Planar light apparatus

A planar light apparatus, comprising:

• a reflection part having a reflecting surface;
• a secondary optic device having a light incident surface, a light emitting surface, and a side surface between the light incident surface and the light emitting surface, a void space being formed between the secondary optic device and the reflection part, the reflecting surface facing the void space, the secondary optic device being disposed such that the light emitting surface faces the void space, the side surface being an elliptic surface, a focus of the elliptic surface being located in the void space, a projection of the focus on the reflecting surface being at a center of the reflecting surface;
• and
• a light-emitting device disposed opposite to the light incident surface, wherein light beams emitted by the light-emitting device into the secondary optic device through the light incident surface are capable of being reflected by the side surface to emit out of the secondary optic device through the light emitting surface into the void space to be reflected by the reflecting surface.