JPH01233981A - Color image pickup device - Google Patents

Abstract

PURPOSE:To use a complementary color filter with a size corresponding to a picture element and to facilitate the manufacture of a device by employing a color filter array where the complementary color filters having a characteristic in which red and blue components of two filters are equal to odd and even number of columns are arranged and arranging the two complementary color filters so as to be over lapped equally to a photodetection section. CONSTITUTION:A color filter 8 consists of 4 kinds of Cy, Ye, Mg, G complementary color filters arranged with an equal pitch to that of the picture element 10. Moreover, each set replacing the order of each complementary color filter is arranged alternately in the vertical direction and the 12 color filters are arranged so as to be overlapped to two adjacent photodetection sections (picture element 10) arranged in the vertical direction by a half each. According to the complementary color filter arrangement, the ratio of the R component of the odd number of column and the R component of even order number column is 1:1, equal to each other and the ratio of the B component of odd number columns and the B component of even order columns is 1:1 equal to each other. Moreover, the ratio of the R and B components of the odd and even order number columns is 1:1. Thus, the resolution, sensitivity and color balance in the horizontal direction are ensured and the device is easily manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a single-chip color imaging device that obtains three primary color signals using one imaging device, and particularly relates to an improvement in the arrangement of color filters.

[Prior Art] A solid-state image sensor basically has a photosensitive section consisting of a large number of photodiodes arranged on a plane, and stores signal charges read out from this photosensitive section, and stores the signal charges for one cycle. It is composed of a vertical transfer section that transfers vertically, and a horizontal transfer section (hereinafter, the transfer section will be abbreviated as COD) that transfers the vertically transferred signal charges roughly toward the output end.

In this case, the light receiving sections are arranged regularly corresponding to the pixels, but the configuration of the vertical CCD differs depending on whether the TV scanning system is interlaced or non-interlaced, and even in the same interlaced system, signal charges are There are two modes, field accumulation and frame accumulation, depending on the driving method for accumulation.

FIG. 8 shows the structure of an image sensor adopted in the interlaced system, as well as the principle of field accumulation in FIG. 8(a) and the principle of frame accumulation in FIG. 8(b).

In other words, this interlaced image sensor 1 has a light receiving section (hereinafter abbreviated as PD) 11', 12.13°.
..., 21.22.23. ... are arranged regularly, and one C for every two PDs.
CD31, 32.33. ..., 41.42.43.
...is provided. In the field accumulation mode, as shown in Figure (a), P in field A is
DII, 12 signal is sent to CCD31, PD13.14
The signal of PD12.13 is transferred to CCD32 in the same format, and the signal of PD12.13 is transferred to CCD3 in the B field.
1, the signals of the PDs 14 and 15 are transferred to the CCD 32 in the same format. Therefore, signals of two PDs in different combinations for each field are mixed by one COD and interlaced scanned. In addition, in the frame accumulation mode, as shown in FIG. 3(b), in the A field, the signal of PDll is transferred to the CCD 31, the signal of PD13 is transferred to the CCD 32, and so on in the same format.
In the field, the signal of PD12 is sent to CCD31, PD14
The following signals are transferred to the PD 32 in the same format. Therefore, different PD signals are transferred for each field and interlaced scanning is performed.

FIG. 9 is a diagram explaining the operation of the non-interlaced method, and the image sensor 2 includes light receiving sections 11, 12, 13, .
..., 21.22.23. . . . corresponding to CCD31.32.33. ..., 41.42.43
．． ...is provided. Then, the signal charges of all PDs are transferred to the corresponding COD for each field.

On the other hand, in the operation of the above-described image sensor, only 1q of signals whose imaging width changes depending on the intensity of the brightness and darkness of the light are output, and color information cannot be identified by this alone. Therefore, in order to obtain color signals, it is necessary to either take out the signals in parallel or to take out the signals by multiplexing them in some way.
The most basic methods include a three-plate type, a two-plate type, a single-plate type, and a field sequential type. Each of these methods has its own features, but among these, the single-chip method that is relevant to the present invention is a method that obtains three primary color signals from one image sensor, and a color filter is attached to each of the pixels arranged two-dimensionally. Color information is obtained in a form in which color information is multiplexed with luminance information. The luminance signal in which color information is multiplexed is separated into a high-resolution luminance signal and three color signals via a separation circuit.

In order to multiplex color information of an imaged object, an optical film called a color filter array (hereinafter simply referred to as a color filter) provided in front of an image sensor is used.

