JPS63268377A - Image pickup device - Google Patents

Abstract

PURPOSE:To simplify circuit constitution, by using an image pickup element in which picture elements are arranged in a matrix shape, performing an operation to read out the signal load of all of the picture elements of one row for two or more times in one horizontal scanning period in order, and sending a read signal as a color difference signal or a luminance signal. CONSTITUTION:A bit output is shifted at every horizontal synchronizing signal fH inputted to a terminal 301, and also, each bit output outputs four readout pulses (a-d) in one horizontal scanning period, and the outputs of each bit are impressed on the base of each picture element of the image pickup element via horizontal lines H1-H4 at every row. The signal charge of the picture element of one row is read out for three times in one horizontal scanning period, and a readout signal of first time is allocated to the first color difference signal CW101 of a TCI signal, and the readout signal of second time to the second color difference signal CN102 of the TCI signal, and the readout signal of third time to the luminance signal 103 of the TCI signal. In such a way, it is possible to make an A/D converter, a D/A converter, and a memory device unnecessary.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an imaging device commonly used in television cameras, etc.
In particular, TCI (Time Compressed Int.
The present invention relates to an imaging device that generates an (egration) signal.

[Prior Art] Time Compressed Intgr (TCI), which compresses a luminance signal and a color difference signal in a time domain and multiplexes them in a time-division manner.
There is a television signal transmission system called the television signal transmission system.

There are various types of TCI, and FIG. 4 shows their basic waveforms. In this example, the luminance signal is compressed in the time axis to 172, and the color difference signal is compressed to 174 in the time axis and time-division multiplexed. FIG. 4 shows waveforms within one horizontal scanning period, where 101 is the first color difference signal Cw, 102
is the second color difference signal CN, 103 is the luminance signal Y, and 1
04 respectively represent horizontal synchronization signals.

As another example, a signal consisting of a combination of the first color difference signal CW and the luminance signal Y or a combination of the second color difference signal CN and the luminance signal Y is multiplexed within one horizontal scanning period, and every horizontal scanning period. There is also a method (color difference line sequential method) that uses other combinations of signals.

In a television camera that produces such a signal, for example, a signal IA configuration shown in FIG. 5 is used.

Figure 5 shows the luminance signal Y1 from the signal readout from the image sensor.
Although the part for producing the color difference signals C and CN is omitted, it is as follows. That is, the operation of reading the photoelectrically converted signal from the image sensor is performed once within one horizontal scanning period, and the signal read from the image sensor is colored R (red).
, G (green), and B (blue) signals, a matrix circuit generates a luminance signal Y1 and a color difference signal Cw and C,4.

Luminance signal Y1 color difference signal CW created in this way
The CN signal is then converted into a Tel signal using the configuration shown in FIG. In the figure, 201 is an A/D converter for converting the (analog) luminance signal Y into analog/digital (A/D).
A functional block including a D converter and a low-pass filter for removing aliasing noise during A/D conversion by the converter is shown, and similarly, 202 and 203 are for (analog) color difference signals Cw and CN, respectively. A/D of
1 shows a functional block including a transducer and a low-pass filter.

211.212 and 213 are each block 201.20
2. 203, a storage device for storing the A/D-converted luminance signal Y99 color difference signal Cw and C, respectively; 220 is a switch that switches and outputs one of the output signals from each storage device; 230 is a D/D converter for converting the digital signal from switch 220 back into an analog signal.
A functional block (hereinafter referred to as D/A) including an A converter and a filter that removes unnecessary high-frequency components from the converted signal.
Converter 230) and 240 are synchronization signal adding circuits that add a synchronization signal to the signal from the D/H converter 230.

The operation of such a circuit configuration will be explained next.

Analog luminance signal Y and analog color difference signals Cw and CN
are converted into digital signals by A/D converters 201, 202 and 203, respectively, and stored in a storage device 211゜2.
12 and 213. Figure 4 shows color difference signal C
During the time allocated to W and CN and the luminance signal Y,
Switch 220 connects storage devices 211, 212 and 213
The outputs from the 111/8 converter 230 are sequentially inputted to the 111/8 converter 230.

