Patent ID: 7732753
Filing Date: 2010-06-08
Classification: G02B,G02F

Abstract:
1. An illumination system comprising: a light-transmissive plate, having a first edge surface, a second edge surface, and a light-receiving surface; at least one light source emitting light towards and through the light-transmissive plate, the light entering the light-transmissive plate through the light-receiving surface; a plurality of surface-modification structures disposed at one or more pre-determined locations on the light-receiving surface of the light-transmissive plate, the surface-modification structures diverting a portion of the light impinging upon said structures towards the first and/or the second edge surface of the light-transmissive plate, a first and a second light sensors coupled to the first and the second edge surface of the light-transmissive plate, respectively, for sensing the light diverted at the plurality of surface-modification structures, the light sensors being coupled to a control means for controlling the luminous flux of the at least one light source, wherein the plurality of surface-modification structures comprises first and second surface-modification structures arranged at pre-determined locations on the light-receiving surface of the light-transmissive plate, the first light sensor receiving diverted light substantially exclusively from the first surface-modification structures, and the second light sensor receiving diverted light substantially exclusively from the second surface-modification structures.