JPH0799869B2 - Electronic imager - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic imaging device using a charge-coupled device (hereinafter referred to as CCD) as an image sensor, and in particular, photoelectric charges accumulated in a photosensor are used as horizontal line signals. Regarding improvement of means for taking out.

[Prior art]

Generally, a solid-state image pickup device has features such as small size, light weight, long life, and low power consumption. Therefore, it has come to be widely used as an image sensor in place of the conventional image pickup tube.
In particular, solid-state image pickup devices using CCDs, especially CCD image pickup devices of frame interline transfer method (FIL-CCD image pickup device), are very excellent in terms of resolution characteristics, blooming resistance and smear characteristics, etc. This element is often used in electronic image pickup devices.

By the way, generally, in order to obtain a still image suitable for a standard television system using an electronic image pickup apparatus, it is necessary to obtain interlaced video signals for two fields. Particularly, when performing frame recording of a still image in an electronic camera or the like as an electronic image pickup device, it is desirable that each field signal in two fields be exposed at the same time and exhibit a shutter effect. However, in the conventional solid-state imaging device, simultaneous exposure is not performed due to the read-out method and the like. On the other hand, in the FIL-CCD image pickup device, the photocharge storage time is one frame period in both the photosensors on the odd lines and the photosensors on the even lines. In other words, the image is taken with an exposure time of 1/30 second. For this reason, when the subject is moving, the image is blurred. The above-mentioned blurring does not cause much trouble in the case of capturing a moving image, but it becomes a serious problem in the case of capturing a still image. In order to solve such a problem, the accumulation time of photocharges may be shortened so that a so-called element shutter effect can be provided. As means for providing the element shutter effect, for example, there is one described in JP-A-59-33979. However, with the above, the shutter effect for field recording can be obtained, but the shutter effect for frame recording cannot be expected. That is, even if the means described in the above-mentioned JP-A-59-33979 is applied to the FIL-CCD image pickup device to exert the element shutter effect, the exposure timing in the odd field and the exposure timing in the even field And are completely shifted by one field. As a result, when the charge of the odd field and the charge of the even field stored in each photosensor are sequentially read by the interlaced read method as described above to form an image of one frame, the subject is a moving subject. Is a composite of images from two different scenes. In other words, the display content of each horizontal line of the projected image alternately shows the subject images of different scenes, so in an extreme case, it becomes a double image. Thus, the exposure and the element shutter effect by the same time are not exhibited at the same time, and there is a drawback that a still image with good image quality cannot be obtained. Further, in the above-mentioned conventional example, since it is intended for a commonly used interline transfer type CCD image pickup device, there is a drawback that a continuous shutter function in a moving image mode cannot be exhibited.

〔Purpose〕

An object of the present invention is to enable exposure of each field in the same time regardless of whether it is a still image mode or a moving image mode, and moreover, it is possible to effectively exhibit the element shutter effect, and the object is a moving object. Even if it exists, it is an object of the present invention to provide an electronic image pickup device which can easily and stably obtain a still image and a moving image of good image quality without blurring and high resolution.

〔Overview〕

In order to achieve the above object, the electronic image pickup device of the present invention is configured as follows. That is, a plurality of rows capable of generating and storing photocharges are formed so as to form a plurality of rows in a horizontal direction and a plurality of columns in a vertical direction so that an odd line corresponding to an odd field and an even line corresponding to an even field are alternately formed. Photoelectric conversion units in which the photosensors are arranged in a matrix, overflow drains configured to discharge unnecessary charges generated and accumulated in the photosensors, and odd lines generated and accumulated in the photosensors on the odd lines. Two or more cells are arranged corresponding to each photosensor in each column so that the charges and the even line charges generated and accumulated in the photosensors on the even lines can be simultaneously received in each column. The vertical shift register and the odd-numbered charges of the charges of each column transferred to each of the vertical shift registers and respectively shifted. A first horizontal shift register for taking out electric charges as a horizontal line signal of an odd field, and an electric charge for each column which is transferred to each of the vertical shift registers and shifted respectively, and the even line charges are separately accumulated and held. Storage register, a second horizontal shift register for taking out the even line charges accumulated and held in the storage register as a horizontal line signal of an even field, and an odd number taken out by the first and second horizontal shift registers. Means for forming and outputting a horizontal line signal for one frame based on a horizontal line signal for a field and a horizontal line signal for an even field, and a first time point for stopping the continuous unnecessary charge discharging operation by the overflow drain. To start the accumulation of photocharges all at once, A shutter is configured such that an effective exposure time is up to a second time point at which simultaneous batch transfer to the shift register is started, and photocharges transferred after the second time point are shifted by a vertical shift register, Of the charges that have undergone this shift from the third time point after the second time point, the odd line charges are sequentially read out as horizontal line signals of odd fields by the first horizontal shift register, and the even line charges are also read. The even-numbered line charges accumulated and held in the accumulation register are accumulated at the fourth time point after the third time point.
And a timing control means for performing interlaced reading by sequentially reading as horizontal line signals of even fields by the horizontal register.

