Apparatus and method for reading indicia using charge coupled device and scanning laser beam technology

• US 5,672,858 A
• Filed: 06/30/1994
• Issued: 09/30/1997
• Est. Priority Date: 06/30/1994
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Li, Yajun, Katz, Joseph, Swartz, Jerome, McGlynn, Daniel
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): FILIPEK, JEFFER
• Application Number:
  US08/269,170
• Time in Patent Office: 1,188 Days
• Field of Search: 235/462, 235/472
• US Class Current: 235/462.04
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 2207/1018 Source control
• CPC Class Codes: G06K 7/10811 Focalisation
• CPC Class Codes: G06K 7/1092 sensing by means of TV-scanning

Abstract

A scanning device for reading indicia of differing light reflectivity, including bar code or matrix array symbols, has a single light emitter, such as a laser or light emitting diode, for generating a scanning light beam to visually illuminate sequential portions of the indicia. A sensor, such as a charge coupled or other solid state imaging device, simultaneously detects light reflected from portions of the indicia and generates an electrical signal representative of the spacial intensity variations the portions of the indicia. The scanning device may also include an ambient light sensor, and a second light emitter for use only in aiming or orienting the scanning device. A photodetector may also be provided to separately detect one symbol virtually simultaneous with the detection of another symbol by the sensor or to provide dual modalities. A method for reading indicia is also provided.

Claims

1. A scanning device for reading indicia of differing light reflectivity comprising;

a single light emitter for generating a scanning light beam to visually illuminate sequential portions of the indicia;

a sensor for detecting light reflected from portions of the indicia by scanning a field of view and for generating an electrical signal representative of spatial intensity variations of said portions of the indicia; and

a controller for automatically varying the rate of scanning of said sensor to read said indicia.

2. A device as defined in claim 1, wherein said single light emitter includes a laser diode.

3. A device as defined in claim 1, wherein said sensor is a linear array of charge coupled devices.

4. A device as defined in claim 1, wherein said sensor is a two-dimensional array of solid state imaging devices.

5. A device as defined in claim 1, further comprising an ambient light sensor for detecting the level of the ambient light in the field of view and for producing an output signal if the ambient light level is below a threshold value.

6. A device as defined in claim 5, further comprising means for activating said light emitter, and wherein said means for activating said light emitter is responsive to said output signal.

7. A device as defined in claim 6, wherein said means for activating said light emitter is also responsive to said electrical signal.

8. A device as defined in claim 1, wherein said indicia is a matrix code or bar code symbol in which information is encoded in a two-dimensional pattern.

9. A device as defined in claim 1, further comprising selection means for deactivating said single light emitter if the indicia is a symbol of a certain symbology category.

10. A device as defined in claim 1, wherein said electrical signal is representative of light produced by said single light emitter reflected from said indicia.

11. A device as defined in claim 1, wherein said electrical signal is representative of the ambient light reflected from said indicia.

12. A device as defined in claim 1, wherein the scan rate at which said sensor scans the field of view is faster than that of said scanning light beam.

13. A device as defined in claim 1, wherein said sensor scans a field of view at a scan rate substantially slower than the rate of scanning of said light beam.

14. A device as defined in claim 1, wherein said sensor periodically scans the field of view and then ceases to scan the field of view for a period of time.

15. A device as defined in claim 1, further comprising processing means including a symbology discriminator for discriminating between indicia of different symbology types.

16. A device as defined in claim 15, wherein one of said symbology types is a matrix array of geometric shapes.

17. A device as defined in claim 16, wherein said single light emitter is deactivated upon said processing means detecting a matrix array symbol.

18. A device as defined in claim 1, wherein said light emitter and said sensor are disposed in a hand-held housing.

19. A scanning device for reading indicia of differing light reflectivity comprising;

a single light emitter for generating a scanning light beam to visually illuminate sequential portions of the indicia;

an imager for detecting light reflected from portions of the indicia and for generating an electrical signal representative of spatial intensity variations of said portions of the indicia; and

means for processing said electrical signal to determine whether the indicia is a linear or multidimensional symbol.

