JP6563327B2 - earphone - Google Patents

Description

  The present invention relates to an earphone.

  There are various types of earphones, such as ear-hook type, headphone type, and separate type. One type of earphone is an earplug type.

  Earplug earphones (hereinafter referred to as “canal earphones”) guide sound waves to a driver unit that generates sound waves according to electrical signals, a housing that houses the driver units, and a space in front of the driver units. A sound conduit communicating with a space in the ear canal; and an earpiece attached to the sound conduit. A user of a canal-type earphone (hereinafter referred to as “user”) uses an earpiece inserted into the ear canal. Here, the front of the driver unit is the traveling direction of the sound wave from the driver unit.

  The earpiece inserted into the ear canal is in close contact with the inner wall of the user's ear canal. As a result, the space in the ear canal is sealed by the earpiece. Here, the space in the ear canal refers to a space formed by the inner wall of the user's ear canal, the eardrum, and the ear piece when the earpiece and the inner wall of the user's ear canal are in close contact. Sound waves from the driver unit reach the user's tympanic membrane through a sealed space in the ear canal. Therefore, the canal type earphone realizes reproduction with high sound quality. In addition, the sound insulation characteristics of the canal type earphone are superior to those of other types of earphones.

  When the canal-type earphone is worn on the user's ear (when worn), the canal-type earphone seals the space in the ear canal while pushing air in the ear canal toward the eardrum. Therefore, the pressure in the space inside the ear canal becomes higher than the pressure (atmospheric pressure) in the space outside the housing. As a result, a pressure difference occurs between the space inside and outside the user's eardrum, that is, the space in the ear canal and the space in the ear canal, and the mobility of the user's eardrum is reduced. The pressure difference in the space inside and outside the user's eardrum is adjusted by the ear canal and decreases with time. However, the pressure in the space in the ear canal and the pressure in the space in the ear canal are still higher than the pressure in the space outside the housing.

  As described above, when the canal-type earphone is worn, the pressure in the space in the ear canal and the pressure in the space in the ear canal are higher than the pressure in the space outside the housing. At this time, when the canal-type earphone is unloaded from the user's ear (when unloaded), the space in the ear canal communicates with the space outside the housing. For this reason, the pressure in the space in the ear canal is reduced to be equal to the atmospheric pressure. As a result, a pressure difference is generated in the space inside and outside the user's eardrum, and the mobility of the user's eardrum is reduced.

  When canal earphones are frequently attached and detached, adjustment of the pressure difference by the ear canal cannot keep up with the attachment and detachment. That is, the state where the mobility of the user's eardrum is reduced, that is, the state where it is difficult to hear sound continues.

  In the past, in order to suppress a decrease in the mobility of the user's eardrum, a vent pipe that communicates the space inside the ear canal and the space outside the housing, and an on-off valve that opens and closes the vent pipe Earphones have been proposed (see, for example, Patent Document 1).

  The open / close valve of the earphone described in Patent Document 1 is opened by the user's finger (hereinafter referred to as “operation of the open / close valve”) to open the vent pipe. The vent pipe communicates the space in the ear canal with the space outside the housing by the user's operation of the on-off valve. The user wears a canal-type earphone on the user's ear while operating the on-off valve. That is, the canal-type earphone is worn on the user's ear with the vent pipe open. As a result, no pressure difference occurs in the space inside and outside the user's eardrum. That is, the mobility of the user's eardrum does not decrease when the canal earphone is worn.

JP 2008-147710 A

  However, the earphone described in Patent Document 1 is provided with a protrusion on the outer peripheral surface of the housing. A groove is formed inside the protrusion. This groove constitutes a vent pipe that communicates the space in the ear canal and the space outside the housing. The vent tube communicates the space in the ear canal and the space outside the housing in a state where the vent tube is open. The state in which the vent pipe is opened is maintained only while the user operates the on-off valve. In other words, the user needs to operate the on-off valve in order to keep the vent pipe open. The user's operation of the on-off valve is required every time the canal-type earphone is worn on the user's ear.

  As described above, since the earphone described in Patent Document 1 needs to be provided with a protrusion for forming a groove on the outer peripheral surface of the housing, the structure of the earphone housing becomes complicated. Moreover, in the earphone described in Patent Document 1, the operation burden on the user for maintaining the open state of the vent pipe is large.