〔Example〕

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. In the present embodiment, for convenience of explanation, an image pickup element array having 6 rows and 5 columns is illustrated.

In FIG. 1, reference numeral 1 is a photosensor which is composed of an n ⁺ p photodiode or the like and capable of generating and accumulating photocharges. These photosensors 1 are arranged in a matrix with rows in the horizontal direction and columns in the vertical direction so that odd lines corresponding to odd fields and even lines corresponding to even fields are alternately formed. It constitutes a photoelectric conversion unit. Reference numeral 2 is a vertical shift register composed of a two-phase driving CCD provided adjacent to each of the photosensors, and two cells are provided so as to correspond to each photosensor. That is, the pitch of each cell of the vertical shift register 2 is set to 1/2 of the pitch of the photosensor 1, and the photocharges generated and accumulated in each photosensor on the odd line and the even line are simultaneously received at once. It is structured as possible.

A first horizontal shift register 3 is connected to each final shift end of these vertical shift registers 2. This first
An output unit 4 including a floating diffusion and an output transistor circuit is connected to the final shift end of the horizontal shift register 3, and the horizontal line signal of an odd field can be output via a terminal 5. A storage register 6 is connected adjacent to the first horizontal shift register 3. The storage register 6 is arranged so as to correspond to each column of the vertical shift register 2, and is capable of storing all the electric charges B of even lines input through the first horizontal shift register 3. A second horizontal shift register 7 is arranged adjacent to the storage register 6. An output unit 8 having the same configuration as the output unit 4 is connected to the final shift end of the second horizontal shift register 7, and a horizontal line signal of an even field can be output via a terminal 9. There is. Select gate signals are selectively applied to the output sections 4 and 8 so that they are alternately activated. The vertical shift register 2 has shift clocks φV1 and φV2.
Is added to the storage register 6 to shift clock φV.
3, .phi.V4 are added, and shift clocks .phi.H1 and .phi.H2 are commonly added to the first and second horizontal shift registers 3 and 7, and two-phase driving is performed.
Although not shown in FIG. 1, a transfer gate to which a transfer gate signal TG for transferring charges from the photo sensor 1 to the vertical shift register 2 is applied to the photoelectric conversion unit,
An overflow drain for discharging unnecessary charges, a gate electrode for applying a gate control signal OFG to the overflow drain, and the like are provided. Then, while the control signal OFG is applied to the gate electrode, the photosensor 1 is forcibly discharged, and the photosensor 1 is forcibly discharged.
Photoelectric charge is not generated and accumulated in the. Thus, during the predetermined period within one frame where the gate control signal OFG is not applied, photocharges corresponding to the optical image irradiated through the optical system (not shown) are generated and accumulated all at once. .

FIG. 2 is a diagram showing a configuration of a connecting portion of the vertical shift register 2, the first horizontal shift register 3, and the storage register 6. 3 (a) to 3 (d) are diagrams showing the state of charge transfer in the above portion, and FIG. 4 is a waveform diagram showing the operation of the above portion.

