JPH0591416A - Solid-state image pickup device and its driving method - Google Patents

Abstract

PURPOSE:To improve the dynamic image resolution and to prevent the power loss by reading alternately the electric charge out of two types of photoelectric conversion elements only in a monitoring mode and using the electric charge read out of one of two types of photoelectric conversion elements for reproduction of images. CONSTITUTION:The photodiodes 3 arranged in each column are sorted in four types, i.e., A1, B1, C1 and C2. In a still image pickup mode, the electric charge is successively read out from the photodiodes of four types A1-B2. Then the electric charge is read out from the photodiodes 3 of A1 and A2 only in a monitor or movie mode. That is, the electric charge is read out from the photodiode 3 of A1 in a first V period and sent to a vertical VCCD 4 and then the electric charge is read out from the photodiode A2 in the next V period respectively in a monitoring mode. Meanwhile the electric charge of the photodiodes 3 of B1 and B2, for example, that are not read out nor sent to the VCCD 4 are left as they are. Then the overflowed electric charge is absorbed by a base board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device,
In particular, the present invention relates to a method for driving a high-resolution solid-state imaging device having a large number of photoelectric conversion elements and a solid-state imaging device for implementing the method.

[0002]

2. Description of the Related Art In recent years, solid-state image pickup devices have been remarkably developed mainly for video cameras. High resolution is one of the directions, and 2 million pixels to 4 million for high-definition television (HD-TV), mechanical measurement, astronomical observation, etc.
A solid-state image sensor with, 000,000 pixels has been developed.

However, at present, only an image pickup device having 400,000 pixels or less is put to practical use for a color camera having 525 vertical scanning lines which is a mainstream for consumer use.

In consideration of applications such as a still (still image) video camera, an image input device, and an electronic overhead projector (OHP), a device having a larger number of pixels is required in the 525 vertical scanning line system.

The applicant has studied the optimum number of pixels based on theoretical calculation and image simulation.
It was concluded that the number of pixels of about 0,000 pixels is sufficient for the above applications. Based on this conclusion, various proposals have been made for a CCD color sensor having about 800,000 pixels.

It has been clarified that for an image having an aspect ratio of about 3: 4 in the vertical and horizontal directions, a preferred form of arranging 800,000 pixels is about 1000 in the vertical direction and about 800 in the horizontal direction.

That is, the photodiodes are arranged in a matrix of about 1000 in the vertical direction and about 800 in the horizontal direction, and the vertical C for advancing the charges in the vertical direction is adjacent to each column.
CD (VCCD) columns are provided, and horizontal CCDs (H) for horizontally transferring charges to the output terminals of these VCCD columns are provided.
CCD) rows are provided.

In order to read out electric charges from about 1000 pixels arranged in the vertical direction, for example, a VCCD including two transfer cells per row is arranged.

In order to read image information in a short time, it has been proposed to classify vertical photodiodes into four types and read charges from two types of photodiodes at a time. That is, assuming that the vertical scanning period is V, information from all pixels can be read in the period of 2V. In this case, due to the limitation of horizontal charge transfer, two HCCDs are provided, and two kinds of charges are simultaneously transferred by the two HCCDs.

By the way, in a system using two HCCDs, the intensity of the image signal varies depending on which HCCD is used for transfer. Particularly in a color image pickup device having a three-plate structure, the level difference between image signals appears as a flicker phenomenon.

In order to prevent such a phenomenon, the applicant of the present invention uses one HCCD and uses a period 4 which is four times the vertical scanning period V.
A method of reading all image information by V was proposed. According to this method, it is possible to reproduce a highly accurate still screen.

By the way, at the time of monitoring before capturing a still image (including a movie mode for capturing a moving image), the image information is taken in over a period of 4V, and signal processing is further performed to reproduce the image. Is not preferable in terms of dynamic resolution and processing time. Therefore, in order to perform image reproduction in a short period of time, it is desirable to perform NTSC image reproduction at the time of monitoring.

