Chen Z.-P.,Wenzhou University |
Xiang W.-D.,Wenzhou University |
Liu H.-T.,Wenzhou University |
Liang X.-J.,Wenzhou University |
Zou J.,Zhejiang Emitting Optoelectronic Technology Co.
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2014
Ce, Sm:YAG single crystals doped with different concentrations of Sm3+ were grown by the Czochralski method. The crystal structure and optical properties were analyzed by the X-ray diffraction(XRD), absorption photoluminescence spectra. The color coordinates, luminous efficiency, color rendering index and other characteristics of the LED light source were analyzed by LED fast spectrometer. The results indicate that the main phase of Ce, Sm:YAG single crystals grown by Czochralski method was YAG crystal phase. As the Sm3+ concentration increasing, the YAG crystal structure unchanged, the red luminescence spectra intensity increased, and the CRI of white LED was also increased. When the actual concentration of Ce, Sm:YAG single crystal was 0.31wt% and the slice thickness was 0.2 mm, the light efficiency of the sample was 98.837 lm/W and the color rendering index was 71.1, which meet the requirement of commercial white LED.
Zou J.,Shanghai Institute of Technology |
Li Y.,Shanghai Institute of Technology |
Zhu W.,Zhejiang Emitting Optoelectronic Technology Co. |
Chen H.,Zhejiang Emitting Optoelectronic Technology Co. |
And 4 more authors.
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2015
The luminescence performance characterized by luminous flux, color temperature, chromaticity coordinate of three-dimensional light emitting diodes (LEDs) has been investigated by using different phosphor coating methods. The LED die was directly coating with mixed phosphors and silicone which have the maximum total luminous flux. However, this encapsulation incurs luminous uneven problem of front and back which limit three-dimensional luminescence application. Therefore, this work attempts to use the silicon and spreading powder to change the light path on the basis of less loss of luminous flux. Experimental results indicate that the brightness uniformity can be improved when increasing silicon layer between LED die and phosphor, while spreading powder layer would induce significant light attenuation. Moreover, the three packing have similar light angle. Therefore, silicon layer provides an alternative packing solution for three-dimensional LED light application. ©, 2015, Chines Academy of Sciences. All right reserved.