Acoustic vibration generating element

• US 20050129257A1
• Filed: 11/15/2004
• Published: 06/16/2005
• Est. Priority Date: 12/12/2003
• Status: Abandoned Application

• Current Assignee: NEC Tokin Corporation (Yageo Corporation)
• Original Assignee: NEC Tokin Corporation (Yageo Corporation)
• Inventors: Tamura, Mitsuo
• Application Number:
  US10/990,117
• Publication Number:
  US 20050129257A1
• Time in Patent Office: Days
• US Class Current: 381/151
• 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 17/10 Resonant transducers, i.e. adapted to produce maximum output at a predetermined frequency
• CPC Class Codes: H04R 2460/13 Hearing devices using bone conduction transducers
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's

Abstract

In an acoustic vibration generating element, a piezoelectric bimorph element or unimorph element is covered with a covering member of a flexible material at least on two surfaces perpendicular to a thickness direction. The covering member may be provided with a plurality of V-shaped grooves so as to improve a generated vibrating force. Alternatively, the covering member may be provided with an air chamber in the vicinity of a surface of one side so as to prevent sound leakage. Further, the covering member and an earhook may be integrally formed by the flexible material so as to achieve a light-weight acoustic vibration generating element suitable for a bone conduction speaker.

Claims

1. A bone conduction acoustic vibration generating element comprising a piezoelectric bimorph or unimorph element and covering members made of a flexible material and attached to at least two surfaces perpendicular to a thickness direction of the piezoelectric bimorph or unimorph element.

2. The bone conduction acoustic vibration generating element according to claim 1, wherein each of the covering members is provided with a plurality of grooves formed on its surface.

3. The bone conduction acoustic vibration generating element according to claim 1, wherein one of the covering members is provided with an air chamber.

4. The bone conduction acoustic vibration generating element according to any one of claims 1 to 3, wherein the piezoelectric bimorph element has a laminated structure comprising piezoelectric ceramics sheets and internal electrodes.

5. The bone conduction acoustic vibration generating element according to any one of claims 1 to 3, further comprising an earhook portion made of the flexible material and integrally formed with the covering member.

6. The bone conduction acoustic vibration generating element according to claim 4, further comprising an earhook portion made of the flexible material and integrally formed with the covering member.

7. A bone conduction acoustic vibration generating element comprising a piezoelectric bimorph or unimorph element and a covering member made of a flexible material and covering a whole of the piezoelectric bimorph element or the piezoelectric unimorph element.

8. The bone conduction acoustic vibration generating element according to claim 7, wherein the covering member is provided with a plurality of grooves formed on its surface.

9. The bone conduction acoustic vibration generating element according to claim 7, wherein the covering members is provided with an air chamber formed on one side thereof.

10. The bone conduction acoustic vibration generating element according to any one of claims 7 to 9, wherein the piezoelectric bimorph element has a laminated structure comprising piezoelectric ceramics sheets and internal electrodes.

11. The bone conduction acoustic vibration generating element according to any one of claims 7 to 9, further comprising an earhook portion made of the flexible material and integrally formed with the covering member.

12. The bone conduction acoustic vibration generating element according to claim 10, further comprising an earhook portion made of the flexible material and integrally formed with the covering member.