  The present invention has been made to solve the above-described problems of the prior art, and the mobility of the eardrum can be achieved by communicating the space inside the ear canal and the space outside the housing with a simple structure and operation. The purpose of this is to reduce the decrease in the user's operation and to reduce the operation burden on the user.

  An earphone according to the present invention includes a driver unit, a housing that houses the driver unit, and a first communication hole that communicates a space in front of the driver unit and a space in the rear of the driver unit among spaces inside the housing. The first communication hole is opened and closed by a diaphragm holding body that holds a diaphragm included in the driver unit.

  ADVANTAGE OF THE INVENTION According to this invention, suppression of the fall of the eardrum mobility and a user's operation burden can be reduced.

It is right side sectional drawing which shows embodiment of the earphone concerning this invention. FIG. 2 is a right side cross-sectional view of a driver unit included in the earphone of FIG. 1. FIG. 3 is a front view of the driver unit of FIG. 2. FIG. 4 is a right side cross-sectional view showing a state where a first communication hole provided in the earphone of FIG. 1 is closed. FIG. 2 is a right side cross-sectional view schematically showing the earphone of FIG. 1 attached to a user's ear. 3 is a flowchart showing the operation of the earphone of FIG. 1. It is a flowchart which shows the operation | movement of the earphone in another embodiment of the earphone concerning this invention.

  Hereinafter, embodiments of an earphone according to the present invention will be described with reference to the drawings.

● Earphone (1) ●
First, the configuration of the earphone according to the present invention will be described.

Configuration of Earphone (1) FIG. 1 is a right side cross-sectional view showing an embodiment of an earphone according to the present invention.
The model of the earphone 100 is an earplug type (canal type). The earphone 100 includes a housing 1, a driver unit 2, a sound conduit 3, and an earpiece 4.

  In the following description, in a state where the earphone 100 is attached to the user's ear, the side facing the user's eardrum (the left side of the paper) is referred to as the front. The opposite side (the right side of the drawing) is referred to as the rear.

  The housing 1 houses the driver unit 2. The housing 1 is made of synthetic resin or the like. The housing 1 is a hollow body. A second communication hole 2 h and an insertion hole 11 h through which the sound conduit 3 is inserted are formed on the outer wall of the housing 1.

  The second communication hole 2h communicates the space outside the housing 1 and the space inside the housing 1 and behind the driver unit 2.

FIG. 2 is a right side sectional view of the driver unit 2.
FIG. 3 is a front view of the driver unit 2 of FIG.
For example, the driver unit 2 generates a sound wave according to an electric signal from a sound reproducing device to which the earphone 100 is connected. The driver unit 2 includes a unit frame 21, a magnetic circuit 22, a diaphragm 23, a diaphragm holder (diaphragm ring) 24, an edge 25, a voice coil 26, and an urging portion 27. The driver unit 2 has a circular disc shape in plan view.

  The unit frame 21 houses a magnetic circuit 22, a diaphragm 23, a diaphragm ring 24, an edge 25, a voice coil 26, and an urging portion 27. The unit frame 21 is made of synthetic resin or the like. The unit frame 21 is cylindrical. Among the inner diameters of the unit frame 21, the inner diameter on the front end side of the unit frame 21 is larger than the inner diameters of other parts of the unit frame 21. A portion of the unit frame 21 having a small inner diameter is a circuit support portion 21 a that supports the magnetic circuit 22. Of the unit frame 21, a portion having a large inner diameter is a ring holding portion 21 b that holds the diaphragm ring 24.

  The unit frame 21 may be formed integrally with the housing 1 as a part of the housing 1, for example.

  The circuit support portion 21 a supports the magnetic circuit 22 in the unit frame 21. A groove 21 a 1 is formed in a part of the inner peripheral surface of the circuit support portion 21 a in the front-rear direction of the unit frame 21.

  The ring holding part 21 b holds the diaphragm ring 24 in the unit frame 21. A groove 21b1 is formed in a part of the inner peripheral surface of the ring holding portion 21b in the front-rear direction of the unit frame 21. The grooves 21b1 are formed at three locations at equal intervals along the circumferential direction of the ring holding portion 21b.

  The number and arrangement of the grooves 21b1 are not limited to the number in the present embodiment. That is, for example, the plurality of grooves 21b1 may be unevenly distributed in the circumferential direction of the ring holding portion 21b.

