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 disposed on a rear side of the light flux controlling member, the recess being disposed 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 to intersect the central axis, the emission surface being configured to emit, to outside, light entered from the incidence surface;
• a plurality of grooves sequentially disposed in a direction toward an outer edge side of the light flux controlling member from a central axis side on the rear side of the light flux controlling member, each of the plurality of grooves including a step surface located on the central axis side and an inclined surface located on the outer edge side;
• and
• a plurality of ridges disposed in the inclined surface of each of the plurality of grooves, each of the plurality of ridges including a first reflection surface, a second reflection surface, and a ridgeline disposed between the first reflection surface and the second reflection surface,
• wherein at least one of the incidence surface and the emission surface has a shape of an ellipse in a cross-section perpendicular to the central axis,
• wherein when the incidence surface has the shape of the ellipse in the cross-section, at least one of the plurality of ridges is disposed in the inclined surface located outside the recess in a direction of a minor axis of the ellipse, and
• wherein when the emission surface has the shape of the ellipse in the cross-section, at least one of the plurality of ridges is disposed in the inclined surface located outside the recess in a direction of a longitudinal axis of the ellipse.