JPH05100220A - Liquid crystal light valve - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal light valve which can form a high-contrast image and reduce the size of a device. CONSTITUTION:The liquid crystal light valve 10 is equipped with a light guide 11, glass substrates 12a and 12b, a transparent electrode 13, a clad layer 14, a metallic film 15, a photoconductor layer 16, a dielectric mirror 17, an electrode 19 for data transmission, orienting films 20a and 20b, and a liquid crystal layer 21. The light guide 11 is formed on the glass substrate 12a and a light signal for scanning is sent along the light guide 11. The transparent electrode 13 is formed on the light guide 11 and glass substrate 12a across the clad layer 14. On the transparent electrode 13, the photoconductor layer 15 which receives the light from the light guide 11 is formed. The electrode 19 for data transmission is provided on the glass substrate 12b. The glass substrates 12a and 12b where the orienting films 20a and 20b are formed are stuck together and a liquid crystal layer 21 is formed between the substrates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type image display device,
The present invention relates to a liquid crystal light valve used for a spatial light modulator, a parallel light arithmetic element, and the like.

[0002]

2. Description of the Related Art As an addressing method for forming an image according to an image signal on a liquid crystal light valve, there are an electric address, a laser thermal address, a light irradiation address and the like.

Regarding the electrical addressing method, there is a simple multiplex driving method liquid crystal light valve having a plurality of scanning electrodes and signal electrodes (matrix electrode structure) formed in a matrix along the X and Y directions. This is because scan electrodes X1, X2, ..., Xn and signal electrodes Y1, Y2,
, Ym are configured to selectively apply a voltage to any pixel, and a scanning signal and a data signal are transmitted by electric wiring.

Regarding the light irradiation addressing system, there is a liquid crystal light valve in which the liquid crystal and the photoconductor layer are sandwiched between glass substrates with transparent electrodes, and the liquid crystal can be directly addressed by light irradiation.

FIG. 15 is a sectional view showing the structure of a conventional light irradiation address type liquid crystal light valve.

This light irradiation address type liquid crystal light valve is disclosed in J. J. Grinberg, A. A. Jacobson, W. W. Bleha
), Elle. L. Miller, Elle. Frass (L.Fra
as), Dee. D. Boswell and
) Gee. G.Myer, “Anu Real-
Time Noncoherent To Coherent Light Image Converter (A New Real-Time Noncoher
ent to Coherent Light Image Converter): The Hybrid Field Effect Liqu
id Crystal Light Valve) ”, Optical Engineering (Opt. Eng.) Volume (Vol.) 14, 217 (197
It is the general one shown in 5).

As shown in the figure, a light irradiation address type liquid crystal light valve 400 includes glass substrates 401a and 401b, transparent electrodes 402a and 402b, a photoconductor layer 403, and a dielectric mirror 404.
, Alignment films 405a and 405b, a sealant 406, a liquid crystal layer 407, and an AC power supply 408.

The transparent electrode 402a of the liquid crystal light valve 400
A voltage is applied between AC power supply 402 and 402b by the AC power supply 408. Address (writing) light 40 from the glass substrate 401b side
When 9 is incident, the impedance of the photoconductor layer 403 decreases in the light-exposed region (bright state), and the voltage applied by the AC power supply 408 is applied to the liquid crystal layer 407. On the other hand, in a region not exposed to light (dark state), the impedance of the photoconductor layer 403 does not change and no voltage is applied to the liquid crystal layer 407.

Due to such a difference between the bright state and the dark state, image information corresponding to the address light 409 is formed, and this image information can be read by the reading light 410.

The liquid crystal light valve 400 as described above is applied to a projection type image display device, a parallel optical operation element and the like.

Further, there is an address type liquid crystal light valve which is a combination of the above-mentioned electric addressing system and light irradiation addressing system. For example, as disclosed in Japanese Patent Laid-Open No. 2-314617, there is one that transmits a data signal of an electrical address system by light.

[0012]

In such a conventional electric address type liquid crystal light valve of the simple multiplex drive system, since the divided voltage is applied to pixels other than the display pixel, the display contrast is lowered. There is a problem. Further, the data signal useful for controlling the display state is applied only for a certain time determined by the duty ratio in time, and the data signal not related to the control of the display state is applied for most of the remaining time. Has a problem that it also responds to such a non-selected data signal. As a measure for solving these problems, in the simple multiplex drive system having a matrix electrode configuration,
For example, a method called a voltage averaging method is generally used.

However, the margin of the operating voltage in the voltage averaging method decreases as the number n of scanning electrodes increases. Therefore, when the steepness of the electro-optical characteristics of the liquid crystal material is constant, a practical display is performed. Number of scanning electrodes that can maintain quality n
However, there is a problem that a higher resolution or a larger screen cannot be obtained.

On the other hand, in the conventional light irradiation addressing type liquid crystal light valve, an address light source such as a cathode ray tube (CRT) or a liquid crystal panel is required in addition to the liquid crystal light valve element, and the size of the device cannot be reduced. is there.

Further, an address system combining a conventional electrical address system and a light irradiation address system (Japanese Patent Laid-Open No. 2-1346)
In 17), since the waveform of the data signal is converted into light intensity change and written in the photoconductor layer, a highly sensitive photoconductor layer capable of coping with weak light intensity change is required. Further, since an image is displayed uniformly on the screen, there is a problem that a photoconductor layer having an extremely uniform sensitivity distribution is required.

Therefore, it is an object of the present invention to provide a liquid crystal light valve which can form a high-contrast image and can be miniaturized.

[0017]

A liquid crystal light valve according to the present invention includes a liquid crystal layer provided between a first substrate and a second substrate each having a transparent electrode, a liquid crystal layer and a first liquid crystal layer. And a photoconductor layer that is provided between the photoconductor layer and the substrate, the impedance of which changes with incident light, and an optical waveguide that irradiates the photoconductor layer with light from the first substrate side.

In the liquid crystal light valve according to the present invention, the optical waveguide is formed in a stripe shape on the first substrate, and
The transparent electrodes formed on the substrate are patterned in stripes.

In the liquid crystal light valve according to the present invention, the transparent electrode formed on the first substrate is formed in a stripe shape parallel to the optical waveguide.

In the liquid crystal light valve according to the present invention, the optical waveguide is formed of a polymer waveguide.

In the liquid crystal light valve according to the present invention, the optical waveguide is formed of an electroluminescence element.

Further, in the liquid crystal light valve according to the present invention, the first substrate includes two substrates, and the optical waveguide includes the first optical waveguide formed on one of the two substrates and the two substrates. It includes a second optical waveguide formed on the other side.

In the liquid crystal light valve according to the present invention, the substrate formed on the liquid crystal layer side of the two substrates is formed of a fiber plate.

In the liquid crystal light valve according to the present invention, at least one of the first optical waveguide and the second optical waveguide is formed of an electroluminescence element.

[0025]

When the photoconductor layer is irradiated with light from the side of the first substrate by the optical waveguide, the impedance of the photoconductor layer changes and the scanning line is selected. The impedance of the photoconductor layer in the selected portion irradiated with the light from the optical waveguide is smaller than the impedance of the liquid crystal layer.
Therefore, most of the data signal applied to the transparent electrode provided on the first substrate is applied to the liquid crystal layer. On the other hand, in the photoconductor layer in the non-selected portion where the light from the optical waveguide is not irradiated, the impedance of the photoconductor layer is larger than the impedance of the liquid crystal layer, so that the data signal not related to the control of the display state is It is no longer applied to the layer.

As described above, since the scanning signal is transmitted by the light from the optical waveguide, the non-selection unit is different from the case where the scanning signal is transmitted through the electric wiring in the conventional liquid crystal light valve of the simple multiplex drive system. Therefore, the data signal is not always applied to the liquid crystal corresponding to. Therefore, the bias ratio of the voltage applied to the liquid crystal layer in the selected portion and the non-selected portion of the scanning line becomes large, so that a high-contrast image can be formed.

Further, since the address light source other than the liquid crystal light valve is not required, the miniaturization of the entire device can be realized.

Further, in the present invention, the scanning signal (pulse waveform)
Is converted into light on / off and written into the photoconductor layer, so that the photoconductor layer used here only needs to exhibit an impedance equal to or higher than a certain threshold value at the time of light irradiation. Therefore, the photoconductor layer is not required to have high performance as compared with the case where a data signal is converted into a change in light intensity and then written, which is advantageous in production.

Further, according to the present invention, since the scanning signal is transmitted by the light from the electroluminescence element which is the scanning optical signal source, the electrical wiring is provided in the conventional liquid crystal light valve of the simple matrix drive system having the matrix electrode structure. As compared with the case where the scanning signal is transmitted via the data line, the data signal is not constantly applied to the liquid crystal corresponding to the non-selected portion, and the bias ratio of the voltage applied to the liquid crystal layer in the selected portion and the non-selected portion of the scanning line Is large, a high-contrast image can be formed.

In the present invention, 2 included in the first substrate
Since the optical waveguide is formed on each of the two substrates, it is possible to eliminate the gap between the scanning lines and increase the number of scanning lines. Thereby, the resolution and the aperture ratio can be improved.

