Effect of composition and package structure of bi-color flexible remote phosphor film on the properties of remote white LEDs

Abstract

A new bi-color flexible remote phosphor film was prepared to gain remote white LEDs with high luminous efficiency, low color temperature and high color rendering index. The research results indicate that the proposed bi-color phosphor film with yellow and red phosphors at mass ratio of 12:1 generates pure white light as simply encapsulated into 1Watt blue LED bead, which shows average luminous efficiency of 143.5 lm/W, average Tc of 5214 K and mean CRI of 76. Single layer packaging is a more suitable structure for proposed bi-color phosphor film used in general white lighting with chip-on-board LEDs, as compared with double layer package in this work. Furthermore, the remote phosphor distance of about 12 mm is appropriate for prepared 12:1 bi-color phosphor film to obtain high-power remote planar white LEDs with high brightness, low color temperature and even lighting output.