Photoelectric position measuring system that optimizes modulation of a scanning device and the intensity of a reference mark signal

US6472658B2 · kind B2 · utility

Assignee

• DR. JOHANNES HEIDENHAIN GMBH · DE

Inventors

• Elmar Mayer · Nußdorf, DE
• Wolfgang Holzapfel · Obing, DE
• Andreas Franz · Ludwigsburg, DE

Key dates

• Filing date: Apr 9, 2001
• Grant date: Oct 29, 2002
• Expiry date: Apr 9, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/38
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An incremental position measuring system in the form of a three-grating sensor is optimized in such a way, that the degree of modulation (M) of the incremental scanning device, as well as the intensity (I) of a reference marker signal are relatively strong. To this end, a phase grating with an effective phase deviation of &lgr;/4 is embodied on a scale 2, as well as a reference marker (R) in the form of an amplitude structure. A compact structure is achieved by the divergent illumination of the grating located in front of the scale.