JPH0360297A - Image pickup device and its operating method - Google Patents

Abstract

PURPOSE:To reproduce an incident optical image on a photoconductive face wholly with fidelity by varying an electron beam on-period and an electron beam off-period in one field in time series so as to set a scanning area concentrical to the photoconductive film. CONSTITUTION:The device consists of an object 1, a lens 2, a convergence deflection coil 3, an image pickup tube 4, a signal amplifier circuit 5, a convergence deflection circuit 6, a power supply circuit 7, an electron beam control circuit 8, a video monitor 9, a photoconductive film 10 and an electron beam 11. Then the deflection angle of the scanning electron beam 11 is increased more than that of a conventional device and the blanking period of the electron beam 11 is varied sequentially for each horizontal scanning period to expand the effective scanning area of the electron beam 11 to the entire area of the circular photoconductive film 11. Thus, the incident optical image formed to the entire area of the circular photoconductive film 10 is read as a video signal with fidelity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device, and more particularly to an imaging device that scans only a circular region on a photoconductive film surface of an imaging tube with an electron beam.

[Conventional technology]

Generally, an image pickup tube consists of a photoconductive target section that converts an incident light image or an X-ray image into charge and stores it, and an electron beam generation section that reads the accumulated charge.
Widely used in television broadcasting and industrial fields. In television broadcasting systems, the electron beam scanning method, such as the number of scanning lines of the image pickup tube and the scanning area, is standardized in each country, but in the industrial application field, for example, the scanning area, scanning time, etc. may be changed as necessary. and is used.

Regarding the electron beam convergence/deflection method of the image pickup tube, four types of methods are known, each combining a deviation method and an electric field method. Regarding these, for example, Imaging Engineering, Coronasha (1970), Image Electronic Enclosure.

It is stated in Coronasha (1972).

[Problem to be solved by the invention]

In the above-mentioned conventional technology, only a specific rectangular area of the optical image or X-ray image (hereinafter collectively referred to simply as the incident light image) formed over the entire circular photoconductive film of the image pickup tube is exposed to the electron beam. In order to scan and read, the incident light image outside the effective scanning area is discarded without being extracted as a video signal.

Furthermore, if the conventional scanning method is used and only the scanning area is expanded to extract signals from the entire photoconductive surface, the electron beam will have to be scanned to the target electrode exposed at the photoconductive periphery. , in this case, image distortion may be exceeded or 'I!' due to the influence of secondary electrons. ! There were problems such as deterioration of Ii quality.

An object of the present invention is to provide an imaging device that can faithfully read out an incident light image formed over the entire area of a circular photoconductive film as a video signal. The purpose is to increase the amount and resolution.

[Means to solve the problem]

The above purpose is to make the deflection angle of the scanning electron beam larger than before, and to change the blanking period of the electron beam by −qJ for each horizontal scanning period, thereby changing the effective scanning area of the electron beam to a circular photoconductive film surface. This will be achieved by expanding to the entire area.

[Effect]

FIG. 1 is a diagram showing an example of an imaging device according to the present invention.

l is the object, 2 is the lens, and 3 is the convergence/deflection coil.

4 is an image pickup tube, 5 is a signal amplification circuit, 6 is a convergence deflection circuit, and 7
Haden1lIKl! ! ! 8 is an electron beam control circuit, 9
10 is a photoconductive film, and 11 is an electron beam.

FIG. 1(b) shows how the photoconductive film of the image pickup tube is scanned by an electron beam in this apparatus.

The solid line 1jA12 in the figure is an electron beam scanning line, the dotted line 13 is an electron beam cutoff line, and the broken line 14 is a return line. Although the figure shows a case where the number of scanning lines is 9 for simplicity, the actual number is 525 in the current domestic broadcasting standard, and over 1000 in a commercial definition television system. In the present invention, the voltage of the convergence/deflection circuit 6 is set in advance so that the deflection angle of the electron beam corresponds to a region including the photoconductive film connected by points A, B, C, and D.

Next, in actual operation, the electron beam control circuit 8 turns the electron beam ON only during the time period corresponding to the solid line in FIG. Off.

FIG. 2 shows the current waveform (a) of the horizontal deflection coil in the image pickup apparatus of the present invention and the voltage waveform (a) between the first grid of the image pickup tube and the cathode supplied from the electron beam control circuit 8.
b) (hereinafter referred to as electron beam blanking signal waveform)
FIG. (c) and (d) in the figure are
These are a current waveform of a horizontal deflection coil and an electron beam blanking signal waveform in the prior art, respectively.

The current waveforms (a) and (c) of the horizontal deflection coil are periodic sawtooth waves consisting of a horizontal deflection period 22 and a retrace period 23 for scanning the photoconductive film surface with an electron beam. In the present invention, the current waveform (a) of the deflection coil is made larger than (c) in order to widen the scanning area by the electron beam.

