Patent Number: 7,821,727

Title: Lens driving device

Abstract: A lens driving device, comprises a base; a casing fixed to the base; a coil bracket disposed within the casing; a coil wound on the coil bracket, a spring disposed within the casing, a drive rod; and a lens holder; wherein, one end of the spring is fixed to the base; one end of the drive rod is fixed to the other end of the spring, and the other end of the drive rod extends out of the casing. The lens holder is slidably fixed to the exposed portion of the drive rod. The lens holder is held stationary with respect to the drive rod by static friction between the drive rod and the lens holder. A driving signal may be applied to the coil to move the lens holder. The driving signal has the characteristic of making the current flowing through the coil slowly increase and then rapidly decrease, or to rapidly increase and then slowly decrease. The drive current is preferably a sawtooth pulse train, with each pulse causing movement of the lens holder in the micron range or below.

Inventors: Shi; Bin (Hong Kong, CN), Li; Hong (Shenzhen, CN), Li; Xingquan (Shenzhen, CN)

Assignee: Johnson Electric S.A.

International Classification: G02B 7/02 (20060101); G02B 15/14 (20060101)

Expiration Date: 2018-10-26 0:00:00