FIG. 2 shows a conventional high resolution solid-state image pickup device. FIG. 2A schematically shows the configuration of the image pickup device. A large number of photodiodes 3 are arranged in a matrix. For example, about 800 photodiodes are arranged in one row in about 1000 rows. The photodiodes 3 in each row are
From the top, they are classified into four types, A1, B1, A2, and B2.

A VCCD 4 is formed adjacent to the photodiode 3 in each column. The VCCD 4 has two transfer cells per row, and 4 rows and 8 cells are one unit. The transfer cell is configured by disposing an insulating electrode on the semiconductor transfer path. One unit cell has V1, V2, V3, V4, V5, V2, V from the top.
6, the control signal of V4 is given.

The charge accumulated in each photodiode is transferred from the photodiode to the VCCD 4 by applying a high voltage to the corresponding cell of the adjacent VCCD 4. The charges transferred to the VCCD 4 are Vc by selectively applying a predetermined voltage to the electrodes of the VCCD 4 sequentially.
It is transferred vertically downward in the CCD 4.

An HCCD 101 is commonly and adjacently arranged at the lower end of each VCCD 4. The charges transferred downward through each VCCD 4 are transferred to the HCCD 10 according to a control signal.
Forwarded to 1.

A shift gate SG103 capable of selectively transferring charges is arranged adjacent to the HCCD 101, and another HCCD 102 is provided below the shift gate SG103.
Are arranged.

The shift gate SG103 and the HCCD 102 arranged below the shift gate SG103 are omitted in a device for reading out the charges accumulated in the photodiode 3 in a period of 4V.

FIG. 2B shows a mode in which the charges accumulated in all the photodiodes 3 are read out in the period of 2V. Of all the photodiodes 3, the charges of the photodiodes A1 and A2 are read in the same V period, and B1 is read in the next V period.
And the charges of B2 are read out. By performing such reading, the charges of all the photodiodes 3 can be read during the 2V period.

However, in this mode, the charges accumulated in the photodiodes A2 and B2 are the same as those of the photodiode A1.
And the charge accumulated in B1 are compared to shift gate SG1
It receives more attenuation than the transfer loss when transferring 03. Further, when the characteristics of the HCCDs 101 and 102 are different, this difference in characteristics is further superimposed.

FIG. 2C illustrates a mode in which all the charges of the photodiode are read during the period of 4V. The charge of the photodiode A1 is read during the first V period, the charge of the photodiode A2 is read during the next V period, and the next V
The charge of the photodiode B1 is read during the period, and the charge of the photodiode B2 is read during the fourth V period.
According to such a charge reading mode, since all the charges are read out through the HCCD 101, it becomes easy to keep the charge reading characteristics uniform.

By the way, when capturing a still image, the HD-T
Even in an apparatus for reading an image by the V method, a simple and quick imaging method is desired at the time of monitoring when determining the composition or at the time of movie shooting of a moving image.

FIG. 3 is a diagram for explaining a monitor mode (including a movie mode) in the 4V reading method. In the monitor mode, it is desired to perform the NTSC system monitor in order to simply and quickly reproduce the image.

FIG. 3A illustrates a case where an NTSC system monitor is performed using a 500-line system monitor. When the signals from the photodiodes A1 and A2 are supplied as image signals in the first 2V period, the image formed corresponds to the photodiodes A1 and A2. In the next 2V period, the charges from the photodiodes B1 and B2 are supplied and a corresponding image is formed.

By the way, the image 105a based on the photodiodes A1 and A2 and the image 105b based on the photodiodes B1 and B2 are different in the position in the vertical direction for one scanning line. Therefore, when an image by the 4V reading method similar to that at the time of capturing a still image is reproduced using a 500-line monitor, flicker occurs in the vertical direction.

FIG. 3B shows a case where an image is monitored by a 1000-line monitor. If the signal of 4V read method is directly supplied to the 1000-line monitor,
Charges from the photodiodes A1, A2, B1 and B2 are supplied to form an image 106 of one screen.

In order to collect this image signal, a 4V period is required, and when all the image signals are reproduced by the HD-TV system, it is necessary to temporarily store the signal and further process it. Therefore, the 1000-line monitor causes a problem that the dynamic resolution is low and the processing time is long.

