Optical system design and stray light analysis on TV camera of vehicle electro-optical system

A dual-field TV camera was designed, which can realize target tracking in narrow field，and target capturing and observing in wide field. Both of the transfer modulation functions(MTFs) of the optical systems of the two field of views(FOVs) are more than 0.6 at 50 lp/mm frequency, the spot diameters are both smaller than the pixel size of 5.5 μm, and the distortions are less than 0.1%. The two FOVs share a common planar array CCD imaging device. And the light can be split through a prism. Considerting the ghost images due to the stray lights generated by the reflecting on the prism surfaces,the LightTools software was utilized to simulate and analyze the stray lights . The simulation indicates that when the half angle of field is between 5.7°~7.6° in wide field, and 2.6°~3.5° in narrow field，the incidences can be reflected by the down surface of the prism; when the half angle of field is between -2.7°~-3.5° in narrow field，the incidences can be reflected by the back surface of the prism. Then they can be focused on the image surface to form the ghost images and stray lights. The method of eliminating stray light in the rear of the split prism is adopted to suppress stray light. The simulation results show that the simulation analysis is correct，and the resolution proposed to suppress the stray lights can be proved to be valid.