Diffuse surface illumination apparatus and methods

• US 6,661,521 B1
• Filed: 09/11/1998
• Issued: 12/09/2003
• Est. Priority Date: 09/11/1998
• Status: Expired due to Term

• Current Assignee: Omron Corporation
• Original Assignee: Robotic Vision Systems, Inc. (Acuity Brands, Inc.)
• Inventors: Stern, Howard
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Punnoose, Roy M.
• Application Number:
  US09/151,765
• Time in Patent Office: 1,915 Days
• Field of Search: 356/244, 356/121, 356/122, 356/445, 356/446, 356/256, 235/455, 235/462.42, 235/462.45, 235/469, 235/472.01, 362/252
• US Class Current: 356/446
• 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

Abstract

An illumination apparatus is provided for a hand-held imager preferably to provide diffuse illumination for encoded symbology carried directly upon an article (component, etc) or upon a substrate carried by an article. The illumination apparatus is disposed proximate the front of the hand-held imager and is configured to permit light reflected from the target to pass through the illumination apparatus and onto a CCD image receiver. An array of unlensed LED'"'"'s is disposed to cast approximately or substantially lambertian illumination in a direction away from the target to be imaged and into the hand-held housing to impinge upon surfaces of an illuminator to receive the illumination and, in turn, project efficient and diffuse dark field illumination through the array of unlensed LED'"'"'s and towards and onto a location where a target to be imaged would be disposed. The illumination apparatus further includes a bright field illumination source including a plurality of forward facing (towards the target) lensed LED'"'"'s.

Claims

1. A diffuse illumination apparatus to illuminate a target surface for electronic imaging of the target surface;

comprising;

(a) illuminator means for projecting diffuse illumination in a predetermined configuration and in a predetermined direction; and

(b) illumination means for casting illumination upon said illuminator means;

(c) at least a portion of a surface of said illuminator means, when illumination from said illumination means is cast thereupon, projecting said diffuse illumination in said predetermined direction opposite to said first predetermined direction and upon the target surface;

(d) said illuminator means being substantially bowl-shaped with a bottom wall and a peripheral side wall extending from and encircling said bottom wall, an inner surface of said bottom wall and an inner surface of said peripheral side wall having a diffusing finish applied thereto to provide said diffuse illumination.

2. The illumination apparatus of claim 1 wherein said diffusing finish may be either matte white, smooth red or white or rough chrome.

3. The illumination apparatus of claim 2 wherein said illumination means includes a predetermined illumination emitting means carried by an illumination carrier disposed in proximity to and for cooperation with said illuminator means and so that said illumination emitting means is disposed to face and cast illumination upon said diffusing finish of said bottom wall surface and side wall surface of said illuminator means.

4. The illumination apparatus of claim 3 wherein said illumination emitting means icludes an array of LED,s.

5. The illumination apparatus of claim 4 wherein each LED is an unlensed LED and casts approximately lambertian illumination upon said illuminator means.

6. The illumination apparatus of claim 5 including electrical conductor means interconnecting said unlensed LED'"'"'s into at least one electrical circuit.

7. The illumination apparatus of claim 6 wherein said electrical conductor means is applied to a surface of said illumination carrier.

8. The illumination apparatus of claim 7 wherein said electrical conductor means interconnects said unlensed LED'"'"'s into at least two separate electrical circuits and wherein each such electrical circuit terminates in connectors for electrically connecting same to a source of electrical power and to control means for determining the brightness and duration of illumination of said illumination emitting means.

9. The illumination apparatus of claim 8 wherein said illumination emitting means and said illuminator means are disposed for coaction so that diffuse illumination projected from said illuminator means passes through said illumination carrier and about said illumination emitting means and electrical conductor means.

10. The illumination apparatus of claim 9 wherein said unlensed LED'"'"'s and said electrical conductor means are sized and disposed so that when said diffuse illumination is projected from said illuminator, through said illumination carrier, shadows of said unlensed LED'"'"'s and electrical conductor means appear smeared out in relation to a target when brought into focus to be imaged.

11. The illumination apparatus of claim 10 wherein there are twelve unlensed LED'"'"'s spaced about a first circle carried by said illumination carrier and six unlensed LED'"'"'s spaced about a second concentric circle carried by said illumination carrier and which is relatively smaller than said first circle of unlensed LED'"'"'s.

12. The illumination apparatus of claim 10 wherein there are eight unlensed LED'"'"'s spaced about a first circle carried by said illumination carrier and four unlensed LED'"'"'s spaced about a second concentric circle carried by said illumination carrier and which is relatively smaller than said first circle of unlensed LED'"'"'s.

