Research On Infrared Glass Optical Element Molding Technology

The mold pressing technology is a highly efficient method for fabricating the optical element with ultra sophisticated surface shape. Using this kind of technology, instead of the traditional method, to fabricate the aspheric lens or diffractive lens could not only reduce the waste of the optical element material during the removal process and the cost of the complex process, but also could achieve mass production. And so more and more attentions were paid on the infrared glass optical element mold pressing technology, because infrared glass is an amorphous material and very suitable to be molded.Firstly, the hybrid infrared optical system of refractive/diffractive is designed by ZEMAX, and the diffractive elements diffraction system surface was simulated and processed, and mold was fabricated.The results were shown as follows.1 The refractive/diffractive infrared optical system was designed, and the maximum rms reached to 15.159μm by analyzing spot diagram which is less than a pixel size of 26μm.In order to deeply analyze the optical resolution of the system, the optical transfer function is 0.13 at the 381p/mm, closing to the diffraction limit. The optical transfer function of the full field view are greater than 0.1.2 The changing rules of the corrosion rates in both the solutions with different temperatures and densities were studied. The results show that the surface roughness and corrosion depth of silicon dioxide relate to the corrosion rate which controlled by both temperature condition and composition concentration. We have conformed corrosion rate of silicon dioxide variation under different conditions. So the proper techniques of chemical corrosion can be chosen at different aims in the practical applications.3 The Silica mold was patterned by photolithography technique and lift-off process and wet etching process. The detection results showed that the average precision reaches to 74% in the range of 0.9 × 0.9mm.