WO2000079769A1 - Dispositif et procede servant a detecter une proximite au moyen d'une antenne et a commander un haut-parleur - Google Patents

Dispositif et procede servant a detecter une proximite au moyen d'une antenne et a commander un haut-parleur Download PDF

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Publication number
WO2000079769A1
WO2000079769A1 PCT/SE2000/001324 SE0001324W WO0079769A1 WO 2000079769 A1 WO2000079769 A1 WO 2000079769A1 SE 0001324 W SE0001324 W SE 0001324W WO 0079769 A1 WO0079769 A1 WO 0079769A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
signal
loudspeaker
electronic device
communication
Prior art date
Application number
PCT/SE2000/001324
Other languages
English (en)
Inventor
Ulf Lindgren
Christian BJÖRK
Original Assignee
Telefonaktiebolaget Lm Ericsson (Publ)
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget Lm Ericsson (Publ) filed Critical Telefonaktiebolaget Lm Ericsson (Publ)
Priority to AU58639/00A priority Critical patent/AU5863900A/en
Publication of WO2000079769A1 publication Critical patent/WO2000079769A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/60—Substation equipment, e.g. for use by subscribers including speech amplifiers
    • H04M1/6033—Substation equipment, e.g. for use by subscribers including speech amplifiers for providing handsfree use or a loudspeaker mode in telephone sets
    • H04M1/6041—Portable telephones adapted for handsfree use
    • H04M1/605—Portable telephones adapted for handsfree use involving control of the receiver volume to provide a dual operational mode at close or far distance from the user
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M2250/00—Details of telephonic subscriber devices
    • H04M2250/12—Details of telephonic subscriber devices including a sensor for measuring a physical value, e.g. temperature or motion

