Patent ID: 11597879

Abstract:
The wavelength converter includes a support, and a wavelength conversion layer disposed on the support. The wavelength conversion layer contains a fluorescent layer containing a fluorescent material with a composition represented by formula (1) below, and having a thickness of from 5 μm to 155 μm. A ratio of a sum of cross-sectional areas of particles of the fluorescent material in a cross-section of the wavelength conversion layer orthogonal to a disposed surface of the wavelength conversion layer that is disposed on the support and including a full width of the wavelength conversion layer to a cross-sectional area of the cross-section of the wavelength conversion layer is from 5% to 40%. In the formula (1), M1 is at least one selected from the rare earth elements other than La and Ce; a total amount of yttrium (Y), gadolinium (Gd), and lutetium (Lu) by mole with respect to a total amount of M1 by mole is 90% or more; and p, q, r, and s satisfy 2.7≤p+q+r≤3.3, 0≤r≤1.2, 10≤s≤12, and 0<q≤1.2. LapCeqM1rSi6Ns  (1)