Optical position-measuring device having grating fields with different step heights

US10119802B2 · kind B2 · utility

Assignee

• DR. JOHANNES HEIDENHAIN GMBH · DE

Inventors

• Peter Speckbacher · Kirchweidach, DE
• Tobias Gruendl · Hausham, DE
• Christian Baeuml · Traunwalchen, DE
• Josef Weidmann · Feichten, DE

Key dates

• Filing date: Jan 20, 2017
• Grant date: Nov 6, 2018
• Expiry date: Jan 20, 2037

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B2290/65
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An optical position-measuring device includes a scale and a scanning reticle, whose relative position is determinable in three linearly independent spatial directions using interfering light beams. A splitter grating is disposed on the scanning reticle and adapted to split light into sub-beams of different diffraction orders. An optical grating is disposed on the scale and adapted to further split the sub-beams and to recombine them after they have been reflected back from the scanning reticle. Grating fields configured as phase gratings are disposed on a side of the scanning reticle that faces the scale. The grating fields act as diffractive optics that influence the further split sub-beams. The grating fields have different step heights. An output grating is disposed on the scanning reticle and adapted to output, as interfering sub-beams, light that has been multiply reflected between the scale and the scanning reticle.