JP2015002450A - Headphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a headphone comprising a noise cancel function for preventing influence of external sound and a function for preventing leakage of reproduction sound.SOLUTION: A headphone comprises: a first driver unit 4 in which a first air chamber 21 is formed by a ring-shaped ear pad 2 surrounding an ear of a user and being in contact with a temporal region of the user and which emits reproduction sound into the first air chamber; a microphone 31 for detecting external sound which penetrates into the first air chamber via a gap between the ear pad 2 and the temporal region of the user, and reproduction sound from the first driver unit 4 leaked from the first air chamber via the gap; and a second driver unit 32 which emits cancel sound into a second air chamber 25 while utilizing a cancel signal based on a detection signal from the microphone. The microphone 31 is arranged while communicating with the second air chamber 25 via a sound guide hole 1a and an opening 2b.

Description

  The present invention provides a noise canceling function for reducing foreign sounds entering through a gap between a user's temporal region and an ear pad, and a so-called sound in which a musical sound reproduced by a driver unit leaks to the outside through the gap. The present invention relates to headphones having a function of preventing leakage.

It is desirable that the ear-cover type headphones that are worn around the user's outer ear so that the external sound does not reach the user's ear as much as possible. In addition, when the user listens to the playback sound (musical sound) with the headphones, it may cause discomfort due to sound leakage to surrounding people other than the user, so the playback sound from the driver unit leaks to the outside. It is desirable not to.
Ear-cover headphones surround the user's ears with ear pads, and the ear pads are closely attached to the user's temporal region, thereby blocking the entry of external sounds and preventing the playback sound from leaking outside. Considered.

  FIG. 2 is a cross-sectional view showing a basic configuration of a conventional headphone having a noise canceling function in a state where the headphone is worn on a user's temporal region. This headphone includes a baffle plate 1 as a support substrate, and a ring-shaped ear pad 2 that covers a user's outer ear is attached to the periphery of one surface of the baffle plate 1. That is, a front air chamber FC is formed between the baffle plate 1, the ear pad 2, and the user's temporal region.

An opening 3 is formed in the central portion of the baffle plate 1, and a driver unit 4 is fitted and attached to the opening 3 so that reproduced sound from the driver unit 4 is emitted toward the user's external auditory canal. Works.
A housing 5 is attached to the baffle plate 1 so as to cover the back surface of the driver unit 4, and a rear air chamber BC is formed on the back surface side of the driver unit 4 by the housing 5.

  The driver unit 4 includes a bottomed cylindrical yoke 4a, and a magnet 4b and a pole piece 4c disposed in the yoke 4a to form a magnetic circuit, and an outer peripheral surface of the yoke 4a constituting the magnetic circuit. A flange member 4d formed in an annular shape is attached to the. The magnetic circuit is supported at the center of the baffle plate 1 by the flange member 4d, and a diaphragm 4e is attached to the front side of the flange member 4d.

A voice coil 4f attached to a boundary portion between the center dome and the sub dome of the diaphragm 4e is disposed in a magnetic gap formed between the yoke 4a and the pole piece 4c.
In the headphone shown in FIG. 2, a port 7 having a pipe member is formed in a part of the housing 5 in order to improve a low-frequency response.

The headphones having the above-described configuration are conventionally provided with a noise canceling function for reducing external sounds that enter through a gap between the temporal region and the earpad.
That is, in the configuration of the headphones shown in FIG. 2, the microphone 11 is attached to the baffle plate 1 so as to be located in the front air chamber FC described above. The detection signal from the microphone 11 is amplified by the preamplifier 12 and supplied to the inverting input terminal of the operational amplifier 13.
The non-inverting input terminal of the operational amplifier 13 is supplied with a tone signal to be reproduced by headphones from the input terminal IN. The output of the operational amplifier 13 is amplified by the power amplifier 14 and supplied to the driver unit 4.

