JPH04257171A - Image pickup device - Google Patents

Abstract

PURPOSE:To obtain faster-speed shutter operation. CONSTITUTION:The image pickup device includes a photosensitive part 8 which is a photoelectric conversion cell array, two systems of vertical transfer registers 2 and 3 and two systems of horizontal transfer registers 4 and 5 which are provided in relation with the photosensitive part 8, and a switch circuit 6 which alternates and outputs the output signals of said registers 4 and 5 from the device at each 1/2 horizontal scanning period; and the readout speeds of charges of the image pickup device, i.e. shutter speed is reduced to a half as fast as before.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device, and more particularly to an imaging device having a high-speed shutter function.

0002

[Prior Art] In general, the high-speed shutter function of a video camera does not mechanically limit the light incident on the optical system, but uses an electronic shutter function by controlling the readout timing of the charge signal of the image pickup device installed therein. This is realized by

FIG. 5 is a schematic diagram showing the configuration of an imaging device mounted on a conventional video camera.

In the figure, the imaging device is a two-dimensional image sensor (solid-state imaging device) that captures a two-dimensional image without mechanical scanning. This is configured to detect a two-dimensional image by performing electronic scanning by transferring the charge of the image of the photographed object. Specifically, the imaging device includes a photosensitive section 15 and a storage section 16. The photosensitive section 15 includes two-dimensionally arranged photodiodes 1 that accumulate charges according to the amount of received light, and is further connected in parallel to the photodiode array via a charge transfer transistor (not shown). Contains vertical transfer register 12. The vertical transfer register 12 is a CCD
(Abbreviation for Charge Coupled Device) It is configured to include a shift register, and the charges read out here are transferred in series.

The accumulation section 16 includes the vertical transfer register 12, and the charges accumulated here are sequentially transferred in parallel to the horizontal transfer register 13 via the register 12. In response, the horizontal transfer register 13 sequentially transfers the applied signal charge horizontally at high speed to the output side using, for example, a two-phase drive method, and provides the signal charge to the output circuit 14. Output circuit 14
converts the applied charge into a voltage signal and outputs it to the outside while amplifying it. The voltage signal output from the output circuit 14 is applied to a video signal processing circuit connected to the next stage (not shown).

FIGS. 6(a) to 6(h) are timing charts for explaining the charge transfer drive timing when the electronic shutter function is operated in the image pickup apparatus shown in FIG. 5 above.

FIG. 6(a) shows a vertical blanking pulse VD whose period is 1/60 second.

FIG. 6(b) shows the accumulated charge PE1 photoelectrically converted and accumulated in each photodiode 1.
Figure (c) shows a read pulse RP for performing a read operation of the accumulated charge PE1. FIG. 6(d) shows a sweep pulse HP1 for sweeping away the charges photoelectrically converted by each photodiode 1 onto a substrate on which the imaging device is integrated. The pulse HP1 is supplied to the device every horizontal scanning period (every 1/15734 seconds).

FIG. 6(e) shows a horizontal blanking pulse HD whose period is 1/15734 seconds.

FIG. 6(f) shows the horizontal transfer pulse HT. This horizontal transfer pulse HT is applied to the horizontal transfer register 13.
This is a charge transfer pulse for sequentially horizontally transferring signal charges transferred in parallel from the vertical transfer register 12 to the output circuit 14, and is synchronized with the pulse HD.

FIGS. 6(g) and 6(h) show horizontal drive pulses HT1 and HT2 forming the horizontal transfer pulse HT shown in FIG. 6(f). Since the pulses HT1 and HT2 are alternately applied as predetermined voltage pulses to each CCD constituting the horizontal transfer register 13, the signal charges are not mixed in the horizontal transfer register 13 and are sequentially transferred toward the output circuit 14. .

The horizontal axis of each of these signals indicates the passage of time, and the vertical axis indicates each signal level. Note that the signal RP
, HP1, HD, and HT are obtained by generating the pulse VD by a pulse generation circuit (not shown) and then frequency-dividing the pulse VD, and are supplied to the imaging apparatus.

During imaging, charge is accumulated in each photodiode 1 every high-speed shutter time, that is, every 1/60 second, as shown in FIG. 6(b). In other words,
The accumulated charge PE1 shown in the figure is accumulated during the 1/60 second, for example, 1/100 second, and the remaining charge (1/60-1/1
The charges obtained by conversion in 00) seconds are not accumulated and are sequentially discarded to the substrate by application of a sweep pulse HP1. Therefore, the charge corresponding to the high-speed shutter time is obtained as the accumulated charge PE1, and this charge PE1 is read out to the vertical transfer register 12 adjacent to each photodiode 1 via a transfer gate section (not shown) by the readout pulse RP.

