JP4631070B2 - Bone conduction speaker - Google Patents

Description

Currently, sound output devices such as earphones that are used in portable audio equipment are small and simple in structure, but because they use a structure that uses air conduction sound, it is necessary to block the ear canal when worn. There was a problem that it was difficult to hear surrounding sounds.

On the other hand, an earphone device using a structure that transmits a bone conduction sound by contacting a bone conduction speaker near the ear canal of the ear and senses an output sound without blocking surrounding sounds is disclosed in Japanese Patent Laid-Open No. 2001-2001. Filed and published as 3202090.

In general, in the case of an earphone device using a bone-conducted sound that does not block the external auditory canal, it is easier to hear surrounding sounds during sound reproduction compared to an earphone device that closes and attaches the external ear canal There is.

As a bone conduction speaker used in such a bone conduction type earphone device, a bone conduction speaker that vibrates the entire casing or one side as disclosed in Japanese Patent Laid-Open No. 01-066707 and Japanese Translation of PCT International Publication No. 2004-507951 has been disclosed and registered. .

In Japanese Patent Laid-Open No. 01-066707, a bone conduction speaker with a built-in drive unit is built in a helmet or the like, and a vibration transmission unit provided on one side of the case is vibrated by pressing against the user's head using the drive unit. This makes it possible for the user to sense bone conduction sound without feeling the burden of wearing.

The bone conduction speaker disclosed in Japanese Patent Application Laid-Open No. 01-066707 can obtain the effect of amplification of the received voice level in the speaker by utilizing the resonance characteristics by suspending and fixing the drive unit to the vibration transmission unit. Due to the structure of transmitting the bone conduction sound by vibrating the entire drive unit supported by the spring body, the sound pressure drops sharply in a band other than the resonance frequency, and it is difficult to produce a reproduced sound with high reproducibility in a wide band. Had problems.

On the other hand, the special table 2004-507951 has been filed and disclosed as described above as a bone conduction speaker having a voice coil provided on the case side. The voice coil is provided on the case side, and the magnetic circuit is provided on the case inner wall by a suspension. It is possible to transmit a wide-band bone conduction sound to the user by properly using the vibration in the bone conduction speaker attached with the voice coil and the vibration by the magnetic circuit part.

By using this structure, the bone conduction speaker described in Japanese Translation of PCT International Publication No. 2004-507951 achieves a wide band of bone conduction sound transmitted and reproduced from the case.

Furthermore, the cushion member provided in the portion that comes into contact with the head portion has the structure of adjusting the frequency band of vibration to be transmitted and the soundproofing function of the device itself without increasing the number of parts.

JP2001-320790A Special Table 2004-507951 JP-A-01-067097

However, in the bone conduction speaker shown in the above-mentioned special table 2004-507951, since the pressure contact force is concentrated on the diaphragm that comes into contact with the head when used in pressure contact with the head, the bone conduction speaker in the low frequency band is used. There has been a problem that the frequency band and the like are limited during reproduction of the sound guide.

In addition, because of the structure using the second diaphragm attached to the case side during playback in the frequency band of the high frequency band, sound leakage to the outside due to the vibration of the case occurs, and in the high frequency band There is also a problem that the reproduction content leaks to the outside during the reproduction of the bone conduction sound.

In order to solve the above-mentioned problems, an object of the present invention is to provide a bone conduction speaker having a reproduction frequency over a wide band and having an effect of reducing sound leakage regardless of the reproduction frequency.

In order to solve the above-mentioned problem, in claim 1, a housing having a cylindrical inner wall is provided,
While disposing a conductive pad in the opening on one side of the housing,
A suspension provided on one side of the conductive pad, having an outer ring portion and an inner ring portion, the inner ring portion and the outer ring portion being connected by a plate-like arm portion, and a side of the suspension opposite to the side where the conductive pad is provided A drive unit comprising a voice coil provided on the surface of the housing is supported by fixing a suspension outer ring part to the inner wall of the housing,
A magnetic circuit part composed of a cup-shaped yoke provided with a magnet to which a pole piece is fixed is attached to the other housing opening by a cover so that the voice coil is disposed in a magnetic gap formed by the magnetic circuit part,
The structure is characterized in that a cushioning material made of an annular elastic body is provided at the outer edge of the housing on the side where the conductive pad is disposed, with a gap of at least 0.1 mm in the radial direction from the outer periphery of the conductive pad.

