Diffuse bright field illumination system for a barcode reader

• US 9,430,687 B2
• Filed: 10/14/2015
• Issued: 08/30/2016
• Est. Priority Date: 10/24/2013
• Status: Active Grant

• Current Assignee: The Code Corporation (Brady Corporation)
• Original Assignee: The Code Corporation (Brady Corporation)
• Inventors: Lei, Ming, Powell, George
• Primary Examiner(s): LEE, SEUNG H
• Application Number:
  US14/883,103
• Publication Number:
  US 20160034735A1
• Time in Patent Office: 321 Days
• Field of Search: 235/439, 235/462.06, 235/462.42, 23547201-47203
• US Class Current: 1/1
• CPC Class Codes: G06K 19/06028 using bar codes
• CPC Class Codes: G06K 7/10732 Light sources
• 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: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• CPC Class Codes: G06K 7/1413 1D bar codes

Abstract

One aspect of the present disclosure is related to a barcode reader that includes a bright field illumination system, a dark field illumination system, and an additional illumination system that is better able to illuminate an area of the reader'"'"'s field of view between the far zone (where bright field illumination is optimal) and the close zone (where dark field illumination is optimal). In this “center zone,” the dark field illumination may not be bright enough and the bright field illumination may not be diffuse enough for reading a barcode.

Claims

1. A barcode reader with three distinct illumination systems, comprising:

a bright field illumination system that directs bright field illumination into a field of view of the barcode reader substantially parallel to an optical axis of the barcode reader, wherein the bright field illumination is optimal for barcode reading within a far zone of the field of view;

a dark field illumination system that directs dark field illumination into the field of view at a non-zero angle relative to a plane that is perpendicular to the optical axis, wherein the dark field illumination is optimal for barcode reading within a close zone of the field of view, the close zone of the field of view being closer to the reader than the far zone of the field of view and separated from the far zone of the field of view by at least a portion of a center zone; and

a diffuse bright field illumination system that directs diffuse bright field illumination into the field of view substantially parallel to the optical axis, wherein the diffuse bright field illumination is diffused with an intensity distribution of illumination within the center zone of the field of view that is more even than the intensity distribution of illumination from the bright field illumination system.

2. The barcode reader of claim 1, wherein the bright field illumination is not diffused with a sufficiently even intensity for evenly illuminating a barcode within at least part of the center zone, and the dark field illumination is not sufficiently bright to provide sufficient illumination for reading a barcode reading within at least part of the center zone.

3. The barcode reader of claim 1, wherein the center zone overlaps with at least a portion of the far zone and overlaps with at least a portion of the close zone.

4. The barcode reader of claim 1, wherein:

the bright field illumination system comprises a first plurality of illumination elements;

the dark field illumination system comprises a second plurality of illumination elements;

the diffuse bright field illumination system comprises a third plurality of illumination elements; and

the first plurality of illumination elements, the second plurality of illumination elements, and the third plurality of illumination elements are actuated independent of each other.

5. The barcode reader of claim 4, wherein:

the diffuse bright field illumination system comprises an optical substrate with an aperture about the optical axis through which a camera of the barcode reader captures an image of the field of view, the optical substrate comprising light-diffusing characteristics, wherein a front major surface and a back major surface of the optic are located in a plane that is substantially perpendicular to the optical axis; and

the third plurality of illumination elements is located on edges of the optic, and the optical substrate comprises one or more diffusion features configured to diffuse illumination generated by the third plurality of illumination elements into the field of view.

6. The barcode reader of claim 5, wherein a shape of at least one of the front major surface and the back major surface is one of at least planar, concave, and convex.

7. The barcode reader of claim 4, wherein:

the diffuse bright field illumination system comprises an optical substrate comprising light-diffusing characteristics, wherein a front major surface and a back major surface of the optic are located in a plane that is substantially perpendicular to the optical axis; and

the third plurality of illumination elements is located on edges of the optic, and the optical substrate comprises one or more diffusion features positioned around the optical axis and not within the field of view of a camera of the barcode reader, and configured to diffuse illumination generated by the third plurality of illumination elements into the field of view.

8. The barcode reader of claim 7, wherein a shape of at least one of the front major surface and the back major surface is one of at least planar, concave, and convex.

