Manufacturing of glass diffractive optics by use of molding process

Through design, fabrication and measurement of compression molded low T(ind g) glass DOE (diffractive optical elements) as well as measuring the optical performances of the molded glass DOEs, we have demonstrated that compression molding can be a promising process for high volume production of precision DOEs with micro and nano scale features. Geometrical characterizations of the molded DOEs were demonstrated using different optical metrology techniques. The DOE molding experiments discussed in this paper were performed on a Toshiba GMP 211V machine at the Fraunhofer Institute for Production Technology (IPT). The glassy carbon wafers used in this research were manufactured by Tokai Carbon Co. Ltd., Tokyo, Japan). The glassy carbon wafers were optically polished before the diffractive pattern was fabricated in the cleanroom. The proposed strategy for DOE fabrication has several inherited advantages over existing technologies. First, it is flexible in that there are several hundred optical glasses available versus only a few optical plastics. Second the molded DOEs can preserve the optical quality of the mold surfaces, therefore, no post molding processes are needed, i.e., it is a net shape manufacturing process. Third, this method can be applied to fabricating many different optical components thus making it a very powerful tool to mass produce various optical elements at low cost which opens the door for enhanced and more affordable optical systems. Finally, the compression molding process can be used to fabricate other components with micro and nanoscale features at an affordable cost, for example, microfluidic devices for biomedical applications.