Position measuring system with a scanning unit having a reference pulse signal detection unit

US7348546B2 · kind B2 · utility

Assignee

• DR. JOHANNES HEIDENHAIN GMBH · DE

Inventors

• Jürgen Schoser · St. Georgen, DE
• Michael Hermann · Tacherting, DE
• Wolfgang Holzapfel · Obing, DE

Key dates

• Filing date: Feb 9, 2006
• Grant date: Mar 25, 2008
• Expiry date: Mar 14, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/2457
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A position measuring system having a scale that includes an incremental graduation track, which extends in a measuring direction, the incremental graduation track having a periodic arrangement of graduation areas with different optical properties and a reference marking in a reference position, which has an aperiodic arrangement of graduation areas. A scanning unit including a light source and an opto-electronic detector arrangement having a reference pulse signal detection unit for generating a reference pulse signal. A periodic strip pattern results in a detection plane, which is amplitude-modulated in an area of the reference position, wherein the reference pulse signal detection unit includes several reference pulse signal detection elements, which create the reference pulse signal so that a periodic signal portion, as well as low-frequency signal portions are filtered out of the incremental graduation track to a large degree.