JP2000050174A - Image pickup device and its driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand a dynamic range of an image pickup device by plural times of exposure and to achieve expansion of the dynamic range by simple structure while enabling interlaced scanning by making an exposing part of a first period and an exposing part of a second period coexist in an image pickup panel. SOLUTION: An XY address type solid-state imaging device is used. In addition, the exposing part of the first period and the exposing part of the second period coexist in the image pickup panel. Exposure of EX (1) for (1/609-1/2000) seconds when a photoelectric charge in a first row of the imaging device is read and exposure period of EX (2) for 1/2000 seconds when a photoelectric charge of a second row of the imaging device is read are superposed in this device. In addition, pieces of data for two times of image pickup area alternately read to floating diffusion by utilizing efficiency of a two-dimensional address. Drive by a series of control becomes effective even in three or more times of the exposure by setting an output period of a video signal as one horizontal operation period/exposure frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus having a photoelectric conversion element, and more particularly, to an image pickup apparatus having a plurality of types of exposure times of a photoelectric conversion element for expanding a dynamic range and a driving method thereof.

[0002]

2. Description of the Related Art In recent years, imaging devices have been widely used in digital cameras for still images, video cameras for moving images, and the like.
However, the dynamic range of an image sensor used in a video camera is narrower than that of a silver halide photograph, and when the image is backlit, overexposure and underexposure occur due to the narrow dynamic range. In order to solve this problem, for example, there is a method of performing dynamic exposure by performing exposure twice. In this method, a saturated pixel signal of a screen imaged with a normal exposure time of 1/60 second is used for a high-speed shutter operation (for example, 1
/ 1000 seconds).

A known example of such exposure is disclosed in Japanese Patent Application Laid-Open No. Hei 4-189082 by Hashimoto. According to this publication, in a CCD type imaging device that expands a dynamic range by performing a plurality of exposures, in order to obtain an imaging device with high sensitivity and no degradation in sensitivity, the first exposure with a different exposure amount is performed. By simultaneously reading out the signals from the second exposure, the sensitivity is high without reducing the effective aperture area of the light receiving element, and 2
It is described that good dynamic resolution can be obtained because exposure (photoelectric conversion) is performed at the same time and exposure timing does not shift.

[0004] Further, it has a storage portion twice or more as large as the number of light receiving pixels, and has one vertical video period for the data based on the first storage time,
A known example of a method of transferring data according to the second accumulation time to the accumulation unit during the vertical blanking period is disclosed in Japanese Patent Application Laid-Open No. 9-284654 by Itakura et al.

The storage units of the image data used in this type of known example each have an amount equal to or more than one field data. This is due to the fact that in recent years, the imaging device used as the mainstream is a CCD, and the transfer of imaging data in the vertical direction is performed sequentially.

[0006]

FIG. 16 and FIG. 1 show an example of a procedure of two exposures and transfer of the image data when a CCD is used as an image sensor, taking Japanese Patent Application Laid-Open No. 9-284654 as an example.
7 will be described.

First, one vertical video period (1/60 second) is set to 2
Evenly divide the first accumulation period (1/120 second) 108 and the second
And the first signal charge accumulated in the photoelectric conversion unit 1 of the light receiving unit at the instant when the first accumulation period 108 ends is shifted by the shift pulse 121 to the vertical transfer unit of the light receiving unit. It is moved to 102 (FIG. 16B).
Next, during the next vertical blanking period 106, the first signal charges stored in the first storage period are transferred to the transfer pulse 12.
2 to the first storage unit 3-1 (FIG. 16)
(C)). Next, at the moment when the second accumulation period 109 ends within the same blanking period, the photoelectric conversion unit 101 of the light receiving unit
The second signal charges stored in the vertical transfer unit 102 of the light receiving unit are moved by the shift pulse 123 (FIG. 16).
(D)). Next, the second signal charge stored in the second storage period 109 is transferred to the first storage unit 3-1 by the transfer pulse 124, and at the same time, the second signal charge is transferred from the first storage unit 3-1 to the second storage unit 3-1.
(FIG. 16 (e)). Thereafter, the photocharge of the second storage unit 3-2 is output from the horizontal transfer unit 104 to the output unit 105 by the horizontal line transfer pulse 117 every horizontal transfer period (FIG. 16F).

[0008] In this manner, one vertical video period is divided into a plurality of sections, and the signal charges stored in the photoelectric conversion section are moved to the vertical transfer section during each of the divided periods. It is stated that the driving method of the solid-state imaging device having a high dynamic range can be obtained.

However, in the CCD as an image pickup device, for example, after the signal charges accumulated by receiving light in the photoelectric conversion unit 101 are moved to the vertical transfer unit 102, the signal charges are sequentially transferred by the supplied transfer pulse 124. Skip reading is not possible.

Therefore, as described above, the readout of the image data by a plurality of exposures uses a storage unit equal to or more than one field data.

According to the present invention, it is possible to perform interlaced scanning which was impossible in the above-described conventional example,
It is an object of the present invention to expand the dynamic range of an imaging device and to achieve a simple configuration.

[0012]

In order to solve the above-mentioned problems, an XY address type solid-state image sensor is used as an image sensor of the present invention. In this type of imaging device,
Interlaced scanning and, consequently, block reading are possible. Therefore, in the case of reading out image data obtained by a plurality of exposures, it is possible to multiplex exposure periods. In addition, as a result, the data can be temporarily stored with a necessary capacity, and can be configured with a smaller amount than in the related art.

Further, the image pickup apparatus and the driving method according to the present invention are characterized in that the exposed portion in the first period and the exposed portion in the second period are mixed in the image pickup panel.

Further, in the imaging apparatus and the driving method according to the present invention, the signal from the imaging data detecting means by the exposure in the first period and the signal from the imaging data detecting means by the exposure in the second period are interlaced. Is read by the following.

