JP2003037258A - Photodetector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce decline in image quality due to scattering of recording light made incident on the inside of an electrostatic recording body. SOLUTION: A due absorbing read light is contained in a blocking layer 7 of an electrostatic recording body 10, composed by arraying in the order a recording light side conductive layer 1 transmissive for the recording light, a recording light conductive layer 2 presenting conductivity, by receiving irradiation of the recording light transmitted through the recording light side conductive layer 1, a charge transport layer 3 acting substantially as an insulator for electric charges charged to the recording light side conductive layer 1 and acting substantially as a conductor for the electric charges of the reverse polarity of the latent electric charges, a reading light conductive layer 4 presenting the conductivity by receiving the irradiation of the read light, the blocking layer 7 and a reading light side conductive layer 5 transmissive for the reading light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photodetector equipped with an electrostatic recording body capable of recording image information as an electrostatic latent image.

[0002]

2. Description of the Related Art Conventionally, in medical X-ray photography,
In order to reduce the exposure dose to the subject and to improve the diagnostic performance, a photoconductor such as a selenium plate made of a-Se (amorphous selenium), which is sensitive to radiation such as X-rays, is used as an electrostatic recording medium. The electrostatic recording body is irradiated with recording radiation (recording light) such as X-rays carrying the radiation image information to accumulate latent image charges carrying the radiation image information in the electricity storage section of the electrostatic recording body, After that, by scanning the electrostatic recording medium with a reading electromagnetic wave (reading light) such as a laser beam, a current generated in the electrostatic recording medium is detected through flat plate electrodes or stripe electrodes on both sides of the electrostatic recording medium. Due to
A system for reading an electrostatic latent image carried by a latent image charge, that is, a radiation image information is known (for example, Japanese Laid-Open Patent Publication No.
No. 00-105297, the same 2000-284056.
No.

Here, the above-mentioned Japanese Patent Laid-Open No. 2000-
The electrostatic recording body described in Japanese Laid-Open Patent Publication No. 105297 and the like receives a recording light side conductive layer (first conductive layer) that is transparent to recording light, and is irradiated with recording light transmitted through the recording light side conductive layer. By doing so, it acts as a substantially insulator against the latent image charge of the same polarity as the charge charged in the recording photoconductive layer and the recording light side conductive layer which generate electric charge and exhibit conductivity, and the latent image charge A charge transport layer that acts substantially as a conductor with respect to the transport polarity charge (transport charge) having a polarity opposite to that of the above, a reading photoconductive layer that exhibits electrical conductivity by generating a charge when irradiated with a reading light, and a reading light A reading light-side conductive layer (second conductive layer) having transparency to is laminated in this order, and a power storage unit is formed at the interface between the recording photoconductive layer and the charge transport layer.

In the above electrostatic recording body, the reading light side conductive layer may be a flat plate electrode transparent to the reading light, or a large number of light irradiations transparent to the reading light may be irradiated. It is also possible to provide a striped electrode composed of a linear electrode for use.

Further, the applicant of the present invention discloses the above-mentioned Japanese Patent Laid-Open No. 2000-28.
No. 4056, etc., in order to improve the reading efficiency, a charging linear electrode (charge extracting linear electrode) is arranged in parallel with a linear electrode for light irradiation forming a stripe electrode in a conductive layer on the reading light side. Then, a detector is proposed in which the charging linear electrode can be used when an electric signal corresponding to the amount of latent image charge accumulated in the power storage unit is output.

When the charging linear electrode is thus provided, a new capacitor is formed between the power storage unit and each charging linear electrode, and has a polarity opposite to the latent image charge accumulated in the power storage unit by recording. It is possible to charge the transporting polar charges also on the charging linear electrode by the charge rearrangement at the time of reading. As a result, the amount of the transport charge distributed to the capacitor formed between the light irradiation linear electrode and the power storage unit via the reading photoconductive layer is more relative to that in the case where the charging linear electrode is not provided. In addition to improving the reading efficiency by increasing the amount of signal charge that can be taken out from the detector to the outside, it is also possible to achieve compatibility with the effects of providing the stripe electrode, such as high-speed read response. Is able to.

Furthermore, the applicant of the present invention has disclosed the above-mentioned Japanese Patent Laid-Open No. 2000-1.
In Japanese Patent No. 05297, etc., as one of the methods for reading the latent image charge accumulated in the electrostatic recording body, a detection amplifier is connected to each light irradiation linear electrode forming a stripe electrode,
The longitudinal direction of the linear electrode is the sub-scanning direction, and the direction orthogonal to the longitudinal direction of the linear electrode is the main scanning direction (line electrode arrangement direction), and the linear reading light extends in the main scanning direction. It has been proposed to scan the stripe electrode side in the sub-scanning direction (hereinafter also referred to as line light) to detect the signal charge for each light irradiation linear electrode (hereinafter referred to as line reading method).

In this line reading system, parallel (simultaneous) reading is performed in the main scanning direction, so that the reading speed can be increased, and the electrodes are divided into the linear electrodes for light irradiation so that each detection amplifier can be read. Since the distribution capacity (load capacity) of is reduced, the S / N ratio can be improved, and furthermore, the latent image charge storage position can be fixed at the position where the linear electrode for light irradiation is arranged. It is an excellent method having various advantages such as enabling noise correction.

[0009]

However, when the latent image charge is read from the electrostatic recording body by the above-mentioned line reading method, when the line light is scanned in the sub-scanning direction, it passes through the light irradiation linear electrode. The reading light that has entered the electrostatic recording medium is scattered before it reaches the reading light incident surface of the reading photoconductive layer, and the scattered reading light is used to irradiate the reading light incident surface of the reading photoconductive layer. When reaching the area adjacent to the linear electrode in the longitudinal direction, electric discharge is generated there and the sharpness of the read image in the longitudinal direction of the electrode is reduced.

