JPS5939159A - Electrostatic latent image readout device - Google Patents

Abstract

PURPOSE:To attain the observation of a dynamic picture, by dividing a picture into a dynamic picture and a still picture and improving timewise resolution during the observance of the dynamic picture even if the picture quality is reduced more or less. CONSTITUTION:Terminals 0-15 of an analog multiplexer 702 correspond to 16 paper-tablet electrodes of a current amplifier array 701. The 16-paper-tablet shaped electrodes are selected in corresponding to binary inputs A-D of an analog multiplexers 702 for attaining parallel series conversion. At the observance of the dynamic picture, a switch 704 is switched so as to be selected interlacingly, allowing to obtain a good reproducing picture even with a weak image exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for reading out an electrostatic latent image formed on a detector, and in particular includes an apparatus capable of reading out one screen at a desired speed with five images.

A method of forming an electrostatic latent image by imagewise exposure on a multilayered detector including a light-guiding vaI layer, and reading out the electrostatic latent image as a time-series electrical signal by scanning the detector with light is disclosed in Japanese Patent Laid-Open No. 54-3121.
It is already known for No. 9 and others.

Here, one of the well-known methods will be explained, and then its problems will be pointed out and an attempt will be made to solve them.

FIG. 1 is a block diagram of the electrostatic latent (image successive method), in which 101 is a transparent electrode, 102 is a photoconductor layer, 103 is an insulator layer, 1
04 is the interface between 102 and 103, 105 is the electrode, 106
and 107 are switches, 108 is a DC power supply, 109 is an output terminal, 110 is an output resistor, 111 is a full-surface irradiation light, 112
．． 113 and 114 are electric charges. 115 is negative film and is 11
5-(1) is a transparent part, 115-(21 is an opaque part. 11
6 is transmitted light, 117 is a beam light such as a laser, 11B is a rotating mirror or a vibrating mirror, lt 7-(4), 117
−<2) is the reflected light by the vibrating mirror 11B of 117, ll0
I is the current, and VIOI is the output voltage. Figure 1 (A)
Then, turn on 106, turn off 107, and set tOS to 10.
1 and 105 as shown to charge layers 102 and 103. When the entire surface is irradiated with light 111 in this state, the resistance of 102 decreases, causing charge injection,
The charge of lot reaches 104 as shown and the charge is 11
2,113 are accumulated. This is called a one-band turtle.

Next, when the light 111 is removed, that is, the light is set to a dark state, 106 is turned off, and 107 is turned on, 114 appears on 101, as shown in FIG.

In this state, when the entire surface is irradiated with light ill through the negative film 115 as shown in FIG.
The resistance of the portion irradiated by 116 decreases, and the charges on 112 on the interface 104, 114 on the electrodes 101 and 113 on the electrodes 105 disappear. Therefore, charges remain only in the portion corresponding to the portion 115-(21. This is called image exposure, and the remaining charge pattern is called an electrostatic latent image.

After this, as shown in FIG. 1, with the switch 106 turned off and 107 turned on, apply 117 to 118,
The reflected light 117-[11, l l 7-(2) is 10
When 1 is irradiated, the resistance of 102 in the irradiated portion decreases, the charge 112 of the insulating layer 103 is released via the output resistor 11O, 11O1 flows, and VIOI is generated at 109. Figure 1 (g) shows that the 1170 reflected light is 117-(11
This shows the state scanned from to 117-(2). In this way, the electrostatic latent image is generated by the current 1101t or the voltage VI
It can be read as OI.

As is clear from the figure, 'current 1101 ij 11
It does not flow in the part irradiated by 6, but flows only in the part not irradiated by l16. In other words, no current flows in the bright parts of the image,
Electric current power in the dark part of the image; skillful.

In the above explanation, it is assumed that the charge completely disappears in the bright area and the charge is completely retained in the dark area, but in this method, if there are 75 degrees in the bright and dark areas, it is assumed that the charge is completely destroyed in the bright area. A similar electrostatic latent image force is formed, and a current or voltage force corresponding to the electrostatic latent image is generated.

121J is an example of output using the method shown in Figure 41, where the horizontal axis is time;
In other words, the scanning method of the beam light 117 is one phrase, and the vertical axis is the current 110.
1 or 'voltage VIOI.

