JPH0320109B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a still image recording device that obtains an imaging output signal of a still image using a solid-state image sensor and records it on a rotating magnetic disk.

Conventionally, solid-state imaging devices using solid-state image sensors formed from imaging elements such as CCDs constantly irradiate each light-receiving part of the image sensor with imaging light, and change the imaging output amplitude every one field period or one frame period. Various configurations have been proposed for use as a so-called video camera that performs continuous reading imaging operations by reading out.

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 and 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. It was hot.

Conventionally, even when capturing a still image using a solid-state image sensor, an extremely expensive solid-state image sensor with measures against smear and blooming as described above has been used.

Therefore, the present invention simplifies the structure of a solid-state image sensor by providing an optical shutter, and also performs a still imaging operation linked to the shutter with this solid-state image sensor, thereby reducing the image quality due to the smear phenomenon. An object of the present invention is to provide a still image recording device that can obtain an imaging output signal of a still image and reliably record it on a rotating magnetic disk without deterioration.

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

The embodiment shown in FIG.
The present invention is applied to an electronic still camera that captures still images and records the image information on a rotating magnetic disk 12. 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 camera. has been done. In place of the optical film, it is equipped with 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 section 20 uses a rotating magnetic disk 12 as a magnetic recording medium, and a jacket 14 containing the rotating magnetic disk 12 is detachably attached to the camera housing 1.
The rotary magnetic disk 12 is rotated at a constant speed by a drive motor 13 provided therein, and image information is magnetically recorded by a magnetic head 11. Image information converted into electrical signals by the solid-state image sensor 9 is transferred to the magnetic head 11 by the signal recording circuit 1.
0.

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 controlled to operate in conjunction with each other by a control circuit 70 that is brought into operation by 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 rotational phase and rotational speed of the rotating magnetic disk 12 are changed so that the recording unit 20 can perform a recording operation in synchronization with the imaging operation by the solid-state image sensor 9. Effective shutter operation begins after stabilization. Incidentally, on the rotating magnetic disk 12 of the recording section 20, image information of one still image is concentrically recorded for each recording track. The rotating magnetic disk 12
By reproducing image information magnetically recorded on a reproducing device (not shown), a still image can be monitored on the screen of an ordinary television receiver.

The shutter mechanism 4 in this embodiment is normally in an open state. The drive circuit 40 of the shutter mechanism 4 receives, for example, t _S from the control circuit 70 when the shutter operating member 5 is operated.
When the shutter operation signal S _S is supplied at _a timing such that the _shutter operation signal _{S S} is supplied, the shutter mechanism 4 to the closed state. Further, the solid-state image sensor 9, which is irradiated with imaging light through an optical path provided with the shutter mechanism 4, performs an imaging operation in synchronization with the vertical synchronization signal V _syoc , and a signal obtained by the irradiation of the imaging light. Immediately before reading out the charge as a video signal, any unnecessary charge remaining in the signal transfer section is swept out and discarded, and the video signal is read out with the shutter 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, for example, an interline transfer type CCD image sensor having a structure as shown in FIG. 3 is used. In FIG. 3, reference numeral 91 indicates each light receiving section arranged in a matrix pattern corresponding to each picture element of the first field, and 92 indicates a light receiving section arranged in a matrix pattern corresponding to each picture element of the second field. 93 is each of the above-mentioned light receiving parts 91, 92.
94 is a horizontal transfer register section provided at one end side of the vertical transfer register section 93;
95 is a charge absorption section provided at the other end of the vertical transfer register section 93;
are transfer gate sections provided between the light receiving sections 91 and 92 and the vertical transfer register section 93. Note that the vertical transfer register section 93 is as follows:
It has a structure 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.

In the solid-state image sensor 9 having the above structure, the transfer gates 96 and 97 are opened during the gate opening period T _W synchronized with the vertical synchronization signal V _syoc , and the charge is accumulated in the light receiving sections 91 and 92 during the charge accumulation period T _C. Signal charges corresponding to the amount of imaging light are transferred to the vertical transfer register section 93 through the transfer gates 96 and 97. The signal charges transferred to the vertical transfer register section 93 are transferred during the signal readout period _TR .
One horizontal line is vertically transferred to the horizontal transfer register section 94 every horizontal scanning period 1H by the vertical transfer clock _φV synchronized with the horizontal synchronization signal _Hsyoc .
The data are sequentially read out via the horizontal transfer register section 94. Further, a charge sweep period T _L is provided between the signal readout period T _R and the gate open period T _W , and during the charge sweep period T _L , the vertical transfer register section 93 is clocked by the high speed transfer clock φ _VS. By driving the vertical transfer register section 93, unnecessary charges remaining in the vertical transfer register section 93 are discarded into the charge absorption section 95.

