Patent ID: 7142368

Claim:
An auto-focusing optical system comprising, sequentially from an object side: a first lens group having a plus optical power, the first lens group including a liquid lens in which a curvature of a boundary surface formed between different liquids included in an inside is varied depending on an applied voltage so that the boundary surface performs a function of a lens' surface, and an aspherical lens having an aspherical surface formed on at least one refractive surface thereof; a second lens group having a plus optical power, and including an aspherical lens having an aspherical surface formed on at least one refractive surface thereof; a third lens group a minus optical power, and including an aspherical lens having an aspherical surface formed on at least one refractive surface thereof; and wherein the curvature of the boundary surface of the liquid lens is varied so that an auto-focusing is performed.