ALUMINA MATERIAL, TRANSLUCENT ALUMINA PORCELAIN, AND LED ILLUMINATION

摘要

PROBLEM TO BE SOLVED: To provide an alumina material for restraining transmission of blue light, translucent alumina porcelain, and an LED illumination.SOLUTION: The alumina material contains 99.7 mass% or more of AlO, 0.1-10 ppm of Cr in terms of the oxide thereof (CrO), and 0.1-10 ppm of Ni in terms of the oxide thereof (NiO) and has 25% or higher of an average value A1 of spectral absorptivities at 380-500 nm wavelength. The translucent alumina porcelain has the same composition as that of the alumina material and alumina crystal grains and grain boundaries and 0.5% or smaller porosity. When the average value of the spectral transmissivities at 380-500 nm wavelength is defined as T1 and that of the spectral transmissivities at 500-780 nm wavelength is defined as T2, T2 is 25% or higher and T1 is 65% or lower of T2.SELECTED DRAWING: Figure 1