Patent · US Active

Position-measuring device

US9677874B2 · kind B2 · utility

2Cited by

7References

13Claims

0Family size

Assignee

DR. JOHANNES HEIDENHAIN GMBH · DE

Inventors

Peter Speckbacher · Kirchweidach, DE
Tobias Gruendl · Hausham, DE
Josef Weidmann · Feichten, DE
Andrew Graham · Ambler, US
Daniela Bayer · Nußdorf, DE

Key dates

Filing date	Jan 25, 2016
Grant date	Jun 13, 2017
Priority date	—
Expiry date	Jan 25, 2036

Classification

Technology area (CPC G)Physics
CPC primaryG01D5/34746
WIPO fieldMeasurement
WIPO sectorInstruments

Abstract

A position-measuring device includes a first scale and a second scale, which are arranged end-to-end to extend across a measurement range, as well as a scanning unit having a light source configured to emit a light beam. The first scale includes a reflective phase grating having first periodic marks which diffract an incident light beam into a predetermined diffraction order with a first diffraction efficiency. The second scale includes a reflective phase grating having second periodic marks that differ in shape from the first periodic marks. A reflectivity of the phase grating of the second scale is reduced compared to a reflectivity of the phase grating of the first scale to such an extent that the phase grating of the second scale diffracts the incident light beam into the predetermined diffraction order with the first diffraction efficiency.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.