Backlight systems for liquid crystal displays

A backlight system for a liquid crystal display, comprising:

• a substantially planar, refractive waveguide including a first major face and a second major face opposite the first major face, the waveguide including a viewable region corresponding to a viewable area of the liquid crystal display;
• a plurality of light sources positioned proximate to the second major face and within the viewing region for producing light;
• a plurality of injection features proximate to one or more of the second major face and the first major face and within the viewing region to optically couple the light into the waveguide such that the light becomes waveguided light;
• and
• a plurality of extraction features proximate to one or more of the second major face and the first major face and within the viewing region to optically couple the waveguided light out of the waveguide,
• wherein the plurality of extraction features includes extraction features arranged in a first group and a second group adjacent to the first group, and wherein the waveguide includes a first area corresponding to the first group of extraction features and a second area corresponding to the second group of extraction features, and
• wherein the first group of extraction features defines a localized spread function such that light in the first area spreads substantially evenly through the first area without substantially spreading into the second area.

A backlight system for a liquid crystal display, comprising:

• a substantially planar, refractive waveguide including a first major face and a second major face opposite the first major face, the waveguide including a viewable region corresponding to a viewable area of the liquid crystal display;
• a plurality of light sources positioned proximate to the second major face and within the viewing region for producing light, the plurality of light sources including first light sources having a first color and second light sources having a second color, different from the first color;
• a plurality of injection features proximate to one or more of the second major face and the first major face and within the viewing region to optically couple the light into the waveguide such that the light becomes waveguided light, the plurality of injection features including first injection features configured to inject light from the first light sources and second injection features configured to inject light from the second light sources;
• and
• a plurality of extraction features proximate to one or more of the second major face and the first major face and within the viewing region to optically couple the waveguided light out of the waveguide.