Bar Code Laser Scanner

Citation

Rigelsford, J. (2003), "Bar Code Laser Scanner", Sensor Review, Vol. 23 No. 3. https://doi.org/10.1108/sr.2003.08723cad.014

Bar Code Laser Scanner

Bar Code Laser Scanner

Applicant: Symbol Technologies, Inc., USAPatent number: US6,348,773Publication date: 19 February 2002Title: Laser scanner for controlling the optical scanning of bar codes

Keywords: Laser scanning, Bar codes, Patents

This invention relates to the design of scanning systems for automatically reading both one-dimensional and two-dimensional bar code symbols.

The invention provides a system for examining the optical reflections to determine whether a sensed target is a bar code symbol and, if so, whether that symbol is a one-dimensional or two-dimensional code. If the symbol is a two-dimensional code, the present invention aligns the two-dimensional scanning pattern with the symbol and expands the pattern to the top and bottom edges of the symbol.

Additionally, a microprocessor-controlled scan engine is provided that uses a coil both to drive a scanning element and to pick up feedback signals representing the motion of the scanning element. A pulse-width- modulated regulator also provides fast and efficient operation for driving the coil. The scan engine also uses different circuit techniques to avoid degrading the system, and has a powerful interface to decoding and control logic of the scanner. The scan engine may be set to ensure that gaps in the two- dimensional scanning patterns do not occur. This is achieved by moving the scan lines to different portions of the bar code symbols.