Musical instrument transducer assembly having a piezoelectric sheet

• US 5,319,153 A
• Filed: 05/21/1992
• Issued: 06/07/1994
• Est. Priority Date: 04/28/1986
• Status: Expired due to Term

• Current Assignee: Fishman Transducers Incorporated
• Original Assignee: Lawrence R. Fishman
• Inventors: Fishman, Lawrence
• Primary Examiner(s): Witkowski, Stanley J.
• Application Number:
  US07/887,175
• Time in Patent Office: 747 Days
• Field of Search: 84/723-743, 84/DIG. 24, 310/340, 310/342, 310/344, 310/365-371
• US Class Current: 84/731
• CPC Class Codes: G10H 2220/471 at bottom, i.e. transducer positioned at the bottom of the bridge, between the bridge and the body of the instrument
• CPC Class Codes: G10H 2220/485 One transducer per string, e.g. 6 transducers for a 6 string guitar
• CPC Class Codes: G10H 2220/495 Single bridge transducer, common to all strings
• CPC Class Codes: G10H 2220/531 made of piezoelectric film
• CPC Class Codes: G10H 2220/535 Piezoelectric polymer transducers, e.g. made of stretched and poled polyvinylidene difluoride [PVDF] sheets in which the molecular chains of vinylidene fluoride CH2-CF2 have been oriented in a preferential direction
• CPC Class Codes: G10H 3/185 in which the tones are picked up through the bridge structure
• CPC Class Codes: Y10S 84/24 Piezoelectrical transducers

Abstract

A musical instrument transducer module encloses a piezoelectric transducer, preferably comprising a polyvinylidene fluoride co-polymer sheet, and has an elongated electrically conductive member and a conductive shield. The shield forms a U-shaped channel and the elongated member extends from the shield. The conductive member can be moved by rotation into the shield. The conductive member covers one side of the piezoelectric transducer, and another conductor covers at least part of the other side of the transducer. An electrical lead has contacts to both conductors on either side of the transducer. The transducer can include one or more sheets.

Claims

1. A module for fabricating a stringed instrument transducer, said module adapted to be positioned adjacent the instrument strings to receive acoustic vibratory signals therefrom, said module comprising;

a first elongated electrically conductive member,

a means for conductively shielding the first conductive member, said shield means integral with the first conductive member, said first conductive member having a conductive tailpiece, the tailpiece adapted to receive a second elongated electrically conductive member and a piezoelectric transducer comprising a polyvinylidene fluoride co-polymer, said second conductive member and transducer positioned on the tailpiece to form an elongated unitary structure that includes said piezoelectric transducer disposed between said conductive tailpiece and said second electrically conductive member, said tailpiece adapted for rotational movement about a junction between a first position where the unitary structure is disposed outside the shield means, and a second position where the unitary structure is disposed inside the shield means;

means for electrically contacting the shield means and one of said first and second electrically conductive members.

2. A module of claim 1, wherein the piezoelectric transducer comprises a plurality of piezoelectric transducers, each adapted to be aligned with an instrument string and spacedly disposed along the tailpiece so as to be in alignment with respective strings when the tailpiece is in the second position.

3. The module of claim 1, wherein said piezoelectric transducer is of elongated and substantially flat form, the transducer adapted to be aligned with a plurality of instrument strings when the tailpiece is in the second position.

4. The module of claim 3, wherein the piezoelectric transducer includes a laminate comprising a plurality of elongated and substantially flat piezoelectric transducers.

5. The module of claim 1, further comprising a means for shielding said elongated unitary structure comprising a plastic layer disposed around the unitary structure.

6. The module of claim 5, wherein the plastic layer is Mylar.

7. The module of claim 1, wherein the polyvinylidene fluoride co-polymer has a degree of crystallinity greater than about 70%.

8. The module of claim 1, wherein said piezoelectric transducer has a total thickness of about 50 to about 1000 microns.

9. The module of claim 4, wherein the laminate of piezoelectric transducers has a total thickness of about 500 microns.

10. The module of claim 9, wherein each of said plurality of piezoelectric transducers is about equal in thickness.

11. The module of claim 1, wherein said means for electrically contacting comprises electrical lead means connected to said first and second electrically conductive members.

12. The module of claim 2, further comprising conductive adhesive means for securing one of said second elongated electrically conductive member or said first electrically conductive member to said piezoelectric transducer, said transducer being adhered so as to stress the piezoelectric transducer and thus increase voltage therefrom, at least a major portion of said piezoelectric transducer being adhered to provide the stressing.

