Patent · US Expired

Intrusion sensor using optic fiber

US4367460A · kind A · utility

61Cited by
11References
22Claims
0Family size

Inventor

Key dates

Filing dateOct 17, 1979
Grant dateJan 4, 1983
Priority date—
Expiry dateOct 17, 1999

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG08B13/04
  • WIPO fieldControl
  • WIPO sectorInstruments

Abstract

A transparent continuous optical fiber is embedded in a transparent panel made of glass or plastic, with the two ends of the fiber accessible from outside the panel for coupling to a visible or invisible light source and detector respectively. By nearly matching the refractive indices of the panel and the fiber, and using good-quality material for the fiber so that it does not scatter significant amounts of the light passing through it, the fiber can be made virtually invisible although it establishes a complete light circuit. Cutting or breaking through the panel at a point intersecting the fiber interrupts the light circuit and triggers an alarm.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.