The electron beam blanking signal waveform in FIG. 2(b) is 1
During the electron beam cutoff period 24, the first grid potential is increased in the negative direction with respect to the cathode to cut off the electron beam within two horizontal scanning periods, and the first grid potential is brought close to the cathode potential to allow the electron beam to pass through. The electron beam ON period 25 for reading the incident light image on the conductive +tri is observed. In the conventional method, as described above, since the electron beam scanning area is rectangular, the ratio of the electron beam cutoff period 24 and the electron beam on period 25 is always constant, as shown in FIG. 2(d). . In contrast, in the present invention, as shown in FIG. 2(b), the electron beam on period is sequentially changed for each horizontal scanning period.

Specifically, the 11th! In the horizontal scanning of 1, only the uppermost end of the photoconductive surface shown in FIG. 1(b) needs to be scanned, so that the electron beam on period 25 requires only a small amount of metal as compared to the horizontal scanning period 22.

Below, as the horizontal scanning progresses, the electron beam on period 25
is gradually lengthened, and becomes longest when the horizontal scanning line reaches the center of the photoconductive surface. As the horizontal scanning progresses further, it gradually becomes shorter, and when it reaches the top end of the photoconductive rfrj, l
Finish electron beam scanning of the field. In this way, by repeating the operation of scanning only the entire circular photoconductive film with an electron beam as shown in FIG. And it can be taken out continuously.

As described above, according to the present invention, by changing the electron beam on period 25 and the electron beam off period 24 in the F-field in time series, it is possible to set a scanning area concentric with the photoconductive film 0, thereby improving light guide. The incident light image can be reproduced completely and faithfully.

The present invention has been explained above using an image pickup tube using an electromagnetic focusing method or an electromagnetic polarization method. However, since the present invention is not related to the electron beam focusing method itself, the focusing and deflecting method described in the "Prior Art" section is It goes without saying that a variety of different image pickup tubes can be used.

FIG. 3 is a diagram showing an example of a reproduced image according to the present invention.

FIG. 3(a) is a diagram showing the appearance of an incident light image formed on the photoconductive surface of the image pickup tube, in which 3 is a substrate, 32 is a photoconductive film, and 3 is a photoconductive film.
3 is a formed optical image.

FIG. 3(b) shows a reproduced image using the imaging device according to the present invention, and FIG. 3(c) shows a reproduced image using the conventional technique. As is clear from FIGS. 3(b) and 3(Q), according to the present invention, the incident light image can be reproduced more widely and more faithfully. The above-mentioned effects are particularly noticeable in an image pickup tube that is used with a high target voltage, such as an avalanche multiplier type image pickup tube.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Embodiment 1 FIG. 4 is a block diagram of a blanking signal generating means of an embodiment using an image pickup tube that focuses and deflects an electron beam using a magnetic field.

Counter 41. ROM42. Latch 43. voltage converter 4
Consists of 4. Counter 41. When a clock signal is manually input to the latch 43, the counter 41 counts the input clock and specifies the address of the ROM 42 according to the count. The ROM 42 outputs data stored in advance at a designated address to the latch 43.

Here, the data stored in the ROM 42 in advance is determined by the clock signal cycle. In this embodiment, a case will be described below in which a 1.575 MHz clock signal is used. In this case, the clock period is 0.635μs
Therefore, ll! ! The built-in blanking signal (period: 63.5 μS) data per horizontal scan is 100
The time will be divided equally. In this way, 1
Electron beam blanking signal waveforms corresponding to two horizontal scanning periods and a retrace period can be obtained. If the same operation is performed for 525 horizontal scanning lines, the electron beam blanking signal waveform for field ■ will be obtained, and this
Signal waveforms for fields are stored in the ROM 42 in advance.

The latch 43 is a ROM that is output by a clock signal.
The built-in data of 42 is held until the next clock signal is input manually, and is output to the voltage converter 44. The voltage converter 44 boosts the TTL level electron beam blanking signal waveform of the launch 43 to a maximum of -200V and applies it between the first grid electrode and the cathode electrode of the image pickup tube.

As described above, it is possible to realize an electron beam blanging signal whose uf is changed in time series for one field.

From the second field onward, the same blanking signal as for the first field may be used, so the address of the ROM 42 is returned to the first address after the first field is completed. for that purpose,
A vertical synchronization signal is manually applied to the reset line of the ROM 42 to generate a signal at the end of each field.

By using the enclosure described above, it is possible to perform the electron beam scanning shown in FIG. As shown in (b) and (Q), the electron beam scanning area can be finely adjusted by varying the current waveforms of the horizontal and vertical deflection coils using the 11-variable resistor 45.

Through the above steps, the electron beam control circuit 8 shown in the drawing can be constructed.

Embodiment 2 FIG. 5 shows the X! This is an example of a diagnostic device. 5 is an X-ray source, 52 is a subject, 53 is a fluorescent surface,
54 is a photocathode, 55 is a fluorescent surface, 56 is a tandem lens, 57 is an imaging device, and 9 is a video monitor.

