Emission device, surface light source device, display and light flux control member

摘要

A display has a member irradiated by a surface light source device comprising a light diffusion member and emission device. The emission device is provided with a light flux control member having a recess and light control emission face which is configurated so as to satisfy Conditions 1 and 2 in a range at least covering a half-intensity-angular-range. Light emitting element(s) may be sealed. Condition 1 is that relation theta 5/theta1 >1 is satisfied except for light emitted from a light emitting element toward within an angular-neighbourhood of a standard optical axis of the emission device, and Condition 2 is that value of theta 5/theta1 decreases gradually according to increasing of theta 1 , where theta 1 is an emission angle of any light at being emitted from the light emitting element, and theta 5 is an emission angle of that light of theta 1 at then being emitted from the light control emission face of the light flux control member.