Encoder, manufacturing method of encore scale manufacturing method of encoder, and driving apparatus

Abstract

An encoder includes a scale unit having a substrate configured of a metal material and in which a pattern is formed on a first surface of the substrate and a passive state member is formed on a second surface different from the first surface in the substrate, and a detection unit that is configured to move relative to the scale unit and detects the pattern.

1 . An encoder comprising:
 a scale unit having a substrate configured of a metal material and in which a pattern is formed on a first surface of the substrate and a passive state member is formed on a second surface different from the first surface in the substrate; and   a detection unit that is configured to move relative to the scale unit and detects the pattern.   
     
     
         2 . The encoder according to  claim 1 ,
 wherein the first surface is a pattern surface on which the pattern is formed in the substrate, and   wherein the second surface is provided at a side portion of the substrate which is a side surface with respect to the pattern surface.   
     
     
         3 . The encoder according to  claim 1 ,
 wherein the passive state member is formed on the second surface.   
     
     
         4 . The encoder according to  claim 1 ,
 wherein the substrate includes a fixing portion which is fixed to a moving body of a measuring target, and   wherein the passive state member is formed on a surface of the fixing portion.   
     
     
         5 . The encoder according to  claim 1 ,
 wherein the pattern is annularly formed on the first surface.   
     
     
         6 . The encoder according to  claim 1 ,
 wherein the first surface is made capable to reflect light by a mirror surface processing.   
     
     
         7 . The encoder according to  claim 1 ,
 wherein the pattern has a configuration such that a light reflection layer is formed on the first surface, a protective layer having light transparency is formed on the light reflection layer, and a light absorption layer is formed on the protective layer.   
     
     
         8 . The encoder according to  claim 1 ,
 wherein the metal material includes aluminum or an aluminum compound.   
     
     
         9 . The encoder according to  claim 1 ,
 wherein the passive state member is configured of an oxide film.   
     
     
         10 . The encoder according to  claim 9 ,
 wherein the oxide film is an aluminum oxide film.   
     
     
         11 . A manufacturing method of an encoder scale, comprising:
 a passive state member-forming process of forming a passive state member on a second surface different from a first surface on which a pattern is formed in a substrate configured of a metal material;   a pattern layer-forming process of forming a pattern layer on the first surface; and   an etching process which immerses the substrate into an etching solution, removes a portion of the pattern layer, and forms the pattern.   
     
     
         12 . The manufacturing method of an encoder scale according to  claim 11 ,
 wherein the passive state member-forming process includes forming the passive state member on the second surface by a passivation processing.   
     
     
         13 . The manufacturing method of an encoder scale according to  claim 11 ,
 wherein the passive state member-forming process is performed prior to the pattern layer-forming process.   
     
     
         14 . The manufacturing method of an encoder scale according to  claim 11 ,
 wherein the passive state member-forming process includes:   forming the passive state member on a surface including the first surface and the second surface of the substrate; and   removing a portion of the passive state member which is formed on the first surface.   
     
     
         15 . The manufacturing method of an encoder scale according to  claim 11 , further comprising:
 a mirror surface-processing process which performs mirror surface processing on the first surface prior to the pattern layer-forming process.   
     
     
         16 . The manufacturing method of an encoder scale according to  claim 15 ,
 wherein the passive state member-forming process includes:   forming the passive state member on a surface including the first surface and the second surface of the substrate; and   removing a portion of the passive state member which is formed on the first surface, and   wherein the mirror surface-processing process also includes removing the portion of the passive state member formed on the first surface.   
     
     
         17 . A manufacturing method of an encoder, comprising:
 the manufacturing method of an encoder scale according  claim 11 ; and   a detection unit-forming process of forming a detection unit which detects the pattern.   
     
     
         18 . A driving apparatus comprising the encoder according  claim 1 .