  The magnetic circuit 22 generates a magnetic flux in the magnetic circuit 22. The magnetic circuit 22 includes a yoke 22a, a magnet 22b, and a pole piece 22c. The yoke 22a is made of a magnetic material. The yoke 22a has a bottomed cylindrical shape. The yoke 22a is fitted to the circuit support portion 21a of the unit frame 21 with the opening end directed toward the ring holding portion 21b. The magnet 22b is a permanent magnet. The magnet 22b is cylindrical. The magnet 22b is disposed at the center of the bottom of the yoke 22a. The pole piece 22c is made of a magnetic material. The pole piece 22c has a circular disc shape in plan view. The pole piece 22c is disposed so as to overlap the magnet 22b in the front-rear direction. That is, the magnet 22b is disposed between the yoke 22a and the pole piece 22c. A gap is formed between the inner peripheral surface of the yoke 22a and the outer peripheral surface of the pole piece 22c.

  The magnet 22b has N poles on the pole piece 22c side and S poles on the yoke 22a side. That is, the magnetic flux generated in the magnetic circuit 22 is directed in a direction crossing the gap between the yoke 22a and the pole piece 22c from the pole piece 22c to the yoke 22a. That is, in the magnetic circuit 22, a magnetic gap that is a gap that the magnetic flux crosses is formed.

  The groove 21a1 of the circuit support portion 21a faces the outer peripheral surface of the yoke 22a. A first communication hole 1h is formed by the groove 21a1 of the circuit support portion 21a and the outer peripheral surface of the yoke 22a. That is, the first communication hole 1 h is formed in the driver unit 2. The front end surface of the circuit support portion 21a and the front end surface of the yoke 22a are arranged on the same plane.

  The diaphragm 23 vibrates according to the electrical signal. As a result, a sound wave corresponding to the electrical signal is generated. The diaphragm 23 is made of synthetic resin or the like. The diaphragm 23 is a circular plate in plan view. The diaphragm 23 vibrates regardless of whether the first communication hole 1 h is opened or closed by the diaphragm ring 24. That is, a sound wave corresponding to the electrical signal is generated regardless of whether the first communication hole 1h is opened or closed. The diaphragm ring 24 will be described later.

  The diaphragm ring 24 holds the diaphragm 23. The diaphragm ring 24 is made of synthetic resin or the like. The diaphragm ring 24 has a ring shape. The diaphragm ring 24 is held inside the ring holding part 21b. The diaphragm ring 24 is movable in the front-rear direction. The rear surface of the diaphragm ring 24 faces the front end surface of the circuit support portion 21a and the front end surface of the yoke 22a. The outer peripheral surface of the diaphragm ring 24 is in contact with the inner peripheral surface of the ring holding portion 21b. The groove 21 b 1 of the ring holding part 21 b faces the outer peripheral surface of the diaphragm ring 24. A gap G1 is formed between the groove 21b1 of the ring holding portion 21b and the outer peripheral surface of the diaphragm ring 24.

  The diaphragm ring 24 opens and closes the first communication hole 1 h based on a DC bias current (hereinafter referred to as “DC current”) supplied to the voice coil 26. That is, the diaphragm ring 24 functions as an on-off valve that opens and closes the first communication hole 1h. The operation of the diaphragm ring 24 will be described later.

  The edge 25 connects the diaphragm 23 and the diaphragm ring 24. The edge 25 is made of an elastic body or the like. The edge 25 is a ring-shaped film.

  The voice coil 26 moves in the front-rear direction according to the electromagnetic force generated from the current supplied to the voice coil 26 and the magnetic flux generated by the magnetic circuit 22. The voice coil 26 is a coil in which one conductive wire is wound spirally. The voice coil 26 has a ring shape. The voice coil 26 is inserted through a magnetic gap formed in the magnetic circuit 22. One end (front end) of the voice coil 26 is joined to the rear surface of the diaphragm 23. Therefore, when the voice coil 26 moves, the diaphragm 23 also moves. That is, the diaphragm 23 and the voice coil 26 move together. The other end (rear end) of the voice coil 26 is joined to an urging portion 27 described later.

  The urging unit 27 urges the diaphragm 23 forward, that is, in a direction in which the first communication hole 1h is opened. The urging unit 27 is, for example, a leaf spring. The urging portion 27 is accommodated in the yoke 22a. That is, the urging unit 27 is accommodated in the magnetic circuit 22. The front end of the urging portion 27 is joined to the rear end of the voice coil 26. The rear end of the urging portion 27 is joined to the inner surface of the yoke 22a.