13. The module of claims 1 or 12, wherein said second elongated electrically conductive member comprises a conductive strip adjacent said piezoelectric transducer and a resilient and electrically conductive layer disposed between said piezoelectric transducer and said conductive strip.

14. The module of claim 11, wherein said electrical lead means is connected to said second elongated electrically conductive member when said conductive tailpiece is in the second position, said connection accomplished through a hole defined in said second electrically conductive member.

15. A module for enclosing a stringed instrument transducer, said module constructed to be positioned under a saddle of said instrument for coupling vibratory action from instrument strings via the saddle to said transducer, said module comprising;

a first electrically conductive member;

a means for conductively shielding the first electrically conductive member that is integral with the first electrically conductive member, said first electrically conductive member including a conductive element, the conductive element arranged to receive a second electrically conductive member and a piezoelectric transducer, said second electrically conductive member and said piezoelectric transducer positioned on the conductive element to form a unitary structure,

wherein said conductive element is adapted for rotational movement between a first position, where the unitary structure is disposed outside the shield means, and a second position, where the unitary structure is disposed inside the shield means.

16. The module of claim 15, wherein said piezoelectric transducer having one and another sides, said conductive element positioned on said one side of said piezoelectric transducer and receiving the one side of the transducer in electrically coupling contact therewith, said second electrically conductive member positioned at said other side of said piezoelectric transducer.

17. The module of claim 15, further comprising conductive adhesive means for securing either the one side or the other side of the piezoelectric transducer to the conductive element or the second electrically conductive member, respectively, the transducer being secured so as to stress the piezoelectric transducer and thus increase voltage therefrom, at least a major portion of said transducer being bonded to provide the stressing.

18. The module of claim 15, further comprising means for shielding the unitary structure disposed about said module comprising a base dielectric layer wrapped about the unitary structure and having deposited thereon an electrically conductive layer.

19. The module of claim 15, further comprising means for electrically connecting the shield means with said first and second electrically conductive members when said conductive element is in the second position.

20. The module of claim 16, wherein said second electrically conductive member includes an electrically conductive strip positioned at the other side of said piezoelectric transducer and a resilient and electrically conductive carbon fiber layer disposed between said piezoelectric transducer and said conductive strip.

21. The module of claim 15, wherein the piezoelectric transducer comprises a plurality of transducers, each aligned with an instrument string and spacedly disposed so as to be in alignment with respective strings.

22. The module of claim 15, wherein the piezoelectric transducer is an elongated and substantially flat form, the transducer adapted to be in alignment with a plurality of instrument strings.

23. The module of claim 22, wherein the elongated and substantially flat transducer is a laminate comprising a plurality of elongated and substantially flat transducers, the laminate aligned with said conductive element and second electrically conductive member.

24. The module of claim 23, wherein said laminate has a total thickness of about 500 microns.

25. The module of claim 23, wherein each of said plurality of piezoelectric transducers is about equal in thickness.

26. The module of claim 15, 20, 21, 22 or 23, wherein said piezoelectric transducer comprises a polyvinylidene copolymer of greater than about 70% crystallinity.

27. A module for enclosing a stringed instrument transducer, said module constructed to be positioned under a saddle of said instrument for coupling vibratory action from instrument strings via the saddle to said transducer, said module comprising;

a first electrically conductive member having sides defining a substantially U-shaped channel, said first electrically conductive member including a conductive element extending outwardly from an end of said channel, the conductive element arranged to receive a second electrically conductive member and a piezoelectric transducer, said second electrically conductive member and said piezoelectric transducer positioned on the conductive element to form a unitary structure,

wherein said conductive element is adapted for rotational movement between a first position, where the unitary structure is disposed outside the channel, and a second position, where the unitary structure is disposed inside the channel.

28. The module of claim 27, further comprising a base dielectric layer surrounding said unitary structure in the first position outside the channel.

29. The module of claim 28, further comprising a base dielectric layer surrounding said unitary structure in the second position inside the channel.

30. The module of claims 28 or 29, wherein the base dielectric layer is comprised of Mylar.

31. The module of claim 27, further comprising conductive adhesive means for securing either a first side or a second side of the piezoelectric transducer to the conductive element or the second electrically conductive member, respectively, the transducer being secured so as to stress the piezoelectric transducer and thus increase voltage therefrom, at least a major portion of said transducer being bonded to provide the stressing.

32. The module of claim 27, further comprising means for electrically connecting the shield means with said first and second electrically conductive members when said conductive element is in the second position.

33. The module of claim 27, wherein said second electrically conductive member includes an electrically conductive strip positioned at the second side of said piezoelectric transducer and a resilient and electrically conductive carbon fiber layer disposed between said piezoelectric transducer and said conductive strip.

