JPH0998349A - Solid-state image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the resolution and to reduce moire by compensating deficient signals at positions corresponding to element isolation regions with in horizontal and vertical directions. SOLUTION: Signal picture elements generated corresponding to signal outputs of one line of an object and stored in picture element arrays 130, 160 are transferred to adjacent picture element arrays 140, 170, the charges are photoelectric- converted corresponding to signal outputs of the same line of an object. Then the signal picture elements stored in the picture element arrays 140, 170 are transferred to adjacent picture element arrays 150, 180, in which the charges are photoelectric-converted similarly. Then the charges in the picture element arrays 150, 180 are transferred to memory arrays 260, 270, from which the charges are transferred to a shift register 30. Then the charges are outputted serially externally via an output circuit 31 by the shift register 30. Thus, the 1st and 2nd picture elements are interpolated with each other by the picture elements shifted in the shift register 30 in this way. Thus, the resolution is improved and moire is redued.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device constituting a linear sensor, and more particularly to a TDI (Time Delay In
It is used for a linear sensor in the integration mode.

[0002]

2. Description of the Related Art First, the basic principle of a linear sensor will be described. FIG. 3 shows the structure of this linear sensor. In this figure, this linear sensor has pixels 11 to 1
The pixel array 10 is composed of 4 pixels, the electrode array 20 is composed of shift electrodes 21 to 24, the CCD shift register 3 and the output circuit 4. The pixels 11 to 14 are one-dimensionally arranged in the horizontal direction, the shift electrodes 21 to 24 are provided to face the pixels 11 to 14, the CCD shift register 3 is arranged along the shift electrodes 21 to 24, and the output circuit 4 is a CCD. It is arranged at the output end of the shift register 3.

Pixels 11-14 accumulated by photoelectric conversion
Are transferred to the CCD shift register 3 by the shift electrodes 21 to 24, and the charges in the CCD shift register 3 are transferred from the output circuit 4 to the outside. During the charge transfer operation for one line in the CCD shift register 3, charge accumulation for the next line is performed in the pixels 11-14.

By the way, this type of sensor has a so-called TDI mode in which a plurality of pixel rows are provided to improve the sensitivity. FIG. 4 shows the structure. What is shown in the figure is a pixel column 50 composed of pixels 51 to 54 and a pixel 71.
To 74, a pixel column 90 including pixels 91 to 94, a CCD shift register 11, an output circuit 12, and an electrode column including shift electrodes 61 to 64 for transferring charges of the pixels 51 to 54 to the pixels 71 to 74. 60 and pixels 71 to 74
Shift electrodes 81 to 8 for transferring the electric charges of the pixels to the pixels 91 to 94
The charge of the electrode array 80 composed of four and the pixels 91 to 94 is CCD
Shift electrodes 101 to 10 transferred to the shift register 11
It is provided with an electrode array 100 composed of 4 and an output circuit 12 for transferring the charges of the CCD shift register 11 to the outside.

In the actual operation in such a configuration, the shift electrodes 101 to 104 are opened, and the pixels 91 to 9 are transferred to the CCD shift register 11 which has completed the reading of the signal of one line.
4 of the signal charge train, and then shift electrodes 101 to 10
4, the shift electrodes 81 to 84 are opened, and the pixel 71
To 74 of the signal charges are transferred to the pixels 91 to 94, and then the shift electrodes 81 to 84 are closed and the shift electrodes 61 to 6 are closed.
4 is opened, and the signal charge sequence of the pixels 51 to 54 is set to the pixels 71 to 7
After transferring to No. 4, the shift electrodes 61 to 64 are closed, and photoelectric conversion is performed in each pixel column.

In the TDI mode linear sensor, the photoelectric conversion period is equal to the number of pixel rows by the above operation.
It can be doubled and the sensitivity can be increased.

[0007]

However, the conventional TDI mode line sensor has the following problems.

First, the horizontal pitch Ph0 is the pixel width Wh.
, The element isolation width Gh. That is, Ph0 = Wh + Gh.

Therefore, an invalid area is formed by the element isolation width Gh. This means that in the case of the TDI method, the vertical pitch is determined by the vertical pixel width Gv0, but the horizontal resolution is reduced by this element separation.

Further, since the pixels constituting each pixel row are independent from each other, when an object having vertical stripes of about the same pitch as the pixel pitch is incident on the pixel row, an image of the object and the pixel row are formed. Moire development occurs between them, resulting in a bead-like repeating pattern of light and shade, which deteriorates the image quality.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to prevent the deterioration of the degree of integration due to the element isolation region in the horizontal direction and to reduce the moire phenomenon. An object of the present invention is to provide a solid-state imaging device that constitutes a mode linear sensor.

[0012]

A solid-state image pickup device according to the present invention is arranged with a first pixel row composed of a plurality of pixels and a half-pitch offset in the horizontal and vertical directions with respect to the first pixel row. A second pixel column composed of a plurality of pixels, a charge storage section for storing signal charges to be transferred to the signal processing means, and a first pixel line to transfer the signal charges of the first pixel column to the second pixel column. Shift electrode and a second shift electrode for transferring the signal charge of the second pixel column to the charge storage section.