Further, in the case of reading the latent image charge by the above-mentioned line reading method from the electrostatic recording body provided with the charging linear electrode described in Japanese Patent Laid-Open No. 2000-284056, it is used for light irradiation. The reading light that has passed through the linear electrodes and entered the electrostatic recording medium is scattered before reaching the reading light incident surface of the reading photoconductive layer, and the scattered reading light enters the reading photoconductive layer. When the area corresponding to the charging linear electrode adjacent to the light-irradiating linear electrode on the surface is reached, discharge is generated there and the signal detection efficiency is reduced, so that the image quality of the read image is reduced.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a photodetector capable of reducing deterioration in image quality caused by scattering of recording light incident on an electrostatic recording body. It is intended.

[0012]

A first photo-detecting device according to the present invention is a first conductive layer which is transparent to recording light, and a recording which exhibits photoconductivity by being irradiated with the recording light. For use as a latent image charge, a reading photoconductive layer that exhibits photoconductivity by being irradiated with reading light, and a reading photoconductive layer. In a photodetector including an electrostatic recording body, a second conductive layer having a large number of light-transmitting linear electrodes that are transparent to each other are stacked in this order. An absorption unit that absorbs the reading light is provided between the irradiation linear electrode and the irradiation linear electrode.

A second photodetector according to the present invention is
A first conductive layer that is transparent to recording light, a recording photoconductive layer that exhibits photoconductivity when irradiated with recording light, and a latent image charge that has an amount of charge according to the amount of recording light. Storage unit, a photoconductive layer for reading that exhibits photoconductivity by being irradiated with reading light, a large number of linear electrodes for light irradiation that are transparent to the reading light, and a large number of charging electrodes. A photodetector provided with an electrostatic recording body comprising a linear electrode and a second conductive layer in which a linear electrode for light irradiation and a linear electrode for charging are alternately arranged in this order. In the third aspect, an absorption unit that absorbs the reading light is provided between the reading photoconductive layer and the second conductive layer.

Here, the "absorption means for absorbing the reading light" means that the reading light, that is, the electromagnetic wave for reading, which has entered the electrostatic recording medium, is absorbed by a predetermined amount, and passes through the linear electrode for light irradiation. This is to reduce the amount of the incident reading light reaching the adjacent pixels in the longitudinal direction of the light irradiation linear electrode and the adjacent charging linear electrode, and does not completely absorb the reading light. For example, it means that the incident reading light is transmitted by a predetermined amount, such as absorbing 50% and transmitting the remaining 50%.

The "electrostatic recording medium" is the first conductive layer,
A photoconductive layer for recording, a photoconductive layer for reading, and a second conductive layer are provided in this order, and a power storage unit is formed between the photoconductive layer for recording and the photoconductive layer for reading. Further, it may be formed by stacking other layers or micro conductive members (micro plates). The electrostatic recording body also includes recording light for carrying image information, that is, electromagnetic waves for recording (not limited to visible light, but also includes radiation transmitted through an object, radiation carrying radiation image information, etc.). Anything can be used as long as it can record image information as an electrostatic latent image by irradiation.

The "light-irradiating linear electrode having transparency to the reading light" is an electrode which transmits the reading light and generates charge pairs in the reading photoconductive layer. Further, the "charging linear electrode" is an electrode for outputting an electric signal of a level according to the amount of latent image charge accumulated in the power storage unit,
It is desirable to have a light-shielding property with respect to the reading light. However, when a light-shielding film having a light-shielding property is provided between the charging linear electrode and the reading light irradiation means, the charging linear electrode does not necessarily have the light-shielding property. You don't have to have one. Here, the “light-shielding property” is not limited to the one that completely blocks the reading light and does not generate the charge pair at all, and the charge pair generated by the reading light even if it has some transparency to the reading light. Including items that do not pose a problem. Therefore, all the charge pairs generated in the reading photoconductive layer are not limited to only the reading light transmitted through the light irradiation linear electrode, and the reading light may be generated even if the reading light slightly transmitted through the charging linear electrode. It is assumed that charge pairs can be generated in the conductive layer.

Further, the "reading light" may be any light as long as it can move the charge in the electrostatic recording medium and electrically read the electrostatic latent image. Specifically, the reading light is light or radiation. Etc.

In the first and second photodetectors according to the present invention, the absorbing means emits the reading light by scattered light of the reading light by ηr, the discharge efficiency of the linear electrode for light irradiation in the reading light irradiation region by the reading light. When the discharge efficiency of the linear electrode for light irradiation in the area for one pixel next to the area is ηrn, the conditional expression ηr It is preferable that / ηrn ≧ 2 is satisfied.

In addition, in the second photodetector according to the present invention, the absorbing means includes the light irradiation linear electrode and the charging linear electrode which are adjacent to each other, and the light irradiation line in the reading light irradiation region by the reading light. When the discharge efficiency of the linear electrode is ηr and the discharge efficiency of the charging linear electrode due to scattered light in the reading light irradiation region by the reading light is ηs, the conditional expression ηr / Ηs
It is desirable that ≧ 2 is satisfied.

Further, in the first and second photo-detecting devices according to the present invention, between the reading photoconductive layer and the light irradiation linear electrode, and between the light irradiation linear electrode and the charging linear electrode. A blocking layer that is transparent to the reading light and has blocking performance against charge injection from the light irradiation linear electrode and the charging linear electrode may be provided between the two. May be a dye that is contained in the blocking layer and absorbs the reading light.

Here, the "blocking layer" may cover the upper surface of each linear electrode (each linear electrode for light irradiation or each linear electrode for light irradiation and charging), or each linear electrode. It may cover the entire surface (top surface and side surface) of the electrode. In addition, a blocking layer may be formed on the upper surface of the support between the linear electrodes. Also,
The material of the blocking layer on the upper surface and the material of the blocking layer on the side surface of each linear electrode is not particularly required to be the same, and any material may be used as long as it has blocking performance. Therefore, for example, the upper surface of each linear electrode may be blocked with a predetermined material, and the side surface of each linear electrode may be blocked with a different material.

In addition to having blocking ability, this blocking layer has a buffering property for alleviating thermal stress due to a difference in thermal expansion coefficient between the second conductive layer and the photoconductive layer for reading, and the second conductive layer. It is preferable that the layer has a function of suppressing crystallization at the interface with the reading photoconductive layer and strengthens the adhesion between the second conductive layer and the reading photoconductive layer.

