Controlled light extraction from light guides and fibers
First Claim
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1. A method of illuminating an area, comprising the steps of:
- (a) providing at least one elongated light waveguide having a periphery so structured with respect to a core thereof as to enable said core to transmit light along the waveguide while said periphery prevents substantial emanation of light from said core in a direction transverse to said waveguide;
(b) modifying a portion of said periphery over an extraction zone L of said waveguide to impart a generally triangular shape to said zone extending continuously from a narrow end to a wide end thereof and so that light travelling through said core in a propagation direction from said narrow end to said wide end will emanate in an emanation direction transversely to said propagation direction, said zone narrowing in width in a spreading direction transversely to said propagation direction and to said emanation direction whereby an area exposed to said light emanating from said waveguide is illuminated continuously along said length of said zone; and
(c) injecting light into said waveguide ahead of said narrow end so that the light propagates in said propagation direction whereby said area is illuminated.
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Abstract
A controlled emission of light from an optical waveguide, e.g. a fiber into which light is injected at one end, is effected by modifying the periphery of the waveguide over a generally triangular zone so that there is a controlled emission per unit length at every point along this zone and light emanates continuously over the length of the zone from the fiber.
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Citations
20 Claims
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1. A method of illuminating an area, comprising the steps of:
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(a) providing at least one elongated light waveguide having a periphery so structured with respect to a core thereof as to enable said core to transmit light along the waveguide while said periphery prevents substantial emanation of light from said core in a direction transverse to said waveguide; (b) modifying a portion of said periphery over an extraction zone L of said waveguide to impart a generally triangular shape to said zone extending continuously from a narrow end to a wide end thereof and so that light travelling through said core in a propagation direction from said narrow end to said wide end will emanate in an emanation direction transversely to said propagation direction, said zone narrowing in width in a spreading direction transversely to said propagation direction and to said emanation direction whereby an area exposed to said light emanating from said waveguide is illuminated continuously along said length of said zone; and (c) injecting light into said waveguide ahead of said narrow end so that the light propagates in said propagation direction whereby said area is illuminated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for illuminating an area which comprises:
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at least one elongated light waveguide extending in juxtaposition with said area and having a periphery so structured with respect to a core thereof as to enable said core to transmit light along the length of the waveguide while said periphery prevents emanation of light from said core in a direction transverse to said waveguide, a portion of said periphery over an extraction zone of a length L of said waveguide imparting a generally triangular shape to said zone extending continuously from a narrow end to a wide end thereof and so that light travelling through said core in a propagation direction from said narrow end to said wide end will emanate in an emanation direction transversely to said propagation direction, said zone varying in width in a spreading direction transversely to said propagation direction and to said emanation direction whereby an area exposed to light emanating from said waveguide is illuminated continuously along said length; and means for injecting light into said waveguide ahead of said narrow end so that the light propagates in said propagation direction. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method of illuminating an area, comprising the steps of:
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(a) providing at least one elongated light waveguide having a periphery so structured with respect to a core thereof as to enable said core to transmit light along the waveguide while said periphery prevents substantial emanation of light from said core in a direction transverse to said waveguide; (b) modifying a portion of said periphery over a continuous elongate zone of said waveguide having a shape and a width or refractive index selected so that light travelling through said core in a propagation direction along the length of said zone will emanate in an emanation direction transversely to said propagation direction in an intensity dependent upon the shape, width or refractive index to illuminate an area exposed to said light emanating from said waveguide continuously along said length of said zone at a predetermined rate; and (c) injecting light into said waveguide ahead of said narrow end so that the light propagates in said propagation direction whereby said area is illuminated.
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19. A device for illuminating an area which comprises:
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at least one elongated light waveguide extending in juxtaposition with said area and having a periphery so structured with respect to a core thereof as to enable said core to transmit light along the length of the waveguide while said periphery prevents emanation of light from said core in a direction transverse to said waveguide, a portion of said periphery over an elongate continuous extraction zone of said waveguide imparting a selected shape, width and refractive index to said zone so that light travelling through said core in a propagation direction along a length of the zone will emanate in an emanation direction transversely to said propagation direction, said zone having a shape, width and refractive index selected to illuminate an area exposed to light emanating from said waveguide at a predetermined rate per unit length of the zone; and means for injecting light into said waveguide ahead of said narrow end so that the light propagates in said propagation direction.
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20. A method of illuminating an area, comprising the steps of:
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(a) providing at least one elongated light waveguide having a periphery so structured with respect to a core thereof as to enable said core to transmit light along the waveugide while said periphery prevents substantial emanation of light from said core in a direction transverse to said waveguide; (b) varying a refractive index of a portion of said periphery over a fixed continuous elongate zone so that the refractive index of said portion is less than that of said core and that light travelling through said core in a propagation direction along the length of said zone will emanate in an emanation direction transversely to said propagation direction in an intensity dependent upon the variation in the refractive index to illuminate an area exposed to said light emanating from said waveguide continuously along said length of said zone at a predetermined rate; and (c) injecting light into said waveguide ahead of said narrow end so that the light propagates in said propagation direction whereby said area is illuminated.
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Specification