JPH0331034B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photographic imaging device having an imaging element.

[Description of prior art]

In recent years, solid-state imaging devices such as CCD type and MOS type have been used in various fields.

Furthermore, large-area solid-state imaging devices using amorphous silicon or the like have also been proposed.

These solid-state imaging devices can obtain image information corresponding to a subject by controlling the storage time of image information.

In recent years, it has become possible to construct electronic photographic cameras using such solid-state image sensors. For example, as shown in Japanese Unexamined Patent Publication No. 49-52912, there is a device that controls the amount of incident light by coupling a shutter to a CCD driven at the TV cycle.

In addition, there is a method such as Japanese Patent Application Laid-open No. 140544/1983 by the present applicant, in which the storage amount is controlled only by the storage time of the CCD without using a shutter.

[Problem that the invention seeks to solve]

However, in the former case, the storage time of the CCD is a fixed period, so even if you limit the exposure time with a shutter, dark current will occur during light shielding, and the S/N of the stored image will increase.
The problem was that it deteriorated.

In addition, the latter accumulates within the CCD for the required amount of time, which greatly reduces the dark current, but on the other hand, since light is constantly incident during transfer related to readout, smear occurs and strong light On the other hand, there was a risk that an image similar to multiple exposure would be formed.

The present invention aims to eliminate such drawbacks of the prior art, and in particular, aims to provide an imaging device with little dark current and smear, and without exposure unevenness due to shutter.

[Means for solving problems]

In order to achieve such an object, the imaging device of the present invention includes an imaging means for converting an optical image into an electrical signal, a release means for instructing the imaging means to take a still image, and an operation in response to the release means. a shutter that changes over a predetermined period of time between a fully closed state and a fully open state so as to selectively make an optical image incident on the image pickup means; A signal generating means generates a signal in response to full opening, and an accumulation operation is started by completing clearing of the electrical signal in the imaging means in response to the signal generating means, and then, after a preset time elapses, the above-mentioned It has a control means for ending the accumulation operation of the imaging means and starting closing of the shutter, and thereafter reading out the electrical signals accumulated by the imaging means, and a recording means for recording the electrical signals read out by the control means. .

[Effect]

This configuration eliminates the need for extra accumulation, thereby preventing the generation of dark current, and also eliminates the occurrence of smear since light is shielded by the shutter during transfer. Furthermore, it is possible to obtain an imaging device that can prevent exposure unevenness that occurs during the period from when the shutter is fully closed to fully opened.

〔Example〕

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment in which the present invention is applied to a single-lens reflex camera to which an exchangeable video adapter can be attached.

LS is the imaging lens, AS is the aperture, QM is the quick return mirror, FS is the focus plate, CL is the condenser lens, PR is the pentaprism, EL is the eyepiece lens, SP is the photoelectric conversion element for photometry, and MT is the current for exposure display. ST is the shutter, FP is the film positioning rail, and CT is the connection terminal on the camera side. The items described below constitute the replacement video adapter, where SM is an area-type solid-state image sensor as an imaging means, DM is a drive circuit for the solid-state image sensor as a readout means, AM is a replacement back cover, and CM is a replacement video adapter. Connector terminals on the replacement video adapter side, CB1 and CB2 are connection capes, CK1 is a video recording device as a recording means, and CK2 is a display device such as a television receiver.

Normally, the film is placed on the film position setting rail surface FP via a back cover with a film pressure plate (not shown), but in this figure, the solid-state image sensor SM of the replacement video adapter is placed on the focal plane. The camera is configured to transmit electrical information between the camera and the adapter via the connection terminals CT and CM.

FIG. 2 is a diagram showing an embodiment of the electric circuit of the camera of the present invention. This figure assumes a shutter-priority single-lens reflex camera, where LM is a photometry circuit consisting of a photoelectric conversion element SP for measurement, an operational amplifier MP1 for photometry, and a logarithmic conversion element LD, and SV is a photometry circuit that contains film sensitivity information, TV is an exposure information setting circuit for setting shutter speed information.

The outputs of LM, TV, and SV are summed by operational amplifier OP1 to output aperture information, and the aperture display ammeter
The aperture value is displayed on the MT, and the aperture control circuit
The aperture is set using magnet Mg1 via ASK.

