Thermal Effects For Optical System And Athermal Design Of Lenses

When the optical system works over a wide range of temperature,the increase of decrease of the ambient temperature will cause the change of the optical and structural parameters of the optical elements,which will cause the degradation of the image quality.Therefore,for the optical system working in the above type of environment,it is necessary to consider the influence of temperature in the design,that is,to take certain measures to enable the optical system to maintain good optical performance over a wide range of temperature.In the past,most of the optical systems for thermal analysis were infrared lenses,aerospace lenses and so on.At present,with the widespread use of plastic lenses and the diversification of the environment of optical systems,more types of lenses need to maintain good optical performance over a wide range of temperature,that is,it is necessary to study the athermal design methods and characteristics of other types of lenses.First of all,this paper studies the basic theory of thermal analysis of optical system,analyzes the relationship between the optical and structural parameters of the optical system and the temperature,and analyzes and compares three athermal techniques of optical systems.Secondly,this article analyzes the existing thermal analysis function of CODE V optical design software and points out its deficiencies.Based on the research and deriving of thermal model of the optical system and calculation formulas,the CODE V macro files have been written to realize the new thermal analysis function which is more in line with the actual situation.This new thermal analysis function can be used to design the athermal system during the optimization of the optical system.Thirdly,this article uses the new thermal analysis function written in this article to complete the athermal design of a day and night confocal vehicle lens with large field of view and a glass-plastic hybrid day and night monitor lens,and analyzes the optimization design process of the vehicle lens and monitor lens in detail according to the design steps.The design results have been analyzed for image quality and tolerance,and the monitor lens’s flare has also been analyzed.The two lenses maintained good image quality over a wide range of working temperature,meeting the design index requirements and realizing the athermal design of the vehicle lens and monitor lens.Finally,using the special image testing software Imatest to test and analyze the image quality of the actual images of the monitor lens.The analysis results show that the image quality of the monitor lens designed in this paper is good,verifying the accuracy and reliability of the optimization by using the CODE V macro files written in this paper.