JPS6040001B2 - trimming filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a trimming filter having comb-shaped transmission characteristics in the visible range.

Conventionally, in frequency-separated single-tube color television cameras, the dye used in the stripe filter has a characteristic in which the transmittance of blue (differently, green (G) and red (R)) overlaps each other in their respective peripheral wavelength regions. Because of this, it is not possible to strictly separate the incident light into blue, green, and red. That is, even light that has passed through the green region of the stripe filter contains a slight light velocity component in the blue or red region, so color reproducibility cannot necessarily be said to be good. A previous paper that tried to improve color reproducibility by layering a trimming filter with a color separation stripe filter was ``Optical System of a Single-Tube Color Film Camera,'' Television, No. 2 Yuka, No. 1, 1972. .

This relates to the color reproducibility of color films, and in particular, a trimming filter has been disclosed that makes the brightness in the edge region have a characteristic close to that of a line spectrum. The shape of this trimming filter is as follows, assuming that the input o is the design wavelength.
It is formed by constricting both sides of a layer having an optical thickness with school caps. As described above, conventional trimming filters are ideally close to the line spectrum, and the transmitting region is also in the edge wavelength band.
On the other hand, trimming filters for normal color photography need to have a sufficiently wide transmission band in order to transmit enough light in each wavelength band (R, G, B) in terms of light quantity. .

Also, a filter is required that can efficiently separate the light beams of each wavelength band using a single filter. An object of the present invention is to provide a trimming filter having characteristics suitable for such requirements.

In the trimming filter according to the present invention, the optical film thickness is reduced by narrowing the layer down to just one layer, and the optical film thickness on both sides is poor.

said Ashiiri. The above objective is achieved by providing a thin film group consisting of alternating layers of. Note that ^o is the design wavelength (reference wavelength). FIG. 1 is a diagram showing the film structure of an embodiment of the trimming filter of the present invention, with the optical film thicknesses n, d, in order from the substrate 10 side.

The first layer 11.n phantom 2 is ≧in. The second layer, 2, ratio 4 is poisonous ^〇, and the third layer 13, n4d4 is intruded. 4th layer 14, 5th layer 15 with Takumi Mogaashi 0, 6th layer 16 with Himoga≧^0, n
The seventh layer 17 with 0 reeds 7d7 is sequentially laminated. However, ^o is the reference wavelength. Like this, the fourth layer of this science 14
Narrowing the chick layer, the first layer 11, the second layer 12 and the third layer 1
A first thin film group formed of three thin film layers, and a second thin film group formed of a fifth layer 15, a sixth layer 16, and a seventh layer 17 are arranged. In addition, ni is the refractive index of the i-th layer, di'
The geometric thickness of the i-th layer, ns is the refractive index of the substrate, and the ratio is the refractive index of the external medium. FIG. 2 is a diagram showing a transmittance characteristic curve of one embodiment of the trimming filter having the configuration shown in FIG. 1.

Note that the vertical axis represents the transmittance T (%), and the horizontal axis represents the wavelength (n), and the axes of the transmittance characteristic curves shown below are all the same. Data on the film configuration for the characteristic curve shown in FIG. 2 are shown below. Table 1 Standard wavelength bar o = 520 nm As shown in Table 1, Z
A high refractive index layer made of r02 is provided, and a low refractive index layer made of Si02 as a main component is provided as an even numbered layer.

As shown in FIG. 2, the characteristic curve has valleys with transmittance of 65% near marks 43 and 57, and has good transmittance characteristics in other visible regions as well. FIG. 3 shows the film slow growth of another embodiment of the trimming filter of the present invention, in which the optical film thickness n. d. 1st layer 21 with 0 Tsumairi, 2nd layer 22 with Yamamo main entry 0, 3rd layer 23 with ngen 3 capture 0, 4th layer 24 with Kokoga Gaku, Takumi d5*. The 5th layer 26・~6th layer 26・n7d7 with Q≧^0 is poison ^
It consists of the seventh layer 27 of o. However, this is the reference wavelength. ~,m
, di, ni' are the same as in FIG. 1, so their explanation will be omitted.