In the present invention, 2 included in the first substrate
Of the two substrates, the substrate formed on the liquid crystal layer side is formed of a fiber plate, so that crosstalk caused by light leakage can be prevented.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a schematic configuration of a first embodiment of a liquid crystal light valve according to the present invention.

As shown in the figure, the liquid crystal light valve 10 of this embodiment includes an optical waveguide 11, glass substrates 12a and 12b, a transparent electrode 13, a clad layer 14, a metal film 15, a photoconductor layer 16 and a dielectric mirror. 17, data transmission electrode 19, alignment films 20a and 20
b, and a liquid crystal layer 21.

The optical waveguide 11 is formed in a stripe (thin line) shape on the glass substrate 12a by an ion exchange method using heat and an electric field, and an optical signal for scanning is transmitted along the optical waveguide 11.

In this embodiment, the light emitting diode (LE
In order to be able to guide light with poor directivity such as D),
Although a multimode thallium (Tl) ion exchange waveguide is used as the optical waveguide 11, silver (Ag) ions or the like may be used.

The transparent electrode 13 is made of indium oxide (ITO) doped with tin, and is formed on the optical waveguide 11 and the glass substrate 12a via the clad layer 14 by the sputtering method. The transparent electrode 13 may be patterned in a stripe shape so as to overlap the optical waveguide 11.

The clad layer 14 is deposited between the glass substrate 12a and the optical waveguide 11 and the transparent electrode 13 by the sputtering method, and is provided because the transparent electrode 13 has a refractive index higher than that of the optical waveguide 11. There is.

The cladding layer 14 is made of, for example, silicon dioxide (SiO ₂ ) which is a low refractive index derivative, and S
The film thickness of iO ₂ needs to be set so that the optical waveguide 11 causes an appropriate light leakage as a light emitting source, and the range of 500 angstroms to 5000 angstroms is suitable. In this embodiment, for example, the film thickness of SiO ₂ is 3000 Å.

On the back surface of the glass substrate 12a, that is, the surface opposite to the surface on which the optical waveguide 11 is formed, a metal film 15 for blocking light from other than the optical waveguide 11 is provided.

The metal film 15 can be formed of Ag, aluminum (Al), molybdenum (Mo), or the like.
Further, a pigment dispersion type light-shielding film used for a color filter of a liquid crystal panel or the like can be used instead of the metal film 15.

A photoconductor layer 16 for receiving light from the optical waveguide 11 is formed on the transparent electrode 13, and the photoconductor layer 16 is made of, for example, amorphous silicon hydride (a-Si: H). And is formed by the plasma CVD (Chemical Vapor Deposition) method.

In addition to a-Si: H, the photoconductor layer 16 may be bismuth silicate (Bi ₁₂ SiO 2) as long as it has a characteristic that the impedance changes according to the amount of light irradiation.
₂₀ ), cadmium sulfide (CdS), amorphous hydrogenated silicon carbide (a-SiC: H), amorphous hydrogenated silicon oxide (a-SiO: H), and amorphous hydrogenated silicon nitride (a- SiN: H) or the like may be used.

However, as a method of suppressing the dark current of the photoconductor layer 16 to a low level, there is a method of forming a blocking electrode structure utilizing the selective permeability of carriers. For example, photoconductor layer
When 16 is a-Si, a thin a-Si layer of n-type doped with phosphorus (P) and p-type doped with boron (B) is used to form a pin diode structure or a back-to-back diode structure such as pinip. Good. There is also a method of forming a blocking electrode structure by a Schottky junction or a heterojunction with a wide gap material, which requires a very thin (50 Å to 300 Å) SiO ₂ or silicon nitride (SiN _x ) film. Depending on the photoconductor layer
16 may be provided on one side or both sides.

On the photoconductive layer 16, titanium dioxide (Ti
A dielectric mirror 17 made of a multilayer film in which O ₂ ) and SiO ₂ are alternately laminated is formed by an electron beam (EB) vapor deposition method.

It should be noted that the photoconductor layer 16 is formed through the dielectric mirror 17.
In order to prevent the reading light 18 from leaking, a light shielding layer may be provided between the dielectric mirror 17 and the photoconductor layer 16. As the light-shielding layer, a carbon-dispersed organic thin film, cadmium telluride (CdTe), and Ag electroless-plated aluminum oxide (Al ₂ O ₃ ) can be used.

A glass substrate facing the glass substrate 12a
A data transmission electrode 19 is provided on 12b, and the data transmission electrode 19 is formed by patterning ITO deposited by a sputtering method in a stripe shape.

Alignment films 20a and 20b are formed on the dielectric mirror 17 and the data transmission electrode 19 by applying a polyimide film by spin coating and baking, and the surfaces of the alignment films 20a and 20b are A molecular orientation treatment by rubbing is performed.

The glass substrates 12a and 12b on which the alignment films 20a and 20b are formed are provided with a spacer (not shown) so that the data transmission electrode 19 and the scanning optical waveguide 11 are in a vertical positional relationship. A liquid crystal layer 21 is formed by injecting liquid crystal into a space composed of the alignment films 20a and 20b and the spacers, which are bonded to each other and sealed.

The liquid crystal forming the liquid crystal layer 21 has a larger impedance than the impedance of the photoconductor layer 16 selected as a scanning line by light irradiation, and compared with the impedance of the nonselected photoconductor layer 16. Select a liquid crystal that becomes smaller.

The glass substrates 12a and 12b are examples of the first and second substrates of the present invention. The optical waveguide 11 is an embodiment of the optical waveguide of the present invention. Photoconductor layer 16 is an example of the photoconductor layer of the present invention. The liquid crystal layer 21 is an example of the liquid crystal layer of the present invention.

In the liquid crystal light valve having the above-mentioned structure, the impedance of the liquid crystal layer 21 is much larger than the impedance of the photoconductor layer 16 selected as the scanning line by light irradiation, so that the voltage is applied between the electrodes. Most of the data signals are applied to the liquid crystal layer 21. However, the impedance of the photoconductor layer 16 which is not illuminated is
Since the impedance is higher than that of the liquid crystal layer 21, the data signal is not applied to the liquid crystal layer 21.

Therefore, according to this embodiment, since the scanning signal is transmitted by the light from the optical waveguide, the scanning signal is transmitted through the electric wiring in the conventional simple multiplex drive type liquid crystal light valve having the matrix electrode structure. Is transmitted, the data signal is not always applied to the liquid crystal corresponding to the non-selected portion.

Therefore, since the bias ratio of the voltage applied to the liquid crystal layer in the selected portion and the non-selected portion of the scanning line becomes large, it is possible to form a high-contrast image and delay the signal waveform due to the wiring resistance or capacitance. Since this does not occur, a large-scale device or a high-density device can be realized.

Further, since the margin of the operating voltage in the voltage averaging method, which is limited by the normal number of scanning lines, can be increased, higher resolution or a large screen can be obtained.

Furthermore, gradation display is also possible by modulating the waveform of the data signal.

In the above embodiment, the optical waveguide 11 is configured so as to share one surface of the glass substrate 12a, but the optical waveguide may be provided inside the glass substrate. Good.

FIG. 2 is a schematic configuration diagram of a drive unit of the liquid crystal light valve 10 shown in FIG. For simplicity, no signal or timing generator is shown in the figure.

As shown in the figure, the drive unit of the liquid crystal light valve 10 of FIG. 1 is a drive circuit 26 for driving the LED array 25 for scanning signals and the data transparent electrode 19 included in the liquid crystal light valve 10. It has and.

A semiconductor laser (LD) may be used instead of the LED array 25.

The LED array 25 is connected to the liquid crystal light valve 10, and the light pulse signal emitted from the LED array 25 is guided to the liquid crystal light valve 10.

FIG. 3 is a perspective view showing details of the connecting portion of the LED array 25 of FIG.

As shown in the figure, the light emitted from the LED array 25 is guided to the optical waveguide of the liquid crystal light valve 10 via the optical lens array 27.

Incidentally, instead of using the optical lens array 27 as described above, the end face of the optical waveguide of the liquid crystal light valve 10 and the light emitting face of the LED array 25 may be directly coupled.

The reflecting mirror 28 is provided for reflecting the light on the end face of the optical waveguide and efficiently guiding the light to the photoconductor layer, and is made of Al, Ag or the like.

FIG. 4 is a schematic block diagram showing an embodiment of a device when the liquid crystal light valve 10 shown in FIG. 1 is applied to a projection type image display device.

As shown in the figure, the projection type image display device of this embodiment is provided with a liquid crystal light valve 10, a lamp 31, a lens 32, a polarization beam splitter 33, a lens 34 and a screen 35.

When the light from the lamp 31 is incident on the liquid crystal light valve 10 on which an image is formed via the lens 32 and the polarization beam splitter 33, the portion where the alignment state of the liquid crystal layer of the liquid crystal light valve 10 is changed. Since the polarization direction of the transmitted light changes due to the electro-optical effect, the reflected light can be transmitted through the polarization beam splitter 33. This reflected light is magnified by the lens 34 and thus the liquid crystal light valve.
The image formed on 10 is projected on the screen 35.

