Optical Design Of Zoom Projection Lens

With the maturity of CNC machining for the cam curve and proficiency in theory of zoom optical design.The image quality of the zoom system and the stability of image plane are guaranteed.Therefore,the zoom optical system has been more widely used.The zoom projection lens is an important part of the structure of the projector.The different multiples of amplification can be achieved in the case of the same working distance.A zoom projection lens is designed to meet the requirements of different sizes of big rear-projection screen with the same light engine and screen location.Focal length range of the zoom projection lens is 22mm-37 mm,the viewing angle is 46o-75o,F number is 2.8.Since the optical system to be designed should have a big relative aperture,big field of view and small zoom ratio,the concept of zoom system is selected.The positive mechanical compensation configuration was adopted,the proper magnifications of the zoom configuration were chosen and the Gauss roots were derived.The appropriate primal configurations based on each subassembly are chosen.The optimization design is carried out with ZEMAX optical design software,and added proper aspheric surface.The distortion of the zoom system is improved by two,four motion mechanical compensation configuration,and the modulation transfer function(MTF)is used to evaluate the system.The design and assessment results indicate that the optical structure and image quality of the zoom projection lens system meet the design specification.The modulation transfer function is bigger than 0.3 at the spatial frequency of 64 mmlp /,the distortion is less than 1%.