JP3149257B2 - Imaging device having phthalocyanine photoconductive layer and imaging device using the imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a phthalocyanine photoconductive layer and a liquid crystal layer provided between electrode substrates, in which liquid crystal molecules are uniformly aligned, and an optically written image is incident on the phthalocyanine photoconductive layer. The present invention relates to an image pickup device that extracts the pixel-by-pixel impedance between electrodes generated when liquid crystal molecules are rearranged as a time-series electric signal corresponding to the optically written image, and a configuration of an image pickup device using the image pickup device.

[0002]

2. Description of the Related Art Conventionally, an image pickup device can be roughly classified into an image pickup tube and a solid-state image pickup device. The image pickup tube can be classified into a photoelectric surface type and a photoconductive surface type. The photocathode-type image pickup tube charges a photocharge on the surface of the photocathode corresponding to the brightness of the image when an optical writing image is incident on the photocathode, scans the photocharge with an electron beam, and outputs the photocharge. Take out the signal. In addition, the photoconductive surface type image pickup tube generates an electric charge on the surface of the photoconductive surface corresponding to the brightness of the image when the light writing image is incident on the photoconductive surface, and scans the electric charge with an electron beam. To obtain an output signal. On the other hand, in the solid-state imaging device, each pixel is formed independently and independently, and is divided into an XY address system and a charge transfer system. In the XY addressing method, an optical signal generated in each pixel is sequentially scanned and discharged to extract an output signal. In the charge transfer method, an output signal is obtained by sequentially transferring photocharges in a solid.

[0003]

However, in the above-described conventional image pickup apparatus using the image pickup tube or the image pickup device,
The configuration of the device became complicated. In particular, in the case of capturing an infrared image, the imaging tube has been generally used in the past. However, the infrared imaging tube itself is expensive, and the driving voltage is considerably high, so that it is difficult to realize a complete LSI of the driving circuit. There is a problem that it cannot be driven by a dry battery or a solar battery because of relatively large power consumption. In recent years, an optical writing element having an inorganic photoconductive layer called a liquid crystal light valve is sometimes used, but in general, the specific resistance of the liquid crystal is very large, and the dark resistance is about the same as the specific resistance of the liquid crystal. Photoconductive materials were limited. For example, indium stibium (InSb), lead selenide (PbSe), gallium arsenide (GaAs), gallium phosphide (GaP), indium arsenide (InAs), cadmium telluride (CdTe), cadmium mercury telluride (HgCdTe), amorphous selenium (A-S
e) An inorganic photoconductive substance such as amorphous silicon (a-Si) is a material having a low dark resistance or a functionally satisfactory one such that a desired wavelength sensitivity cannot be obtained. was there. For this reason, in the security system for the home, by detecting the infrared rays emitted from the human body or fire, simply have been used include the only sound the alarm. However, there is a strong demand for visualizing an infrared image, and development of a simple and inexpensive infrared imaging device and device has been desired. Furthermore, from the aspect of monitoring a visitor or building a centralized crime prevention management system in the living room, the captured infrared image can be reproduced at another place on the premises or at a remote place, and it can be driven by dry batteries or solar cells with low power consumption. The development of imaging devices has long been desired.

[0004]

Therefore, in the present invention, a phthalocyanine photoconductive layer and a liquid crystal layer are provided between electrode substrates to uniformly arrange liquid crystal molecules in an initial state. The liquid crystal molecule arrangement rearranges when a low-frequency voltage is applied, but is invented by paying attention to the basic property of not rearranging when a high-frequency voltage is applied. ,
An optical image is incident on the phthalocyanine photoconductive layer and a low frequency voltage is applied to rearrange the liquid crystal molecules. next,
In the case of reading an optical image, when an electrode is sequentially scanned and a high-frequency voltage is applied, an image sensor capable of outputting a time-series electrical signal of pixel-by-pixel impedance generated by rearrangement of liquid crystal molecules as an electric signal. An object of the present invention is to propose a structure and a structure of an image pickup apparatus using the image pickup device, and to solve the above-mentioned conventional drawbacks and requirements at once.

