Patent ID: 11572502

Abstract:
A wavelength conversion element includes a phosphor layer having phosphor particles and a binder, and a holding member including alumina, configured to hold the layer. The binder includes glass and is configured to bind a part the adjacent particles. The holding member has a pore, defining an apparent porosity thereof as X, bending strength A of the holding member fulfills A=−7.11X+316.52, an elastic modulus B of the holding member fulfills B=−6.26X+288.43, and defining an elastic modulus of the glass as C, 1/B+1/C=D, and a product of a difference between a linear expansion coefficient of the holding member and a linear expansion coefficient of the glass and a transition point of the glass as Y, Y<(A)(D)(0.001) when the linear expansion coefficient of the glass is smaller than the linear expansion coefficient of the holding member in a temperature range from the transition point of the glass to a room temperature.