APPARATUS FOR AND METHOD OF UNIFORMLY ILLUMINATING FIELDS OF VIEW IN A POINT-OF-TRANSACTION WORKSTATION

• US 20130134220A1
• Filed: 11/29/2011
• Published: 05/30/2013
• Est. Priority Date: 11/29/2011
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: BARKAN, Edward, DRZYMALA, Mark, CHEN, Caihua
• Granted Patent: US 9,016,575 B2
• Time in Patent Office: Days
• US Class Current: 235/455
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• 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 7/1096 the scanner having more than one scanning window, e.g. two substantially orthogonally placed scanning windows for integration into a check-out counter of a super-market

Abstract

Indicia are imaged at a workstation having windows arranged in intersecting planes. The workstation also has solid-state imagers with fields of view that are split into intersecting subfields that look out through the windows, as well as illumination assemblies each having multiple light sources that illuminate each subfield with illumination light over an illumination field that overlaps a respective subfield. Light-modifying elements, such as lenses or baffles that are radially offset from the multiple light sources, condition the illumination light from the multiple light sources to be generally uniform in light intensity over at least one illuminated subfield.

Claims

1. An apparatus for imaging indicia, comprising:

a housing;

a window supported by the housing;

a solid-state imager supported by the housing and having an array of image sensors with a field of view;

an optical system supported by the housing and operative for splitting the field of view of the imager into a plurality of intersecting subfields of view that extend through and past the window to the indicia to be imaged;

a plurality of illumination assemblies, one for each subfield of view, each illumination assembly having a plurality of illumination light sources for illuminating a respective subfield of view with illumination light over an illumination field that overlaps the respective subfield of view, the optical system being further operative for capturing the illumination light returned from the indicia in each illuminated subfield of view;

a controller operatively connected to the imager and the illumination assemblies, for processing the captured illumination light in at least one of the illuminated subfields of view; and

a plurality of light-modifying elements, one for each illumination assembly, each light-modifying element being operative for conditioning the illumination light from the plurality of illumination light sources to be generally uniform in light intensity over the at least one illuminated subfield of view.

2. The apparatus of claim 1, wherein the window is located in one of an upright plane and a generally horizontal plane;

and further comprising an additional window located in the other of the upright plane and the generally horizontal plane, and an additional solid-state imager supported by the housing and having an additional array of sensors with an additional field of view.

3. The apparatus of claim 2, wherein the optical system includes an optical splitter for splitting the field of view of the imager into a set of the subfields of view that pass through the window, and an additional optical splitter for splitting the additional field of view of the additional imager into a set of the subfields of view that pass through the additional window.

4. The apparatus of claim 1, wherein each illumination light source emits an illumination light beam, wherein each illumination assembly has a plurality of the illumination light sources in close adjacent relationship, wherein each light-modifying element includes a plurality of lenses having respective optical axes and at least partly overlying the closely adjacent plurality of the illumination light sources, wherein each illumination light source is offset from a respective lens in a direction radially of a respective optical axis to combine the illumination light beams from the closely adjacent plurality of the illumination light sources into a combined light beam having an intensity that is generally uniform over the at least one illuminated subfield of view.

5. The apparatus of claim 1, wherein each illumination light source emits an illumination light beam, wherein each illumination assembly has a plurality of the illumination light sources in close adjacent relationship, wherein each light-modifying element includes a plurality of lenses having respective optical axes and overlying the closely adjacent plurality of the illumination light sources, and a plurality of baffles at least partly overlying the closely adjacent pluralities of the illumination light sources and the lenses, wherein each baffle is offset from a respective illumination light source and a respective lens in a direction radially of a respective optical axis to combine the illumination light beams from the closely adjacent plurality of the illumination light sources into a combined light beam having an intensity that is generally uniform over the at least one illuminated subfield of view.

6. The apparatus of claim 1, wherein the illumination light sources of each illumination assembly are light emitting diodes (LEDs) arranged in a row and commonly mounted on a printed circuit board.

7. A point-of-transaction workstation for processing products by electro-optically imaging indicia associated with the products, comprising:

a housing having one window located in an upright plane, and another window located in a generally horizontal plane that intersects the upright plane, the windows bounding an area in which each product is presented for processing;

a pair of solid-state imagers, one for each window, supported by the housing, the imagers having respective arrays of image sensors with intersecting fields of view that extend through and past the windows to the indicia to be imaged;

a plurality of illumination assemblies, one for each field of view, each illumination assembly having a plurality of illumination light sources for illuminating a respective field of view with illumination light over an illumination field that overlaps the respective field of view, the optical system being further operative for capturing the illumination light returned from the indicia in each illuminated field of view;

a controller operatively connected to the imager and the illumination assemblies, for processing the captured illumination light in at least one of the illuminated fields of view; and

a plurality of light-modifying elements, one for each illumination assembly, each light-modifying element being operative for conditioning the illumination light from the plurality of illumination light sources to be generally uniform in light intensity over the at least one illuminated field of view.