First, the switch 220 inputs the output signal of the storage device 212 in which the color difference signal "Co" is stored to the D/A converter 230, and one horizontal pixel in the storage device 212 is inputted to the D/A converter 230 at the first 174 times of one horizontal scanning period. The column signals are read and D/A converted. Next, the switch 220 inputs the output signal of the storage device 213 in which the color difference signal CN is stored to the D/A converter 230.
The signal of one horizontal pixel column within 3 is read out and converted to D/8.

Next, the switch 220 inputs the output signal of the storage device 211 in which the luminance signal Y is stored to the D converter 230.
During the remaining 172 hours of the horizontal scanning period, the signal of one horizontal pixel column in the storage device 211 is read out and D/A converted. Finally, in the synchronization signal addition circuit 240, a synchronization signal is added to the signals sequentially input from the D/A converter 230 to form a Tel signal.7 [Problems to be solved by the invention] However, the above In such a Tel signal forming circuit, the luminance signal Y and the color difference signals Cw and CN must be stored, and the storage device and A/
D, D/A converter, etc. are required, and the circuit configuration becomes complicated.

An object of the present invention is to solve the above-mentioned problems in an imaging device that generates a Tel signal, and to extremely easily transmit a Tel signal.
An object of the present invention is to provide an imaging device that can obtain signals.

[Means for Solving the Problems] The present invention provides a nondestructive image sensor in which a plurality of pixels are arranged in a matrix, and a signal charge is applied to each pixel of the image sensor at least twice in one horizontal scan per row. scanning means for scanning horizontally and vertically so as to read out the information; and means for forming a time division multiplexed signal by creating different information signals from each of at least two read signals obtained by the scanning means in one horizontal scanning period. Equipped with.

[Function] According to the present invention, an image sensor in which pixels are arranged in a matrix is used, and the signal charges of all pixels in one row are sequentially read out twice or more within one horizontal scanning period, and each readout is performed twice or more. The signal is processed as, for example, a color difference signal or a luminance signal and sent out.

[Example] An embodiment of the present invention is shown in FIGS. 1 and 3. FIG.

FIG. 1 shows the configuration of an image sensor and its peripheral circuitry, and FIG. 5 shows the configuration of a three-chip color camera using three image sensors shown in FIG.

First, FIG. 3 will be explained. Note that the number of pixels in the image sensor is determined so as to obtain sufficient resolution both horizontally and vertically, but in this example, for the sake of explanation, 4 rows and 4 pixels are used.
column. 351~354.361~364,371~
374, 381 to 384 are pixels (for example, composed of a transistor and its base capacitance) that can be read out non-destructively and constitute an image sensor, and are arranged in a matrix. The collector of each pixel transistor is connected to a suitable power supply (not shown), and the emitter is connected to each vertical line v1 to v4 for reading out the signal charge accumulated in its base capacitance.
are connected to each column.

310 is a shift register for horizontally reading and scanning each pixel of the image sensor.

320 is a shift register for vertical readout scanning, and the bit output is shifted every time the horizontal synchronizing signal fH is input to the terminal 301, and each bit output is shifted at the timing shown in FIG. Four readout pulses a to d are output within one horizontal scanning period, and the output of each bit is applied to the base of each pixel of the image sensor for each row via each horizontal line H4.

331 to 334 are switch transistors involved in horizontal scanning, which transfer signal charges read out from each pixel onto each vertical line v1 to v4 to an output terminal 3o9 based on each bit output from the shift register 310. Send out sequentially.

391 to 394 are capacitors for temporarily storing signal charges read out from the pixels to each vertical line.

Transistors 341 to 344 are connected to each vertical line, and discharge the signal charges accumulated in each capacitor 391 to 394 to set them in a reset state.

Reference numeral 308 applies four reset pulses LX every horizontal scanning period to the gates of each of the transistors 341 to 344 at the timing shown in FIG. 2 in relation to the horizontal synchronizing signal f□.
, reset signal application terminal for applying LZ, 399
is a load resistance for the signal charges read out to the output terminal 309, and applies a voltage corresponding to the signal charges to the terminal 309.

