JP2002218327A - Solid-state imaging device and camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state imaging device which can cope with an increased number of channels, exceeding four channels, and to provide a camera system which uses the imaging device as an imaging device. SOLUTION: In an imaging unit 11, vertical transfer registors 13 are divided into groups of vertical transfer registers 13AL and 13AR, at both its sides and a group of vertical transfer registers 13B in its center, and the number of transfer stages of the vertical transfer registers in the center being set larger than the number of the vertical transfer registers 13AL and 13AR at both the sides. One group of horizontal transfer registers is arranged at each transfer destinations side of the vertical transfer register groups 13AL and 13AR, that is, the total of two horizontal transfer registers 13AL and 13AR are arranged at each side thereof, and for example, two horizontal transfer registers 14BL and 14BR are arranged at the transfer destination side of the vertical transfer register group 13B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device and a camera system, and more particularly to a solid-state image pickup device having a plurality of horizontal transfer units for an image pickup unit in which pixels are two-dimensionally arranged, and an image pickup of the same. It relates to a camera system used as a device.

[0002]

2. Description of the Related Art Conventionally, in an area-type solid-state imaging device in which pixels are two-dimensionally arranged, particularly in a multi-pixel solid-state imaging device exceeding one million pixels, it is necessary to increase the frame rate. By arranging a plurality of horizontal transfer registers (horizontal transfer units) or dividing the pixel area of the image pickup unit in the horizontal / vertical directions, multichannel output signals are being promoted.

As the prior art 1, as shown in FIG. 6, an image pickup unit 103 in which pixels 101 are two-dimensionally arranged and a vertical transfer register 102 is arranged for each vertical column of the pixels 101 is provided. A solid-state imaging device having a configuration in which two horizontal transfer registers 104 and 105 are juxtaposed is known.

In the case of the solid-state imaging device according to the prior art 1, for example, signal charges of odd-numbered pixel columns are transferred from the vertical transfer register 102 to one horizontal transfer register 104, and signal charges of even-numbered pixel columns are transferred to the other horizontal transfer register. The signals are transferred to the registers 105, respectively, horizontally transferred in parallel by the horizontal transfer registers 104, 105, and are derived as two-channel output signals OUT1, OUT2 through the charge detection units 106, 107.

[0005] As prior art 2, as shown in FIG. 7, an image pickup section 203 in which pixels 201 are two-dimensionally arranged and a vertical transfer register 202 is arranged for each vertical column of the pixels 201. 2. Description of the Related Art There is known a solid-state imaging device having a configuration in which a pixel area is vertically divided into two parts in a horizontal direction, for example, and horizontal transfer registers 204 and 205 are arranged one for each of the two divided pixel areas.

In the case of the solid-state imaging device according to the prior art 2, the signal charges in the pixel area on the left side of the imaging unit 203 are stored in the left horizontal transfer register 204, and the signal charges in the right pixel area are stored in the right horizontal transfer register. 205
Horizontal transfer is performed in the reverse direction by the horizontal transfer registers 204 and 205, and the signals are derived as two-channel output signals OUT1 and OUT2 through the charge detection units 206 and 207.

As in the solid-state imaging devices according to the prior arts 1 and 2, by adopting a configuration having, for example, two horizontal transfer registers for the imaging unit, each of these horizontal transfer registers transfers one line. The amount of signal charge
Since the driving frequency of horizontal transfer can be halved, the rate of outputting pixel information for one screen per unit time, that is, the frame rate can be doubled, because the horizontal transfer register is halved when one is used. become.

[0008]

However, in the solid-state imaging device according to the prior art 1, in the case of the above example, the signal charges of the even-numbered pixel columns are transferred from the vertical transfer register 102 to the outer horizontal transfer register 105. In addition, the signal charge is transferred from the horizontal transfer register 104 to the horizontal transfer register 105. If the charge transfer between the horizontal transfer registers is further increased, it is necessary to consider the transfer deterioration of the signal charge. 2 channels are the limit.

