Optical position-measuring device having two crossed scales

US8822907B2 · kind B2 · utility

Assignee

• DR. JOHANNES HEIDENHAIN GMBH · DE

Inventors

• Ralph Joerger · Traunstein, DE
• Michael Hermann · Tacherting, DE
• Wolfgang Holzapfel · Obing, DE
• Walter Huber · Traunstein, DE

Key dates

• Filing date: Nov 2, 2011
• Grant date: Sep 2, 2014
• Expiry date: May 4, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B11/2441
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An optical position-measuring device includes a scanning bar extending in a first or second direction, and a scale extending in the other direction. The scale is offset by a scanning distance from the scanning bar in a third direction perpendicular to the first and second directions. The device has a light source whose light penetrates the scanning bar at an intersection point of the scanning bar and scale to fall on the scale and arrive back at the scanning bar. At a detector, the light is split by diffraction into different partial beams at optically effective structures of the scanning bar and scale and combined again. A periodic signal is obtained in the detector in response to: a shift between the scanning bar and scale in the first direction due to interference of combined partial beams, and a change in the scanning distance between the scanning bar and scale.