Optimization of InGaN-based LED Package Structure for Automotive Adaptive Driving Beam Headlamp

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.

A novel phosphor structure for improving the luminous flux of white LEDs

“…Scattered coefficient μsca is calculated using the Mie theory [20]- [23] to validate the optic characteristics of phosphor compounding. The equations below describe the relationship between the scattered coefficients (SC) and the wavelengths, and also the CaO:Sb 3+ phosphorus ions diameter:…”

Development of Radiator with Thermoplastic Polymer and Insert-Molded Aluminum Alloy Parts for Light-Emitting Diode Headlights

“…The life cycle impact of LED products is still not completely understood. As of 2022, phosphors, silicones, epoxies, and LEDs are still typically sent to landfills [9][10][11]. However, a major problem that reduces the lifetime of an LED system is the heating generated by the system itself [12][13][14].…”

Application of dual-layer phosphor geometries for enhancing the optical properties of white-light LEDs

“…Light emitting diodes (LEDs) were developed well and made available for commercial use not long ago, thanks to their exceptional performance, low power consumption, quick feedback, and significant endurance [2]. During the year 1994, Kim et al [3] created the earliest technique of annealing for mass-producing high-performance blue-light LEDs. Their work has contributed to the creation of the blue LED, which is based-GaN and covered with down-conversion substances (for example, aluminate phosphor [4] and quantum dot phosphor) [5], [6], and is amongst the most comm used techniques for producing white LEDs [2].…”