13. The illumination apparatus of claim 10 wherein there are ten unlensed LED'"'"'s spaced about a first circle carried by said illumination carrier and five unlensed LED'"'"'s spaced about a second concentric circle carried by said illumination carrier and which is relatively smaller than said first circle of unlensed LED'"'"'s.

14. The illumination apparatus of claim 3 wherein said illuminator means and said illumination means are sized and configured to be disposed in an electronic imager between an electronic image receiving device thereof and a front opening thereinto and so that light from images, reflected off a target to be imaged, passes along a predetermined image path through the illumination apparatus.

15. The illumination apparatus of claim 14 wherein said illuminator means includes an opening extending through a bottom wall thereof disposed in alignment with said predetermined image path and wherein said array of illumination emitting means is configured to provide a clear space through said illumination carrier for said predetermined image path.

16. The illumination apparatus of claim 3 wherein said illumination carrier includes a number of spoke-like ribs upon which said illumination emitting means are disposed.

17. The illumination apparatus of claim 3 wherein said illumination carrier includes a circular periphery and said illumination emitting means are carried by a circular ring disposed proximate said circular periphery.

18. The illumination apparatus of claim 3 wherein said illumination emitting means comprises a dark field illumination means and said illumination apparatus further includes a bright field illumination means including additional illumination emitting means which direct their illumination from said illumination carrier towards a target to be illuminated.

19. The illumination apparatus of claim 3 wherein said illumination emitting means comprises a dark field illumination means and said illumination apparatus further includes a bright field illumination means which directs its illumination from said illuminator means through said illumination carrier.

20. The illumination apparatus of claim 3 wherein said illumination carrier is substantially circular and of clear material.

21. The illumination apparatus of claim 3 wherein said illumination carrier is rectangular and of clear material.

22. The illumination apparatus of claim 3 wherein said bottom surface of said illuminator means has a freznel-like surface configuration facing towards said illumination carrier.

23. A method of providing diffuse illumination to illuminate a target surface for electronic imaging of the target surface;

comprising;

(a) arranging a plurality of illumination emitting devices into an array and so that each such device, when energized, will cast its illumination in a predetermined direction;

(b) providing an illuminator with at least a first diffusing surface and positioning said illuminator so that said light diffusing surface receives illumination from said illumination emitting devices and projects diffuse light along a predetermined light path and in a second predetermined direction opposite to said first predetermined direction and to be toward where a target surface might be positioned for imaging.

24. A method of providing diffuse illumination to illuminate a target surface for electronic imaging of the target surface, comprising:

(a) arranging a plurality of illumination emitting devices into an array and so that each such device, when energized, will cast its illumination in a first predetermined direction;

(b) positioning said array of illumination emitting devices onto a clear illumination carrier;

(c) providing an illuminator with at least a first diffusing surface and positioning said illuminator so that said light diffusing surface receives illumination from said illumination emitting devices and projects diffuse light along a predetermined light path and in a second predetermined direction opposite to said first predetermined direction and to be toward where a target surface might be positioned for imaging.

25. A method of providing diffuse illumination to illuminate a target surface for electronic imaging of the target surface , comprising:

(a) arranging a plurality of illumination emitting devices into an array and so that each such device, when energized, will cast its illumination in a first predetermined direction; and

(b) providing an illuminator with at least a first diffusing surface and positioning said illuminator so that said light diffusing surface receives illumination from said illumination emitting devices and projects diffuse light along a predetermined light path which extends through said array of illumination emitting devices and in a second predetermined direction opposite to said first predetermined direction and to be toward where a target surface might be positioned for imaging.

26. The method of claim 25 including selecting said illumination emitting devices of a predetermined size and electrically interconnecting said illumination emitting devices with electrical conductors of predetermined size and material and positioning said illumination emitting devices and electrical conductors to minimize shadows upon a target and/or so that shadows thereof on a target will be out of focus and appear to be smeared when imaged.

27. The method of claim 26 including utilizing unlensed LED'"'"'s without light directing components for said illumination emitting devices.

28. The method of claim 27 including utilizing nine unlensed LED'"'"'s in a first circuit and nine unlensed LED'"'"'s in a second circuit for said illumination devices array.

29. The method of claim 28 including selecting and positioning each said unlensed LED to provide lambertian illumination.

30. A method of providing diffuse illumination to illuminate a target surface for electronic imaging of the target surface, comprising:

(a) arranging a plurality of illumination emitting devices into an array and so that each such device, when energized, will cast its illumination in a first predetermined direction;

(b) providing an illuminator with at least a first diffusing surface and positioning said illuminator so that said light diffusing surface receives illumination from said illumination emitting devices and projects diffuse light along a predetermined light path and in a second predetermined direction opposite to said first predetermined direction and to be toward where a target surface might be positioned for imaging;

(c) utilizing said array of illumination emitting devices for dark field illumination; and

(d) providing a second array of illumination emitting devices for bright field illumination.

