JPS60125079A - Electronic still camera - Google Patents

Abstract

PURPOSE:To eliminate the need for a shutter device and to attain reduction in size and cost by controlling the operation condition of an image pickup device. CONSTITUTION:A subject image is formed on the image pickup surface of a solid-state image pickup element 8 through a lens 1 all the time. Then, the solid- state image pickup element 8 is driven normally with the control signal from an operation condition control signal generator 12; so that charges generated in a photoelectric converting element array 12 corresponding to the subject image are all discharged through a charge absorbing array 24. Equivalently, no incident light from the subject is guided to the solid-state image pickup element. Namely, the shutter is held closed. On the other hand, the control signal from the operation condition control signal generator 12 varies from low to high during the photography of the subject and the solid-state image pickup element 8 is so driven by a driving circuit 13 as to accumulate charges generated in the photoelectric converting element array 21.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an electronic still camera that takes and records still images.Conventional structure and problems thereof Imaging means for capturing a subject image formed by an imaging optical system The conventional basic configuration of an electronic still camera is to convert the still image signal into a still image signal and store this still image signal in a recording device.
As shown in the figure. This electronic still camera is configured so that a subject image (not shown) is formed on the imaging surface of an image sensor 3 by a lens 1, but normally (when the subject is not being imaged) the shutter 2 is closed and the shutter 2 is closed. Incident light from the subject is blocked and is not guided to the image sensor 3.

When photographing an object, when the release switch 7 is pressed, the shutter 2 is opened for a required period of time set by the shutter speed setting device 6, and incident light from the object is guided to the image sensor 3. A charge corresponding to this incident light is generated and accumulated in the image sensor, and this charge is read out as a video signal in synchronization with the synchronization signal from the synchronization signal generator 6, and is recorded in the recording device 4 to produce a still image. The shooting of - is completed. Conventional electronic still cameras with the above configuration use a method of controlling the period of incidence of incident light, similar to conventional cameras using silver halide film, to obtain instantaneous images of the subject. In addition, a shutter device is required to control the blocking and passing of incident light, which is one of the factors that hinders miniaturization and cost reduction of devices.

OBJECTS OF THE INVENTION The present invention eliminates the drawbacks of the conventional electronic still camera described above, does not require a shutter device like the conventional one,
Therefore, it is an object of the present invention to provide an electronic still camera that can be made smaller and lower in cost, and that can obtain frame images.

Structure of the Invention The present invention provides a solid-state image sensor having an imaging region including a photoelectric conversion element array and a charge transfer element array, and an accumulation region including a charge transfer array; a lens for forming a subject image on the image sensor; In an electronic still camera equipped with a release switch that commands photographing of a subject, a command signal from the release switch starts generating and accumulating charges in the photoelectric conversion element array of the solid-state image sensor in accordance with the subject image, and After a period of time has elapsed, the charges accumulated in either odd or even horizontal pixel columns of the photoelectric conversion element column are first transferred to an accumulation region and temporarily accumulated, and then the charges are accumulated in the remaining horizontal pixel columns. The charges temporarily accumulated in the vertical transfer element array in the imaging area are transferred to the vertical transfer element array in the imaging area, and the charges temporarily accumulated in the storage area and the vertical transfer element array in the imaging area are transferred to the video signal of the first field and the video signal of the second field, respectively. By reading out the signal as a signal and storing it in the recording section, a still image of an arbitrary exposure period can be obtained as a frame image without using a shutter device.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows an example of the basic configuration of the present invention, and the solid-state imaging device shown in FIG. 8 is as shown in FIG.
A photoelectric conversion element array 21 as disclosed in Japanese Patent No. 104377. Charge absorbing row 24.Charge transfer element row 22.
This is a solid-state image sensing device in which a part of the readout register is constituted by a 23° charge storage region 26.

In FIG. 2, a subject image is always focused on the imaging surface of the solid-state image sensor 8 by the lens 1.

Normally (when the subject is not being photographed), the solid-state image sensor 8 is operated by a control signal from the operating condition control signal generator 12 to absorb all the charges generated in the photoelectric conversion element array 21 corresponding to the subject image. 24, and due to the same constraints, no incident light from the subject is guided to the solid-state image sensor 8, that is, the shutter in the conventional example shown in FIG. 1 is in a closed state. There is.