At the time of monitoring, it is desired to use the NTSC system of 500 lines in order to simply and quickly reproduce the image. In order to reproduce the NTSC system image of 500 lines by using the imaging device of 1000 lines, FIG.
A method as shown in (D) has been proposed.

In the system shown in FIG. 3C, the accumulated charges are read out in the same manner as in the still image pickup, but only the charges from the half photodiodes A1 and A2 are used for reproducing image formation. That is, the output of the CCD is A
1, A2, B1, B2 are supplied in this order, and writing to the memory is also performed by directly writing the read image signal.

However, the monitor signal is performed by repeatedly reading only the signals from the photodiodes A1 and A2 without using all the written image signals.
That is, when the image signal is read from the photodiode A1 and written in the memory, the previously stored image information A2 is stored.
When the signal of the photodiode A2 is written in the memory next, the information of A1 written immediately before is read from the memory.

Next, even during the period in which the image signals B1 and B2 should be read, the image signals A2 and A1 are read from the memory to reproduce the 500-line monitor image in which vertical flicker is prevented.

When the image signal from the photodiode A1 is written in the memory, the signal of A2 is read out,
The case of reading A1 while writing the image signal A2 has been described. However, when reading the image signal from the photodiodes A1 and A2, the signal is directly supplied to the monitor and the image signal is read from the photodiodes B1 and B2. Alternatively, the previously stored image signals A1 and A2 may be read from the memory.

In this system, vertical flicker can be prevented, but it is difficult to increase the dynamic resolution.

FIG. 3D is a diagram for explaining the pixel-mixing type readout method. In the first field, which is the first V period, the image signals from the photodiodes A1 and B1 are read and mixed to form a monitor signal. Next V
In the second field, which is the period, the image information from the photodiodes A2 and B2 is read and mixed to form a monitor signal. In this way, the information of all pixels is read during the 2V period.

According to this method, it is possible to obtain a monitor image with no vertical jitter and high dynamic resolution. Further, since all the accumulated charges are read during the 2V period, the charge accumulation period is 2V, and the charge amount is doubled due to pixel mixing, so that the normally obtained charge amount (that is, sensitivity) is within the 4V period (accumulation period 4V). This is similar to the case of taking out image information from each pixel.

When pixel information is read out by performing pixel mixing, the charges accumulated in the two photodiodes are combined and transferred by the HCCD. Therefore, the driving voltage of the HCCD does not correspond to twice the saturated charge. Don't

That is, when light of high intensity is applied, charges close to saturation charge are accumulated in each photodiode in a short time. When these charges are mixed, it is necessary to transfer twice the saturated charge by the HCCD. H with a drive voltage that can transfer the saturation charge of one photodiode
When the CCD is driven, charge transfer leakage occurs.

Therefore, it is necessary to double the swing voltage of the driving voltage of the HCCD. C
Since the CD structure has a capacitance C that cannot be ignored, power loss cannot be ignored when the swing voltage is doubled and charges are transferred at high speed.

[0039]

As described above,
In the conventional 1000-line image pickup apparatus, if an attempt is made to perform a 500-line monitor by the NTSC system, there arise problems such as vertical flicker, lower dynamic resolution, longer processing time, and power loss.

An object of the present invention is to provide an image pickup apparatus capable of reproducing a high-resolution still image, by which vertical jitter is not generated at the time of monitor, high dynamic resolution and low power loss can be reproduced. is there.

[0041]

According to a method for driving a solid-state image pickup device of the present invention, charges accumulated in a large number of four types of photoelectric conversion elements arranged in a matrix are associated with each column of the photoelectric conversion elements. A solid state which takes in a plurality of columns of vertical CCDs arranged in parallel, sequentially transfers the charges in each vertical CCD to a horizontal CCD commonly connected to the vertical CCDs, and sequentially transfers the charges in the horizontal CCDs to read out signal charges. A method of driving an image pickup device, which comprises a step of alternately transferring only the charges of two types of photoelectric conversion elements to a vertical CCD at the time of monitoring, and the remaining 2 at the time of monitoring
The electric charges of the photoelectric conversion elements of the types are not read, and the electric charges that overflow are swept away as they are.

