Ultrasonic transducer for parametric array

• US 20030091200A1
• Filed: 10/09/2002
• Published: 05/15/2003
• Est. Priority Date: 10/09/2001
• Status: Active Grant

• Current Assignee: Frank Joseph Pompei
• Original Assignee: Frank Joseph Pompei
• Inventors: Pompei, Frank Joseph
• Granted Patent: US 6,771,785 B2
• Time in Patent Office: Days
• US Class Current: 381/77
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type
• CPC Class Codes: B06B 1/0622 on one surface
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H04R 19/02 Loudspeakers H04R19/01 takes precedence
• CPC Class Codes: H04R 31/00 Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor manufacture of microstructural arrangements of deformable or non-deformable structures in general B81C1/00182

Abstract

An ultrasonic transducer having a reduced cost of manufacture. The ultrasonic transducer includes a first insulative retaining layer, a second insulative retaining layer, and a vibrator film layer sandwiched between the first and second retaining layers. The first retaining layer includes a first plurality of apertures formed therethrough, and the second retaining layer includes a second plurality of apertures formed therethrough, in which the second apertures are substantially in registration with the first apertures. The ultrasonic transducer further includes a first cover portion having a plurality of spring/backplate assemblies connected thereto, and a second cover portion. The combination of the first retaining layer, the vibrator film layer, and the second retaining layer is sandwiched between the first and second cover portions of the ultrasonic transducer. The laminated construction of the ultrasonic transducer allows the formation of an array of ultrasonic film transducers using a single piece of ultrasonic vibrator film.

Claims

1. An electrostatic acoustic transducer, comprising:

a first electrode;

a first retaining layer having a plurality of first apertures formed therethrough;

a vibrator film layer disposed between the first electrode and the first retaining layer;

a plurality of plates disposed between the first electrode and the vibrator film layer, each plate being substantially in registration with a respective one of the first apertures formed through the first retaining layer;

at least one resilient member disposed between the first electrode and the plurality of plates, the resilient member being configured to urge the respective plates against the vibrator film layer; and

a second electrode disposed on one side of the adjacent first retaining layer,

wherein the transducer is configured to receive a drive voltage across the first and second electrodes for vibrating the film layer, thereby generating a series of compression waves at sonic or ultrasonic frequencies.

2. The transducer of claim 1 wherein the vibrator film layer comprises a single piece of film.

3. The transducer of claim 1 wherein the vibrator film layer has a conductive side facing the first retaining layer and a nonconductive side facing the first electrode, the conductive side of the vibrator film layer being configured to form the second electrode.

4. The transducer of claim 3 wherein the conductive side of the vibrator film layer comprises aluminum, gold, or nickel.

5. The transducer of claim 1 wherein the vibrator film layer is made of a polymer.

6. The transducer of claim 5 wherein the polymer is selected from the group consisting of polyester, polyimide, PVDF, PET, and PTFE.

7. The transducer of claim 1 wherein the vibrator film layer has a thickness ranging from 0.2 μ

m to 100.0 μ

m.

8. The transducer of claim 1 further including a second retaining layer having a plurality of second apertures formed therethrough, the second retaining layer being disposed between the vibrator film layer and the first electrode, each second aperture being substantially in registration with a respective one of the first apertures, the plurality of plates being substantially disposed within the respective second apertures.

9. The transducer of claim 8 wherein the second retaining layer has a labyrinth channel formed therein, the labyrinth channel being configured to provide cable strain relief, the transducer further including a cable disposed in the labyrinth channel and configured to provide the drive voltage across the first and second electrodes.

10. The transducer of claim 9 wherein the cable comprises a shielded cable.

11. The transducer of claim 1 further including a protective layer disposed on one side of the first retaining layer opposite the vibrator film layer.

12. The transducer of claim 11 wherein the protective layer and the vibrator film layer are spaced apart a predetermined distance sufficient to minimize sonic absorption due to the protective layer.

13. The transducer of claim 12 wherein the predetermined distance corresponds to a thickness of the first retaining layer.

14. The transducer of claim 12 wherein the predetermined distance is about ½

of the wavelength of the sonic or ultrasonic wave.

15. The transducer of claim 11 wherein the protective layer is connected to ground potential.

16. The transducer of claim 1 wherein the resilient member is electrically connected to the first electrode and the respective plates.

17. The transducer of claim 1 further including a shielded cable configured to provide the drive voltage across the first and second electrodes.

18. An ultrasonic transducer, comprising:

a vibrator surface; and

a protective cover disposed on one side of the vibrator surface,

wherein the protective cover and the vibrator surface are spaced apart a predetermined distance sufficient to minimize sonic absorption due to the protective cover.

19. The transducer of claim 18 further including a retaining layer disposed between the vibrator surface and the protective cover, and wherein the predetermined distance corresponds to a thickness of the retaining layer.

20. The transducer of claim 18 wherein the predetermined distance is about ½

of the wavelength of a sonic or ultrasonic wave generated by the ultrasonic transducer.

21. The transducer of claim 18 further including an ornamental layer attached substantially around the protective layer and the vibrator surface.

