JP2000299817A - Solid-state imaging device, driving method thereof, and camera system - Google Patents

Abstract

(57) [Problem] In an electronic still camera, in a monitoring mode, a driving method of thinning-out reading is adopted for the purpose of increasing a frame rate, so that noises in the same direction as vertical transfer of smear, dark current, etc. Ingredients matter. SOLUTION: A signal packet corresponding to each of the light receiving elements (pixels) 12 in one vertical pixel column and a packet sequence having at least one empty packet per one vertical pixel column are provided. In the CCD image pickup device provided with the vertical transfer unit 13 for transferring in the direction, the component of the empty packet is put on the P (preset) phase and outputted, and the signal output Vout of the CCD image pickup device in the subsequent signal processing system is D By taking the difference between the (data) phase component and the P phase component, noise components such as smears and dark currents that travel in the same direction as vertical transfer are suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device, a method of driving the same, and a camera system, and more particularly, to a solid-state imaging device capable of so-called thinning-out read driving in which signal charges are thinned out from each pixel and a driving method thereof. And a camera system using the same.

[0002]

2. Description of the Related Art As a problem in a solid-state imaging device, there are noise components such as smear and dark current. Here, smear is a noise component that is generated because light is directly mixed into the vertical transfer unit or an electric charge generated inside the semiconductor substrate is spread by diffusion and mixed into an adjacent pixel or the vertical transfer unit.
The dark current is a noise component generated irrespective of the amount of incident light, and its generation factors include a diffusion current from a semiconductor substrate, a current from a depletion layer on the substrate surface, and a current generated from a surface state at an interface. No.

[0003] The smear and dark current are noise components riding in the same direction as the vertical transfer. Depending on the driving method of the solid-state imaging device, the noise in the vertical direction may be promoted, and in that case, there is a particular problem. As an example of a driving method that promotes noise, a CCD (Charge Coupled Device) for an electronic still camera for capturing a still image is read out by thinning out signal charges of each pixel in a vertical direction when confirming an imaging screen. (Hereinafter, referred to as “thinning-out reading”), a driving method for performing a driving process for improving a frame rate can be given.

Here, a CCD image pickup device for an electronic still camera for capturing a still image will be described. The CCD image pickup device for an electronic still camera employs, for example, all-pixel read driving. In the schematic diagram of FIG. 11, a white circle (白) indicates a noise component on the vertical transfer unit 101,
Black circles (•) indicate signal components including a noise component transferred during one horizontal blanking period.

In the all-pixel read driving, as shown in FIG. 11A, signal charges (indicated by black squares in the figure) of all pixels are simultaneously read to the vertical transfer unit 101 at the same time, and In the transfer unit 101, the signals are independently transferred in the vertical direction without mixing, and the signal charges are further transferred to the horizontal transfer unit 1
02 is transferred in the horizontal direction and read out via the charge detection unit 103.

In the all-pixel read driving (A), the number of transfer pixels in one vertical transfer unit per horizontal blanking period is one. The number of signal pixels output at one time is one, and the amount of noise output at one time is for one vertical transfer unit (the amount of noise for one packet). In this case, it is assumed that the mechanical shutter is not used even in all-pixel reading.

On the other hand, in the thinning-out read driving, FIG.
As shown in (B), for example, in the case of thinning out every other pixel in the vertical direction, odd rows (1, 3, 5,.
..) Are read out to the vertical transfer unit 101 only. At this time, an empty packet exists in the vertical transfer unit 101. Then, the signal packet and the empty packet are transferred in pairs in the vertical direction, and the charges of the two packets are mixed in the horizontal transfer unit 102 and transferred in the horizontal direction, and are read out via the charge detection unit 103. ing.

In the thinning-out reading drive (B), the number of transfer pixels in one vertical transfer unit per horizontal blanking period is two. The number of signal pixels output at one time is one, and the amount of noise output at one time is for two vertical transfer units (the amount of noise for two packets).

