Position sensor and circuit for optical encoder
US6528783B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 7, 2001 |
| Grant date | Mar 4, 2003 |
| Priority date | — |
| Expiry date | Sep 7, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06G7/22
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electronic circuit for measuring the position of a spatially periodic intensity pattern of incident radiation includes an array of detectors (1); two or more correlator units (2, 3) each having arrays of capacitors (12, 13) connected to a buffer (14); and a phase angle computing unit (4). The pitch of the array of detectors (1) is smaller than the pitch of the incident intensity pattern so that the latter is oversampled, yielding high accuracy. The detector outputs (17) are weighted by respective fixed capacitance values (15, 16) which vary periodically along arrays of capacitors (12, 13), and a weighted sum of outputs for each correlator unit (2, 3) is output at its respective buffer (14). The capacitance values (15, 16) of respective correlator units (2, 3) are mutually offset by a predetermined phase shift. The analog computation using capacitor arrays (12, 13) is fast and energy efficient, and can be implemented as a VLSI circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.