JPS6447079A - Optical functional device - Google Patents

Abstract

PURPOSE:To increase adhesion to a substrate and to improve reproducibility of spectral transmittance characteristics and wave length characteristics by interposing a yttrium oxide between a substrate of Bi-Ge-O single crystal or Bi-Ge-O single crystal and a transparent conductive film. CONSTITUTION:Yttrium oxide films 2, 2 are formed each on the both sides of a single crystal substrate 1. A crucible 16 is heated in a vacuum chamber 11. Light from a light source 13 is transmitted to a transmitting window 12u, a monitor glass 15 and a yttrium oxide film 2; then the modulated light thereby is transmitted through a transmitting window 12d and injected to a photosensor 14 and converted to electric signal corresponding to light intensity of the modulated light. The film thickness d1 of the film 2 is usually set to satisfy a formula (1); where, n1:yttrium oxide refraction factor, d1:film thickness of yttrium oxide and lambda:wavelength. Similarly, a transparent conductive films 3, 3 such as indium oxide film are evaporated to a desired thickness. The film thickness d2 of the conductive film 3 is given by a formula (2) where n2 is refraction factor of indium oxide.