[0042]

Since the charges from only two types of photoelectric conversion elements are alternately read during monitoring, one screen (claim) can be read in a 2V period, so that the dynamic resolution is high.

Further, since the read charges from one type of photoelectric conversion element are used for image reproduction, the charges transferred by the HCCD have the same saturated charges as when the still image was picked up. Therefore, it is not necessary to increase the HCCD drive voltage, and power loss can be prevented.

Since signals from only two types of photoelectric conversion elements are used for image reproduction, vertical jitter does not occur.

[0045]

1 shows a basic embodiment of the present invention. Figure 1
FIG. 1A schematically shows the configuration of a solid-state imaging device. A large number of photodiodes 3 are arranged in a matrix, and the photodiodes 3 arranged in each column are classified into four types A1, B1, A2 and B2. A corresponding VCCD 4 is arranged adjacent to each column of the photodiodes 3. VCCD
Two transfer cells are formed in each row 4 of the photodiode.

The HCCD 5 is connected to the lower end of the VCCD 4, and the charges transferred in the vertical direction through the VCCD 4 can be transferred in the horizontal direction. An amplifier 8 is connected to the output end of the HCCD 5.

The charges from the four types of photodiodes A1, A2, B1 and B2 are sequentially read out at the time of capturing a still image, but only the charges from the two types of photodiodes, for example, A1 and A2 are read out at the time of monitoring or movie.

FIGS. 1B and 1C schematically show such a charge reading method. That is, in reading from the photodiode to the VCCD in the monitor mode, the charge from the photodiode A1 is read during the first V period, and the charge from the photodiode A2 is read during the next V period. In this way, only the charges from the two types of photodiodes with a cycle of 2 V are VCCD.
4 is read.

The charges not read out to the VCCD 4, for example, the charges of the photodiodes B1 and B2 are left as they are,
The overflowing charges are sucked out to the substrate.

In the still mode, the photodiode A1 is read in the first V period, the photodiode A2 is read in the next V period, the photodiode B1 is read in the next V period, and the fourth V period is read. The photodiode B2 is read.

Therefore, the saturated charge amount of the charges to be transferred by the HCCD becomes equal when the still image is picked up and when the monitor is performed. Therefore, it is not necessary to increase the drive voltage of the HCCD 5, and power loss can be prevented.

Further, since the monitor image is constructed using only two kinds of electric charges, vertical jitter does not occur. Also,
Since one frame image is formed in the 2V period, the dynamic resolution can be increased.

Since the charge accumulation period at the time of monitoring is 2V, which is half that of the charge accumulation period at the time of capturing a still image, which is 4V, the sensitivity becomes half. In order to guarantee this difference, an amplifier which selectively performs double amplification may be connected to the amplifier 8.

Hereinafter, more specific examples of the present invention will be described. FIG. 4 is a block diagram showing a camera head unit of the image pickup apparatus according to the embodiment of the present invention.

In FIG. 4A, the camera head unit 1
Is a CCD image pickup device 11, and a correlated double sampling preamplifier 12 for amplifying an output signal from the CCD image pickup device 11 while reducing noise, and a signal from the preamplifier 12 as a signal output to the camera shown in FIG. A 75Ω driving circuit 13 for supplying to the control unit is included.

Further, the camera head unit 1 has a horizontal drive signal HD and a vertical drive signal V from the camera control unit 2 shown in FIG.
PLL circuit 1 for receiving D and generating a synchronization signal
5, these synchronizing signals HD, VD and the camera control unit 2
Control unit 16 for receiving a horizontal drive pulse and a vertical drive pulse, and a horizontal drive circuit for receiving the horizontal drive pulse and generating a horizontal drive signal for driving the HCCD, a vertical drive pulse Received,
It includes a vertical drive circuit 18 for generating a vertical drive signal for driving the VCCD.