Further, the image pickup apparatus and the driving method thereof according to the present invention are characterized in that before the exposure of the first period is completed in the image pickup panel, the image pickup data by the exposure of the second period is read.

Further, the image pickup apparatus and the driving method according to the present invention include an image pickup element for photoelectrically converting a subject image and outputting a video signal according to two-dimensional designation, and a circuit for electrically controlling the image pickup element to read the video signal. Image data obtained by exposing the photoelectric conversion element used for the image sensor in a first period, and image data obtained by exposing the photoelectric conversion element in a second period different from the first period. And reading means for reading image data exposed from the pixels during the first period by interlaced scanning.

Further, in the imaging apparatus according to the present invention, the photoelectric conversion element for exposing the photoelectric conversion element during the first period and the photoelectric conversion element for exposing the photoelectric conversion element during the second period are provided separately on the same substrate. It is characterized by the following.

Further, the image pickup apparatus according to the present invention comprises a plurality of two-dimensionally arranged photoelectric conversion elements, a transfer of charges of the plurality of photoelectric conversion elements, a reset of the photoelectric conversion elements, and a photoelectric conversion element. In the imaging device that reads out a video signal by selecting the above, one vertical scanning period is divided into a plurality of
An exposure unit for exposing the photoelectric conversion element for each of the plurality of times and a reading unit for independently selecting a signal charge stored in the photoelectric conversion element and reading a video signal are provided.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a diagram showing an example of the configuration of an image pickup apparatus of the present invention using an amplification type solid-state image pickup device. Reference numeral 6 denotes a lens that forms an image of a subject on the amplification type solid-state imaging device 33. The formed optical signal is converted into an electric signal by the solid-state imaging device 33. Reference numeral 5 denotes an A / D converter for converting the electric signal into a digital signal. And
Reference numeral 7 denotes a signal processing unit for processing an image signal and converting the image signal into an appropriate format. Reference numeral 39 denotes a central processing unit (hereinafter abbreviated as CPU) which controls the imaging apparatus. Reference numeral 38 denotes a timing generator (hereinafter abbreviated as TG) which generates operation timing of each functional block according to a control signal from the CPU 39. ).

FIG. 2 shows an example of the structure of the amplification type solid-state imaging device 33. FIG. 2 shows a matrix for performing photoelectric conversion, accumulation, amplification, and transfer of 4 × 3 incident light as an example. Here, a photodiode (hereinafter abbreviated as PD) 70 is an element for photoelectrically converting and accumulating incident light, and a cell amplifier 71 has a configuration as shown in a dotted frame 71 in FIG.

In FIG. 3, reference numeral 81 denotes a floating diffusion (hereinafter, referred to as FD) having the charge accumulated in the PD 70 as a floating structure with the gate of the amplifying MOS transistor 83 as a floating structure.
The transfer MOS transistor serves as a potential barrier operation transfer gate for transferring the transfer MOS transistor. Also, 8
Reference numeral 0 denotes a reset MOS transistor for resetting the charge of the FD 70 by the same operation. Further, 82 is provided as a MOS transistor for line selection. The gates of these MOS transistors are connected to a transfer signal line 74 for transferring the charge of the PD 70, respectively.
The reset signal line 76 for resetting the FD and the selection signal line 75 are connected.

Here, the electric charge accumulated in the PD 70 is transferred to the FD reset by the reset signal line 76 from the vertical drive unit 72 through the transfer gate 81 turned on by the transfer signal line 74, and is transferred by the selection signal line 75. The signal is amplified by the source follower MOS transistor 83 via the selected selection MOS transistor 82, and is read out by the read line 79.
And is stored in the capacitor 85 as shown in FIG. Subsequently, a column selection signal is applied from the horizontal driving unit 73 to the column selection transistors 77 (1) to 77 (4), and a time-series video signal is output to the signal output line 78.

Further, from the point of time when the operation of each pixel is analyzed, exposure from different periods can be performed will be described below. In FIG. 4A, first, before the completion of the first exposure period, the FD reset / MOS transistor 8 is started.
0 is turned ON, and the FD is reset. Thereafter, the FD reset is released by turning off the reset / MOS transistor 80. Then, the photocharge 90 accumulated in the cathode of the PD 70 during the first exposure period is transferred to the FD provided at the gate of the amplification MOS transistor 83 by turning on the charge transfer MOS transistor 81. After that, the charge transfer MOS transistor 81
Is OFF. At this point, the PD 70 is ready for the second exposure. The charge stored in the FD is amplified MO
By the source follower function of the S transistor 83 and the ON of the line selection MOS transistor 82, the read line 79
Is read out. In FIG. 4A, the gate TX of the transfer MOS transistor 81 is set to the OFF level, the photoelectric charge is accumulated in the PD 70, the gate SEL of the selection MOS transistor 82 is turned off, and the reset MOS transistor 80 is set.
The gate R is turned off from the state where the gate R is turned on,
The example which turns on the gate TX and shifts to the state which turned on the gate SEL is shown.

Subsequently, before the second exposure period is completed, F
D is reset. As shown in FIG. 4B, this operation first turns on the FD reset transistor 80.
And reset the FD. Thereafter, turning off the reset transistor 80 completes the reset of the FD.

FIG. 5 is a timing chart when the image pickup driving of the present invention is performed using the image pickup system shown in FIGS. 1, 2 and 3. However, in the present embodiment, the image sensor here has more vertical pixels than the 4 × 3 pixels shown in FIG. Here, in consideration of the TV rate, one field period (Field) is set to 1/60 second.
EX (1) is a P signal provided to each pixel connected to the transfer signal line 74 (1) to the reset signal line 76 (1) in FIG.
The exposure period of the D line group is shown. The transfer signal line SG74 for other signals to the column selection transistor 77 conforms to the symbol in FIG.