  The diaphragm 23 is urged forward by the urging force of the urging portion 27 via the voice coil 26. When the diaphragm 23 is biased, the diaphragm ring 24 is also biased forward. At this time, a gap G2 is formed between the rear surface of the diaphragm ring 24, the front end surface of the circuit support portion 21a, and the front end surface of the yoke 22a.

Returning to FIG.
The unit frame 21 of the driver unit 2 is housed in the housing 1. The space inside the housing 1 is divided into a space in front of the driver unit 2 (hereinafter referred to as “space S1”) and a space behind the driver unit 2 (hereinafter referred to as “space S2”) by the driver unit 2 housed in the housing 1. It is divided into.

  Here, the space outside the housing 1 and the space S2 communicate with each other through the second communication hole 2h. The space S1 and the space S2 communicate with each other through the gap G1, the gap G2, and the first communication hole 1h. That is, the space S1 communicates with the space outside the housing 1 through the gap G1, the gap G2, the first communication hole 1h, and the space S2.

  When the diaphragm ring 24 is in contact with the opening end on the front side of the first communication hole 1h and the first communication hole 1h is closed, the space S1 and the space outside the housing 1 do not communicate with each other. On the other hand, when the diaphragm ring 24 is separated from the opening end on the front side of the first communication hole 1h and the first communication hole 1h is opened, the space S1 and the space outside the housing 1 communicate with each other.

  A direct current is supplied to the voice coil 26 from the outside of the earphone 100. At this time, the diaphragm ring 24 moves backward based on the electromagnetic force generated in the voice coil 26. As a result, the diaphragm ring 24 contacts the opening end on the front side of the first communication hole 1h, and the first communication hole 1h is closed. That is, the space S1 and the space outside the housing 1 do not communicate with each other while a direct current is supplied to the voice coil 26 from the outside.

FIG. 4 is a right side cross-sectional view showing a state in which the first communication hole 1h is closed.
The figure shows that the diaphragm ring 24 closes the first communication hole 1h and that the space S1 and the space outside the housing 1 are not in communication.

Returning to FIG.
When the supply of the direct current to the voice coil 26 is stopped, the above-described electromagnetic force disappears, and the diaphragm ring 24 moves forward by the urging force of the urging portion 27. As a result, the diaphragm ring 24 is separated from the opening end on the front side of the first communication hole 1h, and the first communication hole 1h is opened. That is, when the supply of direct current to the voice coil 26 is stopped, the space S1 and the space outside the housing 1 communicate with each other.

  The sound conduit 3 guides the sound wave from the driver unit 2 to the ear canal of the user of the earphone 100 (hereinafter referred to as “user”). The sound conduit 3 is made of synthetic resin or the like. The sound conduit 3 is cylindrical. The sound conduit 3 projects from the housing 1. The rear end side of the projecting sound conduit 3 is inserted into the insertion hole 11 h of the housing 1. The space inside the sound conduit 3 communicates with the space S1.

  The earpiece 4 has an umbrella shape made of an elastic body. The earpiece 4 is attached to the front end of the sound conduit 3. The earpiece 4 is inserted into the user's ear canal along with the sound conduit 3. The earpiece 4 inserted into the user's ear canal is in close contact with the inner wall of the user's ear canal.

Operation of Earphone (1) Next, the operation of the earphone 100 will be described.

FIG. 5 is a right side cross-sectional view schematically showing the earphone 100 attached to the user's ear.
FIG. 6 is a flowchart showing the operation of the earphone 100.

  When the earphone 100 is not used, that is, when it is not worn on the user's ear, the first communication hole 1 h is in an open state, that is, a state in which no direct current is supplied to the voice coil 26. Hereinafter, the case where the earphone 100 with the first communication hole 1h opened is attached to the user's ear will be described as an example.

  When the earphone 100 is attached to the user's ear, the earpiece 4 is in close contact with the inner wall EC of the user's ear canal.

  At this time, the space inside the ear canal (hereinafter referred to as “space S3”) and the other spaces (hereinafter referred to as “space S4”) excluding the space S3 among the spaces outside the housing 1 communicate with each other. That is, the space S3 communicates with the space S4 through the space inside the sound conduit 3, the space S1, the gap G1, the gap G2, the second communication hole 2h, the space S2, and the second communication hole 2h. Here, the space S3 in the ear canal is a space defined by the inner wall EC of the ear canal, the eardrum E of the user, and the earpiece 4, and communicates with the space S1 through the sound conduit 3.