As is apparent from the above description of operation, noise is promoted by the thinning-out read driving method (B) because there are empty packets from which signal charges are not read out, and the empty packets are also vertically transferred. Since the noise component on the unit 101 is accumulated, the horizontal transfer unit 102 performs mixing between two vertical pixels (upper and lower two packets), so that a noise component for two packets is generated for a signal component for one pixel. This is because the S / N ratio is doubled (6 dB).

[0010]

As a practical method of using an electronic still camera, a device that closes a mechanical shutter when capturing a still image does not cause noise components such as smears. When the imaging screen is checked (monitored), a thinning-out read driving method is adopted for the purpose of increasing the frame rate, and therefore, a noise component that runs in the same direction as vertical transfer of smear, dark current, or the like becomes a problem. .

As a method of removing a noise component riding in the same direction as the vertical transfer, a method of canceling the noise component using pixel information of a light-shielded area (optical black area) of the same vertical transfer unit is also known. Have been. However,
In the case of this method, it is necessary to prepare a frame memory outside the CCD image pickup device and perform signal processing using this frame memory, so that the cost increases accordingly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide the same direction as vertical transfer of smear and dark current without adding a special circuit to a signal processing system. It is an object of the present invention to provide a solid-state imaging device capable of removing a noise component that rides on a camera, a driving method thereof, and a camera system.

[0013]

In order to achieve the above object, according to the present invention, a plurality of pixels arranged in a matrix, a signal packet corresponding to each pixel of one vertical pixel column, and one vertical pixel are provided. A solid-state imaging device comprising a packet sequence having at least one empty packet per column and having a plurality of vertical transfer units for vertically transferring signal charges read from a plurality of pixels. Transfer in the horizontal direction without mixing
The horizontally transferred charges are sequentially converted into electric signals, the components of the empty packets are put on the preset phase, and the components of the signal packets are put on the data phase and output. Then, in a subsequent signal processing system, the difference between the data phase component and the preset phase component of the output signal of the solid-state imaging device is calculated.

In the above configuration, noise components such as smear and dark current are generated in the empty packet by the same noise amount as in the signal packet of the same vertical pixel column. By outputting the noise component of the empty packet on the preset phase of the output waveform of the solid-state imaging device, the noise component can be extracted independently of the signal component of the data phase. Therefore, the noise component included in the signal component can be canceled by calculating the difference between the data phase component and the preset phase component in the subsequent signal processing system.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating a solid-state imaging device according to a first embodiment of the present invention. Here, for example, in the case of an all-pixel read-out driving CCD image sensor, in addition to the all-pixel read mode, a case where a thinning-out readout mode in which pixel information is thinned out at every other pixel in the vertical direction, for example, may be taken. It shall be.

In FIG. 1, an image pickup section (image pickup area) 11
Are a plurality of light receiving elements (pixels) 12 such as photodiodes, which are arranged in a matrix on a semiconductor substrate, convert incident light into signal charges having a charge amount corresponding to the light amount, and accumulate the signal charges.
And a plurality of vertical transfer units 13 provided for each vertical column of the plurality of light receiving elements 12 along the arrangement direction.

The plurality of vertical transfer units 13 include:
1 and a set (packet sequence) of empty packets arranged one by one in front of the signal packets in the vertical transfer direction, and three packets are provided on the transfer channel of each packet. One transfer electrode (not shown) is arranged in the transfer direction. Here, a packet refers to a unit that handles one signal component or noise component on a signal charge transfer path. Then, the vertical transfer section 13 is transfer-driven by, for example, three-phase vertical transfer pulses Vφ1, Vφ2, Vφ3.

That is, during the horizontal blanking period, the vertical transfer section 13 transfers signal charges for one row (one line) line by line in accordance with the three-phase vertical transfer pulses Vφ1, Vφ2, and Vφ3 (hereinafter, referred to as “line”). This is called a line shift). Here, since part of the transfer electrode of the vertical transfer unit 13 also serves as the readout gate electrode,
One of the vertical transfer pulses Vφ1, Vφ2, and Vφ3 takes a ternary level of a low level, an intermediate level, and a high level, and the third high-level pulse is a read pulse.

