Fiber optic thermal switch utilizing frustrated total internal reflection readout
US5031987A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 2, 1990 |
| Grant date | Jul 16, 1991 |
| Priority date | — |
| Expiry date | Jan 2, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/3576
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A fiber optic transducer utilizes a single optical fiber having one end surface, disposed adjacent a sensor element, cut at an angle to result in frustrated total internal reflection. The end surface of the optical fiber is spaced away from the sensor element. As the sensor element is displaced with respect to the end surface of the optical fiber, the amount of light reflected from the sensor element varies. Light injected into the optical fiber is reflected back toward the light source until the element comes into relatively close proximity with the angled end of the optical fiber. When this occurs, a portion of the light is transmitted across the gap and absorbed by the sensor element. The ratio of the light reflected from the reflective surface to the total light input into the optical fiber produces a signal representative of the displacement of the sensor element. This signal can then be converted to a corresponding temperature or pressure signal and displayed at a remote location. The transducer is capable of being used with temperature or pressure sensitive elements to provide either an analog output signal or a digital output signal. Also disclosed is a self test circuit fo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.