Manufacture of reflecting mirror

Abstract

Abstract PURPOSE:To make the reflectance to light in a prescribed wavelength region variable and to easily obtain desired reflectance by vapor-depositing one or more CeO2 layers at a specified temp. of a substrate in accordance with the desired reflectance when a thin Al layer is formed on the substrate surface and thin film layers of MgF2 and CeO2 are alternately formed on the Al layer by vapor deposition. CONSTITUTION:A thin film layer 11 of high purity Al is formed on a substrate 10 of glass or the like having a smooth surface by a dry coating method, and on the layer 11 thin film layers 12 of MgF2 as layers with lower refractive index and thin film layers 13 of CeO2 as layers with higher refractive index are alternately laid to obtain a reflecting mirror 1 having higher specific reflectance than a mirror having an Al layer 11 alone. When the CeO2 films 13 are vapor-deposited, one or more of the films 13 are deposited while keeping the substrate at a prescribed temp. of 200-400 deg.C in accordance with desired reflectance. As the substrate temp. is raised, the CeO2 layer 13 has higher refractive index. The spectral reflectance depends on temp. under certain wavelengths of light. Thus, the mirror having increased reflectance and capable of varying the reflectance by about 0-7% can be obtd. easily, and the Al layer 11 apt to flaw can be protected.

Inventors

• 👤 Rokuro Watabe

Bibliographic Details