The vertical drive circuit 18 generates a drive signal for capturing and transferring an image from four types of photodiodes at the time of capturing a still image, and a drive signal for reading out charges from only two types of photodiodes, for example, A1 and A2, at the time of monitoring. To occur.

The control unit 16 includes a timing generator, a control CPU and the like. Further, the camera head unit 1 includes a power supply unit 20 for supplying electric power to each circuit included in the camera head unit 1.

FIG. 4B shows a modification of the circuit shown in FIG. This is suitable when, for example, a circuit of an image pickup device that performs 4V reading at the time of capturing a still image and performs pixel mixing at the time of monitoring is partially modified and used.

That is, the control signal V1 from the control unit 16
.About.V4 are given to the vertical drive circuit 18 as they are, field shift signals FS1 to FS4 for instructing the charge reading from the photodiodes are given only two of them directly from the control unit 16 to the vertical drive circuit 18, and the remaining two are mask circuits. Give through 19.

The mask circuit 19 passes the field shift signal FS as it is at the time of capturing a still image, but the mask circuit 19 blocks two field shift signals at the time of monitoring.

In this way, at the time of still image pickup, 4
The charges of all types of photodiodes are read, and the charges of only two types of photodiodes are read during monitoring.

FIG. 5 is a block diagram showing the camera controller 2. The signal output supplied from the camera head unit 1 is
It is supplied to the gain control amplifier 21 and amplifies the set gain. Gain control amplifier 21
Is supplied to the A / D conversion circuit 23 via the gamma processing circuit 22, becomes a digital signal, and is output to the memory section 24.
Is supplied to.

The memory section 24 stores the supplied digital signal. The image signal read from the memory unit 24 is
Is converted into an analog signal via the D / A conversion circuit 25,
Is output.

The timing generator 29 generates a horizontal drive pulse HD, a vertical drive pulse VD and other control signals at a predetermined timing, and also generates control signals for the main CPU 28 and the gamma processing circuit 22.

The main CPU 28 receives the switch signal from the external switch 32 and outputs the mode signal to the memory control unit 2.
7 and the camera head unit 1. Memory control unit 2
7 receives the mode signal and changes the bank switching mode when the image signal is stored in the memory section 24. Main CPU
28 also supplies the gain control amplifier 21 with a gain switching signal for giving a predetermined gain depending on the mode.

The power supply 30 supplies a power supply voltage to various circuits in the camera control section 2. By the circuits shown in FIGS. 4 and 5, the image signal accumulated in the CCD device 11 at the time of capturing a still image is read in the 4V period, and the memory unit 24
Accumulated in. In the monitor mode, the CCD
Of the charges accumulated in the device 11, only two predetermined types of charges are read out and displayed on the monitor 31.

Hereinafter, each part of the image pickup apparatus shown in FIGS. 4 and 5 will be described in more detail. FIG. 6 shows the structure of the CCD device. 6A is a plan view and FIG. 6B is a partial cross-sectional view. In FIG. 6A, the CCD device 1
Reference numeral 1 includes photodiodes 35 arranged in rows and columns, VCCDs 36 for taking in charges from the photodiodes 35 and transferring them in the vertical direction, and HCCDs 37 for transferring charges transferred from a plurality of VCCDs 36 in the horizontal direction.

Each row of the photodiodes 35 is divided into four types A1, B1, A2, B2 in order from the top as shown in the figure, and each type of photodiode corresponds to one field image. Adjacent to each photodiode row, VCCD
36 are arranged, and the VCCD 36 has two transfer cells for one row of photodiodes. VCCD 36 is φVA
Charges are transferred by 6-phase driving of 1, φV2, φVB1, φV4, φVA2, and φVB2.

The plurality of VCCDs 36 are connected to the HCCD 37 at one end thereof. That is, the charge taken into the VCCD 36 from the photodiode 35 is VC
The CD 36 is transferred in the vertical direction, transferred to the HCCD 37, and then transferred in the HCCD 37 in the horizontal direction. HCCD
37 is a four-phase drive signal φH1, φH2, φH3, φH
Driven by four. The output of the HCCD 37 is output via the amplifier 39.

