Optically Clear Diaphragm For An Acoustic Transducer And Method For Making Same

• US 20100224437A1
• Filed: 03/06/2009
• Published: 09/09/2010
• Est. Priority Date: 03/06/2009
• Status: Active Grant

• Current Assignee: Emo Labs, Inc.
• Original Assignee: Emo Labs, Inc.
• Inventors: White, Robert H. JR., Booth, Jeffrey Davis, Bokaemper, Stefan
• Granted Patent: US 8,189,851 B2
• Time in Patent Office: Days
• US Class Current: 181/166
• CPC Class Codes: G02C 11/06 Hearing aids construction of hearing aids H04R25/00
• CPC Class Codes: H04R 1/2819 for loudspeaker transducers
• CPC Class Codes: H04R 17/00 Piezoelectric transducers; Electrostrictive transducers piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners H10N30/00
• CPC Class Codes: H04R 2207/00 Details of diaphragms or cones for electromechanical transducers or their suspension covered by H04R7/00 but not provided for in H04R7/00 or in H04R2307/00
• CPC Class Codes: H04R 23/002 using electrothermic-effect transducer
• CPC Class Codes: H04R 2307/025 Diaphragms comprising polymeric materials
• CPC Class Codes: H04R 2499/15 Transducers incorporated in visual displaying devices, e.g. televisions, computer displays, laptops
• CPC Class Codes: H04R 31/003 for diaphragms or their outer suspension
• CPC Class Codes: H04R 7/00 Diaphragms for electromechanical transducers in general F16J3/00; Cones for musical instruments G10 cones, diaphragms or the like, for emitting or receiving sound in general G10K13/00; Mounting thereof
• CPC Class Codes: H04R 7/02 characterised by the construction
• CPC Class Codes: H04R 7/04 Plane diaphragms
• CPC Class Codes: H04R 7/045 using the distributed mode principle, i.e. whereby the acoustic radiation is emanated from uniformly distributed free bending wave vibration induced in a stiff panel and not from pistonic motion
• CPC Class Codes: H04R 7/10 comprising superposed layers in contact
• CPC Class Codes: H04R 7/125 comprising a plurality of superposed layers in contact
• CPC Class Codes: H04R 7/26 Damping by means acting directly on free portion of diaphragm or cone air damping H04R1/28
• CPC Class Codes: H04R 9/06 Loudspeakers

Abstract

The present disclosure relates to a diaphragm that may be used with a mechanical-to-acoustical transducer. The diaphragm may include a layer of optically clear film, a damping layer and another layer of optically clear film. The damping layer may be an adhesive. The diaphragm may also comprise two optically clear films, optionally including a damping layer, wherein the films indicate a desired coefficient of linear thermal expansion in one or both of the machine and transverse directions.

Claims

1. A diaphragm for use with a mechanical-to-acoustical transducer comprising:

(a) a layer of optically clear film;

(b) a damping layer;

(c) a layer of optically clear film;

wherein the diaphragm has a composite damping value of tan delta equal to or greater than 0.04 in the frequency range of 500 Hz to 2000 Hz at 30°

C., wherein said diaphragm has a total luminous transmittance of equal to or greater than 75%.

2. The diaphragm of claim 1 wherein said diaphragm has a damping value of tan delta equal to or greater than 0.06 in the frequency range of 500 Hz to 2000 Hz at 30°

C.

3. The diaphragm of claim 1 wherein said diaphragm has a damping value of tan delta equal to or greater than 0.08 in the frequency range of 500 Hz to 2000 Hz at 30°

C.

4. The diaphragm of claim 1 wherein the composite damping value is 0.04 to 0.5 at said frequency range from 500 Hz to 2000 Hz at 30°

C.

5. The diaphragm of claim 1 wherein the damping layer has a damping value of tan delta that is equal to or greater than 0.1 at said frequency range from 500 Hz to 2000 Hz at 30°

C.

6. The diaphragm of claim 1 wherein the damping layer has a damping value of tan delta of 0.1 to 10 at said frequency range from 500 Hz to 2000 Hz at 30°

C.

7. The diaphragm of claim 1 wherein the two optical films each have a modulus value and the damping layer has a modulus value and the damping layer modulus value is at least ten times lower than the modulus value of the smaller of the two modulus values for said optical films.

8. The diaphragm of claim 1 wherein the two optical films each have a modulus values and the damping layer has a modulus value and the damping layer modulus value is at least one hundred times lower than the modulus value of the smaller of the two modulus values for said optical films.

9. The diaphragm of claim 1 wherein said composite damping value tan delta of the diaphragm is at least 1.5 times as high as any of the tan delta damping values of the optically clear films at said frequency range from 500 Hz to 2000 Hz at 30°

C.

10. The diaphragm of claim 1 where the thickness of the damping layer is in the range of 1 μ

m to 200 μ

m.

11. The diaphragm of claim 1 wherein said damping layer is an adhesive and one of the optical films is adhered to the damping layer with a peel strength of greater than or equal to 0.005 N/inch.

12. The diaphragm of claim 11 wherein said peel strength is 0.005N/inch to 500 N/inch.

13. The diaphragm of claim 1 wherein the diaphragm has a composite modulus of equal to or greater than 2.0 GPa.

14. The diaphragm of claim 1 wherein at least one of said optically clear films has an elastic modulus of equal to or greater than 2.0 GPa.