301 is an application terminal for the horizontal synchronization frequency signal fH, 302.
303 and 304 are multiplier circuits for the horizontal synchronization frequency signal from the terminal 3θl, and 305 is a selection switch for selecting the output of each multiplier circuit and applying it to the clock input terminal of the horizontal shift register 310.

Reading out signal charges from the image sensor in the above configuration is performed as follows.

Pixels 351-354.361-364,3 in response to light
It is assumed that an amount of charge corresponding to the amount of light is accumulated in the base capacitors 71 to 374 and 381 to 384.

Signal charges are read out from each pixel in the first row of the image sensor three times in one horizontal scanning period as follows.

During the first reading, the horizontal synchronization (frequency) signal fH input to the terminal 301 is transmitted to the first multiplier 30.
2 is multiplied by N, and the second multiplier 303 is multiplied by N1, as shown in FIG. do. At the same time, vertical shift register 32
1 horizontal opening clock is applied from the terminal 301 to the 0 clock terminal, the output of the first bit 321 becomes "1", and the rest remain "0".

First, the reset pulse W is applied to the transistors 341 to 343.
is applied to the gate of each vertical line capacitor 391~
Sweep out the charge remaining in 394. Next, the base of each pixel 351 to 354 in the first row is biased by the readout pulse a, the transistor constituting the pixel is turned on, and a current (signal charge) corresponding to the charge accumulated in the base capacitance is applied to each vertical Each capacitor 391~
394 (note that the charges accumulated in the base capacitance are not discharged, i.e., non-destructive). Then, each bit output N-N1.fn of the horizontal shift register 310 causes the switch transistors 331, 332, 333, . 3
By sequentially closing the terminals 34, the signal charges accumulated in the capacitors 391, 392, 393, and 394 corresponding to the pixels 351, 352, 353, and 354 in the first row are sequentially read out to the terminal 309 (readout in FIG. A) of the signals 402.

In the second readout, the residual charges in the capacitors 391 to 394 are first wiped out by the second reset pulse X, and the signal charges of the pixels 351 to 354 are accumulated in the capacitors 391 to 394 by the read pulse b. Then, the horizontal synchronizing signal f)I is multiplied by N in the first multiplier 302, and
A signal with a lock frequency N-N2·fH as shown in FIG. Each bit output N-82 of the shift register 310
・The transistors 331 to 334 are made conductive in sequence at f, and the signal charges accumulated in the capacitors 391 to 394 are sequentially transferred to the terminal 3.
09 (B of the read signal 402 in FIG. 2)
. Similarly, the third readout is performed by wiping out the residual charges in the capacitors 391 to 394 by the third reset pulse C;
After the signal charge is accumulated in the capacitors 391 to 394 by the readout pulse y, the horizontal synchronizing signal fH is multiplied by the first
.

The signal of frequency N-fH multiplied by N by the switch 302 is sent to the switch 3.
05 and input to the clock input terminal of the horizontal shift register 310. Each bit output N'fh of the shift register 310 sequentially turns on the transistors 331 to 334, and transfers the accumulated signal charges to the capacitors 391 to 394 to the terminal 3.
09 (C of read signal 402 in FIG. 2)
.

Then, due to the read pulse d and the reset pulse Z that occur simultaneously, the charge accumulated in the base capacitance of the transistor constituting each pixel in the first row is discharged, and each pixel is restored to its initial state. That is, by applying the readout pulse d to the base of the transistor constituting each pixel in the first row and at the same time applying the reset pulse 2 to the terminal 308 to ground each vertical line, the voltage is accumulated in the base capacitance of each transistor. Forcibly discharge the signal charge.

Next, when the next horizontal synchronization clock is applied to the vertical shift register 320, "1" is transferred to the second bit 322, and all remaining bits are "O", so the second row The signal charges of the eye pixels 361 to 36jl are read out to the terminal 309. Similarly, each time one horizontal opening clock is applied to the terminal 301, the read pixels advance one line at a time, and vertical scanning is performed.