However, the three-phase vertical transfer pulses Vφ1, V
The way of applying φ2 and Vφ3 to each packet is different in the thinning-out reading mode from that in the all-pixel reading mode. In other words, for pixels from which signal charge readout is thinned,
As a matter of course, no read pulse is given. In the vertical transfer unit 13, the line shift is performed once in the horizontal blanking period in the all-pixel reading mode, whereas the line shift is performed twice in the horizontal blanking period in the thinning-out read driving every other pixel. Will be

A horizontal transfer unit 14 is arranged below the image pickup unit 11 in the drawing, adjacent to the ends of the plurality of vertical transfer units 13 in the transfer direction. In the thinning-out reading mode, the horizontal transfer unit 14 needs to transfer a signal component and a noise component as a pair. Therefore, the arrangement (packet sequence) of twice the number of pixels in the horizontal direction (double density) is performed. ). The transfer is driven by horizontal transfer pulses Hφ1 and Hφ2 having phases opposite to each other. The horizontal transfer pulses Hφ1 and Hφ2 are set at twice the normal frequency since the horizontal transfer unit 14 has a double density.

At the end of the horizontal transfer section 14 on the transfer destination side, a signal charge transferred by the horizontal transfer section 14 is detected, converted to a signal voltage and output, for example, a floating diffusion amplifier configuration. Charge detection unit 1
5 are arranged. The charge detection unit 15 is provided with an FD provided adjacent to the final output gate 16 of the horizontal transfer unit 14.
(Floating diffusion) section 17, RD (reset drain) section 18 for sweeping charge, and FD section 1
And an RG (reset gate) unit 19 for discharging the electric charge of No. 7 to the RD unit 18.

In the charge detecting section 15, the RD section 18
Is supplied with a predetermined drain voltage Vrd. Further, a reset gate pulse RGφ having, for example, the same cycle as the horizontal transfer pulses Hφ1 and Hφ2 is applied to the RG unit 19. From the FD unit 17, a signal output Vout obtained by converting the signal charge into a signal voltage is derived. Note that the vertical transfer pulses Vφ1 to Vφ3, the horizontal transfer pulse H
Various timing signals including φ1, Hφ2 and reset gate pulse RGφ are generated by the timing generation circuit 20.

FIG. 2 shows horizontal transfer pulses Hφ1, Hφ2,
The timing relationship between the reset gate pulse RGφ and the signal output Vout is shown. In the waveform of the signal output Vout, the P-phase is a preset section, the D-phase is a data section, and the horizontal transfer section 14 has a double-density configuration with two packets as one unit. The information of the packet on the rear side is output to the P phase as the D phase.

Next, the operation of each driving mode of the CCD image pickup device of the above-structured all-pixel read driving method will be described.
This will be described with reference to the schematic diagrams of FIGS. In each of the schematic diagrams of FIGS. 3 and 4, a white circle (○) represents a noise component on the vertical transfer unit 13 and a black circle (●) represents noise transferred in one horizontal blanking period. The signal components including the components are shown.

First, when the all-pixel reading mode is set by the mode switching signal, the timing generation circuit 20
Outputs vertical transfer pulses Vφ1 to Vφ3 at a timing corresponding to the mode. As a result, in the schematic diagram of FIG. 3, the signal charges of all the pixels (indicated by black squares in the figure) are simultaneously read out to the vertical transfer unit 13 at the same time (A).

Subsequently, before the line shift is performed in the vertical transfer section 13, the horizontal transfer section 14
Uses two packets as one unit, so that the horizontal transfer unit 14 previously shifts by one bit (one packet) in order to supply signal charges to the packet on the rear side in the horizontal transfer direction of this packet pair. , This is referred to as a 1-bit shift). Thereafter, the line shift is performed once within the horizontal blanking period. As a result, the signal charges for one line (one row) are shifted to the horizontal transfer unit 14 (B).

