Wide-Angle Mini-Light-Emitting Diodes without Optical Lens for an Ultrathin Flexible Light Source

Yen-Lung Chen; Wen-Chung Chin; Chun-Wei Tsai; Chang-Che Chiu; Ching-Ho Tien; Zhi-Ting Ye; Pin Han

doi:10.3390/mi13081326

Wide-Angle Mini-Light-Emitting Diodes without Optical Lens for an Ultrathin Flexible Light Source

Micromachines (Basel). 2022 Aug 16;13(8):1326. doi: 10.3390/mi13081326.

Authors

Yen-Lung Chen¹, Wen-Chung Chin², Chun-Wei Tsai³, Chang-Che Chiu⁴, Ching-Ho Tien⁵, Zhi-Ting Ye⁴, Pin Han¹

Affiliations

¹ Graduate Institute of Precision Engineering, National Chung Hsing University, Taichung 402, Taiwan.
² Department of R&D Center, TOP RAYS Co., Ltd., Taichung 402, Taiwan.
³ Department of R&D Center, i-Wavefront Technology Ltd., New Taipei City 231625, Taiwan.
⁴ Department of Mechanical Engineering, Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, Taichung 402, Taiwan.
⁵ Department of Electronic Engineering, Lunghwa University of Science and Technology, Taoyuan 333326, Taiwan.

Abstract

This report outlines a proposed method of packaging wide-angle (WA) mini-light-emitting diode (mini-LED) devices without optical lenses to create a highly efficient, ultrathin, flexible planar backlight for portable quantum dot light-emitting diode (QLED) displays. Since the luminous intensity curve for mini-LEDs generally recommends a beam angle of 120°, numerous LEDs are necessary to achieve a uniform surface light source for a QLED backlight. The light-guide layer and diffusion layer were packaged together on a chip surface to create WA mini-LEDs with a viewing angle of 180°. These chips were then combined with a quantum dot (QD) film and an optical film to create a high-efficiency, ultrathin, flexible planar light source with excellent color purity that can be used as a QLED display backlight. A 6 in (14.4 cm) light source was used as an experimental sample. When 1.44 W was supplied to the sample, the 3200-piece WA mini-LED with a flexible planar QLED display had a beam angle of 180° on the luminous intensity curve, a planar backlight thickness of 0.98 mm, a luminance of 10,322 nits, and a luminance uniformity of 92%.

Keywords: QLED display; flexible; luminous intensity curve; mini-light-emitting diodes; wide angle.

Grants and funding

This work was supported by the Ministry of Science and Technology (MOST) of Taiwan, under contract numbers MOST 110-2221-E-194-036, 111-2221-E-005-033, MY2, and 110RB02.