The charges read into the vertical transfer register 12 are sequentially vertically transferred toward the storage section 16 at high speed. Therefore, the charges are given to the horizontal transfer register 13 in parallel in accordance with the video period (1/60 seconds), and are transferred horizontally at high speed by a two-phase drive method using, for example, horizontal transfer pulses HT1 and HT2. and output circuit 14
can be given to The output circuit 14 converts the applied charge into a voltage signal, amplifies it, and provides it to the subsequent signal processing circuits.

As described above, the high-speed shutter function of conventional imaging devices is achieved by alternately sweeping and accumulating the charges obtained through photoelectric conversion during the shutter period (1/60 seconds). A different video signal is obtained for each shutter cycle. Therefore, one frame screen of the video signal is composed of two field screens (1/60 second x 2),
It becomes possible to clearly capture images of subjects moving at high speed without deteriorating resolution.

[0016]

[Problems to be Solved by the Invention] In conventional imaging devices, as mentioned above, high-speed shutter operation is performed every 1/60 seconds, so it is possible to capture an image of a subject moving at high speed without deteriorating its resolution. However, it has been difficult for the photographer to capture a desired subject image in a timely manner. For example, if you are trying to capture the moment when the ball makes an impact in golf, etc., it is sufficient that the moment of impact coincides with the above-mentioned 1/60 second timing, but if it does not match, the moment of impact will be missed. I decided to put it away. In other words, the conventional imaging device has the above 1/
When capturing an image of a subject that moves faster than 60 seconds, there is a problem in that not only the continuity of the movement becomes unnatural, but also the timing to capture the subject image is missed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image pickup apparatus having a high-speed shutter function that allows faster shutter operation.

[0018]

[Means for Solving the Problems] An imaging device according to the present invention has one or more photoelectric conversion cells arranged in a matrix along the horizontal and vertical directions, and converts a projected image of a subject into electrical charges. a photoelectric conversion cell array for converting and storing a photoelectric conversion cell array; a first vertical transfer means adjacent to the other side of each of the vertical cell arrays and read from each cell in response to a second read signal following the first read signal supplied from the outside; a second vertical transfer means that sequentially transfers the charges output from the first vertical transfer means in the horizontal direction; a first horizontal transfer means that sequentially transfers the charges output from the first vertical transfer means in the horizontal direction; 2nd stage that sequentially transfers the charges in the horizontal direction
The horizontal transfer means and the switching means input the charge signals outputted from the first and second horizontal transfer means and alternately switch and output the signals every 1/2 horizontal scanning period accordingly.

[0019]

[Operation] The imaging device according to the present invention is constructed as described above, and the charges converted and accumulated in the photoelectric conversion cell array are read out to the first and second vertical transfer means by the first and second read signals. , and are sequentially transferred in the vertical direction. Next, the charge is sequentially transferred in the horizontal direction via the first and second horizontal transfer means, and the switching means inputs the charge signal output from the first and second horizontal transfer means, and accordingly Since the output is alternately switched and output every two horizontal scanning periods, it is possible to read out the subject image obtained by forming the image in the photoelectric conversion cell array at high speed, and this enables high-speed shutter operation in the imaging device. Can be provided.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of an imaging device according to an embodiment of the present invention. In the figure, the imaging device includes a photosensitive section 8, a storage section 9, horizontal transfer registers 4 and 5, as well as a switch circuit 6, an output circuit 1, as in the conventional case.
0 and 11 and an output section 7. The photosensitive section 8 further includes a plurality of photodiodes 1 arranged two-dimensionally to form a light-receiving surface, and a vertical transfer register 2 and a high-speed transfer register 3 are connected adjacently to each column of the photodiodes 1. Ru. The vertical transfer register 2 and the high speed vertical transfer register 3 are transferred with charges accumulated therein from one column of adjacent photodiodes. The horizontal transfer registers 4 and 5 are provided with charges transferred in parallel from the vertical transfer register 2 and the high-speed vertical transfer register 3, respectively. Each of the transfer registers 2 to 5 includes a CCD array, and the charge transfer function of the CCD is utilized for the scanning function of an image sensor that detects a two-dimensional image.