In this way, the signal charges for one line shifted from the vertical transfer unit 13 to the horizontal transfer unit 14 are transferred in the horizontal direction by the horizontal transfer pulses Hφ1 and Hφ2.
The charges are sequentially injected into the charge detection unit 15 in pixel units. In the charge detection section 15, a reset operation of discharging the residual charges of the FD section 17 to the RD 18 is performed by applying the reset gate pulse RGφ to the reset gate section 19 in the same cycle as the horizontal transfer pulses Hφ1 and Hφ2.

As a result, a signal output Vout having a waveform as shown in FIG. 2 is derived from the FD section 17. Note that, in the all-pixel read mode, as is apparent from the above-described operation description, the vertical transfer unit 13
No information is given to them. Therefore, in the signal output Vout, no information is put on the P phase, the P phase is a reference for signal processing described later, and information on the signal component is put on the D phase.

On the other hand, when the thinning-out reading mode is set by the mode switching signal, the timing generation circuit 20
Outputs vertical transfer pulses Vφ1 to Vφ3 at a timing corresponding to the mode. Thus, in the schematic diagram of FIG. 4, for example, only signal charges (indicated by black squares in the drawing) of pixels in even-numbered rows (2, 4,... In the drawing) are read out to the vertical transfer unit 13 ( A).

Subsequently, in the vertical transfer section 13, the first line shift is performed within the horizontal blanking period. As a result, the charge of the noise component for one line is supplied from the vertical transfer unit 13 to the packet on the front side in the horizontal transfer direction of the packet pair of the horizontal transfer unit 14 (B). Subsequently, the horizontal transfer unit 14 performs a one-bit shift.

Next, in the vertical transfer section 13, a second line shift is performed within the same blanking period. Thereby, the charge of the signal component for one line is supplied from the vertical transfer unit 13 to the packet on the rear side in the horizontal transfer direction of the packet pair of the horizontal transfer unit 14 (C). As a result, on the horizontal transfer unit 14, the charge of the noise component is accumulated before the packet pair, and the charge of the signal component is accumulated behind the packet pair.

As described above, the charges of the noise component and the signal component shifted from the vertical transfer unit 13 to the horizontal transfer unit 14 by performing the line shift twice in the horizontal blanking period are paired in the horizontal direction. Transferred,
The charges are sequentially injected into the charge detection unit 15. In the charge detector 15, a reset operation is performed by a reset gate pulse RGφ having the same cycle as the horizontal transfer pulses Hφ1 and Hφ2. As a result, in the signal output Vout having a waveform as shown in FIG. , And the information of the signal component is carried on the D phase.

In the charge detecting section 15, the reset operation is performed in the same cycle as the transfer cycle of the horizontal transfer section 14, so that the reset operation is also performed between the P phase and the D phase. As a result, a noise component for one packet is on the P phase, and a signal component and a noise component for one packet are on the D phase.

As described above, in the CCD image pickup device of the all-pixel reading drive system, in the thinning-out reading mode, each charge of the signal packet and the empty packet is transferred as a set (in this example, a pair) and horizontally transferred. The electric charges are sequentially converted into electric signals, and the noise component of the empty packet is put on the P phase, and the signal component of the signal packet is put on the D phase and output. The noise information of the address can be obtained in combination with the pixel information.

Therefore, in the subsequent signal processing system,
By performing the process of calculating the difference between the D-phase signal component and the P-phase noise component, the noise component included in the signal component can be canceled. Here, the noise component of the empty packet refers to noise that is transmitted in the same direction as vertical transfer of smear, dark current, and the like.

