The Research On Adjustable Focal Calibration Device Of Airborne UV Detection System

With the continuous development of ultraviolet imaging detection system, and its performance will directly affect the operation security of weapons, so which needs to be tested and calibrated. Adjustable focal calibration device of Airborne UV detection system effectively solve the problem of Parallelism calibration of the ultraviolet and visible light optical axis and image quality detection of different object distance.Based on the analysis and comparison of calibration testing equipment both in foreign and domestic countries, this thesis selects the right program and designs Adjustable focus optical system for calibration of UV and visible light optical axis parallelism, focus range is25m～∞. For the problem of most current calibration system cannot focus, a method for calibrating both UV and visible light optical axis parallelism and focusing the part ultraviolet is put forward. At the meanwhile, this thesis designs measured ultraviolet imaging lens system. By analyzing the operating environment and technical indicators of the calibration system is to determine the detailed design parameters of the calibration system. This thesis adopts Cassegrain system as initial structure to design and adds a group of focus and compensation in the traditional Cassegrain system to achieve focus and aberration compensation. Aspheric and diffractive surface is introduced in the system, which effectively improves the image quality of the system.The results of the design show that ultraviolet imaging lens has good image quality, aperture is60mm, the focal length is300mm, and optical total length is287mm. MTF value at the cutoff frequency is701p/mm, center of the field is close to the diffraction limit, the edge of the field of view reaches to0.7or more. Maximum radius of diffuse plaques is5.526, Each view point column chart dispersion spot size is within the size of detector pixel, which just likes that the degree of energy centralism within diffuse spot size20can reach90%. The aperture of UV-visible light with dual-band calibration system is220mm, focal length is1500mm, and total length of optical is1272mm. The entire calibration system consists of two mirrors, four lenses and a half mirror. Design results show that when the transfer function at spatial frequency is601p/mm in the different distance from the ultraviolet band, both the field of view axis and the axis can reach more than0.7, the maximum radius of diffuse plaques is5.872, the energy concentration reaches90%. When he transfer function at spatial frequency is601p/mm in the visible light region, the field of view of the shaft and the outer shaft can reach more than0.55, the maximum radius of diffuse plaques is10.297, the energy concentration can reach90%. The system designed in the research can effectively solves the calibration problems of ultraviolet and visible dual-axis parallelism offset and improves the calibration efficiency of UV and visible dual axis parallelism. Lower optical transfer function values and point spots in the different diffraction are close to the horizon limit meet the design requirements.