The output circuits 10 and 11 sequentially convert charges transferred from the horizontal transfer registers 4 and 5 connected to the preceding stage into voltages and output them. Both of these output voltages are applied to the input side of the switch circuit 6 at the next stage.

The switch circuit 6 includes signal input terminals a and b, and the horizontal transfer register 4 and the output circuit 1
0 is inputted through the terminal a, and a voltage signal applied through the horizontal transfer register 5 and output circuit 11 is inputted through the terminal b. In response to the signal level of the switching signal CH applied from the outside, the switch circuit 6 switches its signal input side to either terminal a or b, and outputs the voltage signal applied to the switched terminal. It operates so as to derive the signal and provide it to the output section 7 at the next stage.

The output section 7 inputs the voltage signal applied from the switch circuit 6 connected at the previous stage, amplifies it accordingly, and supplies it to a signal processing circuit for a video signal (not shown) connected thereafter.

As described above, the signal charges obtained by the photoelectric conversion cells in the photosensitive section 8 are transferred to the readout pulses RPA and R.
In response to the supply of PB, the data is read out to the vertical transfer register 2 and the high-speed vertical transfer register 3, and accordingly, the data is sequentially transferred in the vertical direction. Therefore, the charge transferred to the vertical transfer register 2 is transferred to the horizontal transfer register 4, and the signal charge in the high-speed vertical transfer register 3 is further transferred to the next stage storage section 9 in response to the supply of the high-speed transfer pulse TP. Ru. The charges transferred to the storage section 9 are then transferred to the horizontal transfer register 5. Horizontal transfer registers 4 and 5
is supplied with horizontal transfer pulses FT and CT, and accordingly sequentially transfers charges in the horizontal direction using a two-phase drive method, and supplies them to the switch circuit 6 via output circuits 10 and 11 provided in the output stage. Since the input side of the switch circuit 6 is switched in response to the switching signal CH, the signal charges in the photosensitive section 8 and the signal charges in the storage section 9 are alternately outputted to the outside. Therefore, according to the imaging device shown in FIG. 1, it is possible to obtain twice as much signal amount per unit time as compared to the conventional imaging device shown in FIG. 5 described above.

FIGS. 2(a) to 2(d) are diagrams for explaining the high-speed shutter function operation of an image pickup apparatus according to an embodiment of the present invention.

FIGS. 3(a) to 3(f) are timing charts for explaining the charge transfer drive timing when the high-speed shutter function of the imaging device shown in FIGS. 2(a) to 2(d) is operated. It is a diagram.

FIG. 3(a) shows a vertical blanking pulse VD whose period is 1/60 second.

FIG. 3(b) shows the accumulated charge PE photoelectrically converted and accumulated in each photodiode 1, and FIGS. 3(c) and 3(e) show the accumulated charge PE when the readout operation of the accumulated charge PE is performed. The read pulses RPA and RPB are shown for readout. Further, FIG. 3(d) shows a sweep pulse HP for sweeping away the charges obtained by photoelectric conversion in each photodiode 1 onto the substrate on which the imaging device is integrated. Furthermore, FIG. 3(f) shows the high-speed vertical transfer register 3.
shows a high-speed transfer pulse TP for sequentially transferring the charges read out and applied from one row of adjacent photodiodes to the storage section 9 connected to the next stage at high speed.

The horizontal axis direction of each of the above-mentioned signals indicates the passage of time, and the vertical axis direction indicates each signal level.

Note that the signals RPA, RPB, HP, and TP are obtained by frequency-dividing the pulse VD generated by a pulse generation circuit (not shown), and are supplied to this imaging apparatus.

FIGS. 4(a) to 4(i) are timing charts for explaining the charge transfer in the horizontal transfer registers 4 and 5 and the switching operation of the switch circuit 6 in the image pickup device according to an embodiment of the present invention. It is.

FIG. 4(a) shows the horizontal blanking pulse H.
D, and its period is 1/15734 seconds.

FIG. 4(b) shows the switching signal CH supplied to the switch circuit 6, and shows the horizontal blanking pulse HD.
Sync.

FIG. 4(c) shows a horizontal transfer pulse FT for charge transfer supplied to the horizontal transfer register 4. The horizontal transfer pulse FT is a charge transfer pulse for sequentially horizontally transferring signal charges transferred in parallel from the vertical transfer register 2 to the horizontal transfer register 4 in the direction of the output circuit 10, and the level of the switching signal CH is Only the high period is supplied to the register 4.