FIG. 5 is a block diagram showing an example of the configuration of the camera system according to the present invention. This camera system captures incident light (image light) from a subject (not shown) and a CCD image pickup device 21 as an image pickup device.
A lens 22 that forms an image on an imaging surface of the D imaging element 21;
A signal processing circuit 23 for performing various signal processing on an output signal of the CCD image sensor 21; a mode setting unit 24 for setting an imaging mode; and a CCD image sensor according to the imaging mode set by the mode setting unit 24 CCD driving 21
It has a configuration having a drive circuit 25.

In this camera system, as the CCD image pickup device 21, the CCD image pickup device according to the above-described first embodiment, that is, the CCD image pickup device having a configuration capable of selectively performing the all-pixel reading mode and the thinning-out reading mode is used. . Further, the mode setting unit 24 can selectively set, as an imaging mode, a normal imaging mode for capturing a still image, for example, and a monitoring mode for checking an imaging screen on an attached liquid crystal television, for example.

On the other hand, the CCD drive circuit 25 has a configuration having the timing generation circuit 20 in FIG.
When the normal imaging mode is set by the mode setting unit 24, the CCD image sensor 21 is driven by the all-pixel reading drive, and when the monitoring mode is set by the mode setting unit 24, the thinning-out reading drive is performed to increase the frame rate. To drive the CCD imaging device 21. Each drive of all-pixel reading and thinning-out reading is performed according to the above-described operation procedure.

The signal processing circuit 23 includes the CCD image pickup device 2
1 that removes noise components contained in the output signal of the CDS (C
orrelated Double Sampling (correlated double sampling) circuit is provided. FIG. 6 shows an example of the circuit configuration of the CDS circuit. In the waveform of the signal output Vout in FIG. 2, the sampling pulse φSHP generated at the P-phase timing and the sampling pulse φSHD generated at the D-phase timing are applied to the CDS circuit.

As shown in FIG. 6, the CDS circuit 30 includes a sample / hold (S / H) circuit 31 for sampling the output (CCD output) of the CCD image pickup device 21 with a sampling pulse φSHP. A sample and hold circuit 32 for sampling the output with a sampling pulse φSHD;
It comprises a sample-and-hold circuit 33 for sampling one CCD output with a sampling pulse φSHD, and a differential amplifier 34 having each output of the sample-and-hold circuits 32, 33 as two inputs.

In the CDS circuit 30 having the above configuration, C
P phase of CCD output of CD image sensor 21 (preset part)
And the D phase (data section)
Sample and hold circuit 31 in synchronization with SHP and φSHD
33, and the difference is obtained by a differential amplifier 34. Here, the reason why the P phase is sampled again with the sampling pulse φSHD is to match the phase with the D phase.

As described above, in the signal processing circuit 23,
In the CDS circuit 30, P of the CCD output of the CCD image sensor 21 is output.
By performing the process of calculating the difference between the phase and the D phase, as shown in FIG. 7, even if, for example, low-frequency noise is added to the CCD output, the noise component is canceled by calculating the difference based on the P phase. be able to.

When the thinning-out reading drive is performed on the CCD image pickup device 21 when the monitoring mode is set, as described above, the noise component of the empty packet is in the P phase, and the signal component of the signal packet is Since a CCD output in which the + noise component is on the D phase is obtained, the noise component can be canceled by calculating the difference between the P phase and the D phase in the CDS circuit 30. Thereby, it is possible to suppress noises such as smears and dark currents, which travel in the same direction as the vertical transfer.

As is apparent from the above description, in the camera system configured to perform the thinning-out reading drive for the CCD image sensor 21 when the monitoring mode is set,
A CCD capable of outputting a signal output Vout in which a noise component of an empty packet is put on a P phase as the CCD imaging device 21.
By using the imaging device, it is possible to suppress noises such as smears and dark currents in the same direction as vertical transfer due to correlated double sampling processing in the CDS circuit 30. Moreover, since the CDS circuit 30 is a circuit generally used to cancel low-frequency noise, there is an advantage that noise can be removed without adding a new circuit.

