Illumination apparatus

An illumination apparatus, comprising:

• a frame;
• an optical base plate disposed in the frame and having a protrusion area at the center thereof, wherein the protrusion area has at least a protrusion portion, the protrusion portion has at least a reflective surface, and the reflective surface comprises a plurality of inclined surfaces with different inclination angles;
• a light source disposed in the frame and located adjacent to the periphery of the optical base plate, wherein the light source is disposed corresponding to the reflective surface and has a plurality of light-emitting elements, each of the light-emitting elements has an optical axis direction, and the optical axis directions extend toward the protrusion area;
• and
• an optical film disposed at the frame, wherein the protrusion portion of the optical base plate protrudes toward the optical film;
• wherein the light source further comprises a substrate, and the light-emitting elements are disposed on the substrate,
• wherein a part of the light-emitting elements disposed close to the center of the substrate has higher distribution density than a part of the light-emitting elements disposed away from the center of the substrate.