31. The method of claim 30 including positioning said second array of illumination emitting devices to cast their illumination in a second predetermined direction opposite to that of said first predetermined direction of said array of illumination emitting devices.

32. A method of providing diffuse illumination to illuminate a target surface for electronic imaging of the target surface, comprising:

(a) arranging a plurality of illumination emitting devices into an array and so that each such device, when energized, will cast its illumination in a first predetermined direction;

(b) providing an illuminator with at least a first diffusing surface and positioning said illuminator so that said light diffusing surface receives illumination from said illumination emitting devices and projects diffuse light along a predetermined light path and in a second predetermined direction opposite to said first predetermined direction and to be toward where a target surface might be positioned for imaging; and

(c) positioning said illuminator and said plurality of illumination emitting devices so that light reflected from a target will pass through said illuminator and illumination emitting devices.

33. The method of claim 32 including forming said illuminator with an opening and forming said array of illumination emitting devices with a spacing so that light reflected from a target may be transmitted therethrough.

34. An imager for electronically capturing and decoding data carrying symbology;

comprising;

(a) housing means;

(b) CCD image receiving means disposed within said housing means;

(c) camera engine means disposed within said housing means to capture an image of symbology and present same to sa id CCD image receiving means;

(d) illumination apparatus including;

(i) illuminator means for projecting diffuse illumination in a predetermined configuration and in a predetermined direction;

(ii) illumination means for casting illumination upon said illuminator means; and

(iii) at least a portion of a surface of said illuminator means, when illumination from said illumination means is cast thereupon, projecting said diffuse illumination in said predetermined direction opposite to said first predetermined direction and upon the data carrying symbology, when disposed in proximity thereto, such that the data carrying symbology is presented to said camera engine means for capture thereby,

(c) said illuminator means being substantially bowl-shaped with a bottom wall and a peripheral side wall extending from and encircling said bottom wall, an inner surface of said bottom wall and an inner surface of said peripheral side wall having a diffusing finish applied thereto to provide diffuse illumination.

35. The imager of claim 34 wherein said diffusing finish may be either matte white, smooth red or white or rough chrome.

36. The imager of claim 35 wherein said illumination means includes a predetermined array of lambertian illumination emitting means carried by an illumination carrier disposed in proximity to and for cooperation with said illuminator means and so that said illumination emitting means are disposed to face and cast their respective lambertian illumination upon said diffusing finish of said bottom wall surface and side wall surface of said illuminator.

37. The imager of claim 36 wherein each said illumination emitting means is an LED.

38. The imager of claim 37 wherein each LED is an unlensed LED.

39. The imager of claim 38 including electrical conductor means interconnecting said unlensed LED'"'"'s into at least one electrical circuit.

40. The imager of claim 39 wherein said electrical conductor means is applied to a surface of said illumination carrier.

41. The imager of claim 40 wherein said electrical conductor means interconnects said unlensed LED'"'"'s into at least two separate electrical circuits and wherein each such electrical circuit terminates in connectors for electrically connecting same to a source of electrical power and to control means for determining the brightness and duration of illumination of said illumination emitting means.

42. The imager of claim 41 wherein said illumination emitting means and said illuminator means are disposed for co-action so that diffuse illumination projected from said illuminator means passes through said illumination carrier and about said illumination emitting means and electrical conductor means.

43. The imager of claim 42 wherein said unlensed LED'"'"'s and said electrical conductor means are sized and disposed so that when said diffuse illumination is projected from said illuminator through said illumination carrier shadows of said unlensed LED'"'"'s and electrical conductor means appear smeared out in relation to a target when brought into focus to be imaged.

44. The imager of claim 43 wherein there are twelve unlensed LED'"'"'s spaced about a first circle carried by said illumination carrier and six unlensed LED'"'"'s spaced about a second concentric circle carried by said illumination carrier and which is relatively smaller than said first circle of unlensed LED'"'"'s.

45. The imager of claim 43 wherein there are eight unlensed LED'"'"'s spaced about a first circle carried by said illumination carrier and four unlensed LED'"'"'s spaced about a second concentric circle carried by said illumination carrier and which is relatively smaller than said first circle of unlensed LED'"'"'s.

46. The imager of claim 43 wherein there are ten unlensed LED'"'"'s spaced about a first circle carried by said illumination carrier and five unlensed LED'"'"'s spaced about a second concentric circle carried by said illumination carrier and which is relatively smaller than said first circle of unlensed LED'"'"'s.

47. The imager of claim 36 wherein said illuminator means and said illumination means are sized and configured to be disposed in the imager between said CCD image receiving means thereof and a front opening thereinto and so that images reflected off a target to be imaged pass along a predetermined image path through the illumination apparatus.

