BLACKWOOD, N.J., Oct. 6 -- Metrologic Instruments Inc. reports that it has received a US patent for its HoloTrak holographic bar code scanners. Metrologic's holographic technology incorporates the Holodisc, which contains up to 24 holographic elements that focus a laser beam, move it across the bar code, and receive the light reflected back from the bar code. The holographic scanners use the turning Holodisc to focus several laser beams into multiple focal planes, creating thousands of scan lines per second to form a large, dense scan field. Metrologic's HoloTrak bar code scanners are used worldwide for hands-free, work-in-process, walk-under, and high-speed conveyor scanning applications.