Preparation Of Multi-Color Phosphor-in-glass And Its Application For LED Packaging

Light-emitting diode(LED)has been widely applied into various illumination applications owing to its outstanding performance and characteristics of environmental protection.Most white LED uses blue LED chips to excite yellow phosphors.Due to the poor thermal stability of silicone and epoxy resin,it is easy to appear yellowing when working in high temperature for a long time,which will affects the luminescent properties of LED.The CRI of the white light LED is generally low,usually less than 70.To solve these problems,a feasible scheme was proposed to produce multi-color phosphor-in-glass(PiG)by screen-printing and low-temperature sintering methods.The UV chip was used to excite multi-color PiG to get better optical performance.The properties of multi-color PiG was analyzed,including microstructure and constituent analysis,emission spectra,excitation spectra and transmittance.It is concluded that the optimized sintering temperature is from 600 to 630 C.Optical performance of white light LED packaged by multi-color PiG were studied.There are three parameters: proportion of three kinds of phosphor,the thickness of multi-color PiG and the weight ratio of the phosphor to the glass powder.The research showed when the ratio of R:G:B is 2:3:2,the thickness of the multi-color PiG is 75 u m and the ratio of phosphor powder to glass powder is 2:1,the optical performance of the white light are the best,the CRI is 92.6,the luminous efficacy is 27.8 lm/W,and the CCT is 4245 K.The structure of multi-color PiG was optimized,R-G-B and G-R-B multilayered PiGs were proposed to improve the luminous efficiency of white LED.The luminous efficiency of R-G-B and G-R-B PIG increased from 23.12lm/W to 25.02 lm/W and 27.19lm/W by 8.2% and 17.6% respectively.Finally,the thermal reliability test of multi-color PiG was carried out.The results showed that the multi-color PiG has good thermal reliability.