Diffractive optical elements are widely used in optical systems due to their excellent dispersion characteristics. Precision molding technology is an effective way to solve mass optical processing. Based on the precise molding of the chalcogenide glass diffractive optics, in this paper microstructure filling and process parameter sensitivity of diffractive optical elements are analyzed. The research results show that the use of appropriate process parameters can ensure the filling of diffractive microstructures. The cooling rate in the slow cooling stage is the most important factor affecting the surface shape.

衍射光学元件较球面、非球面光学元件在校正色差方面具备较大优势,尤其是在红外光学领域,应用衍射光学元件可进一步增加光学系统的设计自由度.随着红外光学市场的进一步增大,常规的衍射光学金刚石车削技术难以满足大规模需求,精密模压技术成为解决上述问题的关键技术.模具设计是实现精密模压的重点,为了缩减模具设计周期,该文采用有限元仿真方法对模具进行预先设计及补偿,并试加工.采用单站式精密模压机对设计的模具进行了精密模压试验.模压试验结果表明:采用合理的工艺参数,能够实现衍射光学元件面形精度PV达到0.56?μm,位置误差<0.011?mm,环带高度误差<0.12?μm,验证了仿真预先补偿在衍射光学模具设计中的有效性.

在光学加工领域,采用功率谱密度(power spectral density, PSD)对误差频谱方面信息进行表征,但是功率谱密度是表面误差统计信息,不如峰谷值 (peak-valley,PV)和均方根值(root mean square,RMS)直观。为了分析功率谱密度与工艺参数之间的关系,该文从PSD定义出发,分析了随机面形轮廓不同参数对光学PSD的影响规律,总结了PSD控制的要点,在平面玻璃上对数控抛光典型路径下加工的PSD曲线进行分析。分析结果表明:PSD与随机轮廓幅值、频率分布有关,相位对它几乎无影响;在RMS接近情况下,PSD线性拟合斜率和RMS Slope随随机轮廓的自相关长度增加而下降;短程加工路径相较于长程有序路径能够有效抑制PSD曲线峰值,使得光学元件符合频谱抑制要求。

According to the difficulty of cutting the ZTC4 material, slot cutting experiments were designed and three directional dynamic milling force were obtained. Instantaneous milling force model and multiple linear regression was used to analyze three directional milling force coefficients and edge milling force coefficients. To evaluate the performance of the dynamic milling force model, a new slot cutting experiment was designed. The comparison of simulations and experiments indicates the average milling force error are 5.74%, 3.93%, 7.98%, the dynamic milling force prediction model fits well in cycle, trend and amplitude. The feasibility and accuracy of the model for predicting the instantaneous milling force is verified.

The primary mirror component is an important part of the Cassegrain system. As the first-stage imaging component, the RMS surface error directly affects the image quality of the whole optical system. In this article, taking the primary mirror component of a certain type of Cassegrain aerial camera as the research object, the factors affecting the RMS precision of the primary mirror surface are analyzed in detail from aspects of back supporting structure design, platen elastic crimping design, simulation analysis, test verification and so on. Using the finite element method to simulate the primary mirror supporting structure, analyzes the influence on the primary surface error by the three-point supporting structure in different positions. Furthermore, analyzes the variations of the primary mirror surface error under the influence of three-point supporting structure and pressure plate. The last but not the least, analyzes the primary mirror surface error under the different pressure conditions, concludes the optimal supporting point position and the excellent elastic compression. After the primary mirror assembling, through test verification, the RMS is 0.0270λ, which is better than the original design requirement of λ/35(0.0286λ). And the RMS variation between before and after assembling is less than 0.005λ. Performing the high and low temperature test on the primary component, after test, the RMS values is 0.0269λ, it proves that the primary frame structure and its axial supporting structure have little effects on the RMS precision of the primary mirror. It can also meet the requirement of the large-aperture primary mirror surface in the co-optical system under complex conditions. The feasibility of the structure design has been verified.

Large angle wedge parts were widely used in the optical system that was used for achieving a wide range of scanning. Due to the parts having the characteristic of large difference in the thickness of both ends and high density, the accuracy of the wedge angle was hard to ensure to reach second level in optical processing. Generally, wedge mirror angle was measured by contact comparison method which was easy to damage the surface. In view of the existence of two practical problems, in this paper, based on theoretical analysis, by taking three key measures that were the accurate positioning for the central position of the large angle wedge part, the accuracy control of angle precision machined of wedge mirror and fast and non destructive laser assisted absolute measurement of large angle wedge, the qualified rate of parts were increased to 100%, a feasible, controllable and efficient process route for large angle infrared wedge parts was found out.