Patent ID: 7618164
Filing Date: 2009-11-17
Classification: F21V,G02B,G02F

Abstract:
1. An optical substrate, comprising: a base; a planar light input surface at one side of the base; and a light output surface extending from another side of the base, wherein the light output surface is opposite to the light input surface, said light output surface being a three-dimensionally varying structured surface represented by a plurality of prisms, which includes irregular prisms, each defining a peak, wherein the plurality of prisms are arranged in longitudinal rows, wherein the longitudinal rows are arranged side by side in a lateral direction, forming a valley between two adjacent longitudinal rows of prisms, wherein each longitudinal row of prisms comprises longitudinally and directly contiguously adjoining prisms, having directly contiguous ends with a directly contiguous interfacing plane present between the directly contiguous ends of the adjoining prisms, wherein each irregular prism includes a generally longitudinally tapering body having a first end and a second end, and the peak extending from the first end to the second end, and wherein the plurality of prisms have physical geometries and dimensions that vary in a random manner at least along each row over an area of the structured surface, wherein said each row is not symmetrical lengthwise about a mid point in the respective rows.