Patent ID: 8629932
Filing Date: 2014-01-14
Classification: H04N

Abstract:
1. A camera module, comprising: a tunable liquid crystal lens including a dual-frequency liquid crystal layer configured to vary an optical power thereof in response to a drive signal applying an electrical field across said liquid crystal layer, said dual-frequency liquid crystal layer having liquid crystal molecules with a major axis thereof being attracted to align parallel to said electrical field and repulsed from said electric field as a function of drive signal frequency; a drive circuit for generating the drive signal so that the tunable lens performs a focus scan of the optical power; an image sensor configured to acquire light images passing through the tunable lens and to convert the light images to image signals during the focus scan; a processor for generating focus scores of the acquired light images using the image signals during the focus scan, the processor being configured to determine from the focus scores a peak focus score achieved or achievable, and to instruct the drive circuit to adjust the drive signal so that the tunable lens substantially settles at a value of the optical power that corresponds to the peak focus score; wherein the processor is configured to instruct the drive circuit to cause said axis of said liquid crystal molecules to be attracted to and to be repulsed from said electric field during said focus scan and subsequently to settle at the optical power value corresponding to the peak focus score.