Study On Computer Aided Alignment For Two Mirror Reflect Optical System

While the optical and mechanical structure of the system has become more complicated,especially the widely use of the off-axis aspheric surface, it is hard to satisfy the requirementof high quality image without the high precise means of optical system alignment. Based onadvanced optical testing technology, modern optical theory and computer analysis technology,computer–aided alignment (CAA) technology has been developed to solve the difficulties ofhigh quality optical system alignment in recent years, which play the key role in the processof system development.The alignment process of an optical system can be more complicated than its originaldesign. For example a misaligned multi-element system will sufer from imaging aberrationsthat vary in a complex way over the field of view. These have been written in terms ofpolynomial expansions in pupil and field space, which are useful for understanding thephenomena, but are difcult to apply. the vector theory is introduced based on the wavefrontaberration theory, and the mathematical model for the relationship among the three-orderwavefront aberration of the system, optical field coordinate and Fringe Zernike coefficients isset up. The misalignment of the component is translated into the shift of corresponding imagefield on the basis of the wavefront aberration characteristic of the system. The aberrationmodel of misalignment component establishes the relationship between the testing result ofwavefront aberration of the system and the misalignment of the component.For the large aperture and long focal length collimator optical system with off-axisoff-axis aspheric surface, The primary mirror is determined to be the alignment referencethrough the tolerance analysis of the optical components in the system. The alignment processand wavefront aberration model with CAA technology are established. The wavefrontaberration models of the paraboloid primary mirror and the system are built, and thecorrectness and veracity of the wavefront aberration model are proved. The simulatingcalculation result for the optical system with CAA technology shows that the model canobtain the misadjustment of the optical component to be aligned accurately, and theapplication of the technology can meet the requirement for the alignment of the opticalsystem.