[0005] The present invention has been made based on the above-mentioned findings, and an image pickup device according to the first invention has a plurality of strip-shaped electrodes, and a pair of transparent electrode substrates formed by making the electrodes orthogonal and opposed to each other. A phthalocyanine photoconductive layer is provided on at least one inward surface of the electrode substrate, and a liquid crystal layer is sandwiched between the electrode substrates and liquid crystal molecules are uniformly arranged in the initial state, so that the photoconductive layer Light writing image is incident on
The pixel-based impedance between the electrodes generated when the liquid crystal molecules are rearranged is output as an electric signal, and the imaging device according to the second aspect of the present invention is configured such that the phthalocyanine photoconductive layer has at least the A slit is formed except for a portion corresponding to an electrode. The imaging device according to a third aspect of the present invention includes the imaging device and a low-frequency voltage for writing a light image to the imaging device. When,
A voltage generator for outputting a high frequency voltage for reading a written optical image, and a frequency switching circuit for appropriately switching and outputting the low frequency voltage and the high frequency voltage. Wherein the imaging device of the fourth invention outputs the imaging device, a low-frequency voltage for writing an optical image to the imaging device, and a high-frequency voltage for reading the written optical image. A voltage generator, a frequency switching circuit for appropriately switching and outputting the low-frequency voltage and the high-frequency voltage, and a frequency converter for displaying an output signal read from the image sensor in addition to another liquid crystal display device for display. Characterized by the following.

[0006]

The image sensor according to the present invention comprises a first strip electrode elongated in one direction, a phthalocyanine photoconductive layer, a liquid crystal layer, and a second strip electrode orthogonal to the first transparent electrode. ing. Now, when an optically written image is incident on the phthalocyanine photoconductive layer, the specific resistance of the photoconductive layer changes according to the brightness of the optical image. Here, when the liquid crystal molecules are initially arranged and a low-frequency voltage is applied between the first transparent electrode and the second transparent electrode, light is not emitted at the pixel portions where the transparent electrodes cross each other. Since the specific resistance of the photoconductive layer changes according to the brightness of the image, the liquid crystal molecules rearrange. By providing a slit (groove) in at least a portion of the phthalocyanine photoconductive layer where no electrode is present to reduce the lateral conductivity of the photoconductive layer, the resolution of a written optical image can be improved. Can be.

Liquid crystal molecules have anisotropy in which the dielectric constant in the major axis direction of the molecule and the dielectric constant in the minor axis direction are different from each other.
That is, the impedance significantly changes. Further, the liquid crystal molecule arrangement does not change with respect to the high frequency voltage. Therefore, the first transparent electrode and second transparent electrode are sequentially scanned, when applying a high frequency voltage, the output of the inter-electrode Inpi over dance of each pixel without affecting the alignment of liquid crystal molecules as an electric signal of time series And an electrical signal corresponding to the optically written image is obtained. Therefore, when this electric signal is introduced into a separate display device, the read light image can be reproduced and displayed. However, since the time-series electric signal contains a high-frequency component, the time-series signal cannot be displayed on any liquid crystal display device as it is. Therefore, when this time-series electric signal is converted into a low-frequency time-series signal via a frequency converter, the read light image is reproduced by a liquid crystal display device provided at an arbitrary place,
Can be displayed.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an image pickup device according to the present invention; FIG. 1 is a cross-sectional view schematically showing one embodiment of the image sensor according to the present invention, and FIG. 2 is an exploded perspective view schematically showing an embodiment of the image sensor according to the present invention. 1 and 2, an image pickup device 1 according to the present invention includes transparent electrode substrates 2a, 2a and 2b.
b are arranged at equal intervals and in parallel, a plurality of transparent strip electrodes 3a are provided on the inward surface of the electrode substrate 2a, and a plurality of transparent strip electrodes 3b are provided on the inward surface of the electrode substrate 2b. . Here, a transparent glass plate or a plastic plate is used as the electrode substrates 2a and 2b. The strip electrodes 3a and 3b are formed of an indium oxide film, a tin oxide film, or the like. The electrode substrates 2a and 2b are arranged at equal intervals and in parallel, and the distance between the electrode substrates 2a and 2b is determined by predetermined spacers 4a, 4b. In general, the interval between the electrode substrates 2a and 2b is 5 to 3
It is set in the range of 0 μm. Further, on the inward surface of the electrode substrate 2a provided with the band-shaped electrode 3a, a phthalocyanine photoconductive layer 5 whose specific resistance changes with the light intensity of the incident light 8 in a specific wavelength region is provided. In the present embodiment, the phthalocyanine photoconductive layer 5 is provided on the strip electrode 3a. However, the disposition position of the phthalocyanine photoconductive layer 5 is not necessarily limited, and the phthalocyanine photoconductive layer 5 may be provided on the strip electrode 3b. Good. An alignment layer 6a of liquid crystal molecules is applied on the phthalocyanine photoconductive layer 5, and an alignment layer 6b of liquid crystal molecules is applied on the inward surface of the electrode substrate 2b provided with the strip electrodes 3b.
The liquid crystal layer 7 is sandwiched between a and 6b.