First, when reading out the photoelectric charges in the first row of the image pickup device, the line group of the PD 70 is exposed for (1 / 60-1 / 2000) seconds by exposure of EX (1), and T1
The FD is reset by the reset signal line SG76 (1) in the middle, and during the active period of the transfer signal line SG74 (1), the photoelectric charge is transferred from the PD 70 to the amplifying MOS transistor 8
3 is transferred to the FD of the gate. After that, the transfer signal line S
G74 (1) enters the disable period, and the transfer gate TX is turned off. After that, the selection signal line SG75 is turned on, the data is read out to the readout line 79, accumulated in the capacitor 85, and the column selection transistor 77 is turned on and the gate SG77 is turned on.
N, and outputs a video signal to the signal output line 78.

Next, the PD line group enters an exposure period of 1/2000 second. Then, after the end of the exposure period of 1/2000 second, the transfer signal line SG74 (1) to the column selection transistor 77 (1) are again controlled in the above sequence, and the photocharge by the exposure of 1/2000 second is transferred from the PD 70. The data is transferred to the FD (T32). O of transfer gate SG74
After the FF, exposure is performed for (1 / 60-1 / 2000) seconds, and this operation is repeated in the line.

Similarly, when reading out the photoelectric charges in the second row of the image sensor, the PD line group provided for each pixel connected to SG74 (2) to SG76 (2) is (1/60)
The cyclic control is performed from the exposure for −1/2000) seconds to reading of the imaging data to the FD (T3), and from the exposure for 1/2000 seconds to reading of the imaging data to the FD (T34).

Here, the period T2, whose timing is not shown, is a period during which the imaging data of the line whose exposure has been started 1/2000 seconds ago is read out to the FD, and T4, T32
Is a similar period. That is, (1 / 60-1 / 20
The reading of the imaging data from the exposure for 00) seconds to the FD and the reading of the imaging data from the exposure for 1/2000 seconds to the FD are alternately repeated.

The SG 77 amplifies the image data stored in the FD in the source follower 83 and outputs the selected signal
While 5 is active, the capacitors 85 (1) to 85 (4)
Column selection MOS transistor 7
This signal is used to activate the gates of the MOS transistors 7 (1) to 77 (4) by the horizontal drive unit 73 and output image data to the signal output line 78. In the case of the present embodiment, the output period of this signal is set so that the output period (T1 + T2) for two exposures is shorter than the (field period / number of scanning lines) period.

As described above, in this embodiment, (1/6) of EX (1) when reading out the photoelectric charges in the first row of the image sensor.
0-1 / 2000) seconds, and an exposure period of 1/2000 seconds of EX (2) for reading out the photocharges in the second row of the image sensor. , Two times of imaging data are alternately read out to the FD. Driving by a series of controls is performed by setting the output period of the video signal to one horizontal scanning period / number of exposures.
This is also effective in exposures of more than one time. In this embodiment, no special external storage device is required. According to this drive, SN (signal and noise) described later can be performed for each exposure. However, in this embodiment, the entire field period cannot be used as the longest exposure period. The driving means in which the entire field rate period can be used as the longest exposure period will be described in the third embodiment.

[Second Embodiment] In this embodiment, the cell amplifier 71 used in FIG. 2 is configured as shown in FIG.

The block diagram of the configuration of the imaging apparatus used in this embodiment is the same as that of FIG. 1 described in the first embodiment, and duplicate description will be omitted.

FIG. 2 shows an example of the structure of the amplification type solid-state image pickup device 33, which is the same as the image pickup device described in the first embodiment, and duplicate description will be omitted. Here, the imaging cell / amplifier 71 has a configuration as shown in a dotted frame 71 in FIG.

In FIG. 6, the charge accumulated in the PD 70 is accumulated in the FD having the gate of the source follower amplification type MOS transistor 83 in a floating structure, and the voltage amplified when the line selection MOS transistor 82 is ON. Is output to the read line 79. Also, reset M
The OS transistor 80 is a MOS transistor for resetting the FD. Note that the gates of these transistors are connected to a selection line 75 and an FD reset line 76, respectively. FIG. 2 shows the charge transfer line 7.
4 are shown, but are not used in the present embodiment.

In FIG. 2, the image pickup device 71 shown in FIG.
According to the circuit diagram of FIG. 7, the electric charge accumulated in the PD 70 is accumulated in the FD, and is supplied to the source follower 83 via the transistor 82 selected by the selection signal line 75 from the vertical drive unit 72.
, And read out to the readout line 79, and stored in the capacitor 85. Subsequently, a column selection signal is applied from the horizontal drive unit 73 to the column selection MOS transistors 77 (1) to 77 (4), and a video signal is output to the signal output line 78. At the start of the next exposure, the FD is reset by the reset signal line 76.

In the case of such a pixel structure, exposure is performed for a different period from the time when the FD is reset.

FIG. 7 is a timing chart when the image pickup driving of the present invention is performed using the image pickup system shown in FIGS. 1, 2 and 6. However, in this embodiment, FIG. 2 has more vertical pixels, not shown. Here, in consideration of the TV rate, one field period Field is set to 1/60 second. EX (1) is the selection SG75 of FIG.
(1) to Reset The exposure periods of the PD line group provided for each pixel connected to the SG (1) are shown. The other signal selections SG75 to SG77 are based on the symbols in FIG.

First, when reading out the first row of the image sensor, the PD line group is changed to (1/1) by the exposure of EX (1).
60-1 / 2000) second, and the charge of the PD 70 is charged by the FD of the gate of the source follower 83 during this exposure period.
Go to Then, the SG 75 (1) becomes active, and the imaging data is transferred from the readout line 79 to the capacitor 85 (1).
Is accumulated in Thereafter, the SG76 (1) signal becomes active, the FD is reset, and the next exposure is performed.

