High noise suppression microphone

• US 6,347,147 B1
• Filed: 12/07/1998
• Issued: 02/12/2002
• Est. Priority Date: 12/07/1998
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Downs, Edward F. Jr., Venturella, Kevin M.
• Primary Examiner(s): Harvey, Minsun Oh
• Application Number:
  US09/207,903
• Time in Patent Office: 1,163 Days
• Field of Search: 381/114, 381/173, 381/71.1, 381/190, 340/384.6, 340/384.73, 310/326, 310/327, 310/328
• US Class Current: 381/114
• CPC Class Codes: H04R 17/02 Microphones

Abstract

A noise suppressing microphone employing a thin film of piezoelectric material sandwiched between two conductive layers, one of which is laminated to a flat inflexible laminate. The sandwich is embedded in a mechanical sound filter except for one exposed face which is placed in contact with a user'"'"'s body for sound pickup. The filter is composed of sound dissipating material, alone or in complementary configurations, and in sandwiches including a sound absorbing and sound reflecting metal layer, or a pillow of mastic-like sound-deadening material

Claims

1. A high-noise suppression microphone, comprising:

a. A film of piezoelectric material having two opposite faces,

b. Two thin films of conductive material, one of said films of conductive material being affixed to one of said two opposite faces and another of said films of conductive material being affixed to another of said two opposite faces, thereby forming a piezoelectric sandwich element with the thin film of piezoelectric material in between the two thin films of conductive material such that a first face of the piezoelectric sandwich element is defined by said one of said films of conductive material and such that a second face of the piezoelectric sandwich element is defined by said another of said films of conductive material,

c. A flat, substantially inflexible substrate laminated to the piezoelectric sandwich element along substantially the entire surface of the first face of the piezoelectric sandwich element,

d. Two connecting conductors connected to the two films of conductive material for carrying an electrical signal between the piezoelectric sandwich element and some external point, and

e. An ambient noise filter embedding the piezoelectric sandwich element and inflexible substrate except for the second face of the piezoelectric sandwich element for substantially preventing sound impinging on the noise filter from reaching the film of piezoelectric material.

2. The microphone of claim 1 wherein said noise filter is one layer of noise suppresion material.

3. The microphone of claim 1 wherein said noise filter is a multi-layer arrangement of materials.

4. The microphone of claim 3 wherein the multi-layer arrangement includes sound reflective and sound absorptive material layers.

5. The microphone of claim 4 wherein each sound reflective material layer is a metal.

6. The microphone of claim 4 wherein each sound absorptive material layer is a non-metal composite.

7. The microphone of claim 3 wherein each layer of the multi-layer arrangement is of elastic and non-metal composition.

8. The microphone of claim 5 wherein each sound reflective material layer is sandwiched between two of the sound absorptive material layers.

9. The microphone of claim 1 wherein the noise filter consists of a first and second composite layer, each said first and second composite layer comprising a layer of high-density rubber-like material laminated to a layer of foam decoupler, said first and second composite layers bonded together such that the high-density layer of said first composite layer is in contact with the foam decoupler layer of said second composite layer.

10. The microphone of claim 9 wherein a metal sheet is bonded in between said first and second composite layer such that the high-density side of said first composite layer is in contact with one side of said metal sheet and the foam decoupler side of said second composite layer is in contact with the opposite side of said metal sheet.

11. The microphone of claim 10 further comprising a ground shield interposed between the noise filter and the piezoelectric sandwich element to protect the piezoelectric sandwich element from electromagnetic interference.

12. The microphone of claim 1 further comprising a water-resistant protection layer encasing the combination of the piezoelectric sandwich element and the inflexible substrate laminated thereto for protection of the piezoelectric sandwich element against environment moisture.

13. The microphone of claim 3 wherein the multi-layer arrangement is two layers of sound absorbing material sandwiched about a layer comprising a pillow of mastic-like sound deadening material.