Unique Design Strategy for Laser‐Driven Color Converters Enabling Superhigh‐Luminance and High‐Directionality White Light. Issue 10 (10th September 2019)

• Record Type: Journal Article
• Authors: Zheng, Peng; Li, Shuxing; Wei, Ran; Wang, Le; Zhou, Tian‐Liang; Xu, Yi‐Rong; Takeda, Takashi; Hirosaki, Naoto; Xie, Rong‐Jun
• Is Part Of: Laser & photonics reviews. Volume 13:Issue 10(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-09-10
• Subjects: color converters -- laser‐driven lighting -- light confinement -- phosphor ceramics -- phosphor wheel -- scattering; Lasers -- Periodicals; Photonics -- Periodicals; Lasers -- Périodiques; Photonique -- Périodiques; 621.36
• DOI: 10.1002/lpor.201900147
• Languages: English
• ISSNs: 1863-8880

Abstract

Abstract: Robust ceramic color converters withstanding strong laser irradiations have recently drawn great attention for laser‐driven white lighting. However, the local emission within the incident laser spot usually expands to the whole surface area of the ceramics, which definitely makes it hard to achieve white light with high luminance and high directionality. Herein, a new strategy is proposed to solve the problem by elaborately introducing uniform spherical pores (diameter of ≈2 µm) into the phosphor ceramics with controlled contents from 8 to 24.6 vol%. The well‐distributed pores, acting as light scattering centers, enable reduction of the luminescent spot size greatly but without any losses in conversion efficiency. By using the high‐scattering ceramic color converters with 15% porosity, the light spot diameter is decreased by 46% and the central illuminance is increased by 156%. Moreover, laser‐driven white light with an enhanced beam directionality and uniformity is also achieved. A superhigh luminous flux of 7199 lm is realized by using this promising color converter in a rotary mode. The designed high‐scattering ceramics with controllable microstructures show great potential for use in extra‐high luminance laser‐driven lighting and projection. Abstract : Phosphor ceramics stand out in laser‐driven white lighting . A quite different design strategy is proposed to construct high‐light‐scattering ceramics. The beam expansion ratio is decreased from 3.14 to 1.68 and the center beam illuminance is increased by 156% in the highly scattering sample. Eventually, truly quasi‐point laser‐driven white light with high luminance and high directionality is achieved.