MONOLITHIC MIRROR STRUCTURE FOR USE IN A MULTI-PERSPECTIVE OPTICAL CODE READER

• US 20100163622A1
• Filed: 12/23/2009
• Published: 07/01/2010
• Est. Priority Date: 02/12/2008
• Status: Active Grant

• Current Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Original Assignee: Datalogic Scanning Incorporated (Datalogic S.p.A.)
• Inventors: Olmstead, Bryan L.
• Granted Patent: US 8,608,076 B2
• Time in Patent Office: Days
• US Class Current: 235/454
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10861 sensing of data fields affixed to objects or articles, e.g. coded labels postal sorting B07C3/14, conveying articles B65G47/48

Abstract

A monolithic compound mirror structure is used in an optical code reader employing an imager that captures images of items bearing optical codes in a viewing volume of the optical code reader. The monolithic compound mirror structure comprises a plurality of highly reflective surfaces positioned on the structure so that the structure can be positioned in a field of view of the imager in the optical code reader and oriented so that two or more of the plurality of highly reflective surfaces appear in the field of view of the imager, to thereby split the field of view of the imager into two or more different views into the viewing volume. The different views into the viewing volume may be direct off of the monolithic compound mirror structure or indirect off of one or more intermediate mirrors.

Claims

1. A monolithic compound minor structure for use in an optical code reader employing an imager that captures images of items bearing optical codes in a viewing volume of the optical code reader, the compound monolithic mirror structure comprising a plurality of highly reflective surfaces positioned on the structure so that the structure can be positioned in a field of view of the imager in the optical code reader and oriented so that two or more of the plurality of highly reflective surfaces appear in the field of view of the imager, to thereby split the field of view of the imager into two or more different views into the viewing volume.

2. A monolithic compound mirror structure according to claim 1, wherein the monolithic mirror structure comprises a core piece and a plurality of highly reflective plates attached to the core to form the plurality of highly reflective surfaces.

3. A monolithic compound mirror structure according to claim 2, wherein the core piece is molded.

4. A monolithic compound mirror structure according to claim 2, wherein the core piece is either machined, drawn, extruded or cast.

5. A monolithic compound mirror structure according to claim 2, wherein the highly reflective plates are attached to the core piece by an adhesive.

6. A monolithic compound minor structure according to claim 2, wherein the highly reflective plates are formed of metal-coated glass.

7. A monolithic compound mirror structure according to claim 1, wherein the highly reflective surfaces are substantially planar.

8. A monolithic compound mirror structure according to claim 1, wherein the structure comprises one or more surfaces, other than the plurality of highly reflective surfaces, that are highly nonreflective.

9. A monolithic compound mirror structure according to claim 1, wherein at least some of the highly reflective surfaces constitute a Fresnel prism.

10. A monolithic compound mirror structure according to claim 8, wherein part of the structure between highly reflective surfaces are highly nonreflective.

11. A monolithic compound mirror structure according to claim 1, wherein the number of highly reflective surfaces and the number of different views into the viewing volume are the same and are at least three.

12. A monolithic compound mirror structure according to claim 1, wherein each of the highly reflective surfaces on the compound mirror structure define a normal vector, and the set of all normal vectors so defined point into different directions in a common hemisphere.

13. A monolithic compound mirror structure according to claim 1, wherein the structure comprises plastic.

14. A monolithic compound mirror structure according to claim 13, wherein the structure comprises at least one reflective metal coating.

15. An monolithic compound mirror structure according to claim 1, wherein the plurality of highly reflective surfaces on the monolithic compound mirror structure are strip-shaped and have respective lengthwise major axes, which are non-intersecting.

16. An optical code reader comprising:

an imager that captures images of items bearing optical codes in a viewing volume of the optical code reader, the imager having a field of view; and

a monolithic compound mirror structure comprising a plurality of highly reflective surfaces on the structure, the structure positioned in the optical code reader in a field of view of the imager and oriented so that two or more of the plurality of highly reflective surfaces appear in the field of view of the imager, to thereby split the field of view of the imager into two or more different views into the viewing volume.