In the solid-state imaging device according to the prior art 2, the two horizontal transfer registers 204 and 205 must be arranged linearly so that the transfer directions are reversed. Since it is not possible to arrange three or more, two channels are the limit. If the pixel area of the imaging unit 203 is further divided into two in the vertical direction, two channels on one side and four channels on both sides are the limits. It could not cope with multi-channel.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a solid-state imaging device capable of supporting multi-channels exceeding four channels and a camera system using the same as an imaging device. To provide.

[0011]

According to the present invention, there is provided a solid-state imaging device comprising: a pixel group in which pixels are two-dimensionally arranged; and a pixel group arranged along a vertical pixel column of the pixel group. A first vertical transfer unit group for transferring the signal charges read from the columns in at least one direction, and a different vertical transfer unit group having a greater number of transfer stages than the first vertical transfer unit group. A second vertical transfer unit group arranged in the pixel column and transferring the signal charges read from the corresponding pixel column of the pixel group in at least one direction; and a signal charge transferred from the first vertical transfer unit group. A configuration including a first horizontal transfer unit group that transfers the data charges in two systems and a second horizontal transfer unit group that transfers the signal charges transferred from the second vertical transfer units in at least two systems. It has become. The solid-state imaging device is used as an imaging device in a camera system.

In the solid-state image pickup device having the above structure or a camera system using the same, the signal charges of each pixel of the pixel group are read out by being divided into first and second vertical transfer units for each vertical pixel column. The data is vertically transferred by the vertical transfer unit group and transferred to the first and second horizontal transfer unit groups. At this time, since the number of transfer stages of the first and second vertical transfer units is different, the first and second horizontal transfer units are arranged at different positions in the vertical direction. The first horizontal transfer unit group horizontally transfers the signal charges transferred from the first vertical transfer unit group into two systems, and the second horizontal transfer unit group transfers the signal charges from the second vertical transfer unit group. The obtained signal charges are horizontally transferred in at least two systems. As a result, it is possible to derive output signals for two channels in the first horizontal transfer unit group and two or more channels in the second horizontal transfer unit group, for a total of four or more channels.

[0013]

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 configuration example of a solid-state imaging device according to an embodiment of the present invention. The solid-state imaging device according to the present embodiment has a configuration including an imaging unit, a horizontal transfer unit, and a charge detection unit as basic components.

In FIG. 1, an image pickup section 11 includes a pixel group in which a large number of pixels 12 are two-dimensionally arranged, and a vertical pixel column of these pixel groups provided along the arrangement direction to read from each pixel. The area sensor has a vertical transfer register (vertical transfer unit) 13 for vertically transferring the output signal charges. Here, for simplification of the drawing, 7
The case of a pixel array of 8 rows and 8 columns will be described as an example.

In the image pickup section 11, the pixel 12 is formed by a photoelectric conversion element such as a photodiode. The vertical transfer register 13 is formed by, for example, a CCD. In the case of this example, this vertical transfer register 13 has four vertical transfer register groups 13A, two on each side.
And a central four vertical transfer register group 13B. Then, for example, the vertical transfer register group 13A
Has a transfer stage number corresponding to the number of pixels in the vertical direction, whereas the vertical transfer register group 13B has a larger transfer stage number than the vertical transfer register group 13A.

Here, in the vertical transfer register, each transfer stage is usually formed with a fixed pitch. Therefore, the fact that the number of transfer stages of the vertical transfer register group 13B is larger than that of the vertical transfer register group 13A means that the vertical transfer register group 13B has a longer register length than the vertical transfer register group 13A, as is apparent from FIG. Becomes longer.
In the following description, the left vertical transfer register group 13
A is referred to as a vertical transfer register group 13AL, and the right vertical transfer register group 13A is referred to as a vertical transfer register group 13AR.

