Absolute encoder for linear or angular position measurements
US4786891A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 1986 |
| Grant date | Nov 22, 1988 |
| Priority date | — |
| Expiry date | Apr 8, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/287
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An encoder device of the absolute position type for outputting a shift position or angle of rotation relative to the absolute position. The device comprises a code plate having first and second grid patterns wherein information is stored as 1 or 0 in a periodic manner at pitches slightly different from each other; first and second sensory arrays for detecting the first and second grid patterns; driving means for driving the sensors relative to the grid patterns and for obtaining an alternating signal from each array; and computation means for measuring the phase angle of the alternating signal from each array, and the phase angle difference therebetween and for calculating the position using such phase angles. Advantageously, the invention is suitable for miniaturization due to its simplicity, relaibility, and efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.