A system for enhancing the quality of an image on a screen is provided. The system typically includes an illumination source configured to produce light and direct such light along an optical path, and a time-varying focus device disposed in the optical path and configured to periodically alter incident...http://www.google.fr/patents/US6729734?utm_source=gb-gplus-shareBrevet US6729734 - System for enhancing the quality of an image