Each of the vertical transfer register groups 13AL and 13AR has one horizontal transfer register 1 at each transfer destination side.
4AL and 14AR are provided. Horizontal transfer register 1
4AL and 14AR have a vertical transfer register group 13AL,
Signal charges are sequentially transferred from 13AR. The horizontal transfer registers 14AL and 14AR horizontally transfer the signal charges transferred from the vertical transfer register groups 13AL and 13AR in opposite directions.

On the transfer destination side of the vertical transfer register group 13B, for example, two horizontal transfer registers 14BL, 14BR
Is arranged. Horizontal transfer registers 14BL, 14BR
, The signal charge is transferred from the vertical transfer register group 13B into two systems, that is, a left system and a right system. The horizontal transfer registers 14BL and 14BR also horizontally transfer the signal charges transferred from the vertical transfer register group 13B in opposite directions.

Horizontal transfer registers 14AL, 14AR, 1
At the end of each of the transfer destinations of the 4BL and 14BR, for example, a charge detection unit 15AL, 15AR, 15BL, 15BR having a floating diffusion amplifier configuration is provided. These charge detectors 15AL, 15AR, 15B
L and 15BR are horizontal transfer registers 14AL and 14A
R, 14BL, and 14BR detect the signal charges transferred thereto, convert them into voltages, and output signals O of four channels.
Output as UT1, OUT2, OUT3, OUT4.

In the solid-state imaging device according to the present embodiment having the above-described configuration, the center vertical transfer register group 13B has a shape in which the transfer stages are extended with respect to the left and right vertical transfer register groups 13AL and 13AR. Considering the transfer (transfer) of the signal charge to the horizontal transfer registers 14BL and 14BR, the number of transfer stages of the extension part in the vertical transfer register group 13B is an integral multiple of the number of phases of the vertical transfer method.
For example, in the case of four-phase driving, it is preferable to set four stages, eight stages, twelve stages,....

The horizontal transfer registers 14AL and 14A
It is preferable to set the same number of transfer stages for each of the transfer stages R, 14BL, and 14BR. Thus, the horizontal transfer registers 14AL, 14AR, 14BL,
By setting the same number of transfer stages for each of the 14BRs, the horizontal transfer registers 14AL, 14AR, 14BL, 14
BR can be driven by a common transfer clock, and the configuration of the drive system can be simplified accordingly.

Next, the cycle of the four-channel output signals OUT1, OUT2, OUT3, and OUT4 according to the present embodiment will be described in comparison with the two-channel output signals OUT1, OUT2 according to the prior art 2 shown in FIG. I do. FIG. 2 shows the output signal O of four channels according to the present embodiment.
FIG. 3 is a timing chart of UT1, OUT2, OUT3, and OUT4, and FIG. 3 is a timing chart of two-channel output signals OUT1 and OUT2 according to the related art 2.

First, in the timing chart of FIG. 3, a two-channel output signal OUT according to prior art 2 is shown.
Assuming that the output period of 1, OUT2 is t, the cycle Tb is the output period t + vertical blanking period v. On the other hand, the output signal OUT of four channels according to the present embodiment is
In the case of 1, OUT2, OUT3, and OUT4, as is clear from the timing chart of FIG. 2, the output period of these signals is の of the output period t when outputting two channels, and is reduced to half (t / 2). Is done.

However, as for the output signals OUT3 and OUT4, since the transfer stage of the vertical transfer register group 13B is extended, as shown in the timing chart of FIG. 2, the vertical transfer at the extended transfer stage portion is performed. Period t '
The output signals OUT1 and OUT2 are delayed by the amount corresponding to the output signals OUT1 and OUT2. Therefore, the output signal OUT of four channels
Output period Ta of OUT1, OUT2, OUT3, OUT4
Does not simply become １ ／ even if the number of channels is doubled. However, when viewed from the entire period Ta, the ratio of the vertical transfer period t 'in the extended transfer stage portion occupies only a small amount, so that it is sufficiently effective to increase the signal output period, that is, increase the frame rate. It can be said.

