JPH01165274A - Device for driving solid-state image pickup element - Google Patents

Abstract

PURPOSE:To make shutter speed continuously changeable by providing a video exposure control means which decides the exposure starting timing at each field by counting clock signals. CONSTITUTION:A video exposure control means 36 generates trigger signals for deciding the exposure starting timing at each field by counting clock signals in a horizontal scanning period. A video output driving pulse generating means 16 controls the shutter speed at each field of a solid-state image pickup element 1 by using the trigger signals as a reference. Therefore, the shutter speed can be changed continuously when a solid-state image pickup element driving device 7 which gives driving pulses to the solid-state image pickup element 1 drives the element 1 in a video mode.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a drive device that creates drive pulses for a solid-state image sensor having a still image shooting mode and a video output mode. This invention relates to a solid-state J-image element driving device that can be controlled.

(Background of the Invention) In recent years, still video cameras that combine a solid-state image carrier such as a COD and a recording III for recording on a floppy disk (video floppy) have been put into practical use. Unlike conventional film cameras, such still video cameras do not require development or printing processes. Then, by playing back the removed image on the playback device, the TV receiver B4
It has the advantage that it can be confirmed on a screen at the beach, etc., and that the image can be sent as an electrical signal to a remote location.

FIG. 3 is a block diagram showing the configuration of this type of solid-state image sensor (FIT-CCD). In the figure, 1 is a solid-state image carrier, 2 is a photosensitive section that generates charges according to the brightness of the subject, and 3 is a vertical transfer section that temporarily accumulates the charges generated in the photosensitive section 2 and transfers them in the vertical direction. , 4 is a sweep drain for discarding unnecessary charges, 5 is a storage section that stores the charges from the vertical transfer section 3, and 6 is a horizontal transfer section that shifts the charges from the storage section 5 in the horizontal direction and outputs it as an image signal. It is.

FIG. 4 is a timing chart of drive pulses applied to the solid-state Wi image element 1. As shown in FIG. In the figure, φv1 to φ
■4 is a pulse for driving the vertical transfer section 3, φA~φ
S4 is a pulse for driving the storage section 5.

At the start of exposure, the 13th G pulse moves unnecessary charges that have been present in the photosensitive section 2 to the vertical transfer section 3. After this, the photosensitive section 2 continues to generate charges according to the image information. During this time, unnecessary charges are swept out and dumped into the drain 4 by a high-speed transfer pulse. Once the predetermined exposure time has elapsed,
The charges generated in the photosensitive section are transferred to the vertical transfer section 3 by the 28th G pulse. This charge is transferred to the storage section 5 by the next high-speed transfer pulse. The storage unit 5 stores the transferred charges as analog quantities. The charges transferred from the photosensitive area are no longer affected by external light, and the image information at the time of the end of exposure is stored.

This charge is transferred to the horizontal transfer section 6 by the readout pulse, and outputted from the horizontal transfer section 6 as an image signal.

(Problems to be Solved by the Invention) In order to make the exposure time of the solid-state imaging device variable as described above, it is necessary to change the interval between the 18th G pulse and the 23rd G pulse.

However, in the video mode, it is difficult to continuously change the exposure time with a simple circuit configuration.

The present invention has been made in view of the above problems, and its object is to solve the problem of solid matter! An object of the present invention is to realize a solid-state image element driving device that can continuously change the shutter speed when driving an I@ element in video mode.

(Means for Solving the Problems) The present invention, which solves the above problems, generates and supplies driving pulses for driving a solid-state image element having a photosensitive section and a storage section, and whose exposure time is variable. A solid-state image sensor driving device, comprising: a clock signal generating means for generating a reference clock signal; a still image capturing drive pulse generating means for generating a still image solid state drive pulse based on the clock signal; a video output drive pulse generating means for generating drive pulses for video output based on the clock signal and the θ trigger signal; and a video output drive pulse generating means for generating a trigger signal for determining the exposure start timing for each field when outputting the video. and an exposure control means, wherein the video exposure control means is configured to determine the exposure start timing for each field by counting the clock signal.

(Function) The video exposure control means generates a trigger signal for determining the exposure start timing for each field by counting the clock signal of the horizontal scanning period. The video output drive pulse generating means controls the shutter speed of each field of the solid-state image carrier based on the trigger signal.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration example of an embodiment of the present invention. In the figure, 1 is a solid-state image carrier that performs photoelectric conversion;
2 is a photosensitive part that generates a charge according to the brightness of the subject; 3
4 is a vertical transfer section that temporarily accumulates the charges generated in the photosensitive section 2 and transfers them in the vertical direction, and 4 is an L for discarding unnecessary charges.
5 is a storage section that stores the charge from the vertical transfer section 3; and 6 is a horizontal transfer section that shifts the charge from the storage section 5 in the horizontal direction and outputs it as an image signal.