The liquid crystal light valve according to the present invention does not require an address light source such as a CRT or a liquid crystal panel unlike the conventional optical address type liquid crystal light valve, and therefore the overall size of the device can be reduced.

The operation mode of the liquid crystal layer of the liquid crystal light valve 10 used here is a hybrid electric field effect mode using nematic liquid crystal, but in addition to this, a twisted nematic mode, a super twisted nematic mode and an electric field induced birefringence are used. Modes may be used.

Besides, ferroelectric liquid crystals, antiferroelectric liquid crystals and smectic liquid crystals having an electroclinic effect can be used. Further, the polarization beam splitter 33 is omitted by using a phase transfer mode using a nematic liquid crystal, a dynamic scattering mode and a guest host mode, and a guest host mode using a liquid crystal composite film and a smectic liquid crystal. Is possible.

Next, a second embodiment of the present invention will be described.

FIG. 5 is a sectional view showing the schematic construction of the second embodiment of the liquid crystal light valve according to the present invention.

As shown in the figure, the liquid crystal light valve 40 of this embodiment includes an optical waveguide 41, glass substrates 42a and 42b, a transparent electrode 43, a clad layer 44, a metal film 45, a photoconductor layer 46, a dielectric mirror. 47, data transmission electrode 49, alignment films 50a and 50
b, and a liquid crystal layer 51.

The optical waveguide 41 is formed in a stripe (thin line) shape on the glass substrate 42a by an ion exchange method using heat and an electric field, and an optical signal for scanning is transmitted along the optical waveguide 41.

In this embodiment, a multi-mode Tl ion-exchange waveguide is used as the optical waveguide 41 so that it can guide light having bad directivity such as an LED.
Ions or the like may be used.

The transparent electrode 43 is formed by patterning in stripe shape from ITO doped with tin, and is formed on the optical waveguide 41 and the glass substrate 42a via the clad layer 44 by the sputtering method.

The ITO pattern forming the transparent electrode 43 is parallel to the stripe pattern of the optical waveguide 41 by 1 /
It is formed by shifting by 2 pitches. Also, the transparent electrode 43
The portion excluding the ITO is made of an insulator 52 such as SiO _{2 in} order to prevent leakage between the transparent electrodes 43. Therefore, the optical waveguide 41 and the insulator 52 are configured to overlap each other with the clad layer 44 interposed therebetween.

The clad layer 44 is deposited between the glass substrate 42a and the optical waveguide 41 and the transparent electrode 43 by a sputtering method, and is provided because the refractive index of the transparent electrode 43 is larger than that of the optical waveguide 41. There is.

The clad layer 44 is formed of, for example, SiO ₂ which is a low refractive index derivative, and the film thickness of SiO ₂ must be set so that the optical waveguide 41 causes appropriate light leakage as a light emitting source. A suitable range is 500 angstroms to 5000 angstroms. In this embodiment, for example, the film thickness of SiO ₂ is 3000 Å.

On the back surface of the glass substrate 42a, that is, the surface opposite to the surface on which the optical waveguide 41 is formed, a metal film 45 for blocking light other than the optical waveguide 41 is provided.

The metal film 45 can be formed of Ag, Al, Mo or the like. It is also possible to use a pigment dispersion type light-shielding film used for a color filter of a liquid crystal panel instead of the metal film 45.

A photoconductor layer 46 for receiving light from the optical waveguide 41 is formed on the transparent electrode 43. The photoconductor layer 46 is made of, for example, a-Si: H, and is formed by a plasma CVD method. Has been formed.

In addition to a-Si: H, the photoconductor layer 46 may be made of Bi ₁₂ SiO ₂₀ , CdS, a as long as it has a characteristic that the impedance changes according to the irradiation amount of light. −
You may use SiC: H, a-SiO: H, a-SiN: H, etc.

However, as a method of suppressing the dark current of the photoconductor layer 46 to a low level, there is a method of forming a blocking electrode structure utilizing the selective permeability of carriers. For example, photoconductor layer
When 46 is a-Si: H, a thin a-Si: H layer of n-type doped with P and p-type doped with B is preferably used to form a pin diode structure or a back-to-back diode structure such as pinip.

There is also a method of forming a blocking electrode structure by a Schottky junction or a heterojunction with a wide gap material, which requires a very thin (50 Å to 300 Å) SiO ₂ or SiN _x film or the like. Accordingly, it may be provided on one surface or both surfaces of the photoconductor layer 46.

TiO ₂ and SiO ₂ are deposited on the photoconductor layer 46.
E is a dielectric mirror 47 composed of a multilayer film in which and are alternately laminated.
It is formed by the B vapor deposition method.

The photoconductive layer 46 is formed through the dielectric mirror 47.
In order to prevent the reading light 48 from leaking, a light shielding layer may be provided between the dielectric mirror 47 and the photoconductor layer 46. As the light-shielding layer, a carbon-dispersed organic thin film or CdT
It is possible to use Al ₂ O ₃ or the like that has been subjected to electroless plating of e and Ag.

A glass substrate facing the glass substrate 42a
42b is provided with a data transmission electrode 49, and the data transmission electrode 49 is formed by patterning ITO deposited by a sputtering method in a stripe shape.

Alignment films 50a and 50b are formed on the dielectric mirror 47 and the data transmission electrode 49 by applying a polyimide film by spin coating and baking, respectively. The surfaces of the alignment films 50a and 50b are A molecular orientation treatment by rubbing is performed.

The glass substrates 42a and 42b on which the alignment films 50a and 50b are formed are provided with spacers (not shown) so that the data transmission electrode 49 and the scanning optical waveguide 41 are in a vertical positional relationship. A liquid crystal layer 51 is formed by injecting liquid crystal into a space composed of the alignment films 50a and 50b and the spacers, which are bonded to each other and sealed.

The impedance of the liquid crystal forming the liquid crystal layer 51 is higher than the impedance of the photoconductor layer 46 selected as a scanning line by light irradiation and is higher than the impedance of the nonselected photoconductor layer 46. Select a liquid crystal that becomes smaller.

The glass substrates 42a and 42b are examples of the first and second substrates of the present invention. The optical waveguide 41 is an embodiment of the optical waveguide of the present invention. Photoconductor layer 46 is an example of the photoconductor layer of the present invention. The liquid crystal layer 51 is an example of the liquid crystal layer of the present invention.

Since the impedance of the liquid crystal layer 51 is much larger than the impedance of the photoconductor layer 46 selected as a scanning line by light irradiation, most of the data signal applied between the electrodes is the liquid crystal layer 51. Applied to. However, since the impedance of the photoconductor layer 46 which is not irradiated with light becomes larger than the impedance of the liquid crystal layer 51, the data signal is not applied to the liquid crystal layer 51.

In the liquid crystal light valve 40 having the above-mentioned structure, the two transparent electrodes 43 for scanning come into contact with one photoconductive layer 46 selected as a scanning line by light irradiation, and one of the scanning transparent electrodes 43 for scanning one. The scanning line is divided into two by synchronously scanning so that the data signal is applied only to the transparent electrode 43. That is, according to this embodiment, not only a high-contrast image can be obtained as in the liquid crystal light valve according to the first embodiment, but also the resolution can be doubled.

In the above embodiment, the optical waveguide 11 is configured so as to share one surface of the glass substrate 12a, but the optical waveguide may be provided inside the glass substrate. Good.

The structure of the drive unit of the liquid crystal light valve 40 of the second embodiment shown in FIG. 5 is the same as that of the drive unit shown in FIG. 2, and the drive unit of the liquid crystal light valve 40 of the second embodiment is the same. The structure of the connection part of the LED array included in FIG. Also, liquid crystal light valve 40
The configuration and the operation mode of the liquid crystal layer of the projection type image display device using is the same as the configuration and the operation mode of the liquid crystal layer of the projection type image display device shown in FIG.

Next, a third embodiment of the present invention will be described.

In the drive section of the liquid crystal light valve of the first embodiment, as shown in FIG. 2, an LED is used as an optical signal source for scanning.
The array 25 is included, and in the case of such a configuration, a high degree of accuracy is required for alignment between the end surface of the optical waveguide of the liquid crystal light valve and the LED array. In order to improve this point, in the liquid crystal light valve of the third embodiment of the present invention,
An LED section including an LED array and an optical waveguide are formed adjacent to each other on the same substrate.

FIG. 6 is a sectional view of a substrate including an optical waveguide and an LED portion included in a liquid crystal light valve according to a third embodiment of the present invention.

As shown in the figure, an LED section 62 and an optical waveguide 63 are formed adjacent to each other on a substrate 61 made of Si single crystal.

The LED section 62 is formed as a pin structure made of a-Si _x C ₁ -x: H. This material can be formed at a relatively low temperature and has high brightness. Incidentally, or provide a buffer layer of the GaP may be used, such as Al _X Ga _1-X As based LED by using a Si off-substrate.

