Mechanically actuated panel acoustic system

• US 10,362,403 B2
• Filed: 10/29/2015
• Issued: 07/23/2019
• Est. Priority Date: 11/24/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Donarski, Matthew A., Boothe, Daniel K., Crosby, Justin D., Lerner, Mitchell R.
• Primary Examiner(s): Goins, Davetta W
• Assistant Examiner(s): Sellers, Daniel R
• Application Number:
  US15/510,678
• Publication Number:
  US 20170223462A1
• Time in Patent Office: 1,363 Days
• 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 1/2811 for loudspeaker transducers
• CPC Class Codes: H04R 2430/03 Synergistic effects of band splitting and sub-band processing
• CPC Class Codes: H04R 2440/00 Bending wave transducers covered by H04R, not provided for in its groups
• 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 3/14 Cross-over networks
• 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

Abstract

An electronic device whose enclosure or housing panel is used as part of an acoustic system is described. The panel is divided into several sub-panels. For each sub-panel, the device includes one or more actuators attached to vibrate the sub-panel. The actuator and its attached sub-panel convert an audio signal to acoustic output. Each actuator and sub-panel combination may receive a separate audio signal. The device includes a digital signal processor for controlling each of the sub-panel driving audio signals. The device may further include one or more backing frames that are attached to the panel to provide boundary conditions to the sub-panels. The boundary conditions define a resonance frequency for each sub-panel.

Claims

1. An electronic audio device comprising:

a panel that is a part of an outer enclosure of the electronic device, wherein the panel is divided into a plurality of sub-panels, and wherein each sub-panel of the plurality of sub-panels has a resonance frequency that corresponds to a note on a musical scale;

a plurality of sub-panel actuators each being attached to a respective sub-panel of the plurality of sub-panels and that is to convert a respective sub-panel audio signal into acoustic output by vibrating the respective sub-panel; and

a plurality of digital signal processors each to control the respective sub-panel audio signal that is driving the sub-panel actuator, wherein a digital signal processor of the plurality of digital signal processors receives an audio signal and filters the audio signal to generate the respective sub-panel audio signal, wherein a majority of energy of the respective sub-panel audio signal is at or around the resonance frequency of the respective sub-panel.

2. The electronic device of claim 1 further comprising one or more backing frames that are attached to the panel to provide boundary conditions to the plurality of sub-panels, wherein the boundary conditions define a resonance frequency for each sub-panel.

3. The electronic device of claim 2, wherein at least two of the sub-panels have different resonance frequencies.

4. The electronic device of claim 2, wherein spectral content of the respective sub-panel audio signal is at or around the resonance frequency of the sub-panel.

5. The electronic device of claim 4, wherein sum of the acoustic outputs of the plurality of sub-panels produces low frequency sound over a wide frequency band.

6. The electronic device of claim 2, wherein the one or more backing frames have air passages that connect back air volume of the plurality of sub-panels so that the plurality of sub-panels share a back air volume.

7. The electronic device of claim 1, wherein sub-panel division is left-right symmetric and the plurality of sub-panels can produce stereo audio.

8. The electronic device of claim 1, wherein sub-panel division is non-symmetric and two or more of the plurality of sub-panels can be excited to produce mono-audio.

9. The electronic device of claim 1, wherein each sub-panel has a sealed back volume.

10. A method for producing an audible sound on a device including a panel that is divided into a plurality of sub-panels, the method comprising:

receiving an audio signal;

generating a plurality of sub-band audio signals by filtering the audio signal, wherein the audio signal is filtered such that a majority of energy of a respective one of the plurality sub-band audio signals is at or around a resonance frequency of a respective sub-panel of the plurality of sub-panels;

processing the plurality of sub-band audio signals separately; and

driving a plurality of actuators associated with the plurality of sub-panels of the panel of the device with the plurality of processed sub-band audio signals, wherein the panel is a part of an enclosure of the device.

11. The method of claim 10, wherein each of the plurality of sub-band audio signals drives one or more actuators associated with a sub-panel of the plurality of sub-panels.

12. The method of claim 11, wherein spectral content of a sub-band audio signal is at a resonance frequency of a sub-panel that is driven by the sub-band audio signal.

13. The method of claim 11, wherein spectral content of a sub-band audio signal surrounds a resonance frequency of a sub-panel that is driven by the sub-band audio signal.

14. The method of claim 13, wherein the processing of the sub-band audio signal comprises:

for each frequency component within the sub-band audio signal, determining whether amplitude of the sub-band audio signal at the frequency component exceeds a threshold; and

aligning the sub-band audio signal at the frequency component to the resonance frequency of the sub-panel when the amplitude of the sub-band audio signal at the frequency component exceeds the threshold.

15. The method of claim 13, wherein the resonance frequency of the sub-panel corresponds to a note on a musical scale.

16. The method of claim 10, wherein each of the plurality of sub-band audio signals is processed individually so that acoustic outputs of the plurality of sub-panels are coherent and can be combined constructively.

17. The method of claim 10, wherein acoustic summation of the plurality of sub-panels produces low frequency sound over a wide band.

18. An apparatus comprising:

a panel that is divided into a plurality of sub-panels, wherein each sub-panel of the plurality of sub-panels has a resonance frequency that corresponds to a note on a musical scale;

for each of the plurality of sub-panels, one or more actuators attached to the sub-panel and that is to convert a respective sub-panel audio signal into acoustic output by vibrating the sub-panel; and

for each of the plurality of sub-panels, a digital signal processor that is to control the respective sub-panel audio signal that is driving the one or more actuators attached to the sub-panel, wherein the digital signal processor receives an audio signal and filters the received audio signal to generate the respective sub-band audio signal such that a majority of energy of the respective sub-panel audio signal is at or around the resonance frequency of the respective sub-panel.

19. The apparatus of claim 18 further comprising one or more backing frames that are attached to the panel to provide boundary conditions to the plurality of sub-panels, wherein the boundary conditions define the resonance frequency for each sub-panel.

20. The apparatus of claim 19, wherein at least two of the sub-panels have different resonance frequencies.