FIG. 6B shows the structure of the photodiode formed on the surface of the substrate and the vertical overflow drain formed below the photodiode. A p well 42 is formed in the surface portion of the n-type semiconductor substrate 41. The p-well 42 has a shallow first p-well 1pw and a deep second p-well 1pw.
The p wells 2pw are distributed.

An n-type region 43 is formed on the first p-well 1pw.
Are formed to form a photodiode. An n ⁻ type region 44 is formed in the vicinity of the n type region 43 at a predetermined interval to form a charge transfer path of the VCCD. The p ⁺ type region 48 is a channel stop region. An insulating electrode 45 and a light shielding mask 46 are formed on the n ⁻ type region 44 forming the charge transfer path.

Incident light is incident on the n-type region 43 forming a photodiode. A reverse bias voltage is applied between the p-well region 42 and the n-type substrate 41 by the DC power supply 50.

When the charges are accumulated excessively by the incident light, n
Electrons from the mold region 43 overflow into the n-type substrate 41. In this way, the photodiodes B1, B
Even when the electric charge is not read from 2, the photodiode B
The charges overflowing 1 and B2 are sucked out to the substrate 41.

FIG. 7 shows a timing chart of the control signal in the monitor mode for monitoring the image to determine the composition. The field switching signal FI has a pulse-shaped waveform that changes alternately for each field. The external switch signal always keeps a value of "0" because the shutter is not pressed in the monitor mode.

The mode signal is "0" in the monitor mode and "1" in the still mode. The gain switching signal has the same pattern as the mode signal, and has a value of "0" in the monitor mode and "1" in the still mode.

The field shift signals FS1 to FS4 are
These are instruction signals for reading the charges from the photodiodes A1 and B2, respectively, but in the monitor mode,
Only the field shift signal FS1 for reading charges from the photodiode A1 and the field shift signal FS3 for reading charges from the photodiode A2 generate read signals, and the field shift signals FS2, FS4 for reading charges from the photodiodes B1 and B2 are
It has a fixed value and does not instruct reading.

Therefore, in the monitor mode, the charges from the photodiode A1 and the photodiode A2 are alternately read during the V periods which are successively continuous.

The camera drive signal alternates between field A1 and field A2. Further, in the monitor mode, since recording is not performed, the recording signal REC is "0".

FIG. 8 shows the waveform of the drive signal for capturing the image signal in the field A1. VCCD
When the voltage of the transfer cell adjacent to the photodiode is set to a predetermined height, the accumulated charge is taken into the VCCD from the photodiode.

The upper part of FIG. 8 shows the waveform of a six-phase signal for driving the VCCD. At time t4, drive signal φV
Since A1 is at a high level, the accumulated charge is taken in from the photodiode A1. At other times, there is no high level drive signal.

That is, electric charges are taken into the VCCD from one type of photodiode A1 during the 1V period and sequentially transferred in the vertical direction in the VCCD during each horizontal blank period, and the charges in the HCCD are rapidly transferred during the next horizontal scanning period. Transferred.

FIG. 9 is an enlarged waveform diagram showing the portion indicated by the broken line in FIG. VCCD drive signals φVA1, φVA
2, φV2, φVB1, φVB2, φV4 change as shown to transfer charges in the vertical direction in the VCCD.

The times t1 to t1 shown in FIG. 8 and FIG.
The potential in the VCCD at 0 is shown in FIG.

At time t4, the driving voltage φVA1 becomes high level, and the charge of the photodiode A1 becomes VCCD.
Is taken into.

At the next time t5, each of the taken-in charges spreads over three transfer cells. After that, from time t6 to t
The electric charge taken in 11 is contracted backward by 1 cell, then extended forward by 1 cell, contracted backward again by 1 cell, and the same operation is repeated and transferred to the right side in the figure by the scale insect method.

Although the driving of the field A1 that takes in electric charges from the photodiode A1 has been described, the similar electric charges are taken in and transferred from the photodiode A2 in the field A2 as well. FIG. 10 shows the field A2
7 shows a drive signal waveform for capturing image data in FIG.

