Omnidirectionally Encapsulated Phosphor‐in‐Glass Film Converter for Laser‐Driven Lighting Source

ABSTRACT A key obstacle in advancing high‐brightness lighting technology is the creation of laser‐driven color‐converting materials capable of integrated enhancement of optical and thermal performance. Herein, an omnidirectionally encapsulated color converter of phosphor‐in‐glass film (PiGF) was proposed, in which a hemispherical sapphire lens was integrated on the top surface of a BN‐in‐glass (BiG) layer‐surrounded PiGF coated on a sapphire substrate (L@PiGF@S). The L@PiGF@S converters with different YAG contents were prepared by thermocompression sintering, which display enhanced forward light extraction from lens integration and efficient heat dissipation from an omnidirectional heat conduction structure. This remarkable opto‐thermal cooperative effect enables an ultra‐high luminous efficacy (LE) of 268 lm/W and a maximum luminous flux (LF) of 6129 lm@36 W·mm −2 for the laser‐driven L@PiGF@S, which is 3 times of the common laser‐driven PiGF@S of 2022 lm@12 W·mm −2 . Importantly, the L@PiGF@S can produce a collimating and uniform white laser irradiation up to 1000 m, addressing the tough issues of large beam divergence and poor color distribution for the common PiGF@S. The developed L@PiGF@S converter demonstrates superior opto‐thermal performances, showing a great potential for a high‐brightness laser‐driven lighting source.