The Preparation and Properties Study of High CRI White LED Based on Remote Phosphor Technology

Focusing on the defects in the lighting color of LED lamps and the chip heat exists in the traditional LED package which caused phosphor performance degradation, color temperature drift and the uneven light, the remote phosphor package which is emerging in recent years is used in this paper. With yellow-green YGG phosphor and nitrogen red phosphors mixing with silica gel, the remote phosphor is made and then encapsulated as the LED lamps. A lot of experiments were made to determine the best ratio of yellow green phosphor, red phosphor and silica gel, LED lamps with different color temperature was prepared. The lamps were also tested and analyzed with some parameters such as e color coordinates, luminous efficiency, color rendering index (CRI), R9, color quality scale (CQS), color temperature, and the gamut area index (GAI), which provide a more objective and comprehensive evaluation to the high quality LED lighting. Experimental results show that the optimum ratio of red and yellow-green phosphor is 1∶7.6, and total phosphor with silica gel is 1∶5，at this time the white LED lighting color temperature is 4 113 K, the color coordinate (x, y) is (0.375 4, 0.373 1), luminous efficiency is 52.33 lm·w-1, color gamut is 0.981, color rendering index is up to 96, R9 is 97, color quality scale Qa is up to 93, and the gamut area index is 79. Compared with the traditional packaging，the surface temperature ofthe remote phosphor encapsulated fluorescent plate is much lower than that of adhesive dispensing encapsulation, which can effectively avoid the harmful effect caused by high temperature on the LED.