Scale assembly for optical encoder having affixed optical reference markers

US7343693B2 · kind B2 · utility

Assignee

• The GSI Group, LLC · US

Inventors

• Donald K. Mitchell · Tulsa, US
• Donald L. Grimes · Milford, US
• William G. Thorburn · Northbridge, US
• Stuart A. Dodson, II · Waltham, US
• Keith M. Hinrichs · Natick, US
• Andrew Goldman · Bet Shemesh, IL
• Joel Mikael Petersen · Burbank, US
• Christopher Chapman Rich · Rancho Palos Verdes, US

Key dates

• Filing date: Nov 9, 2006
• Grant date: Mar 18, 2008
• Expiry date: Nov 9, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/366
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A flexible optical marker is applied to an optical scale substrate to make an optical scale assembly for an optical position encoder. The marker may be a limit marker, index marker, or other type of marker. The marker substrate may be a plastic film such as polyester, singulated from a “recombine” roll created by a web process. The marker has a microstructured pattern on one surface that is covered with a reflective metal coating. The marker also has an adhesive layer and is affixed to the optical scale substrate by a process of aligning the marker to an edge of the scale and then applying pressure to the upper surface of the marker. The marker may be applied with a handle portion that is separated from the marker after the marker is affixed. The marker may be especially useful with a flexible scale substrate such as a metal tape substrate. By affixing the marker to the scale substrate as a separate step of making an encoder scale, various benefits such as reduced inventory, cost, and lead time may be achieved.