Patent ID: 7905647
Filing Date: 2011-03-15
Classification: G02B,G02F

Abstract:
1. A back light unit comprising: a lamp for generating light; a light guide plate having an incident surface at a side thereof; a prism sheet, disposed opposing an emitting surface of the light guide plate, for condensing the light with a plurality of prism peaks, each prism peak having an inclined angle of 37° with respect to a top surface of the prism sheet, wherein the plurality of prism peaks are formed directly on the top surface of the prism sheet; and a reflecting type polarizer, provided on the prism sheet, for transmitting one of a S-polarization or a P-polarization and reflecting the other of the S-polarization or the P-polarization below, in the light condensed by the prism sheet, wherein the reflecting type polarizer has a full-width half-maximum angle in a luminance angle distribution of 1°; wherein the full-width half-maximum angle is an angle between a virtual vertical line passing through the prim sheet vertically and a direction of the light emitted from the prism sheet; wherein the vertical line is vertical to the top surface of the prism sheet.