In the first embodiment, in order for the charge detection unit 15 to perform a reset operation between the P-phase and the D-phase of the CCD output, the cycle of the reset operation is determined by the horizontal transfer unit 14. Set the same as the transfer cycle, ie, set the frequency of the reset gate pulse RGφ to the horizontal transfer pulse H
The frequency is set to be the same as φ1 and Hφ2.
It is also possible not to perform the reset operation between the P phase and the D phase of the D output.

As described above, by preventing the reset operation from being performed between the P phase and the D phase, the frequency of the reset gate pulse RGφ can be set to の of the frequency of the horizontal transfer pulses Hφ1 and Hφ2. Power consumption can be reduced as compared with the case where the same frequency is set. In this case, the P-phase noise component is added to the D-phase as it is, and the (D-phase) is multiplied by (signal component + noise component × 2). Ingredients cannot be completely canceled.

That is, although the original noise amount for one packet included in the signal component remains, the S / S
Since the noise amount can be reduced by only one packet as compared with the related art in which N is doubled, the S / N can be improved. However, a circuit for doubling the level of the P-phase noise component is provided at a stage preceding the differential amplifier 34 of the CDS circuit 30 in FIG. 6, and the D-phase (signal component + noise component × 2) and the P-phase ( By taking the difference from (noise component × 2), it is possible to completely cancel the noise component during the signal processing.

In the first embodiment, in the thinning-out readout driving, by reading out the signal charge from each pixel every other pixel, the noise component of the empty packet and the signal component of the signal packet are reduced by 1: 1 relationship (pair)
Has been described as an example, but the present invention is not limited to thinning every other pixel.

As an example, as shown in FIG. 8, the present invention can be similarly applied to the case of the thinning-out reading drive for performing the process of thinning out the signal charges of three pixels for every four pixels in the vertical direction. The case of this thinning-out reading drive will be described below as a second embodiment. In the case of the second embodiment, in the vertical transfer unit 13, two empty packets (図 in the figure) ahead of the signal packet (図 in the figure) with respect to the signal packet (図).
And a set of one rear empty packet as a set (A). Then, the line shift is repeated four times within the horizontal blanking period. As a result, the frame rate can be improved to four times that of the all-pixel read driving.

On the other hand, as in the case of the first embodiment, the horizontal transfer section 14 has a configuration having a packet sequence (double density) twice the number of pixels in the horizontal direction, for example. In the horizontal transfer unit 14, one bit shift is performed between the second and third line shifts during the horizontal blanking period. As a result, of the packet pair, the charge of the first two empty packets is accumulated from the vertical transfer unit 13 in the packet on the front side in the horizontal transfer direction, and the signal packet and the empty space behind it are stored in the packet on the rear side. Each charge of the packet is accumulated (B).

In the charge detecting section 15, the frequency of the reset gate pulse RGφ is set to の of the frequency of the horizontal transfer pulses Hφ1 and Hφ2, as shown in the timing chart of FIG. That is, the reset operation in the charge detection unit 15 is performed at a cycle twice as long as the transfer cycle of the horizontal transfer unit 14. Thereby, the signal output V in FIG.
In the out waveform, the reset operation is not performed between the P phase and the D phase.

As a result, in the case of the thinning-out readout drive for thinning out signal charges of three pixels for every four pixels, the noise component corresponding to two empty packets is applied to the P phase, and the noise component equivalent to four empty packets is applied to the D phase. The noise component + the signal component of the above will ride.
Then, the CDS circuit 30 at the subsequent stage calculates the difference between the (signal component + noise component × 4) of the D phase and the (noise component × 2) of the P phase, thereby canceling the noise of two packets of the vertical transfer unit 13. You can do it.