15. The diaphragm of claim 1 wherein the diaphragm has a neutral axis and two outer layers and said neutral axis is not contained within said damping layer, and one of said outer layers is closer to said damping layer than the other of the two outer layers.

16. The diaphragm of claim 1 wherein the damping layer has a centerline that is positioned at least 25% of the distance between a neutral axis of the diaphragm and an outer surface of the diaphragm that is closest to said damping layer.

17. The diaphragm of claim 1 wherein said diaphragm has a haze value and the haze value is less than or equal to 30%.

18. The diaphragm of claim 1 wherein said optically clear films have a coefficient of linear thermal expansion (CLTE) in a machine direction (MD) and transverse direction (TD), and the CLTE for said films, in either said MD or TD, is less than or equal to 50 μ

m/m/°

C. when measured at 20°

C. to 50°

C.

19. The diaphragm of claim 1 wherein said damping layer is a pressure sensitive adhesive.

20. The diaphragm of claim 1 wherein at least one of said optically clear films has a density that is equal to or less than 1500 kg/m³.

21. The diaphragm of claim 1 wherein said diaphragm has a thickness of 100 μ

m to 2 mm.

22. The diaphragm of claim 1 wherein said optically clear films have a heat shrinkage in the machine direction and transverse direction and said heat shrinkage is less than or equal to 0.5% in the machine direction as well as in the transverse direction (TD).

23. The diaphragm of claim 1 wherein the diaphragm is coupled to a mechanical-to-acoustical transducer within an audio speaker.

24. The diaphragm of claim 1 wherein the diaphragm has an edge and the edge of the diaphragm is coupled to a mechanical-to-acoustical transducer within an audio speaker.

25. The diaphragm of claim 1 positioned over a display that provides visual information to a viewer.

26. A diaphragm for use with a mechanical-to-acoustical transducer comprising:

(a) a layer of optically clear film;

(b) a damping layer;

(c) a layer of optically clear film;

wherein the damping layer has a damping value of tan delta that is equal to or greater than 0.1 at said frequency range from 500 Hz to 2000 Hz at 30°

C.

27. The diaphragm of claim 26 wherein the damping layer has a damping value of tan delta that is equal to or greater than 0.2 at said frequency range from 500 Hz to 2000 Hz at 30°

C.

28. The diaphragm of claim 26 wherein the damping layer has a damping value of tan delta of 0.1 to 10 said frequency range from 500 Hz to 2000 Hz at 30°

C.

29. The diaphragm of claim 26 wherein the two optical films each have a modulus value and the damping layer has a modulus value and the damping layer modulus value is at least ten times lower than the modulus value of the smaller of the two modulus values for said optical films.

30. The diaphragm of claim 26 wherein the two optical films each have a modulus values and the damping layer has a modulus value and the damping layer modulus value is at least one hundred times lower than the modulus value of the smaller of the two modulus values for said optical films.

31. The diaphragm of claim 26 wherein the composite damping value tan delta of the diaphragm is at least 1.5 times as high as any of the tan delta damping values of the optically clear films at said frequency range from 500 Hz to 2000 Hz at 30°

C.

32. The diaphragm of claim 26 where the thickness of the damping layer is in the range of 1 μ

m to 200 μ

m.

33. The diaphragm of claim 26 wherein said damping layer is an adhesive and one of the optical films is adhered to the damping layer with a peel strength of greater than or equal to 0.005 N/inch.

34. The diaphragm of claim 26 wherein said peel strength is 0.005N/inch to 500 N/inch.

35. The diaphragm of claim 26 wherein the diaphragm has a composite modulus of equal to or greater than 2.0 GPa.

36. The diaphragm of claim 26 wherein at least one of said optically clear films has an elastic modulus of equal to or greater than 2.0 GPa.

37. The diaphragm of claim 26 wherein the diaphragm has a neutral axis and two outer layers and said neutral axis is not contained within said damping layer, and one of said outer layers is closer to said damping layer than the other of the two outer layers.

38. The diaphragm of claim 26 wherein the damping layer has a centerline that is positioned at least 25% of the distance between a neutral axis of the diaphragm and an outer surface of the diaphragm that is closest to said damping layer.

39. The diaphragm of claim 26 wherein said diaphragm has a haze value and the haze value is less than or equal to 30%.

40. The diaphragm of claim 26 wherein said optically clear films have a coefficient of linear thermal expansion (CLTE) in a machine direction (MD) and transverse direction (TD), and the CLTE for said films, in either said MD or TD, is less than or equal to 50 μ

m/m/°

C. when measured at 20°

C. to 50°

C.

41. The diaphragm of claim 26 wherein said damping layer is a pressure sensitive adhesive.

42. The diaphragm of claim 26 wherein at least one of said optically clear films has a density that is equal to or less than 1500 kg/m³.

43. The diaphragm of claim 26 wherein the diaphragm is coupled to a mechanical-to-acoustical transducer within an audio speaker.

44. The diaphragm of claim 26, wherein the diaphragm has an edge and the edge of the diaphragm is coupled to a mechanical-to-acoustical transducer within an audio speaker.

45. The diaphragm of claim 26 positioned over a display that provides visual information to a viewer.

46-70. -70. (canceled)