The trimming filter shown in FIG. 3 includes a first layer film group formed by the first layer, second layer, and third layer, and a second layer film group formed by the fifth layer, sixth layer, and seventh layer. It has a structure that narrows the fourth layer. FIG. 4 is a diagram showing a transmittance characteristic curve of an example of the trimming filter having the configuration shown in FIG. 3, and Table 2 shows the data.

Table 2 Reference Wavelength E = 520 nm As shown in Table 2, the odd-numbered layers from the substrate are made of Zr02, which is a material with a high refractive index, and the second and sixth layers are made of Si02. The fourth layer is made of a low refractive index material mainly composed of MgF2, which is a low refractive index material.
A layer consisting of the following is arranged.

As shown in FIG. 4, a trimming filter having valleys with a transmittance of approximately 70% near the 47 separation and 57 addition, and good transmittance in the rest of the visible region can be obtained. FIG. 5 is a diagram showing a transmittance characteristic curve of an embodiment of the trimming filter according to the present invention. The membrane structure is the same as that shown in FIG. 1, but compared to the embodiment shown in FIG. The difference is that a layer with an intermediate refractive index is applied to the first thin film group and the second thin film group instead of a layer with a low refractive index.

Table 3 shows data for the characteristic curve shown in FIG.
Table 3 Reference wavelength o = 520 nm As shown in Table 3, the odd-numbered layers from the substrate are made of Zr02, which is a material with a high refractive index, and the second and sixth layers are A layer consisting of peaks 203, which is a material with an intermediate refractive index, is disposed, and a fourth layer is a layer consisting of MgF2, which is a material with a low refractive index.

As shown in FIG. 5, a comb-shaped trimming filter is obtained which has valleys with a transmittance of 55% near the 48-n skin and 575-n skin, and has good transmittance in the other visible regions. FIG. 6 is a diagram showing the transmittance characteristic curve of one embodiment of the trimming filter according to the present invention, in which the membrane composition is the same as that shown in FIG. 3, but compared to the embodiment shown in FIG. For example, the low refractive index of the second thin film group is replaced with a layer having an intermediate refractive index.

Table 4 shows data for the characteristic curve shown in FIG.
Table 4: Reference wavelength entered: o2 520 nm As shown in Table 4, the odd-numbered layers counting from the substrate side include a layer made of Z2, which is a material with a high refractive index;
Here, a low refractive index layer containing Si02 as a main component is arranged, the fourth layer is a low refractive index layer of MgF2, and the sixth layer is a layer with an intermediate refractive index of peaks 203.

As shown in FIG. 6, a comb-shaped trimming filter is obtained which has troughs with a transmittance of 55% near the 47 and 57 tracks and has good transmittance in other visible regions. FIG. 7 is a diagram showing a transmittance characteristic curve of an embodiment of the trimming filter according to the present invention.

The film structure of the characteristic curve shown in FIG. 7 is the same as the film structure shown in FIG. 1, and Table 5 shows the data. Table 5 Reference wavelength input o = 520 nm As shown in Table 5, the odd-numbered layers counting from the substrate side are layers made of Z2, which is a material with a high refractive index, and the even-numbered layers are also made of a material with an intermediate refractive index. A layer of core 203 is disposed.

As is clear from FIG. 7, a comb-shaped trimming filter is obtained which has valleys with a transmittance of 70% near the 47 and 57 edges and has good transmittance in the other visible regions. FIG. 8 is a diagram showing the film structure of another embodiment of the trimming filter according to the present invention, in order from the substrate 30 side, the optical film thickness n.d.・The second layer 32, which also has 0 Yamamo main entry, and the third layer 33, where n phantom 3 has 0 reed entry. 4th layer 34, n5d5 brat^0's 5th layer 36, scolding 4
6th layer 36 with gakiiri 0, n7d7 is 7th layer 37 with tsumairi 0
・The 8th layer 38 whose npu8 is poison^0 and the 9th layer 39 whose rim is Kei^○ are successively laminated. However, ^o is the reference wavelength. The trimming filter shown in FIG.
layer, and a first thin film group formed of the third layer, and a seventh layer and an eighth thin film group.
A configuration in which the optical film thickness formed by the fourth layer, the fifth layer, and the sixth layer is narrowed by the second thin film group formed by the fourth layer, the fifth layer, and the ninth layer is taken. FIG. 9 is a diagram showing a transmittance characteristic curve of an example of a trimming filter having the same antinode configuration as shown in FIG. 8.

