Optimizing Optical Quality of a Sensor in a Bar Code Reader

• US 20090159685A1
• Filed: 12/20/2007
• Published: 06/25/2009
• Est. Priority Date: 12/20/2007
• Status: Abandoned Application

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Liu, Rong, Yu, Ming, Shi, Tsi David
• Application Number:
  US11/961,338
• Publication Number:
  US 20090159685A1
• Time in Patent Office: Days
• US Class Current: 235/462.420
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners

Abstract

An exemplary barcode reader includes an imaging system that includes a light monitoring pixel array for converting light reflected from a target into electrical signals, and an optical system having one or more focusing lenses positioned with respect to the pixel array to transmit an image of a target object toward said pixel array. An illumination system comprising a light source for illuminating a the target within a field of view defined by the optical system. A filter is disposed adjacent the focusing lens and passing illumination with a wavelength less than about 700 nanometers to the pixel array and impedes the passage of light having a wavelength greater than this value.

Claims

1. A barcode reader for imaging a target comprising:

an imaging system that includes a light monitoring pixel array for converting light reflected from a target into electrical signals;

an optical system having a plurality of focusing lenses positioned with respect to the pixel array to transmit an image of the target toward said pixel array;

an illumination system comprising a light source for illuminating the target within a field of view defined by the optical system;

a thin film filter deposited onto a surface of one focusing lens of said plurality of focusing lenses, said one focusing lens located closest to the pixel array for passing visible light below a predetermined wavelength range to the pixel array and impeding the passage of infrared light above the predetermined wavelength range.

3. The apparatus of claim 1 wherein the thin filter impedes infrared light having a wavelength above 700 nanometers.

6. The apparatus of claim 1 wherein the thin film filter is deposited on a surface of the focusing lens facing the pixel array.

8. The apparatus of claim 1 wherein the lens closest the pixel array includes a generally planar surface to which the thin film filter is applied.

2. (canceled)

4-5. -5. (canceled)

7. (canceled)

9. A bar code reader comprising:

an illumination system for generating illumination directed at a target bar code;

an imaging system including a pixel array, and a plurality of focusing lenses for focusing an image of the target bar code onto the pixel array; and

a thin film filter deposited onto a surface of one focusing lens of the plurality of said lenses, said one focusing lens positioned closest to the pixel array that passes light within a visible range to the pixel array and impedes the passage of infrared light having a wavelength above the visible range.

11. The bar code reader of claim 9 wherein the filter impedes light having a wavelength above 700 nanometers.

15. The barcode reader of claim 9 wherein the thin film filter is deposited on a lens facing the pixel array.

10. (canceled)

12-14. -14. (canceled)

16. A method for imaging a target comprising:

positioning a light monitoring pixel array within a housing for converting light reflected from a target into electrical signals;

providing a plurality of focusing lenses with respect to the pixel array to transmit an image of the target toward said pixel array;

illuminating a the target within a field of view defined by the one or more focusing lenses;

depositing a thin film filter onto a focusing lens closest to the pixel array to impede the passage of infrared light having a wavelength above a visible range from reaching the light monitoring pixel array; and

evaluating an output from the pixel array to determine a characteristic of the target.

18. The method of claim 16 wherein infrared light having a wavelength greater than about 700 nanometers is impeded from reaching the pixel array due to said thin film filter.

17. (canceled)

19-20. -20. (canceled)