In the light of optical-electronic imaging system ,designed a continuous zoom lens with a optical aperture of 60mm and a zoom range of 18-246mm. Summarized the disadvantages of the former zoom lens and a low temperature resistant and high precision structure ,named the special-shaped slide and cam zoom structure is proposed, and carrying out the theoretical analysis and the detailed structural design. Theoretical analysis shows that this kind of structure can make the sliding friction between the cam and the main mirror tube turned into rolling friction ,thus reducing the torque demand.it also helps to eliminate the stuck phenomenon of the cam in low temperature environment .The special-shaped slide frame structure can help eliminate the tilt Angle of the moving mirror group in the zoom process ,thus reducing the variation of optic axis .In the he final test, the zoom time is not longer than 8s in the environment which temperature is only -45°C,and the variation of optic axis is smaller than 0.3milliradian,both meet the target requirement.
For some extreme environment, such as vibration and shock during rocket launching or ultralow temperature in tank of cryogenic propellant, some key technology of the optical measurement device used in liquid oxygen tank of carrier rocket have been researched. In order to obtain a light-weight, high-stiffness and large-heat resistance main board structure for optical measurement device, a thermo-mechanical topology optimization technique is introduced into the main board structure design of optical measurement device for improving the designing quality. Compared with that before the optimization the main board structure reduces weight loses 46.8 percent with the first-order natural frequency above 420 Hz. The numerical results indicate that after adopting the topologic optimization design method, not only the design course is shortened, but also the main board structure weight is effectively reduced, heat resistance is effectively increased and the capability of the main board structure is enhanced. The extreme temperature test results show that the method is effective.
Zoom cam is a pivotal part used for driving every lens group in zoom lens , the design result of cam curve is decisive importance for motion property and system precision as well as system imaging in zoom system, therefore, zoom cam design is an important part of the zoom lens design, a fine cam performance is the basic requirements to reach lens design of image quality goal and optical zoom process. a new method is presented in this article, it adopts the method of piecewise processing to establish several common functions in steep interval so as to make the arc length non-uniform and to segment the arc length equally in the smooth curve. The initial cam curve of an optical system is optimized and analyzed, the results show that when the arc length is divided by the power function, the cam curve can be significantly improved, the pressure angle of the curve can be reduced, and the optimized curve is smooth and without inflection point, which can effectively improve the overall performance of the cam.
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