Apparatus and method for measuring optical characteristics of an object

• US 6,590,660 B2
• Filed: 03/21/2002
• Issued: 07/08/2003
• Est. Priority Date: 12/23/1999
• Status: Expired due to Fees

• Current Assignee: RPX Corporation
• Original Assignee: LJ Laboratories L.L.C.
• Inventors: Jung, Wayne D., Jung, Russell W., Loudermink, Alan R.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US10/103,514
• Publication Number:
  US 20030016359A1
• Time in Patent Office: 474 Days
• Field of Search: 356/416, 356/417, 356/419, 356/414, 356/71, 250/226
• US Class Current: 356/419
• CPC Class Codes: G01J 1/0407 Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
• CPC Class Codes: G01J 1/0433 using notch filters
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/0474 Diffusers cavities G01J2001/0481
• CPC Class Codes: G01J 1/06 Restricting the angle of incident light
• CPC Class Codes: G01J 2001/0481 Preset integrating sphere or cavity
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/021 using plane or convex mirrors, parallel phase plates, or particular reflectors
• CPC Class Codes: G01J 3/0216 using light concentrators or collectors or condensers
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0227 using notch filters
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0251 Colorimeters making use of an integrating sphere
• CPC Class Codes: G01J 3/0259 Monolithic
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• CPC Class Codes: G01J 3/0278 Control or determination of height or angle information for sensors or receivers
• CPC Class Codes: G01J 3/0283 using a charging unit
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/10 : Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/2803 : using photoelectric array detector
• CPC Class Codes: G01J 3/508 : measuring the colour of teeth
• CPC Class Codes: G01J 3/51 : using colour filters
• CPC Class Codes: G01J 3/513 : having fixed filter-detector pairs

Abstract

Optical characteristic measuring systems and methods such as for determining the color or other optical characteristics of teeth are disclosed. Perimeter receiver fiber optics preferably are spaced apart from a source fiber optic and receive light from the surface of the object/tooth being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object/tooth being measured. Under processor control, the optical characteristics measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence, gloss and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention. A method of producing dental prostheses based on measured data also is disclosed. Measured data also may be stored and/or organized as part of a patient data base. Such methods and implements may be desirably utilized for purposes of detecting and preventing counterfeiting or the like. Low cost and small form factor spectrometers, and methods for manufacturing the same, also are disclosed.

Claims

1. A spectrometer assembly, comprising:

a substrate having thereon a plurality of optical sensors and one or more processing elements;

a plurality of interference filter elements fixedly positioned over at least a first group of the sensors and fixedly positioned with respect to the substrate, wherein the plurality of filter elements have spectral transmission characteristics over one or more predetermined spectral bands;

an optical manifold fixedly positioned over at least certain of the plurality of filter elements and fixedly positioned with respect to the substrate, wherein the optical manifold has a plurality of exit port areas and at least one entrance port area, wherein light entering the entrance port area is transmitted to an interior portion of the optical manifold, wherein at least a portion of the light is transmitted from the exit port areas through at least certain of the filter elements and is sensed by at least certain of the sensors; and

a spacer element positioned between the plurality of exit port areas and the plurality of interference filter elements, wherein the spacer element limits the angle of incidence of light that is incident on the plurality of interference filter elements;

wherein light may be coupled to the entrance port area, wherein at least first spectral data corresponding to the light is generated by the one or more processing elements, wherein the spectrometer assembly is fabricated in a fixed manner with respect to the substrate.

2. The assembly of claim 1, wherein the sensors comprise sensors that generate at least one signal having a frequency proportional to the light intensity received by the sensors.

3. The assembly of claim 2, wherein the at least one signal comprises a TTL or CMOS digital signal.

4. The assembly of claim 2, wherein one or more spectral characteristics are determined based on measuring a period of a plurality of digital signals produced by a plurality of sensors.

5. The assembly of claim 2, wherein the sensors comprise a plurality of light to frequency converter sensing elements.

6. The assembly of claim 1, wherein a spectral analysis is performed based on light received from an object or material.

7. The assembly of claim 1, wherein the filter elements collectively comprise a color gradient filter.

8. The assembly of claim 1, wherein the filter elements collectively comprise a filter grid.

9. The assembly of claim 1, wherein received light is spectrally analyzed without using a diffraction grating.

10. The assembly of claim 1, wherein the light coupled to the entrance port area is received by a probe, wherein a plurality of measurements are taken at a plurality of distances of the probe with respect to an object pr material.

11. The assembly of claim 1, wherein a probe having one or more light sources provides light to an object or material, wherein light from one or more light sources is received by one or more light receivers from the object or material and coupled to the entrance port area.

