Optical member

摘要

An optical member has: a transparent substrate; and a dielectric multilayer on the transparent substrate formed by stacking a plurality of unit refractive index layers each formed of a high-refractive index layer having a refractive index of 2 or more and a low-refractive index layer having a refractive index of 1.6 or less. In the optical member, a total number of the unit refractive index layers is 15 or more, and a number of the unit refractive index layers satisfying a condition of nHdH/nLdL≧3 is 10 or more, nHdH represents an optical thickness of the high-refractive index layer, and nLdL represents an optical thickness of the low-refractive index layer.

主权项

1. An optical member, comprising:
a transparent substrate; and a dielectric multilayer provided on the transparent substrate, the dielectric multilayer comprising unit stacks each of which consists of: a high-refractive index layer having a refractive index of 2 or more; and a low-refractive index layer having a refractive index of 1.6 or less and stacked on the high-refractive index layer, wherein each of the unit stacks has an optical thickness ratio (nHdH/nLdL) which is a ratio of an optical thickness of the high-refractive index layer (nHdH) to an optical thickness of the low-refractive index layer (nLdL), wherein a total number of the unit stacks is 15 or more, wherein a number of the unit stacks having an optical thickness ratio of 3 or more is 10 or more, and wherein the dielectric multilayer further comprises at least 5 unit stacks each of which consists of: a high-refractive index layer having a refractive index of 2 or more; and a low-refractive index layer having a refractive index of 1.6 or less and stacked on the high-refractive index layer, the at least 5 unit stacks satisfying in formula: TH/TL≦1.5 where TH represents an average optical thickness of the high-refractive index layers included in the at least 5 unit stacks and, TL represents an average optical thickness of the low-refractive index layers included in the at least 5 unit stacks.