JPH02289865A - Electrostatic camera using a photomultiplier tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-resolution and high-sensitivity electrostatic camera.

[Conventional technology]

Conventionally, silver halide photography, electrophotography, television photography, and photography using solid-state image sensors (CCD, etc.) have been used as high-resolution photography techniques, but with these methods, the green color of the image is of high quality. , if the resolution is high, the processing process! If the process was simple, there would be a lack of memory function or a basic deterioration of image quality.

The applicant aims to provide these products with high quality, high resolution, simple processing steps, long-term storage, and the ability to store stored characters, line drawings, images, and code (1,0) information according to the purpose. We have already proposed an electrostatic camera that can record and reproduce images repeatedly at desired image quality (Japanese Patent Application No. 121591/1983).
).

[Problem to be solved by the invention]

Incidentally, such an electrostatic camera has the feature of being capable of extremely high-resolution analog photography, but in order to obtain a bright image, it is necessary to make the voltage applied between the photoreceptor and the charge holding medium sufficiently large.

However, if the voltage is increased too much, discharge breakdown will occur, so there is a limit to how high the voltage can be to obtain a sufficiently bright image. Particularly when the amount of incident light is small, it is difficult to obtain a satisfactory image.

The present invention is intended to solve the above-mentioned problems, and aims to provide an electrostatic camera using a photomultiplier tube that has high resolution and can be made highly sensitive.

[Means for Solving the Problems] To this end, an electrostatic camera using the photomultiplier tube of the present invention has a photocathode that converts an incident optical image into an electronic image, and an image of the photocathode that is incident through an electron lens. A multi-channel plate that forms an image on the surface, a phosphor screen that emits fluorescence when the electron image multiplied by the multi-channel plate is incident, and a transparent electrode laminated on the photoconductive layer, and an optical image from the phosphor screen is formed. A photoconductor whose light is incident on a photoconductive layer through a transparent electrode, and a charge retention medium disposed opposite to the photoconductor and having an electrode and an insulating layer laminated on a substrate, the transparent electrode of the photoconductor and the charge retention medium A voltage is applied between the electrodes of the phosphor screen, and an incident optical image from the phosphor screen is recorded as an electrostatic latent image on the charge retention medium.

[Effect]

The present invention combines a photomultiplier tube such as an image intensifier or an image converter with an electrostatic camera, sufficiently amplifies the amount of incident light with the photomultiplier tube, and then exposes the image through a photoreceptor to a charge-retaining medium. By forming an electrostatic latent image on the image, it becomes possible to realize a highly accurate and highly sensitive electrostatic camera.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an electrostatic camera using the photomultiplier tube of the present invention. In the figure, l00 is an image/reflection tensifier, 101 is a subject, l03 is an objective lens, 1
05 is a photocathode, 107 is an electron lens, 109 is a multi-channel plate (MCP), ll is a fluorescent surface, 12
0 is a photoreceptor, I20a is a transparent substrate, 120b is a transparent electrode, 120c is a photoconductor, 122 is a switch, 124 is a charge retention medium, 124a is an insulating layer, 124b is an electrode, 12
4c is a substrate.

The image intensifier 100 includes a photoelectric surface 105 that converts light into electrons, an electron lens 107 that focuses electrons emitted from the photocathode onto a predetermined position, an MCP 109 that amplifies incident electrons several thousand times, and an MCP. A phosphor screen 111 that converts an incident electron image into a light image is incorporated into a vacuum tube. On the back side of this fluorescent screen, a transparent substrate 1 has a transparent electrode 120b and a photoconductor 120c laminated thereon.
20a is connected. Furthermore, 10μ is applied to the photoreceptor 120.
The electrode 124b is placed on the substrate 124C through a gap of about m.
A charge holding medium 124 having an insulating layer 124a laminated thereon is disposed facing each other, and a battery E is connected via a switch 122 between the transparent electrode 120b and the electrode 124b.

In such a configuration, when an image of the subject 101 is formed on the photocathode 105 via the objective lens 103, electrons are emitted from the photocathode in response to this human optical image. The emitted electrons are concentrated by the electron lens l07 and sent to the MCP.
An electron image is formed on the incident surface side of 109. MCP109 is a thin glass plate with a diameter of 25a+m and a thickness of about 0.48ta, and has countless 12μmφ thin holes, or channels.When electrons enter these channels, the potential gradient inside the MCP changes. The electrons are attracted and collide with the inner wall dozens of times before exiting from the other side.

