Patent ID: 8721153

Claim:
A turning film backlight, comprising: a lightguide, a light guiding region of the lightguide having an exit surface, a back surface, and at least one input edge, the light guiding region having a substantially spatially uniform refractive index; at least one light source arranged to supply light to the input edge of the lightguide; a turning film arranged to direct light emerging from the lightguide exit surface toward an illumination field and comprising a plurality of prisms having prism peaks facing the exit surface of the lightguide; a reflector disposed along the back surface of the lightguide, the reflector comprising: a reflective layer; and a prism layer in contact with the reflective layer and disposed between the reflective layer and the back surface of the lightguide, the prism layer comprising a series of substantially linear prisms having prism peaks facing the back surface of the lightguide.