Non‐Isothermal Glass Moulding of Complex Led Optics

The advantages of LED lighting, especially its energy efficiency and the long service life have led to a wide distribution of LED technology in the world. However, in order to make fully use of the great potential that LED lighting offers, complex optics are required to distribute the emitted light from the LED efficiently. Nowadays, many applications use polymer optics which can be manufactured at low costs. However, due to ever increasing luminous power which goes along with increasing temperatures and UV radiation, polymer optics reach their technological limits. Due to its outstanding properties, especially its temperature resistance, resistance against UV radiation and its long term stability, glass is the alternative material of choice for the use in LED optics. However, growing demands for complex yet low-cost glass optics pose a major challenge for glass manufacturers. Companies are continuously being confronted with the challenge arising from the trend towards increasingly complex geometries, ever higher levels of precision combined with a fast changing market and immense pressure on market prices. This research is introducing a new replicative glass manufacturing approach, namely non-isothermal glass molding (NGM) in which glass preforms are reheated and molded into its final shape. New, flexible mold concepts are introduced to account for the optics’ ever increasing complexity. Besides, alternative mold materials in combination with ultra-precision mold manufacturing technologies, namely ultra-sonic assisted diamond turning are used to guarantee highest form accuracy of the used molding tools. The key to success for a fast time to market is the integration of FEM simulation at the early stage of the process development, which will also be presented in this research. This thermos-mechanical process modeling provides a systematic approach for glass preform design, mold compensation, and process optimization. Finally, a business case including machine concepts is presented for competitive serial production from 10.000 up to 30 Mio. optics per year. In conclusion, short process times in conjunction with the elimination of any requirement for finishing work to be conducted on parts, have made NGM the technology of choice for serial production of complex LED glass optics.