Light bundle control member, light emitting device, area light source device, and display device

A light flux controlling member configured to control a distribution of light emitted from a light-emitting element, the light flux controlling member comprising:

• an incidence surface that is an inner surface of a recess that is open toward a rear side of the light flux controlling member so as to intersect a central axis of the light flux controlling member, the incidence surface being configured to allow incidence of the light emitted from the light-emitting element;
• an emission surface disposed on a front side of the light flux controlling member so as to intersect the central axis, the emission surface being configured to emit, to outside, light entered from the incidence surface;
• a rear surface connected with an opening edge of the recess, the rear surface being formed so as to extend away from the opening edge of the recess;
• a protrusion disposed on the rear surface so as to protrude toward the rear side from the rear surface;
• and
• a leg part protruding toward the rear side from the rear surface;
• wherein the leg part being configured to mount the light flux controlling member to a substrate where the light-emitting element is disposed;
• wherein the leg part includes a contact surface configured to make contact with the substrate;
• wherein the contact surface of the leg part is closer to the rear side than an end surface of the protrusion;
• and
• wherein the end surface of the protrusion and at least a region surrounding the protrusion in the rear surface have different properties.