High Performance and Reliability of Two-Inch Phosphor-in-Glass for White Light-Emitting Diodes Employing Novel Wet-Type Cold Isostatic Pressing

Abstract

High color rendering index (CRI) of 97 and wide correlated-color temperatures (CCTs) range of 2100–7600 K in white light-emitting diodes (WLEDs) employing the two-inch diameter of CaAlSiN3: Eu2+ (red phosphor) and Lu3Al5O12: Ce3+ (green phosphor) co-doped phosphor-in-glass (PiG) are demonstrated by a novel wet-type cold isostatic pressing (CIP) technique. The wet-type CIP enable to apply isostatic pressure to a powder sample in all directions to obtain the PiG with excellent optical properties, high reliability, and thermal stability. The high CRI of 97 and the wide CCTs range of 2100–7600 K achieved are mainly due to the optimized phosphor materials and the precise adjustment thickness of the PiG. Based on the best formula of two-inch diameter PiG and a unique process of wet-type CIP, we have successfully fabricated and demonstrated the good uniformity and excellent performances of a large diameter of two-inch PiG. The proposed of a large diameter of two-inch PiG with excellent performance, high reliability, and thermal stability is essential to meet the economic dimension requirement for commercial usages in high-quality WLEDs indoor lighting applications.

Keywords

• White light-emitting diodes (WLEDs)
• phosphor-in-glass (PiG)
• color rendering index (CRI)
• correlated-color temperature (CCT)
• wet-type cold isostatic pressing (CIP)