无热技术在光学系统中的应用

Application of athermalisation in optical systems

围绕环境温度对光学系统性能的影响及其解决方法,分析了温度效应的三个方面的因素:光学元件的折射率、曲率半径和中心厚度以及光学元件之间的空气间隔,并讨论了这三个因素与温度变化之间的关系。提出使用无热设计来消除温度效应对光学系统的影响,并且比较了当前三种无热技术之间的优缺点。最后给出了一个红外光学系统作为例子予以分析,在设计过程中使用了机械主动式无热技术,以补偿温度变化所产生的影响,通过比较使用无热设计前后系统的成像质量,说明了无热设计可以消除光学系统中温度效应的影响,使系统在较大的温度范围内保持较好的成像质量。

This paper focuses on the temperature effect and its solution. Analysis is made concerning temperature effect on three factors： refractive index of optical elements, curvature radius and center thickness of optical elements ,and the space distance between optical elements, and their relation to temperature variation are as well discussed. Athermalisation is introduced to eliminate the influence of temperature in optical systems, and the advantage and the disadvantage of the three athermalisations used currently are compared. An infrared optical system is taken for example. In the design process, the mechanical active athermalisation is used for eliminating the influence of the temperature change . And the image quality comparison with/without athermalisation is made. It is concluded that the influence of temperature effect could be eliminated so that the high image quality could be realized in a wide temperature range.