During this collision, the channel wall emits secondary electrons,
The output electrons are multiplied several thousand times or more compared to the incident electrons.

The MCP consists of a total of 1.5 million channels, each of which corresponds to a pixel, and each pixel is multiplied at the same time.

The multiplied output electrons are attracted by the electric field and collide with the phosphor screen,
emits fluorescence. This fluorescence is several thousand times brighter than the amount of incident light, and enters the photoconductor 120e via the transparent substrate 120a and transparent electrode 120b.

As a result, carriers are generated within the photoconductor 12Oc, and the exposed portion becomes conductive. As a result, a strong electric field is applied in the gap between the conductive portion and the charge retention medium, causing corona discharge, and charges corresponding to the incident optical image are accumulated on the insulating layer 124a.

In this way, the charges accumulated on the insulating layer are stably held, making it possible to hold the electrostatic latent image in a stable state for a long period of time. This electrostatic latent image can be read at any time by toner development, potential reading, or optical reading using electro-optic effects.

Note that the switch 120 can be provided with a shutter function since an image will not be formed on the charge holding medium unless it is turned ON.

In the above example, a transparent electrode and a photoconductor were laminated on the phosphor screen via a transparent substrate, but if the transparent substrate was thick, it would be a hindrance to increasing the resolution of the image, so this was omitted and the transparent electrode and photoconductor were laminated via a transparent substrate. An electrode may be formed on the phosphor screen and a photoconductor may be laminated thereon.

Furthermore, instead of a voltage shutter using a switch, a mechanical shutter may be provided in front of the photocathode, or the distance between the photoreceptor and the charge holding medium may be made variable, and the distance between the photoreceptor and the charge holding medium may be made variable, and the distance between the photoreceptor and the charge holding medium may be varied, and the distance between the photoreceptor and the charge holding medium may be varied, and the distance between the photoreceptor and the charge holding medium may be varied. A shutter function may be provided by changing the distance from the charge holding medium. Further, in the above embodiment, an example using an image intensifier was explained, but the wavelength range of the incident light is infrared or ultraviolet, and an image converter that takes such an invisible image and converts it into a visible image is used. It goes without saying that it may be used in combination with.

〔Effect of the invention〕

As described above, according to the present invention, extremely high resolution can be achieved by arranging a photomultiplier tube with an amplification function of several thousand times in front of the photoreceptor and performing image exposure through the photomultiplier tube. At the same time, it becomes possible to realize a highly sensitive electrostatic camera.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an electrostatic camera using the photomultiplier tube of the present invention. lOO...Image intensifier, l05...
・Photocathode, 107...Electronic lens, 109...Multi-channel plate, 111...Phosphor screen, 120...
...Photoreceptor, 120a...Transparent substrate, 120b...
Transparent electrode, 120c... Photoconductor, 122... Switch, 124... Charge retention medium, 124a... Insulating layer, 124b... Electrode, 124c... Substrate. i1 Nagi

Claims (4)

[Claims] (1) A photocathode that converts an incident optical image into an electron image, a multichannel plate where the image of the photocathode is formed on the entrance surface via an electron lens, and an electron image multiplied by the multichannel plate is incident. a phosphor screen that emits fluorescence, a transparent electrode laminated on the photoconductive layer, a photoreceptor whose optical image from the phosphor screen is incident on the photoconductive layer through the transparent electrode, and a photoreceptor placed opposite the photoreceptor, A charge holding medium is provided with electrodes and an insulating layer laminated on a substrate, and a voltage is applied between the transparent electrode of the photoreceptor and the electrode of the charge holding medium to statically transfer an incident optical image from the phosphor screen onto the charge holding medium. An electrostatic camera using a photomultiplier tube that records as an electrostatic latent image. (2) The electrostatic camera according to claim 1, wherein the transparent electrode is formed on a transparent support layered on the phosphor screen. (3) The electrostatic camera according to claim 1, wherein voltage is applied between the photoreceptor and the charge holding medium through a switch, and the switch performs a shutter action. (4) The electrostatic camera according to claim 1, wherein the incident optical image consists of light of a wavelength in a visible region or a non-visible region.