Displacement measuring apparatus
US7808650B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 2008 |
| Grant date | Oct 5, 2010 |
| Priority date | — |
| Expiry date | Jan 21, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/58
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is a displacement measuring apparatus that includes a composite scale having a magnetic pattern and a diffraction grating each aligned in a direction of measuring axis, and a detector head moving in a direction of measuring axis relative to the composite scale. The detector head has a magnetic detection unit detecting a magnetic field exerted by the magnetic pattern to generate first reproduced signals, a light source irradiating the diffraction grating with light, and an optical detection unit detecting the light diffracted by the diffraction grating to generate second reproduced signals. In composite scale, the magnetic pattern and the diffraction grating are arranged such that a pitch of the first reproduced signals is larger than that of the second reproduced signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.