Design method of baffle for controlling distribution of film thickness of planar optical element in film coating planetary system

Abstract

The invention provides a design method of a baffle for controlling distribution of film thickness of a planar optical element in a film coating planetary system. In a vacuum film coating process, the film material is delivered in a vacuum environment through an evaporating mode or a splashing mode, and forms a film with non-uniform thickness distribution on the surface of a planar optical element. Models are respectively established for really reflecting the distribution of the thickness of film deposited on the planar optical element in a planetary system of a vacuum film coating machine under the condition that a baffle is not used and the baffle is not used for correcting. The evaporating or splashing property of the film material in the vacuum film coating process is determined according to the film thickness distribution model under the condition that the baffle is not used, and then the distribution of the thickness of the film on the planar optical element in the planetary system of the vacuum film coating machine is simulated based on a film thickness distribution model theory in the presence of the correcting of the baffle. And finally the baffle design is optimized through a computer until the distribution of the thickness of the film on the planar optical element subject to the baffle correcting in the planetary system of the vacuum film coating machine meets the design requirement, so that the optimal baffle design is obtained. The design method can be applied to precisely controlling the distribution of the thickness of the film on the planar optical element.

Description

technical field [0001] The invention relates to the field of preparation of optical thin film elements, in particular to a baffle design method for controlling the film thickness distribution of planar optical elements in a coating planetary system. Background technique [0002] With the development of science and technology, the design of optical system is becoming more and more sophisticated. In order to meet the performance index of the optical system, the number of planar optical components used in the optical system is not only increasing, but also the size is getting larger and larger. It is usually necessary to plate a specially designed film on the surface of the planar optical element to improve the performance of the planar optical element to meet the performance requirements of the optical system. The current technologies for preparing thin films on planar optical components can be mainly divided into physical vapor deposition (PVD) technology and chemical vapor ...

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Problems solved by technology

Although the single-axis gyro rotation system (F.L.Wang, R.Crocker, and R.Faber, "Large-area Uniformity in Evaporation Coating through a New Form of Substrate Motion," OSA, (2010)) and suitable for ion beam sputtering coating Process dual-drive planetary rotation system (M.Gross, S.Dligatctch, and A.Chtanov, "optimization of coating uniformity in an ion beam sputtering system using a modified planetary rotation method," Appl.Opt.50, C316-C320( 2011)) It is possible to control the film thickness distribution on a large-scale planar optical element without using a baffle, but when using a single-axis gyro rotation system to prepare an optical thin-film element, it is necessary to consider the large swing caused by the planar optical element. The resulting increase in the deposition angle of the film affects the performance of the prepared optical film, as well as issues such as the design of the planar optical element fixture; and the dual-drive planetary rotation system is only possible when the size of the evaporation or sputtering source is large enough. Baffles control film thickness distribution

[0005] As far as the planetary system of the vacuum coating machine is concerned, since the planetary revolution / rotation can be flexibly adjusted, the randomness of the position of any point on the planar optical element is very high, making the connection between any point on the planar optical element and any point on the surface of the evaporation or sputtering source The projection trajectory of the line on the plane where the baffle is placed is very complicated, which makes it difficult to have an analytical solution for the design of the baffle

The traditional baffle design method used to control the film thickness distribution on the planar optical element in the planetary system of the vacuum coating machine is to rely on the coating experience and repeatedly optimize the baffle design through a large number of process experiments to meet the specific film thickness distribution. This design baffle The process is very long, and generally requires at least several or even dozens of process experiments

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