Laser-excited single crystal phosphor in white LED for wide field of view and high enhanced central brightness for vehicle headlights

Hsing-Kun Shih,Kenneth Li,Chun-Nien Liu,Yung-Peng Chang,Wood-Hi Cheng

doi:10.1063/5.0069586

Abstract

We demonstrate the generation of a laser hotspot by a laser-excited single crystal phosphor (SCP) converter layer in a white LED for producing a wide field of view (FOV) and high enhanced central brightness (ECB) for an adaptive-driving-beam (ADB) headlight. The SCP layer shows better thermal quench behavior than other phosphor converter layers because of the higher melting temperature of 1940 °C and larger thermal conductivity of 11 W/m°C. The advantage of this study is an optical design of the ADB headlight, in which the generation, mechanism, and characterization of the laser hotspot are investigated in detail. The proposed scheme enables a wide FOV of ±16.8° and high ECB of the high beam, compliant with the Economic Commission for Europe regulation of vehicle headlights. The wide FOV provides better visibility, while the high ECB improves the long-distance illumination of the headlights. This proposed ADB headlight is a promising headlight candidate for use in the next-generation autonomous vehicle applications.

Highlights

Al orientation of the preform to be grown
The ADB headlight consists of a collimating lens pair, a digital mirror devices (DMDs), a total-internal-reflection prism, a wide field of view (FOV) projection optics system, and a laser-excited single crystal phosphor (SCP) in the white LED
The results showed that the ratio of Ce, Y, Al, and O ions in the SCP were estimated to be around 0.46 at%, 24.46 at%, 27.60 at%, and 47.48 at%, respectively

Summary

Introduction

Al orientation of the preform to be grown. When the descending seed crystal came in contact with the phosphor melt, the Czochralski growth process began. It is difficult to obtain both a wide FOV and high ECB of the ADB headlight at the same time by using only blue LED-excited phosphor as the white light source. The ADB headlight consists of a collimating lens pair, a DMD, a total-internal-reflection prism, a wide FOV projection optics system, and a laser-excited SCP in the white LED.

Results

Conclusion