By the way, in the prior art, when thinning-out read-out driving for thinning out signal charges of three pixels for every four pixels is realized, the D-phase (signal component + noise component × 4) is used.
Is output as it is, so that the S / N deteriorates four times. Further, similarly to the modification of the first embodiment, the differential amplifier 3 of the CDS circuit 30 in FIG.
A circuit for doubling the level of the P-phase noise component is provided at the stage preceding the phase No. 4 so that the difference between the (signal component + noise component × 4) of the D-phase and the (noise component × 4) of the P-phase is obtained. By doing so, it is possible to completely cancel noise components in the process of performing signal processing.

In the second embodiment, the case where the reset operation is not performed between the P phase and the D phase in the waveform of the signal output Vout in FIG. 9 has been described as an example.
As in the case of the embodiment, the reset gate pulse RGφ
Can be set to be the same as the frequency of the horizontal transfer pulses Hφ1 and Hφ2, and the reset operation can be performed between the P phase and the D phase. In this case, the CDS circuit 3
At 0, the noise component can be completely canceled by directly subtracting the P-phase component from the D-phase component.

In each of the embodiments described above, the case where the present invention is applied to the CCD image pickup device of the all-pixel read-out drive system has been described. However, the present invention is not limited to this. The present invention can be similarly applied to a CCD image pickup device using a frame readout driving method or the like.

In each of the above embodiments, the vertical transfer unit 1
In 3, it is assumed that an empty packet is arranged adjacent to a signal packet. However, the noise information to be put on the P-phase may be a signal having the same horizontal address as the signal charge to be extracted, that is, a noise component of the same vertical pixel column. Therefore, the present invention is not limited to the configuration in which an empty packet is arranged adjacent to a signal packet, and the position (address) in the vertical direction is not limited.
That is, in FIG. 10, if an address of a noise component of an empty packet to be put on the P phase is (n, X) for an arbitrary output pixel (n, m), if the horizontal address n matches, The vertical address X only has to be in the same vertical pixel column.

As an example, one empty packet is provided for the same vertical pixel column, and the address of the empty packet is (n,
0), and the noise component of the empty packet is put on the P phase. Then, in the subsequent CDS circuit, 1
When performing signal processing on a line-by-pixel basis for each line, a configuration is employed in which a P-phase noise component that is input first is held and this noise component is subtracted from a signal component including a D-phase noise component for each pixel. Even if it is adopted, it is possible to cancel noises such as smears and dark currents riding in the same direction as vertical transfer.

Further, in each of the above embodiments, when a configuration is adopted in which an empty packet is disposed adjacent to a signal packet, the horizontal transfer unit 14 has a double-density configuration, so that a noise component and a signal component (noise component) are obtained. ), The horizontal transfer unit 14 is composed of two transfer registers arranged in parallel with each other, and the two transfer registers constitute a noise component and a signal component (including a noise component). )
Can be separately transferred horizontally, and a noise component and a signal component are alternately supplied to the charge detection unit 15 in the final stage. The same operation as in the case of the double density configuration is performed in the charge detection unit 15.

[0059]

As described above, according to the present invention,
A signal packet corresponding to each of the pixels in one vertical pixel column and 1
In a solid-state imaging device comprising a packet sequence having at least one empty packet per vertical pixel array, and having a vertical transfer unit for vertically transferring signal charges read from each pixel, the components of the empty packet are added to a preset phase. By outputting the difference, the difference between the data phase component and the preset phase component of the output signal of the solid-state imaging device is obtained in the subsequent signal processing system, so that the same direction as the vertical transfer of smear and dark current is obtained. Therefore, the S / N can be improved without adding a special circuit to the signal processing system.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a solid-state imaging device according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the first embodiment.

FIG. 3 is a schematic diagram for explaining an operation in an all-pixel reading mode.

FIG. 4 is a schematic diagram for explaining an operation in a thinning-out reading mode.

FIG. 5 is a block diagram showing an example of a configuration of a camera system according to the present invention.

FIG. 6 is a block diagram illustrating an example of a circuit configuration of a CDS circuit.

FIG. 7 is a waveform chart for explaining the basic principle of the CDS circuit.

