Patent ID: 8810749
Filing Date: 2014-08-19
Classification: G02B,G02F,Y10T

Abstract:
1. A method for making a backlight source with reduced thickness, comprising: placing a light emitting diode (LED) array including a plurality of LED chips below a light transmitting unit; wherein the light emitted by the LED chips are transmitted through the light transmitting unit as an output light of the backlight source; placing a plurality of light adjusting units between the LED array and the light transmitting unit, above the plurality of LED chips, wherein each light adjusting unit includes an edge-emitting filter plate or film which reflects incident lights having incident angles smaller than a threshold angle and transmits incident lights having incident angles larger than or equal to the threshold angle, wherein each light adjusting unit spatially corresponds to one LED chip; and providing, between each of the edge-emitting filter plates or films and the corresponding LED chip, an air gap having a thickness defined as a distance between the edge-emitting filter plate or film and a light emitting surface of the LED chip less than ⅕ of a bounding circle diameter of a light emitting area of the LED chip, and wherein each light adjusting unit reflects small-angle emitted light from the LED chip back to the LED chip, wherein the LED chip reflects or scatters the light reflected from the light adjusting unit back to the light adjusting unit at various angles, whereby a spatial distribution of light intensity of the light from the LED chips to the light transmitting unit is adjusted by the light adjusting units.