阅读说明：本技术 一种折射率匹配的消偏振膜系 (Refractive index matched depolarized film system ) 是由 任少鹏 赵帅峰 高鹏 金�秀 班超 王忠连 杨文华 胡雯雯 于 2019-11-29 设计创作，主要内容包括：本发明涉及光学薄膜领域,尤其涉及一种折射率匹配的消偏振膜系,是以三种材料的消偏振膜系S|(αHβLγMβLαH)^<Sup>n</Sup>|A为基础,根据折射率匹配原理,通过采用匹配膜堆(aHbLaH)替代原有的γM膜层,从而实现两种材料的设计的基础膜系公式：S|(αHβLaHbLaHβLαH)^<Sup>n</Sup>|A,其中：S为玻璃基底；A为空气；H为高折射率材料；L为低折射率材料；a、b为折射率匹配系数；α、β分别表示不同材料的匹配系数；n为循环次数；H、L光学厚度为λ<Sub>0</Sub>/4。该膜系在满足倾斜入射应用领域的消偏振需求的基础上大幅降低生产工艺的难度。(The invention relates to the field of optical films, in particular to a depolarizing film system with matched refractive index, which is a depolarizing film system S (α H β L gamma M β L α H) ^ made of three materials n Based on the A, according to the refractive index matching principle, the original gamma M film layer is replaced by the matching film stack (aHbLaH), thereby realizing the basic film system formula of the design of the two materials, namely S (α H β LaHbLaH β L α H) ^ n Wherein S is a glass substrate, A is air, H is a high refractive index material, L is a low refractive index material, a and b are refractive index matching coefficients, α and β respectively represent matching coefficients of different materials, n is cycle number, H, L optical thickness is lambda 0 /4. The film system greatly reduces the difficulty of the production process on the basis of meeting the depolarization requirement in the oblique incidence application field.)

1. A refractive index matched depolarizing film system, comprising:

S|(αHβLaHbLaHβLαH)^ⁿ|A

wherein S is a glass substrate, A is air, H is a high refractive index film layer material, L is a low refractive index film layer material, a and b are refractive index matching coefficients, α and β respectively represent matching coefficients of different materials, n is cycle number, H, L optical thickness is lambda₀/4。

Technical Field

The invention relates to the field of optical films, in particular to a depolarizing film system with matched refractive index.

Background

The depolarization film system is mainly used in an interference cut-off filter used obliquely, and has the functions of eliminating polarization separation caused by oblique incidence of a conventional film system and ensuring that the cut-off gradient and the width of a transmission area meet application requirements. The existing depolarization film system cannot give consideration to both depolarization capability and passband width. The chinese patent (CN105242340B) discloses a depolarizing film system composed of three refractive index materials, which has good spectral performance, wherein the intermediate refractive index material is realized by a material proportioning method, the process needs to adopt a co-evaporation technology, the technical difficulty is high, and industrialization cannot be realized.

Disclosure of Invention

The invention aims to provide a depolarizing membrane system based on a refractive index matching method, which adopts two materials with high and low refractive indexes to indirectly obtain a material with an intermediate refractive index by a membrane layer thickness matching method, greatly reduces the process difficulty on the premise of ensuring the spectral performance, and is easy to realize industrialization.

In order to solve the technical problem, the invention is realized as follows:

a refractive index matched depolarizing film system, its structure is:

S|(αHβLaHbLaHβLαH)^ⁿ|A

wherein S is a glass substrate, A is air, H is a high refractive index film layer material, L is a low refractive index film layer material, a and b are refractive index matching coefficients, α and β respectively represent matching coefficients of different materials, n is cycle number, H, L optical thickness is lambda₀/4。

The invention relates to a depolarized film system with matched refractive index, which consists of a basic circulation unit and a refractive index matching unit together:

three-material five-layer circular depolarizing film system S | (α H β L gamma M β L α H) ^ⁿ|A；

M index matching film stack: (ahtlah);

the combined refractive index matching depolarizing film is S | (α H β LaHbLaH β L α H) ^ S | (ⁿ|A

Wherein S is a glass substrate, A is air, H is a high refractive index film layer material, L is a low refractive index film layer material, M is a middle refractive index film layer material, a and b are refractive index matching coefficients, α, β and gamma respectively represent matching coefficients of different materials, n is cycle number, H, L, M optical thickness is lambda₀/4。

The high-refractive-index film layer material is TiO₂、Ta₂O₅、Nb₂O₅、HfO₂Any one of the film layers with low refractive index is made of SiO₂。

The invention can keep the spectral performance unchanged on the basis of reducing a coating material, and optimizes the process route. The conventional coating equipment is mainly designed for two coating materials (double electron guns or double targets), and can realize the coating of various materials in a crucible switching mode, but the number of layers of a film system and the selection of materials are limited to a certain extent, so that the production of the products cannot be realized. The invention has good spectral characteristics in the application of oblique incidence of light rays, and has the advantage of simple process, which comprises the following specific steps:

1. high steepness, such that the wavelength range between the transmission region (T > 90%) and the cut-off region (T < 2%) is less than 10 nm.

2. Wide transmission band, and transmission region (T > 90%) range up to 400 nm. In general design concept, the limit value of the transmission range of the product is 300 nm.

3. Small polarization separation degree, P light and S light in T50% T_PKThe degree of polarization separation is less than 1 nm.

4. The intermediate refractive index material M is formed by matching H, L two materials through physical thickness, the whole film system is realized by only two materials, the process is simple, and the industrialization requirement can be met.

Drawings

The invention is further described with reference to the following figures and detailed description. The scope of the invention is not limited to the following expressions.

FIG. 1 shows a conventional dichroic mirror depolarizing film system (1.5LH1.5L) ^ⁿDesigning a curve;

FIG. 2 is a design curve of a single-side depolarizing film system based on a band-pass film system of a conventional dichroic mirror;

FIG. 3 is a schematic structural diagram of a depolarizing film system matched with three materials of Chinese patent (CN 105242340B);

FIG. 4 is a schematic view of a membrane system according to the present invention;

FIG. 5 is a film system design curve of the present invention;

FIG. 6 is a partial enlarged view of the design curve of the present invention.

Detailed Description

As shown in FIG. 4, the index-matching depolarizing film is a three-material depolarizing film S | (α H β L γ M β L α H) ^ CⁿBased on the A, according to the refractive index matching principle, the original gamma M film layer is replaced by the matching film stack (aHbLaH), thereby realizing the basic film system formula of the design of the two materials, namely S (α H β LaHbLaH β L α H) ^ⁿ|A

Wherein S is a glass substrate, A is air, H is a high refractive index film layer material, L is a low refractive index film layer material, a and b are refractive index matching coefficients, α and β respectively represent matching coefficients of different materials, n is cycle number, H, L optical thickness is lambda₀/4。

The high-refractive-index film layer material is TiO₂、Ta₂O₅、Nb₂O₅、HfO₂Any one of the film layers with low refractive index is made of SiO₂。