BEAM EXPANDER USING TWO POWER-ADJUSTABLE LENSES

摘要

A variable beam-expander including a first lens (210) having a first focal length (fl) that is adjustable by a control circuit (230) and a second lens (220) having a second focal length (f2) that is adjustable by the control circuit (230), wherein the control circuit (230) adjusts the first (f1) and second focal lengths (f2) such that the sum of the first and second focal lengths (f1 + f2) is equal to the fixed distance (L) separating the first lens (210) and the second lens (220).