Optical System Design Of 30-300mm Light Weight Zoom Objective Lens

The zoom system has been widely used in various industries.The requirements of the design of zoom system are also different.Due to different uses,some industries not only have requirements for the image quality of the system.There are also some stricter requirements for the weight and volume of the system.All of these are to make the zoom system suitable for more special environments.A light weight zoom optical system with long focal is designed.The focal length is 30mm~300mm.The field of view is from 1.1° to 11.4°and the F number is 3.5.Because of the long focal length of zoom system and the weight should be reduced under the premise of controlling the caliber,after the study of the zoom theory,the design uses positive lens compensation.ZEMAX software is used to design the zoom system.The image quality and weight optimization are carried out simultaneously for the zoom system.Some aspheric surfaces are added to the optimization.It not only simplifies the structure,but also improves the image quality.The materials used in zoom lens are analyzed and compared.Part of the lens material is replaced effectively.At the same time,the relative illumination of the image plane is within the allowable range,and the off-axis light is intercepted appropriately.The effective diameter is reduced as far as possible.The relationship between image quality and weight is balanced.The total weight of the optical system is reduced from 920 g to 648 g.The image quality of the system is good.The modulation transfer function(MTF)of the 0 field of view is more than 0.3 at 120 lp/mm and the modulation transfer function of other field of view is more than 0.2 at 120 lp/mm.The modulation transfer function of all field is more than 0.5 at 40 lp/mm and the distortion is less than 1%.According to the zoom motion equation and programming with MATLAB software,the motion curves reflecting the motion process of the doubling and compensating groups are obtained.The image surface is stable and the focus is smooth in the process of zoom transformation.Finally,the tolerance analysis of the zoom system are carried out.The system has light weight and good image quality at the same time.