Optical reader having illumination assembly including improved aiming pattern generator

• US 6,060,722 A
• Filed: 09/24/1997
• Issued: 05/09/2000
• Est. Priority Date: 05/15/1995
• Status: Expired due to Term

• Current Assignee: Welch Allyn Data Collection Inc (Welch Allyn Incorporated)
• Original Assignee: Welch Allyn Data Collection Inc (Welch Allyn Incorporated)
• Inventors: Havens, William H., Hennick, Robert J., Pidhirny, John M.
• Primary Examiner(s): Allen, Stephone B.
• Application Number:
  US08/936,320
• Time in Patent Office: 958 Days
• Field of Search: 250/566, 250/568, 235/462.01, 235/462.02, 235/462.03, 235/462.2, 235/462.21, 235/462.32, 235/462.41
• US Class Current: 250/566
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 7/10732 Light sources

Abstract

An optical assembly for use with optoelectronic readers. An imaging optical assembly having an imaging optical axis forms an image of a two-dimensional region on an optoelectronic imaging device. An aiming pattern generator including at least a point-like aiming light source and an interferometric pattern generating optical element project onto the two-dimensional region a luminous aiming pattern that approximately coincides with the field of view of the imaging device. The aiming optical axis of the aiming pattern remains approximately coincident with the field of view of the imaging device over the range of reader-to-target distances over which the reader is used.

Claims

1. An optical assembly for use with optoelectronic readers including, in combination:

a) an imaging device for generating an electrical signal that varies in accordance with light received from a two-dimensional region;

b) an imaging optics assembly for forming an image of said two-dimensional region on said imaging device, said imaging optics assembly having an imaging optical axis and serving to define the field of view of said imaging device;

c) an aiming pattern generator, including at least an aiming light source and an interferometric pattern generating optic element, for generating and projecting toward said two-dimensional region an aiming pattern that approximately coincides with the field of view of said imaging device, said aiming pattern having an aiming optical axis; and

d) means for mounting said imaging optics assembly and said aiming pattern generator in proximity to one another with said imaging optical axis disposed approximately parallel to said aiming optical axis.

2. The optical assembly of claim 1 in which said mounting means comprises at least one molded article, said at least one molded article defining (i) a light shield for shielding said imaging device from ambient light, (ii) a first opening for receiving said imaging optics assembly, and (iii) a second opening for receiving said aiming pattern generator.

3. The optical assembly of claim 1 further including a plurality of illuminating light sources for illuminating said two-dimensional region, and a substrate for supporting said light sources.

4. The optical assembly of claim 2 further including a plurality of illuminating light sources for illuminating said two-dimensional region, and a substrate for supporting said light sources.

5. The optical assembly of claim 4 in which said substrate is attached to said at least one molded article.

6. The optical assembly of claim 5 in which said substrate defines at least one opening through which said imaging optics assembly may receive light from said region and through which said aiming pattern generator may project light toward said region.

7. The optical assembly of claim 3 further including means for concentrating light emitted by said illuminating light sources in the direction of said region.

8. The optical assembly of claim 3 further including a light director member, disposed in proximity to said light sources, for reflectively directing light emitted by said light sources toward said region.

9. The optical assembly of claim 6 further including a light director member, disposed in proximity to said light sources, for reflectively directing light emitted by said light sources toward said region.

10. The optical assembly of claim 7 in which said concentrating means, said substrate, said illuminating light sources, said at least one molded article, said imaging device, said imaging optics assembly, and said aiming pattern generator together form a compact unitary assembly having a length, in directions parallel to said imaging optical axis, which is relatively small in comparison with the distance between said optical assembly and said region.

11. The optical assembly of claim 10 in which said imaging optics assembly has a back focal length that is between about 0.3 mm and 13 mm.

12. The optical assembly of claim 1 in which said aiming light source is a point-like light source, and in which said pattern generating optic element comprises one of a diffractive optic element, and a holographic optic element.

13. The optical assembly of claim 1 in which said pattern generating element comprises a Fresnel type optic element.

14. The optical assembly of claim 12 in which said point-like light source is one of a solid state laser and a resonant cavity light emitting diode.

15. The optical assembly of claim 12 further including a collimating assembly disposed between said aiming light source and said pattern generating optic element.

