JPS58117777A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To prevent the deterioration in picture quality due to smear and blooming phenomena, by sweeping out unnecessary electric charges remained in a vertical transfer section, just before signal charges obtained at photodetectors of a solid-state image sensor are transferred to the vertical transfer section. CONSTITUTION:A still picture provided at the outside of a camera body 1 is picked up at a solid-state image sensor 9 and recorded on a rotating magnetic disc 12. With the operation of a shutter mechanism 4, the image sensor 9 is exposed for a prescribed time from the timing of a vertical synchronizing signal and then shut. The signal charges are read out from the photodetectors of the image sensor 9 to the vertical transfer section after the prescribed exposure time, the unnecessary electric charges remained in the vertical transfer section are all swept out just before the readout and the pure signal charges without noise are outputted as the picture signals through the vertical transfer section.

Description

[Detailed Description of the Invention] The present invention provides a charge coupled device (CC1): Charge
The present invention relates to a solid-state imaging device using a solid-state image sensor formed by a Coup-Ied Device, etc., and particularly relates to a solid-state imaging device optimal for capturing still images.

Conventionally, solid-state imaging devices using solid-state image sensors formed with charge transfer elements such as CCDs constantly irradiate each light-receiving part of the image sensor with imaging light, and the light is emitted every 1 field period or 1 frame period. Various configurations have been proposed for use as a so-called video camera that performs continuous imaging operations by reading out imaging output signals. By the way, in solid-state image sensors, due to the structure in which signal charges obtained at the light receiving section are transferred, unnecessary charges leak into the transfer section or are thermally excited, which tends to cause the so-called smear phenomenon or blooming phenomenon. Conventionally, various measures have been taken on solid-state image sensors, such as forming an overflow drain along the transfer section or adopting a frame transfer type structure. Therefore, conventional solid-state image sensors have to have extremely complicated structures to prevent smear and blooming as described above, require advanced semiconductor manufacturing technology, are not easy to manufacture, and are extremely expensive. Met.

Conventionally, even when capturing a methyl image, a solid-state imaging device using an extremely expensive solid-state image sensor as described above has been used.

The present invention provides a solid-state imaging device that captures an image with a solid-state image sensor by controlling the exposure time using an optical shutter that opens and closes an optical path of imaging light. Immediately before transferring the signal charge obtained in the vertical transfer section to read the signal, the unnecessary charge remaining in the vertical transfer section is swept out and discarded, and the signal charge is transferred through the vertical transfer section with the shutter closed. The present invention is characterized in that the signal charge is read out by the image sensor, thereby simplifying the structure of the solid-state image sensor and preventing deterioration of image quality due to smearing and blooming phenomena. This provides an optimal solid-state imaging device.

Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment.

In the embodiment shown in FIG. 1, a still image is captured by a solid-state image sensor 9, and the image information is transferred to a rotating magnetic disk 12.
The present invention is applied to an electronic still camera that records images. In this embodiment, a lens system 2, an iris mechanism 3, a shutter mechanism 4, a mirror 6, a viewfinder 8, a shutter operating member 5, etc. are arranged inside the camera housing 1, as in a normal optical film type camera. has been done. In place of the optical film, it includes a solid-state image sensor 9 and a magnetic recording section 20 that convert image information of a subject image into electrical signals and record them.

The magnetic recording unit 20 uses a rotating magnetic disk 2 as a magnetic recording medium, and a jacket 14 containing the rotating magnetic disk 2 is detachably attached to the camera housing 1. A drive motor 13 rotates the rotating magnetic jacket 12 at a constant speed, and a magnetic head 11 magnetically records image information.

Image information converted into electrical signals by the solid-state image sensor 9 is supplied to the magnetic head 11 via a signal recording circuit 10.

