Magnetoacoustic sensor system and associated method for sensing environmental conditions

• US 20060050765A1
• Filed: 04/23/2003
• Published: 03/09/2006
• Est. Priority Date: 04/25/2002
• Status: Active Grant

• Current Assignee: Glaxo Group Limited (Glaxosmithkline Holdings Ltd.)
• Original Assignee: Glaxo Group Limited (Glaxosmithkline Holdings Ltd.)
• Inventors: Walker, Dwight Sherod, James, Michael Bernard
• Granted Patent: US 7,429,127 B2
• Time in Patent Office: Days
• US Class Current: 374/109
• CPC Class Codes: G01K 11/26 of resonant frequencies
• CPC Class Codes: G01K 7/32 using change of resonant frequency of a crystal
• CPC Class Codes: G01K 7/36 using magnetic elements, e.g. magnets, coils magnetic elements per se H01F
• CPC Class Codes: G01N 2291/02845 Humidity, wetness
• CPC Class Codes: G01N 2291/02881 Temperature
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/2412 using the magnetostrictive properties of the material to be examined, e.g. electromagnetic acoustic transducers [EMAT]; investigating the presence of flaws using eddy currents G01N27/90, magnetostrictive transducers B06B1/08, measuring magnetostrictive properties G01R33/18
• CPC Class Codes: G01N 33/15 Medicinal preparations ; Physical properties thereof, e.g. dissolubility drug screening with animal cells G01N33/5008
• CPC Class Codes: G01N 5/025 for determining moisture content

Abstract

A remote sensor system (60) and method for passively sensing environmental conditions, such as temperature and humidity, uses a magnetic impulse from an AC interrogation coil (68) to stimulate a magnetoelastic sensor (62) to generate an acoustic signal (AE) at the resonant frequency of the magnetoelastic sensor (62). The acoustic signal (AE) is received by amplifier (74), detected and displayed (76). The systems and methods are particularly suited for detecting environmental conditions in commercial pharmaceutical packaging, such as blister packs.

Claims

1. A sensor system for sensing an environmental condition, comprising:

a sensor element having a resonant frequency in the range of 300-700 kHz, said sensor element being adapted to generate a resonant frequency signal in response to an AC magnetic pulse, said sensor element comprising a material that is responsive to at least one environmental condition;

an interrogation device adapted to provide said AC magnetic pulse;

a receiver adapted to detect said resonant frequency signal; and

a processor adapted to determine at least one value reflective of said environmental condition.

2. The sensor system of claim 1, wherein said sensor element comprises a magnetoelastic alloy.

3. The sensor system of claim 2, wherein said magnetoelastic alloy comprises a material selected from the group consisting of iron, cobalt, samarium, yttrium, gadolinium, terbium and dysprosium.

4. The sensor system of claim 2, wherein said magnetoelastic alloy comprises an iron based, amorphous metallic glass alloy.

5. The sensor system of claim 4, wherein said iron based, amorphous metallic glass alloy comprises Metglass™

2826.

6. The sensor system of claim 1, wherein said sensor element has a length in the range of approximately 3-5 mm, a width in the range of approximately 1-2 mm, and a thickness in the range of approximately 1-100 μ

m.

7. The sensor system of claim 6, wherein said sensor element has a length of approximately 4 mm, a width of approximately 1.5 mm, and a thickness of approximately 2 μ

m.

8. The sensor system of claim 7, wherein said sensor element is sized to said length and width via a laser.

9. The sensor system of claim 1, wherein said environmental condition comprises temperature.

10. The sensor system of claim 1, wherein said sensor element is coated with a moisture sensitive material.

11. The sensor system of claim 10, wherein said moisture sensitive material exhibits a change in mass in response to a change in a second environmental condition.

