Laser scanning system and scanning method for reading bar codes

• US 5,235,167 A
• Filed: 06/14/1991
• Issued: 08/10/1993
• Est. Priority Date: 10/21/1988
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Goren, David P., Spitz, Glenn S., Dvorkis, Paul
• Primary Examiner(s): Shepperd, John
• Assistant Examiner(s): Chin, Esther
• Application Number:
  US07/715,267
• Time in Patent Office: 788 Days
• Field of Search: 235/467, 235/470, 235/462
• US Class Current: 235/462.21
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 2207/1016 Motor control or optical moving unit control
• CPC Class Codes: G06K 2207/1017 Programmable
• CPC Class Codes: G06K 2207/1018 Source control
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10633 by oscillation
• CPC Class Codes: G06K 7/10643 Activating means
• CPC Class Codes: G06K 7/10653 using flexible or piezoelectric means
• CPC Class Codes: G06K 7/10673 Parallel lines
• CPC Class Codes: G06K 7/10693 for omnidirectional scanning
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10811 Focalisation
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/10871 randomly oriented data-fields, code-marks therefore, e.g. concentric circles-code
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: G06K 7/10891 the scanner to be worn on a finger or on a wrist
• CPC Class Codes: G06K 7/109 adaptations to make the hand-held scanner useable as a fixed scanner

Abstract

A system for reading bar code symbols or the like, including one- or two-dimensional bar code symbols having a scanner for generating a laser beam directed toward a target and producing a narrow first raster scanning pattern that enables the user to manually aim and direct the beam to the location desired by the user and a second raster scanning pattern that increases in height which sweeps an entire symbol to be read, and a detector for receiving reflected light from such symbol to produce electrical signals corresponding to data represented by such symbol.

Claims

1. A device for reading bar code symbols of the like, comprising:

a) a light source for generating a light beam directed toward a symbol to be read in the form of a raster scan pattern of adjustable height;

b) a light detector receiving reflected light from said symbol and generating electrical signals responsive to said reflected light;

c) a control circuit for modifying the height of said scan pattern in response to said electrical signals from said detector.

2. A device according to claim 1, wherein said control circuit is responsive to whether said electrical signals represent a pattern of a bar code symbol.

3. A device according to claim 2, wherein said control circuit switches said raster scan pattern from a narrow height mode to a wide height mode when said electrical signals represent the pattern of a bar code.

4. A bar code reader comprising:

a) a light beam scanner generating a light beam directed toward a symbol to be read and moving said light beam along said symbol in a raster scanning pattern;

b) a light detector receiving reflected light from said symbol and generating electrical signals responsive to said reflected light;

c) means for controlling the height and/or path shape of said scanning pattern in response to said electric signals.

5. A device according to claim 4, wherein said light beam scanner moves said light beam on a first scan path or on a second scan path in response to said electrical signals.

6. A device according to claim 5, wherein said first and second scan paths are selected by changing the scanning angle of said raster scanning pattern.

7. A method of scanning bar code symbols or the like comprising the steps of:

a) providing a relatively bright, narrow rectangular laser raster scanning pattern for enabling the user to aim and direct the beam toward a bar code symbol to be read;

b) scanning said symbol;

c) detecting light reflected from the symbol and generating an electrical signal in response to said reflected light; and

d) modifying the height of said raster scan pattern in response to said electrical signal.

8. A method according to claim 7, wherein said step of modifying includes changing the shape of said path.

9. A method according to claim 8, further including the step of determining whether or not said electrical signal exhibits characteristics of a bar code signal, and wherein said step of modifying is performed in response to the results from said step of determining.

10. A method according to claim 9 wherein said step of determining includes deciding whether said bar code symbol is a one dimensional or a two dimensional bar code symbol.

11. A method according to claim 9, wherein said step of determining includes deciding if the scanning direction is substantially orthogonal to the bars of a two dimensional bar code symbol.

12. A scanner for electro-optically reading coded indicia that may include linear bar code symbols, or two dimensional symbologies in which data or information is represented in the form of bars or elements of various widths arrayed in rows, one row adjacent to and beneath another row, with each row including a plurality of codewords of information, and each codeword representing at least one information bearing character, comprising:

a) means for directing light from a laser in a pattern of scanning lines at an indicium to be read for reflection therefrom;

b) means for detecting at least a portion of the light reflected from the indicium;

c) means for determining from the reflected light from successive scanning lines whether the indicium is a portion of a linear bar code symbol, or a portion of a two dimensional symbology; and

d) means for decoding the indicium.