12. The assembly of claim 11, wherein one or more sensors determine a distance of the probe with respect to the object or material.

13. The assembly of claim 11, wherein one or more sensors determine an angle of the probe with respect to the object or material.

14. The assembly of claim 11, wherein one or more sensors determine a distance and an angle of the probe with respect to the object or material.

15. The assembly of claim 2, wherein the at least one signal having a frequency proportional to the light intensity received by the sensors is generated by an integrator coupled to the sensors.

16. The assembly of claim 1, wherein the sensors comprise a photo diode array.

17. The assembly of claim 1, wherein the light is collimated prior to being sensed by the sensors.

18. The assembly of claim 17, wherein the light is collimated by an aspheric lens or lens assembly.

19. The assembly of claim 1, wherein the light is provided by one or more light sources to an object or material.

20. The assembly of claim 19, wherein characteristics of the object or material are determined.

21. The assembly of claim 20, wherein the characteristics comprise spectral characteristics.

22. The assembly of claim 20, wherein the characteristics comprise whether the object or material contains a predetermined material.

23. The assembly of claim 20, wherein a determination is made if the object or material is genuine.

24. The assembly of claim 19, wherein the object or material comprises a gaseous material, a non-gaseous material, skin, non-skin body tissue, paint, fabric, a photograph, a dental object, a printed object, hair, or makeup.

25. The assembly of claim 1, further comprising a bias light source, wherein the bias light source provides bias light to at least certain of the sensors.

26. The assembly of claim 1, further comprising a probe providing light to a surface of an object or material and receiving light from the object or material, wherein light is provided from the probe by at least one light source and light is received by one or more light receivers, wherein the light source and one or more of the light receivers define a critical height from the surface below which no light from the light source that is specularly reflected from the object or material is received by the one or mo of the light receivers.

27. The assembly of claim 26, wherein the assembly takes at least one measurement with the probe below the critical height for one or more of the light receivers.

28. The assembly of claim 1, further comprising a blocking filter, wherein the blocking filter blocks light outside of a spectral resolution range of the assembly.

29. The assembly of claim 1, wherein the exit port areas are of non-uniform size.

30. The assembly of claim 29, wherein a first exit port area corresponding to a sensor receiving light from a filter element that passes light from a blue portion of a spectrum of light received by the assembly has a size greater than a second exit port area corresponding to a sensor receiving light from a filter element that passes light from a red portion of the spectrum of light received by the assembly.

31. The assembly of claim 1, further comprising a non-coherent light guide, wherein light from the non-coherent light guide is coupled to the at least one entrance port area.

32. The assembly of claim 1, wherein the optical manifold comprises an optical block.

33. The assembly of claim 1, wherein the optical block comprises quartz or a poly-optic material.

34. The assembly of claim 32, wherein the optical block has mirrored surfaces.

35. The assembly of claim 32, wherein the optical block includes a surface that includes the plurality of exit port areas.

36. The assembly of claim 35, wherein the surface of the optical block that includes the plurality of exit port areas is contoured.

37. The assembly of claim 36, wherein the contoured surface of the optical block provides lens for at least certain of the plurality of exit port areas.

38. The assembly of claim 26, wherein light is coupled to the one or more light receivers through a barrier.

39. The assembly of claim 38, wherein the barrier has a thickness less than the critical height.

40. The assembly of claim 39, wherein the barrier provides an infection control implement.

41. The assembly of claim 39, wherein the barrier comprises a material that is disposable or cleanable.

42. A spectrometer assembly, comprising:

a substrate having thereon a plurality of optical sensors and one or more processing elements;

a plurality of filter elements fixedly positioned over at least a first group of the sensors and fixedly positioned with respect to the substrate, wherein the plurality of filter elements have spectral transmission characteristics over one or more predetermined spectral bands; and

an optical manifold fixedly positioned over at least certain of the plurality of filter elements and fixedly positioned with respect to the substrate, wherein the optical manifold has a plurality of exit port areas and at least one entrance port area, wherein light entering the entrance port area is transmitted to an interior portion of the optical manifold, wherein at least a portion of the light is transmitted from the exit port areas through at least certain of the filter elements and is sensed by at least certain of the sensors;

wherein the plurality of optical sensors include a plurality of sets of sensors, wherein a set of sensors is associated with each of the filter elements, wherein a first set of sensors associated with a filter element that passes light from a blue portion of a spectrum of light received by the assembly has a greater number of sensors than a second set of sensors associated with a filter element that passes light from a red portion of the spectrum of light received by the assembly;

wherein light may be coupled to the entrance port area, wherein at least first spectral data corresponding to the light is generated by the one or more processing elements, wherein the spectrometer assembly is fabricated in fixed manner with respect to the substrate.