Next, the PD line group enters an exposure period of 1/2000 second. Then, after the end of the exposure period of 1/2000 second, SG75 (1) to SG77 (1) are controlled again in the above sequence, and the imaging data by the exposure of 1/2000 second is read out from the FD to the readout line 79. ,
It is stored in the capacity (1) (T32). After this, the FD returns to S
It is reset by the signal G76 (1) and again (1 / 60-1)
/ 2000) seconds, and this operation is repeated in the line.

Similarly, at the time of reading out the second row of the image sensor, the PD line group provided for each pixel connected to the selected SGs 75 (2) to SG76 (2) is shown as EX (2). As described above, after exposure for (1 / 60-1 / 2000) seconds, reading of image data from the FD (T3), and 1
After the exposure for / 2000 seconds, cyclic control is performed from FD to reading of image data (T34).

Here, the period T2, whose timing is not shown, is a period for reading out the imaging data of the line whose exposure has been started 1/2000 seconds ago from the FD, and T4 and T3.
3 is the same period. That is, (1 / 60-1 / 2)
The reading of the imaging data to the FD from the exposure for 000) seconds and the reading of the imaging data to the FD from the exposure for 1/2000 seconds are alternately repeated.

The read SG 77 is configured such that the image pickup data accumulated by the FD is amplified by the source follower 83, and the capacitances 85 (1) to 85 (8) are output while the selection signal line 75 is active.
The voltage stored in the capacitance of 5 (4) is applied to column selection 77 (1).
77 (4) are signals that make the gates of the MOS transistors selected and activated by the horizontal drive unit 73 and output image data to the signal output line 78. In the case of this embodiment,
The output period of this signal is the output period (T1 +
T2) is set to be shorter than the (field period / number of scanning lines) period.

As described above, in this embodiment, EX (1)
(1 / 60-1 / 2000) second exposure and EX (2) 1/2000 second exposure period are overlapped. Two image data are alternately taken by the FD using the validity of the two-dimensional address. Is being read to Driving by a series of controls is effective in three or more exposures by setting the video signal output period to one horizontal scanning period / number of exposures. In this embodiment, no special external storage device is required. According to this drive, noise cancellation can be performed for each exposure. However, in this embodiment,
The entire field period cannot be used as the longest exposure period. The driving means in which the entire field rate period can be used as the longest exposure period will be described in the fourth embodiment.

[Third Embodiment] In the first embodiment,
1/60 second of the field period is (1 / 60-1 / 200
0) second and 1/2000 second exposure period.

However, in the present embodiment, the exposure of 1/2000 sec. And 1/60 sec.
That is, a driving unit that can set the longest exposure period = field period is shown.

In this embodiment, the image pickup apparatus shown in FIG. 1 described above, the structure of each amplifying solid-state image pickup device 33 shown in FIG. 2, and each image pickup device shown in FIG. 3 are used. Is omitted.

Here, the electric charge accumulated in the PD 70 is transferred from the vertical drive unit 72 to the FD reset by the reset signal line 76 through the transfer gate 81 turned on by the transfer signal line 74, and the selection signal line 75. The signal is amplified by the source follower 83 via the selection MOS transistor 82 selected by the above, read out to the readout line 79, and stored in the capacitor 85. Subsequently, a column selection signal is applied from the horizontal drive unit 73 to the column selection transistors 77 (1) to 77 (4), and a time-series video signal is output to the signal output line 78 from the photocharge of each image sensor.

Whether the second exposure can be performed by analyzing the operation of each pixel will be described below. In FIG. 4A, the reset / MOS transistor 80 is turned on to reset the FD. After that, the FD reset is released by turning off the reset MOS transistor 80. PD during the first exposure period
The photo charge 90 accumulated by 70 is transferred to the gate FD of the source follower type amplification MOS transistor 83 by turning on the charge transfer transistor 81. Thereafter, the charge transfer MOS transistor is turned off. Subsequently, exposure for a second period is performed. Then, by turning on the charge transfer MOS transistor 81 without resetting the FD, the photocharge accumulated in the previous second period in the FD is added to the photocharge accumulated in the first period. Thereafter, the charge transfer transistor 81 is turned off. At this point, the PD 70 is ready for the next second exposure. The charge stored in the FD is read to the read line 79 by the source follower function of the transistor 83 and the ON state of the line selection transistor 82.

Subsequently, before the second exposure period is completed, F
D is reset. As shown in FIG. 4B, this operation first turns on the FD reset transistor 80.
And reset the FD. Thereafter, turning off the reset transistor 80 completes the reset of the FD.

FIG. 8 is a timing chart when the image pickup driving of the present invention is performed using the image pickup system shown in FIGS. 1, 2 and 3 described above. However, in this embodiment, FIG.
It has more vertical pixels not shown. Where T
Considering the V rate, one field period (Field) is 1 /
It is set to 60 seconds. EX (1) corresponds to 74 in FIG.
The exposure period of the PD line group provided for each pixel connected to (1) to (1) is shown. Other signals SG74
2 to 77 are based on the symbols in FIG.

First, by the exposure of EX (1), the PD line group is exposed to (1 / 60-1) after exposure for 1/2000 seconds.
/ 2000) seconds, and during the active period of SG74 (1) during T1, the photo charge is 1
The exposure charge of / 2000 seconds is transferred to the gate FD of the source follower 83 that has not been reset by SG76 (1). Thereafter, SG74 (1) enters a disable period, and the transfer gate is turned off. As a result, the FD has $ 1/2000 + (1 / 60-1 / 200)
0) Exposure charge for｝ = 1/60 second is stored. This charge is amplified and transferred to the external capacitors 85 (1) to 85 (4) while the SG 75 (1) is active.

