Development of passive and active microprism arrays to change the radiation pattern of solid-state lighting

Abstract

This study implements a compact solid-state lighting chip with changeable illumination map as well as radiation pattern. The lighting chip consists of a microprism array, light-emitting diode (LED) chip and Si carrier. The polydimethylsiloxane (PDMS) and polymer-dispersed liquid crystal (PDLC) layers are respectively employed to implement the passive and active microprism arrays. The specific radiation pattern can be defined by the shape of the passive PDMS-microprism. Moreover, by using the scattering and transmitting modes of the PDLC layer, the PDLC-microprism enables the changing of light shaping by applying voltage. Thus, the radiation pattern can be changed by the driving voltage on the PDLC layer, and the deformable and movable micro optical components are not required. This study has established the low-temperature fabrication and packaging processes to realize the lighting chip, and the damage of the PDMS and PDLC material is prevented. Typical dimensions of the PDMS lighting chip are 5 mm wide, 6 mm long and 1 mm thick, and The PDLC lighting chip is 550 μm thick. The measurement results show that the PDMS-microprism array can change the radiation pattern from a 70 • half-maximum viewing angle to 52 • and 40 • half-maximum viewing angles on two orthogonal axes. In addition, the PDLC-microprism array can change the radiation pattern from 51 • and 43 • half-maximum viewing angles at 0 V (i.e. scattering mode) to 48 • and 33 • half-maximum viewing angles at 100 V (i.e. transmitting mode).

Active Optical Beam Shaping Based on Liquid Crystals and Polymer Micro-Structures

“…Crystals 2020, 10, x FOR PEER REVIEW 2 of 25 micrometer scale [4][5][6][7][8][9][10]. However, sophisticated device structures and small device dimensions inhibit their applications in large-area light beam shaping.…”

“…Micro-electro-mechanical systems (MEMS) based beam manipulation is among the most promising technologies. One can manipulate a light beam propagation through MEMS controlled micro lenses, micro mirrors, or micro prisms at the micrometer scale [4][5][6][7][8][9][10]. However, sophisticated device structures and small device dimensions inhibit their applications in large-area light beam shaping.…”