22. The transducer of claim 21 wherein the ornamental layer comprises a fabric cover.

23. The transducer of claim 18 wherein the protective cover is connected to ground potential.

24. A parametric loudspeaker, comprising:

at least one audio signal source configured to provide at least one audio signal;

a modulator configured to receive a first signal representative of the audio signal and to convert the first signal into ultrasonic frequencies; and

an ultrasonic transducer having a vibrator surface and a protective cover disposed on one side of the vibrator surface,

wherein the protective cover and the vibrator surface are spaced apart a predetermined distance sufficient to minimize sonic absorption due to the protective cover.

25. The parametric loudspeaker of claim 24 further including a retaining layer disposed between the vibrator surface and the protective cover, and wherein the predetermined distance corresponds to a thickness of the retaining layer.

26. The parametric loudspeaker of claim 24 wherein the predetermined distance is about ½

of the wavelength of a sonic or ultrasonic wave generated by the ultrasonic transducer.

27. The parametric loudspeaker of claim 24 further including an ornamental layer attached substantially around the protective layer and the vibrator surface.

28. The parametric loudspeaker of claim 27 wherein the ornamental layer comprises a fabric cover.

29. The parametric loudspeaker of claim 24 wherein the protective cover is connected to ground potential.

30. A parametric audio system, comprising:

at least one audio signal source configured to provide at least one audio signal;

a modulator configured to receive a first signal representative of the audio signal and to convert the first signal into ultrasonic frequencies; and

an electrostatic acoustic transducer configured to receive the converted first signal and to project the converted first signal through the air along a selected path, thereby regenerating the audio signal along at least a portion of the selected path,

wherein the electrostatic acoustic transducer includes a first electrode,

a first retaining layer having a plurality of first apertures formed therethrough,

a vibrator film layer disposed between the first electrode and the first retaining layer,

a plurality of plates disposed between the first electrode and the vibrator film layer, each plate being substantially in registration with a respective one of the first apertures formed through the first retaining layer,

at least one resilient member disposed between the first electrode and the plurality of plates, the resilient member being configured to urge the respective plates against the vibrator film layer, and

a second electrode disposed on one side of the adjacent first retaining layer,

wherein the transducer is configured to receive a drive voltage across the first and second electrodes for vibrating the film layer, thereby generating the projected signal.

31. The parametric audio system of claim 30 wherein the vibrator film layer comprises a single piece of film.

32. The parametric audio system of claim 30 wherein the vibrator film layer has a conductive side facing the first retaining layer and an nonconductive side facing the first electrode, the conductive side of the vibrator film layer being configured to form the second electrode.

33. The parametric audio system of claim 32 wherein the conductive side of the vibrator film layer comprises aluminum, gold, or nickel.

34. The parametric audio system of claim 30 wherein the vibrator film layer is made of a polymer.

35. The parametric audio system of claim 34 wherein the polymer is selected from the group consisting of polyester, polyimide, PVDF, PET, and PTFE.

36. The parametric audio system of claim 30 wherein the vibrator film layer has a thickness ranging from 0.2 μ

m to 100.0 μ

m.

37. The parametric audio system of claim 30 further including a second retaining layer having a plurality of second apertures formed therethrough, the second retaining layer being disposed between the vibrator film layer and the first electrode, each second aperture being substantially in registration with a respective one of the first apertures, the plurality of plates being substantially disposed within the respective second apertures.

38. The parametric audio system of claim 37 wherein the second retaining layer has a labyrinth channel formed therein, the labyrinth channel being configured to provide cable strain relief, the transducer further including a cable disposed in the labyrinth channel and configured to provide the drive voltage across the first and second electrodes.

39. The parametric audio system of claim 38 wherein the cable comprises a shielded cable.

40. The parametric audio system of claim 30 further including a protective layer disposed on one side of the first retaining layer opposite the vibrator film layer.

41. The parametric audio system of claim 40 wherein the protective layer and the vibrator film layer are spaced apart a predetermined distance sufficient to minimize sonic absorption due to the protective layer.

42. The parametric audio system of claim 41 wherein the predetermined distance corresponds to a thickness of the first retaining layer.

43. The parametric audio system of claim 41 wherein the predetermined distance is about ½

of the wavelength of the sonic or ultrasonic wave.

44. The parametric audio system of claim 40 wherein the protective layer is connected to ground potential.

45. The parametric audio system of claim 30 wherein the resilient member is electrically connected to the first electrode and the respective plates.

46. An acoustic sound generator, comprising:

at least one audio signal source configured to provide at least one audio signal; and

an electrostatic acoustic transducer configured to receive the audio signal and to project the audio signal through the air,

wherein the electrostatic acoustic transducer includes

a first electrode,

a first retaining layer having a plurality of first apertures formed therethrough,

a vibrator film layer disposed between the first electrode and the first retaining layer,

a plurality of plates disposed between the first electrode and the vibrator film layer, each plate being substantially in registration with a respective one of the first apertures formed through the first retaining layer,

at least one resilient member disposed between the first electrode and the plurality of plates, the resilient member being configured to urge the respective plates against the vibrator film layer, and

a second electrode disposed on one side of the adjacent first retaining layer,

wherein the transducer is configured to receive a drive voltage across the first and second electrodes for vibrating the film layer, thereby generating the projected signal.

