| 摘要 |
PROBLEM TO BE SOLVED: To provide a luminous flux control member capable of improving utilization efficiency of light emitted from a light emitting element.SOLUTION: The luminous flux member related to the present invention includes an incidence plane, a reflection plane, an annular groove including a first annular face and a second annular face, and a light-outgoing plane. The annular groove is disposed so as not to cross with an optical path of light exited from the center of the light emitting element, entering the incidence plane and reflected by the reflection plane, and to cross with an at least a part of an optical path of the light exited from a point other than the center of the light emitting element, entering the incidence plane, reflected by the reflection plane and reaching the light-outgoing plane. The second annular face is formed in such a way that the width of the annular groove expands from a trough part of the annular groove towards an opening edge of the annular groove, and refracts the light exited from the light emitting element, entering the incidence plane and reflected by the reflection plane, towards the front side. |
