WAVELENGTH CONVERSION MEMBER AND LIGHT-EMITTING DEVICE

摘要

Provided is a wavelength conversion member which exhibits reduced stress-strain generated at an interface between a fluorescent material layer and a substrate and which is unlikely to break during use. A wavelength conversion member 1 is obtained by joining a substrate 10 to a fluorescent material layer 20 in which an inorganic fluorescent material powder 22 is dispersed in a glass matrix 21. The wavelength conversion member is characterized by satisfying the relationship -10 × 10-7 ≤ α1-α2 ≤ 10 × 10-7 (/ºC) within a temperature range between 30ºC and the sticking point of the fluorescent material layer, wherein the coefficient of thermal expansion of the substrate 10 is denoted by α1 and the coefficient of thermal expansion of the fluorescent material layer 20 is denoted by α2. Here, the sticking point = Tf-(Tf-Tg)/3 (Tg: glass transition temperature, Tf: yield point).