The signals OUT1, OUT1 output on the four channels
OUT2, OUT3, and OUT4 are rearranged into signals of one line (one line) corresponding to the pixel arrangement of the imaging unit 11 using a memory or the like in a signal processing system at a subsequent stage.
Specifically, considering the transfer direction of the horizontal transfer registers 15AL and 15BL as a reference, the horizontal transfer registers 15A
Since the transfer directions of R and 15BR are opposite, the order of the output signals OUT2 and OUT4 is inverted to output signals OUT2X and OUT4X, and output in the order of OUT1 → OUT3 → OUT4X → OUT2X. The signal processing may be performed for each line.

In the above embodiment, the signal charges vertically transferred by the central vertical transfer register group 13B are divided into two systems and transferred to the two horizontal transfer registers 14BL and 14BR, whereby the output signals of four channels are output. Has been described as an example, but the present invention is not limited to this.

More specifically, the signal charges vertically transferred by the vertical transfer register group 13B are divided into three or more systems, preferably even systems (4 systems, 6 systems,...), And four, six,.
By adopting a configuration to transfer to the horizontal transfer register of
It is possible to increase the number of channels beyond the number of channels. In this case, naturally, the vertical transfer register group 13
As in the relationship between A and the vertical transfer register group 13B,
In the vertical transfer register group 13B, a plurality of register groups having different numbers of transfer stages are provided.

In the above embodiment, the case where the pixel area of the imaging unit 11 is divided only in the horizontal direction has been described as an example. However, the pixel area of the imaging unit 11 is also divided into two in the center in the vertical direction. And the vertical transfer register group 13A,
By adopting a configuration in which the driving of the 13B is performed in a direction opposite to each other (vertical direction in the drawing), it is possible to further increase the number of channels.

That is, as shown in FIG. 4, similar to the horizontal transfer registers 14AL, 14AR, 14BL, 14BR and the charge detection units 15AL, 15AR, 15BL, 15BR, the horizontal transfer registers are also provided on the opposite side of the imaging unit 11. By arranging the registers 16AL, 16AR, 16BL, 16BR and the charge detection units 17AL, 17AR, 17BL, 17BR, it is possible to realize eight channels of output signals. Further, as in the case of the modification of the previous embodiment, the signal charges vertically transferred by the vertical transfer register group 13B are reduced by 3%.
By dividing the system into more than one system, preferably even systems, it is possible to further increase the number of channels.

The solid-state imaging device according to the present embodiment described above is suitable for use as an imaging device in a camera system such as a video camera.

FIG. 5 is a block diagram schematically showing the configuration of the camera system according to the present invention. In FIG. 5, image light (incident light) from a subject (not shown) passes through an optical system such as a lens 21 or the like, and a CCD imager (imaging device) 2.
An image is formed on the second imaging surface. This CCD imager 22
The solid-state imaging device according to the above-described embodiment is used.

The CCD imager 22 is driven by a CCD drive circuit 23 in various manners such as reading out signal charges from pixels, vertical transfer, and horizontal transfer. When the solid-state imaging device having the configuration shown in FIG. 1 is used, four-channel signals OUT1 and OUT are output from the CCD imager 22.
2, OUT3 and OUT4 are output. These signals O
The UT1, OUT2, OUT3, and OUT4 are subjected to signal processing such as CDS (correlated double sampling) in the analog signal processing circuit 24.

The four-channel signals OUT1, OUT2, OUT3, and OUT4 that have passed through the analog signal processing circuit 24
Is converted into a digital signal by an AD converter 25, and then supplied to a digital signal processing circuit 26 including a memory and the like. The digital signal processing circuit 26 inverts the order of the pixel signals of the signals OUT2 and OUT4 to obtain signals OUT2X and OUT4X, and outputs the signals OUT2X and OUT4X.
Various signal processes such as a process of outputting in the order of 1 → OUT3 → OUT4X → OUT2X are performed.

