Optimization of InGaN-based LED Package Structure for Automotive Adaptive Driving Beam Headlamp. (26th June 2020)

• Record Type: Journal Article
• Authors: Kim, Ho-Young; Kim, Min-Su; Lee, Kwang-Hee; Kang, Kyoung-Mo; Oh, Jeong-Tak; Jeong, Hwan-Hee; Seong, Tae-Yeon
• Is Part Of: ECS journal of solid state science and technology. Volume 9:Number 5(2020)
• Publication Date: 2020-06-26
• Subjects: Light-emitting diode -- Solid State Lighting - Packaging -- luminance -- Thermo-mechanical stress -- Thermal resistance; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2162-8777/ab9dc6
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : We investigated the luminance, thermal, and thermo-mechanical properties of vertical (V)-LED and flip-chip (FC)-LED packages with different white silicones for a vehicle head lamp application. The FC-LED package showed higher equivalent maximum stress than the V-LED package. For example, the equivalent maximum stresses for the FC-LED package with white silicone (WR-3020) were 6.05 and 2.45 MPa at −45 and 125 °C, respectively, whereas those for the V-LED one with WR-3001 were 1.09 and 1.56 MPa. Irrespective of currents, the V-LED packages exhibited lower thermal resistance (Rth ) than the FC-LED package. The V-LED package showed 25.3% lower Rth value (junction to PCB) at 1000 mA than the FC-LED package. The FC-LED packages illustrated higher luminous flux drop-rate at 85 °C than the V-LED package. The V-LED packages revealed lower surface temperature than the FC-LED package. The contrast ratio depended on the package structures and white silicone coating widths. The packages with the wider edge-coating width had higher luminance and the V-LED packages exhibited higher luminance. The luminous flux maintenance rate was degraded by 0.9%–2.9% after 1000 h. The V-LED package with WR-3001 showed the best performance, while the FC-LED package with WR-3020 displayed the lowest performance.