LED LIGHT-EMITTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a white LED composed of a combination of an LED excitation light source and a phosphor, which exhibits both high luminous efficiency and high color rendering properties.

SOLUTION: An LED light-emitting device comprises an LED chip and a yellow phosphor layer and a red phosphor layer which are disposed along a light path radiated from the LED chip toward the outside. In the LED light-emitting device, when a thickness t1 of the yellow phosphor layer along a light path radiated from the LED chip toward the outside is expressed in μm and a mass percent concentration wt% of the phosphor relative to the entire mass of the yellow phosphor layer is expressed by w1, it is assumed that t1×w1=A, and when a thickness t2 of the red phosphor layer along a light path radiated from the LED chip toward the outside is expressed in μm and the mass percent concentration wt% of the phosphor relative to the entire mass of the red phosphor layer is expressed by w2, it is assumed that t2×w2=B, and then values of A and B satisfy the relationships of 4000≥A≥10000 and 0COPYRIGHT: (C)2012,JPO&INPIT