13. A system for reading bar code symbols or the like, comprising

scanning means for generating a laser beam directed toward a target and producing a first scanning pattern that enables the user to manually aim and direct the beam to the location desired by the user and a relatively larger second scanning pattern in the form of a raster that sweeps an entire symbol to be read,

means for changing from said first scanning pattern to said second scanning pattern, and

detection means for receiving reflected light from such symbol to produce electrical signals corresponding to data represented by such symbol.

14. A system according to claim 13 wherein said scanning means includes a semiconductor laser light source to produce said laser beam, and further comprising a gun-shaped housing having an exit port, wherein said scanning means and said detection means are located in said housing, and said housing includes a handle portion of a size designed to be gripped by a user, and a barrel portion connected to the handle portion so as to enable the user to manually aim and direct the laser beam to the target.

15. A system as defined in claim 14, further comprising manually actuatable trigger means on said housing for initiating said first scanning pattern, and indicator means to inform the user that the housing is positioned in the correct working range for reading a bar code symbol.

16. The system as defined in claim 15, wherein said trigger means includes a multi-purpose trigger operatively connected to the scanning means to select between the first scanning pattern and the relatively larger second scanning pattern.

17. The system as defined in claim 13, wherein said symbol includes at least two rows of bar patterns, and said relatively larger second scanning pattern covers the entire symbol with at least two scan lines per row of bar patterns during the reading operation.

18. A system as defined in claim 13, wherein the number of scan lines in said first scanning pattern is substantially equal to the number of scan lines in said relatively larger second scanning pattern.

19. A system as defined in claim 13, wherein said means for initiating said second scanning pattern occurs at a predetermined time after said first scanning pattern is initiated.

20. A system as defined in claim 13, wherein said means for changing to said second scanning pattern is activated if said detection means recognizes that a bar code is being scanned.

21. A system as defined in claim 13, wherein said means for changing to said second scanning pattern is activated if the position of the system is within the proper range and orientation with resect to the symbol.

22. A system as defined in claim 13, wherein said first scanning pattern is a raster scanning pattern.

23. A system for reading bar code symbols or the like, comprising scanning means for generating a laser beam directed toward a target producing a first scanning pattern that has a reflectivity on the target that enables the user to manually aim and direct the beam to the location desired by the user on the target and a sequence of different subsequent scanning patterns that each progressively increase height including a scanning pattern that sweeps the entire symbol to be read, and detection means for receiving reflected light from such symbol to produce electrical signals corresponding to data represented by such symbol.

24. A system as defined in claim 23, wherein said first and subsequent scanning patterns are raster scanning patterns.

25. A system as defined in claim 23, wherein said system is hand-held.

26. A system for reading bar code symbols or the like, comprising

scanning means for generating a laser beam directed toward a target and producing a first raster scanning pattern for a first period of time and subsequently a relatively larger

second raster scanning pattern that sweeps the entire height of a symbol to be read;

means for changing the scanning pattern from said first to said second pattern, and

detection means for receiving reflected light from such symbol to produce electrical signals corresponding to data represented by such symbol.

27. The system as defined in claim 26, wherein said symbol includes at least two rows of bar patterns, the number of scan lines in said first scanning pattern is substantially equal to the number of scan lines in said relatively larger second scanning pattern, and

said relatively larger second raster pattern covers the entire symbol with at least two scan lines per row of bar patterns during the reading operation.

28. A system as defined in claim 26, wherein a sequence of larger raster scanning patterns is produced commencing at a predetermined time after said first scanning pattern.

29. A system for reading bar code symbols or the like, comprising

scanning means for generating a laser beam directed toward a target and producing a sequence of two-dimensional different scanning patterns that initially enables the user to position the beam to scan in a direction corresponding to the rows of a multidimensional bar code symbol, and

detection means for receiving reflected light from such symbol from successive scanning patterns to produce electrical signals corresponding to data represented by such symbol until each of said rows of said symbol has been read.

30. A system according to claim 29, wherein said scanning means includes a semiconductor laser light source to produce said laser beam, and further comprising a gun-shaped housing having an exit port, wherein said scanning means and said detection means are located in said housing, and said housing includes a handle portion of a size designed to be gripped by a user, and a barrel portion connected to the handle portion so as to enable the user to manually aim and direct the laser beam to the target.

