US Patent 7134776 Direct backlight and display device

A direct backlight includes a plastic spacer pin. The spacer pin is formed of a semispherical portion and a conical frustum portion. The spacer pin is disposed such that the thicker end of the conical frustum portion is coupled to the bottom surface of the chassis, with the semispherical portion placed to face a diffuser plate. The radius of curvature of the tip of the semispherical portion is 0.3 mm to 1 mm. The diameter of the end of the conical frustum portion on the semispherical portion side is 1.1 mm to 2 mm. The ratio (L/B) is less than 5 where L is the length of the spacer pin and B is the diameter of the thicker end of the conical frustum portion.