Reflection-type optical encoder scale including an inorganic layer stack pattern with specific reflectance

Abstract

A main object of the present disclosure is to provide a reflection-type optical encoder scale capable of sufficiently reducing the reflectance on a low reflection region. The present disclosure achieves the object by providing a reflection-type optical encoder scale comprising: a high reflection region and a low reflection region alternately placed on a transparent substrate, wherein the low reflection region includes a low reflection portion including at least three stacked inorganic layers, and a reflectance on the low reflection region is 5% or less, wherein the high reflection region includes at least one stacked inorganic layer, and a reflectance on the high reflection region is 60% or more, and wherein a value of a ratio S/N represented by the following formula (3) is 6 or more, (3) the ratio S/N=the reflectance on the high reflection region/the reflectance on the low reflection region.