20. A scanning device for reading indicia having parts of different light reflectivity comprising:

a light source for generating a visible light beam;

an optical element for directing said visible light beam such that said visible light beam forms a scan line across said indicia;

a sensor, including an array of individual detection elements, for detecting the reflected light from said indicia by imaging a field of view and for generating an electrical signal representing the spatial intensity variations of said indicia; and

a controller operable to control said optical element to vary the scanning rate of said light beam across said indicia.

21. A scanning device according to claim 20, further comprising integrating means for processing the output of each of the individual detection elements to produce a single output signal.

22. A scanning device according to claim 21, wherein said individual detection elements are scanned at a variable scanning rate.

23. A scanning device according to claim 20, further comprising auto-focus optics for receiving the reflected light and adjusting the focal point of the image on the sensor array.

24. A scanning device according to claim 20, further comprising a light weight portable housing containing said light source, said optical element and said sensor.

25. A device as defined in claim 24, further comprising transmitter means in the housing for transmitting information through the air to a receiver located remotely from the device.

26. A device as defined in claim 20, wherein said individual detection elements are scanned at a scanning rate, and further comprising actuatable control means in the housing to change the scanning rate of the individual detection elements.

27. A method for reading indicia of differing light reflectivity comprising;

generating a single scanning light beam to visually illuminate sequential portions of the indicia;

imaging light reflected from portions of the indicia including the scanned field of view;

automatically varying either the rate of said scanning light beam, or the imaging of said field of view, or both, to read the indicia; and

generating an electrical signal representative of spatial intensity variations of said portions of the indicia.

28. A method as defined in claim 27, wherein said single scanning light beam is a laser light beam.

29. A method as defined in claim 27, further comprising the steps of detecting the level of the ambient light in a field of view and producing an output signal if the ambient light level is below a threshold value.

30. A method as defined in claim 29, further comprising the step of generating said single scanning light beam in response to said output signal.

31. A method as defined in claim 30, wherein said step of generating said single scanning light beam is also responsive to said electrical signal.

32. A method as defined in claim 27, wherein said indicia is a matrix code or bar code symbol in which information is encoded in a two-dimensional pattern.

34. A method as defined in claim 27, further comprising the step of terminating the generating of said light beam if the symbol is of a certain symbology category.

35. A method as defined in claim 27, wherein said electrical signal is representative of light from said single light beam reflected from said indicia.

36. A method as defined in claim 27, wherein said electrical signal is representative of ambient light reflected from said indicia.

37. A method as defined in claim 27, wherein said rate of imaging is faster than the rate of scanning of said light beam.

38. A method as defined in claim 27, wherein said rate of imaging is substantially slower than the rate of scanning of said light beam.

39. A method as defined in claim 27, wherein said imaging periodically images the field of view and then ceases to image the field of view for a period of time.

40. A method as defined in claim 27, further comprising the steps of discriminating between indicia of different symbology types.

41. A method as defined in claim 40, wherein one of said symbology types is a matrix array of geometric shapes.

42. A method as defined in claim 41, wherein said generating of said single light beam is terminated upon detecting a matrix array symbol during said processing.

33. A method for reading indicia of differing light reflectivity comprising:

generating a single scanning light beam to visually illuminate sequential portions of the indicia;

simultaneously imaging light reflected from portions of the indicia; and

generating an electrical signal representative of spatial intensity variations of said portions of the indicia; and

processing said electrical signal to determine whether the indicia is a linear or multidimensional symbol.

43. A method for reading indicia having parts of different light reflectivity comprising:

generating a visible light beam;

directing said visible light beam such that said visible light beam forms a scan line across said indicia at a first scan rate;

imaging the reflected light from said indicia by scanning a field of view including the indicia at a second scan rate;

varying at least one of said first scan rate and said second scan rate to obtain a read of said indicia; and

generating an electrical signal representing the spatial intensity variations of said indicia.

44. A method according to claim 43, wherein multiple output signals are provided by said imaging, and further comprising the step of processing the multiple output signals to generate a single output signal.

45. A method according to claim 43, further comprising the steps of receiving the reflected light and adjusting said imaging in response to the received reflected light.

46. A method as defined in claim 43, further comprising the step of transmitting information represented by said electrical signal through the air to a remote location.