FIGS. 10 to 14 show typical arrangements of conventional color filters of this type. Of these, Figure 10 (
The color filter 3 shown in (a) is a stripe in which primary color filters of R (red), G (green), and B (blue) are arranged in a stripe pattern corresponding to one row of pixels shown in (b) of the same figure. The color filter 4 shown in FIG.
is a mosaic filter in which R2O and B primary color filters are arranged in a checkered pattern corresponding to pixels. Further, the filter 5 shown in FIG. 12 corresponds to one row of pixels Cy (
This is a stripe filter in which complementary color filters of cyan), G (green), and Ye (yellow) are arranged in a stripe pattern, and the filter 6 shown in FIG. This is a mosaic filter, in which complementary color filters are provided in correspondence with each other, and are composed of a stripe-like complementary color filter and a mosaic-like complementary color filter for one row of pixels. The filter 7 shown in FIG. 14 is also a mosaic filter similar to that shown in FIG. 13, or it is one in which complementary color filters forming stripes are arranged in a different order. Incidentally, a Mg (magenta) complementary color filter is also used here.

Regarding the colorization method of so-called single-chip color cameras that obtain color signals using such color filters, see F Matsushita Technical Report JVo1.31No, 1 Feb.
, 1985, so I will omit it here.
The main characteristics required of these color filters are: 1) High resolution.

2) The light utilization rate of the color filter is high.

3) Good reproducibility and good color S/N ratio.

4) Fewer false signals occur.

5) A color filter configuration with easy signal processing.

6) Color filters should be easy to manufacture.

is required.

[Problems to be Solved by the Invention] Among the color filters used in the conventional color imaging device described above, the primary color stripe filter shown in FIG. 10(a) has low horizontal resolution and low sensitivity. Unfortunately, the primary color mosaic filter shown in Fig. 11 has low vertical resolution and poor sensitivity, and the complementary color stripe filter shown in Fig. 12 has good sensitivity, but
As expected, the problem was that the horizontal resolution was low.

In addition, the mosaic filters shown in FIGS. 13 and 14 can improve the resolution and sensitivity, as well as the fact that it is technically difficult to manufacture extremely small filters that are half the size of one pixel. Horizontally (Buru R
There was a problem in that the component ratios of and B were not balanced, resulting in an unnatural boundary between blue and red colors.

The present invention was made in order to solve the above problems, and it is possible to ensure resolution, sensitivity, and horizontal color balance to a degree that can be considered good in conventional devices. The purpose of this invention is to obtain a color imaging device that can be manufactured in a number of ways.

[Means for Solving the Problems] In order to solve the problems of the conventional color imaging device described above, the present invention aims to solve the above-mentioned problems of the conventional color imaging device. Complementary color filters arranged in a mosaic pattern are used as color filters.

That is, according to the first embodiment of the present invention, a solid-state image pickup device has a large number of light-receiving sections arranged two-dimensionally and sequentially transfers signal charges in each light-receiving section to obtain an output signal, and In a color imaging device having a two-dimensional array of color filters disposed on a light-receiving surface side and having the same pitch as the light-receiving section, the color filter transmits blue components in odd-numbered columns and even-numbered columns extending in a vertical direction on a display screen. The complementary color filters are arranged in a mosaic pattern in which the red component is equal to A color imaging device with features is provided. Further, according to a second embodiment of the present invention, there is provided a solid-state image sensor in which a large number of light-receiving parts are arranged two-dimensionally and the signal charge in each light-receiving part is sequentially transferred to obtain an output signal, and a light-receiving surface of the solid-state image sensor. In a color imaging device having color filters disposed on the side, arranged in a two-dimensional array at the same pitch as the light receiving sections, and superimposed on the light receiving sections in one-to-one correspondence with each of the light receiving sections, the color filters are displayed. There is provided a color imaging device characterized by a complementary color filter having a mosaic arrangement in which blue components and red components transmitted in odd and even columns extending in the vertical direction on a screen are equal.

[Function] In both the first and second embodiments of the present invention, good sensitivity is maintained by using complementary color filters, and good resolution is maintained by arranging the complementary color filters in a mosaic pattern. There is.

In the first embodiment, a color filter array is used in which complementary color filters are arranged such that the blue component and the red component when the two are combined are equal in odd-numbered columns and even-numbered columns. By arranging the filters so as to overlap them evenly with respect to the light-receiving section, it is possible to use a complementary color filter of a size corresponding to the pixel, and at the same time ensure ease of manufacture.

In addition, in the second embodiment, by superimposing complementary color filters with characteristics that are a combination of the two complementary color filters in the first embodiment on the light receiving section, it is possible to use complementary color filters with a size corresponding to the pixel. At the same time, ease of production is ensured.

[Embodiment] FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention, in which the color filter 8 includes a large number of light receiving sections arranged vertically and horizontally, that is, Cy arrays arranged at the same pitch as the pixels 10, Ye, M.
It is composed of four types of complementary color filters: g, G.

