Abstract: A thin plastic light guide is formed to have cavities on one surface and TIR (total internal reflection) structures directly above the cavities. LEDs mounted on a printed circuit board are positioned in the cavities. The cavity walls are shaped to refract the LED light and direct the LED light toward the TIR structures to most efficiently make use of the TIR structures. The TIR structures may have a cusp or cone shape. The top ceiling of the cavities may be shaped to direct light at the TIR structure so as to leak through the TIR structure and blend the light with light leaking through surrounding portions of the light guide. The LEDs may be distributed only near the edges of the light guide or over the entire back surface of the light guide. A diffuser sheet may be laminated over the light guide to further mix the light.

Abstract: A backlight uses an array of red, green, and blue LEDs in a mixing chamber. The mixing chamber has reflecting surfaces and a top opening for illuminating LCD layers. A desired brightness profile and better color uniformity are obtained by using techniques including arranging the LEDs in certain sequences and patterns, providing a specular ring at the base of each LED, attenuating the brightness of the LEDs at the edges, and using widely separated diffusers in the mixing chamber. The arrangement, selection, and control of the multicolored LEDs may be tailored to achieve any desired white point specified by the display manufacturer.

Abstract: A mixing chamber includes a first surface and a second surface opposite the first surface. At least two light emitting diodes are disposed along the first surface. At least a portion of the first surface is reflective, and the second surface includes a reflective region and a plurality of openings formed in the reflective region. In some embodiments, the first surface and the second surface are separated by at least one side surface. Light emitted from the light emitting diodes is reflected off the first surface, reflective region of the second surface, and side surfaces of the mixing chamber until it is emitted from the openings of the second surface.

Abstract: A backlight uses an array of red, green, and blue LEDs in a mixing chamber. The mixing chamber has reflecting surfaces and a top opening for illuminating LCD layers. A desired brightness profile and better color uniformity are obtained by using techniques including arranging the LEDs in certain sequences and patterns, providing a specular ring at the base of each LED, attenuating the brightness of the LEDs at the edges, and using widely separated diffusers in the mixing chamber. The arrangement, selection, and control of the multicolored LEDs may be tailored to achieve any desired white point specified by the display manufacturer.

Abstract: A mixing chamber includes a first surface and a second surface opposite the first surface. At least two light emitting diodes are disposed along the first surface. At least a portion of the first surface is reflective, and the second surface includes a reflective region and a plurality of openings formed in the reflective region. In some embodiments, the first surface and the second surface are separated by at least one side surface. Light emitted from the light emitting diodes is reflected off the first surface, reflective region of the second surface, and side surfaces of the mixing chamber until it is emitted from the openings of the second surface. In another embodiment, a structure includes a light emitting diode, a lens overlying the light emitting diode, and a diverting optic overlying the lens. The diverting optic may include, for example, a specular or diffuse reflector, a bulk or film diffuser, and a transparent material.