In this case, the LED portion is adjusted by adjusting the composition ratio X.
Since the emission wavelength range of the LED included in 62 can be changed, the emission wavelength can be changed according to the sensitivity of the photoconductor layer, which is advantageous for improving the performance.

The optical waveguide 63 is composed of a core layer 65 made of SiO ₂ —GeO ₂ and a cladding layer 66 made of SiO ₂ . Thus, the optical waveguide 63 made of SiO ₂ system
Is formed by the CVD method using the oxidation reaction of SiCl ₄ gas and GeCl ₄ gas, but it can also be formed by the flame deposition method. In this formation, Si formed by using TiCl ₄ gas instead of GeCl ₄ gas.
O ₂ —TiO ₂ may be used as the core layer.

The electrodes 64a and 64b of the LED are provided above and below the LED section 62, respectively. Electrode 64a
As the material of 64 and 64b, a transparent electrode or a metal electrode can be used in the case of an LED composed of a-Si _x C _1-x : H, and a transparent electrode or a metal electrode can be used in the case of an LED composed of Al _x Ga _1-x As The substrate 61 made of Si single crystal can be used as an electrode.

As described above, since the LED section 62 and the optical waveguide 63 are formed adjacent to each other on the same substrate 61, the LED section
The light emitted from 62 is guided to the optical waveguide 63 located on the side of the LED section 62.

Optical waveguides 11 and 41 of the first and second embodiments
Other configurations of the liquid crystal light valve of the third embodiment, which includes the substrate 61 on which the LED section 62 and the optical waveguide 63 are formed as described above, instead of the glass substrates 12a and 42a on which The structure is basically the same as that of the liquid crystal light valve of the first or second embodiment.

According to this embodiment, it is possible to obtain a high-contrast image as in the liquid crystal light valves according to the first and second embodiments, and it is possible to reduce the size of the apparatus.

Furthermore, the alignment of the LED section 62 and the optical waveguide 63 depends on the photolithography process, and simple and highly accurate alignment is possible.

In this embodiment, since the substrate 61 functions as a light shielding layer for visible light, it is not necessary to provide a metal film corresponding to the metal films 15 and 45 of the first and second embodiments.

Next, a fourth embodiment of the present invention will be described.

FIG. 7 is a sectional view showing the schematic construction of the fourth embodiment of the liquid crystal light valve according to the present invention.

As shown in the figure, the liquid crystal light valve 80 of this embodiment includes an optical waveguide 81, glass substrates 82a and 82b, a transparent electrode 83, a clad layer 84, a metal film 85, a photoconductor layer 86, a dielectric mirror. 87, data transmission electrode 89, alignment films 90a and 90
b, and a liquid crystal layer 91.

The optical waveguide 81 is a polymer waveguide, and is formed of a waveguide formed by photopolymerization of polycarbonate Z. The striped pattern of the optical waveguide 81 can be formed by a photolithography process during photopolymerization.
As the polymer waveguide, polyurethane, epoxy, photosensitive plastic, photoresist or the like can be used in addition to the above.

Between the optical waveguide 81 and the dielectric mirror 87,
A clad layer 84 is provided to prevent light leakage from the optical waveguide 81 to the dielectric mirror 87.

The clad layer 84 is formed by coating a resin having a refractive index smaller than that of the optical waveguide 81.

Structures and materials of the glass substrates 82a and 82b, the transparent electrode 83, the metal film 85, the photoconductor layer 86, the dielectric mirror 87, the data transmission electrode 89, the alignment films 90a and 90b, and the liquid crystal layer 91. Is the same as in the first or second embodiment.

The glass substrates 82a and 82b are examples of the first and second substrates of the present invention. The optical waveguide 81 is an embodiment of the optical waveguide of the present invention. Photoconductor layer 86 is an example of the photoconductor layer of the present invention. The liquid crystal layer 91 is an example of the liquid crystal layer of the present invention.

Therefore, according to the configuration of this embodiment, the first
Also, similarly to the liquid crystal light valve according to the second embodiment, it is possible to obtain a high-contrast image and realize the downsizing of the device.

Further, in the above-mentioned first and second embodiments of the present invention, the process temperature of the photoconductor layers 16 and 46 (for example, a-
In the case of SiC: H, the optical waveguide 11
Ion exchange glass waveguides with high heat resistance are used for 41 and 41, and the photoconductor layer is formed after forming the optical waveguides 11 and 41.
16 and 46 are formed.

However, according to the structure of this embodiment, the photoconductor layer 86 is more glass substrate 82 than the optical waveguide 81.
Since the structure is provided near a, it is possible to form the optical waveguide 81 having weak heat resistance such as the polymer waveguide after forming the photoconductor layer 86. Therefore, a polymer waveguide having weak heat resistance can be used as the optical waveguide 81.

In the liquid crystal light valves of the above-mentioned first to fourth embodiments, polarizing plates are provided on both surfaces of the liquid crystal light valve in a crossed Nicol state, and the liquid crystal layer of the liquid crystal light valve has a ferroelectric property having a memory property. By using a volatile liquid crystal, it can be used for a two-dimensional optical operation element.

Next, a fifth embodiment of the present invention will be described.

In this embodiment, an EL (electroluminescence) element is used instead of the optical waveguide serving as a scanning optical signal source.

FIG. 8 is a perspective view showing the schematic construction of the fifth embodiment of the liquid crystal light valve according to the present invention. 9 is shown in FIG.
2 is a cross-sectional view taken along line AA of FIG.

In FIG. 8, the light emitting layer is thinned and EL is generated by an AC power source.
The structure when the device is driven is shown.

As shown in these figures, the liquid crystal light valve 100 of this embodiment includes glass substrates 101 and 113, a back electrode 102, a lower insulating layer 103, a light emitting layer 104, and an upper insulating layer 10.
5, a transparent electrode 106, a photoconductor layer 107, a light shielding layer 108, a dielectric mirror 109, alignment films 110a and 110b, a liquid crystal layer 111, a data transmission electrode 112, a sealing material 114 and a metal film 115.

A method of manufacturing the liquid crystal light valve 100 will be described.

In the liquid crystal light valve 100 of this embodiment,
In order to obtain stable light emission from the EL element, a sandwich structure in which a light emitting layer is sandwiched by insulating layers is used.

First, the back electrode 102 is formed on the glass substrate 101. Al (aluminum) is used for the back electrode 102, a film is formed by an EB vapor deposition method, and then an etching process is performed, and the back electrode 102 is formed by patterning in a stripe shape.

In addition to Al, Ti (titanium), Mo, or the like may be used for the back electrode 102.

In this embodiment, the back electrode 102 is formed in a stripe shape. However, the shape of the back electrode 102 is not limited to the stripe shape, and various arrangements of light emitting pixels can be designed by changing the shape. Is possible.

Then, as an insulating layer for applying a stable high electric field to the light emitting layer 104 between the back electrode 102 and the transparent electrode 106, a lower insulating layer 103 is provided on the back electrode 102 side and an upper layer is provided on the transparent electrode 106 side. The insulating layer 105 is formed.

The lower insulating layer 103 has a laminated structure made of Al ₂ O ₃ and SiN _x . Al ₂ O ₃ is Al ₂ O
Si in ₃ atmospheres using Ar target
N _x is formed by RF (high frequency) sputtering in a mixed gas of Ar and N ₂ (nitrogen) using a Si target.

Then, the light emitting layer 104 is formed on the lower insulating layer 103.
Are laminated and formed. The light emitting layer 104 can be formed of a thin film type light emitting layer or a powder type light emitting layer in which a phosphor material is dispersed in a dielectric.

First, the thin film type light emitting layer will be described.

The thin-film type light emitting layer is made of ZnS which is the base material.
Mn (manganese), which is the emission center material, is added to (zinc sulfide)
It is made of ZnS: Mn added by 0.5 wt%, the substrate temperature is set at 300 ° C. to 500 ° C., and a film is formed by the EB vapor deposition method. The emission wavelength is 585 nm of yellow-orange.

As the material of the light emitting layer, in consideration of the photosensitivity wavelength dependence of the photoconductor layer 107 to be formed later, CaS (calcium sulfide) which is the base material and Eu (the light emission center material) in the red region are taken into consideration. Europium) -added CaS: E
u, ZnS: Tb obtained by adding Tb (terbium) to ZnS and F (fluorine) as a charge compensator in the green region,
F, SrS (strontium sulfide) in the blue region and C
SrS with e (cerium) and K (potassium) added:
Ce and K may be used.

Further, the light emitting layer is formed by the CVD method and the R method.
It is also possible to use the F sputtering method and the ALE (atomic layer epitaxy) method.

After that, in order to remove water or the like that causes deterioration of the light emitting layer, vacuum heat treatment is performed at 400 ° C. to 600 ° C. to form a thin film type light emitting layer.

Next, the powder type light emitting layer will be described.

