Laser-driven phosphor-converted white light source for solid-state illumination

Abstract

Energy efficiency and lighting quality considerations are driving research into laser-pumped white light sources. Laser diodes as pump sources for downconversion phosphors promise freedom from "droop" that adversely affects the efficiency of light-emitting diodes (LEDs). High-intensity laser diode-pumped light sources for applications such as search lights and automobile headlights have been demonstrated recently. Our paper describes the design and construction of a domestic/office-type solid-state luminaire driven by light from an integrated violet laser-diode module. A trichromatic phosphor made from a blend of separate europium-containing rare-earth phosphors was used as the downconversion medium. Mechanical and optical design of the reflector and the phosphor plate are described. Characteristics of both the pump light and the downconverted light are also described. Our studies also looked at the variation of chromaticity coordinates with variation in pump power and the effect of laser speckle on the lamp's light output. Finally, there is a brief discussion of energy conversion efficiency and longevity considerations, comparing pumping with LEDs versus pumping with laser diodes.

Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

“…George et al. carried out a geometric ray‐tracing simulation to investigate the light uniformity of this luminaire assembly . A geometric model was set up, which consists of a parabolic‐figured reflector with an aluminized inner surface (95% reflectance), a phosphor plate, a double concave glass lens, and a cylindrical adapter.…”

“…c) Laser speckle pattern on the phosphor plate, and the intensity color code scale is on the right (minimum 0 to maximum 1). Reproduced with permission . Copyright 2016, Optical Society of America Publishing.…”

Investigation of Saturation Effects in Ceramic Phosphors for Laser Lighting

“…Consequently, to ensure a high efficiency together with high flux, an increase in the number of LED chips operated at low current densities is needed. A good alternative for achieving high-luminance white light sources is using phosphor converted blue laser diodes (PC-LD) [ 7 , 8 , 9 , 10 , 11 , 12 ]. Replacing LEDs with laser diodes (LD) as a solid-state lighting source could be a solution for the “efficiency droop” at high input power densities.…”

Investigation into the Anomalous Temperature Characteristics of InGaN Double Quantum Well Blue Laser Diodes Using Numerical Simulation

“…Recently, GaN-based blue laser diodes (LDs) have attracted great attention for use in laser-based white lighting [ 1 – 3 ] and visible light communication applications [ 4 – 7 ]. The blue LD-based white light source can eliminate the “efficiency droop” problem, which has been commonly observed in GaN-based light-emitting diodes (LEDs) at high injection currents [ 1 , 8 – 10 ].…”