Mechanically actuated panel acoustic system

• US 9,525,943 B2
• Filed: 11/24/2014
• Issued: 12/20/2016
• 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): ADDY, THJUAN KNOWLIN
• Application Number:
  US14/551,631
• Publication Number:
  US 20160150318A1
• Time in Patent Office: 757 Days
• Field of Search: 381/104, 381/152, 381/337, 381/150, 381/339
• US Class Current: 1/1
• 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 includes an enclosure or housing panel that is used as part of an acoustic system. 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 audio device, wherein the panel is divided into a plurality of sub-panels defined by one or more backing frames attached to the panel;

a plurality of sub-panel actuators each being attached to a respective one 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.

2. The electronic audio device of claim 1 wherein the one or more backing frames 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 audio device of claim 2, wherein the panel has uniform thickness over all of the sub-panels.

4. The electronic audio 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 audio 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.

6. The electronic audio device of claim 1, wherein sub-panel division is such that no surface area of any of the plurality of sub-panels overlaps another.

7. The electronic audio 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.

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

17. The electronic audio device of claim 1, wherein the panel comprises glass or aluminum.

18. The electronic audio device of claim 1, wherein the panel is a part of the outer enclosure of one of the following:

a laptop computer, a handheld electronic device, a mobile telephone, a tablet computer, a display device, or an audio playback device.

9. A method for producing an audible sound on a device, the method comprising:

receiving an audio signal;

generating a plurality of sub-band audio signals by filtering the audio signal;

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

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

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,

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, and

wherein the resonance frequency of the sub-panel corresponds to a note on a musical scale.

10. The method of claim 9, wherein the spectral content of the sub-band audio signal is at the resonance frequency of the sub-panel that is driven by the sub-band audio signal.

11. The method of claim 9, 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.

12. The method of claim 9, 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.

13. The method of claim 9, wherein acoustic summation of the plurality of sub-panels produces low frequency sound over a wide band.

14. An apparatus comprising:

a panel that is divided into a plurality of sub-panels defined by one or more backing frames attached to the panel;

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.

15. The apparatus of claim 14 wherein the one or more backing frames 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.

16. The apparatus of claim 15, wherein at least two of the sub-panels have different resonance frequencies.

19. The apparatus of claim 14, wherein the panel comprises glass or aluminum.

20. The apparatus of claim 14, wherein the panel is a part of an outer enclosure of one of the following:

a laptop computer, a handheld electronic device, a mobile telephone, a tablet computer, a display device, or an audio playback device.