Next, the PD line group enters an exposure period of 1/2000 second. Then, after the end of the exposure period of 1/2000 second, SG76 (1) is disabled from active, that is, the FD is reset, and the photocharge by the exposure of 1/2000 second is transferred from the PD to the FD (T3).
2). After the transfer gate is turned off, (1 / 60-1 / 200
An exposure is performed for 0) seconds, and this operation is repeated in the line. The exposure charge for 1/2000 second is SG75.
While (2) is active, external capacitances 85 (1) to 85 (1) to 85
It is amplified and transferred to (4).

Similarly, the PD line group provided for each pixel connected to 74 (2) to 76 (2) is (1/60)
The reading of the photocharge from the FD that has not been reset from the exposure for 1 second (T3), and the reading of the imaging data from the exposure for 1/2000 second to the FD that has been reset (T3)
It is cyclically controlled to 4).

Here, the period T2, whose timing is not shown, is a period for reading out the imaging data of the line whose exposure has been started 1/2000 seconds ago to the FD, and T4, T33.
Is a similar period. That is, (1 / 60-1 / 20
The reading of the imaging data from the exposure for 00) seconds to the FD and the reading of the imaging data from the exposure for 1/2000 seconds to the FD are alternately repeated.

The SG 77 outputs the voltage 77 (1) stored in the capacitors 85 (1) to 85 (4) while the image data stored in the FD is amplified by the source follower 83 and the signal line 75 is active. ) To 77 (4) are signals for selectively activating the gates of the MOS transistors from the horizontal drive unit 73 and outputting image data to the signal output line 78. In the case of the present embodiment, the output period of this signal is such that the output period (T1 + T2) for two exposures is (field period /
It is set to be shorter than the (number of scanning lines) period.

As described above, in this embodiment, the entire period of the field rate can be used as the longest exposure period. In addition,
The two exposures are overlapped by means of adding the charge generated by exposure for 1/60 seconds of EX (1) and the charge generated by exposure for 1/2000 seconds by FD, and also utilizes the validity of a two-dimensional address. Then, two times of imaging data are alternately read out to the FD. Driving by a series of controls is effective in three or more exposures by setting the video signal output period to one horizontal scanning period / number of exposures. In this embodiment, no special external storage device is required.

[Fourth Embodiment] In the second embodiment, the 1/60 second field period is set to (1 / 60-1 /
2000) seconds and an exposure period of 1/2000 seconds.

However, in the present embodiment, the cell amplifier 71 having the structure shown in FIG.
In contrast, a driving means in which exposure for 1/2000 seconds and 1/60 seconds, that is, field period = longest exposure period is shown.

FIGS. 1, 2 and 6 have the same configuration as that described in the second embodiment, and a duplicate description will be omitted. Although FIG. 2 shows the charge transfer line 74, it is not used in the present embodiment.

Here, the electric charge accumulated in the PD 70 is F
D, is amplified by the source follower 83 via the transistor 82 selected by the selection signal line 75 from the vertical drive unit 72, read out to the readout line 79, and
5 is stored. Subsequently, a column selection signal is applied from the horizontal driving unit 73 to the column selection transistors 77 (1) to 77 (4), and a video signal is output to the signal output line 78. In normal driving, the signal line 76 is used to start the next exposure.
The FD is reset. However, in the present embodiment, in order to effectively use the field period, a unit that shifts to exposure in the next period without resetting the FD is also used.

FIG. 7 is a timing chart when the image pickup driving of the present invention is performed using the image pickup system shown in FIGS. 1, 2 and 6. However, in this embodiment, FIG. 2 has more vertical pixels, not shown.

Here, as shown in FIG. 9, a specific exposure time corresponding to FIG. 7 is shown. Considering the TV rate, the one-field period Field is set to 1/60 second. EX (1) corresponds to 75 (1) to 76 (1) in FIG.
Shows the exposure period of the PD line group provided for each pixel connected to the pixel line. The other signals SG75 to SG77 conform to the symbols in FIG. FIG. 9 can be referred to according to the case shown in FIG.

First, the PD line group is exposed for 1/2000 seconds by the exposure of EX (1), and then (1/1).
Exposure for 60-1 / 2000) seconds, and the generated charges of the PD 70 are transferred to the FD provided on the gate 83 during this exposure period. Thereafter, the SG 75 (1) becomes active, and the photocharge of the FD is transferred to the external capacitance 85 (1) via 83.
To 85 (4). At this time, as described later, the previous 1/2000 second exposure charge is not reset on the FD, and as a result, the
The exposure charge for 0+ (1 / 60-1 / 2000)｝ = 1/60 seconds is read out this time. Then SG76
(1) The signal becomes active, the FD is reset,
The next 1/2000 second exposure is started. And 1 /
After the end of the 2000 second exposure period, the SG 75 (1) is disabled from active and the photocharge of the FD is transferred to the external capacitors 85 (1) to 85 via the source follower 83.
It is amplified and transferred to (4). As a result, image data obtained by 1/2000 second exposure is read (T32). F
D is not reset and again (1 / 60-1 / 2000)
Exposure is made for a second, and this operation is repeated in the line.

Similarly, select gates 75 (2) to 75 (76)
As shown in EX (2), the PD line group provided for each pixel connected to (2) reads out image data from the FD after exposure for (1/60) seconds (T3), and then returns to F
After resetting D and exposing for 1/2000 seconds, F
A cyclic control is performed from D to reading of the imaging data (T34).

Here, the period T2, whose timing is not shown, is a period for reading out the imaging data of the line whose exposure has been started 1/2000 seconds ago from the FD, and T4 and T3.
3 is the same period. That is, reading of the imaging data from the exposure for 1/60 second to the FD and reading of the imaging data from the exposure for 1/2000 second to the FD are alternately repeated.

