JP3619536B2 - Cordless telephone - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a cordless communication device, and more specifically to howling prevention.
[0002]
[Prior art]
For example, in a cordless telephone in which a parent device and a child device are wirelessly connected, the parent device is used as a base device and the child device is used as a handy device at hand. As shown in FIG. 3, the handset 1 that is generally not in use (standby) is placed on the charger 2, and the handset 1 is connected via a charging terminal 2 a provided on the charger 2. The battery is connected to the built-in battery to charge the battery.
[0003]
When the handset 1 is picked up from the charger 2, it automatically enters an off-hook state and a communication circuit (external / internal) is formed. On the other hand, when the handset 1 is set in the charger 2, the charging terminal 2a is connected to the handset. The communication circuit can be disconnected by detecting conduction with a charging terminal (not shown) provided in FIG. The communication circuit can be turned on / off by operating a switch of a button operation unit provided in the slave unit 1.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional apparatus, when the handset 1 is set close to the charger 2 after the call is finished, the speaker 1a of the handset 1 wraps around the microphone 1b due to reflection on the opposite surface of the charger 2 And sometimes howling.
[0005]
On the other hand, a proximity sensor composed of a Hall element or the like is mounted in the slave unit 1, and the proximity sensor detects that the distance between the slave unit 1 and the charger 2 has approached the above-mentioned howling distance, and a communication circuit. It is also conceivable to complete the process. However, with such a configuration, a separate detection circuit such as a proximity sensor must be additionally provided, and means for operating the proximity sensor must also be installed on the charger 2 side. The size is increased, resulting in high costs.
[0006]
The present invention has been made in view of the above-described background. The object of the present invention is to solve the above-described problems and to provide a cordless communication device such as a handset as a charger with a simple and small structure. An object of the present invention is to provide a cordless communication device capable of detecting the approach and disconnecting a communication circuit or suppressing howling.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, in the cordless communication device according to the present invention, a voice detection unit, a voice output unit and a radio unit driven by an internal battery, and a charger for charging the internal battery are provided. A cordless communication device comprising: a detection coil capable of detecting a magnetic flux generated from an excitation coil; and a charging means for charging the internal battery based on an induced electromotive force generated in the detection coil by electromagnetic induction, The detection unit detects power and detects that the cordless communication device has approached the charger, and the disconnection unit disconnects the output of the voice detection unit based on the detection result of the detection unit.
[0008]
Preferably, the detection means comprises a comparator having the output voltage of the detection coil as an input, and more preferably, the reference voltage of the comparator is set higher than the voltage required for charging the internal battery. Set it low.
[0009]
More preferably, the disconnecting means is at least one of a switch that reduces the sensitivity of the sound detecting means or disconnects the output of the sound detecting means from another circuit.
[0010]
[Action]
After the end of a predetermined call, when trying to set the communication device to the charger and approaching to some extent before approaching completely (approaching the distance that causes howling), the magnetic flux generated from the excitation coil passes through the detection coil, An induced electromotive force is generated in the detection coil. Therefore, when the induced electromotive force is detected by the detecting means, the output of the sound detecting means is cut off. This prevents howling.
[0011]
Further, when the detection means is constituted by a comparator, the communication device can easily be within a certain distance range depending on whether or not the value of the induced electromotive force (voltage) generated in the detection coil exceeds a predetermined reference value. You can know if you have come. Moreover, when the reference value is set lower than the voltage required to charge the internal battery, it is detected even when the charger and the communication device are relatively far apart (as far as the normal call state is not far). It is possible to reliably suppress the occurrence of howling.
[0012]
Further, if the disconnecting means is at least one of the switches for reducing the sensitivity of the sound detecting means or disconnecting the output of the sound detecting means from other circuits, in any case, the sound generating means wraps around the sound detecting means. The accompanying howling is more reliably suppressed.
[0013]
【Example】
Hereinafter, preferred embodiments of a cordless communication apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a preferred embodiment of the present invention. As shown in the figure, in the slave unit 10, a microphone 11 serving as a voice detection unit and a speaker 12 serving as a voice output unit are connected to a radio circuit 13 serving as a communication unit, and the master unit is connected via an antenna 14 connected to the radio circuit 13. And a telephone call on a predetermined line (external line / internal line). Each unit 11 to 13 operates by receiving power supply from the battery 15.