12. The sensor system of claim 11, wherein said second environmental condition comprises humidity.

13. The sensor system of claim 10, wherein said moisture sensitive material comprises a metallic oxide.

14. The sensor system of claim 10, wherein said moisture sensitive material comprises a polymeric material.

15. A sensor system for sensing an environmental condition in a containment structure, comprising:

a sensor element having a first resonant frequency, said sensor element being adapted to generate said first resonant frequency in response to a first AC magnetic pulse, said sensor element comprising a material that is responsive to at least one environmental condition;

an interrogation device adapted to provide at least said first AC magnetic pulse to said sensor element and a second AC magnetic pulse to said containment structure; and

signal processing means for determining a value reflective of said environmental condition, said signal processing means including a receiver and a processor, said receiver being adapted to receive at least a first sensor signal corresponding to said first resonant frequency and a reference signal from said containment structure, said reference signal being generated by said containment structure in response to said second AC magnetic pulse, and communicate said first sensor signal and reference signal to said processor,

said processor being adapted to receive said first sensor signal and said reference signal, determine a first resonant frequency value from said first sensor signal and a reference signal value from said reference signal, determine a second resonant frequency value by subtracting said reference signal value from said first resonant frequency value, perform a Fourier transformation using said second resonant frequency value to determine a third resonant frequency value, and determine at least one environmental condition value from said third resonant frequency value.

16. The sensor system of claim 15, wherein said interrogation device provides a first plurality of said first AC magnetic pulses and said sensor element generates a plurality of first resonant frequency signals in response to said first AC magnetic pulses.

17. The sensor system of claim 16, wherein said processor is adapted to determine a fourth resonant frequency value for each of said fourth resonant frequency signals and determine a fifth resonant frequency value by pre-correlating said fourth resonant frequency values.

18. The sensor system of claim 17, wherein said processor is further adapted to determine said second resonant frequency value by subtracting said reference signal value from said fifth resonant frequency value.

19. The sensor system of claim 15, wherein said sensor element has a resonant frequency in the range of 300-700 kHz.

20. The sensor system of claim 19, wherein said sensor element has a resonant frequency in the range of 500-600 kHz.

21. The sensor system of claim 15, wherein said sensor element comprises a magnetoelastic alloy.

22. The sensor system of claim 21, wherein said magnetoelastic alloy comprises a material selected from the group consisting of iron, cobalt, samarium, yttrium, gadolinium, terbium and dysprosium.

23. The sensor system of claim 21, wherein said magnetoelastic alloy comprises an iron based, amorphous metallic glass alloy.

24. The sensor system of claim 23, wherein said iron based, amorphous metallic glass alloy comprises Metglas™

2826.

25. The sensor system of claim 15, wherein said sensor element has a length in the range of approximately 3-5 mm, a width in the range of approximately 1-2 mm, and a thickness in the range of approximately 1-100 μ

m.

26. The sensor system of claim 15, wherein said environmental condition comprises temperature.

27. The sensor system of claim 15, wherein said sensor element is coated with a moisture sensitive material.

28. The sensor system of claim 27, wherein said moisture sensitive material exhibits a change in mass in response to a change in a second environmental condition.

29. The sensor system of claim 28, wherein said second environmental condition comprises humidity.

30. The sensor system of claim 27, wherein said moisture sensitive material comprises a metallic oxide.

31. The sensor system of claim 27, wherein said moisture sensitive material comprises a polymeric material.

32. A sensor system for sensing an environmental condition in a containment structure, comprising:

a sensor element having a first resonant frequency, said sensor element being adapted to generate said first resonant frequency in response to a first AC magnetic pulse, said sensor element comprising a material that is responsive to at least one environmental condition;

a holder having a sensor chamber therein adapted to receive said sensor element, said holder including a substantially microporous section adapted to facilitate the ingress of said environmental condition into said sensor chamber;

an interrogation device adapted to provide at least said first AC magnetic pulse to said sensor element and a second AC magnetic pulse to said containment structure; and

signal processing means for determining a value reflective of said environmental condition, said signal processing means including a receiver and a processor, said receiver being adapted to receive at least a first sensor signal corresponding to said first resonant frequency and a reference signal from said containment structure, said reference signal being generated by said containment structure in response to said second AC magnetic pulse, and communicate said first sensor signal and reference signal to said processor,

said processor being adapted to receive said first sensor signal and said reference signal, determine a first resonant frequency value from said first sensor signal and a reference signal value from said reference signal, determine a second resonant frequency value by subtracting said reference signal value from said first resonant frequency value, perform a Fourier transformation using said second resonant frequency value to determine a third resonant frequency value, and determine at least one environmental condition value from said third resonant frequency value.

