Imaging reader with asymmetrical magnification

• US 8,777,105 B2
• Filed: 10/21/2009
• Issued: 07/15/2014
• Est. Priority Date: 10/21/2009
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Vinogradov, Igor, Zhang, Heng, Veksland, Michael
• Primary Examiner(s): Le, Thien M
• Assistant Examiner(s): TAYLOR, APRIL ALICIA
• Application Number:
  US12/582,954
• Publication Number:
  US 20110089240A1
• Time in Patent Office: 1,728 Days
• Field of Search: 235/454, 235/462.01, 235/462.14, 235/462.25, 235/462.32, 235/462.43
• US Class Current: 235/454
• CPC Class Codes: G02B 13/08 Anamorphotic objectives
• CPC Class Codes: G02B 13/16 for use in conjunction with image converters or intensifiers , or for use with projectors, e.g. objectives for projection TV
• CPC Class Codes: G02B 13/22 Telecentric objectives or lens systems
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B

Abstract

A solid-state imager is mounted in a reader, such as a bi-optical, dual window, point-of-transaction workstation, for capturing light along an optical axis over a field of view from coded indicia. An optical assembly including non-rotationally symmetrical optics is operative for optically modifying and asymmetrically magnifying an image of the indicia and the field of view of the imager along mutually orthogonal directions generally perpendicular to the optical axis, and for increasing resolution of the imager along one of the directions. Preferably, the non-rotationally symmetrical optics includes a cylindrical lens having an aspherical profile along the one direction, and a planar profile along the other of the directions.

Claims

1. A reader for electro-optically reading indicia, comprising:

a housing;

a solid-state imager within the housing, for capturing light along an optical axis from the indicia over a field of view;

a controller for controlling the imager to produce an electrical signal indicative of the indicia being read, and for processing the electrical signal to read the indicia;

an optical assembly including non-rotationally symmetrical optics for optically modifying and asymmetrically magnifying an image of the indicia and the field of view of the imager along mutually orthogonal directions generally perpendicular to the optical axis, and for increasing resolution of the imager along one of said directions;

wherein the optical assembly includes rotationally symmetrical optics, together operative with the non-rotationally symmetrical optics, for projecting the light from the indicia onto the imager; and

wherein the non-rotationally symmetrical optics has only one non-rotationally symmetrical optics lens positioned between the rotationally symmetrical optics and the solid-state imager, the non-rotationally symmetrical optics lens has a first surface facing the rotationally symmetrical optics and has a second surface facing the solid-state imager, with the first surface having a positive power in one of the mutually orthogonal directions and having substantially no power in the other one of the mutually orthogonal directions, and with the second surface having a negative power in said one of the mutually orthogonal directions and having substantially no power in said other one of the mutually orthogonal directions.

2. The reader of claim 1, wherein the housing has one window located in a generally horizontal plane, and another window located in a generally upright plane that intersects the generally horizontal plane, and wherein the imager captures the light from the indicia through at least one of the windows.

3. The reader of claim 2, and another solid-state imager within the housing, for capturing light along another optical axis from the indicia over another field of view through another of the windows;

and wherein the optical axes intersect, and the fields of view intersect.

4. The reader of claim 3, wherein each imager has pixels lying in respective imager planes generally orthogonal to the respective optical axes, and wherein at least one of the imager planes is oriented at an acute angle with respect to the indicia.

5. The reader of claim 1, wherein the rotationally symmetrical optics includes a Cooke triplet of lenses, an aperture stop, and a lens to make the Cooke triplet telecentric.

6. The reader of claim 1, wherein the non-rotationally symmetrical optics includes one of a cylindrical lens and a toroidal lens having an aspherical profile along said one direction, and a planar profile along the other of said directions.

7. The reader of claim 6, wherein the lens is made of a material that filters visible light in a predetermined frequency range and corrects the lens for chromatic aberration of visible light in a different frequency range.