Definitions

  • This invention relates to an electronic device providing wireless communication, comprising: an antenna, with an impedance, to radiate an electromagnetic field at radio frequencies; a communication circuit connected to the antenna to transmit and receive communication signals; a loudspeaker; and a proximity sensor to provide a control signal indicative of whether an object is in the proximity of the device.
  • Proximity sensors are widely used in telephones for activating various functions, for instance for switching between a handset mode and a speakerphone mode.
  • a relatively small loudspeaker in the handset is switched on and used in close contact with a user's ear, whereas a larger speaker is used in the speakerphone mode allowing other persons than the speaker to listen to a telephone conversation.
  • recent developments in small-sized loudspeakers for use in mobile communications devices have provided for use of high sound-pressure loudspeakers allowing the device to be used both in handset mode and speakerphone mode with a single small-sized high sound-pressure loudspeaker.
  • US patent No. 5,224,151 discloses a proximity sensor for use in a handset speakerphone and comprising an infrared range detection unit built into the handset for controlling switching between a handset mode and speakerphone mode .
  • US patent No. 5,337,353 discloses a capacitive proximity sensor comprising a guard electrode and a sensor electrode separated by an insulating layer. For example for controlling switching between a handset mode and speakerphone mode .
  • US patent No. 5,456,405 discloses a method and an apparatus for sensing proximity of an object using near-field effects. Radio frequency energy is fed to an antenna. The antenna radiates this radio frequency energy to charge an object in the near field of the antenna. When the posi- tion of the object changes, the impedance of the antenna changes. This impedance is detected to provide an indication of the movement of the object.
  • the sensing device may be mounted to detect the rotational velocity of a gear wheel with teeth.
  • the prior art poses the problem that the development of small-sized high sound pressure loudspeakers can lead to damages to a user's hearing if e.g. a phone is used like in handset mode, while the phone is actually in speakerphone mode. Thereby a high sound pressure may be emitted directly into a user's ear and cause damage. Further, since the small-sized loudspeakers are typically used in mobile handheld devices like for instance mobile telephones, small-sized inexpensive components is a must.
  • the electronic device mentioned in the opening paragraph is characterized in that the prox- i ity sensor is connected to the antenna to monitor the impedance of the antenna, to modify the control signal in response to changes of the impedance, and to control the volume of sound emitted by the loudspeaker.
  • the proximity sensor is very expedient in that a single antenna can be used for providing wireless communication as well as proximity de ⁇ tection.
  • the invention relates to a method, as stated in claim 10, of detecting whether an object is in the prox ⁇ imity of a communications device. Expedient embodiments of the method according to the invention will appear from the dependent claims 11-12.
  • fig. 1 shows an electronic device with a proximity sensor according to the invention
  • fig. 2 shows a cross-sectional view through an electronic device with a proximity sensor according to the invention
  • fig. 3 shows a first block diagram of a wireless communi- cations device comprising a proximity sensor
  • fig. 4 shows a second block diagram of a wireless communications device comprising a proximity sensor
  • fig. 5 shows a diagram of a decision unit
  • fig. 6 shows a block diagram of a circuit for controlling a loudspeaker.
  • FIG. 1 shows an electronic device with a proximity sensor according to the invention.
  • a mobile communications device 1 comprises a display 2 and a keypad 3 for operating the mobile communications device.
  • a front cover 6 is adapted to provide access to the display, the keypad, and a loudspeaker (not shown) and a microphone (not shown) .
  • the front cover 6 comprises openings 4 and 5 for transmission of sound to/from the loudspeaker and microphone, respectively.
  • the mobile communications device comprises an antenna 7.
  • Fig. 2 shows a cross-sectional view through an electronic device with a proximity sensor according to the invention.
  • the display 2, the keypad 3, a loudspeaker 11, a microphone 12, and the antenna 7 are connected to a printed circuit board (PCB) 9.
  • PCB printed circuit board
  • the device can be operated by battery power supplied by a battery 10.
  • Fig. 3 shows a first block diagram of a wireless communications device comprising a proximity sensor.
  • the device comprises a Radio Frequency power amplifier 301 adapted to amplify a communication signal Vc.
  • the amplified communication signal Vf is supplied to a port A of a directional coupler 302.
  • the directional coupler transmits the signal on the port A to a port B with a relatively small loss of power.
  • the communication signal transmitted from port the A to the port B is further transmitted to an im- pedance matching circuit 303.
  • the impedance matching circuit 303 is responsible for matching an input impedance of the antenna 304 against the impedance of the port B or a transmission line connected between the port B of the directional coupler and the impedance matching circuit.
  • the communication signal can be transmitted via the antenna 304 with a small loss of power.
  • the impedance matching circuit is tuned under a special operating condition.
  • the impedance adaptation circuit 303 is tuned to an operating condition corresponding to normal use, i.e. a situation where a user holds the phone m his hand close to his head/cheek/ear. This is preferred m order to conserve battery power and/or to provide a better transmission of the communication signal.
  • a part of the communication signal (Vf) supplied to the port A is transmitted to the port D of the directional coupler 302.
  • this signal is attenuated 20-30 dB relative to the signal input on the port A.
  • the power of the signal on the port D is indicative of the power of the signal on the port B.
  • the port D is connected to a power monitor PM 306 which is adapted to measure the transmitted power of the communication signal or at least a signal indicative of the transmitted power.
  • the impedance of the antenna 304 will change, all other things being equal.
  • the impedance adaptation circuit is not capable of matching the impedance between the port B of the directional coupler and the antenna 304.
  • the antenna will reflect a part Vr of the communication signal Vf .
  • the signal supplied to the antenna is denoted a forward communication signal and the reflected signal is denoted a reverse communication signal .
  • the directional coupler 302 provides a signal ⁇ Vr at a port C indicative of the reverse communication signal Vr.
  • ⁇ Vr is attenuated 20-30 dB relative to Vr .
  • the port C is connected to a power monitor PM 305 which is adapted to measure the transmitted power of the communication signal or at least a signal indicative of the transmitted power.
  • the signals Pr and Pf provided by the power monitor 305 and 306, respectively, are supplied to a decision unit 307.
  • the decision unit 307 is capable of calculating the ratio M between Pr and Pf . That is:
  • PSWR Power Standing Wave Ratio
  • Fig. 4 shows a second block diagram of a wireless communications device comprising a proximity sensor.
  • the communications device further comprises a receiver coupled to the antenna 404 via a switch 409.
  • the Radio Frequency power amplifier 401 is adapted to amplify a communication signal Vc and supply an amplified communication signal Vf to the antenna via the directional coupler 402, the switch 409, and the impedance matching circuit 403.
  • the switch is operated to switch between a transmitting mode (as shown) and a receiving mode. In receiving mode the switch is toggled to connect the antenna 404 to the receiver or preamplifier 410.
  • the communica- tions device is thus capable of providing wireless communication with other communication devices.
  • the communications device is thus a so-called transceiver.
  • the ports C and D of the directional coupler 402 are connected to the power monitors PM 405 and 406, respectively.
  • the decision unit 407 is adapted to calculate the ratio M:
  • the decision device is adapted to provide/modify a control signal Vctpr indicative of whether an object 408 is in the proximity of the antenna 404.
  • nominal communication frequencies are 900MHz, 1800MHz, 1900 MHz, and/or 2200 GHz.
  • the frequency band 890-915 MHz can be used for transmitting communication signals to a base station (not shown) ; and the frequency band 935-960 MHz can be used for receiving communication signals from the base station.
  • the directional coupler 402, the switch 409, the amplifiers 301, 401, and 401, as well as the other shown components are well-known components in the prior art.
  • Fig. 5 shows a diagram of a decision unit.
  • a signal Pf proportional to the power of the forward communication signal is supplied to a voltage divider circuit with resistors Rl and R2.
  • a circuit node connecting Rl and R2 is connected to a non-inverting input of a comparator 501 with a Schmitt-trigger function.
  • a signal Pr proportional to the power of the reverse communication signal is supplied to an inverting input of the comparator 501.
  • Fig. 6 shows a block diagram of a circuit for controlling a loudspeaker.
  • the circuit is typically connected to a radio frequency (RF) amplifier providing a received communications signal.
  • the RF amplifier may be the amplifier 410 shown in fig. 4 with its output connected to a ter i- nal 604 of a demodulator 601.
  • the demodulator 601 extracts an audio/voice signal in the received communications signal.
  • the audio/voice signal is supplied to an audio amplifier 602 for driving a loudspeaker 603 to reproduce the audio/voice signal acoustically.
  • the amplifier has a gain control input terminal 605.
  • the control signal Vctpr indicative of whether an object is in proximity of the antenna (that is, thereby, the electronic device e.g. a mobile telephone) is applied to this gain control input terminal 605.
  • the volume of the loudspeaker can be controlled by limiting the amplitude of the au- dio/voice signal, by limiting the gain of the amplifier 602, etc.
  • the loudspeaker is typically a small-sized loudspeaker with a diameter less than 30 to 40 mm capable of providing a sufficiently high sound pressure to reproduce voice recognizable by a human within a radius up to about 5 metres, preferably up to 2 metres.
  • a handset mode is defined as a mode of operation where the loudspeaker of the device emits sound di- rectly into a user's ear at a relatively low volume (sound pressure) .
  • a speakerphone mode is defined as a mode of operation where the loudspeaker emits sound into a space for perception by an audience at a relatively high volume (sound pressure) .
  • the invention has been described in connection with a mobile telephone, it may be applied in similar devices such as other communications devices, laptop computers, portable music playing devices, etc., where the detection of the proximity of an object relative to the device is of interest for the control of certain functions of the device, such as on/off-, standby/on-switching, control of display illumination, volume control of a loudspeaker, etc.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Transceivers (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Telephone Function (AREA)

