Proximity sensor, in particular microphone for reception of sound signals in the human audible sound range, with ultrasonic proximity estimation

• US 8,401,513 B2
• Filed: 07/01/2010
• Issued: 03/19/2013
• Est. Priority Date: 07/02/2009
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Langereis, Geert, van Lippen, Twan, Dirksen, Peter, Pasveer, Frank
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US12/828,482
• Publication Number:
  US 20110003614A1
• Time in Patent Office: 992 Days
• Field of Search: 455/401, 455/569.1, 455/569.2, 455/550.1, 381/369, 381/174, 367/118, 367/87, 367/95, 367/96, 367/99, 379/418, 379/419, 37942001-42004
• US Class Current: 455/401
• CPC Class Codes: G01S 15/06 Systems determining the position data of a target
• CPC Class Codes: G01S 15/876 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S15/872 takes precedence
• CPC Class Codes: H03K 17/94 characterised by the way in which the control signals are generated
• CPC Class Codes: H03K 2217/94005 activated by voice or sound
• CPC Class Codes: H04M 1/6016 in the receiver circuit
• CPC Class Codes: H04M 1/72454 according to context-related or environment-related conditions
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2400/01 Transducers used as a loudspeaker to generate sound aswell as a microphone to detect sound

Abstract

Proximity sensor, particularly for usage in an electronic mobile device, comprising at least one acoustic transducer adapted for receiving acoustic signals at least in parts of the frequency range of human audible sound and emitting and/or receiving ultrasonic signals for proximity estimation. The acoustic transducer preferably is a Micro-Electro-Mechanical-Systems (MEMS) microphone. Further, a method in an electronic device comprising an acoustic transducer is provided comprising the steps of generating at least one electric signal in the frequency range of ultrasonic sound, emitting at least one ultrasonic signal by means of the acoustic transducer; receiving at least one ultrasonic signal by means of the acoustic transducer; deducing from the at least one emitted ultrasonic signal and the at least one received ultrasonic signal at least the delay between emission of the emitted ultrasonic signal and reception of the corresponding ultrasonic signal.

Claims

1. A proximity sensor comprising:

at least one acoustic transducer configured to emit at least one ultrasonic signal, receive acoustic signals at least in a portion of a frequency range of human audible sound, receive at least one reflected ultrasonic signal, separate the received acoustic signals from the at least one received ultrasonic signal, and perform proximity estimation, wherein the proximity sensor is operable to deduce from both the at least one emitted ultrasonic signal and the at least one received ultrasonic signal at least a delay between emission of the at least one emitted ultrasonic signal and reception of the at least one received ultrasonic signal.

2. The proximity sensor according to claim 1, wherein the acoustic transducer comprises one of a capacitive and an electrostatic microphone.

3. The proximity sensor according to claim 1, wherein the acoustic transducer comprises a Micro-Electro-Mechanical-Systems (MEMS) microphone.

4. The proximity sensor according to claim 1, wherein the acoustic transducer has a resonance frequency in a frequency range of ultrasound.

5. A proximity sensor arrangement, comprising:

at least one power amplifier;

at least one diplexer unit;

at least one processor configured to provide an electric signal in the ultrasonic frequency range,

a comparison unit configured to compare the received ultrasonic signals to the provided electric signal at least regarding delay and amplitude, and determine a correlation of the received ultrasonic signals and the provided electric signal; and

at least one acoustic transducer as defined in claim 1.

6. The proximity sensor arrangement according to claim 5, further comprising:

a second acoustic transducer, wherein the at least one processor is further configured to evaluate signals received by the first and second acoustic transducers regarding a spatial direction the signals are received from.

13. A mobile phone comprising the proximity sensor according to claim 1.

15. A mobile phone comprising the proximity sensor arrangement according to claim 5.

16. The proximity sensor according to claim 1, wherein the acoustic transducer has a resonance frequency in a frequency range between 50 kHz and 150 kHz.

17. The proximity sensor according to claim 1, wherein the acoustic transducer has a resonance frequency in a frequency range between 100 kHz and 120 kHz.

7. A method of proximity estimation in an electronic device having an acoustic transducer, the method comprising:

generating at least one electric signal in a frequency range of ultrasonic sound;

the acoustic transducer emitting at least one ultrasonic signal by the acoustic transducer;

the acoustic transducer receiving both the emitted at least one ultrasonic signal and acoustic signals in a portion of a frequency range of human audible sound;

separating the received at least one ultrasonic signal from the received acoustic signals; and

deducing from the emitted at least one ultrasonic signal and the received at least one ultrasonic signal a delay between emission of the emitted at least one ultrasonic signal and reception of the received at least one ultrasonic signal.

8. The method according to claim 7, wherein said generating further comprises:

generating an electric signal, a frequency of which corresponds to an acoustic resonance frequency of the acoustic transducer.

9. The method according to claim 7, wherein said deducing further comprises:

determining whether the received at least one ultrasonic signal correlates with the emitted at least one ultrasonic signal; and

estimating a distance of the electronic device from a time lag between emission of the emitted at least one ultrasonic signal and reception of the correlating at least one ultrasonic signal.

10. The method according to claim 7, wherein said deducing further comprises:

evaluating differences of the amplitudes of the emitted at least one ultrasonic signal and the correlating at least one ultrasonic signal.

11. The method according to claim 7, wherein said deducing further comprises:

signaling whether a time lag between emission and reception of the respective at least one ultrasonic signals are above and/or are below a predefined threshold value.

12. The method according to claim 7, wherein the method further comprises:

splitting a received signal in a predefined part substantially located in the frequency range of human audible sound and in a predefined part located in the ultrasonic frequency range comprising the ultrasonic signal.

14. A computer program product, embodied on a non-transitory, computer-readable medium, comprising instructions adapted to cause a programmable processor, when executed on the programmable processor, to perform the steps of the method according to claim 7.