FIG. 12 shows a signal waveform when the shutter is driven to capture a still image and the external switch 32 shown in FIG. 5 is turned on. The external switch 32 generates an external switch signal which is "1" for a predetermined period. When the external switch signal changes from "0" to "1", mode switching for converting the camera drive signal is performed in the field next to the rising edge of the signal. This mode switching is 1
It ends in the V period. At the same time as the start of mode switching,
The mode signal rises and the still mode is displayed.

Further, the gain switching signal rises simultaneously with the mode signal, and the gain control amplifier 2 shown in FIG.
Set the gain of 1 to half of the monitor mode gain.
That is, in the still mode, the charge accumulation period is 4
Since it becomes V, twice as much electric charge is accumulated as in the monitor mode of 2V, and therefore the sensitivity difference is adjusted by the gain control amplifier 21.

The field shift signals FS1 to FS4 are
In monitor mode, two of them, FS1 and FS3
Only the field shift signals are instructed, but when the mode is switched, all field shift signals FS1 to FS are sent.
4 alternately indicates the field shift. That is, one type of photodiode is read during the V period, and charges from all four types of photodiodes are read during the subsequent 4V period.

After the mode switching is completed, at least 4 V (or 4 n
V) is cleared. In the illustrated case, the recording mode has started after the 4V clear operation. In the recording mode, the photodiode A1 according to the recording signal REC,
The charges of A2, B1 and B2 are sequentially read in the period of 4V and recorded in the memory.

FIG. 13 shows a drive signal waveform for reading out the charges of the photodiode A1 in the first V period.

At time S1, the drive signal φA1 becomes high level, and the charge from the photodiode A1 becomes VCC.
VC in each subsequent horizontal blank period
It is transferred vertically through the CD. Further, during the horizontal scanning period, the charges in the VCCD are stopped, and the charges in the HCCD are transferred at high speed in the horizontal direction.

FIG. 14 shows a control signal of a field for reading out the photodiode A2. At time S8, the drive signal φA2 becomes high level, and the charge from the photodiode A2 is taken in. Photodiode A2 to VCCD
The electric charge taken in by VCCD is
Transferred vertically inside. Also, during the horizontal scanning period, V
The charges in the CCD are stopped, and the charges in the HCCD are transferred at high speed in the horizontal direction.

FIG. 15 and FIG. 16 show the waveforms of drive signals in the fields for extracting charges from the photodiodes B1 and B2, respectively.

In FIG. 15, drive signal φB1 attains a high level at time S6, and the accumulated charge is taken in from photodiode B1. Further, in FIG. 16, the drive signal φB2 becomes high level at time S10, and the accumulated charge is taken in from the photodiode B2 to the VCCD.
The transfer of these charges is the same as described above.

As described above, A1, A2, B1,
In a CCD device including a large number of four types of B2 photodiodes, in the still mode, all charges are read out in a 4V period to form a high-resolution image, and in the monitor mode, only two types of photodiodes are used, one type at a time for 2V. Charge is taken in with a period as a cycle, VCCD is transferred, and transferred to HCCD. Therefore, power loss can be prevented and a monitor image with high dynamic resolution can be obtained.

In the monitor mode and the still mode, the gain of the gain control amplifier provided in the camera controller changes by a factor of 2, so that the difference between the storage periods of 2V and 4V can be compensated.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to these. For example,
It will be apparent to those skilled in the art that various modifications, improvements, combinations and the like can be made.

[0100]

As described above, according to the present invention,
The charges corresponding to the unit photoelectric conversion elements may always be transferred by the HCCD, and the HCCD driving signal has the same condition in the still mode and the monitor mode. Therefore, power loss can be prevented.

Further, in the monitor mode, since the image signal is taken in at the cycle of 2V, the dynamic resolution can be increased.

Since the two types of image signals to be captured can be captured from a fixed position, it is possible to prevent jitter.

[Brief description of drawings]

FIG. 1 shows a basic embodiment of the present invention. FIG. 1A is a schematic diagram showing the configuration, and FIGS. 1B and 1C are schematic diagrams for explaining reading of accumulated charges in the monitor mode and the still mode.