In the image pickup device 1 according to the present invention, the photoconductive layer 5 is required to have a condition that the dark resistance of the photoconductive layer is equal to or higher than the specific resistance of the liquid crystal. Recently, high-purity liquid crystal materials have been used, and the specific resistance of liquid crystals has been improved, so that materials having a density of 10 ¹³ Ω · cm are not rare. Therefore, in this embodiment, the phthalocyanine photoconductive layer 5 is used. The phthalocyanine photoconductive layer 5 has a dark resistance of about 10 ¹⁴ Ω · cm. The phthalocyanine photoconductive layer 5
Is usually prepared by dispersing phthalocyanine in an organic solvent and adding a binder to the solution.
b to form a film. At this time, if the strip electrode 3a or the strip electrode 3b is not in ohmic contact, the phthalocyanine photoconductive layer 5 cannot obtain sufficient photoconductive properties with respect to an incident light image. As a result, an ohmic contact is obtained, and a photoresistance of about 10 ⁵ Ω · cm is obtained. The maximum wavelength sensitivity of the phthalocyanine photoconductive layer 5 usually stops at about 870 nm as shown in FIG. 4, but it is possible to extend the maximum wavelength sensitivity to around 1250 nm by adding an appropriate amount of a sensitizer in a long wavelength region. it can. FIG. 4 shows the relative change in the specific resistance of the general phthalocyanine photoconductive layer 5 having a thickness of about 50 μm with respect to the incident wavelength. As described above, the phthalocyanine photoconductive layer 5 has a sufficiently high dark resistance when no light image is incident, and almost no electric field is applied to the liquid crystal layer 7.
The liquid crystal molecules can maintain the initial alignment. Further, when an optical image is incident, the light resistance is sufficiently reduced.
The phthalocyanine photoconductive layer 5 and the liquid crystal material have very good compatibility because a high electric field acts on the liquid crystal molecules to rearrange the liquid crystal molecules. When the resolution of the written optical image 8 is reduced due to the lateral conductivity of the phthalocyanine photoconductive layer 5, the phthalocyanine photoconductive layer 5 is removed except for at least the portions corresponding to the strip electrodes 3a and 3b. When the slits (grooves) 51a and 51b are formed on the substrate, the resolution can be improved.

The phthalocyanine used in the present invention is a metal phthalocyanine such as titanyl phthalocyanine, vanadyl phthalocyanine, chloroaluminum phthalocyanine, copper phthalocyanine, or a non-metal phthalocyanine. Examples of the resin for dispersing the phthalocyanine pigment include thermoplastic resins such as polyvinyl chloride, polystyrene, polyacrylate, polymethacrylate, polyvinyl butyral, and polycarbonate; epoxy resins; thermosetting resins such as melamine resins; and ultraviolet curable or electron beams. Curable resin can be used. The phthalocyanine photoconductive layer, after dispersing the phthalocyanine in the resin solution,
It is prepared by applying to a support by a method such as dipping, spin coating, roll coating, spray coating, wire bar coating and the like.

The phthalocyanine photoconductive layer of the present invention was prepared in the following manner. 5 g of titanyl phthalocyanine 5 g of polyvinyl butyral (Eslec BMS manufactured by Sekisui Chemical) 5 g of 70 g of dichloroethane The above mixture was dispersed with glass beads for 1 hour using a paint conditioner to obtain a coating liquid. Next, this coating solution was applied on a transparent electrode, dried at 50 ° C. for 10 minutes, and dried at room temperature for 5 hours to obtain a photoconductive layer having a thickness of 10 μm. Note that it is preferable to provide an anisotropic conductive insulating film between the two to protect the phthalocyanine photoconductive layer from the liquid crystal layer.

