Apparatus and method of detecting proximity inductively

• US 6,545,612 B1
• Filed: 06/20/2000
• Issued: 04/08/2003
• Est. Priority Date: 06/21/1999
• Status: Expired due to Term

• Current Assignee: Optis Wireless Technology, LLC (Brevet Capital)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Lindgren, Ulf, Björk, Christian
• Primary Examiner(s): Wu, Daniel J.
• Application Number:
  US09/597,303
• Time in Patent Office: 1,022 Days
• Field of Search: 340/686.1, 340/686.6, 455/90, 455/550, 455/575, 381/59, 381/98
• US Class Current: 340/686.6
• CPC Class Codes: H04M 1/0202 Portable telephone sets, e.g. cordless phones, mobile phones or bar type handsets constructional features of telephone transmitters or receivers, e.g. of speakers or microphones H04M1/03
• CPC Class Codes: H04M 1/605 involving control of the receiver volume to provide a dual operational mode at close or far distance from the user
• CPC Class Codes: H04M 1/724 User interfaces specially adapted for cordless or mobile telephones
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion telephones including GPS signal receivers H04M2250/10

Abstract

An electronic communications device having a proximity sensor comprising: communication means (7) and a proximity sensor adapted to provide a control signal (Y2; Y3; Y4) indicative of whether an object (8) is in proximity of the device. The device is characterized by having a proximity sensor coil (L1; L2; L3; L5; L6; LP; LL) with an impedance, and oscillation means (C1, C2, 302; 601; 804) coupled to the proximity sensor coil (L1; L2; L3; L5; L6; LP; LL) to provide the control signal (Y2; Y3; Y4) in response to the impedance.

In a preferred embodiment the proximity sensor coil is a loudspeaker coil. The invention also relates to a method of detecting proximity of an object relative to a loudspeaker (11; 703; 803) with a loudspeaker coil (L5; L6) which has an impedance.

Claims

1. An electronic device having a proximity sensor, comprising:

a loudspeaker (11;

703;

803) for receiving an audio signal and having a loudspeaker coil (13;

L5;

L6) with an impedance;

a proximity sensor adapted to provide a control signal (Y2;

Y3) indicative of whether an object (8) is in proximity of the device (1);

characterized by having

oscillation means (C5, C6, 702;

804) coupled to the loudspeaker coil (13, L5;

L6) to provide the control signal (Y2;

Y3) in response to the impedance.

2. An electronic device according to claim 1, characterized in that the oscillation means (C5, C6, 702;

804) has an oscillation frequency (f) which is dependent on the inductance of the loudspeaker coil (13;

L5;

L6).

3. An electronic device according to claim 1, characterized in that the oscillation means (C5, C6, 702;

804) is adapted to provide an oscillating signal with a substantially fixed frequency to the loudspeaker (11;

703;

803).

4. An electronic device according to claim 1, characterized in that the oscillation means comprises a phase-shift oscillator type (C5, C6, 702).

5. An electronic device according to claim 1, characterized in that the oscillation means (C5, C6, 702;

804) has an oscillation frequency oscillating at a frequency above a frequency band of the audio signal.

6. An electronic device according to claim 1, characterized in that the device comprises a front cover (6) made of a material allowing passage of magnetic lines of flux generated by the loudspeaker coil (13;

L5;

L6).

7. An electronic device according to claim 1, characterized in that the loudspeaker coil (13;

L5;

L6) comprises a longitudinal axis (909), and that the coil is mounted such that the longitudinal axis of the coil is inclined relative to the face of a front cover (6).

8. An electronic device according to claim 1, characterized in that the electronic device is a mobile telephone (1).

9. An electronic communications device, having a proximity sensor comprising:

communication means,

a proximity sensor adapted to provide a control signal indicative of whether an object is in the proximity of the device,

a proximity sensor coil with an impedance, and oscillation means coupled to the proximity sensor coil to provide the control signal in response to the impedance,

a loudspeaker having a loudspeaker coil, wherein the proximity sensor coil is integrated in the loudspeaker, wherein the oscillation means is adapted to provide a substantially fixed oscillating signal to the proximity sensor coil.

10. An electronic device according to claim 9, wherein the oscillation means comprises a phase-shift oscillator.

11. An electronic device according to claim 9, wherein the proximity sensor coil is a solenoid.

12. An electronic device according to claim 9, wherein the proximity sensor coil comprises a longitudinal axis, and wherein the proximity sensor coil is mounted such that the longitudinal axis of the proximity sensor coil is inclined relative to the face of a front cover.

13. An electronic device according to claim 9, wherein the electronic device is a mobile telephone.

14. A method of detecting proximity of an object relative to a loudspeaker with a loudspeaker coil which has an impedance, comprising the steps of:

supplying an audio signal to the loudspeaker coil,

supplying a radio frequency signal to the loudspeaker coil, and

providing a control signal responsive to a change in the impedance and indicative of whether an object is present in proximity of the device.

15. A method according to claim 14, wherein the method further comprises the step of:

detecting a change in frequency in an oscillator connected to the loudspeaker coil;

said frequency being responsive to the impedance of the loudspeaker coil.

16. A method according to claim 14, wherein the method further comprises the step of:

detecting a change in current flowing through the loudspeaker coil;

said current being responsive to the impedance of the loudspeaker coil.

17. An electronic device having a proximity sensor comprising:

communication means,

a proximity sensor adapted to provide a control signal indicative of whether an object is in the proximity of the device,

a proximity sensor coil with an impedance, and oscillation means coupled to the proximity sensor coil to provide the control signal in response to the impedance,

a loudspeaker having a loudspeaker coil, wherein the proximity sensor coil is integrated in the loudspeaker, wherein the device comprises a front cover made of a material allowing passage of magnetic lines of flux generated by the proximity sensor coil.