Acoustic transducers with bend limiting member

• US 9,100,752 B2
• Filed: 03/14/2014
• Issued: 08/04/2015
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Emo Labs, Inc.
• Original Assignee: Emo Labs, Inc.
• Inventors: Jones, Terrence Keith, Bokaemper, Stefan
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Kaufman, Joshua A
• Application Number:
  US14/211,726
• Publication Number:
  US 20140270278A1
• Time in Patent Office: 508 Days
• Field of Search: 381/152, 381/162, 381/163, 381/191, 381/423, 381/426, 381/431, 381/190, 381/395, 381/388, 381/333, 181/173, 181/167, 181/161, 181/154, 181/166
• US Class Current: 1/1
• CPC Class Codes: H04R 1/00 Details of transducers, loudspeakers or microphones
• CPC Class Codes: H04R 1/026 Supports for loudspeaker casings
• CPC Class Codes: H04R 1/22 for obtaining desired frequency characteristic only circuit for combining transducers having different responses H04R3/00; for hearing aids H04R25/407
• CPC Class Codes: H04R 1/24 Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges
• 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 17/005 using a piezoelectric polymer
• CPC Class Codes: H04R 2217/01 Non-planar magnetostrictive, piezoelectric or electrostrictive benders
• CPC Class Codes: H04R 2307/021 Diaphragms comprising cellulose-like materials, e.g. wood, paper, linen
• CPC Class Codes: H04R 2307/023 Diaphragms comprising ceramic-like materials, e.g. pure ceramic, glass, boride, nitride, carbide, mica and carbon materials
• CPC Class Codes: H04R 2307/025 Diaphragms comprising polymeric materials
• CPC Class Codes: H04R 2307/027 Diaphragms comprising metallic materials
• CPC Class Codes: H04R 2400/11 Aspects regarding the frame of loudspeaker transducers
• CPC Class Codes: H04R 2440/05 Aspects relating to the positioning and way or means of mounting of exciters to resonant bending wave panels
• CPC Class Codes: H04R 5/00 Stereophonic arrangements stereophonic pick-ups H04R9/16, H04R11/12, H04R17/08, H04R19/10
• 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 7/12 Non-planar diaphragms or cones
• CPC Class Codes: H04R 7/16 Mounting or tensioning of diaphragms or cones
• CPC Class Codes: H04R 7/18 at the periphery
• CPC Class Codes: H04R 9/066 using the principle of inertia

Abstract

The invention generally relates to acoustic transducers. In certain aspects, the acoustic transducer includes a diaphragm and a piezoelectric actuator coupled to the diaphragm to cause movement of the diaphragm. In certain aspects, the transducer also includes a member that limits bending of the actuator.

Claims

1. An acoustic transducer, the transducer comprising:

a diaphragm;

a connector coupled to the diaphragm;

a piezoelectric actuator having a proximal end directly coupled to a support and a distal end coupled to the connector wherein movement of the distal end of the actuator is transmitted to the diaphragm by the connector; and

a member that is configured to limit bending of the distal end of the actuator by interacting with the connector wherein said member does not interact with the connector in a normal range of motion of the actuator.

2. The transducer according to claim 1, wherein the transducer employs mechanical amplification.

3. The transducer according to claim 1, wherein the diaphragm is curved.

4. The transducer of claim 3, wherein movements between the actuator and the diaphragm employ mechanical amplification.

5. The transducer of claim 4, further comprising a second actuator configured to act upon the diaphragm such that a plurality of audio signals is emitted separately by the actuator and the second actuator through the diaphragm.

6. The transducer of claim 5, wherein the plurality of audio signals includes a right and a left stereo signal.

7. The transducer of claim 5, wherein the plurality of audio signals includes a right, a left, and a center channel.

8. The transducer according to claim 1, wherein a distal end of the connector is coupled to the diaphragm and the member is positioned to interact with the distal end of the connector.

9. The transducer according to claim 1, wherein the member is removably coupled to the transducer.

10. The transducer according to claim 1, wherein the diaphragm is removably coupled to the actuator.

11. The transducer according to claim 1, wherein the connector comprises first and second sides, and the member is configured to interact with only the first or second side.

12. The transducer according to claim 1, wherein the connector comprises first and second sides, and the member is configured to interact with both the first and second sides.

13. The transducer according to claim 1, wherein the member is composed of a material selected from the group consisting of a plastic and a rubber.

14. The transducer according to claim 1, wherein the member comprises first and second vertical sides and a top portion that connects the first and second sides.

15. The transducer according to claim 11, wherein the member is sized to fit over the actuator.

16. The transducer according to claim 1, wherein the diaphragm is composed of a material selected from the group consisting of plastic, metal, paper, carbon-fiber composite, fabric, foam, paper, and a combination thereof.

17. The transducer according to claim 1, wherein the piezoelectric actuator is a bending-type piezoelectric actuator.

18. The transducer according to claim 17, wherein the bending-type actuator is a unimorph, bimorph, or multimorph actuator.

19. The transducer according to claim 1, wherein the member is configured to not limit movement of the diaphragm.

20. The transducer according to claim 1, wherein the transducer further comprises a base and the member is an integral part of the base.

21. The transducer according to claim 1, wherein the member restricts bending of the actuator by 0.001 mm to 10 mm on either side of the actuator.

22. The transducer according to claim 1, wherein the member comprises two independently adjustable parts on either side of the connector so that a gap between the connector and each part of the member may be adjusted.

23. The transducer according to claim 22, wherein the gap between the member and the connector is achieved by first fixing the position of the actuator in an assembly operation such as gluing, clamping or welding with the member in a first position and then achieving the designed gap when the member is moved to a second position.

24. The transducer according to claim 23, wherein the member and the connector are tapered along the surfaces where they interact, relative to the center plane of the actuator so that the angle of the taper provides a means to accurately establish a gap that is smaller than plus or minus 0.1 mm.

25. The transducer according to claim 24, wherein the angle of taper is two degrees.

26. An acoustic transducer, the transducer comprising:

a curved diaphragm;

a first actuator operably coupled to a face of the curved diaphragm, near one end of the face;

a second actuator operably coupled to the same face of the curved diaphragm, near an opposite end of the face;

a support;

a connector coupled to the diaphragm and a distal end of the first actuator or a distal end of the second actuator wherein movement of at least one of the distal end of the first actuator or the distal end of the second actuator is transmitted to the diaphragm by the connector; and

a member that is configured to limit bending of at least one of the first actuator or the second actuator by interacting with the connector wherein said member does not interact with the connector in a normal range of motion of the first or second actuator;

wherein movements between the actuator and the diaphragm employ mechanical amplification; and

wherein the first and second actuators are configured to move simultaneously in opposite directions so that the diaphragm oscillates between a greater and a lesser degree of curvature around a resting degree of curvature.