According to the headphones having the noise canceling function shown in FIG. 2, a noise canceling signal having a phase opposite to that of the external sound (noise) entering through the gap between the user's temporal region and the earpad is generated by the operational amplifier 13. The signal is combined (added) to the signal, which is amplified by the power amplifier 14 and operates to drive the driver unit 4.
Therefore, in the front air chamber FC, it is possible to listen to the reproduced sound with a small amount of the external sound (noise) described above.

  The headphones having the noise canceling function as described above have been studied for a long time, and this is disclosed in Non-Patent Document 1, Patent Document 1, and the like.

Corona Co., Ltd. “Active Noise Control” Editor: The Japan Society of Acoustics, Published July 7, 2006 P133-134

JP-A-6-343195

  By the way, according to the headphones disclosed in the non-patent document 1 and the patent document 1, the signal for canceling the external sound (noise) and the musical sound signal are electrically combined (added). There arises a problem of sound quality deterioration that the musical sound signal is affected by the noise canceling signal. In addition, there is a problem that a difference in sound quality occurs between when the noise cancellation function is operated and when the noise cancellation function is not operated, and the user feels uncomfortable.

  On the other hand, in the headphones disclosed in Non-Patent Document 1 and Patent Document 1 described above, no consideration is given to measures against sound leakage that leaks outside through a gap between the user's temporal region and the earpad. The advent of headphones having both a countermeasure against this sound leakage and the above-described noise canceling function is desired.

  The present invention has been made paying attention to the above-described points, and is reproduced by a driver unit and a noise canceling function for reducing foreign sounds (noise) entering through a gap between a user's temporal region and an earpad, and a driver unit. It is an object of the present invention to provide a headphone having a function of preventing so-called sound leakage in which a musical sound leaks outside through the gap.

  A headphone according to the present invention made to solve the above-described problems forms a first air chamber by a ring-shaped ear pad that surrounds a user's ear and contacts the user's temporal region, and the first air chamber Leaks from the first air chamber through the first driver unit that radiates the reproduced sound, the extraneous sound that enters the first air chamber through the gap between the earpad and the user's temporal region, and the gap. A microphone for detecting a reproduction sound from the first driver unit; and a second driver unit for radiating a cancellation sound into the second air chamber using a cancellation signal based on a detection signal from the microphone. The structure arrange | positioned in the state connected to the said 2nd air chamber is employ | adopted.

  In this case, in a preferred embodiment, an opening is formed in a surface of the earpad that contacts the user's temporal region, the microphone is disposed in the earpad, and the microphone is formed in the earpad. Configured to detect the external sound and the reproduced sound in the unit.

  The first driver unit is attached to a baffle plate together with the ear pad, a first air chamber is formed on the front side of the baffle plate, and the second driver unit is a partition wall attached to the back surface of the baffle plate. And the structure accommodated in the 2nd air chamber between the housing which covers the further back surface of the said partition can be employ | adopted suitably.

  In this case, it is desirable that the microphone disposed in the ear pad be disposed in communication with the second air chamber via a sound guide hole formed in the baffle plate.

According to the headphones of the present invention, each of the external sound that enters the first air chamber through the gap between the ear pad and the user's temporal region and the reproduction sound (leakage sound) that leaks to the outside through the gap. A microphone for detection is provided.
Then, a cancel signal generated based on the external sound and leakage sound captured by the microphone is reproduced as a cancel sound by the second driver unit, and this acts on the microphone.

That is, at the position where the microphone is arranged, when the sound pressure due to the external sound increases, the sound pressure of the external sound is canceled by the sound pressure from the second driver unit (the sound pressure is lowered). Further, when the sound pressure of the leaked sound at the position where the microphone is arranged increases, the sound pressure of the leaked sound is also canceled by the sound pressure from the second driver unit (the sound pressure is lowered).
Therefore, both the extraneous sound and the leaking sound that pass through the gap between the earpad and the user's temporal region are canceled, and the extraneous sound and the leaking sound are substantially the same as those blocked at the earpad part. Will receive.

