Research On Molding Technology Of Diffractive Optical Element

Diffractive Optical Element (DOE) is a kind of element which is structured on the surface and made by micromachining technology. It is based on the diffraction theory of light and computer design. The DOE not only have the advantages of small volume, light weight, but also have some special functions like eliminating the dispersion of light. With using the DOE, the number of lens in optical system is reduced, meanwhile the volume and weight of the system is decreased. So it has a very wide range of applications.The DOE is originally called binary optical elements (BOE). The development of its production methods has three stages:Binary optical elements fabrication, Multi-step binary optical elements fabrication and continuous molding fabrication of the DOE. The main manufacture methods of the DOE are:Photolithography, Direct Writing, Single Point Diamond Turning (SPDT), Embossing, etc. The embossing method is the key technology for mass production and has a high value of research. With this method, The DOE can be massive replicated. This thesis researched on embossing fabrication of the DOE, and the main contents are as follows:(1) The designing and manufacturing of the mold. The mold is made of copper with the method of single point diamond turning.(2) The selection and use of the mold material. This study selects polymethylmethacrylate (PMMA) as the mold material, analyzes its characteristics and compares with SU8.(3) The exploration and experiment of the embossing method. The study shows the reason of the defects and the key factors which affect the quality of the mold.(4) The transfer of the layer. After the structure is formed on PMMA, the transfer of the structure is studied. The structure is transferred with the help of ICP180etching system which is the produced by British Oxford. The etching rate of the substrate and PMMA is discussed. What’s more, the required parameters for transfer the structure are analyzed. In addition, the key factors which affect the etching results are analyzed. Finally the structure is transferred to the based material.