The SG 77 amplifies the image data stored in the FD in the source follower 83 and converts the voltage stored in the capacitors 85 (1) to 85 (4) while the signal line 75 is active to 77 (4). These signals are for making the gates of the MOS transistors 1) to 77 (4) selectively active by the horizontal drive unit 73 and outputting imaging data to the signal output line 78. In the case of the present embodiment, the output period of this video signal is
The output period (T1 + T2) for two exposures is set to be shorter than the (field period / number of scanning lines) period.

As described above, in this embodiment, the entire field rate period can be used as the longest exposure period. In addition,
The two exposures are overlapped by means of adding in the FD the charge generated by exposure for 1/60 seconds of EX (1) and the charge generated by exposure for 1/2000 seconds, and the two-dimensional address Utilizing the validity, two times of imaging data are alternately read out to the FD. It should be noted that the drive by a series of controls is effective in three or more exposures by setting the video signal output period to one horizontal scanning period / number of exposures.
In this embodiment, no special external storage device is required.

[Fifth Embodiment] In this embodiment, in addition to FIG. 1 of the first and second embodiments, the imaging data control including "a storage device having less than one field image data" shown in FIG. It has a part 1. The imaging data control unit 1
Will be described in more detail with reference to FIG.

Here, in FIG.
Is a memory for storing digitized imaging data from the A / D converter 5. The memory stores the image data read at T1 in FIG. 5, and then stores the image data read at T3.

Accordingly, (1/6)
Only the imaging data of (0-1 / 2000) second exposure is stored. Further, the memory groups 17 to 21 are stored in FIFO (Fi
rstIn First Out), and the imaging data stored in 17 is changed from 18 to 18 every time new imaging data is input.
It is shifted in the order of 19 → 20 → 21.

Reference numeral 23 denotes a threshold voltage setting unit. In the present embodiment, the FD (accumulated charge amount-margin amount) in FIG.
Are voltage-converted and amplified, and the voltage at which the voltage is output from the source follower 83 is stored as a set value. Further, the image data stored in the memory 21 and the value of 23 are compared by the comparison / replacement unit 22. If the data in the memory 21 is larger, the exposure is performed in 1/2000 seconds input with a time-series delay. Is replaced with the captured image data. (1 / 60-
1/2000) image data exposed in seconds and 1/200
The time-series relationship of the imaging data exposed in 0 seconds is approximately [(1
/ 2000) / {(1/60) / 480}] line 1
/ 2000 seconds of imaging data is input with a delay (however,
2 shows an example in which the image pickup apparatus shown in FIG. 2 is driven at the timing shown in FIG. 5 and is set to 1/60 second in one frame period, 480 scanning lines, and non-interlace. However, in the present embodiment, for the sake of simplicity, it is assumed that the imaging data of 1/2000 second is input with the delay amount of moving the imaging data of 1/60 second to the memory 21 from the input of the imaging data of 1/60 second. It is drawn.

Next, "1" is stored in the flag memory 16 by the comparison / replacement unit 22 when the image data in the memory 21 has been replaced, and "0" otherwise. This flag is output by the flag output unit 26, and the imaging data is output by the output timing generation unit 25.
Thereby, both are supplied to the signal processing unit 7 in synchronization with each other.
The imaging data control unit 1 has a portion 27 for storing and outputting a magnification ratio between the imaging data exposed in the first period and the imaging data exposed in the second period. By referencing, it is possible to match the scale of the image data exposed in the second period to the scale of the data exposed in the first period. Similarly, this example can be applied to the third and fourth embodiments.

[Sixth Embodiment] In this embodiment, FIG.
As shown in FIG. 2, the detection means and the flag setting means of the imaging data control unit 1 shown in FIGS. 10 and 11 used in the second embodiment are different, and newly output from the A / D conversion unit 5. An upper bit detection unit 28 that detects specific bits or more of the imaging data is provided. In the present embodiment, the value of [accumulated charge amount−margin amount] of the FD in FIG.
The higher-order bits that have undergone the voltage conversion amplification and are substantially equal to or more than the values output when output from the source follower 83 are detected.

With the above-described means, the speed of the detection means is increased, and the flag detection data replacement section 29 provided in the image data control section 1 is simplified and speeded up as compared with the comparison and replacement section 22.

Further, like the imaging data control section 1 shown in FIG. 12, the memories 17 to 21 are memories for storing digitized imaging data from the A / D conversion section 5.
The memory stores the image data read at T1 in FIG. 5, and then stores the image data read at T3. Therefore, these memory areas have (1/60
Only the imaging data of the (1/2000) second exposure is stored. Further, the memory groups 17 to 21 have a FIFO structure, and the imaging data stored in the memory 17 is changed every time new imaging data is input from the memory 18 → 19 → 20 →
It is shifted to 21 and moved.

Also, 12 to 16 are memories 17 to 21
And a flag storage unit paired with the upper bit detection unit 2
In step 8, "1" is stored when "1" of a bit equal to or larger than the specified bit is detected, and "0" is stored in the case of other imaging data values. Each time a new flag is input, the flag storage unit is paired with the image data and stored in the flag storage unit 1.
It is shifted as 3 → 14 → 15 → 16 and moved.

The flag detection data replacement section 29 detects whether the flag storage section 16 is "1" or "0". If the flag storage section 16 is "1", the flag detection data replacement section 29 performs exposure in 1/2000 seconds input with a time series delay. Is replaced with the captured image data.

The flag of the flag storage unit 16 is supplied to the signal processing unit 7 by the flag output unit 26, and the imaging data is supplied to the signal processing unit 7 by the output timing generation unit 25. The imaging data control unit 1 has a portion 27 for storing and outputting a magnification ratio between the imaging data exposed in the first period and the imaging data exposed in the second period, and the signal processing unit 7 refers to the magnification. By doing so, it is possible to match the scale of the imaging data exposed in the second period to the scale of the data exposed in the first period. Similarly, this example can be applied to the third and fourth embodiments.