Therefore, as described above, the signal charges of pixels in one row are read out three times in one horizontal scanning period, and the first readout signal (A in FIG. 2) is transferred to the TC shown in FIG.
The TC shown in FIG. 1 is assigned to the first color difference signal Cw101 of the I signal, and the second readout signal (FIG. 2B) is assigned to the first color difference signal Cw101 of the I signal.
The second color difference signal C of the I signal is assigned to 102, and the third readout signal (C in FIG. 2) is assigned to the second color difference signal C, 102 in FIG.
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FIG. 3 shows an embodiment in which the above-described configuration is applied to a three-chip color camera.

In the figure, 501 is a lens, and 502 is a lens 501.
503 to 505 are non-destructively readable imaging elements provided at each output end of the color separation prism 502, and 506 to 508 are each of the elements 503 to 505.
Red (R) by processing the imaging signal from.

a signal processing circuit that outputs green (G) and blue (B) signals, respectively;
509 is a matrix circuit that generates color difference signals Cw, Cs and luminance signal Y based on signals from each signal processing circuit.

513 is the color difference signal Cw at the timing of TCI signal formation;
A selection circuit selects and outputs one of CN and luminance signal Y, 514 is a synchronization signal addition circuit that adds a synchronization signal to the signal from selection circuit 513, and 515 is an image sensor drive circuit, which is similar to the one described above. Each image sensor is driven at such timing, and the selection circuit 513 is controlled at the timing of TCI signal formation.

Next, the operation of this embodiment will be explained.

Light incident from a lens 501 is separated into three primary colors of light, R, G, and B, by a color separation prism 502, and photoelectrically converted by image pickup elements 503 to 505 at an imaging position.

This image sensor is driven by a drive circuit 515 to read out the signal charge of each pixel. The method for reading signal charges from the image sensor is as explained using FIGS. 1 and 2. The output signal of the image sensor is divided into n, G, and a by a signal processing circuit 5.
After processing in steps 06 to 508, a matrix circuit 509 generates color difference signals CW and CN and a luminance signal Y. As described above, since reading is performed three times within one horizontal scanning period, the color difference signal C8+CN and the luminance signal Y are generated three times. The drive circuit 515 controls the selection switch 513 in accordance with the allocated time shown in FIG. The same circuit 514 adds a synchronization signal to the input signal to create a TCI signal.

The embodiment described above corresponds to the TCI signal shown in FIG.
CW signal alternately every horizontal scanning period.
Alternatively, for a color difference line sequential TCI signal that sends CN, the following procedure may be performed. That is, for example, in FIG. 3, signals of pixels in one row are read out twice from each image sensor in one horizontal scanning period. The selection switch 513 may be switched so that a combination of Cw and Y or CN and Y is multiplexed for each horizontal period among the color difference signals C, , C and the luminance signal Y generated by the matrix circuit 509. .

Moreover, although the case where the present invention is applied to a three-chip color camera is shown as an example, it is clear that the present invention can also be used for a single-chip color camera. Furthermore, in the embodiment shown in FIG. 1, an image sensor that can be read out non-destructively is of a type that performs photoelectric conversion in the base region or gate region of the transistor.
Of course, it is also possible to use an element called nDevice.

[Effects of the invention] As explained above, according to the present invention, it is possible to achieve (A) with a simple configuration.
/D, D/A converter and storage device are not required) A time division multiplexed video signal can be obtained.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of an imaging device according to the present invention, FIG. 2 is an operation waveform diagram of the embodiment shown in FIG. 1, and FIG.
Figures showing another embodiment of the present invention applied to a plate color camera; Figure 4 is a waveform diagram of the TCI signal; Figure 5 is a waveform diagram of the luminance signal Y and color difference signals Cw and CN to TC
(2) It is a block diagram of a conventional device for converting into a signal. Figure 4

Claims (1)

[Claims] A non-destructive image sensor in which a plurality of pixels are arranged in a matrix; A scanning device that performs vertical scanning; and a device that generates different information signals from each of at least two read signals obtained by the scanning device in one horizontal scanning period to form a time division multiplexed signal. Characteristic imaging device.