Spectral Reflectometer

Abstract

A spectral reflectometer includes a first substrate, a first light emitting element and a second light emitting element in which a height of a first light emitting portion which is the height from the first substrate to a first light emitting portion of the first light emitting element, which is installed on the first substrate and a height of a second light emitting portion which is the height from the first substrate to a second light emitting portion of the second light emitting element are different, and a light receiver that receives light, in which the second light emitting element having a high height of the second light emitting portion is installed at a position close to an optical axis of the light received by the light receiver from the first light emitting element having a low height of the first light emitting portion.

Dependencies are inferred from the claim text.