As shown in FIG. 2, the vertical shift register 2, the first horizontal shift register 3, and the storage register 6 are all driven by a two-phase clock. Now, it is assumed that the odd line charges A and the even line charges B transferred to the vertical shift register 2 are held under the electrodes to which φV1 is applied as shown in FIG. When the shift clocks .phi.V1 and .phi.V2 are applied at the time point t1, the odd line charges A are transferred to the first horizontal shift register 3 as shown in FIG. The odd line charges A transferred to the first horizontal shift register 3 are then transferred from time t2 to time t3.
During the period up to, it is shifted by the shift clocks φH1 and φH2 and transmitted to the outside. Next, during the horizontal blanking period from time t3 to time t5, when shift clocks φV1, φV2, and φH1 are given as shown at time t4, the even number lines are generated due to the mutual relationship of these shift clocks φV1, φV2, and φH1. The charge B is transferred to the storage register 6 over the first horizontal shift register 3 as shown in FIG. 3 (c). Subsequently, during the period up to time t5, the even line charge B is sent into the storage register 6 as shown in FIG. 3 (d), and the next odd line charge A is stored in the first horizontal shift register 3. Sent to. By repeating the same operation thereafter, the odd line charges A are immediately read by the first horizontal shift register 3 and the even line charges B are accumulated in the accumulation register 6.

Next, the operation of the whole of the present embodiment configured as described above will be described with reference to the charge transfer state diagram shown in FIGS. 5A to 5C and the operation waveform diagram shown in FIG. 6 as appropriate. As shown in FIG. 6, the gate control signal OF of the overflow drain
While G is at H level, the charges of the photo sensor 1 are discharged to the outside through the overflow drain.
Therefore, no photocharge is stored in the photosensor 1 during the above period. When the gate control signal OFG becomes L level, photoelectric charges are accumulated in all the photosensors 1 all at once as shown in FIG. That is, in FIG. 6, a period TX indicated by an arrow is a photoelectric charge accumulation period (exposure time).
Other than that, it is a non-accumulation period and the shutter function is exerted.

Now, just before the exposure, that is, the operation of accumulating the photocharge
Focus on t11. At this time t11, the transfer gate signal TG
Is applied to the transfer gate, φV1 is at the H level and φV2 is at the L level among the shift clocks added to the vertical shift register 2 (not shown) at this timing. Therefore, the charges accumulated in the photosensors on the odd-numbered lines and the photosensors on the even-numbered lines in the period tx until then are simultaneously transferred to the cells of the vertical shift registers 2. Since the selection gate signal .about. / B has the polarity shown in FIG. 6 at the time point t11, the first output section 4 is in the active state and the second output section 8 is in the inactive state. Therefore,
After the time point t11, when the shift clocks φV1 and φV2 are simultaneously applied to each vertical shift register 2 in a predetermined cycle, the odd line charges A among the charges transferred to each vertical shift register 2 become the first charges as described above. The even line charges B, which are output through the output unit 4 via the horizontal shift register 3, are transferred and accumulated in the accumulation register 6. In the period up to time t12, all the odd line charges A are sent out as horizontal line signals, and all the even line charges B are accumulated and held in the accumulation register 6, as shown in FIG. 5 (b). Time t1
When it reaches 2, the selection gate signal ~ / B is inverted. Therefore, the first output section 4 becomes inactive and the second output section 8 becomes active. Therefore, after the time t12, when the shift registers φV3 and φV4 having a predetermined frequency are given to the storage register 6 and the shift clocks φH1 and φH2 are given to the second horizontal shift register 7, they are stored and held in the storage register 6. The even line charge B is output through the second output section 8 through the second horizontal shift register 7 as shown in FIG. 5 (c). During this period, the shift clocks φV1 and φV2 have high frequencies, and the vertical shift register 2 is shifted at a high speed. Therefore, the excess charge in the vertical shift register 2 is stored in the first horizontal shift register 6
It is discharged to the outside via. The discharged electric charge disappears at the first output section 4 which is in the inactive state during this period. In the period from time t12 to time t14, all the even line charges B are transmitted as horizontal line signals. At the time point t13 within the above period, the overflow gate control signal OFG becomes L level, so that substantial generation and accumulation of photocharges of the photosensor 1 are started. Then, at time t14, the transfer to the vertical shift register 2 is performed again.

As described above, in this embodiment, the photocharges corresponding to the optical image are simultaneously generated and accumulated in the photosensors 1 on the odd and even lines corresponding to the odd field and the even field in the predetermined period TX in one frame. , Which are simultaneously transferred to the vertical shift register 2 provided adjacent to each of the photosensors 1,
Of the charges transferred to (1), the odd line charges A are directly read out through the first horizontal shift register 3, and the even line charges B are once accumulated and held in the accumulation register 6 through the first horizontal shift register 3, The accumulated and held even line charge B is read out through the second horizontal shift register 7 after the odd line charge A is read out. As a result, although the image pickup device itself is provided with a shutter function, there is no deterioration in image quality due to the shift of the exposure timing between the odd field and the even field as in the conventional case, and a good still image is obtained. be able to.

