Prism Sheet and Production Method thereof and Surface Light Source Device

摘要

A prism sheet provided with an elongated prism formed surface (41) on which a plurality of elongated prisms (411) extend in parallel to each other. The elongated prism formed surface (41) has roughened portions (412) each having a width W 0.04 to 0.5 times the arranging pitch P of the elongated prisms and arranged between adjacent elongated prisms (411). The surface of the roughened portion (412) has a center-line average roughness Ra of 0.3-2 mum and a ten-point average roughness Rz of 1-3 mum, and the prism surface (411a, 411b) of elongated prism has a center-line average roughness Ra of less than 0.3 mum and a ten-point average roughness Rz of less than 1 mum.