Patent ID: 6072551
Filing Date: 2000-06-06
Classification: G02B,G02F

Abstract:
A backlight apparatus comprising:a collimating waveguide having a light input end, a top surface, a bottom surface, opposing sides, and a total internal reflection critical angle;a plurality of first facets in said bottom surface distributed in a direction along said collimating waveguide away from said light input end and extending at least part way between said opposing sides;each of said first facets having a first facet bottom surface converging toward said top surface in a direction away from said light input end;a plurality of second facets in said bottom surface distributed in a direction along said backlight apparatus away from said light input end and extending at least part way between said opposing sides, each of said plurality of second facets interleaved alternately between said plurality of first facets;a reflective layer disposed only on each of said first facet bottom surfaces to prevent light from leaking from each of said first facet bottom surfaces; andwherein said first facet bottom surfaces cause light rays entering said light input end and having an angle near said total internal reflection critical angle to exit said top surface at an angle nearly tangential to said top surface.