[0014]
Here, in the present invention, the battery 15 built in the slave unit 10 is first charged by a non-contact charging method using electromagnetic induction. That is, the charger 18 is provided with an exciting coil 20 at a predetermined internal position, and by attaching the power cable 21 connected to the exciting coil 20 to the commercial power source 22, the commercial power source 22 exchanges the exciting coil 20 with AC. Power is supplied.
[0015]
Then, the AC magnetic field generated by the excitation coil 20 is detected by the detection coil 24 built in the slave unit 10, and AC power is generated at both ends of the detection coil 24 by electromagnetic induction. Therefore, a rectifier circuit 25 composed of a diode bridge is connected between both terminals of the detection coil 24, and the battery 15 is connected to the output of the rectifier circuit 25 via a backflow prevention diode 26. As a result, when the handset 10 is set on the charger 18, the excitation coil 20 and the detection coil 24 come close to each other and face each other, an electromotive force is generated in the detection coil 24 by electromagnetic induction, and the battery 15 is charged. . The rectifier circuit 25, the backflow prevention diode 26, and the like constitute charging means.
[0016]
Further, as shown in FIG. 2, the exciting coil 20 is wound around the trunk portion of the U-shaped core 28 by a predetermined number of turns, and a recess 29 provided at one end of the upper surface of the charger 18 together with the core 28. The both ends 28a of the core 28 are filled so as to be located on the side of the recess 29 along the inner surface. And the periphery is resin-molded.
[0017]
On the other hand, when the handset 10 is set in the charger 18, the receiving portion 10a in which the speaker of the handset 10 is set is inserted and disposed in the recess 29, and the detection coil 24 is placed in the receiving portion 10a. Is implemented. That is, the detection coil 24 is also wound around the trunk portion of the U-shaped core 30 by a predetermined number of turns so that the tip 30a of the core 30 faces the tip 28a of the core 28 around which the exciting coil 20 is wound. In addition, the metal plate 32 is disposed so as to cover the periphery of the core 30 and is magnetically shielded. Thereby, the magnetic field emitted from the excitation coil 20 and received by the detection coil 24 does not affect other circuits mounted on the slave unit 10.
[0018]
Although a specific configuration is omitted, a predetermined overcharge prevention circuit for preventing overcharging of the battery 15 and a function of automatically connecting a communication line when the handset 10 is removed from the charger 18 It also has.
[0019]
In the present invention, the output of the rectifier circuit 25 is branched and input to one input terminal of the comparator 32 as detection means. The reference voltage Vs is applied to the other input terminal of the comparator 32. When the output of the rectifier circuit 25 exceeds the reference voltage Vs, the output of the comparator 32 becomes H, and the contact of the normally closed switch 34 serving as a disconnecting means connected to the microphone 11 is adjusted to be opened. When the normally closed switch 34 is opened, the communication circuit is cut off (no wraparound from the speaker 12 to the microphone 11).
[0020]
Next, the operation of the above embodiment will be described. First, in a normal call state, since the handset 10 and the charger 18 are separated from each other, the magnetic force generated from the excitation coil 20 does not pass through the detection coil 24, and the battery 15 is not charged without electromagnetic induction. I will not. Although not shown, power is supplied from the battery 15 to each circuit in the slave 10 through a predetermined path. Since the output of the comparator 32 is also L, the contact of the normally closed switch 34 is closed. Therefore, the slave unit 10 can communicate with a master unit (not shown) using a known mechanism, and can perform an extension call or an outside call.
