Patent ID: 8251547
Filing Date: 2012-08-28
Classification: F21V,F21Y,G02B,G02F,H01L

Abstract:
1. An emission device comprising: at least one point-like-light-source; and a light flux control member having a back face to which an output light flux of said point-like-light-source is incident before undergoing propagation within said light flux control member and an emission face which is opposite to said back face and outputs illumination light forming a three-dimensional emission flux in a traveling direction and a center of which is defined as a reference optical axis, wherein said emission face includes a light control emission face controlling the emission of said illumination light, and said back face includes a first recess portion which is formed at a location corresponding to said point-like-light-source as to be capable of introducing a part of said light fluxes of said point-like-light-source into said light flux control member and at least one second recess portion which is located in an area surrounding an opening-edge of said first recess portion as to be capable of introducing another part of said light fluxes of said point-like-light-source into said light flux control member, said second recess portion being configured as to be capable of restraining refraction on incidence of light of said point-like-light-source to said second recess portion from generating inner-propagation light having a traveling direction approaching said reference optical axis, said light control emission face being configured as to meets the following conditions (a), (b) and (c) regarding light emitted in a direction range which is at least within 75° from a maximum intensity light emission direction of said point-like-light-source, so far as out of a neighbor of said reference optical axis, under a definition such that θ (a) {θ (b) θ (c) increasing quantity of θ said second recess portion having a triangle-like cross section shape on a plane on which said reference optical axis extends, and having a ring-like first slope adjacent to said first recess portion and a ring-like second slope which is located outside of said ring-like first slope and connects an end portion of said first slope with said back face, said first slope being formed as to either extend on an extended part of the straight line running between an emission center of said point-like-light-source and other end portion of said first slope, or be formed at an inclination angle larger than an inclination angle of said extended part of the straight line with respect to a general plane of said back face so that light which has reached said second recess portion after being emitted from said point-like-light-source is not hindered from being incident to said second slope.