On the other hand, when photographing a subject, when the release switch 7 is pressed and photographing is commanded at time t in the timing chart of FIG. Rising time t2 of VB (in this example, the first vertical blanking signal) (waveform a in Figure 4) At time t3, which is an exposure time TB set by the exposure time setting device 11, an operating condition control signal is generated. The control signal from the device 12 changes from a Low state to a High state, and the solid-state image sensor 8 is driven by the drive circuit 13 so that the charge generated in the photoelectric conversion element array 21 is accumulated. Specifically, the charge absorbing operation of the charge absorbing column 24 of the solid-state image sensor 8 is stopped.

During this period, the shutter in the conventional example shown in FIG. 1 is in an open state.

Then, at the moment when the vertical blanking pulse VB rises (or after a slight delay), a control signal from the charge transfer control signal generator 14 is used to select which of the many elements in the photoelectric conversion element row is odd or even. A pulse as shown in FIG. 4C is applied to an electrode (not shown) that transfers the charge of a horizontal picture element column to the adjacent charge transfer element column 22, and the photoelectric charge of either an odd or an even horizontal picture element column is applied. The charge of the conversion element is transferred to the charge transfer element array 22. Here, in order to simplify the explanation later, an odd horizontal pixel array is assumed. This charge is then transferred to the storage region 26 and temporarily accumulated by applying a transfer pulse to the charge transfer element array 22 and the storage region 26 for a period from t to t6 as shown in FIG. 4d. . After this charge transfer is completed, the charges in the photoelectric conversion elements of the remaining even-numbered horizontal pixel columns are transferred by applying the pulse shown in FIG. The data is transferred to the element array 22 and temporarily stored there.

After the blanking period of the vertical blanking pulse ends (time t7), a transfer pulse is applied to the storage region 26 by the control signal from the charge readout control signal generator 16 (period t7 to t8 of waveform e in FIG. 4). waveform), the charges temporarily accumulated in the accumulation region 26 are read out and the fourth
A video signal of the first field is formed as shown in the waveform of waveform f in the period t7 to t8 in the figure. Then, during the period from t9 to t1° within the vertical blanking period starting at time t8, data is transferred to the vertical transfer element array 22 and the storage region 26 as shown in the waveform e in FIG. 4, similarly to the period from t4 to t6. A pulse is applied, and the charges temporarily accumulated in the vertical transfer element array 22 are transferred to the accumulation region 26. And this charge is
In the next vertical effective scanning period (t, 1 to t12),
- 18), a transfer pulse is applied to the second accumulation region (the waveform from '11 to t12 of the waveform e in Figure 4) and read out, and the first feed 7-do of the waveform in Figure 4 is read out. The video signal undergoes signal processing in the signal processing circuit 9, is guided to a recording device, and is recorded. For this purpose, the recording control signal generator 16
Then, as shown in FIG. 4q, a recording control signal that rises during the vertical blanking period from t2 to t7 and falls during the vertical blanking period that rises at t12 is generated, and this recording control signal The recording device 10 may be configured to perform a recording operation during a period in the high state.

Furthermore, considering the signal charges that form the video signals of the first and second fields, the accumulation time, that is, the exposure time, of the signal charges that form the video signals of the first field is Ts, and the video signal of the second field is The accumulation time of the formed signal charges is TS+TW, which is a different value. However, TW is the time t2 when the signal charges forming the first field video signal are transferred from the photoelectric conversion element array 21 to the vertical transfer element array 22, and the time t2 when the signal charges forming the second field video signal are transferred from the photoelectric conversion element array 21 to the photoelectric conversion element array 22. This is the time difference from time t6 at which the data is transferred from the vertical transfer element array 21 to the vertical transfer element array 22. Therefore Tw
No problem occurs when Ts is sufficiently small, but Tw
When it can no longer be ignored with respect to Ts, the reproduced image becomes unsightly if the video signals of the first and second fields are recorded as they are. To prevent this, in the signal processing circuit 9,
The amplification degree A1 for the video signal of the first field and the amplification degree A1 for the video signal of the first field,
If the amplification degree A2 for the video signal of the field is made different and maintained in the following relationship, the first output from the signal processing circuit 9
．． The video signal of the second field has no level and no problem occurs.

With the above steps, photographing and recording of the subject is completed, and a still image with the required exposure time can be obtained as a frame image without using a shutter.

