Method of and system for scanning bar code symbols using a laser scanning pattern having multiple focal zones, wherein the minimum beam dimension/minimum bar width (mbd/mbw) ratio is greater than or equal to 2.0

A multi-focal zone laser scanning system for scanning bar code symbols having a minimum bar element width (MBW), said multi-focal zone laser scanning system comprising:

• a laser beam producing device for producing a laser beam;
• a laser beam scanning mechanism for scanning said laser beam so as to generate a laser scanning pattern having a plurality of different focal zones and producing an analog scan data signal representative of a bar code symbol scanned by said laser scanning pattern, and
• a scan data signal processor for processing said analog scan data signal, said scan data signal processor including
• a plurality of different pass-band filters, wherein one of said pass-band filters is dynamically switched into operation for pass-band filtering the analog scan data signal produced by said laser beam scanning a bar code symbol within one of said plurality of different focal zones so as to filter out spectral components of paper noise residing outside the frequency spectrum of said analog scan data signal produced in response to scanning said bar code symbol within said different focal zone;
• wherein said scanned laser beam has a minimum beam dimension (MBD) with each said focal zone, and
• wherein the ratio of said minimum beam dimension (MDB) within each said focal zone to said minimum bar element width (MBW) of a scanned bar code symbol within said focal zone (i.e. MDB/MBW) is greater than or equal to 2.0.