Design of Double Telecentric Lens Using Machine Vision System

This study presents a design idea for a double telecentric lens for machine vision systems to meet the industry requirements for the on-line inspection of machine vision. First, according to the design index of the system, a suitable initial structure is determined, and based on the imaging principle and aberration analysis method of the double telecentric lens, the aberration of the lens is then optimized repeatedly using the optical design software Zemax. Finally, a double telecentric lens with high resolution, low distortion, and small telecentricity is obtained. The lens system consists of 10 refraction lenses with an operating wavelength range 400–700 nm, a working object distance of 100 mm, distortion of less than 0.07%, maximum telecentricity of 0.06°, and modulation transfer function value greater than 0.5 at a Nyquist frequency of 77 lp/mm. The aberration correction is good and meets the design requirements of the system.