ACOUSTIC PRESSURE TRANSDUCER

• US 20120027236A1
• Filed: 01/14/2009
• Published: 02/02/2012
• Est. Priority Date: 01/14/2009
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Jilani, Adel, McKinnell, James, Wu, Jennifer, Valencia, Melinda, Homeijer, Brian, Homeijer, Biian
• Granted Patent: US 8,705,774 B2
• Time in Patent Office: Days
• US Class Current: 381/190
• CPC Class Codes: H04R 17/02 Microphones
• CPC Class Codes: H04R 21/02 Microphones
• CPC Class Codes: H04R 2201/003 Mems transducers or their use of the electrostatic type H04R19/005

Abstract

Acoustic transducer means are provided. A monolithic semiconductor layer defines a plate, a pair of oppositely disposed torsional hinges, a flexible extension and at least a portion of a support structure. Acoustic pressure communicated to the plate results in tensile strain of the flexible extension. The flexible extension provides a varying electrical characteristic responsive to the tensile strain. An electric signal corresponding to the acoustic pressure can be derived from the varying electrical characteristic of the flexible extension.

Claims

1. An apparatus, comprising:

a flexure layer defining a plate and a first hinge portion and a second hinge portion, the flexure layer also defining a flexible portion extending away from the plate and configured to exhibit a varying electrical characteristic responsive to an acoustic pressure.

2. The apparatus according to claim 1, the plate being square or rectangular or trapezoidal in shape.

3. The apparatus according to claim 1, the first hinge portion and the second hinge portion extending away from respective opposite sides of the plate.

4. The apparatus according to claim 1, the first hinge portion and the second hinge portion respectively configured to torsionally couple the plate to a support structure, the flexible portion configured to flexibly couple the plate to the support structure.

5. The apparatus according to claim 4, the first hinge portion and the second hinge portion at least partially defined by respective curvaceous portions.

6. The apparatus according to claim 4, the support structure and the flexure layer including the plate and the first hinge portion and the second hinge portion and the flexible portion being formed from a monolithic semiconductor layer.

7. The apparatus according to claim 1 further comprising:

a spine layer bonded to the flexible layer; and

a membrane layer bonded to the spine layer.

8. The apparatus according to claim 7, the spine layer covering that portion of the flexure layer including neither the first hinge portion nor the second hinge portion nor the flexible portion.

9. The apparatus according to claim 8, the spine layer defined by a first area, the membrane layer defined by a second area greater than the first area.

10. The apparatus according to claim 1, the flexible portion including at least one piezoresistive sensor or piezoelectric sensor.

11. A transducer, comprising:

a flexure layer of monolithic material, the flexure layer defining a plate, the flexure layer also defining a first torsional hinge portion and a second torsional hinge portion extending away from opposite sides of the plate, the flexure layer also defining a flexible extension portion;

a spine layer covering the plate of the flexure layer; and

a membrane layer covering the spine layer, the flexible extension portion configured to exhibit an electrical characteristic varying in accordance with an acoustic pressure incident to the membrane layer.

12. The transducer according to claim 11, the first torsional hinge portion and the second torsional hinge portion and the flexible extension portion respectively configured to mechanically couple the plate of the flexure layer to a support structure.

13. The transducer according to claim 11, the flexible extension portion configured such that the electrical characteristic is a resistance or a voltage varying in accordance with an acoustic pressure incident to the membrane layer.

14. The transducer according to claim 11, the first torsional hinge portion and the second torsional hinge portion at least partially defined by respective curvaceous portions.

15. The transducer according to claim 11 further comprising one or more materials configured to define an acoustic cavity, the plate being supported within the acoustic cavity by way of the first and second torsional hinge portions and the flexible extension portion, the membrane layer defining one or more vents fluidly coupling the acoustic cavity to an ambient environment about the microphone.

16. A method, comprising:

displacing a flexure layer of a transducer by influence of an acoustic pressure, the displacing including torsional strain of a pair of hinges and tensile strain of a flexible extension;

varying an electrical characteristic of the flexible extension in accordance with the tensile strain; and

deriving an electrical signal corresponding to the acoustic pressure using the varying electrical characteristic.