43. The assembly of claim 42, wherein the sensors comprise sensors that generate at least one signal having a frequency proportional to the light intensity received by the one or more sensors.

44. The assembly of claim 43, wherein the sensors comprise a plurality of light to frequency converter sensing elements.

45. The assembly of claim 42, wherein the biter elements collectively comprise a color gradient filter.

46. The assembly of claim 42, wherein the filter elements collectively comprise a filter grid.

47. The assembly of claim 42, wherein received light is spectrally analyzed without using a diffraction grating.

48. The assembly of claim 42, wherein the light coupled to the entrance port area is received by a probe, wherein a plurality of measurements are taken at a plurality of distances of the probe with respect to an object or material.

49. The assembly of claim 42, wherein a probe having one or more light sources provides light to an object or material, wherein light from one or more light sources is received by one or more light receivers from the object or material and coupled to the entrance port area.

50. The assembly of claim 49, wherein one or more sensors determine a distance of the probe with respect to the object or material.

51. The assembly of claim 49, wherein one or more sensors determine an angle of the probe with respect to the object or material.

52. The assembly of claim 49, wherein one or more sensors determine a distance and an angle of the probe with respect to the object or material.

53. The assembly of claim 42, herein the sensors comprise a photo diode array.

54. The assembly of claim 42, wherein the light is collimated prior to being sensed by the sensors.

55. The assembly of claim 54, wherein the light is collimated by an aspheric lens or lens assembly.

56. The assembly of the claim 42, wherein the light is provided by one or more light sources to an object or material.

57. The assembly of claim 56, wherein characteristics of the object or material are determined.

58. The assembly of claim 57, wherein the characteristics comprise spectral characteristics.

59. The assembly of claim 57, wherein the characteristics comprise whether the object or material contains a predetermined material.

60. The assembly of claim 57, wherein a determination is made if the object or material is genuine.

61. The assembly of claim 56, wherein the object or material comprises a gaseous material, a non-gaseous material, skin, non-skin body tissue, paint, fabric, a photograph, a dental object a printed object, hair, or makeup.

62. The assembly of claim 42, further comprising a bias light source, wherein the bias provides bias light to at lent certain of the sensors.

63. The assembly of claim 42, further comprising a probe providing light to a surface of an object or material and receiving light from the object or material, wherein light is provided from the probe by at least one light source and light is received by one or more light receivers, wherein the light source and one or more of the light receivers define a critical height from the surface below which no light from the light source that is specularly reflected from the object or material is received by the one or more of the light receivers.

64. The assembly of claim 63, wherein the assembly takes at least one measurement with the probe below the critical height for one or more of the light receivers.

65. The assembly of claim 42, further comprising a blocking filter, wherein the blocking filter blocks light outside of a spectral resolution range of the assembly.

66. The assembly of claim 42, wherein the exit port areas are of non-uniform size.

67. The assembly of claim 66, wherein a first exit port area corresponding to a sensor receiving light from a filter element that passes light from a blue portion of a spectrum of light received by the assembly has a size greater than a second exit port area corresponding to a sensor receiving light from a filter element that passes light from a red portion of the spectrum of light received by the assembly.

68. The assembly of claim 42, further comprising a non-coherent light guide, wherein light from the non-coherent light guide is coupled to the at least one entrance port area.

69. The assembly of claim 42, wherein the optical manifold comprises an optical block.

70. The assembly of claim 69, wherein the optical block comprises quartz or a poly-optic material.

71. The assembly of claim 69, wherein the optical block has mirrored surfaces.

72. The assembly of claim 69, wherein the optical block includes a surface that includes the plurality of exit port areas.

73. The assembly of claim 72, wherein the surface of the optical block that includes the plurality of exit port areas is contoured.

74. The assembly of claim 73, wherein the contoured surface of the optical block provides lens for at least certain of the plurality of exit port areas.

75. The assembly of claim 72, wherein an optical mask is adjacent the surface that includes the plurality of exit port areas.

76. The assembly of claim 75, wherein the optical mask controls angles of light that is received by the sensors.

77. The assembly of claim 63, wherein light is coupled to the one or more light receivers through a barrier.

78. The assembly of claim 77, wherein the barrier has a thickness less than the critical height.

79. The assembly of claim 78, wherein the barrier provides an infection control implement.

80. The assembly of claim 78, wherein the barrier comprises a material that is disposable or cleanable.