In the powder type light emitting layer, as a light emitting layer material, ZnS which is a base material and Cu (copper) and C which are emission center materials are used.
ZnS: Cu, Cl added with 1 (chlorine) is used.
ZnS: Cu having a grain size of 5 μm to 20 μm,
Disperse phosphor material such as Cl in the dielectric,
The thickness is about 0 μm.

[0143] In powders light-emitting layer, the electric field intensity to be applied to the light-emitting layer is ^{1 × 10 4 V / cm~3 ×} 10 approximately ⁴ V / cm, since hardly dielectric breakdown of the light-emitting layer, the powder-type The light emitting layer 104 including the light emitting layer of the transparent electrode 106 and the back electrode 10
It can be formed by being directly sandwiched between the two. That is, in this case, the lower insulating layer 103 and the upper insulating layer 105 may not be formed.

The emission color obtained at this time is blue green when the emission center material is ZnS: Cu, Cl, ZnS: Cu,
Since Al is green and ZnS: Cu, Mn, and Cl are yellow-orange, the material can be selected according to the photosensitivity wavelength dependence of the photoconductor layer 107, as in the case of the thin film type light emitting layer. ..

The upper insulating layer 105 is formed on the light emitting layer 104 formed of the thin film type light emitting layer or the powder type light emitting layer thus formed.

The upper insulating layer 105 has a laminated structure made of SiO _x and SiN _x . SiO _x is Ar and O
_In a mixed gas of ₂ (oxygen), SiN _x is formed in a mixed gas of Ar and N ₂ by an RF sputtering method using a Si target.

The upper insulating layer 105 is made of SiO _x and SiN _x.
In addition, BaTa ₂ O ₆ (barium tantalate), Sr
TiO ₃ (strontium titanate), and Ta ₂ O ₅
(Tantalum oxide) or the like may be used.

After that, the glass substrate 101, the back electrode 102, the lower insulating layer 103, and the light emitting layer 104 are formed by RF sputtering.
The transparent electrode 106 is formed on almost the entire surface of the substrate including the upper insulating layer 105. The transparent electrode 106 is made of ITO.
To use.

According to such a structure, the light valve and the scanning optical signal source formed of the light emitting layer 104 can be driven completely independently by grounding the transparent electrode 106.

The light-emitting layer 104 of the EL element described above is driven by AC driving with a bipolar pulse.
It is also possible to provide a current limiting layer between the 104 and the back electrode 102 and perform direct current driving with a unipolar pulse. This current limiting layer is a thick film in which MnO ₂ (manganese dioxide) is dispersed in a binder resin, and the film thickness is 1 μm to
10 μm.

Next, a-Si: H is formed on the transparent electrode 106 as a photoconductor layer 107 for receiving the light from the light emitting layer 104 which is a scanning optical signal source by the plasma CVD method.

Bi ₁₂ SiO ₂₀ and Cd are used as the photoconductor layer 107 whose impedance changes according to the light irradiation amount.
S, a-SiC: H, a-SiO: H, and a-Si
N: H or the like can be used.

Next, a multilayer film formed by alternately stacking TiO ₂ and SiO ₂ as a dielectric mirror 109 is formed on the photoconductive layer 107 via the light shielding layer 108 by the EB vapor deposition method.

Photoconductor layer 107 through dielectric mirror 109
A light shielding layer 108 is formed between the dielectric mirror 109 and the photoconductor layer 107 in order to prevent the readout light 116 from leaking.

As the light-shielding layer 108, a carbon-dispersed organic thin film or Al ₂ O ₃ plated with CdTe and Ag electroless is used.
Etc. can be used.

On the back surface of the glass substrate 101, that is, the surface opposite to the surface on which the EL element is formed, a metal film 115 for blocking light from other than the EL element is provided.

The metal film 115 can be formed of Ag, Al, Mo or the like. Further, a pigment-dispersed light-shielding film used for a color filter of a liquid crystal panel is used as the metal film 11.
It is also possible to use instead of 5.

A glass substrate facing the glass substrate 101
A data transmission electrode 112 is formed on 113, and the data transmission electrode 112 is formed by patterning ITO deposited by a sputtering method in a stripe shape.

Dielectric mirror 109 and data transmission electrode 112
Then, a polyimide film is applied by spin coating and baked to form alignment films 110a and 110b, respectively, and the surfaces of the alignment films 110a and 110b are subjected to a molecular alignment treatment by rubbing.

The glass substrates 101 and 113 on which the alignment films 110a and 110b are respectively formed are arranged so that the data transmission electrodes 112 and the light emitting layer 104 which is a scanning optical signal source are vertically crossed. A liquid crystal layer 111 is formed by bonding the substrates through a spacer (not shown), injecting liquid crystal between both substrates, and sealing with a sealant 114.

The liquid crystal forming the liquid crystal layer 111 has a larger impedance than the impedance of the photoconductor layer 107 selected as a scanning line by light irradiation, and compared with the impedance of the photoconductor layer 107 not selected. Select a liquid crystal that becomes smaller.

The glass substrates 101 and 103 are examples of the first and second substrates of the present invention. The light emitting layer 104 is an example of the optical waveguide of the present invention. Photoconductor layer 107 is an example of the photoconductor layer of the present invention. The liquid crystal layer 111 is an example of the liquid crystal layer of the present invention.

In the liquid crystal light valve having the above structure, the impedance of the photoconductor layer 107 selected as the scanning line by light irradiation is much smaller than the impedance of the liquid crystal layer 111, so that it is applied between the electrodes. Most of the data signals are applied to the liquid crystal layer 111. However, the data signal is not applied to the liquid crystal layer 111 because the impedance of the photoconductor layer 107 which is not irradiated with light becomes larger than the impedance of the liquid crystal layer 111.

FIG. 10 is a schematic block diagram of the drive portion of the liquid crystal light valve 100 of the fifth embodiment shown in FIGS. 8 and 9.
For simplification, the signal and timing generator are not shown in the figure.

As shown in the figure, the drive unit of the liquid crystal light valve 100 shown in FIGS. 8 and 9 includes a driver array 121 for driving EL elements for scanning signals and a liquid crystal light valve.
And a drive circuit 122 for driving the data transmission electrode 112 included in 100.

The structure of the projection type image display device using the liquid crystal light valve 100 and the operation mode of the liquid crystal layer are the same as the structure and operation mode of the liquid crystal layer shown in FIG.

Therefore, according to this embodiment, similarly to the liquid crystal light valve according to the first embodiment, it is possible to form a high-contrast image and to realize the miniaturization of the device.

Furthermore, it is not necessary to connect a light emitting element array such as an LED array, and a high level technique such as alignment is not required.

Furthermore, the liquid crystal light valve 100 of this embodiment
It is also possible to apply to a two-dimensional optical operation element by providing polarizing plates in a crossed Nicols state on both surfaces of the above and using a ferroelectric liquid crystal having a memory property in the liquid crystal layer 111 of the liquid crystal light valve 100.

Next, a sixth embodiment of the present invention will be described.

FIG. 11 is a sectional view showing the schematic construction of the sixth embodiment of the liquid crystal light valve according to the present invention.

As shown in the figure, the liquid crystal light valve 200 of this embodiment includes optical waveguides 201 and 202 and a first substrate 20.
3, the second substrate 204, the cladding layer 205, the transparent electrode 206,
Adhesive resin 207, metal film 208, photoconductor layer 209, light shielding layer 21
0, a dielectric mirror 211, a glass substrate 212, a data signal electrode 213, alignment films 214a and 214b, and a liquid crystal layer 215.

In the liquid crystal light valve 200 of this embodiment,
As an optical signal for scanning, the leakage of light transmitted along the optical waveguides 201 and 202 is used.

First, a method of manufacturing the optical waveguides 201 and 202 will be described.

To form the optical waveguide 201, the first substrate 20
A groove for an optical waveguide is formed on the surface 3 by using a wet etching method.

That is, a resist is applied to both surfaces of the first substrate 203, pre-baked, and then exposed, developed, and post-baked to form a mask for forming a groove on one surface.

Then, etching with buffered hydrofluoric acid and resist stripping are performed to form stripe-shaped grooves.

In addition to this wet etching method,
Grooves can be formed by dry etching such as sputter etching using Ar gas, argon ion beam etching, and other mechanical polishing.

For the optical waveguide 201, a polyimide having excellent heat resistance is used among polymer materials which can be easily photolithographically processed. Polyimide is used because the substrate temperature is about 300 ° C. when the photoconductor layer 209 is formed by the plasma CVD method.

First substrate 203 having a groove formed on one surface
After the polyimide is diluted with a solvent and applied with a spinner, heat treatment is performed. A resist is applied thereon, and a mask is formed by pre-baking, exposure, development, and post-baking so as to cover the groove portion formed in the first substrate 203. afterwards,
The optical waveguide 201 is formed by performing etching of polyimide, stripping of resist, and final heat treatment.

For the etching of polyimide, a wet etching method using a hydrazine / hydrate type etchant is used.

In this embodiment, the non-photosensitive polyimide is used, but if the photosensitive polyimide is used, the optical waveguide can be formed in a smaller number of steps.