The charge storage section can be configured to store all the signal charges of both the first and second pixel columns.

The charge storage section stores a signal charge corresponding to each pixel forming the first pixel column and a signal charge corresponding to each pixel forming the second pixel column. And a second memory that stores the data.

Further, the charge storage section can be configured to include a CCD shift register for storing the signal charges of the first and second memories.

Next, the signal processing means preferably comprises an interpolating means for interpolating the signal output of one of the first pixel row and the signal output of the second pixel row.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the structure of a solid-state imaging device according to an embodiment of the present invention. In the figure, a pixel array 130 including pixels 131, 132, ...
1, 142, ..., and a pixel array 140 and pixels 151, 1
A pixel row 150 composed of 52, ... Corresponds to a first pixel row, and a pixel row 160 composed of pixels 161, 162, ... And a pixel row 170 composed of pixels 171, 172 ,.
A pixel row 180 including 1, 182, ... Corresponds to the second pixel row. The first and second pixel columns are arranged with a half pitch shift in the horizontal and vertical directions.

Between the pixel row 130 and the pixel row 160,
A shift electrode array 1 including shift electrodes 191, 192, ...
90 is provided and is responsible for charge transfer from the former to the latter. Similarly, a shift electrode row 200 including shift electrodes 201, 202, ... Is provided between the pixel row 160 and the pixel row 140, and the pixel row 140 and the pixel row 170 are provided.
A shift electrode array 210 including shift electrodes 211, 212, ... Is provided between the pixel array 170 and the pixel array 170.
A shift electrode array 220 composed of shift electrodes 221, 222, ... Is provided between the pixel array 150 and the pixel array 50, and a shift electrode array 190 composed of shift electrodes 231, 232 ,. Are provided, and each pair of pixel columns is responsible for charge transfer from the former to the latter.

A memory 261 is provided on the output side of the pixel array 180.
A memory array 260 composed of 262, ...
A memory column 270 composed of 72, ... Is arranged, and each of the pixels 181, 182 ,.
One memory is allocated to each of the two memory arrays 260 and 270. Pixel column 180 and memory column 260
A shift electrode array 240 composed of shift electrodes 241, 242, ... Is provided between and, and charges are transferred from the former to the latter by this electrode. Pixel row 1
80 and the memory column 270 between the shift electrodes 251, 25.
A shift electrode array 250 composed of 52, ... Is provided, and charges are transferred from the former to the latter by this electrode. The shift register 30 is disposed on the output side of the memory columns 260 and 270, the shift electrode column 280 including the shift electrodes 281, 282, ... Is disposed between the memory column 260 and the shift register 30, and the memory column 270.
Between the shift register 30 and the shift register 30.
A shift electrode array 290 composed of 92, ... Is arranged. The charges in the memory columns 260 and 270 are transferred to the shift register 30 by the shift electrode columns 280 and 290. An output circuit 31 is provided on the output side of the shift register 30.
The output circuit 31 serially outputs the electric charge of the shift register 30 to an external signal processing circuit. The signal processing means includes an interpolation circuit that interpolates the signal output of one of the first pixel row and the signal output of the other pixel row. This interpolation circuit outputs the output of the first pixel row 140 to the second pixel rows 160 and 170, for example.
Of the pixel 142
When paying attention to, for example, the area A surrounded by this and surrounded by the alternate long and short dash line becomes the interpolation target area. in this case,
Each of the second pixels 161 and 16 adjacent to the four sides of the pixel 142
2,172,171 signals will be used to make up for the insufficient signal of pixel 142.

Next, the TD constructed as described above
The operation of the I-mode linear sensor will be described. Pixel row 13 generated corresponding to the signal output of one line of the subject
0, the signal pixel row accumulated in the pixel row 160 is transferred to the adjacent pixel rows 140 and 170, and photoelectric conversion corresponding to the signal output of the same line of the subject is performed here. afterwards,
The signal pixel rows accumulated in the pixel rows 140 and 170 are transferred to the adjacent pixel rows 150 and 180, and photoelectric conversion corresponding to the signal output of the same line of the subject is performed here. After that, the charges of the pixel columns 150 and 180 are transferred to the memory columns 260 and 270, and then transferred from the memory columns 260 and 270 to the shift register 30.
Then, the shift register 30 is operated, and the charge is serially output from the output circuit 31 to the outside. By unifying the pixel columns to the shift register 30 as described above, the first and second pixels are integrated.
It becomes possible to improve the resolution in the horizontal direction by interpolating the pixel rows of.

