Double-resonator micro-speaker assemblies and methods for tuning the same

• US 20040203494A1
• Filed: 09/27/2002
• Published: 10/14/2004
• Est. Priority Date: 09/27/2002
• Status: Active Grant

• Current Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Inventors: Eaton, William Chris
• Granted Patent: US 7,123,736 B2
• Time in Patent Office: Days
• US Class Current: 455/90.1
• CPC Class Codes: H04M 1/035 Improving the acoustic characteristics by means of constructional features of the housing, e.g. ribs, walls, resonating chambers or cavities
• CPC Class Codes: H04R 1/2842 for loudspeaker 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

Micro-speaker assemblies and mobile terminals including micro-speaker assemblies are provided. The micro-speaker assemblies include a micro-speaker positioned in a housing. A first forward tuning volume is positioned adjacent a front face of the micro-speaker. A passageway extends from the first forward tuning volume to an opening in the housing. A second forward tuning volume in fluid communication with the passageway is positioned at a location between the first forward tuning volume and the opening in the housing. The second forward tuning volume, the first forward tuning volume and the passageway define a double-resonator that tunes a frequency response of the micro-speaker. Methods for tuning micro-speakers are also provided.

Claims

1. A mobile terminal, comprising:

a portable housing;

a micro-speaker positioned in the housing;

a first forward tuning volume adjacent a front face of the micro-speaker;

a passageway extending from the first forward tuning volume to an opening in the housing; and

a second forward tuning volume in fluid communication with the passageway and positioned at a location between the first forward tuning volume and the opening in the housing, the second forward tuning volume, the first forward tuning volume and the passageway defining a double-resonator that tunes a frequency response of the micro-speaker.

2. The mobile terminal of claim 1 wherein the frequency response of the micro-speaker is tuned to provide an amplitude response in a voice frequency range and a high amplitude response, greater than the response in the voice frequency range, at an alert frequency.

3. The mobile terminal of claim 2 wherein the minimum amplitude response in the voice frequency range is at least about −

20 decibels (dB) and wherein the alert frequency is between about 3000 hertz (Hz) and about 4000 Hz.

4. The mobile terminal of claim 2 wherein the minimum amplitude response in the voice frequency range is at least about −

10 decibels (dB).

5. The mobile terminal of claim 3 wherein the frequency response of the micro-speaker is tuned to provide an amplitude response in an extended frequency range above the voice frequency range.

6. The mobile terminal of claim 5 wherein the amplitude response in the extended frequency range is at least about −

20 decibels (dB) and wherein the extended frequency range is up to at least about 8000 hertz (Hz).

7. The mobile terminal of claim 2 wherein the alert frequency is a first resonance frequency of the double-resonator greater than about 3000 hertz (Hz) and wherein a second resonance frequency of the double-resonator, greater than the first resonance frequency, is selected to provide an extended frequency range above the voice frequency range.

8. The mobile terminal of claim 7 wherein the second resonance frequency is between about 6000 hertz (Hz) and about 8000 hertz (Hz).

9. The mobile terminal of claim 1 wherein the mobile terminal further comprises a back tuning volume adjacent a side of the micro-speaker opposite the first forward tuning volume.

10. The mobile terminal of claim 9 wherein the back tuning volume is at least an order of magnitude larger than each of the first forward tuning volume and the second forward tuning volume.

11. The mobile terminal of claim 1 wherein the opening has an area of less than about 10 square millimeters (mm²).

12. The mobile terminal of claim 1 wherein the micro-speaker has a bandwidth of at least about 8000 hertz (Hz).

13. The mobile terminal of claim 1 wherein the micro-speaker has a bandwidth of at least about 10000 hertz (Hz).

14. The mobile terminal of claim 1 wherein the micro-speaker has a diameter of between about 10 millimeters (mm) and about 20 mm.

15. The mobile terminal of claim 1 wherein the second forward tuning volume is positioned adjacent a wall of the housing and wherein the opening is in the wall and wherein a length of the passageway from the second forward tuning volume to the opening is about a thickness of the wall of the housing.

16. The mobile terminal of claim 1 further comprising;

a receiver that receives voice signals from a wireless communications network; and

a controller that decodes the voice signals and provides the decoded voice signals to the micro-speaker.

