Hand held symbology reader illumination diffuser with aimer optics

• US 9,292,724 B1
• Filed: 08/20/2013
• Issued: 03/22/2016
• Est. Priority Date: 12/16/2004
• Status: Active Grant

• Current Assignee: Cognex Corporation
• Original Assignee: Cognex Corporation
• Inventors: Flgge, Kai, Nunnink, Laurens
• Primary Examiner(s): Franklin, Jamara
• Application Number:
  US13/971,320
• Time in Patent Office: 945 Days
• Field of Search: 235/472.01
• US Class Current: 1/1
• 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 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B

Abstract

An imager defines a field of view and an optical axis. An illuminator directs illumination towards a region of interest, the region of interest being an intended position of the object. A tapered translucent diffuser is concentrically aligned with the optical axis, and has a first distal end proximate to the imager, and a second distal end proximate to the region of interest. The tapered translucent diffuser includes a darkened region, the darkened region to absorb a portion of the illumination to substantially reduce reflection of the portion of the illumination toward the object. A light guide can be positioned proximate the first distal end and the imager, such that a second illuminator can generate an aimer beam that passes through the light guide to produce an aimer pattern on the object.

Claims

1. An apparatus for imaging a symbol on an object, the apparatus comprising:

a portable imaging system having an imager, the imager defining a field of view and an optical axis;

an illuminator to direct illumination towards a region of interest, the region of interest being an intended position of the symbol on the object;

a tapered translucent diffuser concentrically aligned with the optical axis, having a first distal end proximate to the imager, and a second distal end proximate to the region of interest, the tapered translucent diffuser tapering along the length of the tapered translucent diffuser from the first end toward the second end; and

the tapered translucent diffuser including a darkened section, the darkened section to absorb a portion of the illumination to substantially reduce reflection of the portion of the illumination toward the object.

2. The apparatus according to claim 1, further including an additional illuminator directed towards a semi-reflecting mirror, where the darkened region absorbs at least a portion of illumination not reflected by the semi-reflecting mirror.

3. The apparatus according to claim 2 further including a side diffuser to diffuse additional illumination from the additional illuminator.

4. The apparatus according to claim 1, wherein the darkened region is closer to the first distal end than the second distal end.

5. The apparatus according to claim 1, wherein the darkened region is substantially opaque.

6. The apparatus according to claim 1, wherein the tapered translucent diffuser has a first color characteristic and wherein the illuminator emits illumination having a color characteristic that matches the first color characteristic.

7. The apparatus according to claim 1, wherein the tapered translucent diffuser is composed of polymethyl methacrylate.

8. The apparatus according to claim 1, wherein the illumination directed towards the region of interest is diffused by the translucent diffuser to provide diffuse illumination to the field of view.

9. The apparatus according to claim 1, wherein the diffuser has a distal edge adjacent the region of interest and wherein the distal edge forms a recess in which at least a portion of an object including the symbol to be imaged is receivable.

10. The apparatus according to claim 1, wherein the illuminator further comprises a plurality of selectively actuated illuminators.

11. The apparatus according to claim 10, wherein the plurality of selectively actuated illuminators have a north-south and east-west selective actuation.

12. The apparatus according to claim 1, wherein illuminator light passes through the transparent diffuser toward the region of interest.

13. The apparatus according to claim 1, further comprising a light absorbing filter applied to the diffuser and disposed between the diffuser and the region of interest.

14. An apparatus for imaging a symbol on an object, the apparatus comprising:

a hand-held portable imaging system having an imager, the imager defining a field of view and an optical axis;

an illuminator to direct illumination towards a region of interest, the region of interest being an intended position of the symbol on the object;

a tapered translucent diffuser concentrically aligned with the optical axis, having a first distal end proximate to the imager, and a second distal end proximate to the region of interest, the translucent diffuser tapering along the length of the tapered translucent diffuser from the first end toward the second end;

a light guide proximate the first distal end and the imager; and

a second illuminator, the second illuminator to generate an aimer beam that passes through the light guide to produce an aimer pattern on the object.

15. The apparatus according to claim 14, wherein the aimer beam internally reflects within the light guide to maintain a substantially parallel relationship to the optical axis.

16. The apparatus according to claim 14, wherein the light guide internally reflects the aimer beam to move the aimer beam closer to the optical axis.

17. The apparatus according to claim 14, further including a semi-reflecting mirror disposed in front of a lens aligned with the optical axis configured to direct at least a portion of illumination reflected from the region of interest into the lens;

a second illuminator directing illumination at the semi-reflecting mirror so that at least a portion of the illumination from the second illuminator is directed towards the region of interest; and

a second diffuser disposed between the second illuminator and the semi-reflecting mirror.

18. The apparatus according to claim 17, wherein the illuminator has a first intensity, and the second illuminator has a second intensity, so as to configure the apparatus to produce a uniform distribution of illumination over the field of view at the region of interest.

19. The apparatus according to claim 17, wherein the illuminator and the second illuminator have different intensities.

20. The apparatus according to claim 14, wherein the illumination from the illuminator that is directed towards the region of interest is diffused by the translucent diffuser to provide diffuse illumination to the field of view.

21. An apparatus for imaging an object, the apparatus comprising:

a hand-held portable imaging system having an imager, the imager defining a field of view and an optical axis;

a first illuminator to direct illumination towards a region of interest, the region of interest being an intended position of the object;

a tapered translucent diffuser concentrically aligned with the optical axis, having a first distal end proximate to the imager, and a second distal end proximate to the region of interest, the tapered translucent diffuser tapering along the length of the tapered translucent diffuser from the first end toward the second end;

the tapered translucent diffuser including a darkened region, the darkened region to absorb a portion of the illumination to substantially reduce reflection of the portion of the illumination toward the object;

a light guide proximate the first distal end and the imager; and

a second illuminator, the second illuminator to generate an aimer beam that passes through the light guide to produce an aimer pattern on the object.

22. The apparatus according to claim 21, wherein the light guide is parallelogram shaped.