[0023]

According to the first photo-detecting device of the present invention, the absorption means for absorbing the reading light is provided between the reading photoconductive layer and the light-irradiating linear electrode. The reading light that has passed through the linear electrodes and entered the electrostatic recording medium is scattered before reaching the reading light incident surface of the reading photoconductive layer, and the scattered reading light enters the reading photoconductive layer. It is possible to reduce a decrease in sharpness in the longitudinal direction of the linear electrode for light irradiation caused by reaching a region adjacent to the longitudinal direction of the linear electrode for light irradiation on the surface.

Further, in the second photodetector according to the present invention, the first photodetector is provided with the absorbing means for absorbing the read light between the read photoconductive layer and the light irradiation linear electrode. In addition to the same effect as the detection device, the reading light that has passed through the light irradiation linear electrode and enters the electrostatic recording body scatters before reaching the reading light incident surface of the reading photoconductive layer. When the read light reaches the area corresponding to the charging linear electrode adjacent to the light irradiation linear electrode on the reading light incident surface of the reading photoconductive layer, the detection signal is reduced, resulting in the image quality. Can be reduced.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a recording / reading system using an optical detection device according to a first embodiment of the present invention (an electrostatic latent image recording device and an electrostatic latent image reading device are integrated).
2 is a schematic configuration diagram of FIG.

This recording / reading system comprises an electrostatic recording body 10.
A recording light irradiation means 90, a power source 70, a current detection circuit 80 including a connection means S3 and a detection amplifier 81, and a reading light scanning means 93. The electrostatic latent image recording device portion is the electrostatic recording body 10. The recording light irradiation means 90 and a part of the current detection means 80 are provided, and the electrostatic latent image reading device part is composed of the electrostatic recording body 10, the reading light scanning means 93 and a part of the current detection means 80.

The electrostatic recording body 10 is irradiated with the recording light side conductive layer 1 which is transparent to the recording light (for example, radiation such as X-rays) and the recording light which has passed through the recording light side conductive layer 1. As a result, the recording photoconductive layer 2 and the recording light side conductive layer 1 which are electrically conductive act substantially as an insulator with respect to the charges (latent image charges) and have a polarity opposite to that of the latent image charges. A charge transport layer 3 that acts substantially as a conductor with respect to charges (transport polar charges), a reading photoconductive layer 4 that exhibits conductivity by being irradiated with reading light (for example, light in the blue region having a wavelength of 550 nm or less), The blocking layer 7 and the reading light side conductive layer 5 which is transparent to the reading light are arranged in this order. At the interface between the recording photoconductive layer 2 and the charge transport layer 3, a power storage unit 23 that accumulates latent image charges generated in the recording photoconductive layer 2 is formed.

Recording light side conductive layer 1 and reading light side conductive layer 5
As long as they are transparent to recording light or reading light, for example, both are Nesa film (SnO ₂ ), ITO (Indium Tin Oxide), or amorphous light transmissive material which is easy to etch. An oxide film such as IDIXO (Idemitsu Indium X-metal Oxide; Idemitsu Kosan Co., Ltd.) can be used with a thickness of 50 to 200 nm, for example.

When an image is recorded by using X-rays as the recording light and irradiating the X-rays from the recording light side conductive layer 1 side, it is not necessary to transmit visible light, so that the recording light side conductivity is not required. The layer 1 can also be made of, for example, 100 nm thick Al or Au.

On the other hand, the electrode of the reading light side conductive layer 5 is a stripe electrode 6 in which a large number of linear elements (light irradiation linear electrodes) 6a are arranged in a stripe pattern at a pixel pitch. In this case, the blocking layer 7 which is the next layer is immediately laminated without arranging an insulator between the respective elements, and the reading light side conductive layer 5 is constituted only by the stripe electrodes 6.

Here, the purpose of using the electrodes of the reading light side conductive layer 5 as the stripe electrodes 6 is to improve the S / N ratio of the image by simplifying correction of structure noise and reducing the capacitance, as described later. Or the electrostatic latent image is localized corresponding to the stripe electrodes to increase the electric field strength and improve the reading efficiency to improve the S / N ratio, or perform parallel reading (mainly in the main scanning direction). For example, the read time is shortened.

The recording photoconductive layer 2 may be any one as long as it exhibits conductivity when irradiated with recording light.
For example, lead oxides such as a-Se, PbO, and PbI ₂ (I
I), lead (II) iodide, Bi ₁₂ (Ge, Si)
A photoconductive substance containing at least one of O ₂₀ , Bi ₂ I ₃ / organic polymer nanocomposite as a main component is suitable, and among them, the quantum efficiency of radiation is relatively high and the dark resistance is high. Since a-Se is superior in terms of the above, a-Se is used.

The thickness of the recording photoconductive layer 2 containing a-Se as a main component is preferably 50 μm or more and 1000 μm or less so that the recording light can be sufficiently absorbed.

As the charge transport layer 3, the recording light side conductive layer 1 is used.
The larger the difference between the mobility of the negative charge that is charged in the negative direction and the mobility of the positive charge that has the opposite polarity, the better (for example, 10 ² or more, preferably 10 ³ or more), and poly N-vinylcarbazole (PVK), N , N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine (TPD), organic compounds such as discotic liquid crystal, or TPD Polymer (polycarbonate, polystyrene, PUK) dispersion, Cl 10-200-pp
Semiconductor materials such as m-doped a-Se are suitable.
In particular, organic compounds (PVK, TPD, discotic liquid crystal, etc.) are preferable because they have light insensitivity.
Since the dielectric constant is generally small, the capacities of the charge transport layer 3 and the reading photoconductive layer 4 are small, and the signal extraction efficiency during reading can be increased. It should be noted that "having light insensitivity" means that it exhibits almost no conductivity even when irradiated with recording light or reading light.

Further, for example, if the charge mobility in the vertical direction of the film thickness is larger than the charge mobility in the horizontal direction of the film thickness, the transport polar charge can move at a high speed in the thickness direction and in the lateral direction. Since the charge transport layer that does not easily move can be formed, the sharpness can be improved. Specific materials include discotic liquid crystal, hexapentyloxytriphenylene (Physica
l Review LETTERS 70.4, 1933)), the central core is π
A discotic liquid crystal group containing a conjugated fused ring or a transition metal (see EKISHO VOL No. 1 1997 P55) and the like are preferable.

