JPH0334455A - Photoelectric conversion apparatus - Google Patents

Abstract

PURPOSE:To approximately double the resolution without dropping sensitivity even if different color filters are placed by a method wherein inside a photoelectric conversion element is divided into a high opening region and a low opening region where opening rate drops due to wiring or the like while the high opening region and the low opening region are made adjacent to each other. CONSTITUTION:A pixel being a photoelectric conversion element is such that the upper half is a high opening region S1 and the lower half is a low opening region S2 or the upper half is a low opening region S2 and the lower half is the high opening region S1. The structure of pixels in a first line is such that the upper half is the high opening region S1 and the lower half is the low opening region S2 wherein they are two-dimensionally placed so that the high opening regions S1 and the low opening regions S2 exhibit checkers. As for placement of color filters, Cr (chrome) is placed at the low opening region S1 while W (white) is placed at the high opening region S1 positioned at the lower half of a cell. On the high opening region S1 positioned on the upper half of the cell, Ye(yellow) or Cy(cyan) is placed wherein Ye and Cy filters are placed alternatively with respect to longitudinal and lateral directions. Thus compared to a conventional method wherein one color filter is placed in one cell to obtain a brightness signal by summing up signals of two lines, the mentioned method can double the vertical resolution.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a photoelectric conversion device, and particularly to a photoelectric conversion device composed of a plurality of photoelectric conversion elements. [Prior Art] The cell arrangement of a conventional single-chip color solid-state imaging device is as follows. FIG. 4 is an explanatory diagram showing a cell arrangement of a conventional two-dimensional solid-state imaging device. One square represents a unit cell, and the types of color filters placed on this unit cell are A, B, and C. It is represented by D. When reading out signals from such a unit cell, two rows are read out simultaneously. In the normal incremental method, for example, in an odd field, the signals are read out from the first and second rows, the third and fourth rows, and the fifth row. Read scanning is performed in the order of , 6th line, etc., and in the even field,
2nd and 3rd rows, 4th and 5th rows, 6th and 7th rows,
The readout scan is performed in the order of . Among the two rows of signals, red, green, and blue color signals are obtained from the signals from the cells corresponding to the A, B, C, and D color filters, respectively. Also, the summed signals of two rows, i.e. (
A+C) and (B+D) become luminance signals. As described above, the luminance signal and color signal necessary for the color signal can be obtained by reading out two rows simultaneously.

[Problem to be solved by the invention]

