SU966640A1 - Anti-reflection coating - Google Patents

Description

(54) ENHANCING COATING

The invention relates to optical instrumentation and can be used in optical range finders, spectral instruments, laser technology, and the like.

An anti-reflection coating is known that contains a substrate with a multilayer interference system that provides a reflection coefficient of 5% in a given spectral region C 1.

However, such coatings cannot be used to obtain a low reflectance, 15% at three predetermined wavelengths A-, Aj. and D, in addition, the practical implementation of such coatings is difficult due to the presence of layers of 3-4 substances with different refractive indices.

An antireflection coating for optical elements with a refractive index of 1.50-1.65 is known, which contains a substrate with a multilayer interference system located on it, alternating with high p and low pc with refractive indices of layers (.2).

The disadvantage of this coating is the impossibility of its use.

at three wavelengths with the achievement of a high transmission coefficient, as well as the presence of a large number of non-equal-thickness layers, which significantly complicates the coating process, since it is very sensitive to errors in the parameters of the layers. In addition, a large

| Q, the number of layers leads to a decrease in the thermal, mechanical and radiation strength of antireflection coatings. The purpose of the invention is to provide a reflection coefficient of the antireflection coating R 0.0015 at three wavelengths, L 2., wherein L. sl, 2. a 1.5, 5. and simplifying the coating design by reducing the number of layers.

This goal is achieved by

20 that in an antireflection coating the interference system is made of seven layers, the optical thicknesses of which, counting from the substrate, are equal; (0.05-0.07) Ho; (0.03-0.4) -0 (0.2525 0.35) ko; (o, 05-0.08) Ho; (0.050, 08) Ho; (, 0.39-0.46) Ho; (0.20, 0.25) Ho; where X0.32CA + + + Xi,), and, adjacent to the substrate, has a low rate

30 refracted.

The refractive indices have values njj 1.35-1.47, PA 1.85-2.2 .®

Figure 1 shows the proposed enlightened km its coverage.

The coating contains a substrate 1 and an interference system 2 consisting of seven layers (a layer with a high

In the table, media O and 8 are understood to mean a substrate with a refractive index π and a framing medium.

The presented spectral characteristics expose the effectiveness of the proposed anti-reflection coating.

The proposed construction of the antireflection coating may be accepted in many optical devices, where antireflection coatings with low reflectance are required. At several (in particular, at three) wavelengths and a relatively simple design.

Claims (2)

1. The translucent coating for optical elements with 1.50-1.65, with the refraction index fl burning substrate with a multilayer interference system located on it of alternating high p and low pc refractive indices of layers, characterized by refractive index shaded). . Figure 2 shows the spectral dependence of the reflection coefficient, R on L / Lo (L is the radiation wavelength) for the two proposed seven-layer coatings. . Coating parameters are listed in the table. By the fact that, in order to provide the reflection coefficient R 0.0015 at three wavelengths D, L, L, - L - Av a 1, $ 3.5, and to simplify the design of the coating, the interference system is made of seven layers, the optical whose thicknesses, counting from the substrate, are (0.05 0.07) Ho / (003-0.04) Lo (0.25-035) Xo. (005-0.08) Lo, (0.380, 46) -0 g (p, 20-0.25; Lo, where To 0.32 (L. + X-. + Lz), with the layer adjacent to the substrate, has a low refractive index. 2. The coating according to claim 1, about t l and that the refractive index is important  1.35-1.47, pd 1.85-2.2. Sources of information taken into account in the examination 1. Physics of that. Films. Ed. G. Kassa and R.E. Tuna, T. 2, 1967, with. 186. 2. USSR author's certificate No. 718819, class, G 02 B 5 / 28,25.09.78 (prototype).