JPS62166661A - Video camera - Google Patents

Abstract

PURPOSE:To obtain the effect equal to a method that controls the quantity of incident light by a mechanical shutter by controlling a time of accumulation of charge read out from a solid-state image pickup element in a vertical scanning period. CONSTITUTION:A charge accumulation time controlling signal 8 is raised to potential Vb from charge reading pulse of the first field for a time ta. In such a case, Vb is potential that can draw out all charge accumulated in a photoelectric conversion element to an overflow drain. Consequently, the light entered the photoelectric conversion element in the time ta is wholly drawn out to the overflow drain and does not become video signals. Thus, by providing a charge accumulation time controlling signal that controls to draw out all charge to the overflow drain, signal time accumulated in the photoelectric conversion element is controlled electrically, and the element can be used as a high speed video camera.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a video camera using a solid-state image sensor.

2. Description of the Related Art In recent years, special playback such as low-speed playback and frame-by-frame playback has become popular in video decks. For this reason, high-speed video cameras that reduce image blur during special playback are attracting attention.

An example of the conventional high-speed video camera mentioned above will be described below with reference to the drawings.

FIG. 3 is a block diagram showing the overall configuration of a high-speed video camera using a conventional interline charge-coupled solid-state image sensor (hereinafter abbreviated as IL-COD). 1o is a mechanical shutter, 11 is a shutter control unit that operates and controls 1o, 12 is an optical lens, 13 is XL-COD, 14 is a drive unit that operates IL-10D13, 16 is IL-1
This is a signal processing unit that converts the signal output from the 0D13 into a television signal.

The operation of the conventional high-speed video camera using IL-COD configured as described above will be described below.

First, a shutter speed is selected using the 11 shutter control units, and the 10 mechanical shutters are opened and closed at the selected shutter speed. Then, while the mechanical shutter 1o is open, the optical signal that enters through the optical lens 12 is accumulated, detected and converted into an electrical signal by the IL-COD 13, and converted into a television signal by the signal processing unit 16. .

The configuration and operation of IL-(jcD will be explained below using FIGS. 4 to 6. In FIG. 4, 16 is a photodiode 17 as a photoelectric conversion element, and this vertical transfer register is a vertical transfer register. Transfer gate 18°, 19
, 20.21. 22 is a signal readout gate.Equivalently, vertical transfer gates 18 and 2o
It is common to 23 is a vertical transfer pulse supply terminal.

24 is a horizontal transfer register, and this horizontal transfer register is composed of horizontal transfer gates 25 and 26. 27
is a horizontal transfer pulse supply terminal.

Reference numeral 28 denotes a charge detection section, which converts the transferred signal charge into a signal voltage. The charge detection section 28 is usually a floating diffusion amplifier (Floating Di
fffusion Amplifier). 29 is a signal output terminal. 30 is an overflow drain control gate, 31 is an overflow drain, and 32 is an overflow drain control gate voltage supply terminal.

The operation of the IL-COD configured as above will be explained next.

The photodiode 16 photoelectrically converts incident light from a subject to obtain signal charges. Among the charges obtained by photoelectric conversion, excess charges are sucked out to the overflow drain 31 via the overflow drain control gate 3o. The amount of charge sucked out to the overflow drain 31 is determined by the DC voltage applied from the overflow drain 32 control gate voltage supply terminal. The signal charge obtained by photoelectric conversion is sent to the signal readout gate 22.
is read into the vertical transfer gate constituting the vertical transfer register 17 via the vertical transfer pulse supply terminal 23, and sequentially transferred in the vertical direction, that is, in the direction of the horizontal register 24, by the vertical transfer pulse supplied from the vertical transfer pulse supply terminal 23, and one horizontal The data is read into the horizontal transfer register 24 line by line. The signal charge read into the horizontal transfer register is sequentially transferred to the charge detection section 28 from the horizontal transfer pulse supplied from the horizontal transfer pulse supply terminal 27, converted into a voltage by the charge detection section 28, and then output from the signal output terminal 29. Obtained as a point sequential signal. A television signal is obtained by passing the dot sequential signal obtained by the method described above through the signal processing section 16 shown in FIG.

FIG. 5 shows a timing chart of the vertical transfer pulse supplied to the vertical transfer pulse supply terminal of the IL-COD and the voltage supplied to the overflow drain control gate voltage supply terminal, and the explanation will be given below.

33 and 34 are charge read pulses for reading signal charges from the photoelectric conversion element to the vertical transfer register, and 36 are vertical transfer pulses for sequentially transferring the signal charges read to the vertical transfer register toward the horizontal register. The signal charge accumulated in the photoelectric conversion element between the charge readout pulse 33 of the first field and the charge readout pulse 34 of the second field is transferred to the second field /l/)' based on the operation of the IL-COD. The signal charge accumulated in the photoelectric conversion element between the charge read pulse 34 of the second field and the charge read pulse 330 of the first field is converted to the television signal of the first field based on the operation of the IL-COD. The signal goes off. The excess charge at this time is determined by the overflow drain control gate voltage, the voltage value Va of the 36 DC voltages supplied to the 'supply terminal.

Problems to be Solved by the Invention However, the above-mentioned high-speed video camera using the IL-COD uses a mechanical shutter, which is structurally stiff, increases weight, and requires mechanical precision. Therefore, it has the disadvantage that the cost also increases significantly.

