Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
1998-06-05
2001-11-13
Hunter, Daniel (Department: 2684)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
C455S566000
Reexamination Certificate
active
06317614
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a mobile communication terminal (e.g. a portable phone, a radio communication apparatus, or a mobile phone). More particularly, the invention relates to a control circuit which reduces the consumption of current by a hand-held mobile communication terminal.
BACKGROUND OF THE INVENTION
A typical example of a mobile communication terminal is a mobile phone. A mobile phone generally contains a display portion (e.g. a liquid crystal display (LCD)) to display information such as telephone numbers or an operational state of the phone so that a user can view such information. Also, in a conventional mobile phone, the display portion is driven by a display drive circuit which is operatively coupled to a power supply switch. When the power supply switch is turned ON to supply power to various components of the mobile phone, the display drive circuit continuously and constantly drives the display portion to display information. Also, the display drive circuit only stops driving the display portion when the power supply switch is turned OFF.
Usually, the mobile phone contains a microphone and a speaker which are provided on a handset housing. Also, the display portion is generally provided on the handset housing in an area between the microphone and the speaker. Therefore, when a user holds the mobile phone to the side of his or her face during a telephone conversation, the user cannot see the information that is displayed on the display portion. However, since the display portion is constantly driven by the display drive circuit when the mobile phone is turned ON, the display portion and display drive circuit unnecessarily consume a substantial amount of current.
In order to attempt to solve the problem above, a mobile telephone is disclosed in Japanese Patent Laid-open Publication No. Hei 7-170226. The mobile phone has an ear-piece portion which is located near the speaker of the mobile phone and a pressure sensor which is coupled to the ear-piece portion. When the ear-piece portion is brought into contact with a user's ear during a telephone conversation, the pressure sensor detects the pressure applied by the user's ear on the ear-piece portion and instructs the display drive circuit to stop driving the display portion. However, the pressure sensor is relatively expensive, and thus, incorporating such sensor into the mobile phone substantially increases the cost of the phone and makes the structure of the phone complicated. Also, in order for the pressure sensor to properly turn OFF the display, the ear-piece portion must remain in contact with the user's ear during the entire conversation. However, when the user's ear is slightly removed from the ear-piece portion (e.g. when the volume of the sound being received by the phone is high), the pressure sensor does not detect any pressure, and the display is not turned OFF. Therefore, the phone may still consume power unnecessarily.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a mobile communication terminal which stops the operation of a display portion when a user can not view the information displayed on the display portion in order to reduce the unnecessary current consumption.
In order to achieve the above and other objects, a mobile communication terminal is provided. The mobile communication terminal comprises: a microphone which receives a sound and outputs a corresponding input sound signal; a microphone amplifier which inputs said input sound signal, which amplifies said input sound signal to produce an amplified sound signal when set in an ON state, and which does not produce said amplified sound signal when set in an OFF state; a display which displays information; a display drive circuit which drives said display to display said information; and a control circuit which is operably connected to said microphone amplifier and said display drive circuit, wherein said control circuit selectively sets said microphone amplifier in said ON state and said OFF state, wherein said control circuit instructs said display drive circuit not to drive said display when said microphone amplifier is set in said ON state, and wherein said control circuit controls said display drive circuit to drive said display when said microphone amplifier is set in said OFF state.
REFERENCES:
patent: 5586182 (1996-12-01), Miyashita
patent: 5752195 (1998-05-01), Tsuji et al.
patent: 5794137 (1998-08-01), Harte
patent: 5881377 (1999-03-01), Giel
patent: 5970419 (1999-10-01), Terashima
patent: 6055441 (2000-05-01), Wieand
patent: 797310 A2 (1997-09-01), None
patent: 5-227263 (1993-09-01), None
patent: 7-170226 (1995-07-01), None
patent: 7-336417 (1995-12-01), None
Corsaro Nick
Hunter Daniel
NEC Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
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