It is sectional drawing shown in the state with which the headphone which concerns on this invention was mounted | worn on the user's temporal region. It is sectional drawing shown in the state which mounted | wore the user's temporal region with the conventional noise cancellation type | mold headphones.

  A headphone according to the present invention will be described below with reference to FIG. In FIG. 1, parts that perform the same functions as those shown in FIG. 2 already described are denoted by the same reference numerals, and therefore detailed description thereof will be omitted as appropriate.

  In the headphones according to the present invention, a ring-shaped ear pad 2 that surrounds the user's ear and contacts the user's temporal region is attached along the periphery of the front side of the baffle plate 1. A first driver unit 4 is attached to the baffle plate 1 by using an opening 3 formed in the central portion of the baffle plate 1, whereby a first air chamber is formed on the front side of the baffle plate 1. 21 is formed.

The first driver unit 4 has the same configuration as the driver unit 4 shown in FIG. 2 described above, and a detailed description thereof will be omitted. Only a tone signal to be reproduced by the headphones is supplied to the first driver unit 4 from a power amplifier (not shown).
Therefore, the sound reproduced by the first driver unit 4 is radiated into the first air chamber 21, and the user can listen to it.

  The ear pad 2 is formed in a ring shape by packing an elastic material such as urethane or a fibrous body inside the covering, and the microphone 31 is disposed in a part of the elastic material. . And the opening 2a is formed in the said covering body in the surface which touches a user's temporal region in the ear pad 2, The said microphone 31 acts so that the sound wave of the opening 2a part may be detected.

That is, although the ear pad 2 is crimped to the user's temporal region when the headphones are worn, the user's hair or the like enters between the temporal region and the ear pad 2, so that there is a slight gap here. Often formed.
Therefore, the microphone 31 detects an external sound (noise) that enters the first air chamber through the gap, and also reproduces sound from the first driver unit 4 that leaks from the first air chamber through the gap. Can be detected.

On the other hand, on the back surface of the baffle plate 1, a partition wall 22 having a curved peripheral edge is attached to the baffle plate 1 so as to cover the back surface of the first driver unit 4. A rear air chamber 23 of the first driver unit 4 is formed between the partition wall 22 and the baffle plate 1.
Further, a housing 5 that covers the partition wall 22 is attached to the outer peripheral edge of the back surface of the baffle plate 1, and a second baffle plate 24 is formed integrally with the housing 5 in the housing 5. A second driver unit 32 is attached to the two baffle plate 24. The second driver unit 32 has the same configuration as the driver unit 4 shown in FIG. 2 described above, and a detailed description thereof is omitted.

A region surrounded by the second baffle plate 24, the second driver unit 32, and the partition wall 22 constitutes a second air chamber 25, and the second air chamber 25 is a front portion of the second driver unit 32. It constitutes an air chamber.
A rear air chamber 26 of the second driver unit 32 is configured between the second baffle plate 24 to which the second driver unit 32 is attached and the back surface of the housing 5.

In addition, the sound pad 1a is intermittently drilled in the circumferential direction at the mounting position of the ear pad 2 on the baffle plate 1 and the ear pad 2 is covered with the sound pad 1a. Is provided with an opening 2b.
With this configuration, the microphone 31 disposed in the ear pad 2 is in communication with the second air chamber 25 via the opening 2b and the sound guide hole 1a.

  Thus, the signal due to the external sound in the opening 2a detected by the microphone 31 and the signal due to the reproduction sound from the first driver unit 4 are amplified by the power amplifier 33 and phase-inverted to be a cancel signal. , And supplied to the second driver unit 32. Then, the sound reproduced by the second driver unit 32 is radiated as a cancel sound into the second air chamber 25.

