Abstract
In the application of projection display, the effective
flux utilization is an important factor to the optical system
with more optical efficiency of the system with utilization of
the light source such as LEDs. In this paper, based on Monte
Carlo ray tracing we simulate light extraction efficiency as
well as directionality of the light pattern of sapphire-based
and Thin-GaN LEDs implanted with micro-pyramid structure with or
without lens encapsulation. We have shown that micro-pyramid
structures at some specific slanted angles in the LEDs are
useful to increase effective flux utilization through
enhancement of light extraction efficiency. In the case of the
sapphire-based GaN LEDs, the slanted angle in a range of
45° to 55°, with lens encapsulation, the
enhancement ratio of angular flux utilization is as high as
390%. In the case of Thin-GaN LEDs, both the slanted angle of
25° without lens encapsulation and 45° with
lens encapsulation (LEC) are effective ways to obtain high
angular flux utilization. The enhancement ratio of angular flux
utilization is as high as 500% or more and the light extraction
efficiency in 30° light cone reaches more than 18%.
© 2011 IEEE
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