31. A system as defined in claim 29, further comprising manually actuatable trigger means on said housing for initiating a first scanning pattern, and indicator means to inform the user that the housing is positioned in the correct working range for reading a bar code symbol.

32. The system as defined in claim 31, wherein said trigger means includes a multi-position trigger operatively connected to the scanning means to select between a first scanning pattern and a second scanning pattern.

33. The system as defined in claim 29, wherein said multidimensional bar code symbol includes at least two rows of bar patterns, and at least one of said scanning patterns covers the entire symbol with at least two scan lines per row of bar patterns.

34. A system as defined in claim 29, wherein the number of scan lines in said first scanning pattern is substantially equal to the number of scan lines in a second scanning pattern.

35. A system as defined in claim 29, wherein said means for initiating a second scanning pattern occurs at a predetermined time after said first scanning pattern is initiated.

36. A system as defined in claim 29, wherein said means for changing to said second scanning pattern is actuated if said detection means recognizes that a bar code is being scanned.

37. A system as defined in claim 29, wherein said means for changing to said second scanning pattern is actuated if the position of the system is within the proper range and orientation with respect to the symbol.

38. In a scanning system for reading bar codes, means for initially scanning at least a portion of the bar code to be read to detect if the same is a linear or multidimensional code and generating a signal indicative thereof, and means actuated by said signal for adjusting the scan pattern to scan such detected type of code.

39. The system as defined in claim 38, wherein said multidimensional bar code symbol includes at least two rows of bar patterns, and the adjusted scan pattern covers the entire symbol with at least two scan lines per row of bar patterns.

40. A system as defined in claim 38, wherein said means for adjusting the scan pattern is actuated if said detection means recognizes that a multidimensional bar code is being scanned.

41. A system as defined in claim 38, wherein said means for adjusting the scan pattern is actuated if the position of the system is within the proper range and orientation with respect to the symbol.

42. A method for electro-optically reading light-reflective indicia, comprising:

scanning means for protecting light on an indicium to be read, and for scanning the indicium with a scan pattern having a first scan characteristic;

detector means for detecting a portion of the light reflected off the indicium, and for generating electrical signals indicative of the detected light portion;

processor means for processing the electrical signals to determine whether the indicium has a predetermined feature; and

changing means responsive to the determination that the indicium has the predetermined feature, for changing the scan pattern to have a different, second characteristic.

43. A system as defined in claim 42, wherein the predetermined feature of the indicium is that the indicium is a one-dimensional bar code symbol having parts of different light reflectivity arranged along a row.

44. A system as defined in claim 42, wherein the predetermined feature of the indicium is that the indicium is a two-dimensional bar code symbol having parts of different light reflectively arranged along multiple rows.

45. A system as defined in claim 42, wherein the indicium is a bar code symbol having parts of different light reflectivity arranged along a scan direction, and having a symbol height extending along a transverse direction normal to the scan direction;

and wherein the first scan characteristic has a reduced scan height less than said symbol height along the transverse direction; and

wherein the second scan characteristic has an enlarged scan height greater than said symbol height along the transverse direction.

46. A system as defined in claim 42, wherein the indicium is a bar code symbol having parts of different light reflectivity arranged along a scan direction;

and wherein the first scan characteristics extends along a first axis inclined relative to the scan direction; and

wherein the second scan characteristics along a second axis generally parallel to the scan direction.

47. A method system for reading bar code symbols or the like, comprising the steps of:

generating a laser beam directed toward a target and producing a first scanning pattern that enables the user to manually aim and direct the beam to the location desired by the

user and a relatively larger second scanning pattern in the form of a raster that sweeps an entire symbol to be read,

changing from said first scanning pattern to said second scanning pattern, and

receiving reflected light from such symbol to produce electrical signals corresponding to data represented by such symbol.

48. A system as defined in claim 47, further comprising the step of actuating trigger means on a housing for initiating said first scanning pattern.

49. A method for reading bar code symbols or the like, comprising the steps of generating a laser beam directed toward a target and producing a first scanning pattern that has a reflectivity on the target that enables the user to manually aim and direct the beam to the location desired by the user on the target, generating a sequence of different subsequent scanning patterns that each progressively increase in height including a scanning pattern that sweeps the entire symbol to be read, and receiving reflected light from such symbol to produce electrical signals corresponding to data represented by such symbol.