17. An optical code reader according to claim 16, further comprising:

an intermediate mirror positioned to reflect light from the viewing volume onto one or more of the plurality of highly reflective surfaces on the monolithic compound mirror structure.

21. An optical code reader according to claim 16, further comprising:

an first alignment feature on the monolithic mirror structure; and

a second alignment feature on the optical code reader, the second alignment feature being positioned, shaped and oriented to mate with the first alignment feature on the monolithic compound mirror structure when the monolithic compound mirror structure is in a desired position and orientation in the optical code reader.

22. An optical code reader according to claim 16, wherein the monolithic compound mirror structure is integral to at least part of the optical code reader.

23. An optical code reader according to claim 16, further comprising:

an illumination source that shines light into the viewing volume,

wherein the light from the illumination source reflects off the one or more of the plurality of highly reflective surfaces on the monolithic compound mirror structure to reach the viewing volume.

24. An optical code reader according to claim 16, wherein the imager is a CMOS imager.

25. An optical code reader according to claim 16, wherein at least two of the different views into the viewing volume have optical path axes that differ by at least approximately 15 degrees.

26. An optical code reader according to claim 16, wherein at least two of the different views into the viewing volume have optical path axes that differ by at least approximately 30 degrees.

27. An optical code reader according to claim 16, wherein at least two of the different views into the viewing volume have optical path axes that differ by at least approximately 45 degrees.

28. An optical code reader according to claim 16, wherein at least two of the different views into the viewing volume have optical path axes that differ by at least approximately 60 degrees.

29. An optical code reader according to claim 16, wherein at one of the different views into the viewing volume has a field of view having a substantial nonoverlapping region with respect to other views in the viewing volume.

30. An optical code reader according to claim 16, wherein the optical code reader is a bioptic reader that captures at least one lower perspective and at least one upper perspective into the viewing volume.

31. An optical code reader according to claim 30, wherein the plurality of highly reflective surfaces on the monolithic compound mirror structure comprise:

a first highly reflective surface disposed in an image path for a view having a lower back perspective into the viewing volume;

a second highly reflective surface disposed in an image path for a view having a lower left perspective into the viewing volume; and

a third highly reflective surface disposed in an image path for a view having a lower right perspective into the viewing volume.

32. An optical code reader according to claim 30, wherein the plurality of highly reflective surfaces on the monolithic compound mirror structure comprise:

a first highly reflective surface disposed in an image path for a view having an upper perspective into the viewing volume;

a second highly reflective surface disposed in an image path for a view having a lower left perspective into the viewing volume; and

a third highly reflective surface disposed in an image path for a view having a lower right perspective into the viewing volume.

33. An optical code reader according to claim 30, wherein the plurality of highly reflective surfaces on the monolithic compound mirror structure comprise:

a first highly reflective surface disposed in an image path for a view having an upper perspective into the viewing volume;

a second highly reflective surface disposed in an image path for a view having a lower left perspective into the viewing volume; and

a third highly reflective surface disposed in an image path for a view having a lower right perspective into the viewing volume; and

a fourth highly reflective surface disposed in an image path for a view having a lower back perspective into the viewing volume.

34. An optical code reader according to claim 16, wherein the optical code reader is a tunnel reader.

35. An optical code reader according to claim 34, wherein the plurality of highly reflective surfaces on the monolithic compound mirror structure comprise:

a first set of highly reflective surfaces disposed in one or more image paths for one or more corresponding views into the viewing volume from one or more leading perspectives; and

a second set of highly reflective surfaces disposed in one or more image paths for one or more corresponding views into the viewing volume from one or more trailing perspectives.

18. An optical code reader according to claim 18, further comprising:

a second intermediate mirror positioned to reflect light from the viewing volume onto one or more of the plurality of highly reflective surfaces on the monolithic compound mirror structure.

19. An optical code reader according to claim 18, wherein the first and second intermediate mirrors are in the same optical path.

20. An optical code reader according to claim 18, wherein the first and second intermediate mirrors are in the different optical paths.