As the alignment layers 6a and 6b, an alignment layer of liquid crystal molecules often used in a conventional liquid crystal display element can be used, and which liquid crystal material and how to align is selected. This determines the alignment material and the alignment processing method. Generally, when aligning liquid crystal molecules perpendicularly to the electrode substrate, it is only necessary to apply an aligning agent such as lecithin or chromium myristate complex. When the liquid crystal molecules are aligned in parallel with the electrode substrate, a rubbing treatment is performed after an alignment agent such as a polyimide or a chromium brasilate complex is applied. On the other hand, as a liquid crystal material of the liquid crystal layer 7, a nematic liquid crystal, a smectic liquid crystal, or the like can be used. Generally, a liquid crystal material such as a fluorine-based, Schiff-based, azoxy-based, ester-based, biphenyl-based, terphenyl-based, cyclohexane-based, pyrimidine-based, or dioxane-based liquid crystal material is used alone or in combination. In addition, a small amount of a chiral substance may be added in order to stably arrange liquid crystal molecules, and a small amount of a dye may be added in order to improve visibility.

Next, the operation principle of the image sensor according to the present invention will be described. Referring to FIG. 3, an operation for writing an optical image will be described first. The strip electrodes 3a, 3b are connected to an external power source (not shown), and all the strip electrodes 3a, 3b
, A frequency of about 16 to 64 Hz and a voltage of about 3 to 50 V are applied. Then, when an optical writing image 8 of a subject (not shown) enters the phthalocyanine photoconductive layer 5,
The specific resistance of the phthalocyanine photoconductive layer 5 decreases in the bright part of the light image 8, and does not change in the dark part of the light image 8. Therefore, in a bright portion of the optically written image 8, a high electric field acts on the liquid crystal layer 7, and the liquid crystal molecules are rearranged. However, since an electric field is hardly applied to the liquid crystal layer 7 in the dark portion of the light image 8, the liquid crystal molecules remain in the initial alignment and do not rearrange. Then, the portion where the liquid crystal molecules are rearranged and the portion where the liquid crystal molecules are not rearranged have a band-like electrode
A large difference occurs between the impedance values a and 3b.

This phenomenon will be described in detail with reference to FIGS. FIG. 5 shows an equivalent circuit of one pixel in the image sensor 1 according to the present embodiment, and the phthalocyanine photoconductive layer 5, the alignment layer 6a, the liquid crystal layer 7, and the like between the strip electrodes 3a and 3b connected to the external power supply. This shows that each impedance of the alignment layer 6b is interposed in series. FIG. 6 illustrates an example of a change in impedance of one pixel with respect to the intensity of incident light of the image sensor 1 according to the present embodiment. That is, FIG. 6 shows the phthalocyanine photoconductive layer 5, the alignment layer 6a, the liquid crystal layer 7, and the alignment layer 6b.
The left side of the horizontal axis indicates the change in the total sum of the capacitances when the light intensity of the light image 8 is weak and the liquid crystal molecules substantially maintain the initial alignment state. The sum of the capacitance when the light intensity is strong and the liquid crystal molecules are sufficiently rearranged is shown. From this figure, it can be seen that when the light intensity of the light image 8 changes, the capacitance changes by 15 nF or more. Note that the impedance characteristic curve in FIG. 6 is an example when the thickness of the liquid crystal layer 7 is 10 μm and the biphenyl-based liquid crystal is vertically aligned first. Further, when the optical image 8 is written on the phthalocyanine photoconductive layer 5, if the resolution of the optical image 8 is reduced due to the lateral conductivity of the photoconductive layer 5, at least the strip electrodes 3a and 3b are supported. The slits (grooves) 51a and 51b are formed in the phthalocyanine photoconductive layer 5 except for the portions to be formed, so that the resolution can be improved. In this case, after the phthalocyanine photoconductive layer 5 is formed, the slit can be formed by etching the photoconductive layer 5 except at least portions corresponding to the strip electrodes 3a and 3b. In addition, if the space between the slits is filled with an insulating resin or the like to increase the electrical insulation in the lateral direction of the photoconductive layer 5, higher resolution can be obtained. Also,
Instead of providing slits, at least strip electrodes 3a, 3b
The resolution can be improved even if the surface of the phthalocyanine photoconductive layer 5 is black-masked except for the portion corresponding to the above, and the specific resistance of the photoconductive layer 5 is not reduced in the masked portion.