Here, the drive circuit 40 of the shutter mechanism 4, the drive circuit 50 of the solid-state image sensor 9, and the drive circuit 60 of the drive motor 13 are interlocked with each other by the control circuit 10 that is brought into operation by the operation of the shutter operation member 5. As will be described later, when the shutter operation member 5 is operated during an imaging operation, the recording unit 20 can perform a recording operation in synchronization with the imaging operation by the solid-state image sensor 9. An effective shutter operation is performed after the rotational phase and rotational speed of the rotating magnetic disk 12 are stabilized. Incidentally, on the rotating magnetic disk 11 of the recording section 20, image information of one still image is concentrically recorded for each recording track. By reproducing the image information magnetically recorded on the magnetic disk 11 with a reproducing device (not shown), a still image can be monitored on the screen of an ordinary television receiver. The mechanism 4 is normally in an open state. A drive circuit 4 for the shutter mechanism 4
0 is the shutter operation signal Ss when the shutter operation member 5 is operated and the shutter operation signal Ss is supplied from the control circuit 70 at a timing is, for example.
In response to this, the shutter mechanism 4 is brought into a closed state after a predetermined exposure time Ts based on the timing to of the vertical synchronization signal Vsyne has elapsed. Furthermore, the shutter mechanism 4
The solid-state image sensor 9, which is irradiated with imaging light through an optical path provided with the imaging light, performs imaging operation in synchronization with the vertical synchronization signal VPync, and immediately before reading out the signal charge obtained by the irradiation of the imaging light as a video signal. Next, unnecessary charges remaining in the signal transfer section are swept out and discarded, and the video signal is read out with the shank mechanism 4 closed, that is, in a light-shielded state. The operations of the shutter mechanism 4 and the solid-state image sensor 9 are shown in the time chart of FIG.

Here, as the solid-state image sensor 9 in this embodiment, an interline transfer type COD image sensor having a structure as shown in FIG. 3, for example, is used. In FIG. Each light receiving section is arranged in a matrix in a corresponding manner, and
Reference numeral 92 indicates each light receiving section arranged in a matrix in correspondence with each picture element of the second field, and 93 indicates each of the above-mentioned light receiving sections 91.
92 are vertical transfer register sections provided along the vertical columns; 94 is a horizontal transfer register section provided at one end side of the vertical transfer register section 93; 95 is a horizontal transfer register section provided along the vertical transfer register section 93; This is a charge absorption section provided on the end side, and 96 and 97 are transfer gate sections provided between each of the light receiving sections 91 and 92 and the vertical transfer register section 93. By the way, above! The self-vertical transfer register section 93 is capable of bidirectional transfer, with a function of transferring signals in the direction of the horizontal transfer register section 94 on one end side and a function of transferring signals in the direction of the charge absorption section 95 on the other end side. It has a structure.

In the solid-state image sensor 9 having the above-described structure, each transfer gate 96.97 is opened during the gate opening period Tw synchronized with the vertical synchronization signal Vsync, and the images accumulated in each light receiving section 91.92 during the charge accumulation period Tc are captured. Signal charges corresponding to the amount of light are transferred to the vertical transfer register section 93 through the respective transfer ports 96 and 97. During the signal readout period TR, the signal charge transferred to the vertical transfer register section 93 is transferred to the horizontal transfer register section 94 by a vertical transfer port/Ov synchronized with the horizontal synchronization signal Hsync, at a rate of 1 for every horizontal scanning period IH. The data is vertically transferred horizontally line by line and sequentially read out via the horizontal transfer register section 94.

Furthermore, the signal readout period To and the gate open period Tw
A charge sweep period TL is provided between the charge sweep period Tt, and during the charge sweep period Tt, the vertical transfer register section 93 is transferred at high speed and driven by a longitudinal terminal. The remaining unnecessary charge is transferred to the charge absorption section 95.
be thrown away.

Further, the signal reading operation from the solid-state image sensor 9 is performed in conjunction with the operation of the shutter mechanism 4.

That is, as shown in the time chart of FIG. 2, the shank operation signal Ss (see FIG. 2 C) is output at timing is, and the subsequent first vertical synchronization signal Vsync (see FIG. 2 C) is output. ), the shank mechanism 4 enters the closed state (see FIG. 2C) after the exposure period Ts has elapsed based on the timing to, the readout operation of the solid-state image sensor 9 starts from the timing to. It can be switched as follows.

First, during the period TA before the timing to, all transfer gates 96,97 during each gate opening period are
is opened, and the signal charges of the first field and the second field obtained in each of the light receiving sections 91 and 92 during the charge accumulation period Tc are simultaneously transferred to the vertical transfer register section 93 as shown in FIG. 4A.

Then, the signal charges of each field are added and combined and read out through the horizontal transfer register section 94 as shown in FIG. 4B during the signal readout period TR.

When the reading of the signal charges is completed, the charge sweep period T s
, and as shown in FIG. 4C, immediately after the unnecessary charge remaining in the vertical transfer register section 93 is absorbed, the gate opening period Tw begins and the transfer gates 96 and 97 are opened again. He, each light receiving section 9
The signal charges S from 1 and 9i3 are vertically transferred and transferred to the disk section 93. The gate above is open! 1M-TW, each operation in the signal readout period TR1 and the charge sweep period TL is synchronized with the vertical synchronization signal Vsy.
It is performed by manipulating the word nc.