16. The optical assembly of claim 1 in which said imaging optical axis and said aiming optical axis converge in the direction of said region.

17. The optical assembly of claim 1 in which said imaging and aiming optical axis intersect one another at a location between said optical assembly and the region to be imaged by said imaging device.

18. The optical assembly of claim 1 in which said imaging optics assembly serves to define the depth of field of said optical assembly, and in which said imaging and aiming optical axis intersect one another within said depth of field.

19. The optical assembly of claim 1 in which said aiming pattern indicates the approximate extent of at least one dimension of said field of view.

20. The optical assembly of claim 18 in which the angle between said imaging optical axis and said aiming optical axis is such that said aiming pattern and the portion of said region that is within said field of view are both within said depth of field.

21. An optical assembly for use with an optoelectronic reader including, in combination:

a) optoelectronic imaging means for generating an electrical representation of a two-dimensional image formed thereon;

b) optical imaging means for receiving light from a two-dimensional target region and forming a two-dimensional image of said region on said optoelectronic imaging means, said optical imaging means having an imaging optical axis;

c) aiming means, including at least an aiming light source and an interference pattern generating member, for projecting a pattern of light onto said target region and thereby indicating the approximate extent of the field of view of said optoelectronic imaging means, said aiming means having an aiming optical axis; and

d) means for so positioning said optical means and said aiming means relative to one another that they having approximately the same vantage point with respect to said region.

22. The optical assembly of claim 21 in which said positioning means comprises at least one molded article, said at least one molded article defining (i) a light shield for shielding said optical imaging means from ambient light, (ii) a first opening for receiving said optical imaging means, and (iii) a second opening for receiving said aiming means.

23. The optical assembly of claim 21 further including a plurality of illuminating light sources for illuminating said two-dimensional target region, and a substrate for supporting said illuminating light sources.

24. The optical assembly of claim 22 further including a plurality of illuminating light sources for illuminating said two-dimensional target region, and a substrate for supporting said illuminating light sources.

25. The optical assembly of claim 24 in which said substrate is attached to said at least one molded article.

26. The optical assembly of claim 25 in which said substrate defines at least one opening through which said optical imaging means may receive light from said region and through which said aiming means may project said pattern of light toward said region.

27. The optical assembly of claim 23 further including a light concentrator for concentrating light emitted by said illuminating light sources in the direction of said region.

28. The optical assembly of claim 23 further including a light director member, disposed in proximity to said illuminating light sources, for reflectively directing light emitted by said illuminating light sources toward said region.

29. The optical assembly of claim 26 further including a light director member, disposed in proximity to said illuminating light sources, for reflectively directing light emitted by said illuminating light sources toward said region.

30. The optical assembly of claim 27 in which said light concentrator, said substrate, said illuminating light sources, said at least one molded article, said optoelectronic imaging means, said optical imaging means, and said aiming means together form a compact unitary assembly having a length, in directions parallel to said imaging optical axis, which is relatively small in comparison with the distance between said optical assembly and said region.

31. The optical assembly of claim 30 in which said imaging optics assembly has a back focal length that is between about 0.3 mm and 13 mm.

32. The optical assembly of claim 21 in which said aiming light source is a point-like light source, and in which said interference pattern generating optic member comprises one of a diffractive optic member, and a holographic optic member.

33. The optical assembly of claim 21 in which said interference pattern generating member is a Fresnel type optic member.

34. The optical assembly of claim 32 in which said point-like light source is one of a solid state laser and a resonant cavity light emitting diode.

35. The optical assembly of claim 32 further including a collimating assembly disposed between said point-like light source and said interference pattern generating member.

36. The optical assembly of claim 21 in which said imaging optical axis and said aiming optical axis converge in the direction of said region.

37. The optical assembly of claim 21 in which said imaging and aiming optical axis intersect one another at a location between said optical assembly and the region to be imaged by said optoelectronic imaging means.

38. The optical assembly of claim 21 in which said optical imaging means serves to define the depth of field of said optical assembly, and in which said imaging and aiming optical axis intersect one another within said depth of field.

39. The optical assembly of claim 21 in which said pattern of light indicates the approximate extent of at least one dimension of said field of view.

40. The optical assembly of claim 38 in which the angular displacement between said imaging optical axis and said aiming optical axis is sufficiently small that both said aiming pattern and said target region are within said depth of field.