Further, as will be described later, since polyimide having a refractive index larger than that of the first substrate 203 made of a fiber plate is selected, it is not necessary to provide a clad layer on the substrate side.

On the other hand, a transparent electrode 206 made of ITO is provided on the optical waveguide 201, but since the refractive index of the transparent electrode 206 is larger than that of the optical waveguide 201, it is necessary to provide the cladding layer 205. .. The cladding layer 205 is formed by sputtering using SiO ₂ which is a low refractive index dielectric.

As another method of forming the clad layer 205, a polyimide having a smaller refractive index than the polyimide used as the optical waveguide 201 can be used to form the clad layer 205.

In this case, the cladding layer 205 is the optical waveguide 201.
The light propagating through the layer must be formed so as to cause appropriate leakage, and the thickness of the cladding layer is 50 angstroms to 5000 angstroms.
The Angstrom range is suitable. The thickness of the cladding layer 205 in this example is about 3000 Angstroms.

When the optical waveguide 202 is formed on the second substrate 204, the first substrate 203, the second substrate 204 and the optical waveguide 20 are formed.
2 It is necessary to consider the matching of the refractive indexes of the adhesive resin 207 and the adhesive resin 207.

That is, since light leaks from the optical waveguide 202 and passes through the first substrate 203, the refractive index of the optical waveguide 202 and the refractive index of the first substrate 203 are substantially equal to each other, or the first substrate 203. The index of refraction of 203 must be greater than the index of refraction of the optical waveguide 202. The refractive index of the second substrate 204 is the optical waveguide.
It must be less than the index of refraction of 202.

To satisfy these conditions, for example, the first substrate 203 is made of a fiber plate having a refractive index of about 1.53, and the second substrate 204 is made of quartz having a refractive index of about 1.457.
For the optical waveguide 202, polyimide having a refractive index of about 1.53 may be selected. Since the adhesive resin 207 also serves as the cladding layer of the optical waveguide 202, a resin having a refractive index of about 1.48 may be selected.

In this case, the optical waveguide 201 can be made of polyimide having a refractive index of about 1.61.

The widths of the optical waveguides 201 and 202 are equal to each other, and the optical waveguides 201 are adjacent to each other.
The intervals of 201 are formed to be twice the width of each of the optical waveguides 201. Similarly, in the optical waveguide 202, the interval between the optical waveguides 202 adjacent to each other is 2 times the width of each of the optical waveguides 202.
It is formed to double. The optical waveguide 201 and the optical waveguide 202 are formed in parallel with each other and shifted by 1/2 pitch.

A reactive ion etching (RIE) method is effective for forming the groove of the second substrate 204 made of quartz. Other CF ₄ as the reactive gas also, CF ₄
And H ₂ mixed gas, CF ₄ and C ₂ H ₄ mixed gas,
C ₂ F ₅ , a mixed gas of C ₂ F ₆ and C ₂ H ₄ , C
₃ F ₈ , a mixed gas of C ₃ F ₈ and C ₂ H ₄ , CHF ₃ ,
And C ₄ F ₈ can be used. Further, the groove can be formed by sputter etching using Ar gas, argon ion beam etching, or other mechanical polishing.

The method of forming the optical waveguide 202 is the same as the case of forming the optical waveguide 201 described above.

The back surface of the second substrate 204, that is, the optical waveguide 202.
A metal film 208 for blocking light from other than the optical waveguide is provided on the surface opposite to the surface on which is formed.

The metal film 208 can be formed of Ag, Al, Mo or the like. In addition, a pigment-dispersed light-shielding film used for a color filter of a liquid crystal panel is used as the metal film 20.
It is also possible to use instead of 8.

Next, a method of forming each layer above the cladding layer 205 in FIG. 11 will be described.

A transparent electrode 206 made of ITO is formed on the clad layer 205 by a sputtering method. Transparent electrode 20
On the substrate 6, a-Si: H is formed as a photoconductor layer 209 for receiving the light from the optical waveguide 201 by the plasma CVD method.

Bi ₁₂ SiO ₂₀ and Cd are used as the photoconductor layer 209 whose impedance changes according to the irradiation amount of light.
S, a-SiC: H, a-SiO: H, and a-Si
N: H or the like can be used.

Then, a light shielding layer 210 is formed on the photoconductor layer 209.
Through TiO ₂ and SiO ₂ as a dielectric mirror 211.
A multilayer film formed by alternately stacking and is formed by the EB vapor deposition method.

Photoconductor layer 209 through dielectric mirror 211
In order to prevent the read light 216 from leaking, a light shielding layer 210 is formed between the dielectric mirror 211 and the photoconductor layer 209.

The light-shielding layer 210 is made of a carbon-dispersed organic thin film or Al ₂ O ₃ plated with CdTe and Ag electroless.
Etc. can be used.

A glass substrate facing the first substrate 203
A data transmission electrode 213 is formed on 212. The data transmission electrode 213 is a transparent IT deposited by a sputtering method.
It is formed by patterning O in a stripe shape.

Dielectric mirror 211 and data transmission electrode 213
In the above, a polyimide film is applied by spin coating and baked to form alignment films 214a and 214b, respectively, and the surfaces of the alignment films 214a and 214b are subjected to a molecular alignment treatment by rubbing.

The first substrate 203 and the glass substrate 212 on which the alignment films 214a and 214b are respectively formed are arranged so that the data transmission electrode 213 and the scanning optical waveguide 201 are vertically crossed with each other. A liquid crystal layer 215 is formed by bonding through a spacer not shown and injecting liquid crystal between both substrates to seal the substrates.

Finally, the first substrate 203 made of a fiber plate having the optical waveguide 201 formed thereon is aligned with the second substrate 204 made of quartz having the optical waveguide 202 formed thereon, and bonded with the adhesive resin 207.

The liquid crystal forming the liquid crystal layer 215 has impedance higher than that of the photoconductor layer 209 selected as a scanning line by light irradiation, and higher than that of the photoconductor layer 209 not selected. Select a liquid crystal that becomes smaller.

The first substrate 203 and the second substrate 204 are examples of the two substrates included in the first substrate of the present invention. Glass substrate 212 is an example of the second substrate of the present invention. The optical waveguides 201 and 202 are the first and second embodiments of the present invention.
2 is an example of the optical waveguide of FIG. Photoconductor layer 209 is an example of the photoconductor layer of the present invention. The liquid crystal layer 215 is an example of the liquid crystal layer of the present invention.

In the liquid crystal light valve having the above structure, the impedance of the photoconductor layer 209 selected as a scanning line by light irradiation is much smaller than the impedance of the liquid crystal layer 215, so that it is applied between the electrodes. Most of the data signals are applied to the liquid crystal layer 215. However, since the impedance of the photoconductor layer 209 which is not irradiated with light becomes larger than the impedance of the liquid crystal layer 215, the data signal is not applied to the liquid crystal layer 215.

Therefore, according to this embodiment, similarly to the liquid crystal light valve according to the first embodiment, it is possible to form a high-contrast image and realize the miniaturization of the device.

Further, conventionally, since the optical waveguide was formed on one substrate, a gap was formed between the adjacent scanning lines, but according to this embodiment, the optical waveguide is formed on each of the two substrates. By doing so, it is possible to eliminate the gap between the scanning lines and increase the number of scanning lines. Thereby, the resolution and the aperture ratio can be improved.

When the first substrate 203 is made of glass, the optical signal leaked from the optical waveguide 202 spreads while passing through the first substrate 203, and the light amount decreases on the original scanning line. I will end up. Further, if an optical signal leaks to the adjacent scanning line, crosstalk will occur. In order to prevent these, the above-mentioned embodiment shows an example in which a fiber plate is used for the first substrate 203. By using the fiber plate, the optical signal from the optical waveguide 202 can be surely transmitted vertically upward (direction opposite to the traveling direction of the reading light 216 in FIG. 11) without lateral leakage.

FIG. 12 is a schematic block diagram of the drive portion of the liquid crystal light valve 200 of the sixth embodiment shown in FIG. For simplification, the signal and timing generator are not shown in the figure.

As shown in the figure, the drive unit of the liquid crystal light valve 200 of FIG. 11 includes an LED array 221 for scanning signals,
Data transmission electrodes included in the liquid crystal light valve 200
And a drive circuit 222 for driving 213.

A semiconductor laser array may be used instead of the LED array 221.

The LED array 221 is a liquid crystal light valve 200.
The light pulse signal emitted from the LED array 221 is led to the liquid crystal light valve 200.

FIG. 13 is a perspective view showing details of the connecting portion of the LED array 221 of FIG.

As shown in the figure, the LED array of FIG.
221 is composed of LED arrays 221a and 221b, and LE
The light emitted from each of the D arrays 221a and 221b is transmitted through the optical prisms 223a and 223b to the optical waveguides 225a and 225b.
Are each led to.

The optical waveguides 225a and 225b correspond to the optical waveguides 201 and 202 of the liquid crystal light valve 200 of FIG. 11, respectively.

