JPS5942283B2 - color separation stripe filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color separation stripe filter suitable for a frequency separation type color imaging device.

Conventionally, the spectral transmission characteristics of a separation stripe filter used in a color imaging device are such that it is impossible to obtain 100% transmission characteristics in a light transmission wavelength region, which causes color mixture of color components. Various methods have been proposed to eliminate this problem, but the main ones are an ND filter that lowers the transmittance between the separation stripe filters, a complementary color filter or a colored layer that is a complementary color, and a method that equalizes the transmittance. One method is to cover the entire area with an ND filter and a complementary color colored layer to make it planar, and to make the transmittance equal due to the difference in thickness between the filter part and the transparent part. However, in these methods, if an ND filter is used, the overall transmittance decreases, and even if a complementary colored layer is used, the manufacturing method becomes complicated and the characteristics are unstable. The present invention has been made in view of the above points, and its object is to provide a color separation stripe filter with stable characteristics and no color mixture by a simple manufacturing method. The present invention will be explained in detail below with reference to Examples.

Fig. 1 shows an embodiment of the present invention, and shows a yellow stripe filter for a two-tube frequency separation type color imaging device using a semiconductor vapor-deposited film, which has rarely been used due to insufficient transmittance. It consists of 1 is a transparent substrate made of glass (refractive index ns is 1.6), 3 is a color separation stripe filter made of a ZnTe vapor deposited film (refractive index nF for red light).
is 3.5), and 2 is TiO2 with a refractive index nT of 2.3.
It is a transparent thin film layer that can be formed by vapor deposition to a thickness of 0.00 mm,
When the refractive indexes N8, nF, and nT are in the filter transmission wavelength region, the relationship N8 x NT < NF is established. The transmission characteristics of each part at this time are shown in Figure 2. The solid line is only for the thin film layer 3 of TlO2. The broken line shows the transmission characteristics of
5° C. for 5 minutes) and processed into stripes to form a stripe filter 3 for color separation.As shown above, the red transmittance of the present invention is insufficient, but the manufacturing process This makes it possible to use a simple semiconductor yellow stripe filter with stable characteristics in a two-tube frequency separation type color imaging device. Figure 3 shows another embodiment of the present invention, which is different from the above embodiment. Similarly, a Ti film with a refractive index of 2.3 is placed on top of a transparent substrate 1 made of 0 glass, which constitutes the filter section of a two-tube frequency type color imaging device with a built-in yellow stripe filter using a semiconductor vapor deposited film.
O2 and SlO2 with a refractive index of 1.48 are each
60λ)-SlO2(1150λ)-TiO2(760
The light-transmitting thin film layer 2 having the three-layer structure of A) is formed, and ZnTe is further deposited on the light-transmitting thin film layer 2 to a thickness of 8000A, and then heat-treated to form the color separation stripe filter 3. After this heat treatment, a transparent dielectric material 4 made of the same glass as the transparent substrate 1 is coated and smoothed by sputtering.The solid line in FIG. 4 shows the transmission characteristics at that time. Due to the transmission characteristics of the three-layer structure of the filter material of the color separation stripe filter 3, the wavelength-dependent equivalent refractive index is about 1.6 in the blue light region and about 3.0 in the red light region.
It is 2.

The transmittance in the red light region is 65%, but if a photoconductive film with high red sensitivity is used, it is practical even if the transmittance of red light is 65%.In this case, the refractive index N8 of the transparent substrate 1, the color Refractive index NF of stripe filter 3 for decomposition, transparent thin film layer 2
and the refractive index N of the transparent dielectric 4. The relationship is constructed as follows: o Also, as is clear from optical theory, similar results can be obtained when N8>NT>NF and NT<NO. However, as is clear from optical theory, a multilayer interference filter can also be treated as a single layer with a uniform equivalent refractive index having wavelength dependence or a non-uniform equivalent refractive index.

Therefore, even if the color separation stripe filter 3 made of the ZnTe vapor-deposited film is a multilayer interference filter, the results will be the same as long as the above conditions are satisfied. Alternatively, by adding several layers of thin films by vapor deposition, it is possible to provide a color separation stripe filter with good color separation without color mixture.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a color separation stripe filter used in a two-tube frequency separation system according to an embodiment of the present invention, Fig. 2 is a spectral transmission characteristic diagram of the same as above, and Fig. 3 is another embodiment of the present invention. 4 is a spectral transmission characteristic diagram of the same as above, 1 is a transparent substrate, 2 is a transparent thin film layer, and 3 is a transparent thin film layer. The color separation stripe filter 4 is a transparent dielectric material.

Claims (1)

[Scope of Claims] 1. Between a light-transmitting substrate and a color separation stripe filter formed on the light-transmitting substrate, there is a single layer having a transmission characteristic that has a complementary color relationship with the filter due to light interference. Alternatively, a multi-layered transparent thin film layer is interposed, and the refractive index n_S of the transparent substrate and the refractive index n of the color separation stripe filter are
A color separation stripe filter characterized in that _F and the refractive index n_T of the light-transmitting thin film layer are configured to satisfy the relationship n_S<n_T<n_F in the filter light transmission wavelength region. 2. Between the light-transmitting substrate and the color separation stripe filter formed on the light-transmitting substrate, a light-transmitting layer having a single-layer or multilayer structure having a transmission characteristic that has a complementary color relationship with the filter due to light interference. At the same time, the stripe filter for color separation is covered with a translucent dielectric material having a refractive index n_D to smooth the surface, and the refractive index n_D of the above-mentioned translucent substrate is
S, refractive index n_F of the color separation stripe filter, refractive index n_T of the transparent thin film layer, and refractive index n_ of the transparent dielectric material
A color separation stripe filter characterized in that D is configured to have the relationship n_S<n_T<n_F and n_T>n_D, or the relationship n_S>n_T>n_F and n_T<n_D.