Design of a large imaging plane wide-band zoom adapter optical system for endoscopes

This paper presents a design of a large imaging plane wide-band zoom optical system, by analyzing the Gaussian principle of the mechanically compensated zoom system, the initial structural parameters are determined. The optimized system has a zoom range of 18-35.5 mm and distortion is less than 2%. It achieves wide-band parfocality (400-850 nm), meeting the usage requirements for 4 K resolution sensors. The system is designed with a spherical lens, and tolerance analysis indicates its suitability for mass production. Experimental results show that the system achieves a center resolution of 174 lp/mm and 104 lp/mm in the visible spectrum and NIR-I band, respectively, which significantly improves the resolution and sensitivity of the endoscope adapters.