In this case, CV and Ye form a pair and are adjacent in the horizontal direction,
Similarly, M(] and G form a pair and are adjacent to each other in the horizontal direction.Furthermore, each pair of these complementary color filters in a different order is arranged alternately in the vertical direction, and furthermore, in the vertical direction, As you can see, two adjacent complementary color filters are equally stacked on one pixel.In other words, each of the 12 color filters is stacked on two adjacent light receiving areas (pixel 10) arranged vertically. They are arranged so that they overlap by one-half each.

Figure 2 is a chart showing the proportion of the R (red) component from each pixel behind the components that have passed through the color filter;
The figure is a chart without showing the proportion of the same <8 (blue) component.

As is clear from FIGS. 2 and 3, with the complementary color filter arrangement as shown in FIG. The ratio of the B component of the even numbered column to the B component of the even numbered column is also equal at 1:1. Also, the ratio of the R component to the B component in the odd numbered rows, and the ratio of the R component to the B component in the even numbered rows.
The ratio of each component is 1:1. therefore,
It can be said that the sampling balance of the R and B components is well balanced.

Note that color separation using this color filter is performed as follows.

Here, each signal output of the 4n+1 line, 4n+2 line, 4n+3 line, and 4n line is set to S4n+1. S4n
+2. S4n+3. When S4n is set, the following equation holds true.

Converting these equations into R, G, and B components results in the following equation.

Therefore, the luminance signal component is obtained by extracting the baseband component, and the color signal component is obtained by extracting the modulation component.

Next, FIG. 4 is a block diagram of a second embodiment of the present invention, in which a color filter 9 has a large number of light receiving parts arranged vertically and horizontally, that is, four types of complementary colors arranged at the same pitch as pixels 10. Filters A, B, C, and D form the bottom of the groove, and each complementary color filter is stacked at a position corresponding to each pixel 10. In this case, each of the complementary color filters A, B, C, and D has transmission characteristics as shown in FIG. What we have is used. Specifically, the relative sensitivities of the four color filters A, B, C, and D to the three primary colors B, G, and R are as follows.

Note that the mutual arrangement of complementary color filters A, B, C, and D is as follows.
The filters are not limited to those shown in the figure, and for example, the same color separation as described above is possible using the filters 9A and 9B arranged as shown in FIGS. 6 and 7. , the same characteristics as in FIGS. 13 and 14 showing the conventional example are (q). In the arrangement of FIG. In the configuration shown in FIG. 7, filters C and A are alternately arranged in odd-numbered columns, and filters D and B are alternately arranged in even-numbered columns. Exactly the same effect is produced by reversing the odd-numbered columns and even-numbered columns in the configuration of FIG. 7, respectively.

[Effects of the Invention] As is clear from the above explanation, according to the present invention,
The resolution, sensitivity, and horizontal color balance of a color dynamic image device can all be secured to a level that is considered good with conventional devices, and it also has the excellent effect of being easy to manufacture. It will be done. Furthermore, even if the boundary between blue and red colors is imaged by the color imaging device of the present invention, in which the conventional signal processing circuit can be used as is, the image will be reproduced very naturally.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention, FIGS. 2 and 3 are diagrams for explaining the operation of the same embodiment, and FIG.
The figure is a schematic configuration diagram of the second embodiment of the present invention, FIG. 5 is a spectral behavior diagram of the elements constituting the same embodiment, and FIGS. 6 and 7 are schematic configurations of modified examples of the second embodiment. Figure 8(a),
(b) and FIG. 9 are explanatory diagrams for explaining the configuration and principle of a general image sensor, and FIGS. 10 (a) and (b)
), Fig. 11, Fig. 12, Fig. 13 (a) and (b)
) and FIG. 14 are arrangement diagrams of a filter array used in a conventional color imaging device. 1.2...Image sensor, PD...Light receiving section, 7
, 8.9...Color filter array, CCD...Transfer section, 10...Pixel inventor: Takeshi Sasaki Patent applicant: Victor Japan Co., Ltd.

Claims (2)

[Claims] (1) A solid-state image sensor in which a large number of light-receiving parts are arranged two-dimensionally and obtain an output signal by sequentially transferring signal charges in each light-receiving part; In a color imaging device having a two-dimensional array of color filters with equal pitches, the color filters are arranged in a mosaic pattern in which blue and red components transmitted are equal in odd-numbered columns and even-numbered columns extending vertically on a display screen. 1. A color imaging device, wherein each color filter is arranged so as to overlap by one-half with respect to two adjacent light-receiving sections arranged in the vertical direction. (2) A solid-state image sensor in which a large number of light-receiving parts are arranged two-dimensionally and obtain an output signal by sequentially transferring the signal charge in each light-receiving part; In a color imaging device having color filters arranged in a two-dimensional array with an equal pitch and superimposed on each of the light receiving sections in one-to-one correspondence, the color filters extend in an odd numbered row in the vertical direction on a display screen. 1. A color imaging device characterized by a complementary color filter having a mosaic arrangement in which blue components and red components transmitted in even-numbered columns are equal.