Next, a case where an optical image is read will be described. The aforementioned low-frequency voltage is intermittently cut off. And
When the band-shaped electrodes 3a and 3b are sequentially scanned while a low-frequency voltage is not applied, a high-frequency voltage having a frequency of about 10 to 100 kHz is applied. It can be output as a signal. After the reading of the written optical image 8 is completed, a low-frequency voltage is applied again to all the strip electrodes 3a and 3b, and the optical image 8 is written. Here, the liquid crystal molecule arrangement has a basic property of rearranging when a low frequency voltage is applied, but not rearranging when a high frequency voltage is applied. The present invention is characterized by skillfully utilizing the basic properties of the liquid crystal. That is, in the present invention, when reading the optical image 8 written on the image sensor 1,
Using a high-frequency voltage that does not deform the liquid crystal molecule arrangement of the liquid crystal layer 7, only the capacitance for each pixel is detected and output. Therefore, the output time-series signal includes
Since the image information for each pixel is included, the time-series signals are not shown in a separate display device such as a liquid crystal display device, a cathode ray tube (CRT), or a plasma display device (PD).
When input to P) or the like, the optically written image 8 can be reproduced and displayed. Since the specific resistance of the photoconductive layer 5 and the alignment state of the liquid crystal molecules are reversibly changed in the image sensor 1 in accordance with the brightness of the writing image 8, the writing light image 8 disappears or a new light image 8 is formed. When writing, no erase signal is required.

Next, an example of an image pickup apparatus using the image pickup device 1 according to the present invention will be described. FIG. 7 shows a block diagram of this imaging device. In this example, a low frequency voltage of 32 Hz was used to write an optical image, and a high frequency voltage of 46 kHz was used to read a written optical image. Therefore, the imaging apparatus includes a voltage generator 11 including the generator 111 that outputs the low-frequency voltage of 32 Hz and the generator 112 that outputs the high-frequency voltage of 46 kHz.
Electric valves 12 to 14, inverter 15, counter 16
And a frequency switching circuit 18 having a built-in flip-flop circuit 17, a decoder circuit 19 and driver circuits 20 to 21 for driving the image sensor 1 of the present invention, a frequency converter 22, and another It is constituted by the decoder circuit 23 of the display device 30.

First, a case where an optical image is written to the image pickup device 1 will be described. The low frequency voltage of 32 Hz output from the oscillator 111 is applied to the electric valve 12. Here, when a negative pulse voltage is applied to the inverter 15 via the counter 16 and the flip-flop circuit 17, the electric valve 12 is turned on, and 32H output from the low-frequency voltage generator 111 is output.
The low frequency voltage of z is introduced to a decoder circuit 19 for driving the image sensor 1 of the present invention. Then, the decoder circuit 19 applies a control pulse to the driver circuits 20 and 21 for simultaneously selecting all of the strip electrodes 3a and 3b of the image sensor 1, and as a result, a low frequency voltage of 32 Hz is applied to all of the strip electrodes 3a and 3b of the image sensor 1. Is applied to Therefore, since the imaging device 1 is statically driven when an optical image is written, it operates sufficiently with a low driving voltage, and the response speed when the liquid crystal molecules are rearranged is fast.

Next, the case where the optical image written in the image sensor 1 is read will be described. When a positive pulse voltage is applied intermittently to the electric valves 13 and 14 via the counter 16 and the flip-flop circuit 17, the electric valves 13 and 14
14 becomes conductive, and the high-frequency voltage of 46 kHz output from the high-frequency voltage generator 112 is input to the decoder circuit 19 for driving the imaging device 1 of the present invention. The decoder circuit 19 applies control pulses for sequentially scanning the strip electrodes 3a and 3b of the image sensor 1 to the driver circuits 20 and 21.
As a result, a high-frequency voltage of 46 kHz is sequentially applied to the strip electrodes 3a and 3b, and current is supplied according to the magnitude of the impedance of each pixel. This 46 kHz high frequency current is
It can be extracted as a time-series signal including image information for each pixel, and the time-series signal is output via the electric valve 14. Therefore, when this time-series signal is introduced into the separate display device 30, the optical image written in the image sensor 1 can be reproduced and displayed. The configuration of the matrix electrode including the strip electrodes 3a and 3b in the imaging device 1 is as follows.
It is indispensable to output the image information written in the image sensor 1 as a time-series signal. However, when the separate display device 30 is a liquid crystal display device, the liquid crystal does not respond to a time-series signal of 46 kHz. Therefore, when reproducing using a liquid crystal display device, the time series signal output through the electric valve 14 is
And converts the signal into a low-frequency time-series signal having a frequency of about 16 to 64 Hz, and then introduces the signal into a decoder circuit 23 of a separate liquid crystal display device 30 surrounded by a broken line.