Although only one row of photosensitive sections and vertical transfer sections is shown here, it is assumed that actually a plurality of rows are provided. Reference numeral 7 denotes a solid-state imager driving device that applies driving pulses to the solid-state imager 1, 8 a signal processing circuit that processes signals photoelectrically converted by the solid-state imager 1, and 9 a signal processing circuit that provides a driving pulse to the solid-state imager 1; a recording device for recording signals on a magnetic disk based on instructions from a system control circuit to be described later;
11 is a shutter button provided in the system control circuit 10; 12 is a system control circuit that gives various instructions to each part; 12 is a system control circuit 10;
13 is a photometry circuit that measures the amount of exposure; 14 is a power supply circuit connected to the system control circuit 10; 15 is an oscillator that generates a reference signal;
16 is a drive pulse generation circuit that generates a drive pulse from a reference signal, 17 is a frequency divider that generates a horizontal scanning frequency (fH) signal from the reference signal, and 18 is a frequency divider that generates a vertical scanning frequency (fH) signal from fH.
19 is a V shifter that creates multiple vertical synchronization signals with different phases from the fV multiplied signal; 20 is a decoder that creates a synchronization signal; 21 is a V counter that creates fV signals with different phases. H shifters 22 and 23 create synchronization signals; HS shifters and HS counters create high-speed transfer (H8) signals for the solid-state image sensor 1 from reference signals; and 24 an HS decoder. In addition, above 1
Terminals 7 to 21 denoted as R, HR, or VR are terminals to which a reset signal, an H reset signal, and a reset signal are applied, respectively. Among these, the reset signal is given when the shutter is opened or closed, and the H reset signal and the V reset signal are given when synchronizing with the recording device 9.

25 is a PG circuit that creates an H reset signal and a reset signal based on the PG double signal when the recording device 9 becomes capable of recording, and 26 is a stable first PG after exposure.
27 is an edge detection circuit that detects the edge of the PG doubled signal that has passed through the gate 26; 28
1 is an H reset generation circuit that generates an H reset signal from the PG double signal edge, and 2 is a V reset generation circuit that generates a V reset signal. In FIG. 1, the connections to which the current day reset signal and (2) reset signal are supplied are omitted, but they are applied to the above-mentioned 17 to 21 as described above. 30 is a still mode shutter control circuit that creates a layerer control signal to control exposure based on the exposure control signal given from the system control circuit in still mode; 31 is a video mode shutter control circuit that controls exposure in video mode; 32 33 is a φ■ system decoder that creates an image area control pulse based on the H8 signal, horizontal synchronization signal, and vertical synchronization signal, and 33 starts and ends exposure to the solid-state image sensor based on the horizontal synchronization signal, vertical synchronization signal, and shutter control signal. 34 is a φSG decoder that creates a signal (SG double signal), and 34 is a φS decoder that creates a storage area control pulse for driving the storage section based on the H8 signal, horizontal synchronization signal, vertical synchronization signal, and shutter control signal. , 35 is a drive circuit which amplifies the output signals of 32, 33 and 33 and supplies them to the solid-state image sensor 1 as a drive signal for the solid-state image sensor, and 36 is a drive circuit that amplifies the output signals of 32, 33 and 33 and supplies them to the solid-state image sensor 1 as a drive signal for the solid-state image sensor. This is a video exposure control circuit that creates a trigger pulse to determine the timing of starting exposure in the field and supplies it to the video mode shutter control circuit.

The still image shooting operation of the above device will be explained below. The system control circuit 1o is waiting for the shutter button 11 to be pressed, and at this time the recording gi! ! 9 is not supplied with power. This is because a lot of power is consumed to rotate the floppy disk. Here, if the shutter button 11 is pressed, the system control circuit 1o supplies power to the recording device 9 to start operation, instructs the photometry circuit 13 to perform photometry, and also sends a trigger signal to the still mode shutter control circuit 30. give. Thereby, the solid-state Wi image element driving device 7 supplies a driving pulse to the solid-state image sensor 1 to start exposure. If it is necessary to cause the strobe to emit light during this exposure, the system control circuit 1o instructs the strobe 12 to emit light. Here, when a predetermined exposure time has elapsed or a proper exposure group has been reached, the driver vJ device 7 gives a pulse to the solid-state image element 1 to end the exposure, and then charges generated by the light reception. A high-speed transfer drive pulse is applied to transfer the data to the storage unit 5. Due to this high-speed transfer drive pulse, charges are accumulated in the storage section 5 until a read signal is applied. The floppy disk of the recording device 9 starts rotating at the same time as exposure starts, but it takes about tens of milliseconds to 100 milliseconds for it to stabilize. When the stable PG double signal is applied to the PG circuit 25, which waits for the PG double signal to become stable, the gate 26 passes only the first PG double signal after exposure, and the edge detection circuit 27 Yang Shu's PG
Detecting the falling edge of the double signal, based on this, the 1'' reset generation circuit 28 generates an H reset (HR) signal, and the 2 reset generation circuit 29 generates a V reset (VR) signal, and the frequency divider 17, V counter 18. v shifter 19. The signal is applied to the decoder 20 and the H shifter 21 to reset it. This reset causes the vertical synchronization signal from the V shifter 19 and the H
The horizontal synchronizing signal from the shifter 21 is a PG multiplied signal whose phase is synchronized. As a result, the signal is generated based on the horizontal and vertical synchronizing signals, and is transmitted from the drive circuit 35 to the solid-state image sensor 1.
The readout drive pulse given to is synchronized with the rotation of the floppy disk of the recording device 9. In this way, the one-parallel element driving device 7 reads out the accumulated charges from the storage section 5. Thereafter, signal processing is performed by the signal processing circuit 8, and recording is performed on the floppy disk of the recording device 9. When this recording is completed, the system control circuit 10 stops supplying power to the recording device 9 and returns to the standby state.

