Patent ID: 8668372

Claim:
An illumination device comprising: a substrate at least partially transparent and transmissive to light and having a refractive index, n s ; an anti-resonant reflecting optical waveguide structure defining a first surface for being disposed adjacent a first substance having a refractive index, n 0 , a second surface opposite the first surface and disposed adjacent and in contact with the substrate, and a perimetrical edge; and at least one light source positioned along at least a portion of the perimetrical edge for entry of light into the waveguide structure via the perimetrical edge, wherein the waveguide structure comprises: a core material at least partially transparent and transmissive to light impinging one or more of the first surface and the second surface, the core material comprising: a first layer defining the first surface, the first layer having an opposing surface opposite the first surface, and a thickness, d 1 , the first layer comprising a first transparent material having a refractive index, n 1 , configured to be greater than a refractive index, n 0 , of an adjacent first substance for total internal reflection at the first surface of the light entering from the perimetrical edge; a second layer defining the second surface, the second layer having an opposing surface opposite the second surface, and has a thickness, d 3 , the second layer comprising a second transparent material having a refractive index, n 3 , less than the refractive index, n s , of the substrate for dispersion of a portion of the light entering from the perimetrical edge through the second surface and into the substrate; and an anti-resonant layer disposed between the first layer and the second layer in contact with the opposing surfaces of both the first layer and the second layer, the anti-resonant layer having a thickness, d 2 , and comprising a transparent material layer having a refractive index, n 2 , greater than the refractive indexes, n 1 and n 3 , of both the first layer and the second layer, and the core material is configured according to the formulae, d 2 ≈ 1 ⁢ λ 4 ⁢ n 2 ⁢ ⁢ ( 1 - ( n 1 n 2 ) 2 + ( λ 2 ⁢ n 2 ⁢ d 1 ) 2 ) - 1 / 2 ⁢ and d 3 ≈ 1 ⁢ λ 4 ⁢ n 3 ⁢ ( 1 - ( n 1 n 3 ) 2 + ( λ 2 ⁢ n 3 ⁢ d 1 ) 2 ) - 1 / 2 , where λ is a central wavelength of the spectrum of light from the at least one light source, d 1 >λ/n 1 , n 1 equals n 3 and d 1 is approximately 2d 3 .