That is, the LED array and the optical prism are
One set is provided for each of the upper scanning optical waveguide and the lower scanning optical waveguide. Note that in FIG. 13, the optical waveguide of the liquid crystal light valve 200 is shown for clarity.
Only the upper optical waveguide 225a and the lower optical waveguide 225b corresponding to 201 and the optical waveguide 202 are shown, and other components of the liquid crystal light valve are omitted.

Also, in this way, the optical prisms 223a and 223b are
Without using the optical waveguides 225a and 225a of the liquid crystal light valve 200.
The end faces of 25b and the light emitting faces of the LED arrays 221a and 221b may be directly coupled to each other.

The reflecting mirrors 224a and 224b are the optical waveguides 225a and
It is provided in order to reflect the light on each end face of 225b and to efficiently guide the light to the photoconductive layer of the liquid crystal light valve 200, and is made of Al, Ag or the like.

The structure of the projection type image display device using the liquid crystal light valve 200 and the operation mode of the liquid crystal layer are the same as those of the projection type image display device and the operation mode of the liquid crystal layer shown in FIG. The bulb 200 can be applied to a high contrast, high resolution projection imager.

Also, polarizing plates are provided on both sides of the liquid crystal light valve 200 of this embodiment in a crossed Nicol state, and a ferroelectric liquid crystal having a memory property is used for the liquid crystal layer 215 of the liquid crystal light valve 200, so that two-dimensional It can also be applied to an optical arithmetic element.

Next, a seventh embodiment of the present invention will be described.

FIG. 14 is a sectional view showing a schematic structure of a seventh embodiment of the liquid crystal light valve according to the present invention.

In the liquid crystal light valve of this embodiment, as shown in FIG.
In the liquid crystal light valve 200 of the sixth embodiment shown in FIG. 1, the lower optical waveguide 202, which is a scanning optical signal source, is formed of a light emitting layer composed of EL elements.

As shown in FIG. 14, the liquid crystal light valve 300 of this embodiment includes a fiber plate 301 and an optical waveguide 30.
2, back electrode 303, glass substrate 304, lower insulating layer 305,
Light emitting layer 306 composed of EL element, upper insulating layer 307, transparent electrode 308, adhesive resin 309, clad layer 310, transparent electrode 311
A metal film 312, a photoconductor layer 313, a light shielding layer 314, a dielectric mirror 315, a glass substrate 316, a data signal electrode 317, alignment films 318a and 318b, and a liquid crystal layer 319.

A method of manufacturing the liquid crystal light valve 300 will be described.

With the liquid crystal light valve 300 of this embodiment,
In order to obtain stable light emission from the EL element, a sandwich structure in which the light emitting layer 306 is sandwiched between the lower insulating layer 305 and the upper insulating layer 307 is used.

First, the back electrode 303 is formed on the glass substrate 304. Al is used for the back electrode 303, a film is formed by an EB vapor deposition method, and then an etching process is performed to perform patterning in a stripe shape.
Form 3 In addition to Al, Ti and Mo may be used for the back electrode 303.

Next, as an insulating layer for applying a stable high electric field to the light emitting layer 306 between the back electrode 303 and the transparent electrode 308, a lower insulating layer 305 is provided on the back electrode 303 side and an upper layer is provided on the transparent electrode 308 side. An insulating layer 307 is formed.

The lower insulating layer 305 has a laminated structure composed of Al ₂ O ₃ and SiN _x . Al ₂ O ₃ is Al ₂ O
Films of SiN _x are formed by RF sputtering in a mixed gas of Ar and N ₂ using a Si target in an Ar atmosphere using ₃ targets.

Then, a light emitting layer 306 made of an EL element is laminated and formed on the lower insulating layer 305. The light emitting layer 306 can be formed of a thin film type light emitting layer or a powder type light emitting layer in which a phosphor material is dispersed in a dielectric.
An upper insulating layer 307 is formed thereon.

The upper insulating layer 307 has a laminated structure made of SiO _x and SiN _x . SiO _x is formed in a mixed gas of Ar and O _2, and SiN _x is formed in a mixed gas of Ar and N ₂ by an RF sputtering method using a Si target.

SiO _X and SiN _X are formed on the upper insulating layer 307.
In addition to BaTa ₂ O ₆ , SrTiO ₆ and Ta ₂ O ₅
Etc. may be used.

After that, the transparent electrode 308 is formed on the upper insulating layer 307 by the RF sputtering method. Transparent electrode 308
Uses ITO as a material.

According to such a structure, the light valve and the scanning optical signal source formed of the light emitting layer 306 can be driven completely independently by grounding the transparent electrode 308.

Light-emitting layer 306 composed of EL element described above
Is driven by alternating current drive with bipolar pulse,
A current limiting layer is provided between the light emitting layer 306 and the back electrode 303,
It is also possible to carry out DC driving with a unipolar pulse. This current limiting layer is a thick film in which MnO ₂ is dispersed in a binder resin, and its thickness is set to 1 μm to 10 μm.

Next, a method of manufacturing the optical waveguide 302 will be described.

To form the optical waveguide 302, a groove for the optical waveguide is formed on the fiber plate 301 by a wet etching method.

That is, resist is applied to both surfaces of the fiber plate 301, pre-baked, and then exposed, developed, and post-baked to form a mask for forming a groove on one surface.

Then, etching with buffered hydrofluoric acid and resist stripping are performed to form stripe-shaped grooves.

In addition to this wet etching method,
Grooves can be formed by dry etching such as sputter etching using Ar gas, argon ion beam etching, and other mechanical polishing.

For the optical waveguide 302, polyimide, which is excellent in heat resistance, is used among polymer materials which can be easily processed by photolithography and molding. Polyimide is used because the substrate temperature is about 300 ° C. when the photoconductor layer 313 is formed by the plasma CVD method.

After the polyimide is diluted with a solvent and applied with a spinner on the fiber plate 301 having grooves formed on one surface, heat treatment is performed. Apply a resist on it, and pre-bak, expose, develop, and post-bak the fiber plate 30
A mask is formed so as to cover the groove portion formed in 1.
After that, the optical waveguide 302 is formed by performing polyimide etching, resist stripping, and final heat treatment.

For etching polyimide, a wet etching method using a hydrazine / hydrate-based etchant is used.

In this embodiment, the non-photosensitive polyimide is used, but if the photosensitive polyimide is used, the optical waveguide can be formed in a smaller number of steps.

Since polyimide having a refractive index larger than that of the fiber plate 301 is selected, it is not necessary to provide a clad layer on the substrate side.

On the other hand, the transparent electrode 311 made of ITO is provided on the optical waveguide 302. However, since the refractive index of the transparent electrode 311 is larger than the refractive index of the optical waveguide 302, it is necessary to provide the cladding layer 310. .. The clad layer 310 is formed by a bias sputtering method using SiO ₂ which is a low refractive index dielectric.

As another method for forming the clad layer 310, a polyimide having a smaller refractive index than the polyimide used for the optical waveguide 302 can be used to form the clad layer 310. In this case, the clad layer 310 needs to be formed so that the light propagating through the optical waveguide 302 causes an appropriate leakage, and the thickness of the clad layer is preferably in the range of 50 angstroms to 5000 angstroms. The thickness of the cladding layer 310 in this example is about 3000 Angstroms.

Further, the width of the optical waveguide 302 is equal to the width of the back electrode 303, and the optical waveguide 302 and the back electrode 303 have the same spacing between the optical waveguides 302 adjacent to each other and the distance between the back electrodes 303 adjacent to each other. Is formed so as to have a width twice that of each. The optical waveguide 302 and the back electrode 303 are formed in parallel with each other with a 1/2 pitch shift.

The back surface of the glass substrate 304, that is, the back electrode 303.
A metal film 312 for blocking light from other than the optical waveguide is provided on the surface opposite to the surface on which is formed.

The metal film 312 can be formed of Ag, Al, Mo, or the like. Further, a pigment-dispersed light-shielding film used for a color filter of a liquid crystal panel is used as the metal film 31.
It can be used instead of 2.

Next, a method of forming each layer above the cladding layer 310 in FIG. 14 will be described.

A transparent electrode 311 made of ITO is formed on the clad layer 310 by a sputtering method. Transparent electrode 31
A-Si: H is formed on 1 as a photoconductor layer 313 for receiving light from the optical waveguide 302 by a plasma CVD method.

Bi ₁₂ SiO ₂₀ and Cd are used as the photoconductor layer 313 whose impedance changes according to the light irradiation amount.
S, a-SiC: H, a-SiO: H, and a-Si
N: H or the like can be used.

Then, a light shielding layer 314 is formed on the photoconductor layer 313.
Through TiO ₂ and SiO ₂ as a dielectric mirror 315.
A multilayer film formed by alternately stacking and is formed by the EB vapor deposition method.

Photoconductor layer 313 through dielectric mirror 315
In order to prevent the read light 320 from leaking, a light shielding layer 314 is formed between the dielectric mirror 315 and the photoconductor layer 313.

The light-shielding layer 314 is made of a carbon-dispersed organic thin film, or CdTe and Ag electroless plated Al ₂ O ₃ film.
Etc. can be used.