8. The workstation of claim 7, and an optical system supported by the housing and operative for splitting the field of view of each imager into a plurality of intersecting subfields of view that extend through and past the windows to the indicia to be imaged;

9. The workstation of claim 8, wherein the optical system includes a pair of optical splitters, each for splitting the field of view of a respective imager into a set of the subfields of view that pass through a respective window.

10. The workstation of claim 8, wherein each illumination light source emits an illumination light beam, wherein each illumination assembly has a plurality of the illumination light sources in close adjacent relationship, wherein each light-modifying element includes a plurality of lenses having respective optical axes at least partly overlying the closely adjacent plurality of the illumination light sources, wherein each illumination light source is offset from a respective lens in a direction radially of a respective optical axis to combine the illumination light beams from the closely adjacent plurality of the illumination light sources into a combined light beam having an intensity that is generally uniform over the at least one illuminated subfield of view.

11. The workstation of claim 8, wherein each illumination light source emits an illumination light beam, wherein each illumination assembly has a plurality of the illumination light sources in close adjacent relationship, wherein each light-modifying element includes a plurality of lenses having respective optical axes and overlying the closely adjacent plurality of the illumination light sources, and a plurality of baffles at least partly overlying the closely adjacent pluralities of the illumination light sources and the lenses, wherein each baffle is offset from a respective illumination light source and a respective lens in a direction radially of a respective optical axis to combine the illumination light beams from the closely adjacent plurality of the illumination light sources into a combined light beam having an intensity that is generally uniform over the at least one illuminated subfield of view.

12. The workstation of claim 7, wherein the illumination light sources of each illumination assembly are light emitting diodes (LEDs) arranged in a row and commonly mounted on a printed circuit board.

13. A method of imaging indicia, comprising:

supporting a window on a housing;

configuring a solid-state imager having an array of image sensors with a field of view that looks through the window;

splitting the field of view of the imager into a plurality of intersecting subfields of view that extend through and past the window to the indicia to be imaged;

illuminating the subfields of view with a plurality of illumination assemblies, one for each subfield of view, each illumination assembly having a plurality of illumination light sources for illuminating a respective subfield of view with illumination light over an illumination field that overlaps the respective subfield of view;

capturing the illumination light returned from the indicia in each illuminated subfield of view;

processing the captured illumination light in at least one of the illuminated subfields of view; and

conditioning the illumination light from the plurality of illumination light sources to be generally uniform in light intensity over the at least one illuminated subfield of view.

14. The method of claim 13, and locating the window in one of an upright plane and a generally horizontal plane;

and locating an additional window in the other of the upright plane and the generally horizontal plane, and configuring an additional solid-state imager having an additional array of sensors with an additional field of view.

15. The method of claim 14, wherein the splitting is performed by splitting a respective field of view of a respective imager into a set of the subfields of view that pass through a respective window.

16. The method of claim 13, wherein the illuminating is performed by energizing each illumination light source to emit an illumination light beam, and by arranging a plurality of the illumination light sources of each illumination assembly in close adjacent relationship;

and wherein the conditioning is performed by at least partly overlying the closely adjacent plurality of the illumination light sources with a plurality of lenses having respective optical axes, and by offsetting each illumination light source from a respective lens in a direction radially of a respective optical axis to combine the illumination light beams from the closely adjacent plurality of the illumination light sources into a combined light beam having an intensity that is generally uniform over the at least one illuminated subfield of view.

17. The method of claim 13, wherein the illuminating is performed by energizing each illumination light source to emit an illumination light beam, and by arranging a plurality of the illumination light sources of each illumination assembly in close adjacent relationship;

and wherein the conditioning is performed by overlying the closely adjacent plurality of the illumination light sources with a plurality of lenses having respective optical axes, and by at least partly overlying the closely adjacent pluralities of the illumination light sources and the lenses with a plurality of baffles, and by offsetting each baffle from a respective illumination light source and a respective lens in a direction radially of a respective optical axis to combine the illumination light beams from the closely adjacent plurality of the illumination light sources into a combined light beam having an intensity that is generally uniform over the at least one illuminated subfield of view.

18. The method of claim 13, and configuring the illumination light sources of each illumination assembly as light emitting diodes (LEDs), and by arranging and commonly mounting the LEDs in a row on a printed circuit board.