Patent ID: 9169991
Filing Date: 2015-10-27
Classification: F21Y,G02B

Abstract:
1. A lens for use in a direct-type backlight module to spread light from a light source to a light diffusion board, comprising: a light incident surface located at a lower portion of the lens; and a light output surface located at an upper portion of the lens and opposite to the light incident surface, a depression aligned with the light source being defined in a central portion of the light output surface, a plurality of light diverging portions being arranged in the depression, the light diverging portions being protruded upwardly from a central portion of the light output surface and around the a central axis of the lens, refraction angles of the light diverging portions decreasing along a direction from the central axis of the lens toward a periphery of the lens, light travelling through the lens from the light incident surface being refracted by the light output surface and the light diverging portions to uniformly emit out; wherein each light diverging portion comprises a vertical surface extending upwardly from the light output surface and a light diverging surface inclined from a top end of the vertical surface towards the light output surface; wherein the light diverging surface of each light diverging portion is inclined downwardly and outwardly from the top end of the vertical surface toward the light output surface of the lens and along the direction from the central axis of the lens toward the periphery of the lens; and wherein an inclined angle is defined between the vertical surface and the light diverging surface of each light diverging portion, and the inclined angle of the light diverging portion near the center of the depression is larger than the inclined angle of another light diverging portion away from the center of the depression.