Bar code scanner with collimated scan volume

Abstract

An optical scanner comprising an automatic (i.e., triggerless) portable bar code symbol reading device with an omnidirectional scanning engine mounted within the head portion of its housing, and adapted for use with an associated base unit. The bar code symbol reading device produces a confined scanning volume for omnidirectional scanning of code symbols presented therein, while preventing unintentional scanning of code symbols on nearby objects located outside of the confined scanning volume.

What is claimed is:  
     
         1 . An optical scanner comprising: 
 (a) a housing having an optically admissive window through which optical energy of at least one wavelength can exit said housing, travel towards an object bearing a code symbol and reflect therefrom, at least a portion of the reflected optical energy travelling back through the optically admissive window to enter the housing; wherein the housing has a central reference axis extending approximately upwards and downwards in a longitudinal direction;    (b) an optical energy producing mechanism disposed within the housing for producing a beam of optical energy;    (c) a beam sweeping mechanism mounted within the housing with respect to the central reference axis for rotation about a rotational axis intersecting the central reference axis, where the intersection of the rotational axis and the central reference axis defines a central reference plane; the beam sweeping mechanism including a plurality of rotating light reflective surfaces each being disposed at a different acute angle with respect to the rotational axis, for sequentially sweeping the beam about the rotational axis along a plurality of different paths;    (d) a stationary array including a plurality of stationary optically reflective surfaces mounted within the housing with respect to the central reference axis and disposed substantially underneath said optically admissive window; wherein at least two of the plurality of said stationary optically reflective surfaces are substantially symmetrically disposed on opposite sides of the central reference plane, and closely adjacent to the beam sweeping mechanism;    (e) an optical energy collection subsystem disposed within the housing, and including    (1) an optical collection element, mounted along the central reference plane and adjacent at least two of the stationary optically reflective surfaces, for allowing the beam produced by the optical energy producing mechanism to pass along a portion of the central reference plane, to the beam sweeping mechanism, for sweeping about the rotational axis thereof along the plurality of different paths, and    (2) an optical receiver for receiving optical energy from the optical collection element at a point substantially within the central reference plane, detecting the received optical energy and producing an electrical signal indicative of said detected optical energy;    (f) a signal processor for processing the electrical signal and producing scan data representative of a scanned code symbol;    (g) a control mechanism for controlling the operation of the scanner so that, during scanner operation, the beam produced by the optical energy producing mechanism passes along a portion of the central reference plane, to at least one of the rotating optically reflective surfaces of the beam sweeping mechanism, and as the beam sequentially reflects off a plurality of the rotating light reflective surfaces, the beam is repeatedly swept across a plurality of the stationary light reflective surfaces, thereby producing a plurality of groups of plural scan lines, respectively, which are projected out through the optically admissive window and intersect about a projection axis within a collimated scanning volume having an approximately columnar extent and extending from adjacent the optically admissive window to at least about six inches therefrom so as to produce a collimated projected scanning pattern; and    (h) the housing being supportable relative to an object bearing a code symbol so that when a code symbol is presented within the collimated scanning volume,    (i) the code symbol is scanned omnidirectionally by the collimated scanning pattern,    (ii) at least a portion of the optical energy reflected from the scanned code symbol is directed through the optically admissive window, reflected off at least one of the stationary optically reflective surfaces, and then reflected off at least one of the rotating optically reflective surfaces of the beam sweeping mechanism, and    (iii) thereafter, the reflected optical energy is collected by the optical collection element, and received by the optical receiver for detection, whereupon the electrical signal is produced for processing by the signal processor;    wherein the housing permits a user to control the direction of the projection axis so as to align the collimated scanning volume with the bar code symbol on the object to be scanned.    
     
     
         2 . The scanner of    claim 1   , wherein the signal processor further comprises a data processor for decoding the scan data and producing data representative of the scanned code symbol.  
     
     
         3 . The scanner of    claim 1   , wherein said different acute angles are selected so that the scan lines in each said group of scan lines are substantially equidistant from each other throughout at least a range of distances from the optically admissive window.  
     
     
         4 . The scanner of    claim 1   , wherein the optical energy producing mechanism comprises a laser diode mounted with respect to the central reference axis.  
     
