Patent ID: 8369678

Claim:
An optical device for guiding illumination comprising: a body having a first surface and a second surface, each of said first and second surfaces being on opposite sides of the body, in which said first surface has a plurality of ramp structures, said body has an optical axis extending along a dimension parallel to said second surface; and each of said ramp structures having a ramp surface at a first acute angle with respect to said optical axis, a front exit face following said ramp surface at a second acute angle with respect to the normal of said optical axis, in which light when inputted at one end of said body is substantially totally internally reflected within said body until exiting said body through the front exit face of two or more of said ramp structures, wherein NA is the numerical aperture of the light inputted said one end of said device, and said NA and said second acute angle are in inverse relationship with each other.