Next, in the period To after the timing to, if the exposure period Ts until the shutter mechanism 4 is closed spans a plurality of fields (two fields in this example), the exposure period '1' During S, each transfer gate 96.97 is prohibited from opening, and each light receiving section 91.92 is prohibited from opening.
is in a charge accumulation state throughout each field period including the exposure period '1'S. And the above timing 10
The shutter mechanism 4 is closed after a predetermined exposure period Ts has elapsed, and the period during which the shutter mechanism 4 is in an open state '
1"CL, each light receiving section 91.9 during the exposure period Ts.
The signal charges accumulated in 2 are read out field by field.

That is, during the first vertical scanning period VA during the shutter closing period Tcf-, as shown in the fourth diagram, the transistors and sphere gates 96 of each light receiving section 91 for the first field are opened during the gate opening period TWA. Then, the signal charge of the first field is transferred to the vertical transfer register section 93 and read out during the signal readout period TRA. Next vertical scanning period V
During B, as shown in FIG. 4E, the transfer gate 97 of each light receiving section 92 for the second field is opened during the gate opening period TwB and transferred to the vertical transfer register section 93, and the signal is read out during the signal readout period TwB. Read during TRB. In addition,
Immediately before each of the above gate opening periods TWA and TWB,
Charge sweep periods TLA and TLB are provided, respectively, and unnecessary charges are discarded into the charge absorption section 95.

In this way, each light receiving section 91.9 during the exposure period Ts.
The signal charge accumulated in the second field indicates each image information of the first field and the second field without any time lag, so there is no flicker even when the subject is moving. This results in a video signal of a frame still image without any phenomena or the like. Furthermore, since the signal charge is read out with the shutter mechanism 4 closed, it is not accompanied by a smear phenomenon. Furthermore, since the unnecessary charges remaining in the vertical transfer register section 93 are swept out immediately before the signal charges are transferred to the vertical transfer register section 93, the blooming phenomenon due to the unnecessary charges is not caused. Furthermore, in the embodiment described above, since the normally open shack mechanism 4 is used, the signal 'charge' read from the solid-state image sensor 9 is used before operating the shack operating member 5 to capture a still image. It is possible to automatically set the shutter speed and aperture, or automatically adjust the level of the video signal.

FIG. 5 shows an embodiment of a so-called aperture priority automatic control system.

In FIG. 5, the solid-state image sensor 9 is driven by each transfer lock pulse lu, 51v generated by the drive circuit 50 based on the vertical synchronization signal Vsync and horizontal synchronization signal FI8yTIC from the synchronization signal generator 51. , to perform the above-described imaging operation. The video signal read from the solid-state image sensor 9 is supplied to the recording system circuit 10 described above and also to the average value detection circuit 41.

This average value detection circuit 4.1 supplies the average DC level LA of the video signal from the solid-state image sensor 9 to the level comparator 43 as a detection output. Here, the detection output of the detection circuit 41 is such that the DC level decreases when the image of the subject captured by the solid-state image sensor 9 is bright, and conversely, the DC level increases when the image of the subject is dark. .

Further, a vertical synchronization signal V m is output from the synchronization signal generator 51.
The sawtooth wave signal generator 42 to which Lync is supplied forms a sawtooth wave signal SW as shown in FIG. 43.

Here, the inclination angle θ of the sawtooth wave signal SW is set according to the setting state of the aperture mechanism 3, and is set to a small angle so that the optical path of the imaging light is narrowed down by the aperture mechanism 3. .

In the level comparator 43, the sawtooth wave signal SW
A rectangular wave signal SQ as shown in FIG.
The monostable multivibrator 44 is triggered at its falling edge. From the monostable multi-by-break 44, a shuck pulse SP as shown in the sixth diagram is obtained every 1v of vertical scanning period. The shutter pulse SP is outputted via an AND gate 45.

The AND gate circuit 45 is connected to the Nyanota operation member 5.
A gate signal formed by the first flip-flop 46 and the second flip-flop 47 is supplied. The first flip-flop 46 is triggered every time the release switch 71 is closed by operating the shutter operating member 5, and sends the positive output signal to the J input of the second flip-flop 47 to logic "1". do. The second flip-flop block 47
uses the vertical synchronization signal V sy as its clock input.
P and G pulses synchronized with ne are supplied, and the J input becomes logic "1" and is triggered by the first PG pulse. Here, the PG pulse is synchronized with the vertical synchronization signal Vayoa in the servo system of the drive motor 13 of the rotating magnetic disk 12, and is obtained at the same timing as the vertical synchronization signal Vsyne. 2nd above
The positive output signal of the flip-flop 47 is supplied to the first flip-flop 46 as a clear signal, and is also supplied to the AND gate 45 as a gate signal. Here, the first flip-flop 46 is
As shown in FIG. 6E, from the timing ts when the release switch 11 is closed to the timing to of the first PG pulse.
An affirmative output signal of logic "1" is output until the end. Further, as shown in FIG. 5F, the second flip-flop 47 outputs an affirmative output signal of logic r11 from the timing to to the timing t1 of the next PC) pulse.

