JPS62111204A - Color separating filter - Google Patents

Abstract

PURPOSE:To obtain the titled filter having a good color reproducibility and color balance by composing the 1st and the 2nd lines of a color constitution of the repetition of magenta and green and the 3rd and the 4th lines of a color constitution of the repetition of green and yellow respectively, and by forming the green with overlapping cyan and yellow and by forming the blue color with overlapping magenta and cyan respectively. CONSTITUTION:The titled filter is composed of the repetition of the four lines using the 3 kinds of the coloring matters comprising magenta, cyan and yellow, and the 1st and 2nd lines of said filter are composed of the repetition of magenta Mg. and green G, and the 3rd and the 4th lines are composed of the repetition of yellow Ye and blue B respectively. Thus, the green is formed by overlapping cyan and yellow and the blue is formed by overlapping cyan and magenta. As a video signal, luminance signals Yn [(n) line] and Y(n+1) (n+1 line) of the 1st and the 2nd fields are the same to each other, and are Yn=Mg+G, and Y(n+1)=B+Ye, respectively. The spectacle characteristics of each colors are adjusted in such a way that the shading of the line is quiet in a visible range (a wavelength of 400-700nm), whereby the shading of the line becomes quiet, and the balance of colors are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a color separation filter (hereinafter abbreviated as color filter) that can be used in a single-plate solid-state color camera.

Conventional technology Solid-state color cameras, which have entered the practical stage in recent years, have excellent characteristics such as long life, low power consumption, and high reliability, and are attracting attention in various fields.However, the demand for solid-state color cameras will increase in the future. In order to increase the image quality, it is necessary to improve image quality by increasing the number of pixels, increasing sensitivity, and increasing color S/N, as well as reducing size and cost.

The above improvements involve improving the image sensor itself.

In addition to improvements to the nine circuits of electronic components used in the camera center and front, there are also improvements to the colorization method, and improvements in the colorization method play a particularly large role in achieving high sensitivity and high color S/N.

A color filter that uses complementary color pigments of magenta (Mq), cyan (Cy), and yellow (ye) has been proposed as a color filter with high sensitivity, high color S/N, and reduced line shading. . Its basic configuration is shown in FIG. This color filter consists of four repeating rows, the first and second rows are magenta,
Repeating green (G), the third and fourth rows are cyan and red (
R) is repeated, and in order to reduce line shading, green is created by overlapping cyan and yellow, and red is created by overlapping magenta and yellow. In FIG. 4, the broken lines indicate the range of each light-sensitive detail of the corresponding image sensor.

The image sensor equipped with this color filter reads out signals in 7-frame accumulation mode. Therefore, from the n rows of the first field, the luminance signals Yn and one color difference signal Cn can be obtained as follows.

Yn = Mg −G, Cn = Mg −G Still, from the n+1 row, the luminance signal Yn+1. Another color difference signal Cn-1-1 can be obtained.

Yn+1=Cy+R, Cn+1=Cy-R, that is, a luminance signal and two color difference signals can be obtained.

Yn=Mg+G (Cy+R) Cn=Mg-G, Cn-1-1=Cy-R
The above results can be similarly obtained in the second field.

Problems to be Solved by the Invention However, since the above color difference signals are Mq-G and ay-R, the color reproducibility of magenta and red systems and green and cyan systems is good, but the color reproducibility of yellow and blue systems is poor. is not good. The reason for this will be outlined using color vectors. FIG. 6 is a color vector chart, and from the color difference signals described above, it is possible to reproduce a color in which the color on the line connecting magenta and green and the color on the line connecting cyan and red are vector-synthesized (indicated by diagonal lines).

Ideally, the intersection angle of the two color difference axes should be close to 90°.
'The better the color balance is, but in this case the color difference axis Mq-
The intersection angle between the G axis and the R-cy axis is as narrow as 43°. Therefore, as can be seen from the shaded area, it can be seen that the color reproducibility in the yellow and blue directions is worse than that in the magenta and walking directions.

Therefore, in order to bring the intersection angle of the two color difference axes closer to 900, the color separation between magenta and red (or the color separation between cyan and green) must be
must be made larger. In order to increase the degree of color separation between magenta and red, consider, for example, making red closer to yellow. Red is made of Mgxye, so in order to make R(=Mgxye)→ye, Mq must be close to transparent.
The color tone of magenta and red will be greatly degraded.

As described above, it has not been possible to obtain good color reproducibility and two-color balance simply by changing the spectral characteristics of conventional color filters.

In view of the above-mentioned drawbacks, the present invention provides a line shade reduction color filter that uses complementary color pigments and has good color reproducibility and two-color balance.