In view of the above problems, the present invention does not use a mechanical shutter,
By superimposing a new signal on the IL-COD drive signal, a high-speed video camera that can obtain performance equivalent to a high-speed video camera using a mechanical shutter is provided.Means for solving the problem In order to solve the above-mentioned problems, the present invention sets the potential of the automatic flow drain control gate at any time between the readout pulse 1 and the next readout pulse 2 for reading out the charge from the photoelectric conversion element to the vertical transfer register. A solid-state image sensor drive circuit that generates a charge accumulation time control signal to control so that not only excess charge but also all charges (not accumulated in the photoelectric conversion element) are sucked out to the -flow drain. It is equipped with a configuration having the following.

Operation The present invention has the above-described configuration; - the accumulation time of charges read out from the solid-state image sensor during the vertical scanning period is controlled;
This provides the same effect as the method of controlling the amount of incident light using a mechanical shutter.

Examples Below, regarding high-speed video cameras according to examples of the present invention,
This will be explained with reference to the drawings.

FIG. 1 shows a block diagram of the overall configuration of a first embodiment of the present invention. In Figure 1, 1 is an optical lens, 2
is IL-1cI), 3 is the drive unit that operates 2, and 4 is 2
This is a signal processing unit that converts the signal output from the TV into a television signal.

The operation of the high-speed video camera using the IL-COD configured as described above will be explained below with reference to FIGS. 1 and 2.

First, FIG. 2 is a timing chart of the vertical transfer pulse supplied to the vertical pulse supply terminal of the IL-COD and the charge accumulation time control signal supplied from the autocouple 70-drain control gate voltage supply terminal, 6.6 is the same as 33.34 in FIG. 6 of the conventional example, and is a charge read pulse for reading signal charges from the photoelectric conversion element to the vertical transfer register; 7 is the same as 35 in FIG. 5, and is a charge read pulse to the vertical transfer register. This is a vertical transfer pulse that sequentially transfers read signal charges in the direction of the horizontal transfer register. Reference numeral 8 denotes a charge accumulation time control signal for sucking out the charges accumulated in the photoelectric conversion element to the -flow drain.

The charge accumulation time control signal 8 is increased by time t& from the charge read pulse 6 of the first field to the potential vb. In this case, vb is a potential that allows all of the charges accumulated in the photoelectric conversion element to be sucked out to the overflow drain. Therefore, all the light incident on the photoelectric conversion element during this time ta is sucked out by the overflow drain and does not become a video signal. then the second
The charge accumulation time control signal 8 is lowered to the potential Va until the field charge readout pulse 6, that is, by tb. Va is the same potential as V& in FIG. 6 of the conventional example, and is a potential that allows only excess charge to be sucked out to the overflow drain. Therefore, the light incident on the photoelectric conversion element during time tb is converted into charges, read out to the vertical transfer register by the charge read pulse 6, transferred toward the horizontal transfer register by the vertical transfer pulse 7, and then transferred to the horizontal transfer register by the vertical transfer pulse 7. It becomes a two-field television signal, and similarly, the charges accumulated after time ta has elapsed since the second field's charge read pulse 6 are read out to the vertical transfer register by the first field's charge read pulse 6, and then by the vertical transfer pulse 7. The first data is transferred to the horizontal transfer register.
It becomes the field television signal.

As described above, according to this embodiment, the potential of the overflow drain control gate that controls the amount of charge that is sucked out of the photoelectric conversion element to the overflow drain in the drive circuit of the IL-CCI is set perpendicularly to the photoelectric conversion element. Charge accumulation time control that controls not only excess charge but all charges to be sucked out to the overflow drain only during an arbitrary time between charge readout signal 1 for reading charge to the transfer register and next charge readout pulse 2. By providing a signal, the signal time accumulated in the photoelectric conversion element can be electrically controlled and used as a high-speed video camera.

In the first embodiment, 2 in FIG. 1 is an IL-4CD.
However, 2 in FIG. 1 may be a frame transfer charge-coupled solid-state imaging device. Further, the ratio between ta and tb in FIG. 2 is not particularly determined.

Effects of the Invention As described above, according to the present invention, it is possible to obtain an excellent effect of electrically controlling the accumulation time of charges read out from a photoelectric conversion element of a solid-state image sensor within a vertical scanning period.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the overall configuration of the first embodiment of the present invention, Fig. 2 is a timing chart of part of the signals generated from the drive section of Fig. 1, and Fig. 3 is a conventional L-COD. 4 is a block diagram of the overall configuration of a high-speed video camera using be. 1...Optical lens, 2...IL-CO
D, 3... Drive unit, 4... Signal processing unit. Name of agent: Patent attorney Satoshi Nakao and one other person Figure 1

Claims (1)

[Claims] An overflow drain is provided to suck out excess charge accumulated in the photoelectric conversion element of the solid-state image sensor, and the potential of the overflow drain control gate that controls the amount of charge sucked out to the overflow drain is transferred from the photoelectric conversion element to the vertical transfer register. Control is performed so that not only excess charge but all charges are sucked out to the overflow drain only during an arbitrary time period between the first charge read pulse for reading charges to the overflow drain and the second charge read pulse. 1. A video camera device comprising: a solid-state image sensor driving circuit that generates a charge accumulation time control signal; and electrically controls an accumulation time of charges accumulated in the photoelectric conversion element.