Patent ID: 8613540

Claim:
A light guide plate having reduced hot spots comprising: an input surface for receiving light from a plurality of discrete light sources, an output surface for emitting light, a bottom surface opposing to the output surface, and an end surface opposing to the input surface, wherein the direction from the input surface to the end surface is defined as Y-axis, the direction that is perpendicular to the Y-axis and parallel to the discrete light sources is defined as X-axis, the output surface has a plurality of elongated grooves running parallel to the Y-axis and extending from the input surface corresponding to Y=0 to the end surface, the bottom surface has a core zone extending from a predetermined line corresponding to Y=Y 1 to the end surface and a mixing zone extending from Y=0 to Y=Y 1 ; and a set of lenses are distributed in the core zone and a set of micro-lenses distributed in the mixing zone between Y=Y 0 and Y=Y 1 , wherein the density of the set of micro-lenses varies in the X-axis, having a maximum value at a first location that has a same X value as the center of one of the discrete light sources, and having a minimum value at a second location that has a same X value as the center of two adjacent discrete light sources, and the selected size and the density of the micro-lenses redirect the light from the discrete light sources toward the Y-axis and the ratio L 1 /L 0 is between 0.9 and 1.1 for any Y≧Y 1 ; wherein L 1 is the light flux along a line that passes midway between the center of two adjacent light sources and L 0 is the light flux along a line that passes through the center of a light source.