The reading photoconductive layer 4 may be any one as long as it exhibits conductivity when irradiated with reading light.
For example, a-Se, Se-Te, Se-As-Te, metal-free phthalocyanine, metal phthalocyanine, MgPc.
(Magnesium phtalocyanine), VoPc (phaseII of
Vanadyl phthalocyanine), CuPc (Cupper phtaloc
A photoconductive substance containing at least one of yanine) as a main component is suitable.

The wavelength range from near ultraviolet to blue (300
To 550 nm) and low sensitivity to electromagnetic waves having a wavelength in the red region (700 nm or more), specifically, a-Se, PbI ₂ ,
Bi ₁₂ (Ge, Si) O _{2 0} , perylene bisimide (R = n-propyl), perylene bisimide (R = n-)
When a photoconductive substance containing at least one of neopentyl) as a main component is used, the read photoconductive layer 4 having a large bandgap and a small dark current due to heat can be formed. By scanning and exposing an electromagnetic wave having a wavelength in the range from ultraviolet to blue, noise due to dark current can be reduced.

The total thickness of the charge transport layer 3 and the reading photoconductive layer 4 is preferably 1/2 or less of the thickness of the recording photoconductive layer 2, and the thinner it is (eg, 1/1
Responsiveness at the time of reading is improved.

In particular, 0.05-0.5 μm thick a-Se
In that case, the dark resistance becomes very high, which is preferable. From the above, in the present embodiment, the reading photoconductive layer 4 is a-.
It is a layer containing Se as a main component and having a thickness of 0.05 to 0.5 μm.

As the blocking layer 7, for example, polyamide (polyamid) shown in US Pat. No. 4,535,468 is used.
e) or polyimide, or polyester, polyvinyl butyral, polyvinyl pyrrolidone, polyurethane, polymethylmethacrylate, polycarbonate, etc. A thin film of a volatile organic polymer can be used. In addition, the organic binder and about 0.3% to 3% weight ratio (by wei
It is also possible to use a thin layer of a mixed film made of a low molecular weight organic material such as nigrosine (ght). By providing the blocking layer 7, the positive charges charged in the reading light side conductive layer 5 are prevented from being injected into the reading photoconductive layer 4 due to the barrier potential, and noise due to direct injection of positive charges is eliminated. It becomes possible to prevent the occurrence.

Further, the material forming the blocking layer 7 contains a dye that absorbs the reading light. As described above, when light having a wavelength in the range of near-ultraviolet to blue is used as the reading light, the dye contained in the material forming the blocking layer 7 is, for example, a yellow dye which is a complementary color of blue. By incorporating this dye, the electrostatic recording body 10
The sharpness in the longitudinal direction of the element 6a caused by the reading light scattered inside reaches the area adjacent to the element (light irradiation linear electrode) 6a in the longitudinal direction on the reading light incident surface of the reading photoconductive layer 4. The decrease can be reduced. Here, the amount of the dye contained in the material forming the blocking layer 7 is ηr, which is the discharge efficiency of the element 6a in the reading light irradiation region by the reading light, and 1 pixel next to the reading light irradiation region by the reading light. Element 6a
, The conditional expression ηr / Ηrn
Adjust to satisfy ≧ 2.

Further, as is well known, an selenium film in an amorphous state is an interfacial crysta film at the interface with another metal during the vapor deposition process during film formation.
llization) progresses. The electrostatic recording body 10 of the present invention also
Since the reading photoconductive layer 4 is formed on the reading light side conductive layer 5, in the vapor deposition process of the reading photoconductive layer 4 and the subsequent vapor deposition of the charge transport layer 3, the recording photoconductive layer 2, etc., electrodes are formed. The interface crystallization proceeds at the interface between the material and a-Se, and the charge injection from the electrode increases, causing a problem of S / N reduction. When a transparent oxide film, especially ITO is used as the electrode material, the electrode material and a-Se are used.
Interfacial crystallization at the interface of (1) significantly progresses, and the S / N reduction becomes significant. However, by providing the blocking layer 7 made of an organic thin film between the reading light side conductive layer 5 and the reading photoconductive layer 4, the blocking layer 7 serves as a suppressing layer that suppresses interface crystallization of a-Se. It can function and can prevent direct contact between the electrode material of the reading light side conductive layer 5 and a-Se of the reading photoconductive layer 4, prevent chemical change of Se at the interface, and prevent interface crystallization. The effect of prevention is obtained. Therefore, the charge injection from the electrodes does not increase, and the problem of S / N reduction due to interface crystallization can be solved.

The thickness of the blocking layer 7 is 0.05.
Although it is preferable to set the thickness to about 5 μm, the range of 0.1 to 5 μm is preferable from the viewpoint of thermal stress buffering, while the range of 0.05 to 0.5 μm is preferable for good blocking performance without afterimage. On balance, 0.1-0.
The range is preferably 5 μm.

The current detection circuit 80 includes a conductive layer 5 on the reading light side.
A detection amplifier 81 connected to each element 6a is provided, and the recording light side conductive layer 1 of the electrostatic recording body 10 is connected to one input of the connecting means S3 and the negative electrode of the power supply 70. The positive electrode of 70 is connected to the other input of the connecting means S3. The output of the connecting means S3 is commonly connected to the non-inverting input terminal (+) of the operational amplifier 81a forming each detection amplifier 81. Each element 6a is
It is individually connected to the inverting input terminal (−) of the operational amplifier 81a. The detection amplifier 81 has a charge amplifier configuration including an operational amplifier 81a, an integrating capacitor 81c, and a switch 81d. The detection amplifier 81
May have a current-voltage conversion circuit configuration, for example.