Also, if the above-described operation is repeated, a moving image can be picked up. Further, not only continuous driving but also intermittent driving is possible, so that it is possible to carry out single-shot driving for each shutter trigger to perform frame recording. Further, since the storage register 6 only needs to have a capacity capable of storing charges for even fields, the image pickup device can be manufactured in a small size.

FIG. 7 is an operation waveform diagram showing the second embodiment of the present invention. In the second embodiment, the transfer gate signal TG is set to the H level during the period from the time when the vertical drive pulse VD is applied to the light accumulation period TX, and the unnecessary charges of the photo sensor 1 are transferred to the vertical shift register 2. The unnecessary charges are discharged to be discharged by both the overflow drain and the vertical shift register 2. Of course, the charges released to the vertical shift register 2 are discharged to the outside by the high speed shift operation of the vertical shift register 2.

FIG. 8 is an operation waveform diagram of the electronic image pickup apparatus related to the present invention. In the third embodiment, the light accumulation time TX is controlled only by the transfer gate signal TG. That is, during the period in which the photosensor 1 does not need to store light, all the charges accumulated in the photosensor 1 are transferred to the vertical shift register 2 and discharged to the outside by the high speed shift operation of the vertical shift register 2. As a result, the light accumulation time TX is set. Figure 9 shows
It is a block diagram which shows the video camera and electronic camera combined use device as an electronic imaging device of the present invention. In Figure 9
Reference numeral 11 denotes an optical system, and an optical image of a subject incident through the optical system 11 is formed on the photoelectric conversion surface of the CCD solid-state image sensor 12. The CCD solid-state imaging device 12 converts the formed optical image of the subject into an electric signal and outputs it as a horizontal line signal of an odd field and a horizontal line signal of an even field. The output signal is supplied to a signal processing circuit 13 including a color separation circuit and the like via output amplifiers 30A and 30B corresponding to the first and second output sections 4 and 8, respectively. Signal processing circuit
Reference numeral 13 designates the supplied electric signal as a luminance signal Y and a color difference signal R-
Separated into Y and BY, and supplied to the FM modulator 14. FM modulator 14
Applies FM modulation to the luminance signal Y and the color difference signals RY and BY in their respective frequency bands, and supplies them to the first recording amplifier 15A for odd fields and the second recording amplifier 15B for even fields. The recording amplifiers 15A and 15B amplify the FM-modulated signals and give them to the magnetic heads 16A and 16B. The magnetic heads 16A and 16B FM-record the supplied signals on the recording tracks of the magnetic disk 17.

On the other hand, the synchronization signal generator 18 shifts the clock φV1 to the image pickup device 12 via the drive pulse generators 18a and 18b.
In addition to giving φV4, shift clocks φH1, φH2, transfer gate signal TG, overflow gate control signal OFG
Are directly applied to the image pickup device 12. At the same time, the timing pulse of the vertical drive signal VD, the horizontal drive signal VH, etc. is given to the signal processing circuit 13. Further sync signal generator 18
Supplies a sync pulse for matching the operation timing of the imaging system with the operation timing and phase of the recording system to the sync detector 19 as one input.

Sync detector 19 is a PG pulse provided as the other input,
That is, the pulse from the rotation phase detection pulse generator 20 attached to the magnetic disk 17 is compared with the synchronization pulse from the synchronization signal generator 18, and the rotation speed and phase of the magnetic disk 17 always match the operation timing of the imaging system. Such a signal is given to the motor drive circuit 21. Motor drive circuit 21
Drives and controls the disk drive motor 22 based on the signal given from the detector 19. As a result, the magnetic disk 17
In the steady state, the motor rotates at a constant speed of 3600 RPM and one field image is recorded during one rotation.

The recording gate circuit 23 is triggered by the trigger pulse TG generated when the recording command switch 24 interlocked with the release button of the camera is turned on, and corresponds to one field period based on the synchronizing pulse from the synchronizing signal generator 18. A write pulse WG having a width is applied to the recording amplifiers 15A and 15B with a time shift, and the recording amplifiers 15A and 15B are activated only during that period.

