Real-time closed-loop control system for film coating and control method thereof

Abstract

The invention relates to a real-time closed-loop control system for film coating and a control method thereof, belongs to the technical field of optical film coating, and solves the problem of how torealize real-time monitoring and closed-loop compensation of thickness of a film in a film coating process. The real-time closed-loop control system for film coating provided by the invention comprises a probe moving guide rail, a film thickness monitoring probe, a control computing module, a motor driving module, a baffle plate formed by more than one sub baffle plates, a baffle plate supportingrack and a plurality of driving motors, wherein the film thickness monitoring probe measures film thickness information of a sampling point in real time; the probe moving guide rail feeds position information of the film thickness monitoring probe back; the control computing module executes a closed-loop algorithm and compares the difference between the measured thickness of the film and the target thickness to obtain a baffle plate correcting policy; the motor driving module executes the baffle plate correcting policy and sends a moving signal to the driving motor; and the sub baffle plates move under control of the corresponding driving motor to form a corrected shielding line shape, so that closed-loop control of the film thickness is achieved.

Description

technical field [0001] The invention belongs to the technical field of optical coating, and in particular relates to a coating real-time closed-loop control system and a control method thereof, and is especially suitable for coating large-diameter uniform or non-uniform optical films. Background technique [0002] Reaction sintered silicon carbide (RB-SiC) has the advantages of small specific gravity, small thermal expansion coefficient, high thermal shock resistance, high specific stiffness, good thermal conductivity, and high dimensional stability, and is widely used in the primary mirror of large-aperture optical telescopes Material. However, reaction sintered silicon carbide has microscopic composition inhomogeneity, and in optical processing, there will be steps caused by inhomogeneity of polishing material removal characteristics, which restricts the improvement of the surface roughness of the mirror. Mirror surface modification technology effectively solves this prob...

AI Technical Summary

Problems solved by technology

However, in the coating process, with the consumption of film material or target material, the uniformity of film deposition often changes with time, which eventually leads to the deterioration of film uniformity with the prolongation of coating time, especially in the preparation of large-diameter silicon More prominent when modifying layers

[0005] In the prior art, a fixed uniform baffle is used to correct the thickness of the film. Although this method has a certain uniformity correction capability, it cannot compensate for the real-time changes in uniformity caused by the consumption of film materials or targets.

[0006] And in the prior art, there is no method that can accurately prepare non-uniform thin films with specific variation rules

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