DISPLACEMENT SENSOR AND METHOD OF MAKING TARGET FEATURE THEREFOR

摘要

PROBLEM TO BE SOLVED: To accurately measure a displacement of an object by a method wherein a target feature is mounted on the object, an incident light beam is made to reflect on the target feature and a first image thus formed is received by an imaging lens to be reformed on a photodetector as a second image of a light source. ;SOLUTION: A target feature 16 is mounted on an object 14 or formed integral with the object 14. An incident light beam 12 is generated by a light source 10 and is made to reflect on the target feature 16 to generate the reflected light beam 18. A reflection surface slightly curved of the target feature 16 causes the light source 10 to create a dot-like or linear image. With the movement of the target feature 16, the first image moves. The reflected light beam 18 is focused by an imaging lens 26 to form a second image of the light source 10 on a photodetector 20. A processing circuit receives an electrical signal generated by the photodetector 20, thereby enabling determination of the position and/or a displacement from a known reference position of the object 14.;COPYRIGHT: (C)1999,JPO