Displacement pickup
US6879405B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 10, 2003 |
| Grant date | Apr 12, 2005 |
| Priority date | — |
| Expiry date | Nov 10, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/34794
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A displacement pickup is provided which comprising a scale (12) having defined thereon a first area (12a) where positional information is recorded with a predetermined pitch and a second area (12b) where positional information is recorded with a pitch different from that in the first area (12a), a first reader (10) which reads the positional information recorded in the first area (12a), a first phase detector (14) which detects a first phase on the basis of the positional information read by the first reader (10), a second reader (11) which reads the positional information recorded in the second area (12b), a second phase detector (15) which detects a second phase on the basis of the positional information read by the second reader (11), a phase comparator (16) which makes a comparison between the first and second phases, and an origin signal selector (18) which produce a plurality of signals according to the result of comparison and selects an arbitrary one of the plurality of signals on the basis of the positional information read by the first reader (10).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.