201 is the waveform of the bright area, and 202 is the waveform of the dark f? Waveform of B, 20
3 shows an example of a halftone waveform.

Note that the above explanation shows only the case where the optical scanning is performed in one dimension, but if the optical scanning is performed in two dimensions, the Qi signal can be obtained from the two-dimensional image of the first temple system 11 in the same way as the video signal. It will be done.

FIG. 3 shows how the conventional example described above is subjected to two-dimensional optical scanning to read out an electrostatic latent image. 301 it: Transparency in Figure 1'
Looking at polarization 101 from below, there are 41 hits.

302 to 306 are trajectories of optical scanning. The main scan of the light beam and the array scan in the direction of the arrow, that is, from the left to the right in the figure. The sub-scanning is performed by scanning in the order of 302.303°, 304.305 below T and G in the figure, and, although not shown, performs a number of main scans [7], and finally ends by scanning 306. Following this passage of time,
307.308°309.310,311,312,3
It is clear that the order of 13°314 ends with 315,316.

Note that various other latent image formation and readout processes are known.

By the way, since the charge accumulated as an electrostatic latent image undergoes self-discharge in a dark state called 1 dark decay, 307
A phenomenon occurs in which the signal obtained by optically scanning the position 316 is different from the signal obtained by optically scanning the position 316.

Still, this detector forms a capacitor with double-sided electrodes, and the capacitance C becomes ε5 C=-, and 6 is the 'ratio of materials between the electrodes M+'? Electricity rate, SL1
The area of the electrode and d are the distance between the electrodes. Therefore, the latent image of Marubenkumo Harukajiden? The time constant τ of the electrical system when performing optical scanning and reading out as an electrical signal is τ=Z i C where Zi is the input impedance of the electrical system, and τ is proportional to S. That is, if the area of the electrode is large, the time constant of the electrical system becomes large, and the speed of the electrical system becomes slow, and the striking and reading speed must be slowed down.

On the other hand, a detector as shown in FIG. 4 is well known.

That is, for example, the electrode 10 of the stacked detector shown in FIG.
1 to the striped electrode I and 1 elongated purple light 11 set
By using strip-shaped electrodes 501 in which a, 501b, 501C, etc. are lined up at minute intervals, and providing the same number of electrical systems as the electrodes, the electrode area in one electrical system can be reduced, and the drawbacks described above can be improved. Siteil. Further, the photoconductor layer 502I"i8e or -17d Cd8, 503 an insulating layer, 505.); is illuminated across the plane. 514 is a laser light source, 515 is a beam expander, 516
518 is a beam diverging lens;
The emitted beam becomes a sheet, and sub-scanning in the direction of the arrow is performed by the operation of the deflector.

FIG. 5 is a block diagram showing an example of an electrical processing circuit.
rnal of App7? ied Pbologra
pbicEngineeringVOR,4,/16
4. Fall! 1978. It is coupled to each current amplifier of the 178 current amplifier array, and the output signal of each current amplifier is converted into a time-series electric signal by being sequentially parallel-series converted from the end of the strip-shaped electrode by an analog multiplexer 606. That is, in 606, main scanning is performed with equal constraints. The output signal of 606 is sampled and held in 607, analog-to-digital converted in 608, and outputted to 610.
stored in digital memory. The signal stored in 610 is digital-to-analog converted in 611 to become a luminance signal of the main oscilloscope 612. 606,60
7°608 is the clock 16 generated by the oscillator 609
This clock signal is controlled by the 6130
612 with counter and 614 digital to analog converters
This is the main scanning signal. ! ! In addition, the same clock signal is 6
The signal is divided by 15 by the number of strip electrodes and converted into a sub-scanning signal 612 by a counter 616 and a digital-to-analog converter 617, and the electrostatic latent image 601 can be reproduced on 612.

In this example, the time it takes to obtain one pixel is 605°606
．． 607, 608, etc., and due to S/N constraints, the sampling time for one pixel is approximately 0.5 μ (8
). In addition, as an example, the size of the detector is 40
0x400■, the interval between the strip electrodes is 0.1 mm, and sampling is performed at intervals of 0 and 1 wn in the sub-scanning direction, the total scanning time Ill is = 8 crowns, which is very difficult to read out the electrostatic latent image. It takes a long time for
If the target image has movement, the conventional method cannot handle the problem.The present invention provides a method and apparatus that can handle such a moving target image. The present invention considers the cases of moving images and still images separately, and in the case of moving images, the temporal resolution is increased even if the image quality is slightly reduced, and in the case of still images, the image quality is improved even if the temporal resolution is lowered. It's better than the idea of hatakemeru.