In FIG. 9, reference numeral 25 denotes an encoder, and the signal processing circuit 13
The luminance signal Y and the color difference signals RY and BY, which are the outputs of the above, are converted into, for example, an NTSC signal, which is sent to the viewfinder 26 and at the same time sent from the output terminal 27 to a VTR or the like. Thus, the viewfinder 26 can monitor the content of the image pickup.

The synchronization signal generator 18 is supplied with a mode selection command signal from the operation mode selection circuit 28. The operation mode selection circuit 28 sends a command signal for selecting a predetermined operation mode by, for example, a manual operation from the outside of the camera to select a moving image mode (repetitive recording operation) and a still image mode (single-shot recording mode). Switching selection is performed. The output amplifier 30A receives the signal from the sync signal generator 18 via the inverter 29,
B is given the above-mentioned signal directly, so that it has the same function as that of the output units 4 and 8 described above.

Thus, according to the apparatus shown in FIG. 9, it is possible to easily and stably obtain a moving image or a still image with good image quality.

〔The invention's effect〕

According to the present invention, the exposure of each field can be performed in the same time regardless of whether it is in the still image mode or the moving image mode, and the element shutter effect can be effectively exerted. It is possible to provide an electronic imaging device that can easily and stably obtain a still image and a moving image of good image quality without blurring and high resolution even for a certain subject.

[Brief description of drawings]

1 to 6 are views showing a first embodiment of the present invention, FIG. 1 is a block diagram showing a configuration of an electronic image pickup device, and FIG. 2 is a vertical shift register 2 and a first horizontal shift. Register 3
And FIG. 3 (a) to FIG. 3 (d) are diagrams showing a state of charge transfer in the above portion,
FIG. 4 is a waveform diagram showing the operation of the above portion, and FIG.
(C) and FIG. 6 are a charge transfer state diagram and an operation waveform diagram showing the operation of the entire first embodiment, and FIG. 7 is a second diagram of the present invention.
8 is an operation waveform diagram showing an embodiment of the present invention, FIG. 8 is an operation waveform diagram of an electronic image pickup apparatus relating to the present invention, and FIG. 9 is a block showing a video camera / electronic camera combined apparatus as the electronic image pickup apparatus of the present invention. It is a figure. 1 ... Photo sensor, 2 ... Vertical shift register, 3,7
...... First and second horizontal shift registers, 4,8 ...... First and second
Output section, 11 …… Optical system, 30A, 30B …… Output amplifier.

Claims (1)

[Claims] 1. Photoelectric charge generation and storage in which a plurality of rows are formed in the horizontal direction and a plurality of columns are formed in the vertical direction so that odd lines corresponding to odd fields and even lines corresponding to even fields are alternately formed. A photoelectric conversion unit in which a plurality of possible photosensors are arranged in a matrix, an overflow drain configured to discharge unnecessary charges generated and accumulated in the photosensor, and a photoelectric sensor generated and accumulated in the photosensor on the odd line. Two or more cells are assigned to each photosensor in each column so that the odd-line charges and the even-line charges generated and accumulated in the photosensors on the even lines can be simultaneously received in each column. The vertical shift registers provided, and the odd number of charges in each column transferred to each of the vertical shift registers and shifted. A first horizontal shift register for taking out the in-charge as a horizontal line signal of an odd field; and a first horizontal shift register for accumulating and holding the even lines of the charges of each column transferred to each of the vertical shift registers and respectively shifted. Storage register, a second horizontal shift register for taking out the even line charges accumulated and held in the storage register as a horizontal line signal of an even field, and an odd number taken out by the first and second horizontal shift registers. Means for forming and outputting a horizontal line signal for one frame based on a horizontal line signal for a field and a horizontal line signal for an even field; and a first time point for stopping the continuous unnecessary charge discharging operation by the overflow drain. To start the accumulation of photocharges all at once. A shutter is configured such that the effective exposure time is up to a second time point at which simultaneous batch transfer to the direct shift register is started, and the photocharges transferred after the second time point are shifted by the vertical shift register. , Of the charges that have undergone this shift from the third time point after the second time point, the odd line charges are sequentially read out as horizontal line signals of odd fields by the first horizontal shift register, and the even line charges are also read. Is accumulated and held in the accumulation register, and at the fourth time point after the third time point, the accumulated and held even line charges are sequentially read out by the second horizontal register as a horizontal line signal of an even field. An electronic image pickup device comprising: a timing control means for performing interlaced read-out. .