| 摘要 |
PROBLEM TO BE SOLVED: To provide an light emitting device with its light emitting efficiency further improved. SOLUTION: A window is equipped with a side face having a 1st partial area vertical to a primary surface and a 2nd partial area oblique to the same. The 1st area forms an edge together with the primary surface and is away from the primary surface by a distance d changing gradually into the 2nd area, and the boundary of the radially formed plane in its lateral direction is positioned with a distance l from the edge formed by the 1st area and the primary surface. In this context, l>=d/tanβ, wherein β=arccos (n1 /n2 ), wherein n1 is the refraction factor of the multilayer structure, n2 is the refraction factor of the window, and n1 <n2 . |
