Illumination devices and methods of fabrication thereof

An illumination apparatus comprising:

• means for providing light;
• means for guiding light, wherein the light guiding means has a planar first surface, a first end and a second end, and a length therebetween, wherein the light guiding means is configured such that light from the light providing means provided into the light guiding means first end propagates generally towards the light guiding means second end;
• and
• a plurality of means for turning light, each means for turning light having a turning surface configured to receive light propagating towards the second end of the light guiding means and reflect at least a portion of the received light out of the light guiding means first surface, each means for turning light comprising an interferometric stack formed on the turning surface.

An illumination apparatus comprising:

• a light source;
• a light guide having a generally planar first surface, a first end and a second end, and a length therebetween, the light guide positioned to receive light from the light source into the light guide first end, and the light guide configured such that light from the light source provided into the first end of the light guide propagates generally towards the second end;
• and
• a plurality of light turning features, each light turning feature having a turning surface configured to receive at least a portion of the light which is propagating generally towards the second end of the light guide and reflect at least a portion of the received light out of the planar first surface of the light guide, each light turning feature comprising a reflective layer disposed over at least a portion of each turning surface;
• and
• a plurality of optical masks, each optical mask formed on a reflective layer.

A method of manufacturing an illumination apparatus, the comprising:

• providing a light guide;
• forming a turning film on the light guide;
• forming a plurality of light turning features on the turning film, each light turning feature comprising a light turning surface;
• and
• forming an interferometric stack on each light turning surface.