33. The sensor system of claim 32, wherein said interrogation device provides a first plurality of said first AC magnetic pulses and said sensor element generates a plurality of first resonant frequency signals in response to said first AC magnetic pulses.

34. The sensor system of claim 33, wherein said processor is adapted to determine a fourth resonant frequency value for each of said fourth resonant frequency signals and determine a fifth resonant frequency value by pre-correlating said fourth resonant frequency values.

35. The sensor system of claim 34, wherein said processor is further adapted to determine said second resonant frequency value by subtracting said reference signal value from said fifth resonant frequency value.

36. The sensor system of claim 32, wherein said sensor element comprises a magnetoelastic alloy.

37. The sensor system of claim 36, wherein said magnetoelastic alloy comprises a material selected from the group consisting of iron, cobalt, samarium, yttrium, gadolinium, terbium and dysprosium.

38. The sensor system of claim 36, wherein said magnetoelastic alloy comprises an iron based, amorphous metallic glass alloy.

39. The sensor system of claim 38, wherein said iron based, amorphous metallic glass alloy comprises Metglass™

2826.

40. The sensor system of claim 32, wherein said sensor element has a length in the range of approximately 3-5 mm, a width in the range of approximately 1-2 mm, and a thickness in the range of approximately 1-100 μ

m.

41. The sensor system of claim 40, wherein said sensor element has a length of approximately 4 mm, a width of approximately 1.5 mm, and a thickness of approximately 2 μ

m.

42. The sensor system of claim 32, wherein said environmental condition comprises temperature.

43. The sensor system of claim 32, wherein said sensor element is coated with a moisture sensitive material.

44. The sensor system of claim 43, wherein said moisture sensitive material exhibits a change in mass in response to a change in a second environmental condition.

45. The sensor system of claim 44, wherein said second environmental condition comprises humidity.

46. The sensor system of claim 43, wherein said moisture sensitive material comprises a metallic oxide.

47. The sensor system of claim 43, wherein said moisture sensitive material comprises a polymeric material.

48. The sensor system of claim 47, wherein said moisture sensitive material comprises a polysilsesquioxane.

49. The sensor system of claim 48, wherein said polysilsesquioxane comprises 1,4-phenyl-bridged polysilsesquioxane.

50. The sensor system of claim 43, wherein the surface area of said coating is greater than approximately 450 m²/g.

51. The sensor system of claim 50, wherein the thickness of said coating is in the range of approximately 0. 1 μ

m-1 mm.

52. The sensor system of claim 32, wherein said holder is constructed out of a polymeric material.

53. The sensor system of claim 32, wherein said microporous section comprises a plurality of pores having a diameter in the range of 5-10 μ

m.

54. The sensor system of claim 32, wherein said microporous section comprises a lid adapted to engage said holder.

55. The sensor system of claim 54, wherein said lid includes a plurality of pores having a diameter in the range of approximately 5-10 μ

m.

56. The sensor system of claim 54, wherein said engaged holder and lid have a maximum length in the range of approximately 1.6-5.6 mm, a maximum width in the range of 2-8 mm, and a maximum height in the range of approximately 0.5-2.5 mm.

57. The sensor system of claim 32, wherein said containment structure comprises pharmaceutical packaging.

58. A packaging assembly for sensing an environmental condition within pharmaceutical packaging, comprising:

a base sheet having at least one pocket formed therein;

a lid sheet, said lid sheet including a pocket portion, said pocket portion being disposed proximate said pocket when said lid sheet is bonded to said base sheet; and

a sensor element comprising a material that is responsive to said environmental condition and having a magnetoelastic resonant frequency in the range of 300-700 kHz, said sensor element generating at least a first acoustic signal at said resonant frequency in response to an AC magnetic pulse, said sensor element being attached to said pocket portion of said lid sheet.

