Patent ID: 7845810
Filing Date: 2010-12-07
Classification: G02B,G02F

Abstract:
1. A prism sheet for a direct backlight, comprising: a light input surface; a light output surface opposite to the light input surface; and a plurality of micro-protrusions formed on the light output surface and arranged and aligned in a skewed matrix, the skewed matrix comprising rows and columns, the rows forming a plurality of first circular arcs having a predetermined S-shaped curvature, and the columns forming a plurality of second circular arcs having a predetermined S-shaped curvature, wherein each micro-protrusion includes four side surfaces connected to each other, a transverse width of each side surface decreases along a direction away from the light output surface; each micro-protrusion has a shape that follows a contour defined by the rows and columns of the skewed matrix, a pair of side surfaces of each micro-protrusion being formed along the first circular arcs and the other pair of side surfaces being formed along the second circular arcs; the first circular arcs are smooth, continuous, and coplanar with the light output surface, and the second circular arcs are smooth, continuous, and coplanar with the light output surface.