JPS63114379A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To discharge an undesired electric charge to a substrate efficiently by providing a MOS switch whose source is connected to the final stage of a vertical transfer register and controlling the gate potential of the MOS switch. CONSTITUTION:A signal charge stored from the 1st charge pulse to the 2nd charge pulse in a photodiode 201 is outputted as a TV signal and the undesired charge stored during a period from the 2nd charge pulse to the 1st charge pulse is transferred at a high speed sequentially during the period of vertical high speed transfer. When a gate pulse HG pulse is inputted to a BC pulse input section 207, since the undesired charge discharging MOS switch 205 whose source is connected to the electric charge transmission/reception part from the vertical transfer register 202 to the horizontal transfer register 203 is conductive, then the undesired charge is discharged to the substrate 206 efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a solid-state imaging device that can be used in video cameras and the like.

2. Description of the Related Art In recent years, video tape recorders have adopted functions such as still playback, frame-by-frame forwarding, and slow playback.

However, the NTSC video signal for one field in a video tape recorder is 1/1/2 in a film camera.
The signal has a period corresponding to a shutter speed of /80 seconds or 1/3Q seconds, so for fast moving subjects,
When a video tape recorder is placed in a stationary state, image blur occurs.

In a video camera using a solid-state imaging device, it is possible to electrically control the photoelectric conversion time, which corresponds to the shutter speed of a film camera, and make it faster than 1/60 second. (Hereinafter, electrically controlling the photoelectric conversion time of a solid-state camera loading device will be referred to as an electronic shutter.

) A method of driving a solid-state imaging device for realizing the above-mentioned electronic shutter will be described below with reference to the drawings. (
Reference Patent Application No. 60-236062) The basic structure of the solid-state imaging device is composed of a photoelectric conversion section 41, a vertical transfer section 42, a horizontal transfer section 43, and a signal charge detection section 44, as shown in FIG. The arrow indicates the direction of normal signal charge transfer. Fourth
In the figure, 45 is a discharge section provided at one end of the vertical transfer section 42 in the direction opposite to the horizontal transfer section 3 side.

FIG. 5 shows an example of typical drive pulses and outputs of a solid-state imaging device during electronic shutter operation. In Figure 5 (&)
is a composite blanking signal, (b) is a transfer pulse (hereinafter abbreviated as charge pulse) that transfers the signal charge of the photoelectric conversion section to the vertical transfer section, and (0) is a transfer pulse that transfers the signal charge of the vertical transfer section to the horizontal transfer section sequentially. The transfer pulse (hereinafter abbreviated as vertical transfer pulse) (d) is the transfer pulse (hereinafter abbreviated as horizontal transfer pulse) that transfers the signal charge in the horizontal transfer section to the signal charge detection section. (The number of pulses is reduced.) (e) is the signal output from the solid-state imaging device.

During the vertical retrace period, the first charge pulse 61 is used to transfer unnecessary signal charges that have been accumulated in the photoelectric conversion section in the period 54 and are not used as a video signal to the vertical transfer section 62 . Next, the vertical transfer section 52 is driven in the direction opposite to the arrow in FIG. Transfer to 46. The discharge section 45 discards all the transferred signal charges.

Thereafter, the charge pulse 52 of the tube 2 transfers the signal charge accumulated in the photoelectric conversion section 41 during the period 63 after the first charge pulse 51 to the vertical transfer section 52 . After this, during the vertical scanning period until the next charge pulse 51, the signal charge for one horizontal line is transferred from the vertical transfer section 42 to the horizontal transfer section 43 by the vertical transfer pulse every horizontal period, as in the case where the electronic shutter is not used. The signals are sequentially transferred, and signals are output in series from the horizontal transfer section 43 through the signal charge detection section 44 in response to horizontal transfer pulses.

As a result, the signal output from the solid-state imaging device during the vertical scanning period is only the signal charge photoelectrically converted during period 63 in FIG. It can be a period of 10 to 1 and 0. In other words, this time is 1/eo of a film camera.

Corresponds to a shutter speed of ~1/1200 seconds.

By using the above-mentioned electronic shutter, the sensitivity of the video camera will be reduced by the increase in shutter speed, but even if you freeze, frame advance, slow, etc. during playback on a video tape recorder, the image will not change as compared to the moving image. can be reduced.

Problems to be Solved by the Invention However, in the above configuration, the unnecessary charge read out by the first charge pulse 51 is discharged after being reversely transferred through the vertical transfer stage. Therefore, there is a possibility that problems such as residual discharge may occur.

Therefore, the present invention focuses on the above problem, and by providing a MOS switch whose source is connected to the final stage of the vertical transfer register, the unnecessary charge read out by the first charge pulse is transferred sequentially through the vertical transfer stage. After that, it becomes possible to efficiently discharge the water through the MOS switch.

