ILLUMINATION LENS, LIGHT EMITTING DEVICE, SURFACE LIGHT SOURCE, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an illumination lens capable of further widening directivity of a light source.SOLUTION: An outgoing face 12 of an illumination lens 1 has a first outgoing face 121 which is depressed toward a point on an optical axis A and a second outgoing face 122 which widens to the outside from a periphery part of the first outgoing face 121. The first outgoing face 121 includes a transmission region which transmits emission light of which angle from the optical axis A is less than a prescribed angle out of the emission light emitted from a base point Q being the position of the light source on the optical axis, and a total reflection region which totally reflects the emission light of which angle from the optical axis A is the prescribed angle or more out of the emission light emitted from the base point Q. A reflecting layer 10 which reflects the light reaching a bottom face 13 out of the light from the light source by repeating total reflection at the outgoing face 12 is formed on the bottom face 13 facing the opposite side to the outgoing face 12 at the surrounding of the incident face 11.