| 摘要 |
PURPOSE:To enhance power consumption-brightness conversion efficiency and to obtain high brightness by arranging a sheet made of translucent material having a lot of prescribed projections at a minute interval on the same surface of a light-emitting surface side so that the projection surface is faced to the outside. CONSTITUTION:A light source 1 is provided, and the sheet 7 made of translucent material whose light-emitting surface has a lot of the projections having a vertical angle having the same shape parts substantially at a minute interval, and in such a manner, by arranging it so that the projection surface is faced to the outside, directivity of a beam outgoing from a plane shape light-emitting body is changed, and the directivity in the vicinity of a normal direction drawn to the light-emitting surface is intensified more, and a sheet or plural sheets of the sheets 7 are used. Further, the shape of the projection formed on the sheet is a so-called prism shape having two or more of optical planes, and may be a many-sided pyramid of a trigonal pyramid a tetragonal pyramid or a cone. Further, the projections whose vertical angles have the same shapes substantially, that is, the vertical angles of a cutting surface containing vertexes obtained under the same condition have the same angle substantially. |