The measurement power switch SW1 is turned on by pressing the first step of the shutter release button (not shown), which serves as a release means for instructing still image capture, and the power E1 is supplied to the photometry and display circuit system, and exposure information is displayed. . Next, by pressing the shutter release button to the second stage, the photographing power switch SW2 is turned on, and power supply to the aperture and shutter control circuits is started.

Shutter time setting means Shutter time setting resistor VR1 linked to TV, time integration capacitor C1, count switch SW5 which turns off almost at the same time as the shutter starts to open, and shutter trigger circuit SHT are time settings for shutter control. form a circuit. When the aperture control is completed via magnet Mg1, the quick return mirror QM goes up, the shutter starts to open, SW5 is turned off, and the time-setting control of the shutter control time-setting circuit starts, and when the potential of C1 reaches a certain value or more, The shutter trigger circuit SHT is reversed and the shutter control magnet Mg
2 is turned off, the shutter closes and the exposure when using normal film is completed. Next, a circuit consisting of transistors Tr1 and Tr2, resistors R1 to R3, and a switch SW6 that is turned on when the shutter is fully opened and turned off when the shutter is closed or wound is when the timed control of the shutter control timed circuit starts when the replacement video adapter is installed. This is a circuit for controlling switching.

Connect terminal CT1 between camera and adapter,
When connected via CM1; CT2, CM2; CT3, CM3;, the pull-down resistor on the adapter side
Since transistor Tr2 is turned on due to _R10 ,
Transistor Tr1 is also turned on, and both terminals of _C1 are shorted. Therefore, even if the count switch SW5 is turned off in synchronization with the beginning of the shutter opening, _C1 will not be charged.

When SW6 is turned on in conjunction with the full opening of the shutter, transistor Tr1 is turned off, and time-setting control of the shutter control time-setting circuit is started. At the same time, it is fixed by the drive circuit DM of the solid-state image sensor via the connection terminals CT3 and CM3. Accumulation of image information corresponding to the subject in the image sensor SM is started. When the potential of _C1 exceeds a certain value, the Schmitt trigger circuit is activated.
SHT is reversed, and the storage of image information in the solid-state image sensor SM is completed by the drive circuit DM of the solid-state image sensor via the connection terminals CT2 and CM2, and the shutter control magnet Mg2 is turned off. Exposure is complete.

Furthermore, in the present invention, when using the replacement video adapter, the film sensitivity information on the camera side is switched to the sensitivity of the solid-state image sensor. In other words, when the replacement video adapter is connected to the camera in FIG. The transistor Tr15 is turned on by the pull-down resistor _R10 , so the transistor Tr16 is turned on, and the transistor Tr17 is turned off via the inverter IN, and the film sensitivity information SV is turned on.
Instead, the sensitivity information VS of the solid-state image sensor is input to the operational amplifier OP1, and an aperture suitable for the sensitivity of the solid-state image sensor is set.

FIG. 3 is a diagram showing another embodiment of the shutter control method in the camera of the present invention, in which the aperture is determined after the shooting power switch SW2 is turned on when the replacement video adapter is attached, and the shutter is fully opened until the shutter is fully opened. This is a method in which the time of the shutter control is delayed in advance through a delay circuit, and the output of the delay circuit is used to start time-setting control of the shutter control time-setting circuit.

The capacitor C ₂ , the resistor R ₂₀ , and the transistor Tr6 constitute a reset circuit for initially resetting the charge of the time setting capacitor C ₃ of the delay circuit in synchronization with the turning on of the photographing power switch SW2.
_R1 is a resistor for controlling the time-fixing current of the delay circuit. Only when a replacement video adapter is installed, transistor Tr5 is turned on, and after the time-fixing current flows and the shutter is fully opened, the potential of _C3 changes to the resistor R. ₂₃ and _R24 , comparator CP1 is inverted, transistor Tr7 is turned on via resistor _R25 , transistor Tr1 is turned off, time control of the shutter control time circuit is started, and the shutter control becomes constant. After a certain period of time, the Schmitt circuit SHT is reversed, the shutter is closed, and the exposure to the solid-state image sensor is completed.

