Patent ID: 8491160

Claim:
A transparent sheet usable in the state where one of surfaces thereof is adjacent to a light emitting body, wherein: the other surface of the sheet is divided into a plurality of tiny areas δ having such a size that a maximum circle among circles inscribed thereto has a diameter of 0.5 μm or greater and 3 μm or less, and one of the tiny areas δ is adjacent to, and surrounded by, others of the plurality of tiny areas δ; the plurality of tiny areas δ include a plurality of tiny areas δ 1 randomly selected from the plurality of tiny areas δ, and the remaining plurality of tiny areas δ 2 ; the plurality of tiny areas δ 1 each include an area δ 1a along a border with the corresponding tiny area δ 2 , and the remaining area δ 1b ; the plurality of tiny areas δ 2 each include an area δ 2a along a border with the corresponding tiny area δ 1 , and the remaining area δ 2b ; the tiny areas δ 1b each protrude upward from a prescribed reference plane parallel to the other surface of the sheet by a height of d/2 toward the other surface; the tiny areas δ 1a each protrude upward from the reference plane by a height of zero to d/2 toward the other surface; the tiny areas δ 2a are each recessed downward from the reference plane by a depth of d/2 away from the other surface; the tiny areas δ 2b are each recessed downward from the reference plane by a depth of zero to d/2 away from the other surface; the reference plane is located at an intermediate position, in a direction perpendicular to the other surface of the sheet, between the tiny areas δ 1b and the tiny areas δ 2a ; and d is 0.2 μm or greater and 3.0 μm or less.