As described above, in a camera system such as a video camera, by using the solid-state imaging device according to the above-described embodiment as an imaging device, the solid-state imaging device can support multi-channel output exceeding four channels. Since the frame rate can be increased,
Higher speed imaging can be realized.

[0035]

As described above, according to the solid-state imaging device of the present invention, it is possible to cope with multi-channels exceeding four channels, so that the frame rate can be increased and the signal between the horizontal transfer units can be realized. Since charge transfer is not required, there is no need to consider transfer deterioration.

[Brief description of the drawings]

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

FIG. 2 shows a 4-channel output signal OU according to the embodiment.
It is a timing chart of T1, OUT2, OUT3, and OUT4.

FIG. 3 shows a two-channel output signal OU according to prior art 2.
It is a timing chart of T1 and OUT2.

FIG. 4 is a schematic configuration diagram illustrating a configuration example of a solid-state imaging device according to another embodiment of the present invention.

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

FIG. 6 is a schematic configuration diagram illustrating a configuration of a solid-state imaging device according to Conventional Technique 1.

FIG. 7 is a schematic configuration diagram illustrating a configuration of a solid-state imaging device according to Conventional Technique 2.

[Explanation of symbols]

11: imaging unit, 12: pixel (photodiode), 13
... vertical transfer registers, 13AL, 13AR, 13B ... vertical transfer registers, 14AL, 14AR, 14BL, 1
4BR, 16AL, 16AR, 16BL, 16BR ... horizontal transfer register, 15AL, 15AR, 15BL, 15
BR, 17AL, 17AR, 17BL, 17BR ... Charge detector

Claims (6)

[Claims] 1. A pixel group in which pixels are two-dimensionally arranged, and at least one signal charge arranged along a vertical pixel column of the pixel group and read from a corresponding pixel column of the pixel group. A first vertical transfer unit group for transferring data in the first direction, a first vertical transfer unit group having a larger number of transfer stages than the first vertical transfer unit group, and arranged in a different vertical pixel column from the first vertical transfer unit group; A second vertical transfer unit group for transferring the signal charges read from the corresponding pixel columns of the group in at least one direction; and transferring the signal charges transferred from the first vertical transfer unit group into two systems. A solid state comprising: a first horizontal transfer unit group for transferring a signal charge transferred from the second vertical transfer unit group; and a second horizontal transfer unit group for transferring the signal charges divided into at least two systems. Imaging device. 2. The method according to claim 1, wherein the number of transfer stages of the second vertical transfer unit group greater than that of the first vertical transfer unit group is an integral multiple of the number of phases of the vertical transfer system. Solid-state imaging device. 3. The solid-state imaging device according to claim 1, wherein the second vertical transfer unit group includes a plurality of vertical transfer unit groups having different numbers of transfer stages. 4. The first and second horizontal transfer unit groups are provided only on one side of the pixel group in the transfer direction of the first and second vertical transfer unit groups. The solid-state imaging device according to claim 1. 5. The method according to claim 1, wherein the first and second horizontal transfer units are provided on both sides of the pixel group in the transfer direction of the first and second vertical transfer units. The solid-state imaging device according to claim 1. 6. An image pickup device for picking up an image of a subject, comprising: a pixel group in which pixels are two-dimensionally arranged; and a pixel group arranged along a vertical pixel column of the pixel group and read from a corresponding pixel column of the pixel group. A first vertical transfer unit group for transferring the output signal charges in at least one direction; and a vertical group different from the first vertical transfer unit group having a greater number of transfer stages than the first vertical transfer unit group. A second vertical transfer unit group arranged in a pixel column and transferring signal charges read from a corresponding pixel column of the pixel group in at least one direction; and a signal transferred from the first vertical transfer unit group. A first horizontal transfer unit group for transferring charges in two systems; and a second horizontal transfer unit group for transferring signal charges transferred from the second vertical transfer units in at least two systems. Using a solid-state imaging device La system.