FIG. 8 is a schematic diagram for explaining the concept of a solid-state imaging device according to a second embodiment of the present invention.

FIG. 9 is a timing chart for explaining the operation of the second embodiment.

FIG. 10 is an explanatory diagram of addresses of empty packets to be put on the P phase.

FIGS. 11A and 11B are schematic diagrams for explaining the problem of the prior art, in which FIG. 11A shows the case of all-pixel read driving, and FIG. 11B shows the case of thinning-out read driving.

[Description of Signs] 12 ... light receiving element, 13 ... vertical transfer section, 14 ... horizontal transfer section, 15 ... charge detection section, 20 ... timing generation circuit, 2
DESCRIPTION OF SYMBOLS 1 ... CCD imaging device, 23 ... Signal processing circuit, 24 ... Mode setting part, 30 ... CDS (correlation double sampling) circuit

Claims (7)

[Claims] 1. A plurality of pixels arranged in a matrix, a signal packet corresponding to each of pixels in one vertical pixel column, and one
A plurality of vertical transfer units, each of which includes a packet sequence having at least one empty packet per vertical pixel column, and which vertically transfers signal charges read from the plurality of pixels; A horizontal transfer unit that transfers the charges of the signal packet and the empty packet in the horizontal direction without mixing, and sequentially converts the charges transferred from the horizontal transfer unit into an electric signal, and converts the components of the empty packet. A solid state imaging device comprising: a charge detection unit that outputs a component of the signal packet on a data phase and outputs the signal packet on a preset phase. 2. The plurality of vertical transfer units have at least one empty packet for each signal packet corresponding to each pixel of one vertical pixel column, and the horizontal transfer unit includes the plurality of vertical transfer units. The solid-state imaging device according to claim 1, wherein the charge of the signal packet and the charge of the empty packet supplied from a transfer unit are paired and transferred in the horizontal direction. 3. The solid-state imaging device according to claim 2, wherein the horizontal transfer unit includes an array of packets twice as many as the number of pixels in the horizontal direction. 4. The solid-state imaging device according to claim 3, wherein the charge detection unit performs a reset operation in the same cycle as a transfer cycle of the horizontal transfer unit. 5. The solid-state imaging device according to claim 3, wherein the charge detection unit performs a reset operation at a cycle twice as long as a transfer cycle of the horizontal transfer unit. 6. A packet sequence comprising a plurality of pixels arranged in a matrix, a signal packet corresponding to each pixel in one vertical pixel column, and a packet sequence having at least one empty packet per vertical pixel column. In a solid-state imaging device comprising: a plurality of vertical transfer units for vertically transferring signal charges read from a plurality of pixels, wherein each of the signal packet and the empty packet supplied from the plurality of vertical transfer units The charges are transferred in the horizontal direction without mixing, the charges transferred in the horizontal direction are sequentially converted into electric signals, the components of the empty packets are put on a preset phase, and the components of the signal packets are put on a data phase and output. A method for driving a solid-state imaging device, comprising: 7. A packet sequence comprising a plurality of pixels arranged in a matrix, a signal packet corresponding to each pixel in one vertical pixel column, and a packet sequence having at least one empty packet per vertical pixel column. A plurality of vertical transfer units for transferring signal charges read from a plurality of pixels in the vertical direction; and a horizontal transfer without mixing the charges of the signal packets and the empty packets supplied from the plurality of vertical transfer units. A horizontal transfer unit for transferring in the direction, and the charges transferred from the horizontal transfer unit are sequentially converted into an electric signal, the components of the empty packet are put on a preset phase, and the components of the signal packet are put on a data phase and output. A solid-state imaging device including a charge detection unit; and a mode for selectively setting a normal imaging mode or a monitoring mode as an imaging mode for the solid-state imaging device. A camera, comprising: a setting unit; and a signal processing circuit which receives an output signal of the solid-state imaging device as input, and performs a process of calculating a difference between a preset phase component and a data phase component in the output signal. system.