Le Wang,Ran Wei,Peng Zheng,Shihai You,Tian-Liang Zhou,Wei Yi,Takashi Takeda,Naoto Hirosaki,Rong-Jun Xie
As a new generation advanced display or projection technology, laser displays or projectors have attracted great attention owing to their ultra-high brightness, energy saving nature, brilliant image quality and/or large sizes. However, for laser displays or projectors without using three primary laser diodes, the lack of appropriate blue-laser-driven color converters is a big limitation and challenge. In this work, we propose to develop laminated phosphor-in-glass (PiG) films as laser-driven color converters for wide-color-gamut and high-brightness laser displays. The β-Sialon:Eu and CaAlSiN3-LiSi2N2-Si2N2O, Calson:Ce phosphors were chosen as the green and orange emitters, respectively, and were co-fired with glass frits on a sapphire substrate to form PiG films. No interfacial reactions between phosphors and glass were identified, and phosphor powders were uniformly distributed in the glass matrix. The phosphor content and the film thickness had an influence on the microstructure, luminance saturation and optical properties of the PiG films under laser light irradiation; both PiG films reached a maximum luminance saturation of 6.09 W mm−2 when their microstructures were optimized. The lamination architecture of the PiG films had a great impact on the optical properties of the laser-driven white light, and the maximum ones were achieved as the green-emitting PiG film was positioned on the orange-emitting film adhered to the sapphire substrate. Under 4.82 W mm−2 blue laser excitation, the laminated double-layer PiG films enabled the creation of white light with a wide color gamut of 107% NTSC, luminous efficacy of 74.44 lm W−1, luminous flux of 282.13 lm and color temperature of 7902 K. These results indicate that the laminated PiG films are promising color converters for use in high-power and wide-color-gamut laser displays or projectors.
Jian Xu,Xin Liu,Zikang Yu,Hongjin Zhang,Zixiang Zhang,Yun Mou,Mingxiang Chen,Yang Peng,Qing Wang
Laser-driven white lighting is believed to be a future-oriented high-brightness solid-state light (SSL) source, which is confronted with a severe challenge in developing a laser-driven color converter with efficient thermal management. Herein, a unique architecture of phosphor-in-glass film bonded with a microchannel cooling (PiGF-MC) converter was proposed to enable high luminescence saturation for high-brightness laser-driven white lighting. The PiGF consisted of yellow-emitting Y 3 Al 5 O 12 :Ce 3+ (YAG) was sintered on an alumina substrate and then soldered on a liquid-cooled microchannel radiator, which realizes outstanding heat dissipation performance of laser-driven PiGF. The PiGF-MC converter possesses luminance saturation threshold under a high laser power density of 21 W mm −2 , 2.3 times that of the traditional PiGF-alumina converter (∼9 W mm −2 ). High-brightness laser-driven white light is achieved by the PiGF-MC with a high luminous flux of 2953 lm@21 W mm −2 , and long-term stable optical performance is simultaneously realized. The working temperatures of laser-driven PiGF-MC are all lower than 200 °C under various laser powers. This finding demonstrates the broad prospect of the proposed PiGF-MC converter architecture for next-generation high-brightness laser-driven white lighting.
Using blue lasers to excite green-emitting phosphors offers a compelling solution to address the “green gap” issue, providing a high-brightness green light source for underwater wireless optical communication (UWOC). However, current green-emitting phosphors show poor light conversion efficiencies or inadequate luminance saturation thresholds, impeding the development of brighter green light sources. Herein, the porous Lu 3 Al 5 O 12 :Ce phosphor ceramics are designed, which shows no change in quantum efficiency (82%) even after 6000 h of extended aging. This design results in a substantial improvement in light conversion efficiency (61.6%), luminous efficacy (286 lm·W⁻¹), and an exceptional luminance saturation threshold of 33 W·mm⁻ 2 , culminating in a maximum green light flux of 4720 lm. Moreover, the high-directionality green light source device has been fabricated that achieves an illuminance of 6081 lx at a distance of 10 meters (15.0 W blue laser irradiation) with the electro-optical conversion efficiency up to 26.3%, much higher than that using green laser directly (usually <20%). This setup enables long-range underwater transmission of 65.3 meters with a peak data rate of 3.45 MHz, opening up new avenues for innovative advancements in UWOC technology.