Analysis and research on color parameter drift and thermal properties of packaged light source applied in education

With the development of chip scale package (CSP) light-emitting diode (LED) technology, this technology is more and more widely concerned and applied in semiconductor lighting industry. When LED is used in the lighting on education, its characteristics such as color rendering index (CRI) and color temperature are particularly important. This paper introduces one design of CSP LED with 630 nm K
2
SiF
6
(KSF) fluoride phosphors in the mixed phosphors layer. The spectral characteristics, color parameter drift and thermal characteristics of the CSP LED are studied. The CSP technology achieve high CRI (>95) along with high luminous efficacy (158.81 lm/W). The results show that: 1) The driving current and temperature have different effects on the optical, color parameter drift and thermal properties of the device; 2) The added KSF fluoride phosphors expand the luminescence spectrum distribution and improves the luminescence intensity, especially in the red band (600 nm~650 nm); 3) The CRI is improved without significant reduction in luminous efficiency, and it achieved the trade-off between CRI and luminous efficiency.