9. A barcode reader with three distinct illumination systems, comprising:

a bright field illumination system that includes first illumination elements projecting illumination, through first illumination optics, into a field of view of the barcode reader substantially parallel to an optical axis of the barcode reader, the first illumination optics refracting the illumination generated by the first illuminating elements;

a dark field illumination system that includes second illumination elements projecting dark field illumination, through second illumination optics, into the field of view at a non-zero angle relative to a plane that is perpendicular to the optical axis; and

a diffuse bright field illumination system that includes third illumination elements projecting illumination, through third illumination optics, into the field of view of the barcode reader substantially parallel to the optical axis, the third illumination optics diffusing illumination generated by the third illumination elements by total internal reflection between at least two major surfaces of the third illumination optic.

10. The barcode reader of claim 9, wherein the first plurality of illumination elements, the second plurality of illumination elements, and the third plurality of illumination elements are actuated independent of each other.

11. The barcode reader of claim 10, wherein:

the third illumination optics comprise an optical substrate with an aperture about the optical axis through which a camera of the barcode reader captures an image of the field of view, the optical substrate comprising light-diffusing characteristics, wherein a front major surface and a back major surface of the optic are located in a plane that is substantially perpendicular to the optical axis; and

the third plurality of illumination elements is located on edges of the optic, and the optical substrate comprises one or more diffusion features configured to diffuse illumination generated by the third plurality of illumination elements into the field of view.

12. The barcode reader of claim 11, wherein a shape of at least one of the front major surface and the back major surface is one of at least planar, concave, and convex.

13. The barcode reader of claim 9, wherein:

the third illumination optics comprise an optical substrate comprising light-diffusing characteristics, wherein a front major surface and a back major surface of the optic are located in a plane that is substantially perpendicular to the optical axis; and

the third plurality of illumination elements is located on edges of the optic, and the optical substrate comprises one or more diffusion features, positioned around the optical axis and not within the field of view of a camera of the barcode reader, and configured to diffuse illumination generated by the third plurality of illumination elements into the field of view.

14. The barcode reader of claim 13, wherein a shape of at least one of the front major surface and the back major surface is one of at least planar, concave, and convex.

15. A method of operating a barcode reader with three distinct illumination systems, the method comprising:

illuminating the barcode within a field of view of a camera using a bright field illumination system if the barcode is within a far zone of the field of view, wherein;

the bright field illumination system comprises first illumination elements projecting illumination, through first illumination optics, into a field of view of the barcode reader substantially parallel to an optical axis of the barcode reader; and

the first illumination optics refract the illumination generated by the first illuminating elements;

illuminating the barcode within the field of view of the camera using a dark field illumination system if the barcode is within a close zone of the field of view, the dark field illumination system comprising second illumination elements projecting dark field illumination, through second illumination optics, into the field of view at a non-zero angle relative to a plane that is perpendicular to the optical axis; and

illuminating the barcode within the field of view of the camera using a diffuse bright field illumination system if the barcode is within the center zone, the diffuse bright field illumination system comprising third illumination elements projecting illumination, through third illumination optics, into the field of view of the barcode reader substantially parallel to the optical axis;

wherein the close zone of the field of view is closer to the reader than the far zone of the field of view and is separated from the far zone of the field of view by at least a portion of a center zone.

16. The method of claim 15, wherein the first illumination elements, the second illumination elements, and the third illumination elements are actuated independent of each other.

17. The method of claim 16, wherein:

the third illumination optics comprise an optical substrate with an aperture about the optical axis through which the camera of the barcode reader captures an image of the field of view, the optical substrate comprising light-diffusing characteristics, wherein a front major surface and a back major surface of the optic are located in a plane that is substantially perpendicular to the optical axis; and

the second plurality of illumination elements is located on edges of the optic, and the optical substrate comprises one or more diffusion features configured to diffuse illumination generated by the second plurality of illumination elements into the field of view.

18. The method of claim 17, wherein a shape of at least one of the front major surface and the back major surface is one of at least planar, concave, and convex.

19. The method of claim 16, wherein:

the third illumination optics comprise an optical substrate comprising light-diffusing characteristics, wherein a front major surface and a back major surface of the optic are located in a plane that is substantially perpendicular to the optical axis; and

the second plurality of illumination elements is located on edges of the optic, and the optical substrate comprises one or more diffusion features, positioned around the optical axis and not within the field of view of the camera of the barcode reader, and configured to diffuse illumination generated by the second plurality of illumination elements into the field of view.

20. The method of claim 19, wherein a shape of at least one of the front major surface and the back major surface is one of at least planar, concave, and convex.