Intrusion sensor using optic fiber
First Claim
1. An intrusion sensor for use with an optical source and detector, and comprising:
- a substantially transparent and solid panel; and
a unitary optic fiber at least partly embedded in the panel and having each of its two ends near a surface of the panel;
wherein the panel and the portion of the fiber in contact therewith each have respective refractive indices, and the difference between the said respective refractive indices is sufficiently small to render the fiber substantially invisible to the eye; and
the two ends are adapted, located and oriented for optical coupling of such optical source to such optical detector.
1 Assignment
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Accused Products
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.
96 Citations
22 Claims
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1. An intrusion sensor for use with an optical source and detector, and comprising:
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a substantially transparent and solid panel; and a unitary optic fiber at least partly embedded in the panel and having each of its two ends near a surface of the panel; wherein the panel and the portion of the fiber in contact therewith each have respective refractive indices, and the difference between the said respective refractive indices is sufficiently small to render the fiber substantially invisible to the eye; and the two ends are adapted, located and oriented for optical coupling of such optical source to such optical detector. - View Dependent Claims (2, 4, 5, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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3. An intrusion sensor for use with an optical source and detector, and comprising:
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a substantially transparent and solid panel; and a unitary optic fiber at least partly embedded in the panel and having each of its two ends near a surface of the panel; wherein the panel and the portion of the fiber in contact therewith each have respective refractive indices, and the difference between the said refractive indices is sufficiently small to render the fiber substantially invisible to the eye but is also sufficiently large to maintain adequate internal reflection within the fiber and thus adequate optical transmission through the fiber from one end to the other; and the two ends are adapted, located and oriented for optical coupling to such optical source and detector, respectively.
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6. An intrusion sensor for use with an optical source and detector, and comprising:
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a substantially transparent and solid panel; and a unitary optic fiber at least partly embedded in the panel and having two ends; wherein the panel and the portion of the fiber in contact therewith each have respective refractive indices, and the difference between the said respective refractive indices is sufficiently small to render the fiber substantially invisible to the eye; and the two ends of the fiber are adapted, located and oriented for optical coupling of such optical source to such optical detector. - View Dependent Claims (8, 9, 10, 11)
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7. An intrusion sensor for use with an optical source and detector, and comprising:
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a substantially transparent and solid panel; and a unitary optic fiber at least partly embedded in the panel and having two ends; wherein the panel and the portion of the fiber in contact therewith each have respective refractive indices, and the difference between the said refractive indices is sufficiently small to render the fiber substantially invisible to the eye but is also sufficiently large to maintain adequate internal reflection within the fiber and thus adequate optical transmission through the fiber from one end to the other; and the two ends are adapted, located and oriented for optical coupling to such optical source and optical detector, respectively.
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Specification