Furthermore, 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 shutter operation signal S _S (see FIG. 2 B) is output at the timing t _S , and the subsequent first horizontal synchronization signal V _syoc (second If the shutter mechanism 40 enters the closed state (see FIG. 2C) after the exposure period T _S based on the timing _{t 0 of} FIG. The read operation is switched as follows.

First, in the period T _A before the above timing t ₀ ,
All the transfer gates 96 and 97 are opened during each gate opening period _TW , and the signal charges of the first field and the second field obtained in each light receiving section 91 and 92 during the charge accumulation period _TC are transferred to the fourth field. As shown in FIG. A, the data are simultaneously transferred to the vertical transfer register section 93.
Then, the signal charges of each field are added and combined and read out through the horizontal transfer register section 94 during the signal readout period _TR as shown in FIG. 4B. When the reading of the signal charges is completed, a charge sweep period T _L begins, and as shown in FIG. 4C, unnecessary charges remaining in the vertical transfer register section 93 are transferred to the charge absorption section 95 and discarded. Immediately after the unnecessary charges in the vertical register section 93 are swept out during the charge sweep period T _L , the transfer gates 96 and 97 are opened again during the gate opening period T _W.
Signal charges are transferred from each light receiving section 91 and 92 to a vertical transfer register section 93. The above gate opening period T _W ,
Each operation of the signal readout period T _R and the charge sweep period T _L is performed in synchronization with the vertical synchronization signal V _syoc .

Next, in the period T _B after the timing t ₀ , if the exposure period T _S until the shutter mechanism 4 is closed spans multiple fields (in this example, 2
The transfer gates 96 and 97 are prohibited from opening during the exposure period T _S , and the light receiving sections 91 and 92 remain in a charge accumulation state for each field period including the exposure period T _S. becomes. Then, the shutter mechanism 4 is closed after a predetermined exposure period T _S has elapsed from the above-mentioned timing t ₀ O, and a period T _CL in which the shutter mechanism 4 is in the closed state
During the exposure period T _S , each light receiving section 91, 92
The signal charges stored in the signal charge field are read out separately. That is, during the first vertical scanning period _VA during the shutter closing period _TCL , the transfer gate 96 of each light receiving section 91 for the first field is activated during the gate opening period _TWA , as shown in FIG. 4D. is opened, and the signal charges in the first field are transferred to the vertical transfer register section 93 and read out during the signal readout period _TRA . During the next vertical scanning period _VB , as shown in FIG. 4E, each light receiving section 9 for the second field
2 transfer gate 97 is the gate open period
It is opened during _TWB , transferred to the vertical transfer register section 93, and read out during the signal readout period _TRB . Note that charge sweep periods T _LA and T _LB are provided immediately before each of the gate opening periods T _WA and T _WB , respectively, and unnecessary charges are discarded in the charge absorption section 95.

In this way, each light receiving section 9 during the exposure period T _S
The signal charges accumulated at 0 and 92 indicate each image information of the first field and the second field without any time lag, so even if the subject is moving, Also, the video signal is a frame still image without any flickering phenomenon. Furthermore, since the signal charges are read out with the shutter mechanism 4 closed, there is no smear phenomenon. Furthermore, immediately before transferring the signal charge to the vertical transfer register section 93,
Since the unnecessary charges remaining in the vertical transfer register section 93 are swept out, the blooming phenomenon due to the above-mentioned unnecessary charges does not occur.

Furthermore, in the embodiment described above, since the normally open shutter mechanism 4 is used, the signal charge read out from the solid-state image sensor 9 is used before operating the shutter 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 receives transfer clock pulses φ _H and φ _V generated by a drive circuit 50 based on a vertical synchronizing signal V _syoc and a horizontal synchronizing signal H _syoc from a synchronizing signal generator 51. It is driven to perform the above-mentioned image rubbing 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 41 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, the sawtooth signal generator 4 is supplied with the vertical synchronization signal V _syoc from the synchronization signal generator 51.
2 is based on the vertical synchronization signal _Vsyoc in FIG. 6B.
A sawtooth wave signal SW as shown in FIG. Here, the inclination angle θ of the sawtooth wave signal SW is
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, a rectangular wave signal _SQ as shown in FIG. It has a pulse width π corresponding to T _S and triggers the monostable multivibrator 44 at its falling edge. The monostable multivibrator 44 generates a shutter pulse SP as shown in FIG. 6D every 1 V during the vertical scanning period.
is obtained. And the above Shutter Pulse SP is
It is designed to be outputted via an AND gate 45.

