Design And Manufacture Of Vehicle Panoramic Fish-eye Lens

In recent years, with the continuous advancement of science and technology, the development of precision machinery design and processing technology, the widely use of the imaging chip technology and plastic aspheric surface, the development of optical lens have been promoted rapidly. However, the field range that based on normal vision system couldn’t satisfy the needs of people, more and more researchers apply their mind to study and develop fish-eye lens which has large viewing angle. Fish-eye lens have a strong demand in the art photography, traffic monitoring, motion detection, transportation and some other fields. There still more challenging problem on the field of view angle of the fish-eye lens which being used in security monitoring. This paper expands the research of fish-eye lens towards the direction of large viewing angle and high resolution, combining with the demand of security monitoring market.The main purpose of this paper is to study and design a 240 degrees panoramic fish-eye lens and a high resolution vehicle fish-eye lens. Take advantage of technology platform related production equipment in high technology enterprise, the 240 degrees panoramic fish-eye lens can be produced in mass. In this paper, the main research work and conclusion are as follows:(1)This paper introduces the origin and history of the fish-eye lens. Further this paper describes the application of the fish-eye lens in domestic and foreign in related fields and illustrates the significance of studying the theory and reality of the fish-eye lens. At last, this paper analyzes the future development direction of the fish-eye lens in vehicle security monitoring market in the future.(2)This paper expounds the imaging principle of fish-eye lens. Especially this paper analyzes the formula of non-similar imaging principle of the fish-eye lens. This paper describes the design method of the fish-eye lens according to the analysis of the difficulties during the design. Therefore guidance and reference for the subsequent design and research of fish-eye lens have been provided.(3)Through the market survey, the requirements of optical parameters of a 240 ° panoramic fish-eye lens have been confirmed. According to the appropriate initial optical structure from related patents, the suitable initial optical system has been selected and then the optical system has been optimized by using CODEV and ZEMAX software. Finally, a fish-eye lens has been designed successfully, whose FOV is 240 degrees, the F number is 2.2, and the total length is 23 mm. After that, this paper analyzes the quality of the image quality and the tolerance of the lens. The result shows that the aberration of the optical system has been corrected, and the transfer function of the optical system satisfies the design requirements. Finally, the stray light effectively has been eliminated through analyzing the stray light of the optical system.(4)This paper complementary illustrates the fish-eye lens methods of design and optimization by setting up specific parameters in CODEV software according to the research and design of a high resolution vehicle fish-eye lens. Finally, a high resolution vehicle fish-eye lens has been designed successfully, whose FOV is 197 degrees, the F number is 2.4, and the total length is 16.3 mm. Then, this paper analyzes the quality of the image quality and the tolerance of the lens. The results show that the panorama lens has a simple structure and good imaging quality compared to the ordinary VGA vehicle lens.(5)This paper emphasizes the study of manufacturing process of the 240 degrees panoramic fish-eye lens. Based on the basic theory of mold design, the whole structure of the 240 degrees panoramic fish-eye lens has been designed, which includes the structure of plastic lens and plastic barrel. This paper analyzes the key points of the mold designed and manufacture, and determines the plan of mold structure and the mold manufacture. Through the analysis of the characteristics of the common materials, the material with high capability has been selected. Through the understanding of the injection molding machine used in the experiment and the analysis and verification of injection molding theory, the common problems during the injection molding process has been solved. The problem of the internal stress of the plastic products has been creatively solved, so that production of plastic lens can go on well.(6)This paper provides the example of a lens with the transmittance in visible light band reaches 98% after coating. Furthermore, this paper assembles all the elements of the 240 degrees panoramic fish-eye lens. Finally, the performance of the lens has been proved to satisfy the requirements of design by evaluating the resolution of the lens through the method of projection.