US Patent 9857556 Apparatus for auto focus

Disclosed is an apparatus for auto focus, which includes a first frame having a magnet, a second frame having an auto focus (AF) coil for moving the first frame in an optical axis direction and a yoke giving an attractive force to the magnet, and a plurality of balls arranged in the optical axis direction and located between the first frame and the second frame so that the first frame and the second frame are maintained to be spaced apart from each other. An entire height of the plurality of balls is equal to or higher than a height of the magnet on the basis of the optical axis direction.