The AND gate circuit 45 is gate-controlled by the operation of the shutter operating 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
It is triggered every time the release switch 71 is closed by operating the shutter operating member 5, and its positive output signal makes the J input of the second flip-flop 47 logic "1". The second flip-flop 47 is supplied with a PG pulse synchronized with the vertical synchronization signal V _syoc as its clock input.
The above J input becomes logic "1" and is triggered by the first PG pulse. Here, the PG pulse is applied to the drive motor 13 of the rotating magnetic disk 12.
The servo system is synchronized with the vertical synchronizing signal V _syoc and is obtained at the same timing as the vertical synchronizing signal V _syoc . The positive output signal of the second flip-flop 47 is supplied to the first flip-flop 46 as a clear signal and is also supplied as the AND gate 45 signal.
Here, the first flip-flop 46 outputs an affirmative output signal of logic "1" from the timing t _S when the release switch 71 is closed to the timing t ₀ of the first PS pulse, as shown in FIG. 6E. . Further, the second flip-flop 47 is
As shown in FIG. 5F, an affirmative output signal of logic "1" is output from the timing _t0 to the timing _t1 of the next PG pulse.

Therefore, from _the AND gate 45, a _shutter pulse as shown _{in FIG} . is output. The shutter mechanism 4 is closed by the shutter pulse from the AND gate 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. Note that the shutter mechanism 4 has a shutter plate 4.
A mechanical structure in which A is driven by a rotary plunger 4B is used. An electronically controllable optical element such as PLZT may be used instead of the shutter plate 4A.

Therefore, the still image recording device according to the present invention includes a solid-state image sensor, a sensor driving means for driving the solid-state image sensor to perform an imaging operation in synchronization with an external periodic signal, and a sensor driving means for driving the solid-state image sensor to perform an imaging operation in synchronization with an external periodic signal; an optical shutter that opens and closes an optical path for imaging light; a shutter driving means that drives the optical shutter to open and close; a shutter operating member that operates the optical shutter; a recording means for recording an image pickup output signal read out on a rotating magnetic disk; a disk driving means for rotationally driving the rotating magnetic disk; The shutter driving means operates the disk driving means and changes the optical shutter from the open state to the closed state after a predetermined exposure time has elapsed based on the timing of the external synchronization signal after the operation of the shutter operating member. and a control means for controlling the sensor driving means to read an imaging output signal from the solid-state image sensor in a state in which the optical shutter is closed; The imaging output signal of a still image read out from the solid-state image sensor is recorded on the rotating magnetic disk. In addition, by reading out the imaging output signal from the solid-state image sensor with the optical shutter closed, the imaging output signal of a still image with extremely good image quality without smearing can be obtained. Obtainable. Furthermore, in the still image recording apparatus according to the present invention, the control means immediately operates the disk drive means in response to a shutter operation signal given by operating the shutter operation member, so that the optical shutter is moved to a predetermined position. The rotational phase and rotational speed of the rotary disk become stable after the exposure time has elapsed until it is closed, and when the optical shutter is closed, the image quality read from the solid-state image sensor is extremely high without smearing. The imaging output signal of a good still image can be reliably recorded on the rotating disk by the recording means.

[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. 4A to 4E are schematic plan views for explaining the signal readout operation from the solid-state image sensor, and FIG.
Figure A shows the movement state of signal charges during the normal gate opening period, Figure 4B shows the movement state of signal charges during the signal readout period, and Figure 4C shows the movement state of the signal charges during the charge sweep period. FIG. 4D shows the movement state of the signal charges for the first field when a frame still image is captured, and FIG. 4E similarly shows the movement state of the 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 operating 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, 70...Control circuit.

Claims (1)

[Claims] 1. A solid-state image sensor, a sensor driving means for driving the solid-state image sensor to perform an imaging operation in synchronization with an external synchronization signal, and an optical shutter for opening and closing an optical path of imaging light irradiated onto the solid-state image sensor. a shutter driving means for driving the optical shutter to open and close; a shutter operating member for operating the optical shutter; and a shutter operating member for operating the optical shutter, and transmitting an imaging output signal read out from the solid-state image sensor in synchronization with an external synchronization signal onto a rotating magnetic disk. a recording device for recording information on a disk, a disk drive device for rotationally driving the rotating magnetic disk, and a disk drive device for immediately operating the disk drive device in response to a shutter operation signal given by operating the shutter operation member; The shutter driving means is controlled to change the optical shutter from an open state to a closed state after a predetermined exposure time has elapsed based on the timing of an external synchronization signal after the operation of the member, and the optical shutter is closed. and a control means for controlling the sensor driving means so as to read an imaging output signal from the solid-state image sensor in a state in which the optical shutter is closed, the still image being read out from the solid-state image sensor in a state in which the optical shutter is closed. A still image recording device characterized in that an output signal is recorded on the rotating magnetic disk.