Data transmission electrodes 317 are formed on the glass substrate 316 facing the fiber plate 301. The data transmission electrode 317 is formed by patterning transparent ITO deposited by a sputtering method in a stripe shape.

Dielectric mirror 315 and data transmission electrode 317
In and, a polyimide film is applied by spin coating and baked to form alignment films 318a and 318b, respectively, and the surfaces of the alignment films 318a and 318b are subjected to molecular alignment treatment by rubbing.

The fiber plate 301 and the glass substrate 316 on which the alignment films 318a and 318b are respectively formed are shown so that the data transmission electrode 317 and the scanning optical waveguide 302 are in a position in which they are vertically intersected with each other. A liquid crystal layer 319 is formed by bonding the substrates through a spacer that does not exist and injecting liquid crystal between both substrates to seal the substrates.

Finally, the glass substrate 304 having the light emitting layer 306 made of an EL element is aligned with the fiber plate 301 having the optical waveguide 302 formed thereon, and the glass substrate 304 is attached with the adhesive resin 309.

The liquid crystal forming the liquid crystal layer 319 has impedance higher than that of the photoconductor layer 313 selected as a scanning line by light irradiation, and higher than that of the photoconductor layer 313 not selected. Select a liquid crystal that becomes smaller.

Fiber plate 301 and glass substrate 304
Is an example of two substrates included in the first substrate of the present invention. Glass substrate 316 is an example of the second substrate of the present invention. The optical waveguide 302 and the light emitting layer 306 are examples of the first and second optical waveguides of the present invention. Photoconductor layer
313 is an embodiment of the photoconductor layer of the present invention. Liquid crystal layer 31
9 is an embodiment of the liquid crystal layer of the present invention.

In the liquid crystal light valve having the above-mentioned structure, the impedance of the photoconductor layer 313 selected as a scanning line by light irradiation is much smaller than the impedance of the liquid crystal layer 319, so that it is applied between the electrodes. Most of the data signals are applied to the liquid crystal layer 319. However, since the impedance of the photoconductor layer 313 not irradiated with light becomes larger than the impedance of the liquid crystal layer 319, the data signal is not applied to the liquid crystal layer 319.

Therefore, according to this embodiment, as with the liquid crystal light valve according to the first embodiment, it is possible to obtain a high-contrast image and realize the miniaturization of the device.

Further, conventionally, since the optical waveguide is formed on one substrate, a gap is formed between the adjacent scanning lines. However, according to this embodiment, the stripe-shaped optical waveguide and the scanning line for the scanning lines are formed. Since the light emitting layers composed of EL elements are used in combination, it is possible to eliminate the gap between the scanning lines and increase the number of scanning lines. Thereby, the resolution and the aperture ratio can be improved.

When the substrate corresponding to the fiber plate 301 is formed of glass, the optical signal from the light emitting layer 306 spreads while passing through this glass substrate, and the light amount decreases on the original scanning line. Further, if an optical signal leaks to the adjacent scanning line, crosstalk will occur. In order to prevent these, in the above-described embodiment, the fiber plate 301
Therefore, the optical signal from the light emitting layer 306 is surely vertically upward without leaking laterally (reading light 320 in FIG.
(The direction opposite to the traveling direction of).

In the above-mentioned embodiment, the lower optical waveguide which is the scanning optical signal source is constituted by the light emitting layer 306 which is composed of the EL element, but the upper optical waveguide 302 which is also the scanning optical signal source is the EL element. It may be configured from
Further, both the upper and lower optical waveguides may be composed of EL elements. Even if these configurations are adopted, there is no problem in operation.

In this embodiment, the stripe-shaped collision excitation type EL element is used for the scanning line, but an injection type EL element may be used. This injection type EL
As the element, for example, p having a-SiC: H as a light emitting layer is used.
An in element or the like can be used.

The structure of the projection type image display device using the liquid crystal light valve 300 and the operation mode of the liquid crystal layer are the same as those of the projection type image display device and the operation mode of the liquid crystal layer shown in FIG. The bulb 300 can be applied to a high contrast, high resolution projection imager.

Also, polarizing plates are provided on both surfaces of the liquid crystal light valve 300 of this embodiment in a crossed Nicol state, and a ferroelectric liquid crystal having a memory property is used for the liquid crystal layer 319 of the liquid crystal light valve 300, so that two-dimensional It can also be applied to an optical arithmetic element.

[0274]

As described above, according to the present invention, a liquid crystal layer provided between a first substrate and a second substrate each having a transparent electrode, a liquid crystal layer and a first substrate are provided. And a photoconductor layer whose impedance changes depending on the incident light, and an optical waveguide which irradiates the photoconductor layer with light from the first substrate side. Since the liquid crystal is driven by using the optical scanning signal as described above, a high-contrast image can be formed. Further, since a writing light source such as a CRT or a liquid crystal panel is not required, the device can be downsized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a first embodiment of a liquid crystal light valve according to the present invention.

FIG. 2 is a schematic configuration diagram of a drive unit of the liquid crystal light valve shown in FIG.

FIG. 3 is a perspective view showing details of a connecting portion of the LED array in FIG.

FIG. 4 is a schematic configuration diagram showing an embodiment of a device when the liquid crystal light valve shown in FIG. 1 is applied to a projection type image display device.

FIG. 5 is a sectional view showing a schematic configuration of a second embodiment of the liquid crystal light valve according to the present invention.

FIG. 6 is a cross-sectional view of a substrate on which an optical waveguide and an LED portion included in a liquid crystal light valve according to a third embodiment of the present invention are formed.

FIG. 7 is a cross-sectional view showing a schematic configuration of a liquid crystal light valve according to a fourth embodiment of the present invention.

FIG. 8 is a perspective view showing a schematic configuration of a fifth embodiment of a liquid crystal light valve according to the present invention.

9 is a cross-sectional view taken along the line AA of FIG.

10 is a schematic configuration diagram of a driving unit of the liquid crystal light valve shown in FIGS. 8 and 9. FIG.

FIG. 11 is a sectional view showing a schematic configuration of a sixth embodiment of the liquid crystal light valve according to the present invention.

12 is a schematic configuration diagram of a drive unit of the liquid crystal light valve shown in FIG.

13 is a perspective view showing details of a connecting portion of the LED array of FIG.

FIG. 14 is a sectional view showing a schematic configuration of a seventh embodiment of the liquid crystal light valve according to the present invention.

FIG. 15 is a cross-sectional view showing a configuration of a conventional light irradiation address type liquid crystal light valve.

[Explanation of symbols]

10, 40, 71, 80, 100, 200, 300 Liquid crystal light valves 11, 41, 63, 81, 201, 202, 302 Optical waveguides 12a, 12b, 42a, 42b, 82a, 82b, 101, 113, 21
2, 304, 316 Glass substrate 13, 43, 83, 106, 206, 308, 311 Transparent electrode 14, 44, 84, 205, 310 Cladding layer 15, 45, 85, 115, 208, 312 Metal film 16, 46, 86, 107, 209, 313 Photoconductor layer 17, 47, 87, 109, 211, 315 Dielectric mirror 19, 49, 89, 112, 213, 317 Data transmission electrodes 20a, 20b, 50a, 50b, 90a, 90b, 110a, 110b, 21
4a, 214b, 318a, 318b Alignment film 21, 51, 91, 111, 215, 319 Liquid crystal layer 102, 303 Back electrode 103, 305 Lower insulating layer 104, 306 Light emitting layer 105, 307 Upper insulating layer 108, 210, 314 Light shielding Layer 114 Sealing material 203 First substrate 204 Second substrate 207, 309 Adhesive resin 301 Fiber plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihisa Hatano 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (8)

[Claims] 1. A liquid crystal layer provided between a first substrate and a second substrate each having a transparent electrode, and an incident light provided between the liquid crystal layer and the first substrate. A liquid crystal light valve, comprising: a photoconductor layer whose impedance is changed by the emitted light; and an optical waveguide for irradiating the photoconductor layer with light from the first substrate side. 2. The optical waveguide is formed in a stripe shape on the first substrate, and the transparent electrode formed on the second substrate is patterned in a stripe shape. Item 1. The liquid crystal light valve according to item 1. 3. The liquid crystal light valve according to claim 2, wherein the transparent electrode formed on the first substrate is formed in a stripe shape parallel to the optical waveguide. 4. The liquid crystal light valve according to claim 1, wherein the optical waveguide is formed of a polymer waveguide. 5. The liquid crystal light valve according to claim 1, wherein the optical waveguide is formed of an electroluminescence element. 6. The first substrate includes two substrates, and the optical waveguide is formed on one of the two substrates and the other of the two substrates. A second optical waveguide is included, and the second optical waveguide is included.
Liquid crystal light valve described in. 7. The liquid crystal light valve according to claim 6, wherein a substrate formed on the liquid crystal layer side of the two substrates is formed of a fiber plate. 8. The liquid crystal light valve according to claim 6, wherein at least one optical waveguide of the first optical waveguide and the second optical waveguide is formed of an electroluminescence element.