  As described above, the microphone 31 is disposed in the ear pad 2 via the sound guide hole 1 a and the opening 2 b communicating with the second air chamber 25, and the microphone 31 is canceled by the second driver unit 32. Sound will act.

Therefore, when the sound pressure due to the external sound (noise) rises at the position where the microphone 31 is arranged, that is, the position where the ear pad 2 is pressed against the user's temporal region, the sound pressure due to the external sound is changed to the second driver. It acts to cancel (lower the sound pressure) by the sound pressure from the unit 32.
Further, when the sound pressure from the first driver unit 4 (the sound pressure of the leaked sound) increases at the crimping position, the sound pressure of the leaked sound is canceled by the sound pressure from the second driver unit. It works to do (decrease the sound pressure).

Due to the above-described action, both the external sound and the leakage sound that pass through the gap between the ear pad 2 and the user's temporal region are canceled, and the foreign sound and the leakage sound are substantially blocked at the portion of the ear pad 2. Will receive the same effect.
As a result, the noise canceling function for reducing the external sound entering through the gap between the user's temporal region and the ear pad 2 and the musical sound reproduced by the first driver unit 4 leak to the outside through the gap. Thus, it is possible to provide a headphone having a function of preventing so-called sound leakage.

  In the power amplifier 33 described above, the signal detected by the microphone 31 is amplified and phase-inverted to generate a cancel signal, but this does not require any special phase-inversion processing, and power This can be realized by reversely connecting the positive and negative input terminals of the voice coil of the second driver unit 32 to the positive and negative output terminals of the amplifier 33.

The power amplifier 33 preferably includes level adjusting means for adjusting the level of the cancel signal applied to the second driver unit 32, and the level adjusting means adjusts the level of the canceling sound applied to the microphone 31. can do.
Thereby, it is possible to set the noise canceling function for reducing the external sound and the sound leakage preventing function to the optimum operation state.

According to the headphones according to the present invention described above, it is possible to provide headphones having both a noise canceling function for reducing the influence of external sound and a function for preventing sound leakage of reproduced sound.
In addition, since the first driver unit 4 can reproduce only a musical sound signal that does not include a cancel signal or the like, there is a problem of sound quality degradation that the headphones disclosed in the above-mentioned patent documents have. It is also possible to expect unique operational effects other than the matters described in the column of the effect of the invention described above.

DESCRIPTION OF SYMBOLS 1 Baffle board 1a Sound guide hole 2 Ear pad 2a, 2b Opening 4 1st driver unit 5 Housing 21 1st air chamber 22 Bulkhead 25 2nd air chamber 31 Microphone 32 2nd driver unit 33 Power amplifier

Claims (4)

A first driver unit that surrounds the user's ear, forms a first air chamber with a ring-shaped earpad that contacts the user's temporal region, and radiates reproduced sound into the first air chamber;
Microphone that detects external sound that enters the first air chamber through a gap between the earpad and the user's temporal region and reproduced sound from the first driver unit that leaks from the first air chamber through the gap. When,
A second driver unit that emits a cancellation sound into the second air chamber using a cancellation signal based on a detection signal from the microphone;
The headphone according to claim 1, wherein the microphone is disposed in communication with the second air chamber.   An opening is formed in a surface of the earpad that contacts the user's temporal region, the microphone is disposed in the earpad, and the microphone is configured to be used for the external sound and the reproduction in the opening formed in the earpad. The headphone according to claim 1, wherein sound is detected.   The first driver unit is attached to the baffle plate together with the ear pad, a first air chamber is formed on the front side of the baffle plate, and the second driver unit is a partition wall attached to the back surface of the baffle plate; The headphone according to claim 1 or 2, wherein the headphone is housed in a second air chamber between the partition wall and a housing that covers a back surface of the partition wall.   The microphone disposed in the ear pad is disposed in a state where the microphone communicates with the second air chamber through a sound guide hole formed in the baffle plate. headphone.

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