Dispensed dome lens validation through optical simulations for high irradiance UV LED module

Abstract

Dome lens formation method through dispensing highly thixotropic encapsulant [1] has been introduced into LED industry for several years. It's cost-effective and concise in production flow, but not qualified yet when accurate optical properties are needed. Most of directional fixtures therefore require LED packages with precisely molded dome lenses, which need complex and expensive processes. In this paper, an optical model of LED package with dispensed dome lens is built for analysis. Variables including LED chip position, chip height and lens diameter are investigated through optical simulations. In order to validate the package with production deviations, ray files of the resulting packages are then applied to a linear collimator for high irradiance UV LED module as a test vehicle. The result shows that after intentionally designing for the process window in production, the package's light pattern is stable and its mean direction bias is below 2 degrees under deviations. Peak irradiance drops by 6.3% and total flux drops by 1% even in the corner case with surface mount technology (SMT) deviations in the linear collimator. It then leads to a conclusion that when dispensed dome lens has been well designed for process window, dispensed dome lens could be applied to lighting applications as well.