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

• US 6,398,112 B1
• Filed: 03/31/2000
• Issued: 06/04/2002
• Est. Priority Date: 06/30/1994
• Status: Expired due to Fees

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Barkan, Edward, Katz, Joseph, Li, Yajun, Swartz, Jerome
• Primary Examiner(s): LE, THIEN MINH
• Application Number:
  US09/540,404
• Time in Patent Office: 795 Days
• Field of Search: 235/462.01, 235/472.01, 235/462-7-4, 235/462.25, 235/462.32, 235/462.42, 235/462.4
• US Class Current: 235/462.01
• 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 portable scanning head supported by a user for reading a bar code symbol on a target, comprising:

a) a first assembly, including a visible laser light source for emitting a laser beam, and a scanner for scanning the laser beam so as to visually illuminate the target with a scanning line, thereby allowing the user to aim the head at the symbol to be read; and

b) a second assembly, including a solid state sensor for imaging reflected light along two mutually orthogonal directions over a plane from the target, and for generating an electrical signal indicative of spatial intensity variations of the bar code symbol.

2. A reader for electro-optically reading indicia having parts of different light reflectivity, comprising:

a) a first assembly, including a visible laser light source for directing a laser beam toward an indicium for rendering visible at least a target area on the indicium; and

b) a second reader assembly, including a solid state sensor for imaging light reflected from the indicium along two mutually orthogonal directions over a plane, and for generating an electrical signal indicative of the imaged light.

3. The reader of claim 2, wherein the first assembly includes a scanner for sweeping the laser beam over the indicium.

4. The reader of claim 2, wherein the sensor is a charge coupled device array.

5. The reader of claim 2, wherein the sensor is a charge coupled device array having imaging elements arranged along the two orthogonal directions, for imaging the reflected light over a two-dimensional field of view.

6. The reader of claim 2, wherein the assemblies are independently operable.

7. The reader of claim 2, wherein the first assembly includes a scanner for sweeping the laser beam over the indicium to read the indicium;

and wherein the second reader assembly is operative for scanning a field of view of the sensor over the indicium to read the indicium upon failure of the first assembly to read the indicium.

8. The reader of claim 2, wherein the second reader assembly is operative for scanning a field of view over the indicium to read the indicium;

and wherein the first assembly includes a scanner for sweeping the light beam over the indicium to read the indicium upon failure of the second reader assembly to read the indicium.

9. The reader of claim 7;

and further comprising a controller for initially enabling only one of the assemblies to read the indicium, and for subsequently enabling only the other of the assemblies to read the indicium upon failure of said one of the assemblies to read the indicium.

10. The reader of claim 9;

and further comprising a user-selectable input for selecting which of the assemblies is the one to be initially enabled by the controller.

11. A bar code reader for reading symbols of differing light reflectivity, comprising:

a) a first assembly, including a visible laser source for generating a laser beam to visually illuminate sequential portions of each symbol for rendering visible at least a target area on the respective symbol; and

b) a second reader assembly, including a solid state sensor for imaging reflected light along two mutually orthogonal directions over a plane from each symbol, and for generating an electrical signal responsive to the imaged light indicative of the respective symbol.

12. A method of reading a bar code symbol having parts of different light reflectivity on a target, comprising the steps of:

a) supporting a portable reader in a user'"'"'s hand;

b) emitting a visible scanning laser light beam from the reader so that the beam is scanned on a path to the target to enable the user to aim the reader with respect to the bar code symbol; and

c) imaging reflected light along two mutually orthogonal directions over a plane from the bar code symbol on a solid state sensor to generate an electric signal indicative of imaged spatial light intensity variations of the bar code symbol, and to process the electrical signal to produce information represented by the bar code symbol.

13. A method of electro-optically reading indicia having parts of different light reflectivity, comprising the steps of:

a) directing a laser beam from a visible laser light source of a first assembly toward an indicium for rendering visible at least a target area on the indicium; and

b) imaging light reflected from the indicium along two mutually orthogonal directions over a plane by a solid state sensor of a second reader assembly, and generating an electrical signal indicative of the imaged light.

14. The method of claim 13;

and further comprising the step of sweeping the laser beam from the light source over the indicium to illuminate the indicium with an aiming line.

15. The method of claim 13, wherein the imaging step is performed by a charge coupled device.

16. The method of claim 13, wherein the imaging step is performed over a two-dimensional field of view of the sensor.

17. The method of claim 13;

and further comprising the step of sweeping the laser beam over the indicium to read the indicium.

18. The method of claim 17;

and further comprising the step of initially enabling only one of the assemblies to read the indicium and, upon failure of the one assembly to read the indicium, subsequently enabling only the other of the reader assemblies to read the indicium.

19. The method of claim 18;

and further comprising the step of selecting by a user which of the assemblies is the one to be initially enabled.