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Automatic bar code reading system having selectable long range and short range modes of operation

DC
  • US 5,340,971 A
  • Filed: 09/17/1991
  • Issued: 08/23/1994
  • Est. Priority Date: 09/17/1990
  • Status: Expired due to Term
First Claim
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1. A scanning system for scanning a coded symbol located on an object, said system comprising:

  • a hand-holdable housing having a transmission aperture permitting passage of light out of and into said housing;

    object detection means within said housing for detecting object sensing energy within an object detection field defined external to said housing, and for automatically producing a first signal indicative of the presence of an object within said object detection field, said object detection means having at least a short-range and a long-range mode of object detection, wherein, when said object detection means is in said short-range made of object detection, said object detection means is capable of detecting the presence of an object located within a short range measured from said transmission aperture out towards a first region within said object detection field, andwherein, when said object detection means is in said long-range mode of object detection, said object detection means is capable of detecting the presence of an object located within a long-range measured from said transmission aperture out towards a second region within said object detection field;

    scanning means disposed within said housing for producing in automatic response to said first signal, a light beam and scanning said light beam through said transmission aperture and across a scan field defined external to said housing, said scanning system having an operative scanning range measured from said transmission aperture out towards a region within said scan field, said scan field being characterized as having at least one scanning plane of essentially planar extent and said object detection field being characterized as having an essentially volumetric extent, and said object detection field spatially encompassing at least a portion of said scan field within said operative scanning range of said scanning means;

    light detection means disposed within said housing for detecting at least a portion of light of variable intensity reflected off said object in said scan field and passing through said transmission aperture, and for producing scan data representative of the detected light intensity;

    first processing means for processing scan data and producing a second signal indicative of the presence of a coded symbol on said object within said scan field;

    second processing means responsive to said second signal, for processing scan data from said light detection means so as to produce symbol character data representative of a decoded symbol and providing an output signal indicative of said decoded symbol; and

    means on said housing for manually producing a short-range mode activation signal.

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