The reading light scanning means 93 scans the reading light L2, which is substantially uniform in a line, in the longitudinal direction of the element 6a (in the direction of the arrow in the figure) while making the reading light L2 substantially orthogonal to the element 6a of the conductive layer 5 on the reading light side. To do. If the electrostatic recording body 10 having the stripe electrodes 6 is used, it is not necessary to scan with spot light such as a laser beam, so that the configuration of the scanning optical system can be made extremely simple and low cost.
Since an incoherent light source can be used, interference fringe noise can be prevented.

Further, between the electrostatic recording body 10 (reading light side conductive layer 5) and the reading light scanning means 93, the element 6a of the reading light L2 is provided at a portion corresponding to between the element 6a and the element 6a. A light-shielding film (not shown) made of a member having poor light transmittance is provided so that the irradiation intensity with the element 6a is lower than the irradiation intensity with the reading light L2 on the element 6a. As a result, the reading light L2
Will be irradiated only to the element 6a.

Next, a method of recording image information on the electrostatic recording body 10 as an electrostatic latent image and reading the recorded electrostatic latent image will be described. First, the process of recording an electrostatic latent image on the electrostatic recording body 10 will be described with reference to the cross-sectional view of the electrostatic recording body 10 shown in FIG.

First, a DC voltage is applied between the recording light side conductive layer 1 and each element 6a of the reading light side conductive layer 5 to charge both conductive layers. As a result, a U-shaped electric field is formed between the recording light side conductive layer 1 and the element 6a of the reading light side conductive layer 5, and most of the recording photoconductive layer 2 has a substantially parallel electric field. Exists, but there is a portion where no electric field exists at the interface between the photoconductive layer 2 and the charge transport layer 3 (FIG. 2A).
See Z). As the total thickness of the charge transport layer 3 and the reading photoconductive layer 4 is smaller than that of the recording photoconductive layer 2, and the ratio of the width of the elements 6a to the pitch is smaller (75% or less). If the thickness of the charge transport layer 3 and the reading photoconductive layer 4 is substantially equal to or smaller than the pitch of the elements 6a, such a portion where no electric field exists is formed more clearly. .

Next, the radiation L1 is uniformly emitted from the recording light irradiating means 90 toward the subject 9. The radiation L1 passes through the transmission part 9a of the subject 9 and further passes through the recording light side conductive layer 1. The recording photoconductive layer 2 receives the transmitted radiation L1.
(The radiation after this subject 9 becomes recording light),
Electrons (negative charges; latent image charges in this example) and holes (positive charges; transport polar charges in this example) according to the dose (light amount) of the radiation L1.
The electric charge pair is generated and becomes conductive.

The positive charges of the positive and negative charge pairs generated in the recording photoconductive layer 2 move in the photoconductive layer 2 toward the recording light side conductive layer 1 at high speed, and the recording light side conductive layer 1 And photoconductive layer 2
At the interface with and, the negative charges charged in the recording light side conductive layer 1 are recombined with the negative charges and disappear. On the other hand, the negative charges generated in the photoconductive layer 2 move toward the charge transfer layer 3 while being concentrated on the element 6a along the U-shaped electric field distribution (see FIG. 2B). The charge transfer layer 3 is the recording light side conductive layer 1
Since it acts as an insulator against a latent image charge (negative charge in this example) having the same polarity as that of the electric charge charged on the photoconductive layer 2, the negative charge that has moved through the photoconductive layer 2 is charged with the photoconductive layer 2. The electricity storage unit 23 formed at the interface with the transfer layer 3 stops, and the electrostatic latent image is recorded centering on the element 6a (see FIG. 2C). The amount of accumulated charges is determined by the amount of negative charges generated in the recording photoconductive layer 2, that is, the amount of the radiation L1 that has passed through the subject 9. Further, when the amount of the radiation L1 is small, the negative charges are attracted to the center of the element 6a and the accumulated charges are separated for each element 6a.
Element 6 because it can be accumulated together
By narrowing the pitch of a (pixel pitch), it is possible to record an electrostatic latent image with high sharpness (spatial resolution). Further, by concentrating the electric field on each element 6a, the reading efficiency can be improved and the S / N can be increased. In today's advanced semiconductor forming technology, it is easy to form the elements 6a at sufficiently narrow intervals, so that such an electrostatic recording body 10 can be easily manufactured. On the other hand, since the radiation L1 does not pass through the light blocking portion 9b of the subject 9, the portion below the light blocking portion 9b of the electrostatic recording body 10 does not change at all.

In this way, by irradiating the subject 9 with the radiation L1, charges corresponding to the subject image are formed at the interface between the recording photoconductive layer 2 and the charge transfer layer 3, and the electricity storage unit 2 is formed.
3 will be able to be accumulated. The subject image carried by the accumulated latent image charges is called an electrostatic latent image. As is clear from the above description, the configuration of the apparatus for recording an electrostatic latent image on the electrostatic recording body 10 according to the present invention is extremely simple, and the recording work is also extremely simple.

Next, the process of reading the electrostatic latent image recorded as described above will be described with reference to the cross-sectional view of the electrostatic recording body 10 shown in FIG.

When reading the electrostatic latent image, the connecting means S3
Is connected to the recording light side conductive layer 1 side of the electrostatic recording body 10 and both conductive layers 1 and 5 of the electrostatic recording body 10 are brought to the same potential through the imaginary short circuit of the operational amplifier 81a to rearrange the charges. . Next, the reading light scanning means 93 scans the element 6a with the linear reading light L2 in the longitudinal direction. The reading light L2 passes through the reading light side conductive layer 5, and the reading photoconductive layer 4 irradiated with the reading light L2 becomes conductive according to the scanning. This is because the recording photoconductive layer 2 has radiation L1.
Similarly to the case where the positive and negative charge pairs are generated by the irradiation with the light and the conductivity is exhibited, it depends on the generation of the positive and negative charge pairs upon the irradiation with the reading light L2.

