Bar code readers having selectable optical elements

• US 6,024,283 A
• Filed: 09/17/1997
• Issued: 02/15/2000
• Est. Priority Date: 02/27/1995
• Status: Expired due to Fees

• Current Assignee: Concepts Implementation Group Main Street USA
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: McGlynn, Daniel R., Campanelli, Joseph, Metlitsky, Boris, Dvorkis, Paul
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): TREMBLAY, MARK STEPHEN
• Application Number:
  US08/999,956
• Time in Patent Office: 881 Days
• Field of Search: 235/455, 235/467, 235/462, 235/472, 235/462.22, 235/462.32, 235/462.41, 250/205, 359/72
• US Class Current: 235/462.32
• CPC Class Codes: G06K 7/10574 Multiple sources
• CPC Class Codes: G06K 7/10643 Activating means
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10742 including a diffuser for diffusing the light from the light source to create substantially uniform illumination of the target record carrier
• CPC Class Codes: G06K 7/10811 Focalisation
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

A bar code reader for reading a symbol located at a distance from the laser comprises an array of groups of reading elements and an array of selectable liquid crystal elements. Each of the groups of reading elements have an associated predetermined operating focal distance. At least one liquid crystal element corresponds to each group of reading elements. In the bar code reader, a device activates a selected liquid crystal element to transmit light to a selected group of reading elements. In this way, the reading elements can operate at a predetermined, fixed operating focal distance.

Claims

1. A bar code reader for reading a bar code symbol, comprising:

an array of detector elements;

an array of selectable optical elements disposed proximate to the array of detector elements, wherein the optical elements correspond to the detector elements;

an array of focusing lenses positioned between the array of selectable optical elements and the array of detector elements; and

means for selecting an optical element to cause at least one of the corresponding detector elements associated with the optical element to receive light reflected from the bar code symbol in focus.

2. A bar code reader for reading a bar code symbol according to claim 1, wherein said means for selecting selects based upon a distance between the bar code symbol and the detector elements.

3. The bar code reader according to claim 1, wherein the array of focusing lenses is attached to the array of detector elements.

4. The bar code reader according to claim 1, wherein the optical elements selectively transmit light.

5. The bar code reader according to claim 4, wherein the optical elements are liquid crystal elements.

6. The bar code reader according to claim 1, wherein the optical elements selectively reflect light.

7. The bar code reader according to claim 6, wherein the optical elements are miniature mirror elements.

8. The bar code reader according to claim 1, wherein the means for selecting causes the detector elements to receive light such that less than the entire bar code symbol is detected at one time.

9. The bar code reader according to claim 1, wherein the means for selecting causes the detector elements to receive light such that the entire bar code symbol is detected at one time.

10. The bar code reader according to claim 1, further comprising a light source for emitting a light beam onto the bar code symbol.

11. The bar code reader according to claim 1, wherein the array of optical elements is disposed in a fixed relation with respect to the array of detector elements.

12. The bar code reader according to claim 1, wherein the detector elements are charge coupled devices.

13. A bar code reader for reading a bar code symbol, comprising:

an array of detector elements;

an array of selectable liquid crystal elements optically coupled to the array of detector elements, wherein the liquid crystal elements correspond to the detector elements;

an array of focusing lenses disposed adjacent to the array of detector elements, wherein each focusing lens corresponds to at least one detector element; and

means for selecting a liquid crystal element to cause at least one of the corresponding detector elements associated with the liquid crystal element to receive light reflected from the bar code symbol in focus.

14. A bar code reader for reading a bar code symbol according to claim 13, wherein said means for selecting selects based upon a distance between the bar code symbol and the detector elements.

15. The bar code reader according to claim 13, wherein the array of focusing lenses is attached to the array of detector elements.

16. The bar code reader according to claim 13, further comprising an array of miniature mirrors disposed adjacent to the array of liquid crystal elements.

17. The bar code reader according to claim 13, wherein the means for selecting causes the detector elements to receive light such that less than the entire bar code symbol is detected at one time.

18. The bar code reader according to claim 13, wherein the means for selecting causes the detector elements to receive light such that the entire bar code symbol is detected at one time.

19. The bar code reader according to claim 13, further comprising a light source for emitting a light beam onto the bar code symbol.

20. The bar code reader according to claim 13, wherein the array of liquid crystal elements is disposed in a fixed relation with respect to the array of detector elements.

21. The bar code reader according to claim 13, wherein the detector elements are charge coupled devices.

22. A bar code reader for reading a bar code symbol, comprising:

an array of detector elements;

an array of selectable miniature mirror elements optically coupled to the array of detector elements, wherein the miniature mirror elements correspond to the detector elements;

an array of focusing lenses disposed adjacent to the array of detector elements, wherein each focusing lens corresponds to at least one detector element; and

means for selecting a miniature mirror element to cause at least one of the corresponding detector elements associated with the miniature mirror element to receive light reflected from the bar code symbol in focus.

23. A bar code reader for reading a bar code symbol according to claim 22, wherein said means for selecting selects based upon a distance between the symbol and the detector elements.

24. The bar code reader according to claim 22, wherein the array of focusing lenses is attached to the array of detector elements.

25. The bar code reader according to claim 22, wherein the means for selecting causes the detector elements to receive light such that less than the entire bar code symbol is detected at one time.

26. The bar code reader according to claim 22, wherein the means for selecting causes the detector elements to receive light such that the entire bar code symbol is detected at one time.

27. The bar code reader according to claim 22, further comprising a light source for emitting a light beam onto the bar code symbol.

28. The bar code reader according to claim 22, wherein the detector elements are charge coupled devices.

29. A method of reading a bar code symbol, comprising the steps of:

spacing an array of detector elements from an array of selectable optical elements;

disposing an array of focusing lenses adjacent to the detector array, each focusing lens corresponding to at least one detector element;

selectively activating the optical elements, which correspond to the detector elements; and

detecting light reflected from the bar code symbol, via the optical elements, at the corresponding detector elements, wherein the detected light is in focus.

30. The method of reading a bar code symbol according to claim 29, further comprising attaching the array of focusing lenses to the detector array.

31. The method according to claim 29, further comprising the step of emitting a light beam onto the bar code symbol.

32. The method according to claim 29, wherein the step of selectively activating the optical elements comprises the substep of selectively activating the optical elements to detect at one time less than the entire bar code symbol.

33. The method according to claim 29, wherein the step of selectively activating the optical elements comprises the substep of selectively activating the optical elements to detect at one time the entire bar code symbol.

34. The method according to claim 29, wherein the step of selectively activating the optical elements comprises the substep of selectively activating the optical elements such that the bar code symbol is read at a selected focal distance.