CPC C04B 35/10 (2013.01) [G02B 5/003 (2013.01); C04B 2235/3217 (2013.01); C04B 2235/3237 (2013.01); C04B 2235/3241 (2013.01); C04B 2235/3262 (2013.01); C04B 2235/3272 (2013.01); C04B 2235/3275 (2013.01); C04B 2235/3279 (2013.01); C04B 2235/9661 (2013.01); F21S 41/40 (2018.01); G01J 5/06 (2013.01); G01J 2005/065 (2013.01)] | 3 Claims |
1. A light shielding member, disposed around an optical element to block unnecessary light and comprising an aluminum oxide ceramics comprising an oxide of titanium whose composition formula is shown as TiO2-x (1≤x<2),
wherein
a total content of Fe, Ni, Co, Mn and Cr is 86 mass ppm or more and 260 mass ppm or less,
TiO2-x is 1.5% by mass or more and 1.7% by mass or less,
a maximum value Rmax of a reflectance of a region in a wavelength of 250 nm to 2500 nm is 14.56% or more and 22.44% or less, and
a difference ΔR between the maximum value Rmax and a minimum value Rmin of the reflectance of the region in the wavelength of 250 nm to 2500 nm is 6.18% or more and 13.68% or less.
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