FIG. 4(d) shows a horizontal transfer pulse CT supplied to the horizontal transfer register 5 for charge transfer. The horizontal transfer pulse CT is a charge transfer pulse for sequentially horizontally transferring signal charges transferred in parallel from the high-speed vertical transfer register 3 to the horizontal transfer register 5 in the direction of the output circuit 11, and The signal is supplied to the register 5 only during the level low period.

FIG. 4(e) shows a signal CH1 obtained by enlarging the switching signal CH of FIG. 4(b) in a period E.

FIGS. 4(f) and 4(g) show two-phase horizontal driving pulses FT1 and FT2 constituting the horizontal transfer pulse FT shown in FIG. 4(c). Each CCD constituting the horizontal transfer register 4 receives the pulses FT1 and F.
Since T2 is applied alternately as a predetermined voltage pulse,
In the horizontal transfer register 4, charges are sequentially horizontally transferred toward the output circuit 10 without mixing.

FIGS. 4(h) and 4(i) show two-phase horizontal driving pulses CT1 and CT2 constituting the horizontal transfer pulse CT shown in FIG. 4(d). Each CCD constituting the horizontal transfer register 5 receives the pulses CT1 and C
Since T2 is alternately supplied as predetermined voltage pulses,
In the horizontal transfer register 5, the charges are sequentially horizontally transferred toward the output circuit 11 without being mixed.

In each of FIGS. 4(a) to (i), the vertical axis indicates each signal level, and the horizontal axis indicates elapsed time.

Next, regarding the high-speed shutter function operation of the imaging device according to this embodiment, FIGS. 2(a) to (d) and 3.
Figures (a) to (f) and Figures 4 (a) to (i)
Explain with reference to.

First, the reflected light of the subject image is transmitted to the photosensitive section 8.
is incident on the photodiode 1 and photoelectrically converted in each photodiode 1,
The accumulated charge PE shown in FIG. 3(b) is obtained.

Accumulated charge P in each photodiode 1
In order to read E to the adjacent high speed vertical transfer register 3,
For example, pulse ■ of the read pulse RPB in FIG. 3(e)
is applied to the gate of a transistor (not shown) connecting each photodiode 1 and resistor 3, and each transistor becomes conductive accordingly. As a result, the accumulated charge PE in each photodiode 1 is transferred to the adjacent high-speed vertical transfer register 3 via the conductive transistor.
The data is transferred to and read out (see FIG. 2(a)).

After the pulse RPB is supplied, the sweep pulse HP shown in FIG. 3(d) is supplied to each photodiode 1, and the charges photoelectrically converted and stored are sequentially swept away to the substrate. Next, the accumulated charge PE is shown in Fig. 3 (
For example, pulse (2) of the read pulse RPA (c) acts in the same manner as pulse (2), and is transferred to the vertical transfer register 2 and read out (see FIG. 2(b)). The read pulse R
Along with the supply of the pulse ■ of PA, for example, the pulse ■ of the high-speed transfer pulse TP shown in FIG. is transferred at high speed to the storage unit 9 of (
(See Figure 2(c)).

During the period until the next high-speed transfer pulse TP is supplied, for example, during the period (f) in FIG. At the same time, the charges that had been transferred to vertical transfer register 2 and storage section 9 are transferred and read out in parallel to horizontal transfer registers 4 and 5, respectively. Accordingly, horizontal transfer registers 4 and 5 are
The charges transferred in parallel from the vertical transfer registers 2 and 3 are horizontally transferred to the output circuits 10 and 11 sequentially by a two-phase drive method (see FIG. 2(d)).

Horizontal transfer of charges in the horizontal transfer registers 4 and 5 is performed by a two-phase driving method using horizontal transfer pulses FT and CT shown in FIGS. 4(c) and 4(d). That is, in the first half of one horizontal scanning period in FIG. 4(a), the horizontal driving pulses FT1 and FT2 are
is alternately applied as a pulse to each CCD of the horizontal transfer register 4, and the charges are sequentially horizontally transferred toward the output circuit 10. Further, in the latter half of one horizontal scanning period in FIG. 4(a), horizontal driving pulses CT1 and CT2 are alternately applied to each CCD of the horizontal transfer register 5, and the charges are sequentially horizontally transferred toward the output circuit 11. be done.

