Instant portable bar code reader

• US 4,894,523 A
• Filed: 04/18/1989
• Issued: 01/16/1990
• Est. Priority Date: 12/28/1981
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Norand Corporation (Baker Hughes Company)
• Inventors: Laser, Vadim, Chadima, George E. Jr.
• Primary Examiner(s): Pitts, Harold I.
• Application Number:
  US07/339,953
• Time in Patent Office: 273 Days
• Field of Search: 235/472, 235/455, 235/462
• US Class Current: 235/462.45
• CPC Class Codes: G06K 7/10594 Beam path
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10772 Moved readers, e.g. pen, wand
• CPC Class Codes: G06K 7/10811 Focalisation
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners

Abstract

In an exemplary embodiment, a hand-held bar code reader has an elongated relatively narrow hand grip portion and an enlarged reader head portion with an extended window of greater width than the hand grip portion. Light energy is directed outwardly through the extended window so as to flood a bar code sensing region in front of the window having a depth dimension of at least about ten millimeters, and an optical system focuses bar code patterns in the sensing region onto an image plane in the reader unit with a resolution so as to read bars/spaces with a minimum width of about 0.0075 inch, or even less. Preferably the lens system provides a depth of focus for such bar code patterns of at least ten millimeters, so that a bar code pattern of marked curvature can be read in its entirety by means of an instant reading operation.

Claims

1. A portable instant reader comprising:

a hand-held reader unit, said hand-held reader unit having a portion thereof defining at least in part an illumination window, a flashable illuminator disposed near said illumination window and means for producing a flash of light therethrough;

said hand-held reader unit having a portion thereof defining at least, in part, a light receiving window for receiving reflections of light emitted through said illumination window;

a photodetector positioned within said hand-held reader in the path of light rays reflected into and through said light receiving window;

a light gathering means positioned between said light receiving window and said photodetector for receiving a light pattern from said light receiving window and focusing the same onto said photodetector;

said light gathering means comprising a lens system with a sensing field in front of said window having a width of at least about fifty millimeters, said photodetector having an image plane for receiving an image of a pattern in said sensing field, and said light gathering means comprising a lens system providing a resolution at the image plane of at least forty line pairs per millimeter with a depth of focus of at least ten millimeters in front of said window.

2. A portable instant reader in accordance with claim 1 with electronic means for reading a light pattern received by the photodetector, for assessing the validity of information represented thereby, and for automatically repeating the actuation of the flashable illuminator in the absence of a valid reading.

3. A portable instant reader according to claim 2, with an optical system comprising said lens system having a reading capability at a distance in front of said window of at least about twenty millimeters, and with an optimum focal plane about six millimeters in front of said window.

4. A portable instant reader comprising:

a hand-held unit having illumination and light receiving window means;

a flash illuminating device positioned behind said window means;

said flash illuminating device and window means being configured to distribute light across a surface containing information being read by said reader, said window means being configured to receive light reflected from the surface;

a photodetector disposed within the reader;

lens means for casting an image of light received through said window means onto said photodetector;

said flash illuminating device comprising elliptical-effect reflector means having a light source at a near focal point thereof, and having a second focal point disposed in front of said window means, such that the elliptical axis for said elliptical-effect reflector means extends obliquely relative to said window means.

5. A portable instant reader according to claim 4 with said elliptical-effect reflector means having its second focal point lying generally in a sensing field region aligned with said lens means.

6. A portable instant reader according to claim 4 with said lens means having an optical axis extending through said window means and through a sensing field region in front of said window means and intersecting said elliptical axis at a substantial distance from said window means.

7. An electroptical pattern recognition reader comprising:

a flashable illuminator;

means for triggering the flashable illuminator;

means for positioning the flashable illuminator in such relation to a pattern so as to illuminate the same and develope a reflected light signal therefrom upon the triggering of said flashable illuminator;

an optoelectronic spatial sensor means;

lens means for producing an image of said pattern from said reflected light signal and focusing the same onto said optoelectronic spatial sensor means;

said lens means providing a resolution of at least about forty line pairs per millimeter for patterns at any depth over a distance of about ten millimeters along the optical axis of the lens means and external to the reader.

8. A reader according to claim 7, with said lens means having effective marginal rays, directed at angles of about plus and minus fifteen degrees to the optical axis.