As shown in the figure, the XI& transmitted through the subject 52 is the circular xm hyperemia 53 of the X-ray image intensifier.
The photoelectrons are projected onto the photoelectrons and further converted into photoelectrons by the photoelectric blood 54.

The above photoelectrons are accelerated and focused by an electron lens, causing hyperemia 5
5 and is converted into a light image. The optical image of the fluorescence If 1155 is converged by the tandem lens 56 and reproduced on the video monitor 9 by the imaging device 57.

In other words, since the X-ray image of the subject 52 is output as a circularly framed optical image by the XvA image intensifier, an imaging device that scans a circular area with an electron beam is used as in this embodiment. As a result, the output image of the X-ray image intensifier can be observed completely, and X-ray diagnosis of a wider region of the subject can be performed with ease.

Embodiment 3 FIG. 6 is an example of an image detection device that combines the imaging device and microscope device described in Embodiment 1, where 6 is a sample, 62 is a microscope device, 57 is an imaging device of the present invention, and 9 is a video monitor. It is.

As shown in the figure, the image of the sample 61 is magnified by a microscope device and projected onto an imaging device 57. Since this projected image is generally a circularly framed image, by using it in combination with the imaging device 57 that scans a circular area with an electron beam, the effect is great as in the second embodiment.

〔Effect of the invention〕

As is clear from the above, according to the present invention, since the beam-on period during the blanking signal can be arbitrarily set, it is possible to scan the electron beam over the entire photoconductive surface of the image pickup tube, and it is possible to completely eliminate manual imaging. Can be output. In particular, if the device of the present invention is used in an X-ray diagnostic device or an image detection device, the amount of information can be greatly increased because all incident light images can be extracted as video signals, and the effect is great. be.

[Brief explanation of drawings]

FIG. 1(a) is a block diagram showing an example of the imaging device of the present invention, and FIG. 1(b) is a plan view showing electron beam scanning on the photoconductive film of the imaging tube in the device of the embodiment of the present invention. , Figure 2 (
a) and (b) are current waveforms and electron beam ranking signal waveforms of the horizontal deflection coil in the imaging device according to the embodiment of the present invention, respectively, and FIGS. 2(c) and 2(d) are diagrams of the horizontal deflection in the prior art, respectively. Current waveform of the coil and electron beam blanking signal waveform diagram, FIG. 3(a) is an incident light image on the image carrier tube, FIG. 3(b) is a reproduced image according to the embodiment of the present invention, and FIG. 3(c) is a conventional image. FIG. 4 is a block diagram of a blanking signal generating means according to an embodiment of the present invention. FIGS. 5 and 6 are block diagrams showing a schematic configuration of an apparatus according to another embodiment of the present invention. l...Subject, 2...Lens, 3...Convergence/deflection coil, 4...Image tube, 5...Signal amplification circuit, 6...
- Convergence/deflection circuit, 7... Power supply circuit, 8... Electron beam control circuit, 9... Image monitor IO... Photoconductive film, 11... Electron beam, 12... Electron beam scanning Line, 13...Electronic base cutoff line, Work 4...Return line, 2
Work...Horizontal deflection period, 22...Horizontal deflection period, 23
... Retrace period, 24... Electron beam cutoff period, 25... Electron beam on period, 31... Transparent substrate, 32... Photoconductive film, 33... Imaged light image,
41... Counter, 42... ROM, 43... Latch, 44... Voltage converter, 45... Variable resistor, 5
DESCRIPTION OF SYMBOLS 1... X-ray source, 52... Subject, 53... Fluorescent surface, 54... Photocathode, 55... Fluorescent space, 56...
- Tandem lens, 57... Imaging device, 61... Sample, 62... Microscope device. I + k)) Envy cause button (su) (C/) ¥341 power (ku) ('r)> (shi) fan first cause

Claims (1)

[Claims] 1. At least a circular substrate, a thin film electrode stretched on the substrate, a circular photoconductive film formed on the electrode, and electrons for sequentially scanning the surface of the photoconductive film. An imaging device comprising at least an image pickup tube equipped with a beam generating section, and a scanning electron beam control circuit such that a region on a photoconductive film surface scanned at a constant speed by the electron beam becomes circular. . 2. An imaging apparatus characterized in that the scanning electron beam control circuit according to claim 1 has a function of sequentially varying the electron beam blanking period for each horizontal scanning period. 3. An X-ray diagnostic apparatus comprising at least the imaging device according to claim 1 and an X-ray image intensifier. 4. An image detection device comprising at least an imaging device according to claim 1 and a microscope device. 5. At least a circular substrate, a thin film electrode extended on the substrate, a circular photoconductive film formed on the electrode, and an electron beam generator for sequentially scanning the surface of the photoconductive film. 1. A method of operating an imaging device, comprising scanning only a circular region on a photoconductive film surface with an electron beam at a constant speed in an imaging tube.