THIN BACKLIGHT USING LOW PROFILE SIDE EMITTING LED

摘要

Low profile, side-emitting LEDs are described. The LEDs are used in very thin backlights for backlighting an LCD. In one embodiment, the backlight comprises a solid transparent waveguide (66) with at least one opening in the waveguide containing an LED (10) proximate to one edge. To smooth out a clover-shaped or batwing brightness profile inherently generated by a rectangular side-emitting LED within a smooth-sided rectangular opening in the waveguide, depending on the orientation of the LED, the sidewalls (68) of the opening are made to have varying angles along the length of each sidewall to vary the refraction angle of light along the sidewall. Additionally, if a plurality of LEDs are used in the backlight, the orientations of the openings alternate to create a more uniform brightness profile (64) in the waveguide (62).