  As described above, since the earphone 100 is attached to the user's ear with the first communication hole 1h opened, the space S3 is not sealed. That is, the pressure in the space S3 is the same as the pressure in the space S4 (atmospheric pressure).

  The direct current is supplied to the voice coil 26, for example, when the sound player is turned on (Yes in S11). The direction of the direct current supplied to the voice coil 26 is away from the front side of the paper surface in the voice coil 26 on the first communication hole 1h side (upper side of the paper surface).

  At this time, due to Fleming's left-hand rule, an electromagnetic force directed backward is generated in the voice coil 26. Therefore, the voice coil 26 moves backward against the urging force of the urging unit 27. The diaphragm 23 and the diaphragm ring 24 move with the movement of the voice coil 26 until the diaphragm ring 24 contacts the opening end on the front side of the first communication hole 1h. That is, when a direct current is supplied to the voice coil 26, the diaphragm ring 24 closes the first communication hole 1h (S12). As a result, the space S1 does not communicate with the space S4. At this time, the space S3 is sealed. The state where the first communication hole 1h is closed is maintained until the supply of the direct current to the voice coil 26 is stopped.

  In a state where the first communication hole 1h is closed, for example, when an audio signal from an audio player is input to the voice coil 26, a current corresponding to the audio signal that is an AC current is converted to a DC current in the voice coil 26. Supplied in superposition. The direction of the alternating current supplied to the voice coil 26 is the same direction as the direction of the direct current supplied to the voice coil 26 or the opposite direction.

  At this time, according to Fleming's left-hand rule, an electromagnetic force is generated forward or backward in the voice coil 26. The voice coil 26 moves the diaphragm 23 back and forth, that is, vibrates. As the diaphragm 23 vibrates, a sound wave corresponding to the audio signal is generated. This sound wave reaches the user's tympanic membrane E with the space S3 sealed. Here, even if the voice coil 26 (diaphragm 23) vibrates, the diaphragm ring 24 does not leave the opening end of the front end of the first communication hole 1h.

  When the supply of the direct current to the voice coil 26 is stopped in the state where the first communication hole 1h is closed (No in S11), the electromagnetic force that moves the voice coil 26 backward disappears. Therefore, the voice coil 26 moves forward by the urging force of the urging unit 27. The diaphragm ring 24 moves away from the opening end in front of the first communication hole 1h as the voice coil 26 moves. As a result, the first communication hole 1h is opened. That is, when the supply of direct current to the voice coil 26 is stopped, the diaphragm ring 24 opens the first communication hole 1h (S13). As a result, the space S1 communicates with the space S4. The state in which the first communication hole 1h is opened is maintained until a direct current is supplied to the voice coil 26.

  In the state where the first communication hole 1h is opened, the sound wave from the space S4 reaches the user's eardrum E through the space S2, the space S1, and the space S3. As a result, the user can hear a sound (for example, a conversation sound) outside the housing 1 in a state where the earphone 100 is attached to the user's ear. That is, the user does not have to remove the earphone 100 from the ear in order to hear the sound outside the housing 1.

Summary According to the embodiment described above, the first communication hole 1h is provided by applying the electromagnetic force generated by supplying a direct current to the voice coil 26 and the urging force of the urging portion 27. Can be opened and closed. When the first communication hole 1h is opened, the space S3 communicates with the space S4. On the other hand, when the first communication hole 1h is closed, the space S3 does not communicate with the space S4. The state in which the first communication hole 1h is opened is maintained by the urging force of the urging portion 27. On the other hand, the state where the first communication hole 1h is closed is maintained by the electromagnetic force generated by the direct current supplied to the voice coil 26. Thus, according to the earphone 100, it is possible to suppress a decrease in the motility of the eardrum and to reduce the operation burden on the user.

● Earphone (2) ●
Next, another embodiment of the earphone according to the present invention will be described with a focus on differences from the above-described embodiment. The earphone in the present embodiment is different from the earphone in the above-described embodiment in that the first communication hole 1h is opened and closed in response to detection of an alternating current supplied to the voice coil 26.

FIG. 7 is a flowchart showing the operation of the earphone in another embodiment of the earphone according to the present invention.

