CUSTOMIZED DEPTH OF FIELD OPTICAL SYSTEM AND COMPACT FAST LENS ARCHITECTURE

摘要

A fixed optical unit (200) includes one or more fixed optical elements (202). The optical unit has a modulation transfer function (MTF), for a given object distance and a given spatial frequency associated with an imaging surface of an image sensor disposed at a selected distance from the fixed optical unit, which varies with object distance such that the MTF is at a maximum at a selected image distance, decreases from about the maximum MTF to below a predefined threshold value within a first range of positive focus shifts corresponding to image distances less than the selected object distance, and decreases from about the maximum MTF but remains above the predefined threshold value over a second range of negative focus shifts corresponding to image distances greater than the selected object distance. The second range of negative focus shifts is larger than the first range of positive focus shifts.