A liquid crystal light modulation device conprises a pair of substrates at least one of which is transparent, a diffraction grating formed between or on at least one of the substrates, a liquid crystal arranged between fine grooves of the diffraction grating, and control means for changing the orientation...http://www.google.de/patents/US4729640?utm_source=gb-gplus-sharePatent US4729640 - Liquid crystal light modulation device