Table 6 shows film formation data for the characteristic curve shown in FIG. Table 6 Standard wavelength: 520 nm As shown in Table 6, the odd-numbered layer from the substrate is a layer made of Zr02, which is a material with a high refractive index, and the second layer and the eighth layer are intermediate layers. A layer consisting of peaks 203, which is a material with a high refractive index, is arranged on the fourth layer and a layer whose main component is Si02, which is a material with a low refractive index.

As shown in FIG. 9, a comb-shaped trimming filter having troughs with a transmittance of 50% near the 47 and 57 patterns is obtained. FIG. 10 is a diagram showing a transmittance characteristic curve of an embodiment of the trimming filter according to the present invention, and its antinode configuration is the same as the configuration shown in FIG. 8.

Table 7 shows data for the characteristic curve shown in FIG.
Table 7 Standard wavelength o = 520 nm As shown in Table 7, the first eyebrow third layer counting from the substrate,
The 7th layer and the 9th layer contain Z2, which is a material with a high refractive index.
The fifth layer is A, which is a material with an intermediate refractive index.
The layer consisting of I2Q is the second layer and the eighth layer is a layer mainly composed of Si02 which is a material with a low refractive index, and the fourth layer and the sixth layer are layers which are a material with a low refractive index. A layer of some MgF2 is provided.

As shown in FIG. 10, a trimming filter having troughs with transmittance of 65% near the 47 and 57 rules is obtained. In addition to the above-mentioned embodiments, the first thin film group and the second thin film group
It goes without saying that various cases are possible with respect to the film structure of the thin film group and how to take the refractive index.

Furthermore, the term "low refractive index substance" used in this application refers to a substance with a refractive index of less than 1.5, and the term "intermediate refractive index substance" refers to a substance with a refractive index of less than 1.5.
．． A substance with a refractive index of 5 or more and less than 1.8 or a substance with a high refractive index refers to a substance with a refractive index of 1.8 or more. Therefore, in addition to the materials shown in the above examples, various known materials can be used. As described above, the trimming filter according to the present application can satisfactorily separate the red, edge color, and blue wavelength bands with a simple configuration, and can satisfactorily transmit light in the center band of each wavelength band. It has outstanding characteristics.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the membrane structure of a trimming filter according to the present invention, FIG. 2 is a diagram showing transmittance characteristics of an example of the trimming filter having the purulent structure shown in FIG. 1, and FIG. The figure shows another embodiment of the membrane structure of the trimming filter according to the present invention, and FIGS. 4, 5, 6, and 7 each show a trimming filter having the membrane structure shown in FIG. 3. Diagram showing the transmittance characteristic curve of one example, No. 8
The figure shows another example of the membrane configuration of the trimming filter according to the present invention, and FIGS. 9 and 10 each show the transmittance characteristics of an example of the trimming filter having the membrane configuration shown in FIG. Figure shown. ns...Refractive index of the substrate, ni...Refractive index of the i-th layer, di... Geometric thickness of the i-th layer, no
...Refractive index of external medium, T ... Transmittance, Input ... Wavelength. *Illustrated illustration of Leopard 8 Illustration of Spear 4 Illustration of Hair et al. Leopard illustration ▽Illustration? Diagram l0 diagram

Claims (1)

[Claims] 1 If the reference wavelength is λ_0, one or more layers with an optical thickness of (λ_0)/4 are narrowed down, and on both sides there is a thin film group consisting of alternating layers with an optical thickness of 2/4λ_0 and 4/4λ_0. A trimming filter characterized by