Replicative manufacturing of glass optics with functional microstructures
Microstructuring of glass optics enables a large variety of benefits for miscellaneous fields of application. From an enhancement of the performance of optical systems to the haptic improvement of coverglasses the advantages of structured glass are obvious. Especially in the field of high-precision optics, microstructured optical surfaces can carry out important functions, such as beam shaping in laser systems or the correction of dispersive color alterations. Besides enhancements regarding optics of the visible light spectrum, microstructures can compensate disadvantages of infrared(IR)-transmissive lenses such as chalcogenide glasses. As these optics suffer high transmission losses due to their high refractive index the integration of an anti-reflective (AR) function is necessary. Moth-eye-structures are a promising way to avoid the currently used AR-coatings. So far, microstructures are brought into the lens surface by lithography mainly. The therefore additional processing step follows the previous shaping. An efficient production of the structured components is the key to success for applications aside science and research. The technology precision glass molding (PGM) is able to combine the contradicting aspects of high precision and high volume production. PGM is a replicative manufacturing method that allows the macroscopic molding and the manufacturing of microscopic structures to be carried out simultaneously. Based on a representative PGM process chain, the paper at hand describes differences, challenges and current research results regarding molding microstructures.