Abstract

Dispositif électronique (par exemple, un téléphone mobile) permettant d'effectuer une communication sans fil et comprenant : une antenne (7, 304, 404) pourvue d'une impédance, afin d'assurer le rayonnement d'un champ électromagnétique à des radiofréquences ; un circuit de communication (301, 401) relié à l'antenne (7, 303, 404) afin d'émettre et de recevoir des signaux de communication ; un haut-parleur (11, 603) et un capteur de proximité (302, 305, 306, 307, 402, 405, 406, 407) servant à produire un signal de commande (Vctpr) indiquant si un objet (408) se trouve à proximité du dispositif. Ce dernier est caractérisé par le fait que le capteur de proximité est relié à l'antenne (76, 303, 404) afin de contrôler l'impédance de celle-ci, de modifier le signal de commande (Vctpr) en réaction à des changements de l'impédance et de commander le volume sonore émis par le haut-parleur (11, 603). On peut, de ce fait, utiliser une seule antenne à la fois pour effectuer une communication sans fil de signaux vocaux et/ou de signaux de données, par exemple, tandis qu'on met en application cette antenne afin de détecter la présence d'un objet à proximité de l'antenne, ce qui permet d'éviter un préjudice causé à l'ouïe sous l'effet d'une pression sonore élevée. L'invention concerne également un procédé servant à détecter si un objet se trouve à proximité d'un dispositif de communication.
PCT/SE2000/001324 1999-06-21 2000-06-20 Dispositif et procede servant a detecter une proximite au moyen d'une antenne et a commander un haut-parleur WO2000079769A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU58639/00A AU5863900A (en) 1999-06-21 2000-06-20 Apparatus and method of detecting proximity by means of an antenna, and controlling a loudspeaker

