Optical system design of dual band vehicle backing fisheye lens

According to the use requirements of vehicle backing lens, design a dual band vehicle fisheye lens based on the principle of "non similar" imaging. This system works in the wavelength range of 480-850nm, with dual band imaging of visible light and near-infrared light, which can realize day and night high definition imaging. The f-number is 1.8, the field angle is 1800 , the focal length is 1mm, and the total optical length is 7.76mm. It has the characteristics of large relative aperture, large field angle and miniaturization. The system adopts 7 groups of 9 pieces anti long distance structure, without special glass and aspheric surface, which greatly reduces the complexity of the system and the manufacturing cost. Use the optical design software Zemax to design its optical system. 1/3 inch CCD is selected as the detector. When the Nyquist frequency is 120lp/mm, the meridional modulation transfer function curve and the sagittal modulation transfer function curve of each field of view are more than 0.5, close to the diffraction limit, and the imaging quality is good. The field curvature of the whole field is less than 1 mm, the relative distortion is less than 25%, and the relative illumination is about 95%. It can meet the use requirements of vehicle backing lens, and can provide all-round driving assistance for drivers.