The TD of the structure of the present invention is the same as the conventional TDI.
Even in the I-mode linear sensor, in actual operation, the control electrodes 281 and 291 are opened and the memory electrode rows 261 and 291 are opened.
CC for which the signal line of the signal charge train of is completely read
After transferring to the D shift register, the control electrodes 281, 29
1 is closed and the shift electrode 241 is closed, the shift electrode 251 is opened to transfer the signal charge sequence of the pixel column 181 to below the memory electrode column 261 and 271, and then the shift electrode 251 is closed and the shift electrodes 241 and 231. Open the pixel column 151
The signal charge train of is transferred below the memory electrode train 271. Next, after closing the shift electrode 241, the shift electrodes 231 and 22
1 is opened, the signal charge column of the pixel column 171 is transferred to the pixel column 181, and thereafter, similarly from the pixel column 141 to the pixel column 151,
The signal charge is transferred from the pixel row 161 to the pixel row 171, and from the pixel row 131 to the pixel row 141, and the image of the subject is moved to the corresponding pixel row, and the next photoelectric conversion is performed.

After that, the above operation is sequentially repeated to transfer in the TDI mode.

The advantages of this embodiment described above are shown below.

Information on the element isolation region between the pixels of one pixel column can be picked up by the adjacent second pixel column, and the resolution is improved.

FIG. 3 is for explaining the effect,
In this figure, Ph0 is the conventional horizontal resolution pitch,
Pv0 is the conventional vertical resolution pitch, Ph1 is the horizontal resolution pitch of the present invention, and Pv1 is the vertical resolution pitch of the present invention. As shown in FIG. 3A, in the conventional pixel arrangement, since the pixels are not displaced, information between pixels cannot be read. In contrast, in the present invention shown in FIG. Information can be picked up by adjacent pixel rows, and the conventional resolution can be doubled by synchronizing with the scanning speed of the subject.

Further, since the adjacent pixel rows are displaced by a half pitch also in the vertical direction resolution, the conventional resolution can be almost doubled also in the vertical direction.

Further, in the present invention, since transfer is performed in a meandering shape when transferring between pixel columns, the horizontal width of the sensitivity distribution of pixels is expanded by lengthening the residence time in adjacent pixel columns. be able to. For this reason, the skirts of the sensitivities of the respective pixels overlap with each other, and moire can be reduced.

The invention is capable of several variants.
Hereinafter, modified examples will be described. (1) In the above description, the signal charge sequences of the pixel columns 151 and 181 are transferred to the CCD shift register 30 and taken out as one time-series signal charge sequence from the output circuit, and the pixels between the pixel columns 150 are separated by pixels. Although the interpolation is performed by the pixels in the column 180, the present invention may use the pixel column 150 and the pixel column 180 as independent signal charge columns. That is, pixel row 1
It is also possible to use 50 and 180 as two separate signal charge sequences instead of one signal charge sequence, and record according to the pixel arrangement. Even in this case, the pixel rows 18 are provided between the pixel rows 150.
Interpolation is performed at 0, and the horizontal resolution remains high. Moreover, the resolution in the vertical direction does not have to be deteriorated by reading and recording independently. (2) The horizontal CCD shift register is read out for each pixel column by making the number of transfer stages equal to that of each pixel column,
The memory electrode and the control electrode may be omitted. (3) The first pixel row and the second pixel row have been described as three rows in the above description, but this number can be arbitrarily set and may be one for each. (4) The combination of the pixel column and the shift electrode may be a CCD transfer electrode structure.

[0029]

As described above, according to the present invention, it corresponds to a portion which cannot be covered by the first pixel row and the second pixel row in the screen, that is, the element isolation region in the horizontal direction and the vertical direction. Since the signal shortages at the locations are mutually compensated, the resolution can be improved, and the transfer between the pixel columns is a meandering transfer, and thus the moire phenomenon can be reduced.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram showing the effect of the present invention.

FIG. 3 is a schematic diagram showing a structure of a conventional solid-state imaging device having one row of pixels.

FIG. 4 is a schematic diagram showing a structure of a conventional TDI mode solid-state imaging device having a plurality of columns of pixels.

[Explanation of symbols]

 130-150 1st pixel row 160-180 2nd pixel row 190-250,280,290 Shift electrode 260,270 Memory 30 Shift register 31 Output circuit

Claims (5)

[Claims] 1. A first pixel column composed of a plurality of pixels, and a second pixel column composed of a plurality of pixels arranged at a half pitch in the horizontal and vertical directions with respect to the first pixel column. A charge storage unit that stores signal charges to be transferred to the signal processing unit; a first shift electrode that transfers the signal charges of the first pixel column to the second pixel column; A solid-state imaging device comprising: a second shift electrode that transfers a signal charge to the charge storage unit. 2. The solid-state imaging device according to claim 1, wherein the charge storage section stores all signal charges of both the first and second pixel columns. 3. The charge storage section includes a first memory for storing signal charges corresponding to respective pixels forming the first pixel column, and a signal corresponding to respective pixels forming the second pixel column. The solid-state imaging device according to claim 1, further comprising a second memory that stores electric charges. 4. The solid-state imaging device according to claim 1, wherein the charge storage unit includes a CCD shift register that stores signal charges of the first and second memories. apparatus. 5. The signal processing means comprises an interpolating means for interpolating the signal output of one of the first pixel row and the signal output of the other of the second pixel row. 3. The solid-state imaging device according to any one of 3.