# 17-24-088

spectral internal transmittance, <of a homogeneous non-diffusing layer>

τi (λ)

quotient of the spectral radiant flux reaching the exit internal surface of the layer and the spectral flux that enters into the layer after crossing the entry surface

Note 1 to entry: For a given layer the spectral internal transmittance depends on the path length of the radiation in the layer, and hence, in particular, on the angle of incidence.

Note 2 to entry: The spectral internal transmittance has unit one.

Note 3 to entry: This entry was numbered 845-04-81 in IEC 60050-845:1987.

Note 4 to entry: This entry was numbered 17-1215 in CIE S 017:2011.

Publication date: 2020-12