50. The method as defined in claim 49, further comprising the step of actuating a multi-purpose trigger to select between the first scanning pattern and a subsequent scanning pattern.

51. The method as defined in claim 49, wherein said target includes a bar code symbol with at least two rows of bar patterns, and one of said subsequent scanning patterns covers the entire symbol with at least two scan lines per row of bar patterns during the reading operation.

52. A system as defined in claim 49, wherein the number of scan lines in said first scanning pattern is substantially equal to the number of scan lines in said subsequent scanning patterns.

53. A method as defined in claim 49, wherein a second scanning pattern is initiated at a predetermined time after said first scanning pattern is initiated.

54. A method as defined in claim 49, wherein a second scanning pattern is initiated if a bar code is being scanned.

55. A method as defined in claim 49, wherein a second scanning pattern is initiated if the location of the scanning system is within the proper range and orientation with respect to the symbol on the target.

56. A method for reading bar code symbols or the like, comprising the steps of

generating a laser beam directed toward a target and producing a first raster scanning pattern for a first period of time and subsequently a relatively larger second raster scanning pattern that sweeps the entire height of a symbol to be read;

changing the scanning pattern from said first to said second pattern, and

receiving reflected light from such symbol to produce electrical signals corresponding to data represented by such symbol.

57. The method as defined in claim 56, wherein said symbol includes at least two rows of bar patterns, the number of scan lines in said first scanning pattern being substantially equal to the number of scan lines in said relatively larger second scanning pattern, and

said relatively larger second raster pattern covers the entire symbol with at least two scan lines per row of bar patterns during the reading operation.

58. A method as defined in claim 56, wherein a sequence of larger raster scanning patterns is produced commencing at a predetermined time after said first scanning pattern.

59. A method as defined in claim 56, wherein said step of changing the scanning pattern is initiated if a bar code is being scanned.

60. A method as defined in claim 56, wherein said step of changing said scanning pattern is initiated if the position of the system is within the proper range and orientation with respect to the symbol.

61. A method for reading bar code symbols or the like, comprising

generating a laser beam directed toward a target and producing a sequence of two-dimensional different scanning patterns that initially enables the user to position the beam to scan in a direction corresponding to the rows of a multi-dimensional bar code symbol, and

receiving reflected light from such symbol from said sequence of scanning patterns to produce electrical signals corresponding to data represented by such symbol until each of said rows of said symbol has been read.

62. The method as defined in claim 61, further comprising the step of actuating a multi-purpose trigger to select between the first scanning pattern and a subsequent scanning pattern.

63. The method as defined in claim 61, wherein said target includes a bar code symbol with at least two rows of bar patterns, and one at said subsequent scanning patterns covers the entire symbol with at least two scan lines per row of bar patterns during the reading operation.

64. A system as defined in claim 61, wherein the number of scan lines in said first scanning pattern is substantially equal to the number of scan lines in said subsequent scanning patterns.

65. A system as defined in claim 61, wherein a second scanning pattern is initiated at a predetermined time after said first scanning pattern is initiated.

66. A system as defined in claim 61, wherein a second scanning pattern is initiated if a bar code is being scanned.

67. A system as defined in claim 61, wherein a second scanning pattern is initiated if the location of the scanning system is within the proper range and orientation with respect to the symbol on the target.

68. A method of scanning bar code symbols or the like comprising the steps of:

a) providing a relatively bright scanning pattern for enabling the user to aim and direct the beam toward a bar code symbol to be read;

b) scanning said symbol;

c) detecting light reflected from the symbol and generating an electrical signal in response to said reflected light; and

d) modifying the scanning pattern to product a raster scan pattern in response to said electrical signal.

69. A method according to claim 68, wherein said step of modifying includes changing the shape of said path from a narrow raster scan pattern to a raster scan pattern with greater height.

70. A method according to claim 68, further including the step of determining whether or not said electrical signal exhibits characteristics of a bar code signal, and wherein said step of modifying is performed in response to the results from said step of determining.

71. A method according to claim 70 wherein said step of determining includes deciding whether said bar code symbol is a one dimensional or a two dimensional bar code symbol.

72. A method according to claim 70, wherein said step of determining includes deciding if the scanning direction is substantially orthogonal to the bars of a two dimensional bar code symbol.