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9902341A SE9902341L (sv) 1999-06-21 1999-06-21 Apparat och förfarande för att detektera närhet med hjälp av en antenn
SE9902341-8 1999-06-21

Publications (1)

Publication Number Publication Date
WO2000079769A1 true WO2000079769A1 (fr) 2000-12-28

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PCT/SE2000/001324 WO2000079769A1 (fr) 1999-06-21 2000-06-20 Dispositif et procede servant a detecter une proximite au moyen d'une antenne et a commander un haut-parleur

Country Status (3)

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AU (1) AU5863900A (fr)
SE (1) SE9902341L (fr)
WO (1) WO2000079769A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002102036A1 (fr) * 2001-06-13 2002-12-19 Siemens Aktiengesellschaft Telephone mobile
GB2382241A (en) * 2001-11-07 2003-05-21 Sendo Int Ltd Controlling the volume of a speaker in response to the proximity to an object
WO2005013587A1 (fr) * 2003-08-01 2005-02-10 Research In Motion Limited Systeme et procede de reglage automatique fiable du volume sonore pour un fonctionnement mains libres
EP1589784A2 (fr) * 2004-04-21 2005-10-26 Siemens Audiologische Technik GmbH Prothèse auditive avec dispositif de commande
US7006041B2 (en) * 2003-07-25 2006-02-28 Ntt Docomo, Inc. Radio receiver, radio transmitter and impedance control method
US7196316B2 (en) 2004-09-22 2007-03-27 Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. Portable electronic device with activation sensor
GB2464868A (en) * 2004-09-22 2010-05-05 Avago Tech Ecbu Ip Folding telephone with hinge based open/closed proximity detector
GB2515830A (en) * 2013-07-05 2015-01-07 Broadcom Corp Method and apparatus for use in a radio communication device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5224151A (en) * 1992-04-01 1993-06-29 At&T Bell Laboratories Automatic handset-speakephone switching arrangement for portable communication device
EP0827287A2 (fr) * 1996-08-30 1998-03-04 Nokia Mobile Phones Ltd. Système d'alarme pour un téléphone portatif

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5224151A (en) * 1992-04-01 1993-06-29 At&T Bell Laboratories Automatic handset-speakephone switching arrangement for portable communication device
EP0827287A2 (fr) * 1996-08-30 1998-03-04 Nokia Mobile Phones Ltd. Système d'alarme pour un téléphone portatif

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002102036A1 (fr) * 2001-06-13 2002-12-19 Siemens Aktiengesellschaft Telephone mobile
GB2382241A (en) * 2001-11-07 2003-05-21 Sendo Int Ltd Controlling the volume of a speaker in response to the proximity to an object
GB2382241B (en) * 2001-11-07 2006-08-09 Sendo Int Ltd Speaker volume control means and method of operation
US7006041B2 (en) * 2003-07-25 2006-02-28 Ntt Docomo, Inc. Radio receiver, radio transmitter and impedance control method
WO2005013587A1 (fr) * 2003-08-01 2005-02-10 Research In Motion Limited Systeme et procede de reglage automatique fiable du volume sonore pour un fonctionnement mains libres
EP1589784A2 (fr) * 2004-04-21 2005-10-26 Siemens Audiologische Technik GmbH Prothèse auditive avec dispositif de commande
EP1589784A3 (fr) * 2004-04-21 2006-01-25 Siemens Audiologische Technik GmbH Prothèse auditive avec dispositif de commande
US7561708B2 (en) 2004-04-21 2009-07-14 Siemens Audiologische Technik Gmbh Hearing aid
US7196316B2 (en) 2004-09-22 2007-03-27 Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. Portable electronic device with activation sensor
GB2464642A (en) * 2004-09-22 2010-04-28 Avago Tech Ecbu Ip Automatic speakerphone/handset mode selection in a flip phone
GB2464868A (en) * 2004-09-22 2010-05-05 Avago Tech Ecbu Ip Folding telephone with hinge based open/closed proximity detector
GB2464868B (en) * 2004-09-22 2010-06-16 Avago Tech Ecbu Ip Folding telephone
GB2515830A (en) * 2013-07-05 2015-01-07 Broadcom Corp Method and apparatus for use in a radio communication device

Also Published As

Publication number Publication date
SE9902341D0 (sv) 1999-06-21
SE9902341L (sv) 2001-02-21
AU5863900A (en) 2001-01-09

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