LCD backlight assembly

The utility model discloses an LCD backlight assembly comprising light sources and a light tunnel. The light tunnel comprises a light incoming surface, a light outgoing surface and a reflection chamber. The light incoming surface is polygon-shaped. The light outgoing surface is also polygon-shaped, the number of edges of the light outgoing surface is equal to that of the light incoming surface, and the light outgoing surface is parallel to the light incoming surface. The reflection chamber connects the light incoming surface and the light outgoing surface, is provided with inner walls totally inflecting light, and is polygonal and tapered. The side surfaces of the reflection chamber are multiple trapezoids on different planes, shorter upper bases of the multiple trapezoids form the periphery of the light incoming surface, and longer lower bases form the periphery of the light outgoing surface. Common and low cost total reflection materials are employed in the LCD backlight assembly, and the light emitted by the light sources are totally reflected for many times, so that the intensity and uniformity of emergent light illuminance are improved, light outgoing angles are optimized, and backlight sources having optimized illumination and light distribution angles can be provided for an LCD panel without a complex and high cost optical system.