The reading photoconductive layer 4 and the charge transport layer 3 are provided between the element 6a and the electricity storage unit 23 (an interface between the recording photoconductive layer 2 and the charge transport layer 3) in which latent image charges are accumulated. A very strong electric field (strong electric field) is formed according to the total thickness of the image and the amount of latent image charge. Here, since the charge transport layer 3 acts as a conductor with respect to transport polar charges (positive charges in this example), the positive charges generated in the reading photoconductive layer 4 are latent images in the power storage unit 23. It rapidly moves in the charge transport layer 3 so as to be attracted by electric charges, and recombines with the latent image charges in the electricity storage unit 23 to disappear. On the other hand, the negative charges generated in the reading photoconductive layer 4 are recombined with the positive charges of the reading light side conductive layer 5 and disappear. The photoconductive layer 4 is scanned by the reading light L2 with a sufficient light amount, and all the electrostatic latent images carried by the latent image charges accumulated in the power storage unit 23 are erased by charge recombination. In this way, the disappearance of the electric charges accumulated in the electrostatic recording body 10 means that the electrostatic recording body 10
It means that a current flows due to the movement of electric charges.

Further, the reading light L2 'which is scattered inside the element 6a and the blocking layer 7 and reaches the area adjacent to the reading light incident surface of the reading photoconductive layer 4 in the longitudinal direction of the element 6a, is read by the elements 6a and 6a. The inside of the blocking layer 7 containing a dye that absorbs the reading light L2 is longer than the reading light L2 that passes through the blocking layer 7 and reaches the reading light incident surface of the reading photoconductive layer 4 at a substantially shortest distance. Since it moves a distance, a larger amount of light is absorbed as compared with the reading light L2 that arrives at a substantially shortest distance. Therefore, it is possible to reduce a decrease in sharpness in the longitudinal direction of the element 6a due to light leakage to a region adjacent to the reading light incident surface of the reading photoconductive layer 4 in the longitudinal direction of the element 6a.

A current detection circuit 80 is connected to the electrostatic recording body 10. This current charges the integration capacitor 81c of the detection amplifier 81 connected to each element 6a, and the integration is performed according to the amount of current flowing. Capacitor 81c
The electric charge is accumulated in the capacitor and the voltage across the integrating capacitor 81c rises. Therefore, for each detection amplifier 81, the switch 81d is turned on between the pixels during scanning of the reading light L2 to discharge the electric charge accumulated in the integration capacitor 81c, so that both ends of the integration capacitor 81c are successively discharged. A change in voltage is observed corresponding to the accumulated charge of each pixel. Since the change in voltage corresponds to the charge accumulated in the electrostatic recording body 10 for each pixel, the electrostatic latent image can be read by detecting the change in voltage.

Next, a second embodiment of the recording / reading system using the photodetector according to the present invention will be described with reference to FIG. FIG. 4A is a perspective view of the electrostatic recording body 20,
FIG. 4B is an XZ sectional view of the Q arrow finger portion, and FIG. 4C is an XY sectional view of the P arrow finger portion.

This electrostatic recording body 20 comprises a recording light side conductive layer 2
1, recording photoconductive layer 22, charge transport layer 30, reading photoconductive layer 24, blocking layer 31, reading light side conductive layer 25
Are laminated in this order. The layers other than the reading light side conductive layer 25 are similar to those of the electrostatic recording body 10 according to the first embodiment.

The reading light side conductive layer 25 includes a stripe electrode 26 formed by arranging a large number of linear elements (light irradiation linear electrodes) 26a in a stripe pattern and a large number of linear elements (charging linear electrodes). ) 27a is arranged in a stripe pattern and a sub-stripe electrode 27 is formed. In each of the elements 26a and 27a, the elements 26a and 27a are arranged alternately and in parallel. A part of the blocking layer 31 is interposed between both elements, and the stripe electrode 26 and the sub-stripe electrode 27 are electrically insulated. The sub-stripe electrode 27 is
It is a conductive member for outputting an electric signal of a level corresponding to the amount of latent image charge accumulated in the electricity storage unit 29 formed at the substantially interface between the recording photoconductive layer 22 and the charge transport layer 23.

The sub-stripe electrode 27 is made of Al,
The element 2 is coated with a metal such as Cr and has a light-shielding property with respect to the reading light L2.
Even in the reading photoconductive layer 24 corresponding to 7a, some charge pairs may be generated by a slight reading light transmitted through the element 27a.

The blocking layer 31 is formed of the same material and the same method as those of the first embodiment, but the function thereof is the same as that of the first embodiment, and the sub-stripe electrode 27 is used. It also has a function of preventing the dark current noise generated at the edge of 1 from accumulating in the power storage unit 29 and becoming offset noise. Further, since the material forming the blocking layer 7 contains a dye that absorbs the reading light as in the first embodiment, the reading light scattered in the electrostatic recording body 20 is used for reading. In the electrostatic recording body 20, it is possible to reduce a decrease in sharpness in the longitudinal direction of the element 26a caused by reaching a region adjacent to the reading light incident surface of the photoconductive layer 24 in the longitudinal direction of the element 26a. The scattered reading light is adjacent to the element 26a on the reading light incident surface of the reading photoconductive layer 24 and is adjacent to the element 27a.
It is possible to reduce the deterioration of image quality caused by reaching the area corresponding to a.

Here, the amount of the dye contained in the material forming the blocking layer 31 is ηr, which is the discharge efficiency of the element 26a in the reading light irradiation region by the reading light, and one pixel next to the reading light irradiation region by the reading light. When the discharge efficiency of the element 26a in the region of is ηrn, the conditional expression ηr / Ηrn ≧ 2, the discharge efficiency of the element 26a in the reading light irradiation region by the reading light is ηr, and the discharge efficiency of the element 27a in the reading light irradiation region by the reading light is ηs. / Η
Adjust so as to satisfy s ≧ 2.

Further, the element 26 is provided between the electrostatic recording body 20 (reading light side conductive layer 25) and the reading light scanning means 93.
The irradiation intensity of the reading light L2 between the element 26a and the element 27a and at the portion corresponding to the element 27a is smaller than the irradiation intensity of the reading light L2 at the element 26a. As described above, a light-shielding film (not shown) made of a member having poor light transmittance is provided. As a result, the reading light L
2 is irradiated to only the element 26a.

Next, a basic method of recording image information on the electrostatic recording body 20a as an electrostatic latent image and reading the recorded electrostatic latent image will be briefly described. FIG. 5 is a schematic view of a recording / reading system using the electrostatic recording body 20a.