     
         5 . The scanner of    claim 1   , wherein said first, second, third, and fourth stationary light reflective surfaces comprise first, second, third, and fourth mirrors, respectively.  
     
     
         6 . The scanner of    claim 1   , wherein the housing includes a head portion and handle portion extending from the head portion, and the optically admissive window is disposed within the head portion.  
     
     
         7 . The scanner of    claim 1   , wherein the collimated scanning pattern is oriented along a longitudinal extent of the housing so as to facilitate scanning of code symbols presented to the collimated scanning volume.  
     
     
         8 . The scanner of    claim 1   , further comprising a scanner support stand positionable upon a counter surface, and including a supporting mechanism for supporting the housing in any one of a plurality of positions above a counter surface so that the collimated scanning pattern is projected about the projection axis above the counter surface in any one of a plurality of orientations corresponding to the plurality of positions.  
     
     
         9 . The scanner of    claim 1   , further comprising an optical bench mounted along the central reference axis, wherein the optical bench includes a shock-mounted support structure upon which the stationary optically reflective surfaces are mounted.  
     
     
         10 . The scanner of    claim 1   , wherein the optical receiver comprises a photodetector.  
     
     
         11 . The scanner of    claim 10   , wherein the photodetector is located on a circuit board, at a height above the beam sweeping mechanism, substantially within the central reference plane.  
     
     
         12 . The scanner of    claim 1   , wherein said code symbol is a bar code symbol.  
     
     
         13 . The scanner of    claim 1   , wherein the optical collecting element is a light collecting mirror having a focal distance, substantially at which said optical receiver is located.  
     
     
         14 . The scanner of    claim 1   , wherein 
 each scan line in a first group of scan lines is substantially parallel to each other scan line in said first group of scan lines, and    each scan line in a second group of scan lines is substantially parallel to each other scan line in said second group of scan lines.    
     
     
         15 . An automatic optical scanning system comprising: 
 a housing having an optically admissive aperture through which optical energy of at least one wavelength can exit and enter into the housing;    an object detector in the housing, for detecting an object located in a scanning volume extending externally from the housing, and automatically generating an activation signal in response to the detection of the object located therein;    an activatable scan data reading mechanism in the housing, for reading scan data from a detected object located in the scanning volume, the scan data reading mechanism including:    an optical beam generator for generating a beam of optical energy and directing the beam through the optically admissive aperture and into the scanning volume,    a beam scanner for repeatedly scanning the beam so as to produce a collimated scanning pattern of approximately columnar extent within the scanning volume, for scanning a code symbol on the detected object presented therein,    an optical detector for detecting optical energy reflected off the bar code symbol and passing through the optically admissive aperture as the beam is repeatedly scanned within the scanning volume, and    a receiver for automatically producing scan data indicative of the detected optical energy;    an activatable scan data processor for processing produced scan data so as to detect and decode said bar code symbol on the detected object, and automatically producing symbol character data representative of the decoded bar code symbol; and    a control mechanism for controlling the operation of the automatic bar code symbol reading system;    wherein the housing permits the user to control the direction of the projection axis to align said approximately columnar scanning volume with the bar code symbol on the object to be scanned.    
     
     
         16 . The scanning system of    claim 15   , wherein the optical beam generator comprises a laser diode.  
     
     
         17 . The scanning system of    claim 15   , wherein the bar code symbol has first and second envelope borders, and wherein said scan data processor comprises a detector adapted to detect the first and second envelope borders of said bar code symbol, and a mechanism for decoding said detected bar code symbol.  
     
     
         18 . The scanning system of    claim 15   , wherein the object detector comprises a receiver for receiving optical energy reflected from an object within an object detection field defined external to the housing and having an essentially volumetric extent, and 
 wherein the collimated scanning pattern is characterized by at least one scanning plane having an essentially planar extent, and    wherein the object detection field spatially encompasses at least a portion of the collimated scanning pattern.    
     
     
         19 . The laser scanning system of    claim 15   , wherein the optical beam generator is operated in a pulsed mode so as to generate a pulsed beam, which is directed through the optically admissive aperture and repeatedly scanned across the collimated scanning pattern and the bar code symbol on the detected object.  
     