59. The packaging assembly of claim 58, wherein said sensor element includes first and second ends.

60. The packaging assembly of claim 59, wherein said first end of said sensor element is attached to said lid sheet pocket portion.

61. The packaging assembly of claim 58, wherein said sensor element includes a support adapted to engage said lid sheet pocket portion.

62. The packaging assembly of claim 61, wherein said first end of said sensor element is secured to said support whereby said second end of said sensor element is cantilevered.

63. The packaging assembly of claim 58, wherein said assembly includes an interrogation coil adapted to provide said AC magnetic pulse to said sensor element to generate said first acoustic signal.

64. The packaging assembly of claim 58, wherein said assembly further includes a receiver adapted to detect said first acoustic signal.

65. The packaging assembly of claim 58, wherein said sensor element comprises a magnetoelastic alloy.

66. The packaging assembly of claim 65, wherein said magnetoelastic alloy comprises a material selected from the group consisting of iron, cobalt, samarium, yttrium, gadolinium, terbium and dysprosium.

67. The packaging assembly of claim 65, wherein said magnetoelastic alloy comprises an iron based, amorphous metallic glass alloy.

68. The packaging assembly of claim 67, wherein said iron based, amorphous metallic glass alloy comprises Metglass™

2826.

69. The packaging assembly of claim 58, wherein said environmental condition comprises temperature.

70. The packaging assembly of claim 58, wherein said sensor element is coated with a moisture sensitive material.

71. The packaging assembly of claim 70, wherein said moisture sensitive material exhibits a change in mass in response to a change in a second environmental condition.

72. The packaging assembly of claim 71, wherein said second environmental conditions comprises humidity.

73. The packaging assembly of claim 70, wherein said moisture sensitive material comprises 1,4-phenyl-bridged polysilsesquioxane.

74. The packaging assembly of claim 58, wherein said packaging assembly further includes a memory adapted to receive and store at least said first acoustic signal, a processor for determining at least a first environmental condition value using said first acoustic signal, and a display.

75. A method of sensing an environmental condition in a containment structure, comprising the steps of:

providing a containment structure;

providing a sensor system, said sensor system comprising a sensor element, an interrogation device, a receiver and a processor, said sensor element being responsive to at least one environmental condition and having a first resonant frequency;

providing at least a first AC magnetic pulse to said containment structure, said containment structure generating a reference signal in response to said first AC magnetic pulse;

providing at least a second AC magnetic pulse to said sensor element, said sensor element generating a first resonant frequency signal in response to said second AC magnetic pulse;

detecting said reference signal and said first resonant frequency signal;

determining a first resonant frequency value from said first resonant frequency signal and a reference signal value from said reference signal;

determining a second resonant frequency value by subtracting said reference signal value from said first resonant frequency value;

determining a third resonant frequency value by performing a Fourier transformation using said second resonant frequency value; and

determining at least one environmental condition value from said third resonant frequency value.

76. The method of claim 75, wherein said containment structure comprises pharmaceutical packaging.

77. A method of sensing an environmental condition in a containment structure, comprising the steps of:

providing a containment structure;

providing a sensor system, said sensor system comprising a sensor element, an interrogation device, a receiver and a processor, said sensor element being responsive to at least one environmental condition and having a first resonant frequency;

providing at least a first AC magnetic pulse to said containment structure, said containment structure generating a reference signal in response to said first AC magnetic pulse;

providing a plurality of second AC magnetic pulses to said sensor element, said sensor element generating a plurality of first resonant frequency signals in response to said second AC magnetic pulse;

determining a reference signal value from said reference signal;

determining a first resonant frequency value for each of said first resonant frequency signal;

determining a second resonant frequency value by pre-correlating said first resonant frequency values;

determining a third resonant frequency value by subtracting said reference signal value from said second resonant frequency value;

determining a fourth resonant frequency value by performing a Fourier transformation using said third resonant frequency value; and

determining at least one environmental condition value from said fourth resonant frequency value.

78. The method of claim 77, wherein said containment structure comprises pharmaceutical packaging.