Stacked backlighting system using microprisms

A method for providing a backlighting assembly having a particular viewing axis, comprising the steps of:

• providing a plurality of light pipes, each including top and bottom surfaces which define a light pipe interior, each of said plurality of light pipes being configured to be illuminated by at least one linear light source at a light entering end, each of said plurality of light pipe further being configured to direct light from said at least one linear light source into a respective light pipe interior in a predetermined way;
• stacking said plurality of light pipes so that together they are configured to provide multi-level modes of one-dimensional collimated illumination output light beams having at least one characteristic propagation direction;
• and
• passing the output light beams through a prismatic film substantially symmetric about the particular viewing axis and bending the beams toward the viewing axis.

A backlighting assembly comprising:

• first and second light pipes, each including top and bottom surfaces which define a light pipe interior;
• illumination means coupled to a first light entering end of the first light pipe and an opposed second light entering end of the light pipe;
• illumination means coupled to a light entering end of the second light pipe, wherein said plurality of light pipes are together assembled so that they are configured to provide multi-level modes of one-dimensional collimated illumination;
• and
• a prismatic film substantially symmetric about the particular viewing axis adapted to intercept the multi-level modes of one-dimensional collimated illumination and bend the illumination toward the viewing axis.