8. The reader of claim 1, wherein the optical assembly includes a dielectric filter that filters visible light in a predetermined frequency range and corrects the optical assembly for chromatic aberration of visible light in a different frequency range.

9. The reader of claim 1, and a lens holder for holding the optical assembly, and an alignment key on one of the holder and the non-rotationally symmetrical optics for mutual optical alignment.

10. An arrangement for use in electro-optically reading indicia, comprising:

a solid-state imager for capturing light along an optical axis from the indicia over a field of view;

a controller for controlling the imager to produce an electrical signal indicative of the indicia being read, and for processing the electrical signal to read the indicia;

an optical assembly including non-rotationally symmetrical optics for optically modifying and asymmetrically magnifying an image of the indicia and the field of view of the imager along mutually orthogonal directions generally perpendicular to the optical axis, and for increasing resolution of the imager along one of said directions;

wherein the optical assembly includes rotationally symmetrical optics, together operative with the non-rotationally symmetrical optics, for projecting the light from the indicia onto the imager; and

wherein the non-rotationally symmetrical optics has only one non-rotationally symmetrical optics lens positioned between the rotationally symmetrical optics and the solid-state imager, the non-rotationally symmetrical optics lens has a first surface facing the rotationally symmetrical optics and has a second surface facing the solid-state imager, with the first surface having a positive power in one of the mutually orthogonal directions and having substantially no power in the other one of the mutually orthogonal directions, and with the second surface having a negative power in said one of the mutually orthogonal directions and having substantially no power in said other one of the mutually orthogonal directions.

11. The arrangement of claim 10, wherein the non-rotationally symmetrical optics includes one of a cylindrical lens and a toroidal lens having an aspherical profile along said one direction, and a planar profile along the other of said directions.

12. A method of electro-optically reading indicia, comprising the steps of:

capturing light from the indicia with a solid-state imager along an optical axis over a field of view;

controlling the imager to produce an electrical signal indicative of the indicia being read, and processing the electrical signal to read the indicia;

optically modifying and asymmetrically magnifying an image of the indicia and the field of view of the imager along mutually orthogonal directions generally perpendicular to the optical axis, and increasing resolution of the imager along one of said directions, with non-rotationally symmetrical optics;

projecting the light from the indicia onto the imager by employing rotationally symmetrical optics together with the non-rotationally symmetrical optics; and

wherein the non-rotationally symmetrical optics has only one non-rotationally symmetrical optics lens positioned between the rotationally symmetrical optics and the solid-state imager, the non-rotationally symmetrical optics lens has a first surface facing the rotationally symmetrical optics and has a second surface facing the solid-state imager, with the first surface having a positive power in one of the mutually orthogonal directions and having substantially no power in the other one of the mutually orthogonal directions, and with the second surface having a negative power in said one of the mutually orthogonal directions and having substantially no power in said other one of the mutually orthogonal directions.

13. The method of claim 12, and configuring a housing with one window located in a generally horizontal plane, and another window located in a generally upright plane that intersects the generally horizontal plane, and wherein the capturing step is performed by capturing the light from the indicia through at least one of the windows.

14. The method of claim 12, and configuring the rotationally symmetrical optics with a Cooke triplet of lenses, an aperture stop and a lens to make the Cooke triplet telecentric.

15. The method of claim 12, and configuring the non-rotationally symmetrical optics with one of a cylindrical lens and a toroidal lens having an aspherical profile along said one direction, and a planar profile along the other of said directions.

16. The method of claim 15, and making the lens of a material that filters visible light in a predetermined frequency range and corrects the lens for chromatic aberration of visible light in a different frequency range.

17. The method of claim 12, wherein the optically modifying step is performed by including a dielectric filter that filters visible light in a predetermined frequency range and corrects for chromatic aberration of visible light in a different frequency range.

18. The method of claim 12, and aligning the non-rotationally symmetrical optics with a holder for mutual optical alignment.