Patent ID: 7793840

Claim:
A variable focus imaging lens assembly for an imaging system of an imaging-based bar code reader for imaging a target object within a field of view of the imaging system, the imaging system generating image frames of the field of view and including an imaging sensor array, the variable focus imaging lens assembly defining an optical axis and comprising: a zoom lens assembly projecting light from the field of view onto the sensor array; the zoom lens assembly including a stationary lens group comprising a plurality of stationary lenses stationary with respect to the sensor array and a movable lens group comprising a plurality of movable lenses movable with respect to the sensor array in the imaging-based bar code reader, the movable lens group movable together along a path of travel parallel to the optic axis, at least one lens of the plurality of stationary lenses being intermediate a pair of lenses of the plurality of movable lenses; as the movable lens group moves in a first direction along the path of travel, a focal length of the imaging lens assembly increasing and an angle of the field of view decreasing and, as the movable lens group moves in a second direction, opposite the first direction, along the path of travel, the focal length of the imaging lens assembly decreasing and the angle of the field of view increasing, an image plane of the imaging lens assembly remaining substantially aligned with the sensor array during movement of the movable lens group; and a drive mechanism comprising a single drive motor to drive the movable lens group along the path of travel.