34. The module of claim 27, wherein the piezoelectric transducer comprises a plurality of transducers, each aligned with an instrument string and spacedly disposed so as to be in alignment with respective strings.

35. The module of claim 27, wherein the piezoelectric transducer is an elongated and substantially flat form, the transducer adapted to be in alignment with a plurality of instrument strings.

36. The module of claim 35, wherein the elongated and substantially flat transducer is a laminate comprising a plurality of elongated and substantially flat transducers, the laminate aligned with said conductive element and second electrically conductive member.

37. The module of claim 27 or 36, wherein said piezoelectric transducer comprises a polyvinylidene copolymer of greater than about 70% crystallinity.

38. A transducer assembly for a stringed musical instrument comprising:

an elongated dielectric member having a conductive material on a surface;

a first elongated piezoelectric sheet having

a first surface which covers at least most of the conductive material on the surface of the dielectric member, and

a second surface;

an elongated conductive member covering at least most of the second surface, and being in electrical contact with the piezoelectric sheet; and

a conductive lead having a first contact electrically coupled to the conductive material on the surface of the dielectric member, and a second contact electrically coupled to the conductive member.

39. The transducer assembly of claim 38 wherein the piezoelectric sheet comprises a polymer.

40. The transducer assembly of claim 39 further comprising a second piezoelectric sheet having about the same dimensions as the first piezoelectric sheet and covering the first piezoelectric sheet.

41. The transducer assembly of claim 38 wherein the conductive material on the circuit board is a copper cladding.

42. The transducer assembly of claim 38 wherein the first contact of the conductive lead is soldered to the conductive material on the circuit board.

43. The transducer assembly of claim 38 wherein:

the elongated conductive member is in a first plane;

the transducer assembly further comprises a second elongated conductive member electrically coupled to the elongated conductive member and in a second plane which is parallel to the first plane; and

the second contact of the conductive lead is connected to the second elongated conductive member.

44. The transducer assembly of claim 38 wherein the piezoelectric sheet comprises a polyvinylidene copolymer.

45. A transducer assembly for a stringed musical instrument comprising:

an elongated dielectric member having a conductive material on a surface;

a first elongated piezoelectric sheet having a first surface which covers at least part of the conductive material on the surface of the dielectric material, and a second surface;

a second elongated piezoelectric sheet having a first surface which at least partially covers the second surface of the first sheet, and a second surface;

an elongated conductive member covering at least part of, and being in electrical contact with, the second piezoelectric sheet; and

a conductive lead having a first contact electrically coupled to the conductive material on the surface of the dielectric member, and a second contact electrically coupled to the conductive member.

46. The assembly of claim 45 wherein the first and second piezoelectric sheets each comprise a polyvinylidene copolymer.

47. A transducer assembly for a stringed musical instrument adapted to be positioned under the instrument saddle for coupling vibratory action from the instrument strings via the saddle to said transducer system, said transducer system comprising;

a piezoelectric transducer having one end another side;

a first electrically conductive member positioned at the one side of the transducer and receiving the one side of the transducer in electrically coupling contact;

a second electrically conductive member positioned at the other side of the transducer, the electrically conductive members and transducer positioned to form an elongated unitary structure that includes the piezoelectric transducer disposed between the first electrically conductive member and the second electrically conductive member;

conductive shield means disposed about said unitary structure;

means for providing electrical contact between the shield means and one of the first and second electrically conductive members; and

a conductive lead connected to the first and second electrically conductive members.

48. The assembly of claim 47 wherein the piezoelectric sheet comprises a polyvinylidene copolymer sheet.

49. A transducer assembly for a stringed musical instrument adapted to be positioned under the instrument saddle for coupling vibratory action from the instrument strings via the saddle to said transducer system, said transducer system comprising;

a first piezoelectric transducer having first and second sides;

a second piezoelectric transducer having first and second sides, the second side of the first transducer at least partially covering the first side of the second transducer;

a first electrically conductive member positioned to cover at least a part of the first side of the first transducer and being in electrical contact with the first transducer;

a second electrically conductive member positioned at the second side of the second transducer, the electrically conductive members and the transducers positioned to form an elongated unitary structure that includes the piezoelectric transducers disposed between the first electrically conductive member and the second electrically conductive member;

conductive shield means disposed about said unitary structure;

means for providing electrical contact between the shield means and one of the first and second electrically conductive members; and

a conductive lead connected to the first and second electrically conductive members.

50. The assembly of claim 49 wherein the first and second piezoelectric transducers each comprise polyvinylidene copolymer sheets.