Patent ID: 9708533
Date: 2017-07-18
CPC Classifications: C04B,C09K,F21K,F21V,H01L

Claim:
1. A method of producing a wavelength conversion member composed of polycrystalline ceramics, comprising: i) mixing a substance serving as a silicon source, a substance serving as an aluminum source, a substance serving as a calcium source, and a substance serving as a europium source, ii) firing the obtained mixture to obtain an (oxy)nitride phosphor powder, iii) oxidizing the (oxy)nitride phosphor powder obtained in firing step ii), by a heat treatment at 800 to 1,200° C. in an oxygen-containing atmosphere, to obtain an oxynitride phosphor powder, and iv) sintering the oxynitride phosphor powder obtained in the firing step iii) to obtain polycrystalline ceramics, said polycrystalline ceramics comprising an α-sialon crystal phase and an aluminum nitride crystal phase, wherein the oxynitride phosphor powder sintered in the step iv) comprises Ca, Eu, Si, Al, N and O with a ratio of said Ca, Eu, Si, Al and N being a ratio of Ca, Eu, Si, Al and N in an (oxy)nitride phosphor represented by composition Formula (1): wherein x1, x2, y and z are 0<x1≦3.40, 0.05≦x2≦0.20, 3.5<y≦7.0, and 0≦z≦1, the oxygen content of the oxynitride phosphor powder being in excess of the theoretical oxygen content of the (oxy)nitride phosphor represented by composition Formula (1), the excess oxygen amount being from 1.1 to 11.5 mass % with respect to 100 mass % of the theoretical mass of the (oxy)nitride phosphor represented by composition Formula (1).