Means for Solving the Problems In order to solve the above problems, the present invention provides a MOS switch whose source is connected to the final stage of the vertical transfer register of a solid-state image sensor, and controls the gate potential of the MOS switch. The present invention relates to a solid-state imaging device provided with means for discharging unnecessary charges read out by the first charge pulse to the substrate by the MOS switch.

Effect of the Invention The present invention achieves efficient discharge of unnecessary charges from a high-speed solid-state imaging device through the above-described configuration.

Embodiments Hereinafter, solid-state imaging devices according to embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an overall block diagram of an embodiment of the present invention. In FIG. 1, 1o1 is an optical lens, 102 is an interline type COD (charge coupled device), 103 is a signal processing section, 104 is a solid-state image sensor driving circuit for driving the interline type COD, 105 is a pulse generation circuit for signal processing.

The operation of the solid-state imaging device using the interline type can configured as described above will be described below with reference to FIGS. 1, 2, and 3.

First, the internal configuration of the solid-state image sensing device (interline type C0D) shown at 102 in FIG. 1 will be briefly explained using FIG. 2. 201 is a photodiode (charge storage unit), 202
203 is a vertical transfer section, 203 is a horizontal transfer section, 204 is a signal output section, 205 is a MOS switch for discharging unnecessary charges, 206
207 is the gate pulse (HG) of the MOS switch for discharging unnecessary charges.
This is the input section.

The optical signal passing through the optical lens shown at 101 in FIG. 1 is accumulated in the photodiode shown at 201 in FIG. 2 by operating the solid-state image sensor driving circuit shown at 102 in FIG. 1 in electronic shutter mode. , a of FIG. 3 305
The signal charge accumulated during the period shown by +b -1-c (the period from the first charge pulse shown at 302B in FIG. 3 to the second charge pulse shown at 302b) is
In the period shown in d in FIG. 305 (period from the second charge pulse shown in 302b in FIG. 3 to the first charge pulse shown in 302a), the TV multiplied signal is output, and the third
The unnecessary charge accumulated during the period shown in 305d in the figure is 3
During the vertical high-speed transfer period shown in b of 05, high-speed transfer is performed in the forward direction, and by inputting the HG pulse to the 1 (G pulse input section) shown in 207 of FIG. The unnecessary charge is removed by an unnecessary charge discharging MO shown in 205 whose source is connected to a charge transfer part from a vertical transfer register shown in 202 to a horizontal transfer register shown in 203.
Since the S switch becomes conductive, the water is efficiently discharged to the substrate shown at 206.

By the above operation, only the necessary signal charges are outputted from the output section shown at 204, and unnecessary charges are efficiently discharged to the substrate shown at 206. Next, the signal is processed by the signal processing section 103 shown in FIG. 1 to obtain a high-speed TV signal.

Effects of the Invention As described above, according to the present invention, it is possible to obtain the excellent effect of efficiently discharging unnecessary charges from a high-speed solid-state imaging device.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram of an embodiment of the present invention, FIG. 2 is an internal block diagram of a solid-state image sensor according to an embodiment of the present invention, and FIG.
The figure is a typing diagram of an embodiment of the present invention, FIG. 4 is an internal block diagram of a conventional solid-state image pickup device, and FIG. 6 is a typing diagram for explaining the means for operating an electronic shutter in a conventional solid-state image pickup device. be. 101... Optical lens, 102... Solid-state image sensor, 103... Signal processing section, 104...
...Solid-state image sensor drive circuit, 105...
Pulse generation circuit, 201...Photoelectric conversion element, 2
02... Vertical transfer section, 203... Horizontal transfer section, 204... Output section, 205...
・MOS switch for discharging unnecessary charges, 206...
Solid-state image sensor substrate (unnecessary charge discharge section). Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4

Claims (1)

[Claims] A first charge pulse for reading charges accumulated in a photodiode of a solid-state image sensor during one vertical scanning period to a vertical transfer register of the solid-state image sensor; A second charge pulse is used to read out the charges accumulated in the solid-state image sensor into the vertical transfer register of the solid-state image sensor, and the signal charge accumulation time to be extracted as a television signal from the photodiode of the solid-state image sensor is electrically determined. In the solid-state imaging device to be controlled, a MOS switch is provided whose source is connected to the charge transfer section from the vertical transfer register to the horizontal transfer register, and the unnecessary charge read out by the first read pulse is transferred to the gate pulse of the MOS switch. A solid-state imaging device characterized by comprising means for controlling and discharging to a substrate of the solid-state imaging device.