Next, the operation in the video mode will be explained using the timing chart shown in FIG. In video mode,
Without performing the above reset operation, each field ff1(1
/60 seconds), the above φS signal, φ■ signal and φSG
A signal is supplied to the solid-state image sensor. As a result, the signal output from the solid-state image sensor and processed by the signal processing circuit becomes a continuous video signal. At this time, an exposure time instruction signal based on the photometric value measured by the photometric circuit 13 or the shutter speed setting value is sent to the system control circuit 13.
0 to the video exposure control circuit 36. In addition to this, 5BLK pulses shown in FIG. 2(b) are applied to the video exposure control circuit 36. This 5BLK pulse is a horizontal blanking pulse that is not used during the vertical retrace period, and is generated by the decoder 20. The video exposure control circuit 36 counts these 5 BLK pulses in accordance with the instruction signal and determines the exposure start timing for each field. In other words, the timing of the end of exposure (transferring the charge generated in the photosensitive area to the vertical transfer area) within each field is fixed, and the timing of the start of exposure (sweeping away unnecessary charges and starting the accumulation of charge in the photosensitive area) is fixed. By setting the timing to be variable, the exposure time can be varied. FIG. 2(c) shows a video exposure control pulse generated by the video exposure control circuit 36 and applied to the video mode shutter control circuit 30. This pulse is a pulse that rises in accordance with the rise of the vertical synchronizing signal Vo and falls at the timing at which exposure should be started, which is determined by counting 5BLK. The video mode shutter control circuit 31 generates a shutter control pulse that instructs to start exposure in synchronization with the fall timing of the video exposure control pulse. Therefore, the 13th G created by the φSG decoder
Since the pulse generation timing changes with the fall timing of the video exposure control pulse, variable exposure time can be realized. Note that this exposure time can be changed substantially continuously at every interval of the horizontal scanning period (63 μs).

Also, by keeping this video exposure control pulse at L level all the time, the exposure time is maximized (the first SG pulse is generated at the earliest timing of each field), and by keeping it at H level, the exposure time is minimized (the first SG pulse is generated at the earliest timing of each field). The 1SG pulse may occur immediately before the 28th G pulse).

The video exposure control circuit 36 may be built into the solid-state image sensor driving device 7, or may be an external circuit.

(Effects of the Invention) As described above in detail, according to the present invention, in the ando mode, the exposure start timing of each field is made variable and the exposure start timing is determined by counting the timing pulses of the horizontal scanning period. By providing a means for changing the shutter speed, it is possible to realize a solid-state image element driving device that can continuously change the shutter speed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a timing chart during operation of the embodiment of the present invention,
Figure 3 is a block diagram showing an example of the configuration of a solid-state m-image element;
The figure is a timing chart showing the operation of the solid-state ME element. DESCRIPTION OF SYMBOLS 1... Solid-state image sensor 2... Photosensitive part 3... Vertical transfer part 4... Extraction drain 5... Storage part 6... Horizontal transfer part 7... Drive device 8... Signal processing circuit 9...Recording device 10...System control circuit 11...Shutter button 12...S1-Robo 13...Photometering circuit 14
... Power supply circuit 15 ... Oscillator 16 ... Drive pulse generation circuit 17 ... Frequency divider 18 ... V counter 19
...V shifter 20...decoder 21...
H shifter 22...HS shifter 23...l-
IS counter 24...HS decoder 25...
PG circuit 26... Gate 27... Edge detection circuit 28... H reset generation circuit 29... V reset generation circuit 30... Suzuru mode shutter control circuit 31... Video mode shutter control circuit 32 ...φ
■System decoder 33...φSG system decoder 34...φS system decoder 35...Drive circuit 36...Video exposure control circuit Patent applicant
Ceremony: Attorney: Fuji Ijima, 1 person

Claims (1)

[Claims] A solid-state image sensor driving device that includes a photosensitive section and a storage section and generates and supplies drive pulses for driving a solid-state image sensor whose exposure time is variable, the clock signal generating means for generating a reference clock signal. and a still image photographing drive pulse generating means for generating a still image photographing drive pulse based on the clock signal, and a video output generating means for generating a video output driving pulse based on the clock signal and the trigger signal. and a video exposure control means for generating a trigger signal for determining the exposure start timing in each field when outputting the video, the video exposure control means counting the clock signal. What is claimed is: 1. A solid-state image sensor driving device, characterized in that the device is configured to determine exposure start timing in each field.