Optical camera with liquid crystal autofocus lens.

Abstract

A mobile phone camera with an innovative electrically tunable liquid crystal lens (TLCL) concept is demonstrated. We first report the comparative theoretical and experimental analyses of the performance of a traditional "modal control" TLCL versus a TLCL using a floating (unpowered) transparent electrode (FTE). It is shown that the appropriate choice of voltage and frequency values of the driving electric signal may improve significantly (almost twice) the optical quality of the lens using the FTE. Exceptionally low spherical aberrations of the lens (< λ/10 for up to 10 diopters of optical power) and high modulation transfer functions of a mobile phone camera (using those lenses for autofocus function) are demonstrated in a very simple operation mode (frequency tuning of the lens' optical power at a fixed driving voltage). The capacity of the camera to perform high quality long distance photography and near distance bar code recognition within a short autofocus convergence time are demonstrated.