9. In a portable bar code reader

a hand-held bar code reader unit having an elongated relatively narrow hand grip portion for grasping in the hand of a user and having an enlarged reader head portion of greater width than said hand grip portion,

said elongated hand grip portion having a length and cross sectional configuration so as to be grasped by the hand with all fingers in gripping relation thereto,

said reader head portion having extended window means with a width dimension greater than the width of said hand grip portion which is to be gripped by the fingers of a hand,

extended light source means in said reader head portion for producing a sheet of light energy directed outwardly from the reader head portion through said window means over substantially the entire width of said window means so as to flood a bar code sensing region in front of said window means having a width dimension approximately equal to the width of said window means, having a depth dimension equal to at least about ten millimeters and a height dimension equal to at least about one millimeter, such that a bar code pattern in the sensing region will reflect light from said extended light source means along an optical axis directed generally normal to said window means, and

lens means for focusing bar code patterns in said sensing region onto an image plane in said reader unit with a resolution of about forty line pairs per millimeter.

15. In a portable reader according to claim 9, said lens means focusing patterns with said resolution of about forty line pairs per millimeter over a depth range of about ten millimeters in said sensing region, and means comprising said reader unit for reading patterns with marked curvature with said resolution of about forty line pairs per millimeter over said depth range of about ten millimeters.

16. In a portable reader according to claim 9, said reader head portion having a first mirror means spaced from said window means along said optical axis for receiving reflected light from a pattern in the sensing region and for re-reflecting such light along a second optical axis directed generally toward said window means, and having a second mirror means nearer to said window means than said first mirror means, said second mirror means being disposed relative to said second optical axis so as to direct light from the first mirror means along a third optical axis toward said lens means, and said lens means being located more remote from said window means than said second mirror means.

17. In a portable reader according to claim 16, said lens means having stop aperture means providing an aperture for light directed parallel to the third axis with a width dimension in a lateral direction which corresponds with the high resolution direction of a pattern in the sensing region, said width dimension of said aperture being not more than about two millimeters.

18. In a portable reader according to claim 15, said lens means having stop aperture means with an aperture of a width dimension of not more than about two millimeters in a lateral direction corresponding to the high resolution direction of the pattern.

19. In a portable reader according to claim 17, the lens means causing lateral marginal rays of the light energy from the second mirror means which lie in a lateral plane corresponding to the high resolution direction of the pattern to converge in the vicinity of said aperture and thereafter to diverge so as to occupy a laterally extended region at the image plane of the reader unit, said second mirror means having an operative width between the lateral marginal rays generally corresponding to the lateral extent of the image of the pattern at said image plane of the reader unit.

20. In a portable reader according to claim 9, said lens means having stop aperture means with an aperture having a width dimension in a lateral direction which corresponds with the high resolution direction of a pattern in the sensing region, and having a height dimension in a direction at right angles to said lateral direction, and corresponding to a longitudinal direction of an elongated pattern in the sensing region, the ratio of the height dimension of said aperture to said width dimension being at least about two to one.

10. The method of reading bar code patterns which comprises:

(a) receiving a light image from a sensing region having a width dimension greater than the length of the total bar code pattern and of a substantial height dimension greater than one millimeter,

(b) converging the rays of said light image to pass through a narrow non-circular aperture,

(c) focusing the light image onto a light receiving region of a photodetector having a resolution sufficient to sense a predetermined bar code, and

(d) reading out the individual elements of the light image focused on the photodetector for processing into bar code data.

11. The method of claim 10, where the photodetector has a predetermined operative length dimension in a direction of high resolution along which the focussed light image is to impinge,

the converging of the rays of said light image being such as to pass through an aperture having a width dimension substantially not greater than two millimeters,

said method further comprising causing the rays of the light image passing through said aperture to diverge as they are focused so as to impinge over substantially the entire operative length dimension of the light receiving region of the photodetector, while blocking from the photodetector all light rays not passing through said aperture.

12. The method of claim 10, said method further comprising directing light rays reflected from a sensing region having a depth of at least about ten millimeters through said aperture, and onto said photodetector with a depth of focus of at least about ten millimeters and a resolution of about forty line pairs per millimeter.

13. The method of claim 10, said method further comprising filtering out a long wavelength region of the spectrum of light energy from the sensing region prior to passage of the light energy through said aperture.

14. The method of claim 12, said method further comprising filtering out a long wavelength region of the spectrum of light energy from the sensing region prior to passage of the light energy through said aperture.