Patent ID: 7480004
Filing Date: 2009-01-20
Classification: G02B,G03B,H04N

Abstract:
1. A two-step auto focus lens system for a digital camera, comprising: a coil base, having two ends and a coil, the coil being around the coil base and between the two ends; a sensor, disposed corresponding to one end of the coil base; and the electrical current on the coil driving the coil base to switch magnetic polarities of the two ends of the coil base; and a lens barrel, movably installed inside the coil base and having a magnetic component corresponding to the other end of the coil base, wherein the lens barrel has an arm in contact with the inner surface of the coil base to produce friction between the arm and the coil base; wherein the lens barrel is alternately moved between a near focal point and a far focal point, by magnetic repulsion and magnetic attraction respectively between the magnetic component and the coil base when the coil base is driven by the sensor to switch the magnetic polarities of the two ends of the coil base and the lens barrel is positioned at the near focal point or the far focal point by the friction.