Color-Tunable White LEDs with Single Chip Realized through Phosphor Pattern and Thermal-Modulating Optical Film

Zhenpeng Su; Bo Zhao; Zheng Gong; Yang Peng; Fan Bai; Huai Zheng; Sang Woo Joo

doi:10.3390/mi12040421

Color-Tunable White LEDs with Single Chip Realized through Phosphor Pattern and Thermal-Modulating Optical Film

Micromachines (Basel). 2021 Apr 12;12(4):421. doi: 10.3390/mi12040421.

Authors

Zhenpeng Su¹, Bo Zhao², Zheng Gong², Yang Peng³, Fan Bai⁴, Huai Zheng^{1

2}, Sang Woo Joo⁴

Affiliations

¹ Institute of Technological Sciences, Wuhan University, Wuhan 430072, China.
² School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
³ School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
⁴ School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749, Korea.

Abstract

In this paper, a new method to regulate the correlated color temperature (CCT) of white light-emitting diodes (LEDs) is proposed for the single-chip packaging structure, in which the blue light distribution emitted from the chip in the red/yellow phosphor layer was modulated through changing the paraffin-polydimethylsiloxane (PDMS) film transparence and haze. The results show that the transmittance of the paraffin-PDMS film can be modulated from 49.76% to 97.64%, while the haze of that ranges from 88.19% to 63.10%. When the thickness of paraffin-PDMS film is 0.6 mm, and the paraffin-PDMS film concentration is 30 wt%, the CCT of white LED decreases from 15177 K to 3615 K with the increase of thermal load in the paraffin-PDMS film. The modulating range of its CCT reaches 11562 K. The maximum CCT variation at the same test condition is only 536 K in the repeated experiments within one week.

Keywords: LED packaging; correlated color temperature (CCT); light-emitting diodes (LEDs); paraffin-PDMS film.

Abstract

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