Development of a computational modeling and experimental validation approach for KSF LED packages in a 65” ultra thin LED TV system

Abstract

The customer expectations in global TV market have changed over the last decade significantly towards a thinner with a higher brightness and a wider color gamut (WCG) TV products. These requirements led to a drastic increase in the power consumption and constrained mechanical design affecting the optical components and reducing the volume for thermal management. The KSF (K2SiF6:Mn 4+ ) LED is one of the best solutions to reach a higher color gamut (gamut > 90% in CIE 1976). However, the brightness of a typical KSF LEDs is about 15% lower than the conventional LEDs. KSF LED is also a thermally sensitive chemical compound but it enhances the color gamut of a TV system. Therefore, the determination of the best suitable LEDs for ultra thin TVs (thickness <; 7.9 mm) is critical since they are the main heat source consuming over 70% of total TV power consumption. Identifying thermally sensitive optical and mechanical components is one of the most essential steps of combined thermal and optical designs in an LED TV. At the same time, it offers significant advantages in terms of cost and time. Design and implementation of LED light engines (i.e. LED bars) is critical to reach performance goals of a high-end TV system. In this study, various LED bars consisting of KSF LED arrays and KSF chip scale packages (CSP) LED arrays have been studied both theoretically and experimentally. Modeling is started with analytical models (1D resistance network) and expanded to CFD analysis providing more accurate results capturing 3D heat transfer behavior. CFD simulations have been performed with a commercial CFD package (ICEPAK), and an experimental validation study has been performed to understand the thermal and the optical performance comparing different type of KSF LEDs in a TV system.