Means for Solving the Problems In order to solve the above problems, the color filter of the present invention has four methods.
A color composition consisting of repeating rows, the first row.

The second row consists of repetitions of magenta and green, the third and fourth lines consist of repetitions of yellow and blue (B), the previous record is made by superimposing cyan and the yellow, and the previous record (B) ) is created by superimposing the magenta and the cyan.

Function: With this configuration, it is possible to obtain color output signals Mq-G and ye-B that can reduce line shading, and the intersection angle of the two color difference axes is closer to 90', resulting in good color reproducibility. The shape has a well-balanced color.

EXAMPLE An example of the present invention will be described below. FIG. 1 is a basic configuration diagram of a color filter in an embodiment of the present invention. In this color filter, magenta.

It consists of repeating four lines using three dyes, cyan and yellow, and the first and second lines are maze/green (Mq) and green (G), and the third and fourth lines are yellow (ye). ), consisting of repeating blue (B). Here green is cyan.

Yellow is created by overlapping, and blue is created by overlapping cyan and magenta. In this case, the luminance signal Yn is used as the video signal.
(n line), Yn+1 (n+1 line)
is the same for the first and second fields, and Y n =
Mg −1−G Y n+1 = B + y s , and the spectral characteristics of each color are in the visible region (wavelengths 400 to 70
0nm) and is designed so that line shading is inconspicuous. That is, it is designed so that there is almost no difference in luminance signal between each line. The contents will be explained below.

Yn Yn+1=(Mq(λ)+Cy(λL ye(λ
))-(Mar(λ)・Cy(λ)+ye(λ))=
(Mq(λ)-ye(λ))(1-Cy(λ))...
(1) Mq(λ) Mq transmittance ye(
λ): transmittance Cy(λ
): Cy ttFigure 2 shows the spectral characteristics of magenta, yellow, and cyan.

In equation (1), the wavelength is set to 40 so that Yn Yn+1K0.
From 0 to 560 nm, the cyan transmittance is 90% or more,
Color filters are manufactured so that the transmittance of magenta and yellow is almost equal in the wavelength range of 660 to 700 nm. At a wavelength of 400 to 660 nm, the formula (1) is expressed as follows. Therefore, at a wavelength of 400 to 700 nm, Yn-Yn
+1 Ki Q.

For the above reasons, line shading is hardly noticeable and color reproducibility is improved compared to conventional color filters. The reason for this is that in the case of a true color filter, the first field,
In the second field, the color difference signal On = Mq −G,
Cn-1-1=ye-B can be obtained, and the intersection angle of both color difference axes (Mq-G axis, ye-B axis) is larger than that of conventional color filters. Figure 3 shows a color vector diagram, from which it can be seen that the intersection angle between the Mq-G axis and the ye-B axis is 7.
It is 4°. However, since the spectral characteristics of each color are changed in order to reduce the line shading, the actual intersection angle of both color difference axes is slightly less than 74°, but it is considerably larger than the conventional one.

As described above, according to this embodiment, the color configuration consists of four repeated rows, and the first and second rows are magenta.

The third and fourth rows consist of repetitions of yellow and blue, and the previous record is made by superimposing cyan and the yellow, and the blue is made by superimposing the magenta and the cyan. By using the created color separation filter, line shading is almost inconspicuous, and in terms of color reproducibility, the balance of each color is better than with conventional color filters.

Effects of the Invention As described above, the present invention has a color configuration consisting of four repeated lines, the first and second lines consisting of repeating magenta and green.
The third and fourth rows are yellow and blue repeated, and the previous recording was made by superimposing cyan and yellow, and the blue was made by superimposing magenta and cyan. Line shading is less noticeable, color reproducibility improves the balance of each color, and this has great practical effects.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of a color filter according to an embodiment of the present invention, FIG. 2 is a spectral characteristic diagram of a color filter according to an embodiment of the present invention, and FIG. 3 is a color diagram of a color filter according to an embodiment of the present invention. Color vector diagram when color is reproduced using a filter, 4th
This figure is a basic configuration diagram of a conventional color filter, and FIG. 5 is a color vector diagram when colors are reproduced using the conventional color filter. Name of agent: Patent attorney Toshio Nakao and 1 other person @1
figure

Claims (1)

[Claims] The color composition consists of four repeating rows; the first and second rows are magenta and green, and the third and fourth rows are yellow,
1. A color separation filter consisting of repeating blue, characterized in that the previous record is made by superimposing cyan and yellow, and the blue is made by superimposing magenta and cyan.