摘要 |
<p>An optical illumination system (2) comprising a waveguide (16) that accepts light generated by a diffuse light source (14) and transmits the light via total internal reflection. Attached on one surface of the waveguide (16) is a low index of refraction layer (27) and an array of microprisms (28), with each microprism (28) having a light input surface (30) and at least one sidewall tilted at an angle from the direction normal to the surface of the waveguide (16) such that light escapes from the waveguide (16), reflects off the tilted sidewalls (33) and emerges from the microprism (28) as a spartially-directed light source. The low index of reflection layer (27) prevents low angle light from entering the microprisms (28). An array of microlenses may be positioned to accept the output of the microprisms (28) so that the light existing from the microlenses is a substantially collimated light source. The optical illumination system (2) is advantageous for any application that requires a non diffuse or substantially collimated that is both energy efficient and contained in a low profile assembly.</p> |