This recording / reading system comprises an electrostatic recording body 20.
a, recording light irradiation means 90 (not shown), current detection circuit 71 as image signal acquisition means, reading light scanning means 93.
(Not shown). The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted unless particularly necessary.

The current detection circuit 71 obtains an image signal of a level corresponding to the amount of latent image charge by reading out the charge corresponding to the latent image charge accumulated in the storage unit 29 through the sub-stripe electrode 27. , A plurality of current detection amplifiers (not shown) connected to each element 26a of the stripe electrode 26.

By applying a control voltage so that the stripe electrode 26 and the sub-stripe electrode 27 have the same potential, the electric field distribution formed between the recording light side conductive layer 21 and the reading light side conductive layer 25 is made uniform. You can In the present embodiment, the stripe electrode 26 and the sub-stripe electrode 27
Is at ground potential during both recording and reading.

Next, a method of recording image information on the electrostatic recording body 20a as an electrostatic latent image and reading the recorded electrostatic latent image in the recording / reading system having the above-described configuration will be described. First, regarding the electrostatic latent image recording process, FIG.
Description will be given with reference to the charge model shown in FIG. In addition,
The negative charge (−) and the positive charge (+) generated in the photoconductive layer 22 by the recording light L1 are represented by − or + surrounded by ◯ in the drawing.

When recording an electrostatic latent image on the electrostatic recording body 20a, a DC voltage is applied between the recording light side conductive layer 21 and the stripe electrode 26 and the sub-stripe electrode 27 to charge them. Next, the subject 9 is bombarded with radiation, and the electrostatic recording body 20a is irradiated with the recording light L1 that carries the radiation image information of the subject 9 that has passed through the transmission portion 9a of the subject 9.
Then, positive and negative charge pairs are generated in the recording photoconductive layer 22 of the electrostatic recording body 20a, and the negative charges in the pair move to the power storage unit 29 along the electric field distribution. At this time, the negative charges are accumulated in the positions corresponding to the elements 26a and 27a.

On the other hand, the positive charges generated in the recording photoconductive layer 22 move toward the recording light side conductive layer 21 at high speed, and from the power source 72 at the interface between the recording light side conductive layer 21 and the photoconductive layer 22. The injected negative charge recombines with the charge and disappears. Further, since the recording light L1 does not pass through the light shielding portion 9b of the subject 9, the portion below the light shielding portion 9b of the electrostatic recording body 20a does not change at all.

In this way, by irradiating the subject 9 with the recording light L1, charges corresponding to the subject image can be accumulated in the electricity storage unit 29 which is the interface between the photoconductive layer 22 and the charge transfer layer 23. become able to. Since the amount of the latent image charge (negative charge) accumulated is substantially proportional to the dose of the radiation that has passed through the subject 9 and has entered the electrostatic recording body 20a, this latent image charge carries the electrostatic latent image. The electrostatic latent image is recorded on the electrostatic recording body 20a.

Next, when the electrostatic latent image is read from the electrostatic recording body 20a, the recording light side conductive layer 21 is set to the ground potential,
By moving the reading light irradiation means in the longitudinal direction of the element 26a, that is, by sub-scanning, the entire surface of the electrostatic recording body 20a is scanned and exposed by the reading light L2 in a line shape. Due to the scanning exposure of the reading light L2, positive and negative charge pairs are generated in the photoconductive layer 24 to which the reading light L2 corresponding to the sub-scanning position is incident.

Then, the latent image charges of the portions corresponding to the two elements 27a, that is, the sky portions of both elements 27a are sequentially read out through the two elements 27a. That is, as shown in FIG. 5B, discharge occurs from the element 26a located at the center of the pixel toward the latent image charges (in the sky) corresponding to the elements 27a on both sides of the element 26a. proceed. In addition,
In order to extract more signal charge, the element 27
It is preferable that the width of a is wider than the width of the element 26a.

Further, the reading light L2 'which is scattered inside the element 26a and the blocking layer 31 and reaches the region adjacent to the reading light incident surface of the reading photoconductive layer 24 in the longitudinal direction of the element 26a is the elements 26a and 26a. Compared with the reading light L2 that passes through the blocking layer 31 and reaches the reading light incident surface of the reading photoconductive layer 24 at a substantially shortest distance,
Blocking layer 3 containing a dye that absorbs reading light L2
Since it travels a long distance inside 1, the amount of light absorbed is larger than that of the reading light L2 that arrives at a substantially shortest distance.
Therefore, it is possible to reduce a decrease in sharpness in the longitudinal direction of the element 26a due to light leakage to a region adjacent to the reading light incident surface of the reading photoconductive layer 24 in the longitudinal direction of the element 26a.

Also, as shown in FIG.
a and the blocking layer 31 are scattered inside the reading photoconductive layer 24 and reach the area corresponding to the element 27a adjacent to the element 26a on the reading light incident surface of the reading photoconductive layer 24.
And a long distance within the blocking layer 31 containing a dye that absorbs the reading light L2, as compared with the reading light L2 that reaches the reading light incident surface of the reading photoconductive layer 24 at a substantially shortest distance. Therefore, a larger amount of light is absorbed as compared with the reading light L2 that arrives at a substantially shortest distance. Therefore, it is possible to reduce the deterioration of the image quality of the read image due to light leakage to the area corresponding to the element 27a adjacent to the element 26a on the read light incident surface of the read photoconductive layer 24.

In this electrostatic recording body 20a, the electricity storage unit 29 is provided via the reading photoconductive layer 24 and the charge transport layer 30.
A capacitor C _{* c} is formed between and the sub-stripe electrode 27. Even if the sub-stripe electrode 27 is provided, the conductive layer 21 and the power storage unit 2 are interposed via the recording photoconductive layer 22.
Capacitor C _{* b} formed between the capacitance C _a of the capacitor C _{* a,} and the stripe electrode 26 through the reading photoconductive layer 24 and charge transport layer 23 and the storage unit 29 formed between the 9 There is substantially no significant effect on the capacitance C _b of the.