[Seventh Embodiment] FIG. 13A shows an S which can be applied to an image pickup apparatus constituted by a cell amplifier as shown in FIG.
-N means an example.

FIG. 13B is an operation timing chart of FIG. 13A, in which SG76 is an FD reset signal,
SG91 is an N transfer signal for transferring a noise component, SG74
Is a charge transfer signal, SG90 is an S transfer signal for transferring a signal component, and SG75 is a line pixel selection line.

In the operation of FIG. 13A, first, the reset signal of the SG 76 becomes active, and the FD provided at the gate of the source follower 83 shown in FIG. 3 is reset. The signal N at that time is transferred to the capacitor 87 during the active period of the SG 91, that is, during the ON period of the MOS transistor 89, via the source follower 83 by the SG 75 active. Next, the charge transfer pulse SG74 from PD to FD becomes active, and the S + N signal becomes F
D accumulates as electric charge. The S + N signal is supplied to the source follower 83 by the activation of the SG 75.
Is transferred to the capacitor 86 while the S transfer signal 90 is active, that is, while the MOS transistor 88 is ON. Thus, the S + N signal stored in the capacitor 86 and the N signal stored in the capacitor 87 are output by the differential amplifier 92 as {(S + N) -N} = S signal.

When this is applied to the first embodiment,
The timing chart is as shown in FIG.
Circuit, MOS transistor 77 and horizontal drive unit 73
If two sets of are provided, it is possible to execute SN with an exposure of (1 / 60-1 / 2000) seconds and an exposure of 1/2000 seconds. The same can be applied to the second embodiment.

[Eighth Embodiment] In FIG. 15A, the first of a group of imaging elements connected to a transfer signal line 74 (1), a selection signal line 75 (1), and a reset signal line 76 (1).
The PD line group in the row is exposed for a period of 1/60 second, and the next line of the image pickup device group connected to the transfer signal line 74 (2), the selection signal line 75 (2), and the reset signal line 76 (2). The second line of PD lines is exposed for a period of 1/2000 seconds. Similarly, a PD line group corresponding to the subsequent exposure period is set as a fixed exposure period. This means that, for example, an image sensor is divided into an odd line and an even line as an area sensor, and an odd line image sensor has a 1/60 second exposure period, and an even line image sensor has a 1/2000 second exposure period. Drive. Accordingly, when the longest exposure period is equal to the field period, and is shorter than other exposures such as 1/2000 second exposure, the exposure start point can be set freely, and a plurality of exposures can be performed within the field period. It becomes possible.

However, the resolution may be more important than the performance enhancement such as the dynamic range obtained by such different exposure. For example, there is a case where a still image is shot as a still image.

In this case, as shown in FIG. 15B, the PD line group connected to the transfer signal line 74 (1), the selection signal line 75 (1), the reset signal line 76 (1), and the next The PD line groups connected to the lines 74 (2), 75 (2) and 76 (2) are all subjected to the same exposure period, for example, 1/60 corresponding to one field for the exposure period of all the image sensors.
Switch for seconds.

By switching between the two driving means, for example, a dynamic range can be emphasized for a moving image and a resolution can be increased for a still image.

[0088]

The exposure period in the field can be lengthened by multiplexing exposures of different periods in the image pickup device of the image pickup apparatus. In addition, by using an amplification type solid-state imaging device, exposure accumulation can be repeated by the floating diffusion, and the exposure period can be further lengthened.

Further, by using a solid-state image sensor that outputs image data by designating a two-dimensional array, it is possible to reduce the storage capacity for a plurality of exposure data processes.

As a solid-state imaging device satisfying the above requirements, an amplification type solid-state imaging device is known. When this image sensor is used for a moving image such as a video, the dynamic range can be widened, and in the case of a still image such as a still camera, priority can be given to the resolution by selectively driving the exposure cells.

[Brief description of the drawings]

FIG. 1 is a block diagram of an imaging apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of an imaging device according to an embodiment of the present invention.

FIG. 3 is a circuit block diagram of an image sensor according to an embodiment of the present invention.

FIG. 4 is a read energy potential diagram of an image sensor according to an embodiment of the present invention.

FIG. 5 is a timing chart of the imaging device according to the embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of an imaging device according to an embodiment of the present invention.

FIG. 7 is a timing chart of the imaging device according to the embodiment of the present invention.

FIG. 8 is a timing chart of the imaging apparatus according to the embodiment of the present invention.

FIG. 9 is a timing chart of the imaging device according to the embodiment of the present invention.

FIG. 10 is a block diagram of an imaging apparatus according to an embodiment of the present invention.

FIG. 11 is a block diagram of an imaging data control unit for an imaging device according to an embodiment of the present invention.

FIG. 12 is a circuit configuration diagram of an imaging device according to an embodiment of the present invention.

FIG. 13 is a block diagram of an imaging data control unit for an imaging device according to an embodiment of the present invention, and a timing chart of the imaging device.

FIG. 14 is a timing chart of the imaging apparatus according to the embodiment of the present invention.

FIG. 15 is a circuit configuration diagram of an imaging device according to an embodiment of the present invention.

FIG. 16 is a circuit configuration diagram of an imaging device according to a conventional example.

FIG. 17 is a timing chart of an imaging device according to a conventional example.