[0021]
On the other hand, after a predetermined call is finished, an attempt is made to set the handset 10 on the charger 18, and at this time, if it approaches to some extent (closer to a distance that causes howling) before it is completely set, it emits from the exciting coil 20. The generated magnetic flux passes through the detection coil 24, and the output of the rectifier circuit 25 becomes a certain voltage (Vs) or more. Then, the comparator 32 detects the output voltage, outputs a prohibition signal (H), and opens the contact of the normally closed switch 34. Therefore, the microphone 11 is disconnected from the circuit, and howling due to wraparound from the speaker 12 is suppressed. Then, by appropriately setting the reference voltage Vs, the prohibition signal can be generated even if the output of the rectifier circuit 25 is insufficient to charge the battery 15.
[0022]
In the above-described embodiment, the example in which the status switch 34 connected in series to the output of the microphone 11 is used as the cutting means has been described. However, the present invention is not limited to this, for example, to the output (prohibition signal) of the comparator. Based on this, the communication line itself may be disconnected (operation stop / power off), or the sensitivity of the microphone 11 may be lowered to such an extent that no howling occurs. When the sensitivity of the microphone 11 is lowered, for example, a mechanism that automatically disconnects the communication circuit when the slave unit is set in the charger is provided by a mechanism similar to the conventional method. desirable.
[0023]
Further, in the above-described embodiment, the example applied to the cordless phone slave unit has been described, but the present invention is not limited to this, and in the case where the handset of the master unit is also cordless, The present invention can also be applied to the parent device, and can also be applied to a mobile phone or other cordless communication device.
[0024]
【The invention's effect】
As described above, in the cordless communication device according to the present invention, when the communication device is set in the charger, it is emitted from the exciting coil when approaching to some extent (approaching a distance that causes howling) before being completely set. Since an induced electromotive force is generated in the detection coil by electromagnetic induction based on the magnetic flux, the cutting means can be operated by detecting it by the detecting means, and at least the output of the sound detecting means can be cut off. The sound does not circulate from the means to the sound detecting means side, and howling can be prevented.
[0025]
And since the induced electromotive force shares a mechanism for charging the internal battery, the structure is simple and small. In addition, since it is only necessary to detect that the communication device has approached the charger, whether or not it is approaching even if the induced electromotive force that is relatively far away and is insufficient to charge both ends of the detection coil is generated. Therefore, it is possible to accurately detect approaching a predetermined distance that causes howling. In particular, if a comparator is used as the detection means, such an effect can be easily achieved by appropriately setting the reference voltage.
[0026]
In addition, when charging the battery, electromagnetic induction is used, so there is no need to provide a charging terminal on the charger and communication device, and there is no exposed part, so there is no contact failure due to rust or dust adhesion. Reliable charging can be performed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a cordless telephone handset and a charger as an embodiment of a cordless telephone device according to the present invention.
FIG. 2 is a cutaway sectional view showing a part of the slave unit and the charger of the present embodiment.
FIG. 3 is a perspective view showing an example of a conventional slave unit and a charger.
[Explanation of symbols]
10 cordless handset (cordless telephone)
11 Microphone (voice detection means)
12 Speaker (Audio output means)
13 Radio circuit (communication means)
15 Battery 18 Charger 20 Excitation coil 24 Detection coil 25 Rectifier circuit (charging means)
26 Backflow prevention diode (charging means)
32 comparator (detection means)
34 Normally closed switch (cutting means)

Claims (4)

Voice detection means, voice output means and radio means driven by an internal battery;
A detection coil capable of detecting a magnetic flux emitted from an excitation coil provided in a charger for charging the internal battery;
A cordless communication device comprising charging means for charging the internal battery based on an induced electromotive force generated in the detection coil by electromagnetic induction,
Detecting means for detecting the induced electromotive force and detecting that the cordless communication device approaches the charger;
A cordless communication apparatus comprising: a disconnecting unit that disconnects at least an output of the voice detecting unit based on a detection result of the detecting unit. The cordless call device according to claim 1, wherein the detection means is a comparator that receives an output voltage of the detection coil. The cordless call device according to claim 2, wherein a reference voltage of the comparator is set lower than a voltage necessary for charging the internal battery. The said cutting | disconnection means is at least one of the switches which reduce the sensitivity of the said audio | voice detection means, or isolate | separate the output of the said audio | voice detection means from another circuit, The any one of Claims 1-3 characterized by the above-mentioned. Cordless call device.

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