In addition, while observing the movement of the target image, the idea is to obtain a high-quality still image at the moment that is considered optimal, so when observing a video, it is necessary to reduce the image quality slightly, narrow the field of view, or The purpose is to increase temporal resolution by reducing the image quality. Furthermore, in the case of moving images, compared to still images, even if the image quality is slightly degraded, the effect on human vision is lessened.

The example described above as the prior art uses the exposure process of a copying machine that uses a negative film as an original plate to provide a latent image, but a device that projects the original plate with a projection lens,
Furthermore, it can also be applied to the exposure process of a device that records projection or transmission images of three-dimensional objects. The exposure energy may be any energy that can form a latent image, such as visible light, non-5f light such as infrared light, or radiation such as X-rays. In particular, it is well known from xeroradiography that the light guide 11 is sensitive to X-rays, and the use of electrophotographic means in X-ray examination equipment, especially medical It is highly desired because it eliminates the need to use salt film, reduces X-ray staining due to improved sensitivity, and allows the readout signal to be immediately observed as a video image or subjected to various electrical operations. . Furthermore, even if the sensitivity of the photoconductor to X-rays is extremely low, a latent image can still be formed by intervening an image converter such as a fluorescent screen.

FIG. 6 shows an example of a 4-bit analog multiplexer in one embodiment of the present invention. 701 is a current amplifier array similar to 605, which connects each of the strip-shaped electrodes of the detector similar to 601 to an electrode, and amplifies the signal obtained from each electrode. In this example, it is assumed that there are 16 strip-shaped electrodes i, and 701 contains 16 current amplifiers. Each electrode of the strip-shaped electrode corresponds to 0 to 15 of 701 from the end. 702 is an analog multiplexer that performs parallel series conversion. 702's 0-15 is 701's 0-15
It corresponds to 702 binary numbers A, B, C,
J) Compatible with 1. Select 0 to 15 and perform parallel series conversion.

A 4-bit counter 703 counts clock pulses and outputs binary numbers Qinput IQB, QC.QD corresponding to the number of clock pulses.

704 A switch that turns off the output of the if counter 703 and the input of the analog multiplexer 702. In the case of still image observation, switch 704-1.704 is used as shown in the figure. -2
．． -3. -4 are switch contacts 704-6, respectively. -7.
-8. -9 is connected.

Table 1 Table 1 is a table showing the output of the counter 703 in FIG. 6, the input of the analog multiplexer 702, and the selected 'electrodes in correspondence.
1 shows the case of still image observation. It is clear from this table that, in this case, electrodes corresponding to the number of clock pulses are sequentially selected by the counter 703.

When observing a moving image 712, the switch 704-1. -2゜-3
, -, 4 are switch contacts 704-5°-6,-7, respectively.
, -8, and the output of the counter 703 and the input of the multiplexer 702 c;t as shown in column 712.

That is, the output of the counter 703 is shifted one bit higher than the input of the multiplexer 702, and the output of the counter 703 is shifted upward by one bit relative to the input of the multiplexer 702. 7
Since the least significant bit A of the input of o2 is grounded and always becomes "(]", the electrode selected by the multiplexer 702 is 1.
It's going to be a jump. Therefore, the time required for conversion by the multiplexer 702 once in the main scanning direction is % when observing a moving image compared to when observing a still image.

In this embodiment, a case has been described in which there are 16 strip-shaped electrodes, but even if the number of electrodes is increased, a structure with even more electrodes can be easily realized by increasing the number of counter pits. Also, using switch 7o4kl and digital multiplexer,
This can be achieved without contact. Furthermore, instead of using the counter 703, if a microcomputer or the like is used, any number of steps can be performed by programming.

On the other hand, if the main scanning direction is sampled one at a time in Fig. 7, the total number of pixels in the main scanning direction becomes a station, so it is recommended to increase the speed in the sub-scanning direction and make the number of sub-scanning lines H. Be realistic. In this case, since the main scanning time is %, the sub-scanning time is set to A.