As described above in detail, the image pickup device and the image pickup apparatus of the present invention are driven statically when writing an optical image, and therefore have a lower cost than a conventional multiplex-driven simple matrix type liquid crystal display device. It operates satisfactorily with the driving voltage, and has a relatively high response speed when the liquid crystal molecules rearrange. In the imaging device of this embodiment, when the written optical image is not directly viewed, the optical anisotropy of the liquid crystal material does not matter and the liquid crystal molecules can be simply viewed in the major axis direction and the minor axis direction. A liquid crystal material having as large a dielectric anisotropy as possible can be used, and a sufficiently high response speed can be achieved at a sufficiently low operating voltage. Further, the capacitance characteristics shown in FIG. 6 can be improved.

The inorganic photoconductive material which has been widely used in the past has had many unsolved problems such as a material having a low dark resistance or a desired wavelength sensitivity cannot be obtained. Since the phthalocyanine photoconductive layer is used in the image sensor of the present invention, the dark resistance is sufficiently high when no light image is incident, and almost no electric field is applied to the liquid crystal layer. In addition, when an optical image is incident, the optical resistance is sufficiently reduced, and a high electric field acts on the liquid crystal layer, so that the liquid crystal molecules can be rearranged, thereby solving the conventional problems at once.

The present invention is not limited by the above-described embodiments, such as the method of forming the photoconductive layer, the shape of the electrodes, the alignment material and initial alignment of liquid crystal molecules, and the liquid crystal material.
As long as the change in impedance between the electrodes with respect to the writing light image is large and the change in impedance can be efficiently extracted as a time-series signal, it is, of course, possible to appropriately change the embodiment. It does not change the philosophy in any way.

[0022]

According to the image pickup device and the image pickup apparatus of the present invention,
Since a phthalocyanine photoconductive layer is used, when an optical image is not incident, a dark resistance of about 10 ¹⁴ Ω · cm is obtained, which is sufficiently high, and almost no electric field is applied to the liquid crystal layer. When an optical image is incident, the optical resistance is 10 ⁵ Ω ·
cm, a high electric field acts on the liquid crystal layer to allow the liquid crystal molecules to be rearranged, so that the optical writing characteristics are significantly improved as compared with the inorganic photoconductive layer which has been frequently used in the past. In addition, the liquid crystal molecules are uniformly arrayed, and static driving is performed when an optical image is written, and multiplexing driving is performed when a written optical image is read. Things. In addition, in order to perform static driving when writing an optical image, it operates sufficiently at a lower driving voltage compared to a conventional multiplex driving type simple matrix type liquid crystal display element, and has a response speed when liquid crystal molecules are rearranged. Is relatively fast. Further, in the image pickup device of the present embodiment, the written optical image is not directly visually recognized, so that the optical anisotropy of the liquid crystal material does not matter,
A liquid crystal material having a relatively large dielectric anisotropy in the major axis direction and the minor axis direction of the liquid crystal molecules can simply be used, and a sufficiently high response speed can be achieved with a sufficiently low operating voltage.

When reading out the written optical image, the electrodes of the matrix structure are sequentially scanned and a high-frequency voltage is applied to change the impedance of each pixel without changing the liquid crystal molecular arrangement. Since it is output as a series signal, it can be read by simply scanning the matrix electrode once. The time required for this is extremely short, and the optical image can always be tracked even when the optically written image moves or changes. The operation function in this point is completely different from that of the conventional multiplex driving type simple matrix type liquid crystal display device, and therefore, the present invention has a specific operation and effect. Further, since the structure is extremely simple, it can be manufactured at low cost and high reliability can be expected. Power consumption is also low. Therefore, the imaging device of the present invention can be driven by an appropriate battery or a solar cell.