[0077] In this case, the capacitor _C * b, and consider the capacity of _{C * c,} the capacitance ratio _{C *} b: the _{C * c,} each element 26a, the width of the 27a ratio _W b: the _{W c.} As a result, at the time of reading, the amount of positive charge Q _{+ b} distributed to the capacitor C _{* b} can be made relatively smaller than in the case where the sub-stripe electrode 27 is not provided, and flows out from the electrostatic recording body 20a to the outside. The current can be made relatively higher than that in the case where the sub-stripe electrode 27 is not provided.

Although the preferred embodiments of the photodetector of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments.

For example, in the above description, the storage layer is formed at the interface between the recording photoconductive layer and the charge transport layer by charging the recording light side conductive layer with a negative charge and the reading light side conductive layer with a positive charge. Although the one in which the negative charge is accumulated in the part has been described, the present invention is not necessarily limited to such a thing, and each may be a charge of opposite polarity, and when reversing the polarity in this way, Only a slight modification such as changing the charge transport layer functioning as a hole transport layer to a charge transport layer functioning as an electron transport layer is required.

For example, as the recording photoconductive layer, the above-mentioned amorphous selenium a-Se, lead oxide (II), and lead iodide (I) are used.
Photoconductive materials such as I) can be used as well, and N-trinitrofluorenylidene aniline (TN) can be used as a charge transport layer.
FA) dielectrics, trinitrofluorenone (TNF) / polyester dispersions, asymmetric diphenoquinone derivatives are suitable, and the above-mentioned metal-free phthalocyanines and metal phthalocyanines can be similarly used as the reading photoconductive layer.

Further, in the above description, the electricity storage section is formed at the interface between the recording photoconductive layer and the charge transport layer, but the invention is not limited to this, and it is described in, for example, the above-mentioned US Pat. No. 4535468. As described above, the power storage unit may be formed by a trap layer that accumulates latent image charges as traps.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a recording / reading system using a photodetector according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a process of recording an electrostatic latent image on an electrostatic recording body according to the first embodiment of the present invention.

FIG. 3 is a diagram showing scattered light when reading the electrostatic recording body according to the first embodiment of the invention.

FIG. 4 is a perspective view of an electrostatic recording body according to a second embodiment of the present invention.

FIG. 5 is a charge model (A) showing an electrostatic latent image recording process and a charge model (B) showing an electrostatic latent image reading process when the electrostatic recording body according to the second embodiment of the present invention is used. )

FIG. 6 is a diagram showing scattered light when reading an electrostatic recording body according to a second embodiment of the present invention.

[Explanation of symbols]

10, 20 Electrostatic recording material 1, 21 Recording light side conductive layer (second conductive layer) 2.22 Photoconductive layer for recording 3, 30 Charge transport layer 4, 24 Photoconductive layer for reading 5, 25 Read light side conductive layer (first conductive layer) 6,26 stripe electrodes 6a, 26a elements (light irradiation linear electrodes) 7,31 Blocking layer 23, 29 power storage unit 27 sub electrode 27a element (charging linear electrode) 70 power supply 80, 71 Current detection circuit 81 Detection amplifier

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/32 H01L 31/10 A F term (reference) 4M118 AA05 AA10 AB01 CB05 CB14 CB20 DD01 DD09 GA10 5B047 AA17 AB02 BB04 BC01 CB05 5C024 AX12 AX17 CX37 EX01 GX07 5C051 AA01 BA02 DA06 DB01 DB04 DB06 DB18 DB28 DC02 DC07 5F049 MA20 MB05 MB08 NA04 NB03 NB05 SE03 SE04 SE05 SE09 SZ10 UA12 UA13 WA07

Claims (5)

[Claims] 1. A first conductive layer having transmissivity for recording light, a recording photoconductive layer exhibiting photoconductivity by being irradiated with the recording light, and a recording conductive layer according to a light amount of the recording light. A storage unit for accumulating a certain amount of electric charges as latent image charges, a reading photoconductive layer exhibiting photoconductivity upon receiving irradiation of reading light, and a large number of light irradiation lines having transparency to the reading light. A second conductive layer provided with a striped electrode, in a photodetector provided with an electrostatic recording body laminated in this order, between the reading photoconductive layer and the light irradiation linear electrode,
A photo-detecting device comprising an absorbing means for absorbing the reading light. 2. A first conductive layer having transmissivity for recording light, a recording photoconductive layer exhibiting photoconductivity by being irradiated with the recording light, and a light-transmitting layer according to the amount of the recording light. A storage unit for accumulating a certain amount of electric charges as latent image charges, a reading photoconductive layer exhibiting photoconductivity upon receiving irradiation of reading light, and a large number of light irradiation lines having transparency to the reading light. -Shaped electrode and a large number of charging linear electrodes, and a second conductive layer in which the light irradiation linear electrodes and the charging linear electrodes are alternately arranged are laminated in this order. A photodetector provided with an electrostatic recording body, comprising an absorbing means for absorbing the reading light between the reading photoconductive layer and the second conductive layer. 3. The absorbing means defines the discharge efficiency of the light irradiation linear electrode in the reading light irradiation region by the reading light as ηr, and the next one pixel of the reading light irradiation region by the scattered light of the reading light. Where ηrn is the discharge efficiency of the linear electrode for light irradiation in the region of / Ηrn ≧ 2
The photodetector according to claim 1 or 2, characterized in that: 4. The light absorbing linear electrode and the charging linear electrode, which are adjacent to each other, have a discharge efficiency ηr of the light irradiating linear electrode in a reading light irradiating region by the reading light. When the discharge efficiency of the charging linear electrode due to scattered light in the reading light irradiation area by the reading light is ηs, the conditional expression ηr The photodetector according to claim 2 or 3, characterized in that / ηs ≧ 2 is satisfied. 5. The reading light is transmitted between the reading photoconductive layer and the light irradiating linear electrode, and between the light irradiating linear electrode and the charging linear electrode. And a blocking layer having a blocking property against the charge injection from the light irradiation linear electrode and the charging linear electrode is provided, and the absorbing means is contained in the blocking layer. The photodetector according to claim 1, wherein the photodetector is a dye that absorbs the reading light.