FIG. 2 shows a conventional technique. FIG. 2A is a schematic plan view showing the configuration, and FIGS. 2B and 2C are conceptual diagrams for explaining charge reading.

FIG. 3 is a diagram illustrating a monitor mode of a 4V read method in a conventional technique. FIG. 3A is a schematic diagram for explaining a reproduced image on a 500-line monitor, and FIG.
FIG. 3C is a schematic diagram illustrating a reproduced image on the 0-line monitor.
FIG. 3 is a conceptual diagram for explaining double reading, and FIG. 3D is a conceptual diagram for explaining pixel mixed reading.

FIG. 4 is a block diagram of a camera head unit of the image pickup apparatus according to the embodiment of the present invention. FIG. 4A shows a configuration example thereof, and FIG. 4B shows a modification example.

FIG. 5 is a block diagram showing a camera control unit of the image pickup apparatus according to the embodiment of the present invention.

FIG. 6 shows the configuration of the CCD device shown in FIG. 5 in more detail. FIG. 6A is a schematic plan view and FIG. 6B is a partial sectional view.

FIG. 7 is a waveform diagram showing a control signal waveform in a monitor mode.

FIG. 8 is a waveform diagram for explaining image signal acquisition in the monitor mode.

FIG. 9 is a waveform diagram for explaining image data transfer in monitor mode.

FIG. 10 is a waveform diagram showing control signals of other fields in the monitor mode.

FIG. 11 is a potential diagram for explaining acquisition and transfer of image data in the VCCD in the monitor mode.

FIG. 12 is a waveform diagram showing a control signal waveform in a still mode.

FIG. 13 is a drive signal waveform diagram of an A1 field in a still mode.

FIG. 14 is a drive signal waveform diagram of an A2 field in a still mode.

FIG. 15 is a drive signal waveform diagram of a B1 field in a still mode.

FIG. 16 is a drive signal waveform diagram of a B2 field in still mode.

[Explanation of symbols]

 1 Camera Head 2 Camera Control 3 Photodiode 4 VCCD 5 HCCD 8 Amplifier 11 CCD Device 12 Preamplifier 13 Drive Circuit 15 PLL Circuit 16 Control Unit 17, 18 Drive Circuit 19 Mask Circuit 20 Power Supply 21 Gain Control Amplifier 22 Gamma Processing Circuit 23 A / D conversion circuit 24 memory unit 25 D / A conversion circuit 27 memory control unit 28 main CPU 29 timing generator 30 power supply 31 monitor

Claims (4)

[Claims] 1. Charges accumulated in a large number of photoelectric conversion elements of four types arranged in a matrix are taken into a plurality of columns of vertical CCDs arranged corresponding to each column of the photoelectric conversion elements, and each vertical CCD is captured. A method for driving a solid-state image pickup device in which charges in a CCD are sequentially transferred to a horizontal CCD commonly connected to a vertical CCD, and charges in the horizontal CCD are sequentially transferred to read out signal charges. A method for driving a solid-state image pickup device, which comprises a step of alternately transferring only the charges of photoelectric conversion elements to a vertical CCD, and a step of sweeping away the overflowing charges without reading the charges of the remaining two types of photoelectric conversion elements during monitoring. 2. The method of driving a solid-state image pickup device according to claim 1, further comprising a step of amplifying a signal read from the horizontal CCD by a factor of 2 during a monitor. 3. A plurality of four types of photoelectric conversion elements arranged in a matrix, a plurality of columns of vertical CCDs arranged corresponding to each column of the photoelectric conversion elements, and a plurality of columns of vertical CCDs. 1 commonly connected to each end
In the horizontal CCD of the row and in the monitor mode, a means for generating a control signal that alternately transfers only the charges of the two types of photoelectric conversion elements to the vertical CCD, and the charges of the remaining two types of photoelectric conversion elements do not read and overflow. Solid-state imaging device including means for sweeping away charges. 4. The solid-state imaging device according to claim 3, wherein the charge sweeping-out means includes a barrier-type charge passage formed between the photoelectric conversion element and the substrate.