The traffic of signals between each block in FIG. 2 will be summarized and explained again.

The photographing command signal from the release switch 7 is guided to the operating condition control signal generator 12, and the timing is adjusted with the vertical blanking signal VB (waveform a in FIG. 4) guided from the synchronizing signal generator 6 to perform this operation. The condition control signal generator generates an operating condition control signal as shown in FIG. This control signal is guided to a drive circuit 13 to change the driving conditions of the image sensor 8, while being guided to a charge transfer control signal generator 14, a vertical blanking signal guided by a synchronization signal generator 6, and various other signals. Charge transfer control signals as shown in FIG. Furthermore, the operating condition control signal is also guided to the charge readout control signal generator 16 and the recording control signal generator 16, and is outputted at a predetermined timing by the vertical blanking signal VB guided from the synchronization signal generator 6, respectively, as shown in FIG. A charge readout control signal shown in e and a recording control signal shown in FIG. 4q are generated. Further, this operating condition control signal is also guided to the signal processing circuit 9, and as described above, the amplification degree in the signal processing circuit is controlled by the first field and the second field.
It is used as a timing pulse to make the field video signal different.

The synchronization signal from the synchronization signal generator 5 is then transmitted to the drive circuit 13. Signal processing circuit 9. It is guided by a recording device 10 to maintain synchronization of the system.

In the above explanation, when the subject is not being photographed, the charge absorbing array 24 of the solid-state image sensor 8 is always operated so as not to accumulate the charge corresponding to the subject image. The present invention is not affected in any way by operating the normal video camera as disclosed in Japanese Patent Publication No. 104377. This has the effect that the signal can be used for the View 7 eye radar.

Effects of the Invention As described above, according to the present invention, a subject can be photographed at any exposure time by simply controlling the operating conditions of the imaging device and without using a shutter device, which is required in conventional electronic still cameras. As a result, a still image for one frame can be obtained, contributing to the miniaturization and cost reduction of electronic still cameras, and its practical value is high.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of a conventional electronic still camera, FIG. 2 is a block diagram showing the basic configuration of an electronic still camera according to an embodiment of the present invention, and FIG.
FIG. 4 is a schematic diagram schematically showing the structure of a solid-state image sensor used in the electronic still camera shown in the figure, and FIG. 4 is a signal waveform diagram for explaining the operation of the electronic still camera of the present invention shown in FIG. DESCRIPTION OF SYMBOLS 1... Lens, 7... Release switch, 8... Solid-state image sensor, 9... Signal processing circuit, 10... Recording device , 12...
- Operating condition control signal generator, 14... Charge transfer control signal generator, 16... Charge readout control signal generator, 16... Recording control signal generator. Figure 1 Figure 3

Claims (3)

[Claims] (1) a solid-state image sensor having an imaging region including a photoelectric conversion element array and a charge transfer element array, and an accumulation region including a charge transfer element array; a release switch for instructing imaging of a subject; a first means for starting generation and accumulation of electric signals in accordance with the subject image in a photoelectric conversion element array of the solid-state image sensor according to a command signal from the release switch; After an arbitrary period of time (T8) has elapsed after the start of charge generation and accumulation, the charges accumulated in either odd or even horizontal pixel columns among the photoelectric conversion element columns are transferred and accumulated to the accumulation region, and the remaining charge is transferred and accumulated. a second means for sequentially transferring and accumulating the charges accumulated in the horizontal pixel columns in the charge transfer element column in the imaging region; and first, transferring the charges temporarily accumulated in the accumulation region to the first field a third means for outputting the charge outputted as a video signal of the first field as a video signal of the second field; An electronic still camera equipped with means for performing signal processing on a second field video signal and storing it as a still image signal for one frame. (2) The first means is started at a time Ts before the start of an arbitrary vertical blanking period after the generation of the photographing command signal, and the second means is performed within the vertical blanking period. An electronic still camera according to claim 1, characterized in that: (3) In the second means, the time delay between the charge transfer of the first horizontal pixel column and the charge transfer of the remaining horizontal pixel columns is T.
The electronic device according to claim 1, wherein the amplification factor of the signal processing unit for the second field video signal is Ts/(T B + Ty) times the amplification factor for the first field video signal, where w is the amplification factor for the second field video signal. still camera.