Capacitive sensing scheme for digital control state detection in optical switches
US6788520B1 · kind B1 · utility
Inventors
Key dates
| Filing date | Nov 28, 2000 |
| Grant date | Sep 7, 2004 |
| Priority date | — |
| Expiry date | Mar 29, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/357
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is an apparatus and method for detecting whether rotatable MEMS elements are in the “on” or “off” position. Embodiments of the invention have application in devices switches that employ mirrors that move between an “on” or “off” position, wherein they reflect light from an input fiber into an output fiber in the “on” position, and allow the light to pass in the “off” position. Electrodes are positioned in the device such that the mirrors are close to, and therefor capacitively coupled to, a different electrode depending on whether they are in the “on” or “off” position. This invention is especially useful for switches that already employ electrodes for electrostatic clamping of mirrors in one or more positions, since those same electrodes can be used both to electrostatically clamp the mirrors and to sense their position. The method described in this invention comprises sensing of the capacitance between the mirrors and the one or more electrodes used to clamp the mirrors in its one or more position in order to detect which of the positions the mirrors are clamped in. Furthermo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.