However, in the cell array of the two-dimensional solid-state imaging device described above, the luminance signal that determines the resolution is created by adding two rows, so compared to the black-and-white method that reads out each row,
Vertical resolution drops by about half. Also, regarding the horizontal direction, in Figure 4, each pitch of the cell is (A+C), (
Since a signal with a 2-bit period called (B + D) is output, (A
The larger the difference between +C) and (B+D), the lower the horizontal resolution. In other words, the conventional single-chip colorization method requires at least three types of color filters to obtain color signals, which sacrifices resolution. Conversely, in order to obtain the same level of resolution as the black-and-white method, the pixel size had to be halved and the number of pixels had to be doubled. [Means for Solving the Problems] A photoelectric conversion device of the present invention is a photoelectric conversion device composed of a plurality of photoelectric conversion elements, in which the photoelectric conversion elements are arranged in a first region with a high aperture ratio (hereinafter referred to as a high aperture region). It is characterized by being formed separately into a second region (hereinafter referred to as a low aperture region) and a second region with a low aperture ratio (hereinafter referred to as a low aperture region). [Function] In the present invention, a high aperture region and a low aperture region where the aperture ratio is reduced due to wiring etc. are formed separately in a photoelectric conversion element, and the high aperture region and the low aperture region are arranged adjacent to each other. By arranging the high aperture region and the low aperture region adjacent to each other, it is possible to obtain a substantially two-row arrangement with - row photoelectric conversion elements, and a unit photoelectric conversion element can be arranged in two rows. Even when different types of color filters are arranged in the high aperture area and the low aperture area of the conversion element,
It becomes possible to output color signals while maintaining the same resolution as the black and white system. [Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1(A) is a filter arrangement diagram of a first embodiment of a photoelectric conversion device of the present invention, and FIG. 1(B) is an explanatory diagram showing the configuration of a photoelectric conversion element. As shown in FIG. 1(A), one pixel serving as a photoelectric conversion element has a high aperture area S1 in the upper half and a low aperture area S8 in the lower half. Alternatively, the upper half is the low aperture region S2, and the lower half is the high aperture region Sl. FIG. 1(B) shows the configuration of the pixels in the first row, in which the upper half is a high aperture region S1 and the lower half is a low aperture region S2. Regarding the arrangement of a 0-color filter in which such pixels are arranged two-dimensionally so that a high aperture region Sl and eight low aperture regions form a checkerboard pattern, Cr (chromium) is placed in the low aperture region 8O. W (white) is placed in the high aperture area S1 located in the lower half of the cell, and Ye (yellow) or Cy (cyan) is placed in the high aperture area S1 located in the upper half of the cell. are arranged alternately vertically and horizontally. Next, the operation as a color sensor will be explained based on FIGS. 1(A) and 1(B). The reading method is the same as before, reading two lines at the same time, but
The signal synthesis method is as follows. Now, when the first and second rows are read out, the luminance signal is the W output value in the first row, the Ye (or Cy) output value in the first row, and the Cy (or Ye) output value in the second row. It is created by the output average value of . In other words, W and 1/2 (Ye
For the 0 color signal whose output is the luminance signal alternately with 10Cy), R=W-Cy, G=Ye+Cy-W, B=W-
It is created by calculating Ye, but W used for color signal generation is the first
The average output value of W in the row and W in the second row, which was not used for the luminance signal, is used. In this way, in simultaneous reading of two rows, the n-th row and the (n+1)-th row, the luminance signal that determines the resolution is W in the n-th row, Ye (Cy) in the n-th row, and Cy in the (n+1)-th row.
(Ye), so compared to the conventional method of placing one color filter in one cell and obtaining a luminance signal by adding two layers of signals, the vertical resolution can be doubled. I can do it. Moreover, w, Y used in this example
e. C and y color filters have good light usage efficiency and can maintain high sensitivity. Also, W=R+G+B, l/2(Ye+Cy)=
R/2+G+B/2 is Atte, w 1/2 (Ye 1 Cy
), the horizontal resolution is also good. FIG. 3 is a partial plan view showing the structure of an example of a photoelectric conversion device using the photoelectric conversion element and filter arrangement of the present invention. In FIG. 3, 1 represents a vertical output line connected to an emitter formed of aluminum, 2 represents a horizontal drive line formed of polysilicon, etc., and 3 represents a pixel isolation region formed by the LOCO3 method. . Since the wiring part does not become a photosensitive area, when the pixel is divided into upper and lower parts, one side becomes a low aperture area.
The pixel arrangement is similar to that of the above embodiment. By applying color filters as already described to each of these parts, a color dual-reactor sensor with twice the vertical resolution of conventional sensors can be realized. FIG. 2(A) is a filter arrangement diagram of a second embodiment of the photoelectric conversion device of the present invention, and FIG. 2(B) is an explanatory diagram showing the configuration of the photoelectric conversion element. The arrangement Ss of the high aperture region SI and the low aperture region and the arrangement relationship of the color filters are the same as in FIG. 1, but the left and right halves of the unit cell are respectively the high aperture region SI and the low aperture region S2. In a sensor like the one shown in FIG. 2, simultaneous three-layer readout is performed. For example, when lines 1, 2, and 3 are read out, the luminance signal is the output average value 1/2 (Y
e+Cy) and the output W of the second row. Since the unit cell is divided into left and right halves, the horizontal resolution can be doubled compared to conventional methods even if the number of pixels is the same. [Effect of the invention J As explained above, according to the photoelectric conversion device of the present invention,
A high aperture region and a low aperture region where the aperture ratio is reduced due to wiring etc. are formed separately in the photoelectric conversion element, and the high aperture region and the low aperture region can be arranged adjacent to each other. If the high aperture region and the low aperture region are arranged adjacent to each other, a substantially two-layer arrangement can be obtained with the - row photoelectric conversion elements, and the high aperture region and the low aperture region of the unit photoelectric conversion element Even when different types of color filters are arranged in the low aperture region, the resolution can be approximately doubled without reducing sensitivity.

[Brief explanation of drawings]

FIG. 1(A) is a filter arrangement diagram of a first embodiment of a photoelectric conversion device of the present invention, and FIG. 1(B) is an explanatory diagram showing the configuration of a photoelectric conversion element. FIG. 2(A) is a filter arrangement diagram of a second embodiment of the photoelectric conversion device of the present invention, and FIG. 2(B) is an explanatory diagram showing the configuration of the photoelectric conversion element. FIG. 3 is a partial plan view showing the structure of an example of a photoelectric conversion device using the photoelectric conversion element and filter arrangement of the present invention. FIG. 4 is an explanatory diagram showing a cell arrangement of a conventional two-dimensional solid-state imaging device. SI: High aperture region, 1: Low aperture region, 1: Vertical output line, : Horizontal drive line, : Pixel isolation region.

Claims (3)

[Claims] (1) A photoelectric conversion device composed of a plurality of photoelectric conversion elements, characterized in that the photoelectric conversion elements are formed separately into a first region with a high aperture ratio and a second region with a low aperture ratio. Photoelectric conversion device. (2) The photoelectric conversion device according to claim 1, wherein the plurality of photoelectric conversion elements are arranged so that the first region and the second region form a checkered pattern. (3) The first region and the second region of the unit photoelectric conversion element
3. The photoelectric conversion device according to claim 1, wherein different types of color filters are arranged in the regions.