JPH04185145A - Hand-free telephone set - Google Patents

Abstract

PURPOSE:To weaken the acoustic coupling between a speaker and a microphone and to eliminate a speech head interrupt by placing a handset upright white its receiver is directed upward and its transmitter is directed downward so as to attain both the handset talking while a telephone set is lifted up and the handset talking while the telephone set is hooked on. CONSTITUTION:Talking is implemented by using a receiver 11 and a microphone 12 in the case of handset talking when the telephone set is put in hand. In the case of hand-free talking where the telephone set is placed on a desk or the like, the switch operation is executed to switch the receiver 11 to a speaker 13 and the speaker 13 to a directivity microphone 14 and the speaker 13 and the directivity microphone 14 are used for talking. In this case, the speaker 13 is fitted to the lower part of the handset and the directivity microphone 14 is set to the upper part of the handset. Thus, the distance of the both is taken large. Thus, the acoustic coupling between the speaker and the microphone is weakened to realize the hand-free telephone set with excellent talking quality without a speech head interrupt.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hands-free telephone that realizes a high-quality hands-free calling function in a handset-type telephone.

2. Description of the Related Art In recent years, cordless telephones have become widespread, and small handset-type telephones such as cordless handsets have become commonplace. In order to further enhance the mobility of this cordless phone, there is a hands-free phone that has a hands-free calling function added to the cordless phone.

An example of the above-mentioned conventional hands-free phone call will be described below with reference to the drawings.

FIG. 3 shows how the speaker and microphone are installed in a conventional cordless telephone with a hands-free function, and FIG. 3a shows a side view, and FIG. 3a shows a front view thereof.

In Fig. 3, 1 is a receiver for handset calls;
3 is an omnidirectional microphone used both as a transmitter for handset calls and for collecting sound for hands-free calls, and 3 is a speaker for hands-free calls.

The operation of the conventional hands-free telephone configured as described above will be described below.

First, when making a handset call while holding the telephone in hand, the telephone receiver 1 and microphone 2 are used to make a telephone call.

Next, when a hands-free call is to be made while the telephone is placed on a desk or the like, the handset 1 is switched to the speaker 3 by a switch operation, and the call is made using the speaker 3 and the microphone 2.

In a hands-free call state, the speaker volume and microphone sensitivity are set higher than in a handset call, so if they are left as they are, feedback will occur and it will be impossible to make a call.

Therefore, in hands-free telephones, when a receive signal is detected during a hands-free call, the sensitivity of speaker 3 is set to high (lower the sensitivity of microphone 2), and when a transmit signal is detected, the sensitivity of speaker 3 is set to high. Adjust the gain so that the sensitivity of microphone 2 is low and high.
Prevents howling.

In a hands-free call state, the speaker volume and microphone sensitivity are set higher than in a handset call. Therefore, if the speaker for hands-free calls is also used as the receiver 1 for handset calls, there is a risk that the loud volume will hurt your ears if you mistake the hands-free call for a handset call and put the receiver to your ear. Therefore, in a hands-free telephone, a speaker 3 dedicated to hands-free calls is provided in addition to a receiver 1 for handset calls.

Problems to be Solved by the Invention However, the above configuration has a problem in that the acoustic coupling between the speaker 3 and the microphone 1 is strong, and the voice switch malfunctions, causing the beginning of the speech to be cut off.

In view of the above-mentioned problems, the present invention provides a hands-free telephone that reduces the acoustic coupling between a speaker and a microphone, and provides good call quality without cutting off the beginning of a conversation.

Means for Solving the Problems In order to solve the above problems, the hands-free telephone of the present invention has a speaker for hands-free calls at the bottom of the handset, and a hands-free phone on the upper side of the handset, in addition to the speaker and microphone for handset calls. It is equipped with a directional microphone for free calls.

Effect of the Invention With the above-described configuration, the present invention can increase the distance between the speaker and the microphone to significantly weaken the acoustic coupling between the two, thereby enabling hands-free calls with good call quality without disconnection at the beginning of the conversation.

Example Below, regarding a hands-free telephone according to an example of the present invention,
This will be explained with reference to the drawings.

FIG. 1 shows the configuration of a hands-free telephone according to an embodiment of the present invention. In FIG. 1, 11 is a receiver for handset calls, 12 is an omnidirectional microphone for handset calls, 13 is a speaker for hands-free calls, 14 is a directional microphone for hands-free calls, and 15 is a punching metal. Further, the weight balance and the shape of the bottom surface 17 of the housing 16 are determined so that the housing 16 can be installed in an upright state with the receiver 11 on top and the transmitter of the omnidirectional microphone 12 on the bottom.

Regarding the hands-free phone configured as above,
The operation will be explained below using FIG.

First, when making a handset call while holding the phone in your hand,
A telephone conversation is made using a receiver 11 and a microphone 12. Next, when the telephone is placed on a desk or the like and a hands-free call is to be made, the handset 11 is switched to the speaker 13 and the microphone 12 is switched to the directional microphone 14 by a switch operation, and the call is made using the speaker 13 and the directional microphone 14.

In this hands-free call state, a voice switch (not shown) switches the speaker 1 when an incoming signal is detected.
3, the sensitivity of the directional microphone 14 is low,
When a transmission signal is detected, the gain is adjusted to lower the sensitivity of the speaker 13 and increase the sensitivity of the directional microphone 14, thereby preventing howling.