FIG. 7(2) is a block diagram showing a signal for driving a deflector such as a galvanometer that performs sub-scanning as previously indicated at 604. At 801, a sub-scanning synchronization signal for observing a moving image is input, and this signal has a frequency four times that of observing a still image, and is shown at a wavelength 804.802 is a still image/moving image changeover switch. During static observation, 802-3 is connected to contact 1, and the sub-scanning synchronization signal of frequency A is input to the sawtooth wave generation circuit 803 compared to when observing moving images. Still 804,8057-t.

A resistor for setting the amplification factor of the sawtooth wave generation circuit 803, in this case, the switch 802-41. Resistor 804 is connected to i-contact-5 and selected, and sawtooth wave generating circuit 803 outputs waveform 805. When observing a video, switch 802-3
is connected to contact 2, contact 4 is connected to contact 6, and the amplification factor of the sawtooth wave generating circuit 803 is increased to 4 to output a waveform 806 to drive the deflector.

Therefore, if the procedure shown in FIG. 7.8 is executed, the total scanning time will be % when observing a moving image compared to when observing a still image, and in the above example, the total scanning time will be T.

Further, in the example shown in FIG. 6, the electrodes are sampled from the end, but if the counter 703 is replaced by a preset counter or a microcomputer is used, only a desired range can be sampled. If half of the strip electrodes are selected one at a time, the number of pixels in the main scanning direction becomes %.If 801 in Fig. 8 is a 1716 frequency dividing circuit, the amplification factor of 803 when waveform 805 is selected is 8 times. If the amplitude is %, then the total scanning time is 711. is 1/16, which is the repetition frequency E'21:L at which an image can be obtained, which is fast enough to handle slow moving images. In order to narrow the angle of view and increase the repetition frequency of image observation in this way, moving image observation is very effective when used as a means of measuring the timing of obtaining still images.

Also, for example, if the electrode selection is a strip-shaped electrode, skipping four halves of the electrodes, that is, selecting one out of every five electrodes, increasing the sub-scanning speed by 25 times, and sub-scanning half of the electrodes in the sub-scanning direction, the total scanning time will be T
, becomes, and the repetition frequency F3 at which the image is obtained becomes,
Fast enough to observe normal movement. Therefore, in this calculation example, the spatial resolution is 2 pea, - and the angle of view is 200.
Images between X200 are obtained with a temporal resolution of 12.5 frames per second.

In addition, 1. If the sub-scanning speed is further increased and an interlaced system similar to that used in television 7 is adopted, the temporal resolution in observation will be further improved. For example, if 2:l interlacing is used, a moving image of 25 frames per second can be obtained in a pseudo manner.

FIG. 8 shows another embodiment of the present invention, in which a plurality of magnetic poles of a strip-shaped electrode are short-circuited. 901 is a detector similar to that configured by 501 to 505, 902 is a strip-shaped electrode similar to 501, and 903° and 904 are stationary lI! ii@Picture changeover switch 905 is a current amplifier array similar to 605. Figure 8 (2) shows an example of short-circuiting two electrodes at a time;
9 is an example in which three wires are short-circuited, and when observing a video, 1.;[Switch 903 is l-3, 4-6, 7-9, 10-12°; 12°13
-15 is connected, and a jump selection as explained in FIG. 6 is made. As you can see from this example, any number of electrodes can be short-circuited. In this case, the signal currents obtained from the short-circuited electrodes are added, and the S/N improves by the number of short-circuited electrodes. Therefore, a good reproduced image can be obtained even if the image exposure is weak. In particular, when the present invention is applied to X-ray electrophotography, the amount of X-ray exposure can be reduced, which is very effective.

FIG. 9 shows another embodiment of the present invention, in which the output of the first-stream amplifier array is inputted to the analog multiplexer 1007 after passing through a summing circuit consisting of 1003 to 1006, and
It performs main scanning in the same way as the example in the figure. 1001 is 7
1002 is an analog multiplexer similar to 702, and 1OO8 is a switch. Addition circuits 1003 to 1006 are prepared in a number equal to % of the number of electrodes, and input to an analog multiplexer 1007. During moving images, the analog multiplexer 1007 is selected by a switch 1008, and addition is performed for two electrodes at a time. This adder circuit is also capable of adding 411 lines. 'Also, by using an attenuator, it is possible to easily take the average, and it is also possible to select a combination of addition and interlacing.

