2X optical digital zoom lens with short total length and extremely small front aperture for two-million-pixel CMOS on mobile phones

Abstract

2X Optical Zoom lenses on compact mobile phone are nowadays increasingly demanded but few samples with 2X optical zoom function have succeeded in being compactable with very thin mobile phones, especially when more than two million pixels CCD or CMOS are involved. Most mobile phone designers are reluctant to increase the thickness of mobile phones to accommodate the 2X optical zoom lens or to redesign the whole mobile phone to fit a lens with a large front diameter into the right place. In this paper, a newly designed 2X Zoom lens with an extremely small front diameter is proposed for mobile phones offering two million pixels because the aperture stop is at the first element of this 2X optical zoom lens. Additionally, its total overall length is reduced to something reasonably small compared with that of current mobile phone systems with two million CMOS pixels. The result is that its MTF (modulation transfer function) and other aspects of performance meet the requirements of an optical zoom lens with two million pixels CMOS.