Here, since the acoustic coupling between the speaker and the microphone is determined by the distance and directivity, the directional microphone for hands-free calling needs to be installed in a place that is far from the speaker 13 and can easily exhibit the directional effect. . In this embodiment, the speaker 13 is attached to the bottom of the handset and the directional microphone 14 is attached to the top of the microphone, so that a large distance can be maintained between the two, and the acoustic coupling between the two can be weakened.

In this type of noise-free phone, which is installed upright, the top of the handset is the place where the directivity is less affected by the desk or floor, and the sound waves from the speaker 13 installed at the bottom of the handset are transmitted to the phone. Since the location where the signal propagates undisturbed is the side of the handset, the top side of the handset is the most preferred location for mounting the directional microphone. Therefore, if a unidirectional microphone is installed as the directional microphone 14 toward the speaker's position in the upper front direction, the speaker will have high sensitivity and the speaker 13 will have low sensitivity.
4 and the speaker 13 can be weakened.

If a bidirectional microphone is mounted forward as the directional microphone 14, the speaker 13 can be directed to the 90'' direction, which has the lowest sensitivity, and the acoustic coupling can be further weakened.

Even if a unidirectional microphone is mounted upward as the directional microphone 14, the speaker 13 can be directed to the 180° direction where it has the lowest sensitivity, and the acoustic coupling is weakened. In this case, it becomes non-directional in the horizontal plane, and can also be used for conversations with multiple speakers surrounding the phone.

As described above, according to this embodiment, in addition to the speaker and microphone for handset calls, a speaker for hands-free calls is provided at the bottom of the handset, and a directional microphone for hands-free calls is provided on the upper side of the handset. , it is possible to significantly weaken the acoustic coupling between the speaker and the microphone, and it is possible to realize a hands-free call with good call quality without cutting off the beginning of the conversation.

A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of a hands-free telephone according to a second embodiment of the present invention, and FIG. 2a is a side view thereof, and FIG. 2A is a front view thereof.

In the figure, 21 is a speaker for hands-free calling;
22 is an acoustic tube, 23 is a sound hole, and the other structures are the same as those shown in FIG.

The only difference from the configuration shown in FIG. 1 is the speaker for hands-free calling, and this part will be explained below.

The speaker 21 does not open directly to the outside, but is attached to one end of the acoustic tube 22, and the other end of the acoustic tube 22 is connected to the sound hole 23. Sound from the speaker 21 is radiated from the sound hole 23 via the sound tube 22. Speaker 21 and microphone 14
The acoustic coupling is determined by the distance between the sound hole 23 and the microphone 14 and the directivity of the microphone. If you install the speaker by opening it directly to the outside, avoiding the circuit board, battery, or dial panel, the mounting position will be limited and it will not be possible to install it based on acoustic coupling. A method that radiates sound by guiding it to a location where there is less coupling allows for a design that weakens acoustic coupling without forcing major changes to the design.

Note that the second embodiment exhibits the same effects as the first embodiment regardless of whether an omnidirectional or directional microphone is used.

Effects of the Invention As described above, the present invention provides a speaker for hands-free calls at the bottom of the handset and a directional microphone for hands-free calls on the side surface of the top of the handset, in addition to the speaker and microphone for handset calls. By weakening the acoustic coupling between the speaker and the microphone, it is possible to create a hands-free phone with good call quality and no disconnection at the beginning of the conversation. Furthermore, when a sound tube is used, a speaker can be easily mounted at the bottom of the handset.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a hands-free telephone according to a first embodiment of the present invention, FIG. 2 is a block diagram of a hands-free telephone according to a second embodiment of the present invention, and FIG. 3 is a diagram of a conventional hands-free telephone. FIG. 11...Handset (for handset calls), 1
2... Omnidirectional microphone (for handset calls), 13... (for hands-free calls)
Speaker, 14... (for hands-free calling)
Directional microphone, 21...Speaker (for hands-free calling), 22...- Sound tube, 23.
...Sound hole. Name of agent: Patent attorney Haruaki Ogata 2 people ζS 1 Figure <ty-> 11-Female speaking (b) 1:00-4: 1) Microphone e+1
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Claims (7)

[Claims] (1) Equipped with a speaker dedicated to hands-free calls installed at the bottom of the handset and a directional microphone dedicated to hands-free calls installed on the side of the top of the handset, standing upright with the receiver facing up and the transmitter facing down. installed in the condition,
A hands-free phone that allows both handset calls by lifting the phone and hands-free calls while the phone is installed. (2) The hands-free telephone set according to claim 1, wherein the directional microphone is a bidirectional microphone with its front axis facing forward. (3) The hands-free telephone set according to claim 1, wherein the directional microphone is a unidirectional microphone with its front axis facing upward. (4) A speaker dedicated to hands-free calls embedded inside the handset such as the grip part of the handset or the area around the transmitter, a sound hole provided at the bottom of the handset, and an acoustic tube that guides the sound from the speaker to the sound hole. It is equipped with a microphone for hands-free calls attached to the top of the handset, and is installed in an upright position with the receiver side up and the transmitter side down. A hands-free phone that allows both free calls. (5) The hands-free telephone set according to claim 4, wherein the hands-free microphone is a directional microphone attached to a side surface of the upper part of the handset. (6) The hands-free telephone set according to claim 5, wherein the directional microphone is a bidirectional microphone with its front axis facing forward. (7) The hands-free telephone set according to claim 5, wherein the directional microphone is a unidirectional microphone with the front axis facing upward.