47. The acoustic sound generator of claim 46 wherein the vibrator film layer comprises a single piece of film.

48. The acoustic sound generator of claim 46 wherein the vibrator film layer has a conductive side facing the first retaining layer and a nonconductive side facing the first electrode, the conductive side of the vibrator film layer being configured to form the second electrode.

49. The acoustic sound generator of claim 48 wherein the conductive side of the vibrator film layer comprises aluminum, gold, or nickel.

50. The acoustic sound generator of claim 46 wherein the vibrator film layer is made of a polymer.

51. The acoustic sound generator of claim 50 wherein the polymer is selected from the group consisting of polyester, polyimide, PVDF, PET, and PTFE.

52. The acoustic sound generator of claim 46 wherein the vibrator film layer has a thickness ranging from 0.2 μ

m to 100.0 μ

m.

53. The acoustic sound generator of claim 46 wherein the resilient member is electrically connected to the first electrode and the respective plates.

54. The acoustic sound generator of claim 46 further including a second retaining layer having a plurality of second apertures formed therethrough, the second retaining layer being disposed between the vibrator film layer and the first electrode, each second aperture being substantially in registration with a respective one of the first apertures, the plurality of plates being substantially disposed within the respective second apertures.

55. The acoustic sound generator of claim 54 wherein the second retaining layer has a labyrinth channel formed therein, the labyrinth channel being configured to provide cable strain relief, the transducer further including a cable disposed in the labyrinth channel and configured to provide the drive voltage across the first and second electrodes.

56. The acoustic sound generator of claim 55 wherein the cable comprises a shielded cable.

57. The acoustic sound generator of claim 46 further including a protective layer disposed on one side of the first retaining layer opposite the vibrator film layer.

58. The acoustic sound generator of claim 57 wherein the protective layer and the vibrator film layer are spaced apart a predetermined distance sufficient to minimize sonic absorption due to the protective layer.

59. The acoustic sound generator of claim 58 wherein the predetermined distance corresponds to a thickness of the first retaining layer.

60. The acoustic sound generator of claim 58 wherein the predetermined distance is about ½

of the wavelength of the sonic or ultrasonic wave.

61. The acoustic sound generator of claim 57 wherein the protective layer is connected to ground potential.

62. An electrostatic acoustic transducer, comprising:

a first electrode;

a first retaining layer having at least one first aperture formed therethrough;

a vibrator film layer disposed between the first electrode and the first retaining layer;

at least one plate disposed between the first electrode and the vibrator film layer, the plate being substantially in registration with the first aperture formed through the first retaining layer;

at least one resilient member disposed between the first electrode and the plate, the resilient member being configured to urge the plate against the vibrator film layer; and

a second electrode disposed on one side of the adjacent first retaining layer;

wherein the transducer is configured to receive a drive voltage across the first and second electrodes for vibrating the film layer, thereby generating an output comprising a series of compression waves at sonic or ultrasonic frequencies,

the transducer further including a bias circuit configured to generate a DC bias signal for amplifying the transducer output.

63. The transducer of claim 62 wherein the bias circuit is configured to be powered by a DC drive signal.

64. The transducer of claim 62 wherein the bias circuit is configured to be powered by an AC drive signal.

65. The transducer of claim 62 further including a second retaining layer having at least one second aperture formed therethrough, the second retaining layer being disposed between the vibrator film layer and the first electrode, the second aperture being substantially in registration with the first aperture formed through the first retaining layer, the plate being substantially disposed within the second aperture.

66. The transducer of claim 62 wherein the resilient member is electrically connected to the first electrode and the respective plates.

67. A method of manufacturing an electrostatic acoustic transducer, comprising the steps of:

laminating a vibrator film layer between a first retaining layer and a second retaining layer, the first retaining layer having a plurality of first apertures formed therethrough, the second retaining layer having a plurality of second apertures formed therethrough, the first apertures being substantially in registration with the respective second apertures;

disposing a respective plate member substantially within the first apertures formed through the first retaining layer;

disposing a respective resilient member on the plate member, the resilient member being configured to urge the respective plate member against the vibrator film layer; and

attaching a cover portion to at least the adjacent first retaining layer to compress the resilient member against the respective plate member.

68. The method of claim 67 further including the step of disposing a protective layer near the adjacent second retaining layer.

69. The method of claim 68 wherein the third disposing step includes disposing the protective layer a predetermined distance from the vibrator film layer, the predetermined distance being sufficient to minimize sonic absorption due to the protective layer.

70. The method of claim 69 wherein the predetermined distance corresponds to a thickness of the second retaining layer.

71. The method of claim 69 wherein the predetermined distance is about ½

of the wavelength of a sonic or ultrasonic wave generated by the transducer.

72. The method of claim 68 further including the step of connecting the protective layer to ground potential.

73. The method of claim 67 further including the step of attaching an ornamental layer substantially around the protective layer and the first and second retaining layers.

74. The method of claim 67 wherein the ornamental layer comprises a fabric cover.