Mobile wireless communications device having improved RF immunity of audio transducers to electromagnetic interference (EMI)

• US 7,353,041 B2
• Filed: 04/04/2005
• Issued: 04/01/2008
• Est. Priority Date: 04/04/2005
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Mankaruse, George, Zhu, Lizhong, Corrigan, Michael
• Primary Examiner(s): Mehrpour; Naghmeh
• Application Number:
  US11/098,275
• Publication Number:
  US 20060223570A1
• Time in Patent Office: 1,093 Days
• Field of Search: 455/450.1, 455/298, 455/303, 455/309, 455/310, 455/312, 455/73, 455/88, 455/85, 455/557, 455/558, 455/556, 455/90.1, 455/234.1, 455/234.2, 455/245.1, 455/246.1, 455/250.1
• US Class Current: 455/550.1
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/3833 Hand-held transceivers
• CPC Class Codes: H04M 1/026 Details of the structure or mounting of specific components
• CPC Class Codes: H04M 1/6016 in the receiver circuit
• CPC Class Codes: H04M 1/724 User interfaces specially adapted for cordless or mobile telephones
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49018 with other electrical component

Abstract

A mobile wireless communications device includes a housing and circuit board carried by the housing and having radio frequency (RF) circuitry and a processor operative with each other. Audio circuitry is carried by the circuit board and an audio transducer assembly, such as a speaker, has electrical contacts that electrically engage the audio circuitry for carrying audio signals between the audio circuitry and audio transducer assembly. A filter is mounted at the audio transducer assembly and reduces radio frequency (RF) electromagnetic interference to the audio transducer assembly during device operation.

Claims

1. A mobile wireless communications device comprising:

a housing;

a circuit board carried by the housing and including radio frequency (RF) circuitry and a processor operative with each other;

audio circuitry carried by the circuit board and operative with the RF circuitry and processor;

an audio transducer assembly that includes a housing and carried by the circuit board and having an electrical contact pad member that electrically engages audio circuitry for carrying audio signals between the audio circuitry and the audio transducer assembly wherein the audio circuitry engaging the electrical contact pad member comprises uninterrupted signal traces on the circuit board; and

a filter serially connected within each uninterrupted signal trace of the audio circuitry at the audio transducer assembly, and further comprising a filter mounted serially at the electrical contact pad member and a filter mounted within the housing of the audio transducer assembly for reducing radio frequency (RF) electromagnetic interference to the audio transducer assembly during device operation.

2. A mobile wireless communications device according to claim 1, wherein said audio transducer assembly includes a transducer housing, wherein said filter is positioned within said transducer housing.

3. A mobile wireless communications device according to claim 1, wherein said electrical contacts comprise resilient contact pads that engage the audio circuitry.

4. A mobile wireless communications device according to claim 3, wherein said filter is connected at said audio circuitry adjacent said resilient contact pads.

5. A mobile wireless communications device according to claim 3, wherein said audio transducer comprises a transducer housing and said filter is located between said audio transducer housing and resilient contact pads.

6. A mobile wireless communications device according to claim 1, wherein said filter is located adjacent the electrical contacts of said audio transducer assembly.

7. A mobile wireless communications device according to claim 1, wherein said filter comprises a ferrite bead.

8. A mobile wireless communications device according to claim 1, wherein said filter comprises a surface mount filter device mounted on the circuit board and positioned adjacent said electrical contacts.

9. A mobile wireless communications device according to claim 1, wherein said filter comprises a serial inductor or shunt capacitor.

10. A mobile wireless communications device according to claim 1, wherein said audio transducer assembly comprises a receiver speaker.

11. A mobile wireless communications device according to claim 1, wherein said filter comprises a RF shield that surrounds the audio transducer assembly.

12. A mobile wireless communications device comprising:

a housing;

a circuit board carried by the housing and including radio frequency (RF) circuitry and a processor operative with each other;

an antenna carried by the housing and operative with the RF circuitry;

audio circuitry carried by the circuit board and operative with the RF circuitry and processor and including a receiver audio switch and audio connection lines carried by the circuit board and interconnecting the RF circuitry, processor and receiver audio switch;

a speaker carried by the circuit board and having an electrical contact pad member that electrically engages the audio circuitry for carrying audio signals between the audio circuitry and speaker wherein the audio circuitry engaging the electrical contact pad member comprises uninterrupted signal traces on the circuit board; and

a filter serially connected within each uninterrupted signal trace of the audio circuitry at the speaker, and further comprising a filter mounted serially at the electrical contact pad member and a filter mounted within the housing of the speaker for reducing radio frequency (RF) electromagnetic interference to the speaker during device operation.

13. A mobile wireless communications device according to claim 12, wherein said receiver audio switch includes a detect circuit for detecting when a respective headset is operatively connected to said audio circuitry.

14. A mobile wireless communications device according to claim 12, wherein said audio circuitry further comprises a jack carried by the housing, and jack connection lines carried by said circuit board and operatively connected to said jack, processor and receiver audio switch.

15. A mobile wireless communications device according to claim 12, wherein said filter is serially connected within an audio connection line.

16. A mobile wireless communications device according to claim 12, wherein said speaker comprises a speaker housing and said filter is positioned within said speaker housing.

17. A mobile wireless communications device according to claim 12, wherein said electrical contacts comprise resilient contact pads that engage the audio connection lines.

18. A mobile wireless communications device according to claim 17, wherein said speaker comprises a speaker housing and said filter is located between said speaker housing and resilient contact pads.

19. A mobile wireless communications device according to claim 17, wherein said filter is connected at the audio connection lines adjacent said resilient contact pads.

20. A mobile wireless communications device according to claim 12, wherein said filter is located adjacent the electrical contacts of said speaker.

21. A mobile wireless communications device according to claim 12, wherein said filter comprises a ferrite bead.

22. A mobile wireless communications device according to claim 12, wherein said filter comprises a surface mounted filter device mounted on the circuit board and positioned adjacent said electrical contacts.

23. A mobile wireless communications device according to claim 12, wherein said filter comprises a serial inductor or shunt capacitor.

24. A mobile wireless communications device according to claim 12, wherein said RF filter comprises a RF shield that surrounds the audio transducer assembly.

25. A method of making a mobile wireless communications device, which comprises:

providing a housing, a circuit board carried by the housing and including radio frequency (RF) circuitry and a processor operative with each other, audio circuitry carried by the circuit board and operative with the RF circuitry and processor, and an audio transducer assembly that includes a housing and carried by the circuit board and having an electrical contact pad member that electrically engages audio circuitry for carrying audio signals between the audio circuitry and the audio transducer assembly wherein the audio circuitry engaging the electrical contact pad member comprises uninterrupted signal traces on the circuit board; and

reducing radio frequency (RF) electromagnetic interference to the audio transducer assembly during device operation by serially connecting a filter within each uninterrupted signal trace of audio circuitry at the audio transducer assembly and mounting a filter serially at the electrical contact pad member and a filter within the housing of the audio transducer assembly.

26. A method according to claim 25, which further comprises positioning the filter within a housing of the audio transducer assembly.

27. A method according to claim 25, which further comprises positioning the filter adjacent the electrical contacts.

28. A method according to claim 25, which further comprises forming the filter as a ferrite bead, shunt capacitor or serial inductor.

29. A method according to claim 25, which further comprises forming a RF shield around the audio transducer assembly.