DIGITAL LOUDSPEAKER WITH ENHANCED PERFORMANCE

• US 20130294636A1
• Filed: 05/06/2013
• Published: 11/07/2013
• Est. Priority Date: 05/07/2012
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Cassett, Fabrice, Dejaeger, Remy
• Granted Patent: US 9,282,385 B2
• Time in Patent Office: Days
• US Class Current: 381/386
• CPC Class Codes: H04R 1/005 using digitally weighted transducing elements
• CPC Class Codes: H04R 1/02 Casings; Cabinets ; Supports therefor; Mountings therein H04R1/28 takes precedence ; attachments for microphones H04R1/08; mounting of transducers in earpieces H04R1/1075
• CPC Class Codes: H04R 1/406 microphones
• 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

Abstract

Digital loudspeaker comprising a support, a plurality of first membranes suspended on the support, said first membranes being bistable, and said loudspeaker comprising actuator for each of the first membranes that can change each of the first membranes from a first stable state to a second stable state and vice versa, and a controller for controlling said first actuator.

Claims

1. A digital loudspeaker comprising:

a support;

a plurality of first membranes suspended on the support, said first membranes being bistable;

a first actuator for each of the first membranes that can change each of the first membranes from a first stable state to a second stable state and vice versa; and

a controller to control said first actuator.

2. A digital loudspeaker according to claim 1, in which said first membranes form a first group of membranes, and the loudspeaker comprises at least one second group of second membranes and a second actuator for each of the second membranes, the first and the second actuator being controlled separately by the controller.

3. A digital loudspeaker according to claim 2, in which the first membranes and the second membranes are initially in different stable states.

4. A digital loudspeaker according to claim 2, in which the first membranes and the second membranes are initially in the same stable state.

5. A digital loudspeaker according to claim 2, in which the number of first membranes and the number of second membranes are equal.

6. A loudspeaker according to claim 2, in which the controller is configured to send a reinitialisation signal to the first membranes and/or the second membranes, before a control signal is sent.

7. A digital loudspeaker according to claim 2, in which the first actuator and/or the second actuator are piezoelectric actuators, comprising at least one element made of piezoelectric material in contact with each of the membranes and control electrodes associated with each element, said control electrodes being configured to apply a control voltage to each element made of a piezoelectric material.

8. A digital loudspeaker according to claim 2, in which the first actuator and/or the second actuator are thermal actuators, each comprising an element forming an electrical resistance controlled by the controller and arranged in contact with each of the membranes, each electrical resistance being capable of applying a mechanical torque to the membrane associated with it.

9. A digital loudspeaker according to claim 7, in which the piezoelectric element arranged on the membrane has a surface area equal to between 0.4 and 0.6 times the surface area of the membrane.

10. A digital loudspeaker according to claim 1, wherein the loudspeaker is made using microelectronic methods.

11. A method for making a loudspeaker according to claim 1 comprising the following steps:

a) making a layer in which the membranes will be formed;

b) making a first actuator and/or a second actuator;

c) releasing the membranes; and

d) connecting the first actuator and/or the second actuator to the controller.

12. A method according to claim 11, in which the layer formed in step a) is made with at least one predefined stress level.

13. A method according to claim 11, in which during step a), different predetermined stress levels are applied to different zones in the layer that will form the membranes so as to form the first membranes and the second membranes that will be in different stable states when they are released in step c).

14. A method according to claim 11, in which between step c) and step d), the method further comprises

cutting out the device obtained to form two sub-elements or membrane groups,

and during step d), the two sub-elements are assembled and the first actuator and the second actuator are electrically connected to the controller such that the membranes of the two sub-elements are in different stable states.

15. A method according to claim 14, in which one of the sub-assemblies is turned over.

16. A method according to claim 11, in which part of the actuator is actuated to force the membranes associated with said actuator to change to the other stable state.