Importance

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Abstract

An optical scanning module has a metal base, a first circuit board mounted across one end of the metal base and a second circuit board mounted orthogonal to the first circuit board. The metal base supports a light emitter for producing a scanning beam and serves as a heat sink for the emitter. A flexible support attached to the metal base supports a mirror for oscillating motion. The module includes a drive mechanism, typically in the form of a permanent magnet and electromagnet, for producing reciprocal motion of the mirror. A detector included in the module senses light reflected from an indicia scanned by the beam. A flexible electrical cable connects the circuitry on the first and second circuit boards so that circuitry operates together to produce all signals necessary for operation of the scanner module and to process the electrical signals from the detector. Preferred embodiments include a flexible support consisting of a planar spring located between the mirror and one of the magnets. The components of the module are dimensioned so that the weight of the magnet balances that of the mirror. The invention also encompasses systems for scanning the beam simultaneously in two orthogonal directions at two different frequencies. This bi-directional scanning can produce a raster scan pattern for reading two-dimensional bar codes, or this scanning can produce a moving zig-zag pattern for reading truncated bar codes.

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First Claim