Emission device with light source and light flux control member

摘要

An emission device (29) adapted for use in a surface light source device (2) that comprises a plurality of such emission devices has a light flux control member (5) provided with a recess (10) and a light control emission face (6), and a light-emitting element (4) capable of being accommodated in the recess (10). Light emitted from the light-emitting element (4) emerges from the light control emission face (6) after travelling within the light flux control member (5). The light control emission face (6) is configured so as to satisfy the following Conditions 1 and 2, at least for light which is emitted forwards within a half-intensity angular range around a maximum-intensity emission direction of the light-emitting element (4):
€¢ Condition 1: ¸5/¸1>1 is satisfied except for light emitted forwards within an angular neighbourhood of a standard optical axis (L) of the emission device;
€¢ Condition 2: The value of ¸5/¸1 decreases gradually as ¸1 increases;
where ¸1 is the emission angle of light emitted from the light-emitting element (4), this light emerges from the light control emission face (6) of the light flux control member (5), and ¸5 is the emission angle at which it emerges. The light-emitting element (4) is mounted on a substrate (12) to which the light flux control member (5) is fixed. Such an arrangement leads to uniform light emission.