Further, in the embodiments so far, the case of two-stage switching between still image observation and moving image observation has been described, but as is clear from the above description, switching can be performed in any number of stages.

In addition, in the above example, when selectively processing the electrical signals obtained from each elementary electrode, two or more of each elementary electrode of the strip-shaped electrode are short-circuited,
In addition, the configuration may be such that one or more can be skipped and selected.

In addition, the electric signal obtained from each elementary electrode of the strip-shaped electrode is
It may be configured such that more than one system is added or averaged, and one or more systems are skipped and selected.

Alternatively, the object may be irradiated with X-rays.
In that case, the moving image may be an X-ray fluoroscopic image, and the still image may be an X-ray image. In addition, the amount of X-ray exposure may be switched between X-ray fluoroscopy and X-ray photography, and furthermore, the X-ray generation during X-ray fluoroscopy and X-ray photography is controlled by the electrostatic latent image of the detector. It is also good to synchronize the formation and phototactic readout cycles.

As explained above, according to the present invention, it is possible to eliminate the inadequacy of moving image detection due to the long period in electrophotography using the YS scanning scanning method, to make it possible to observe moving images, and to enable high-speed scanning at a desired moment. It is possible to obtain high-quality still images.

In addition, by adding or averaging the signals, 8/N is improved when observing moving images. This has the effect of reducing the amount of fluoroscopic radiation during fluoroscopy.

[Brief explanation of the drawing]

In Fig. 1) (l 屓QO) is the well-known electrostatic latent image formation 274+
+, Diagram for explaining the dispensing process. Figure 2 V1,
111 waveform diagram. FIG. 3 is a diagram showing the two-dimensional trajectory of the detector. FIG. 4 is a perspective view of another detector and scanning device. FIG. 5 is a well-known air processing block diagram. FIG. 6 (5) is a diagram showing the main part showing an embodiment of the present invention. FIG. 7 (5) is a diagram showing a circuit for switching the sub-scanning speed; Figures (5) and (1,9
FIG. 3 is a plan view of main parts according to another embodiment. FIG. 9 is an electric circuit diagram showing still another embodiment. In the figure, 501 is a strip-shaped electrode, 501a, 501b, etc. are element electrodes of the strip-shaped electrode, 502 is a photoconductor layer, and 503Fi
Insulator layer, 505 is a plane electrode, 701 is a 1U current amplifier array, 702H7 analog multiplexer, 703 is a counter, 704 is a switch, 803 is a sawtooth wave generation circuit,
903 and 904 are still image/video changeover switches, 905 is a current amplifier array, 1003 to 1006 are adder circuits,
This is a 102H analog multiplexer. Applicant: Canon Co., Ltd., 3-30-2, Shimomaruko, Ota-ku, Tokyo, Figure 5, within Yanon Co., Ltd.

Claims (1)

[Claims] 1. An electrostatic latent image is formed on a multilayer detector including a photoconductive layer by exposing it from an irradiation source, and the detector is scanned with light to form an electrostatic latent image. In a device for reading out a drowsiness signal as a drowsiness signal, an electrode forming one layer of the multilayer structure of the detector is a strip-shaped electrode, and means for selectively processing electrical signals obtained from each electrode of the strip-shaped electrode by the optical scanning. An electrostatic latent image reading device comprising: 2. A case in which the drowsiness signal obtained from each electrode of the strip-shaped electrode is processed without selection, and an apparatus in which the drowsiness signal is selectively processed. 3. The electrostatic latent image reading device according to item 2, in which the processing is performed without the selection, and the selection processing. 4. A latent image reading device performs the selection process on each electrode of the strip-shaped electrode. 5. An apparatus in which the selection process is performed on two electrodes of each strip-shaped electrode. 6. The selection process is performed by adding or placing two or more systems of electricity obtained from each electrode of the strip-shaped electrode (No. 8). 7. The selection process is carried out using a limited range device for the strip-shaped electrode. When performing the selection process, the cycle of image exposure and optical scanning is repeated at regular intervals to obtain a moving image, and the electrostatic latent image reading device of the selection is used.