Incidentally, in a conventional image pickup apparatus using an image pickup tube or an image pickup device, the structure of the apparatus has become complicated. In particular,
In the case of capturing an infrared image, the image pickup tube has been generally used in the past. However, the infrared image pickup tube itself is expensive, and the driving voltage is considerably high, so that it is difficult to realize a complete LSI of the drive circuit, and power consumption is low. However, there were drawbacks such as the inability to be driven by a battery or a solar cell because of the relatively large number. Further, there is no solid-state imaging device that captures an infrared image. Compared with such a conventional image pickup tube or image pickup device, the image pickup device and the image pickup apparatus of the present invention can perform low-voltage / low-power-consumption operation, low-cost, high reliability, and infrared image pickup as described above. Therefore, it can be widely introduced into general home security systems, and has a great effect on security such as crime prevention and fire.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one embodiment of an image sensor according to the present invention.

FIG. 2 is an exploded perspective view schematically showing one embodiment of the image sensor according to the present invention.

FIG. 3 is a cross-sectional view schematically showing the operation of the imaging device according to the present invention.

FIG. 4 is a characteristic diagram showing an example of the spectral sensitivity of the image sensor according to the present invention.

FIG. 5 is an equivalent circuit diagram of one pixel of the image sensor according to the present invention.

FIG. 6 is a characteristic diagram showing an example of a change in impedance of one pixel of the image sensor according to the present invention.

FIG. 7 is a block diagram showing an embodiment of an imaging device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image sensor 2a Electrode substrate 2b Electrode substrate 3a Strip electrode 3b Strip electrode 5 Phthalocyanine photoconductive layer 51a Slit 51b Slit 6a Liquid crystal molecule alignment layer 6b Liquid crystal molecule alignment layer 7 Liquid crystal layer 8 Optical writing image 11 Voltage generator 18 Frequency switching circuit 22 Frequency converter

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuhiro Yamamoto 2-28-4 Tomigaya, Shibuya-ku, Tokyo Inside Tokai University (56) References JP-A-59-216126 (JP, A) 1-319734 (JP, A) Patent 2666953 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01J 1/00-1/60 G02F 1/13 H01L 31/08

Claims (4)

(57) [Claims] 1. A plurality of strip-shaped electrodes, comprising a pair of transparent electrode substrates, wherein said electrodes are orthogonal and opposed to each other, and a phthalocyanine photoconductive layer is provided on at least one inward surface of said electrode substrate. A liquid crystal layer is sandwiched between the electrode substrates and liquid crystal molecules are uniformly arranged in the initial stage, and an optically written image is incident on the phthalocyanine photoconductive layer,
An image sensor, wherein the pixel-by-pixel impedance between the electrodes generated when the liquid crystal molecules are rearranged is output as an electric signal of a light image. 2. The imaging device according to claim 1, wherein a slit is formed in the phthalocyanine photoconductive layer except at least a portion corresponding to the electrode. 3. A plurality of strip-shaped electrodes, comprising a pair of transparent electrode substrates, wherein the electrodes are orthogonal and opposed to each other, and a phthalocyanine photoconductive layer is provided on at least one inward surface of the electrode substrates. A liquid crystal layer was sandwiched between the electrode substrates and the liquid crystal molecules were uniformly aligned, and an optical writing image was incident on the phthalocyanine photoconductive layer, and the liquid crystal molecules were rearranged. An image sensor that outputs the pixel-by-pixel impedance between the electrodes as an electrical signal of an optical image, a low-frequency voltage for writing an optical image to the image sensor, and a pixel-by-pixel impedance between the electrodes that are extracted as an electrical signal. An imaging apparatus comprising: a voltage generator that outputs a high frequency voltage; and a frequency switching circuit that appropriately switches and outputs the low frequency voltage and the high frequency voltage. 4. A plurality of strip-shaped electrodes, comprising a pair of transparent electrode substrates having the electrodes orthogonal and opposed to each other, a phthalocyanine photoconductive layer provided on at least one inward surface of the electrode substrates, A liquid crystal layer was sandwiched between the electrode substrates and the liquid crystal molecules were uniformly aligned, and an optical writing image was incident on the phthalocyanine photoconductive layer, and the liquid crystal molecules were rearranged. An image sensor that outputs the pixel-by-pixel impedance between the electrodes as an electrical signal of an optical image, a low-frequency voltage for writing an optical image to the image sensor, and a pixel-by-pixel impedance between the electrodes that are extracted as an electrical signal. A voltage generator that outputs a high-frequency voltage, a frequency switching circuit that appropriately switches and outputs the low-frequency voltage and the high-frequency voltage, and an output signal that is read from the image sensor. An imaging device comprising: a liquid crystal display device; and a frequency converter for display.