PRISM SHEET AND LIGHT SOURCE UNIT USING SAME, AND LIQUID CRYSTAL DISPLAY UNIT

摘要

PROBLEM TO BE SOLVED: To obtain the prism sheet which has luminance unevenness improved and can converge light to the front by using a prism sheet which has prism parts sectioned in scalene triangles each having specific base length. SOLUTION: The prism sheet is divided roughly into the prism part 1 and a base part 2. The prism part 1 has many linear prisms which have scalene- triangular vertical section preferably so that adjacent linear prisms are in contact with each other and the corresponding surfaces of the linear prisms are parallel to each other while the length of each scalene triangle is 20-140μm. Further, the shape of the scalene triangles varies with the extent of luminance unevenness of a back light when an edge light type back light is used, but the angle between one side and the base of the triangle is preferably 45-70 deg. and the angle between the other side and base is preferably 65-80 deg..