smoothing layers 7a and 7b of 0.02 μm. On top of that, at an angle of 75-85 degrees to the substrate normal
SiO 2 was obliquely vapor-deposited to form alignment film layers 6a and 6b. The film thickness of the oblique deposition film layer was 0.03 to 0.3 μm. The transparent substrate 1a thus formed into a film is printed with a UV curable adhesive containing silicon dioxide spheres having an average particle diameter of about 1 μm to form a seal region, and the transparent substrate 1b is superposed and pressurized, and then ultraviolet rays are applied. A liquid crystal cell was formed by curing.
A ferroelectric liquid crystal composition was injected into the liquid crystal cell in a vacuum, and the injection port was sealed with an epoxy adhesive to prepare an electrically writable liquid crystal spatial light modulator of the present invention.

While applying a write voltage with an amplitude of 2 to 15 v between the transparent electrode layers 2a and 2b of the optical write type liquid crystal spatial light modulator of the present invention thus produced, a polarizer is interposed. When the read light from the electric writing type liquid crystal spatial light modulator of the present invention is observed through an analyzer, the read light 11 of a single color having a predetermined polarization state is transmitted. The resulting contrast unevenness was hardly observed, and a contrast of 5000 or more was obtained. In addition,
When the same measurement was carried out with a conventional electric writing type liquid crystal spatial light modulator having a similar structure and not provided with a smoothing layer, a slight liquid crystal orientation unevenness was observed and the contrast was about 500 to 2,800.

[0030]

As described above, the liquid crystal spatial light modulator having the smoothing layer according to the present invention comprises a transparent substrate, a transparent electrode layer, an alignment film layer, a liquid crystal composition layer, an alignment film layer and a transparent electrode layer in this order. , An electric writing type liquid crystal spatial light modulator composed of a transparent substrate, a transparent substrate, a transparent electrode layer, a photoconductive film layer, a light shielding film layer, a light reflection layer, an alignment film layer, a liquid crystal composition layer, and an alignment layer in this order. Membrane layer,
In the optical writing type liquid crystal spatial light modulator composed of a transparent electrode layer and a transparent substrate, the alignment film layer is an oblique vapor deposition layer containing silicon monoxide as a main component, or on the oblique vapor deposition layer. A liquid crystal composition modified with a surface-active substance, wherein the liquid crystal composition is a nematic liquid crystal composition having a negative dielectric anisotropy or a ferroelectric liquid crystal composition, and the alignment film layer and the light reflection layer are As compared with the conventional optical writing type liquid crystal spatial light modulator, a smoothing layer containing silicon dioxide as a main component is formed between the alignment film layer and the transparent electrode layer. As a result, it was possible to realize an optical writing type liquid crystal spatial light modulator with high contrast and little contrast unevenness. This has a great effect on the improvement of image quality characteristics in the field of optical measurement that requires more uniform spatial light modulation characteristics, and in projectors and printers that require reproduction of higher quality images.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of an optical writing type liquid crystal spatial light modulator having a smoothing layer of the present invention.

[Explanation of symbols]

 1a, 1b Transparent substrate 2a, 2b Transparent electrode layer 3 Photoconductive film layer 4 Light-shielding layer 5 Light reflection layer 6a, 6b Alignment film layer 7a, 7b Smoothing layer 8 Liquid crystal composition layer 9 Spacer 10 Writing light 11 Reading light

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Rieko Sekura 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Industry Co., Ltd.

Claims (5)

[Claims] 1. A first transparent substrate, a first transparent electrode layer, a first alignment film layer, a liquid crystal composition layer, a second alignment film layer, in that order.
In the electric writing type liquid crystal spatial light modulator including a second transparent electrode layer and a second transparent substrate, the first and / or the second alignment film layer contains silicon monoxide as a main component. An orientated vapor deposition layer, or one obtained by modifying the orientated vapor deposition layer with a surface-active substance, wherein the liquid crystal composition is a nematic liquid crystal composition having a negative dielectric anisotropy, or a ferroelectric liquid crystal. A smoothing composition containing silicon dioxide as a main component between the first alignment film layer and the first transparent electrode layer, or between the second alignment film layer and the second transparent electrode layer. An electrically writable liquid crystal spatial light modulator, characterized in that a liquid crystal layer is formed. 2. A smoothing layer formed between the first alignment film layer and the first transparent electrode layer, and a smoothing layer formed between the second alignment film layer and the second transparent electrode layer. 2. The electrically writable liquid crystal spatial light modulator according to claim 1, wherein the materials of the smoothing layers are the same material. 3. A first transparent substrate, a first transparent electrode layer, a photoconductive film layer, a light-shielding film layer, a light reflection layer, a first alignment film layer, a liquid crystal composition layer, and a second alignment film layer in this order. , A second transparent electrode layer, and a second transparent substrate, wherein the first and / or the second alignment film layer contains silicon monoxide as a main component. Or a nematic liquid crystal composition having a negative anisotropy of the dielectric constant, or a ferroelectric liquid crystal composition. A liquid crystal composition, the smoothing layer containing silicon dioxide as a main component between the first alignment film layer and the light reflection layer, or between the second alignment film layer and the second transparent electrode layer. A liquid crystal spatial light modulator of optical writing type characterized by being formed. 4. A smoothing layer formed between the first alignment film layer and the light reflection layer, and a smoothing layer formed between the second alignment film layer and the second transparent electrode layer. The electrically writable liquid crystal spatial light modulator according to claim 3, wherein the materials of the functionalized layers are the same. 5. The electrically writable liquid crystal spatial light modulator according to claim 2, wherein the smoothing layer is formed by coating and baking organically modified silicon dioxide or silicon alkoxide. Optical writing type liquid crystal spatial light modulator.