Backlight module capable of enhancing brightness

A backlight module capable of enhancing brightness, comprising:

• a substrate, having a top surface;
• a circuit layout and a reflective layer being provided on the substrate;
• the reflective layer being located on the top surface;
• a plurality of LED light-emitting elements, being arranged in an array on the top surface of the substrate and electrically coupled to the circuit layout;
• each of the LED light-emitting elements having a light-emitting area that can emit light;
• the light-emitting area being defined with a light-emitting axis which extends vertically upward from a center point of the light-emitting area;
• a plurality of secondary optical lenses, each of said secondary optical lenses being fixed on the top surface of the substrate at a position corresponding to one of the LED light-emitting elements and covering the light-emitting area of the corresponding LED light-emitting element;
• and
• a diffuser plate, locating above the substrate and comprising:
• a plate body, having an upper surface and a lower surface, the lower surface facing the substrate;
• the plate body being a multi-layer structure formed by co-extrusion, comprising a main layer, an upper surface layer, and a lower surface layer;
• the upper surface layer is stacked on a side of the main layer facing the upper surface, and the lower surface layer is stacked on another side of the main layer facing the lower surface;
• a plurality of first diffusion particles, added to the main layer;
• a plurality of second diffusion particles, added to the upper surface layer and the lower surface layer;
• a plurality of microbubbles, being formed in the main layer by a foaming co-extrusion process;
• and
• a plurality of microstructures, being arranged in an array on at least the lower surface of the plate body;
• wherein, each of the secondary optical lenses is capable of diffusing the light emitted from the light-emitting area of the corresponding light-emitting element in a manner of refraction, reflection, or both refraction and reflection;
• in addition, among the light emitted upward from the light-emitting area of the light-emitting element, a light intensity within an angle range of +30° to −30° with the light-emitting axis is between 15% and 25% of the total light intensity of the light-emitting element, and the light intensity within the angle range of +60° to +70° and −60° to −70° with the light-emitting axis is between 75% and 85% of the total light intensity of the light-emitting element.