Therefore, from the AND gate 45, the exposure period T starts from the timing to of the first vertical synchronization signal Vsyne after the timing ts when the shutter operating member 5 is operated.
After s has elapsed, a shutter pulse as shown in the sixth step C is output. ANI) The shack mechanism 4 is brought into the closed state by the shutter pulse from the cage 45. Then, while the shutter mechanism 4 is closed, the video signal of the frame still image is read out from the solid-state image sensor 9 as described above.

As is clear from the description of the above embodiment, the smear phenomenon can be prevented by reading signal charges from the solid-state image sensor with the shank that opens and closes the optical path of the imaging light irradiated onto the solid-state image sensor closed. It is possible to capture a still image with high image quality without any distortion. In addition, when reading signal charges from a solid-state image sensor, just before transferring the signal charges obtained at each light receiving section to the vertical transfer section, there is a problem in that unnecessary charges remaining in the vertical transfer section are swept out and discarded. , can prevent the flumink phenomenon. Therefore, in a solid-state imaging device 1 that captures an image with a solid-state image sensor by controlling the exposure time using an optical shack that opens and closes an optical path for imaging light,
Immediately before transferring the signal charges obtained in each light receiving section of the solid-state image sensor to the vertical transfer section by opening the shutter and performing signal readout, the unnecessary charges remaining in the vertical transfer section are swept out and discarded, According to the present invention, the gist is that signal charges are read out via the vertical transfer section with the shutter closed.
Since the smear phenomenon can be prevented by effectively using an optical shutter, the structure of the solid-state image sensor can be simplified, and still images can be taken with good image quality, allowing the desired purpose to be fully achieved. It can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention. FIG. 2 is a time chart for explaining the operation of the above embodiment. FIG. 3 is a schematic plan view showing an example of the structure of the solid-state image sensor used in the above embodiment. Figures 4 to 4E are schematic plan views for explaining the signal readout operation from the solid-state image sensor, and Figure 4 shows the state of movement of signal charges during a normal gate opening period. , FIG. 4B shows the movement state of the signal charge during the signal readout period, the fourth screen C shows the movement state of the signal charge during the charge sweep period, and the fourth figure shows the movement state of the signal charge during the signal readout period. Fig. 4E similarly shows the movement state of signal charges for the second field. FIG. 5 is a block diagram showing a circuit structure when an aperture-priority automatic control system is configured in the above embodiment. FIG. 6 is a time chart for explaining the operation of the automatic control system. 4......Shutter mechanism 5...
......Shutter operation member 9...
. . . Solid-state image sensor 10 . . . Recording circuit 11 . . . Magnetic head 12 . . . Rotating magnetic disk 13
... Drive motor 40 ... Shutter drive circuit 50 ...
...Image sensor drive circuit 60...
...Motor drive circuit 10...Control circuit 91.92...Light receiving section 93...Vertical transfer register section 94...
...Horizontal transfer register section 95...
・Charge Absorption Unit Patent Applicant: Sony Corporation Agent, Patent Attorney: Kodo Koike, Sakae Himura - Procedural Amendment Written Form) May 11, 1980 Commissioner of the Japan Patent Office Shima 1) Haruki Tono1, Display of the Case Showa 1956 Patent application No. 212056 2 Invention 0 Title □ Gymnastics image device 3, relationship with the person making the amendment case Patent applicant address 6-7-35, Kitashinyo, Tokyo Parts Store @, (2
18) Sony Corporation name) Representative: Kazuo Iwama 4, Agent: 105 April 9, 1980 (Delivery date: April 27, 1980)
6. Drawings subject to correction

Claims (1)

[Claims] In a solid-state imaging device that captures an image with a solid-state image sensor by controlling the exposure time using an optical shutter that opens and closes an optical path for imaging light, opening the shutter allows the light to be transmitted to each light-receiving part of the solid-state image sensor. Immediately before transferring the signal charge to the vertical transfer section and reading the signal, the unnecessary charge remaining in the vertical transfer section is swept out and discarded, and the signal is transferred through the vertical transfer section with the shutter closed. A solid-state imaging device characterized in that charge is read out.