In this embodiment, a shutter-priority type camera has been described, but it goes without saying that the present invention can be similarly applied to a shutter control time circuit of an aperture-priority type camera that controls the shutter speed based on a photometric calculation value. stomach. Furthermore, although the shutter control time-setting circuit is illustrated as an analog one, the same applies to a digital time-setting circuit using a counter.

FIG. 4 shows a specific embodiment of a solid-state imaging device SM suitable for the present invention.

A ₁ ,…, A _o ;…; Z ₁ ,…, Z _o are photosensitive pixel parts having a charge storage function, CA ₁ ,…, _Co ;…; CZ ₁ ,
..., CZ _o is an integral clear gate for clearing the charge accumulated in the photosensitive pixel section, FA ₁ , ...,
FA _o ;...; FZ ₁ ,..., FZ _o is a vertical analog shift register VS ₁ ,..., for transferring the image information accumulated in the photosensitive pixel section corresponding to the subject.
The charge transfer gate for transferring to _VSO , HS is an analog shift register for horizontal charge transfer, and these vertical and horizontal shift registers are driven by clock pulses Vφ ₁ , Vφ ₂ , Hφ ₁ , Hφ ₂ be done. The image information transferred to the vertical shift register is transferred via the vertical shift register and the horizontal shift register in a known manner, and the image information transferred to the right end of the horizontal shift register is transferred to the field effect transistor (FET) FC1, Through a charge voltage conversion circuit consisting of FC2 and resistors R ₃₀ to R ₃₂
It is sequentially output as voltage information from the VF terminal.

When the shutter on the camera side is fully opened, SW6 is turned on and transistor Tr1 is turned off, so the time-setting control of the shutter control time-setting circuit is started, and as the shutter is opened, the CT3 terminal becomes zero level. The ICG terminal, which had previously discharged (cleared) unnecessary charges prior to shutter opening via the drive circuit DM, is inverted to the low level side, and the integral clear gates CA ₁ ,...CA _o ;...; CZ ₁ ,
..., CZ _o is turned off, and the photosensitive pixel portion A ₁ , ..., A _o ;
…; Accumulation of image information corresponding to the subject is started at Z ₁ , …, Z _o . When the timed control of the shutter control timed circuit is completed, the shutter trigger circuit SHT
is reversed, the CT2 terminal becomes high level, and the drive circuit
A pulse is generated at the SH terminal via DM, and the charge transfer gates FA ₁ ,..., FA _o ;...; FZ ₁ ,..., FZ _o are turned on, and the image information accumulated in the photosensitive pixel section is transferred to the analog shift register VS ₁ , ...The image information is transferred to the _VSO , storage of the image information is completed, and reading of the image information is started.

In this embodiment, a video adapter is assumed, but it goes without saying that the entire adapter may be included in the camera.

〔effect〕

As described above, according to the present invention, the accumulation time is variably controlled by the imaging means, and the shutter performs exposure only during this accumulation time, so that the dark current can be greatly reduced, and there is no smearing and high Capable of recording quality still images. Furthermore, it is possible to obtain an imaging device that can prevent exposure unevenness that occurs during the period from when the shutter is fully closed to fully opened.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an outline of an embodiment of the present invention, and FIG.
The figures show an example of a circuit related to a camera according to the present invention, FIG. 3 shows a second example of the same circuit, and FIG. 4 shows a second example of the same circuit.
The figure is a diagram showing an example of the configuration of an imaging means applicable to the present invention. ST...Shutter, SM...Imaging means, VR1, C1
...Time setting circuit for exposure control, Mg2...Magnet for shutter closing, DM...Image sensor drive circuit.

Claims (1)

[Claims] 1. Imaging means SM that converts an optical image into an electrical signal
a release means SW2 that instructs the imaging means to take a still image; and a release means SW2 that operates in response to the release means and operates between a fully closed state and a fully open state so that an optical image is selectively incident on the imaging means. a shutter ST that changes over a predetermined period of time; signal generating means SW6, Tr7 that generates a signal in response to the shutter being fully opened after starting driving the shutter in response to the release means; The accumulation operation is started by completing the clearing of the electrical signal in the image pickup means, and then, after a preset time has elapsed, the accumulation operation of the image pickup means is ended and the closing of the shutter is started. Control means VR1, C1, for reading out the accumulated electrical signals
An imaging device comprising: SHT, DM; and recording means CK1 for recording electrical signals read out by the control means.