Abstract
The luminous properties of sphere-like remote phosphor white LEDs with high Correlated Color Temperature(CCT)and low CCT were studied under different drive currents and heat sink temperatures. The result shown that the quantum efficiency and luminous efficacy of both LEDs raise with the increase of heat sink temperatures;the high-CCT LED's quantum efficiency and luminous efficacy decrease with rising currents.However,the low-CCT LED shows a reverse trend.The reason is attributed to the quantum confinement stark effect in the active region,which makes the wavelength move towards shortwavelength so as to deviate from the optimum stimulation wavelength of the high-CCT phosphor,but close to the optimum stimulation wavelength of the low-CCT phosphor.The CCT of the high-CCT LED increase with rising currents,again,the low-CCT LED shows a reverse trend with rising currents.This trend is mainly related to the drifting of color coordinates caused by quantum efficiency changing.To sum up,the high-CCT LED possesses better optical properties but inferior color properties than the low-CCT LED.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
