An automatic fast focusing infinitely variable focal power Lens Unit, to supply the infinitely variable focal power as required. The Lens Unit consists of two lenses, one of which is stationary, being connected to an eyeglass frame or other optical products with the outer lens moving in connection with...http://www.google.com.au/patents/US5229885?utm_source=gb-gplus-sharePatent US5229885 - Infinitely variable focal power lens units precisely matched to varying distances by radar and electronics