17. The mobile terminal of claim 16 wherein the passageway extends about 5 millimeters (mm) and wherein the first and second forward tuning volumes are each less than about 0.2 cubic centimeters and wherein the opening has an area of less than about 10 square millimeters (mm²).

18. The mobile terminal of claim 16 wherein the frequency response of the micro-speaker is tuned to provide a minimum amplitude response of about −

20 decibels (dB) up to about 8000 hertz (Hz) and a high amplitude response, greater than the minimum amplitude response at an alert frequency between about 3000 hertz (Hz) and about 4000 Hz.

19. A micro-speaker assembly, comprising:

a micro-speaker positioned in a housing;

a first forward tuning volume adjacent a front face of the micro-speaker;

a passageway extending from the first forward tuning volume to an opening in the housing; and

a second forward tuning volume in fluid communication with the passageway and positioned at a location between the first forward tuning volume and the opening in the housing, the second forward tuning volume, the first forward tuning volume and the passageway defining a double-resonator that tunes a frequency response of the micro-speaker.

20. The micro-speaker assembly of claim 19 wherein the frequency response of the micro-speaker is tuned to provide an amplitude response in a voice frequency range and an extended frequency range from the voice frequency range up to at least about 8000 hertz (Hz), and wherein the frequency response of the micro-speaker is further tuned to provide a high amplitude response, greater than the response in the voice frequency range, at an alert frequency of less than about 8000 Hz.

21. The micro-speaker assembly of claim 20 wherein the amplitude response in the voice frequency range and the extended frequency range is at least about −

20 decibels (dB) and wherein the alert frequency is between about 3000 hertz (Hz) and about 4000 Hz.

22. The micro-speaker assembly of claim 20 wherein the alert frequency is a first resonance frequency of the double-resonator greater than about 3000 hertz (Hz) and wherein a second resonance frequency of the double-resonator, greater than the first resonance frequency, is selected to provide a minimum amplitude response of about −

20 decibels (dB) from above the voice frequency range to at least about 8000 Hz.

23. The micro-speaker assembly of claim 22 wherein the second resonance frequency is between about 6000 hertz (Hz) and about 8000 hertz (Hz).

24. The micro-speaker assembly of claim 19 wherein the opening has an area of less than about 10 square millimeters (mm²).

25. The micro-speaker assembly of claim 24 wherein the micro-speaker has a diameter of between about 10 millimeters (mm) and about 20 mm.

26. The micro-speaker assembly of claim 19 wherein the double-resonator extends the frequency response of the micro-speaker above a voice frequency range.

27. A method for tuning a micro-speaker, comprising:

selecting a volume of a first forward tuning volume adjacent a front face of a micro-speaker to define a first resonant frequency of the micro-speaker, the first resonant frequency providing an amplitude response in a voice frequency range and a high amplitude response, greater that the response in the voice frequency range, at the first resonant frequency; and

selecting a volume of a second forward tuning volume and a position of the second forward tuning volume on a passageway of the micro-speaker assembly extending from the first forward tuning volume to an opening in a housing containing the micro-speaker assembly to define a second resonant frequency of the micro-speaker, the second resonant frequency being greater than the first resonant frequency and wherein the second resonant frequency provides an amplitude response up to at least about 8000 hertz (Hz).

28. The method of claim 27 wherein the amplitude responses in the voice frequency range and up to at least about 8000 hertz (Hz) are at least about −

20 decibels (dB).

29. The method of claim 28 wherein the first resonant frequency is between about 3000 hertz (Hz) and about 4000 Hz.

30. The method of claim 29 wherein the opening has an area of less than about 10 square millimeters (mm²).

31. A micro-speaker assembly comprising:

a micro-speaker positioned in a housing; and

a double-resonator acoustically coupled to the micro-speaker having a first resonance frequency at an alert frequency above the voice frequency band and a second resonance frequency above the first resonance frequency.

32. The micro-speaker assembly of claim 31 wherein the first resonance frequency is between about 3400 hertz (Hz) and 5000 Hz and wherein the second resonance frequency is between about 4000 Hz and about 10000 Hz.

33. The micro-speaker assembly of claim 32 wherein the first resonance frequency is between about 3000 hertz (Hz) and about 4000 Hz and wherein the second resonance frequency is between about 6000 Hz and about 8000 Hz.