Patent ID: 7302156

Claim:
An optical system comprising: at least one optical fiber having a core and cladding, said at least one optical fiber extending along at least most of a periphery of a light curtain area, said at least one optical fiber having a cross section defining a circumference, said at least one optical fiber having at least one light scattering discontinuity at at least one location therealong, said at least one optical fiber having optical power at at least one light transmissive region having a focus located in proximity to said discontinuity, said at least one light scattering discontinuity extending along said periphery, said at least one light scattering discontinuity having an angular extent of less than ten percent of said circumference and said at least one light transmissive region having an angular extent of more than 25% of said circumference; and a light source arranged for directing light along said at least one optical fiber, said optical power of said at least one optical fiber at said at least one light transmissive region and said at least one light scattering discontinuity being operative to direct light, received from said light source along said at least one optical fiber and scattered by said at least one light scattering discontinuity, directly from said at least one discontinuity through said cladding, generally in a plane extending in a direction generally away from said at least one discontinuity, filling the interior of said periphery and thereby defining a light curtain therewithin.