Therefore, the output circuits 10 and 11 are supplied with charge signals having different contents obtained by dividing one horizontal scanning period into two, and the input side is switched. In response, output circuits 10 and 11 sequentially convert the applied charges into voltage signals and apply them to terminals a and b of switch circuit 6, respectively.

Now, the switching signal CH is stably applied to the switch circuit 6 at the period shown in FIG. 4(b) or (e). That is, during the high level period of the switching signal CH, the signal input side of the switch circuit 6 is switched to the terminal a side, and during the low level period of the switching signal CH, the signal input side of the switch circuit 6 is switched to the terminal b side. Therefore, the signal input side of the switch circuit 6 is alternately switched to the terminal a side and the terminal b side in synchronization with the switching signal CH, so that the signal obtained from the photosensitive section 8 and the signal obtained from the storage section 9 are transferred at high speed. It operates so that the output is output alternately and alternately. The output signal of the switch circuit 6 is applied to the output section 7 of the next stage, where it is further amplified and applied to the signal processing section of the subsequent stage.

[0049] Also in the period (2), as shown in the timing chart of Fig. 3, photoelectric conversion, charge readout, and charge accumulation are performed in parallel, so the above-mentioned Figs. 2 (a) to () The charge reading operation d) is repeated.

As described above, according to this embodiment, the readout pulses RPA and RPB shown in FIGS. 3(c) and 3(e) are applied to each photodiode 1 alternately every (1/240) second.
Since the charge is supplied so as to be read out, a shutter speed four times faster than the conventional shutter speed described above can be obtained.

Note that the supply intervals of the read pulses RPA and RPB are not specified by the numerical values in this embodiment, but can be set variably.

[0052]

According to the imaging device according to the present invention, the charges converted and accumulated in the photoelectric conversion cell array are first read out to the first and second vertical transfer means by the first and second read signals, and The signal is then transferred in the vertical direction, and subsequently transferred in the horizontal direction via the first and second horizontal transfer means. The switching means inputs charge signals given from the first and second horizontal transfer means and operates to alternately switch and output them every 1/2 horizontal scanning period, so that the charge transfer speed is lower than that of the conventional one. A high-speed shutter operation set to twice or more can be obtained.

Furthermore, by variably controlling the supply interval of the first and second readout signals, it is possible to arbitrarily variably control the readout speed of charges from the photoelectric conversion cell array, that is, the electronic shutter speed of the imaging device. There is.

[Brief explanation of the drawing]

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

FIGS. 2(a) to 2(d) are schematic diagrams for explaining the high-speed shutter function operation of an imaging device according to an embodiment of the present invention.

3(a) to 3(f) are timing charts for explaining the charge transfer drive timing when the high-speed shutter function of the imaging device shown in FIGS. 2(a) to 2(d) is operated; FIG. be.

FIGS. 4(a) to 4(i) are timing charts for explaining charge transfer in a horizontal transfer register and switching operation of a switch circuit of an imaging device according to an embodiment of the present invention;

FIG. 5 is a schematic diagram showing the configuration of an imaging device installed in a conventional video camera.

6A to 6H are timing charts for explaining the charge transfer drive timing when the electronic shutter function is operated in the imaging device shown in FIG. 5; FIG.

[Explanation of symbols]

1 Photodiode 2 Vertical transfer register 3 High-speed vertical transfer register 4 and 5 Horizontal transfer register 6 Switch circuit 8 Photosensitive part 9 Accumulation section CH switching signal RPA and RPB read pulse TP High-speed transfer pulse FT and CT horizontal transfer pulse In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A photoelectric conversion cell array having one or more photoelectric conversion cells arranged in a matrix along the horizontal and vertical directions, for converting and accumulating a projected image of a subject in the form of electric charge. , first vertical transfer means adjacent to one side of each of the vertical cell arrays and sequentially transferring charges read from each cell in the vertical direction in response to a first read signal supplied from the outside; , which is adjacent to the other side of each of the vertical cell arrays and sequentially transfers charges read from the cells in the vertical direction in response to a second read signal following the first read signal supplied from the outside. a second vertical transfer means for sequentially transferring the charge output from the first vertical transfer means in the horizontal direction; and a first horizontal transfer means for sequentially transferring the charge output from the second vertical transfer means in the horizontal direction. a second horizontal transfer means, and a switching means that inputs charge signals output from the first and second horizontal transfer means and alternately switches and outputs them every 1/2 horizontal scanning period according to the input charge signals. Imaging device.