Spiral wound transducer

• US 6,420,814 B1
• Filed: 05/18/1999
• Issued: 07/16/2002
• Est. Priority Date: 05/18/1999
• Status: Expired due to Fees

• Current Assignee: University North Carolina-Charlotte
• Original Assignee: University North Carolina-Charlotte
• Inventors: Bobbio, Stephen M.
• Primary Examiner(s): Ramirez, Nestor
• Assistant Examiner(s): Perez, Guillermo
• Application Number:
  US09/314,798
• Time in Patent Office: 1,155 Days
• Field of Search: 310/309, 310/308, 200/181, 322/2.A, 318/116, 324/457
• US Class Current: 310/309
• CPC Class Codes: H02N 1/006 of the gap-closing type H02N1/004 takes precedence

Abstract

A transducer compressible in response to electric power, including a flexible, conductive plastic layer microimprinted with a pattern and a stiff plastic layer containing a conductive embedded sheet.

Claims

1. A transducer compressible in a portion of the transducer in response to electric power, comprising:

(a) a flexible, conductive plastic layer microimprinted with a tread-like pattern; and

(b) a stiff plastic layer containing a conductive embedded sheet, wherein the flexible layer and the stiff layer are formed by multiply winding together around a central form, so that the microimprinted flexible layer is bounded by stiff layers,

wherein compression of the transducer in the compressed portion of the transducer is perpendicular to the plane of the conductive embedded sheet and to the linear axis of the central form, and wherein the flexible layer is distorted during compression of the transducer while the stiff layer remains parallel to the surface of the central form in the compressed portion of the transducer.

2. The transducer of claim 1, wherein the flexible layer comprises metallized polyimide.

3. The transducer of claim 1, wherein the flexible layer is conductive due to being made of a conductive plastic material.

4. The transducer of claim 1, wherein the flexible layer is conductive due to a thin metal coating.

5. The transducer of claim 1, wherein the conductive embedded sheet comprises a thin metal film.

6. The transducer of claim 5, wherein the thin metal film is 200 Angstroms chromium and 2000 Angstroms gold.

7. The transducer of claim 1, wherein the layers are in the form of strips formed on a substrate suitable for microelectronic processing.

8. The transducer of claim 7, wherein the substrate is a silicon wafer.

9. The transducer of claim 1, wherein the layers comprise silicon oxide on a silicon wafer, over which a first polyimide layer has been coated and cured and a metal has been evaporated and patterned, and a second polyimide layer has been coated and cured and a hard mask applied and patterned.

10. The transducer of claim 9, further comprising performing an oxygen plasma etch.

11. A transducer compressible in a portion of the transducer in response to electric power, comprising:

(a) a flexible, conductive plastic layer; and

(b) a stiff plastic layer containing a conductive embedded sheet, wherein the flexible layer and the stiff layer are composed as a single inseparable unit, and then formed by multiply winding together around a central form and bonding each turn of the winding to adjacent turns by application of an adhesive in the compressed portion of the transducer, wherein compression of the transducer in the compressed portion is perpendicular to the plane of the conductive embedded sheet and to the linear axis of the central form, and wherein compression of an area of the transducer results in distortion of the flexible layer while the stiff layer remains parallel to the surface of the central form in the compressed portion of the transducer.

12. The transducer of claim 11, wherein the transducer comprises two stiff layers with the flexible layer being between the two stiff layers.

13. The transducer of claim 11, wherein the layers are bound into the single inseparable unit before winding by use of a patternable microadhesive.

14. The transducer of claim 13, wherein the microadhesive comprises a diazoquinone novolak photoresist that has been applied to a layer, following by patterning, exposure with UV light, treatment with a plasticizer, and contact with a second layer, heating and joining to the second layer.

15. The transducer of claim 11, wherein the layers are bound into a single inseparable unit by reheating an embossing powder.

16. The transducer of claim 11, wherein the layers are bound into a single inseparable unit by fabricating the stiff and microimprinted layers directly.