New coating strategy for hot embossing of glass

The hot embossing of glass received an enormous growth push through the mass production of aspheric lenses by precision glass moulding particularly in Asia in the last years. Deficits still exist regarding the accuracy and form filling, especially with double-sided embossed lenses or lens arrays, but also with non-optical applications as for instance micro fluidic systems. Particularly these structures with high aspect rations, sharp edges and steep walls in structure design cause substantial problems during the demoulding after embossing. Here, conventional tool coating delivers only small improvements, probably also because of moulds for fluid structures is very difficult and causes large problems. Against this background the research group at the Fraunhofer IWU is breaking new ground with its coating strategy. Not the forming tool, but the glass is provided with a coating, which prevents a sticking of the tool material to the glass.