     
         20 . The scanning system of    claim 19   , wherein the object detector includes 
 a transmitter for transmitting a pulsed signal through a first optical element and into the scanning volume,    a signal receiver for receiving the transmitted pulse signal reflected off the object in the scanning volume, and    a signal comparator for comparing the received pulse signal with the transmitted pulse signal and automatically generating an activation signal indicative of the presence of the object in the scanning volume.    
     
     
         21 . The scanning system of    claim 15   , wherein the housing comprises a head portion and a handle portion, and wherein the object detector and the activatable scan data processor are located in the head portion.  
     
     
         22 . The scanning system of    claim 20   , wherein the transmitter comprises an infra-red light source in the housing for producing an infra-red light pulse which is transmitted through the first optical element into the scanning volume, and wherein the receiver comprises an infra-red light detector and a second optical element for focusing reflected infra-red light pulses onto the infrared light detector.  
     
     
         23 . A scanner comprising: 
 (a) a housing having an optically admissive window through which optical energy of at least one wavelength can exit said hand-supportable housing, travel towards an object bearing a code symbol and reflect therefrom, and at least a portion of the reflected optical energy travelling back through the optically admissive window to enter the housing; at least some of the exited optical energy and at least some of the reflected optical energy traveling approximately in a longitudinal direction extending along a central reference axis;    (b) an optical energy beam producing mechanism disposed within the housing for producing a beam of optical energy;    (c) a beam sweeping mechanism mounted within the housing for rotation about a rotational axis intersecting the central reference axis, where the intersection of the rotational axis and the central reference axis defines a central reference plane;    the beam sweeping mechanism having a plurality of rotating optically reflective surfaces each being disposed at a different acute angle with respect to the rotational axis, for sequentially sweeping the beam about the rotational axis along a plurality of different paths;    (d) a stationary array comprised of a plurality of stationary optically reflective surfaces mounted within the housing;    wherein at least two of the plurality of the stationary optically reflective surfaces are symmetrically disposed on opposite sides of the central reference plane, and adjacent to the beam sweeping mechanism;    (e) an optical energy collection mechanism disposed within the housing, and including    (1) an optical collection element, mounted along the central reference plane and adjacent at least two of the stationary optically reflective surfaces, for allowing the beam produced from the beam producing mechanism to pass along a portion of the central reference plane, to the beam sweeping mechanism, for sweeping about the rotational axis thereof along the plurality of different paths, and    (2) an optical receiver for receiving optical energy from the optical collection element at a point substantially within the central reference plane, and detecting the received optical energy and producing an electrical signal indicative of the detected optical energy;    (f) a signal processor for processing the electrical signal and producing scan data representative of a scanned code symbol; and    (g) a control mechanism for controlling the operation of the scanner so that, during scanner operation, the beam produced from the beam producing mechanism passes along a portion of the central reference plane, to at least one of the rotating light reflective surfaces of the beam sweeping mechanism, and as the beam sequentially reflects off a plurality of the rotating optically reflective surfaces, the beam is repeatedly swept across a plurality of the stationary optically reflective surfaces thereby producing a plurality of groups of plural scan lines, respectively, which are projected out through the optically admissive window and intersect about a projection axis within a collimated scanning volume having an approximately columnar extent and extending from adjacent said optically admissive window to at least about six inches therefrom so as to produce a collimated projected scanning pattern.    
     
     
         24 . The scanner of    claim 23    further comprising a mechanism adapted for intuitive aiming of the housing such that: 
 (i) the housing is supportable relative to an object bearing a code symbol wherein, when a code symbol is presented within the collimated scanning volume:  
 (i) the code symbol is scanned omnidirectionally by the collimated scanning pattern,  
 (ii) at least a portion of the optical energy reflected from said scanned code symbol is directed through said optically admissive window, reflected off at least one of the stationary optically reflective surfaces, and then reflected off at least one of the rotating optically reflective surfaces of the beam sweeping mechanism, and  
 (iii) thereafter the reflected optical energy is collected by the optical collection element, and received by the optical receiver for detection, whereupon the electrical signal is produced for processing by the signal processor;  
 and wherein the housing is adapted to permit a user to control the direction of said projection axis so as to align the collimated scanning volume with the bar code symbol on the object to be scanned.