Sheet and light-emitting device

Abstract

A transparent sheet for use with a light emitting body with one of surfaces of the transparent sheet being adjacent to the light emitting body, wherein the other surface of the sheet is divided into a plurality of minute regions δ, a largest inscribed circle of the minute regions δ having a diameter from 0.2 μm to 1.5 μm, each of the minute regions δ being adjoined by and surrounded by two or more other ones of the plurality of minute regions δ, the plurality of minute regions δ include a plurality of minute regions δwhich are randomly selected from the plurality of minute regions δ so as to constitute 40% to 98% of the minute regions δ and a plurality of minute regions δwhich constitute the remaining portion of the minute regions δ, the minute regions δare provided with a first tiny element which has thickness d and effective refractive index n, and the minute regions δare provided with a second tiny element which has thickness d and effective refractive index n, nbeing greater than n.