Retro-reflective scanner having exit window with positive optical power

• US 20060266839A1
• Filed: 05/31/2005
• Published: 11/30/2006
• Est. Priority Date: 05/31/2005
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Yavid, Dmitriy, Gurevich, Vladimir
• Granted Patent: US 7,204,424 B2
• Time in Patent Office: Days
• US Class Current: 235/462.450
• CPC Class Codes: G06K 7/10683 Arrangement of fixed elements
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B

Abstract

A portable electo-optical scanner for reading a target bar code having a plurality of bar code elements. The portable scanner includes: a housing supporting a scanning module and an exit window. The scanning module scans the target bar code with a scanning beam and collecting reflected light returning from the bar code. The scanning module includes: a beam source emitting a scanning beam; photodetector circuitry; and a retro-reflective oscillating mirror including a light collection mirror and an integral scanning or beam directing mirror. The scanning mirror is positioned to intersect the scanning beam and direct the scanning beam through the exit window. Oscillation of the oscillating mirror causes the scanning beam to be repetitively scanned along a scanning direction across the target bar code. The light collection mirror has a field of view that follows the scanning beam. The light collection mirror receives reflected light from the target bar code and directs the reflected light toward the photodetector circuitry. The exit window comprises a lens having a positive optical power with respect to the scanning direction.

Claims

1. A portable electo-optical scanner for reading a target bar code having a plurality of bar code elements, the portable scanner comprising:

a) a housing supporting a scanning module and an exit window;

b) the scanning module for scanning the target bar code with a scanning beam and collecting reflected light returning from the bar code, the scanning beam and the reflected light passing through the exit window, the scanning module including;

1) a beam source emitting a scanning beam;

2) beam directing apparatus causing the scanning beam to be repetitively scanned along a scanning direction across the target bar code;

3) photodetector circuitry; and

4) the light collection mirror having a field of view that follows the scanning beam as it moves along the scanning direction, the light collection mirror receiving reflected light from the target bar code and directing the reflected light toward the photodetector circuitry and wherein at least a portion of the exit window comprises a lens having a positive optical power with respect to the scanning direction.

2. The portable electro-optical scanner of claim 1 wherein the light collection mirror is an oscillating mirror that includes an integral beam directing mirror, the beam directing mirror positioned to intersect the scanning beam and direct the scanning beam through the exit window, oscillation of the oscillating mirror pivots the beam directing mirror causing the scanning beam to be repetitively scanned along a scanning direction across the target bar code.

3. The portable electo-optical scanner of claim 1 wherein the exit window comprises a lens having a positive optical power in all directions.

4. The portable electro-optical scanner of claim 1 wherein the exit window lens has a convex surface on an outward side of the exit window facing the target bar code and a convex surface on an inward side of the exit window facing the scanning module.

5. The portable electro-optical scanner of claim 1 wherein the exit window lens has a convex surface on an outward side of the exit window facing the target bar code and a flat surface on an inward side of the exit window facing the scanning module.

6. The portable electro-optical scanner of claim 1 wherein the exit window lens has a convex surface on an outward side of the exit window facing the target bar code and a concave surface on an inward side of the exit window facing the scanning module.

7. The portable electro-optical scanner of claim 2 wherein the beam direction mirror protrudes outwardly from a central portion of the light collecting mirror.

8. The portable electro-optical scanner of claim 2 wherein the oscillating mirror is fabricated of a single piece of plastic.

9. A scanning module for use in a electro-optical scanner for scanning a target bar code with a scanning beam and collecting reflected light returning from the bar code, the scanning beam, the scanning module comprising:

1) a beam source emitting a scanning beam;

2) an exit window;

3) a beam directing apparatus causing the scanning beam to be directed through the exit window and repetitively scanned along a scanning direction across the target bar code;

4) photodetector circuitry; and

5) the light collection mirror having a field of view that follows the scanning beam as it moves along the scanning direction, the light collection mirror receiving reflected light from the target bar code and directing the reflected light toward the photodetector circuitry and wherein at least a portion of the exit window comprises a lens having a positive optical power with respect to the scanning direction.

10. The scanning module of claim 9 wherein the light collection mirror is an oscillating mirror that includes an integral beam directing mirror, the beam directing mirror positioned to intersect the scanning beam and direct the scanning beam through the exit window, oscillation of the oscillating mirror pivots the beam directing mirror causing the scanning beam to be repetitively scanned along a scanning direction across the target bar code.

11. The scanning module of claim 9 wherein the exit window comprises a lens having a positive optical power in all directions.

12. The scanning module of claim 9 wherein the exit window lens has a convex surface on an outward side of the exit window facing the target bar code and a convex surface on an inward side of the exit window facing the scanning module.

13. The scanning module of claim 9 wherein the exit window lens has a convex surface on an outward side of the exit window facing the target bar code and a flat surface on an inward side of the exit window facing the scanning module.

14. The scanning module of claim 9 wherein the exit window lens has a convex surface on an outward side of the exit window facing the target bar code and a concave surface on an inward side of the exit window facing the scanning module.

15. The scanning module of claim 10 wherein the beam direction mirror protrudes outwardly from a central portion of the light collecting mirror.

16. The scanning module of claim 10 wherein the oscillating mirror is fabricated of a single piece of plastic.