An optical device for collecting light and selectively outputting or
concentrating the light. A layer has an optical index of referaction
n.sub.1, and top, bottom and side surfaces defining an angel of
inclination .phi.. A back surface spans the top, bottom and side surface.
A first layer is coupled to the bottom surface of the layer and has an
index of refraction n.sub.2. The first layer index n.sub.2 causes light
input through the back surface of the layer to be preferentially output
into the first layer. A second layer is coupled to the bottom of the
first layer and selectively causes output of light into ambient.
Additional layers, such as alight polarization layer, a polarization
converting layer and a post LCD diffuser layer can be used to make
preferential use of polarized light of diffuse light having passed
through the LCD layer to enhance viewing of the output light.