[Explanation of symbols]

 Reference Signs List 1 imaging data control unit 5 A / D conversion unit 6 objective lens (imaging lens) 7 signal processing unit 12-16 flag memory 17-21 memory 22 comparison and replacement unit 23 threshold setting unit 25 output timing generation unit 26 flag output Unit 27 Relation magnification 28 Upper bit detection unit 29 Flag detection and replacement unit 33 Image sensor 38 Timing generator (TG) 39 Processing unit (CPU) 70 Photodiode (PD) 71 Image sensor 72 Vertical drive unit (vertical register) 73 Horizontal drive Section (horizontal register) 74 transfer signal line 75 selection signal line 76 reset signal line 77 column selection MOS transistor 78 video signal output line 79 readout line 80 reset MOS transistor 81 transfer MOS transistor 82 selection MOS transistor 83 source follower (amplification) OS transistor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4M118 AA02 AB01 BA10 BA14 CA02 DB01 DD04 DD09 DD12 FA06 FA33 FA38 FA50 5C024 AA01 CA15 CA17 GA01 GA31 HA08 HA09 HA14 HA18 HA23 HA24 JA04 JA11

Claims (20)

[Claims] 1. An imaging apparatus, wherein an exposure portion in a first period and an exposure portion in a second period are mixed in an imaging panel having a photoelectric conversion element. 2. A method according to claim 1, wherein the signal from the image data detecting means by the exposure in the first period and the signal from the image data detecting means by the exposure in the second period are interlaced in the imaging panel having the photoelectric conversion element. An imaging device, which is read. 3. An imaging apparatus, comprising: reading out image data obtained by exposure in a second period before completing exposure in a first period in an imaging panel having a photoelectric conversion element. 4. An image pickup device comprising: an image pickup device that photoelectrically converts a subject image and outputs a video signal according to a two-dimensional specification; and a circuit that electrically controls the image readout circuit to read out a video signal. Means for reading out image data obtained by exposing the obtained photoelectric conversion element in a first period and image data obtained by exposing the photoelectric conversion element in a second period different from the first period; An image pickup apparatus, wherein reading of image pickup data exposed during the first period from a conversion element is performed by interlaced scanning. 5. The imaging device according to claim 4, further comprising: a unit configured to detect that imaging data obtained by exposing the photoelectric conversion element during the first period is equal to or greater than a specified value, and An imaging apparatus, comprising: means for replacing image data exposed during a second period. 6. The imaging device according to claim 4, further comprising an analog memory or a digital memory for storing said first and second imaging data, wherein a first exposure period and a second exposure time are stored in said plurality of imaging elements. An imaging apparatus wherein a second exposure period progresses in a multiplexed manner. 7. The imaging apparatus according to claim 4, wherein short- and long-term exposure is performed between said first period and said second period. 8. The imaging apparatus according to claim 6, further comprising: means for providing an identifier at a storage location where data has been replaced by the first storage means. 9. The imaging device according to claim 4, wherein: the imaging data obtained by exposing the photoelectric conversion element during a first period;
An imaging apparatus, comprising: a third storage unit that stores a magnification related to imaging data obtained by exposing the photoelectric conversion element in a second period. 10. The imaging device according to claim 4, wherein
Means for detecting that image data obtained by exposing the photoelectric conversion element during a first period is equal to or greater than the saturated charge amount of the photoelectric conversion element; An imaging apparatus characterized by making a determination by comparing with: 11. The imaging device according to claim 10, wherein the means for detecting that the imaging data obtained by exposing the photoelectric conversion element in the first period is equal to or more than the saturation charge of the photoelectric conversion element is: An image pickup apparatus characterized in that the image data value exposed in the first period is determined based on upper bits of a digital value obtained by analog / digital conversion. 12. The imaging apparatus according to claim 10, wherein the number of times of exposing the photoelectric conversion element in different periods is three or more. 13. An imaging apparatus, wherein a photoelectric conversion element that exposes a photoelectric conversion element in a first period and a photoelectric conversion element that exposes a photoelectric conversion element in a second period are provided separately on the same substrate. . 14. The imaging apparatus according to claim 13, wherein in the imaging at a frame rate of (1/30) second or less, the separated photoelectric conversion elements are exposed for substantially the same exposure time. An imaging apparatus wherein the first period and the second period are substantially the same. 15. A plurality of two-dimensionally arranged photoelectric conversion elements, transfer of electric charges of the plurality of photoelectric conversion elements, resetting of the photoelectric conversion elements, and reading of a video signal by selecting the photoelectric conversion elements. In the imaging apparatus, one vertical scanning period is divided into a plurality of times, and an exposure unit that exposes the photoelectric conversion element for each of the plurality of times, and a signal charge stored in the photoelectric conversion element are independently selected and a video signal is selected. An image pickup apparatus, comprising: a reading unit that reads out an image. 16. An imaging panel having a photoelectric conversion element is divided, exposed in a first period, exposed in a second period different from the first period, and portions to be exposed are mixed. The driving method of the imaging device described above. 17. An imaging panel having a photoelectric conversion element is divided, image data obtained by exposure in a first period is detected, image data obtained by exposure in a second period is detected, and read by interlaced scanning. The driving method of the imaging device described above. 18. A method for driving an imaging device, comprising dividing an imaging panel having photoelectric conversion elements and reading out imaging data obtained by exposure in a second period before completing exposure in a first period. 19. An object image is photoelectrically converted to a video signal of 2
In a driving method of an imaging device including an imaging device that outputs by specifying a dimension and a circuit that electrically controls the imaging device to read out a video signal, the photoelectric conversion device used in the imaging device is exposed during a first period. Reading image data, reading image data obtained by exposing the photoelectric conversion element in a second period different from the first period, reading image data exposed in the first period from the photoelectric conversion element; A method for driving an image pickup apparatus, comprising: 20. A plurality of two-dimensionally arranged photoelectric conversion elements, transfer of electric charges of the plurality of photoelectric conversion elements, resetting of the photoelectric conversion elements, and reading of a video signal by selecting the photoelectric conversion elements. In the driving method of the image pickup apparatus, one vertical scanning period is divided into a plurality of times, the photoelectric conversion elements are exposed at each of the plurality of times, and signal charges stored in the photoelectric conversion elements are independently selected to form a video signal. And resetting the photoelectric conversion element.