Abstract: A backlight module including an LGP, an optical film, a first light source is provided. The LGP has a bottom surface, a light emitting surface, a first light incident surface, and microstructures. Each microstructure is recessed into or protrudes out of the bottom surface and includes at least two structural units. A section line of each structural unit on a first reference plane is a curve, and the curve has a peak point. A distance between two peak points of two adjacent structural units along a first direction is greater than 0 and smaller than a half of a total width of the two structural units along the first direction. Each microstructure has a symmetric plane perpendicular to the light emitting surface and the first light incident surface. The optical film is located on the light emitting surface. The first light source is located beside the first light incident surface.

Abstract: A backlight module including an LGP, an optical film, a first light source is provided. The LGP has a bottom surface, a light emitting surface, a first light incident surface, and microstructures. Each microstructure is recessed into or protrudes out of the bottom surface and includes at least two structural units. A section line of each structural unit on a first reference plane is a curve, and the curve has a peak point. A distance between two peak points of two adjacent structural units along a first direction is greater than 0 and smaller than a half of a total width of the two structural units along the first direction. Each microstructure has a symmetric plane perpendicular to the light emitting surface and the first light incident surface. The optical film is located on the light emitting surface. The first light source is located beside the first light incident surface.