48. The imager of claim 47 wherein said illuminator means includes an opening extending through a bottom wall thereof disposed in alignment with said predetermined image path and wherein said array of illumination emitting means is configured to provide a clear space through said illumination carrier for said predetermined image path.

49. The imager of claim 36 wherein said illumination carrier includes a number of spoke-like ribs upon which said illumination emitting means are disposed.

50. The imager of claim 36 wherein said illumination carrier includes a circular periphery and said illumination emitting means are disposed in a circular ring disposed proximate said circular periphery.

51. The imager of claim 36 wherein said illumination emitting means comprises a dark field illumination means and said illumination apparatus further includes a bright field illumination means including additional illumination emitting means which direct their illumination from said illumination carrier towards where a target would be disposed to be illuminated.

52. The imager of claim 36 wherein said illumination emitting means comprises a dark field illumination means and said illumination apparatus further includes a bright field illumination means which directs its illumination from said illuminator means through said illumination carrier.

53. The imager of claim 36 wherein said illumination carrier is substantially circular and of clear material.

54. The imager of claim 36 wherein said illumination carrier is rectangular and of clear material.

55. The imager of claim 36 wherein said bottom surface of said illuminator means has a freznel-like surface configuration facing towards said illumination carrier.

56. A diffuse illumination apparatus for illuminating a target surface for electronic imaging of the target surface, comprising:

(a) a plurality of illumination emitting devices arranged into an array and so that each such device, when energized, will cast its illumination in a first predetermined direction; and

(b) an illuminator having at least a first light diffusing surface and being positioned so that said light diffusing surface receives illumination from said illumination emitting devices and projects diffuse light along a predetermined light path which extends through said array of illumination emitting devices and in a second predetermined direction opposite to said first predetermined direction and toward where a target surface might be positioned for imaging.

57. The apparatus of claim 56 wherein said illumination emitting devices are of a predetermined size and are electrically interconnected with electrical conductors of predetermined size and material and are selectively positioned to minimize shadows upon a target and/or so that shadows thereof on a target will be out of focus and appear to be smeared when imaged.

58. The apparatus of claim 57 wherein said illumination emitting devices are unlensed LED'"'"'s without light directing components.

59. The apparatus of claim 58 wherein nine unlensed LED'"'"'s in a first circuit and nine unlensed LED'"'"'s in a second circuit are utilized for said illumination devices array.

60. The apparatus of claim 59 wherein each said unlensed LED is selected and positioned to provide lambertian illumination.

61. The apparatus of claim 56 wherein said array of illumination emitting devices are positioned onto a clear illumination carrier.

62. The apparatus of claim 56 wherein said array of illumination emitting devices may be utilized for dark field illumination and a second array of illumination emitting devices are provided for bright field illumination.

63. The apparatus of claim 62 wherein said second array of illumination emitting devices are positioned to cast their illumination in a second predetermined direction opposite to that of said first predetermined direction of said array of illumination emitting devices.

64. The apparatus of claim 56 wherein said illuminator and said plurality of illumination emitting devices are positioned so that light reflected from a target will pass through said illuminator and illumination emitting devices.

65. The apparatus of claim 64 wherein said illuminator is formed with an opening and said array of illumination emitting devices are arranged with a spacing so that light reflected from a target may be transmitted therethrough.

66. A diffuse illumination apparatus to illuminate a target surface for electronic imaging of the target surface, comprising:

(a) illumination means; and

(b) illuminator means positioned to receive upon a surface thereof illumination from said illumination means;

(c) at least a portion of said surface of said illuminator means, when illumination from said illumination means is received thereupon, diffusing said illumination and projecting said diffuse illumination in a predetermined direction;

(d) said illumination means directing its illumination towards said illuminator means and in an illumination direction opposite to said predetermined direction to illuminate a target surface when disposed in proximity thereto.

67. An imager for electronically capturing and decoding data carrying symbology;

comprising;

(a) housing means;

(b) CCD image receiving means disposed within said housing means;

(c) camera engine means disposed within said housing means to capture an image of symbology and present same to said CCD image receiving means; and

(d) illumination apparatus including;

(i) illumination means;

(ii) illuminator means positioned to receive upon a surface thereof illumination from said illumination means;

(iii) at least a portion of said surface of said illuminator means, when illumination from said illumination means is received thereupon, diffusing said illumination and projecting said diffuse illumination in a predetermined-direction and upon the data carrying symbology, when disposed in proximity thereto, such that the data carrying symbology is presented to said camera engine means for capture thereby;

(iv) said illumination means directing its illumination towards said illuminator means and in an illumination direction opposite to said predetermined direction.