Backlight module with light-guiding portions

A backlight module comprising:

• a substrate;
• a plurality of separate light emitting diode (LED) packages mounted on the substrate;
• and
• a light diffusion board located above the LED packages, the light diffusion board comprising a light incident surface oriented toward the LED packages and a light outputting surface opposite to the light incident surface, a plurality of light-guiding portions being configured extending from the incident surface of the light diffusion board, the light-guiding portions facing toward and aligned with the LED packages, respectively, each light-guiding portion comprising a concave surface, light emitting into the light-guiding portions being divergently refracted by the concave surfaces of the light-guiding portions into the light diffusion board;
• wherein the concave surface is recessed inwardly from an outer periphery of the light-guiding portion;
• wherein a curvature of the concave surface is varied from 0.5 mm-1 to 1.5 mm-1;
• wherein each light-guiding portion is funnel shaped, and a diameter of the light-guiding portion is decreasing gradually from a top end connecting the light diffusion board to a bottom end facing toward a corresponding LED package;
• and
• wherein the backlight module further comprising covers covering the LED packages respectively, each cover defines a cavity therein, and the cavity receives a corresponding LED therein.