  The earphone in the present embodiment includes detection means and a switch. The detection means detects an alternating current supplied to the voice coil 26. The switch controls the supply of direct current to the voice coil 26 according to the detection state of the alternating current by the detection means. In other words, when the alternating current is detected, the switch controls the earphone so that the direct current is supplied to the voice coil 26. In addition, when the alternating current is not detected, the switch controls the earphone so that no direct current is supplied to the voice coil 26. The direct current is supplied from an audio player, for example.

● Operation of Earphone (2) The earphone in the present embodiment is in a state where the first communication hole 1h is opened when not in use, like the earphone in the embodiment described above. Hereinafter, the case where the earphone with the first communication hole 1h opened is attached to the user's ear will be described as an example.

  In the state where the first communication hole 1h is opened, for example, when an audio signal from an audio player is input to the voice coil 26, an alternating current is supplied to the voice coil 26. At this time, a detection means detects an alternating current (Yes of S21). The switch controls the earphone to a state in which a direct current is supplied to the voice coil 26 when the detecting means detects the alternating current. That is, when an alternating current is supplied to the voice coil 26, a direct current is supplied to the voice coil 26 (S22). When a direct current is supplied to the voice coil 26, the diaphragm ring 24 closes the first communication hole 1h (S23). The state where the first communication hole 1h is closed is maintained while the detection means detects the alternating current.

  In the state where the first communication hole 1h is closed, for example, when the sound reproducing device stops outputting the sound signal, the supply of the alternating current to the voice coil 26 is stopped. If the detecting means does not detect an alternating current (No in S21), the switch controls the earphone so that no direct current is supplied to the voice coil 26 (S24). When the supply of direct current to the voice coil 26 is stopped, the diaphragm ring 24 opens the first communication hole 1h (S25). The state where the first communication hole 1h is opened is maintained while the detection means does not detect the alternating current.

Summary According to the embodiment described above, the first communication hole 1h can be opened and closed by controlling the supply of the direct current to the voice coil 26 in accordance with the alternating current supplied to the voice coil 26. . Therefore, even if there is no operation for supplying a direct current to the voice coil 26, the diaphragm ring 24 opens and closes the first communication hole 1h. The open / closed state of the first communication hole 1h is maintained according to the supply state of the alternating current.

DESCRIPTION OF SYMBOLS 1 Housing 1h 1st communication hole 11h Insertion hole 2 Driver unit 2h 2nd communication hole 21 Unit frame 21a Circuit support part 21b Ring holding | maintenance part 21a1 Groove 21b1 Groove 22 Magnetic circuit 22a Yoke 22b Magnet 22c Pole piece 23 Diaphragm 24 Diaphragm ring (Diaphragm holder)
25 Edge 26 Voice coil 27 Energizing portion 3 Sound conduit 4 Earpiece 100 Earphone E Ear drum EC Inner wall G1 Gap G2 Gap S1 Space in front of the driver unit S2 Space in the rear of the driver unit S3 Space in the outer ear canal S4 Outside the housing space

Claims (10)

A driver unit;
A housing for housing the driver unit;
A first communication hole for communicating a space in front of the driver unit and a space in the rear of the driver unit among the internal space of the housing;
Have
The first communication hole is opened and closed by a diaphragm holding body that holds a diaphragm included in the driver unit.
Earphone characterized by that. The driver unit is
A voice coil joined to the rear surface of the diaphragm;
A magnetic circuit having a magnetic gap in which the voice coil is disposed;
With
The diaphragm holder moves based on a direct current supplied to the voice coil.
The earphone according to claim 1. An urging portion for urging the diaphragm holder;
Comprising
The earphone according to claim 2 . The urging portion is housed inside the magnetic circuit,
One end of the urging portion is joined to the voice coil.
The earphone according to claim 3. The first communication hole is formed in the driver unit.
The earphone according to claim 1. A second communication hole for communicating a space outside the housing and a space behind the driver unit;
With
A space in front of the driver unit communicates with a space outside the housing through the first communication hole and the second communication hole.
The earphone according to claim 1. The urging portion urges the diaphragm holding body in a direction to open the first communication hole,
The diaphragm holder closes the first communication hole when a direct current is supplied to the voice coil.
According to claim 3 Symbol placement of the earphone. Connected to an audio player,
The voice coil is supplied with the direct current and the current corresponding to the audio signal from the audio player superimposed on each other,
7 Symbol placement of the earphone claim. A switch for controlling the supply of a direct current supplied to the voice coil;
The earphone according to claim 8. The switch supplies the DC current to the voice coil when a current corresponding to the audio signal is supplied to the voice coil.
The earphone according to claim 9.

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