Fast steering mirror (FSM) is an optical device commonly used in aviation. It is usually applied in the field of optical pointing, image motion compensation and stable tracking. In FSM, the material used in the mirror is usually silicon carbide or mono-crystalline silicon, which exhibits light, small size, and high optical surface accuracy. In the preparation process, bonding is the key step. The curing process of the adhesive layer usually affects the surface accuracy.

In a study published in Optics Express, a research group led by Prof. XU Yongsen from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) proposed a simplified design method for mirror bonding.

In the traditional manufacturing process of mirrors, the mirror bonding starts after the modification is completed. Optical processing is also required after bonding. This not only increases the preparation time of the mirror, but also has the hidden danger of the separation of the mirror and the optical mount if the optical processing fails.

In some special application areas, the high temperature of the mirror coating will affect the adhesive layer or even fail. At this time, the mirror bonding process is required after the mirror is coated. In order to achieve stable bonding of the mirror, it is necessary to analyze the internal mechanism of the bonding process that affects the accuracy of the mirror surface.

During the curing process, the parameters of the adhesive layer are constantly changing. Therefore, in the bonding process, it is difficult to conduct a theoretical analysis of the adhesive layer. In our study, the unit force method is used to determine the stiffness ratio of the bonding positions of the mirror and the optical mount, thereby avoiding the analysis of the bonding layer. By selecting a reasonable stiffness ratio, the effect of the curing shrinkage stress of the adhesive layer on the change of the surface shape can be reduced.

Based on the above design principles, a mirror made of SiC material was prepared. The test results showed that the surface accuracy of the mirror can meet the optical index requirements. At the same time, it has a good stability in high and low temperature environments. This study provides an analysis method for the adhesion of mirrors and a way of thinking for the rapid manufacturing of the mirror.