Patent ID: 8672522

Claim:
An optical sheet, comprising a structured layer, which is a resin-cured layer having a structured surface; and a substrate layer formed to be in contact with the structured layer, wherein, when the structured surface is loaded up to a maximum pressure of 5 g f at a loading rate of 2.648 mN/sec using a flat indenter, in which a shape of a surface of the indenter coming into contact with the structured surface is circular and which has a diameter of 50 μm, held at the maximum pressure for 5 sec, and then unloaded, a difference (D 2 ) between a height of the sheet after being unloaded and an original height of the sheet before being loaded satisfies Expression 1 below: D 2 D/120 Expression 1 wherein D is the height of the optical sheet before being loaded; and wherein said substrate layer has a thickness of 188 μm±2 μm.