SU1083144A1 - Anti-reflection interference coating - Google Patents

Abstract

ENJOYABLE INTERFERENCE COATING for optical elements with a refractive index of 1.45-1.8, consisting of dielectric layers with alternating high and low refractive indices, the layer,. bordering vozdhghom,. made of substances with a low display; body of refraction, about tl and h and y sh e KSRNUY in i EfltJO. - “T1EXCHEANE: KAA YAKLIOTEKA, e with the fact that, in order to reduce the reflection coefficient in the spectral region

Description

X

:with

4 1 I The invention relates to interference coatings for optical components used in optical instrumentation, in particular, in film and photographic equipment. . It is known to have a coating consisting of four layers with alternating high 2.1-2.3 and low 1.38-1.45 refractive indices, whose optical thicknesses are chosen from the ratio 1 1.96, 0.39j 0.19, measured from air, with the thickness of the first layer being 0.2 N, 1. However, this coating can only be used to clear in the visible spectral region (C 400 .... 700 nm) glasses with low refractive indices (hg 1.45 ... 1.62). In order to brighten glasses with high refractive indices (5 1.62 ... 1.8), such a coating is ineffective. The closest technical solution to the present invention is a luminous interference coating for optical elements with a refractive index of 1.45-1.8, consisting of dielectric layers with alternating high and low refractive indices; the layer bordering the air is made of a substance with a low index of crushing 21. A disadvantage of the known coating is the comparative complexity of the design of the seven-layer coating, as well as the insufficiently wide working illumination of the EFY range and, accordingly, the high reflectance in the entire visible spectral region, which limits its application. The purpose of the invention is to reduce the reflection coefficient in the spectral region (0.75-1.25) L ,, and to simplify the design of the coating. This goal is achieved by the fact that in an antireflection interfering coating for optical elements with a refractive index of 1.45-1.8, consisting of dielectric layers with alternating high and low refractive indices, the layer adjacent to air is made of substances with a low Yoka refractor, the coating is made of OE four layers, the optical 42 thickness of which, counting from the air, is chosen from the ratio n (3 0.455x X .Mid 2 3.76 3.76 XX l 4 d4. 0.25 I o where | 1, P2,, And, p; {- are the refractive indices of the layers, (3, (g Ω is the tric thickness of eV; wavelength corresponding to the middle of the bleaching range, and the refractive indices of the layers of the spring pattern P, Pz 1.37-1.39 P2 and 1.94-2.0., Fig. 1 schematically shows the proposed anti-reflection coating; Fig. 2 shows the spectral reflectance measured on an MSFP-2 microspectrograph in Fig. 3 — the spectral characteristics of the coating for the MPS substrate 1.62 for various layers of refractive indices: curve 1 for ns j 1.94, PC 1.38, curve 2 at; front 2.0, Mon -, curve 3 front 1.96, “n 1.39i curve 4 at Pv 1.96, IH 1.37. The anti-interference interference coating consists of a layer of t with a refractive index of A1.37 ... 1.39, layer 2 with a refractive index of 112 ... 2.0, layer 3 of a refractive index L, 1.37. ..1.39. layer 4 with refractive indices. 1,94 ... 2, O, deposited on the illuminated element 5 with the refractive index Ld and layer thicknesses., .. taken from the air, nidt, 0,455x ,, 76 0,, The ld is the wavelength corresponding to the middle of the illuminated range. The coating was made by vacuum coating of resistive tungsten boats using photometric control of the reflection coefficient. After the vacuum cycle, the coatings were heat treated in air at 350 ° C for two hours. The integral coefficient of the residual reflection of the clarified optical components in the spectral region. nm, measured on the EA-101 reflexometer, is given in the table,

I K8 1 LF7 I BF16 G

Glass grade

    III- I "e-eeei I Refractive index 1,5181,578 Integral residual reflection coefficient,%

TFZ 0.30 1.671 1.717 6.32

Of these graphs, FIG. 3 it follows that the spectral characteristic of the coating changes with a slight variation in the refractive index of the layers within the specified limits.

As can be seen from the above characteristics, the antireflection coating effectively reduces the reflection in a wide spectral range for various types of optical glasses used

; In an optical U) building, in particular in film and camera1) e.

In addition, the proposed coating makes it possible to unify the enlightenment technology (the enlightenment of glasses with different refractive indices simultaneously, during one technological process), and also because the coating characteristics are resistant to deviations of the layer parameters, the requirements for maintaining stability are reduced. process parameters

fi7 ...

as

0.6

0, tf

0

0.5

0.6

0.7 Cpu & .d

Claims (1)

BRIGHTNING INTERFERENCE COATING for optical elements with a refractive index of 1.45-1.8, consisting of dielectric layers with alternating high and low refractive indices, the layer adjacent to the air. made of a substance with a low refractive index, characterized in that, in order to reduce the reflection coefficient in the spectral region (0.75-1.25)%, and to simplify the design, the coating is made of four layers, the optical thicknesses of which, counting from air selected from the ratio P, <ί ₄ = 0.455 η-jd · 2 ⁼ 3.76 · Μ ₃ ό ₃ ⁼ = 3.76 · = 0.25%, where the refractive indices of the layers; , d ₂ ι ^ Λ '^ 4 ~ the geometric thicknesses of the layers; - the wavelength corresponding to the middle of the pro _β brightened range S on, while the refractive indices of the layers are equal P <= P ₃ = 1.37-1.39, P _g = P ₄ = 1.94-2.0. n „1083144