The bone conduction speaker according to claim 1, wherein the bone conduction speaker according to claim 1 has an annular planar shape between the outer peripheral edge portion of the conductive pad and the inner edge portion of the cushioning material, and is molded so that the cross section has a corrugated shape. It features a damper.

According to a third aspect of the present invention, in the bone conduction speaker according to the first and second aspects, a step portion corresponding to the outer diameter of the voice coil is provided at the center of the suspension.

According to a fourth aspect of the present invention, in the bone conduction speaker according to any one of the first to third aspects, the conductive pad has a protrusion on the suspension side and a protrusion on the magnetic circuit side of the suspension.

According to a fifth aspect of the present invention, in the bone conduction speaker according to the first to fourth aspects, with respect to the suspension, a lead wire of the voice coil is routed along an arm portion of the suspension and is electrically connected to a power supply terminal provided in the housing. It is characterized in that it is connected.

According to the first aspect of the present invention, the bone has a reproduction frequency band over a wide band and has the effect of reducing sound leakage in all reproduction frequency bands different from the bone conduction speaker described in Patent Document 2 described above. A conductive speaker can be obtained.

The bone conduction speaker of the present invention uses a dynamic speaker structure as a structure for reproducing and transmitting bone conduction sound, and a diaphragm used for a dynamic speaker for air conduction sound reproduction is configured by a suspension and a conduction pad. Bone conduction sound can be reproduced and transmitted.

In addition, by providing a cushioning material on the outer edge of the housing, it is possible to reduce the excessive deformation of the conductive pad and the suspension in a usage form in which the cushioning material is pressed against an ear such as an ear clip. In addition, since an appropriate pressure contact force is applied to the conductive pad, it is possible to obtain a wide reproduction frequency band and clear sound quality when reproducing the bone conduction sound.

Furthermore, by providing a gap of 0.1 mm or more between the cushioning material and the conductive pad, air conduction sound that leaks from the front side of the conductive pad is generated from the back side of the same conductive pad, and cancels out by air conduction sound that leaks from the inside of the housing Have gained. (See Figure 3)

Usually, since the bone conduction sound is directly transmitted to the human body through the conduction pad, the phase of the bone conduction sound is not disturbed by the phase of the sound wave radiated from the transmission pad to the space during reproduction.

In the present invention, based on the above points, focusing on the fact that the phase of the air conduction sound coming out from the front side and the back side of the conductive pad is shifted by 180 °, a structure that cancels out these two air conduction sounds is used. This makes it possible to reduce sound leakage.

In order to provide the above structure, the present invention uses a structure that transmits air conduction sound generated from the back side of the conductive pad through the gap between the conductive pad and the surrounding cushioning material to the outside of the housing from the gap between the conductive pad and the surrounding cushioning material. Yes.

By using the structure described above, the present invention cancels the air conduction sound outside the housing generated on the front side of the conductive pad, and as a result, it is possible to reduce the sound pressure of the air conduction sound leaking from the bone conduction speaker. .

According to the second aspect of the present invention, the dustproof damper molded in the corrugation shape is provided between the outer periphery of the conductive pad and the inner periphery of the cushioning material to prevent foreign matter from entering the case, and at the same time, the corrugation provided in the dustproof damper. Thus, it is possible to prevent the drive unit including the transmission pad, the suspension, and the voice coil from rolling.

According to the third aspect of the present invention, by providing a step portion matching the outer diameter of the voice coil at the center of the suspension, positioning when bonding the voice coil to the suspension during assembly is facilitated. .

According to the fourth aspect of the present invention, the conductive pad has a protrusion protruding to the magnetic circuit side, thereby preventing contact between the voice coil and the yoke when excessive pressure contact force is applied to the conductive pad. It becomes possible to prevent damage to the coil.

According to the fifth aspect of the present invention, in the bone conduction speaker according to any one of the first to fourth aspects, the lead wire of the voice coil is routed along the arm portion of the suspension and connected to the contact terminal of the bone conduction speaker. As a result, the internal structure can be simplified and the size can be easily reduced.

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a side sectional view of a bone conduction speaker used in the present embodiment and a perspective view of a component structure, respectively.

As shown in FIGS. 1 and 2, the bone conduction speaker of the present embodiment includes a magnetic field generated by a drive unit composed of a conductive pad 1, a suspension 3, and a voice coil 4, a pole piece 5, a magnet 6, and a yoke 7. It drives by the interaction of the magnetic field which the magnetic circuit part which consists of.

In the present embodiment, the drive unit and the magnetic circuit unit are provided in a case part including a cover 10 fitted to a housing 9, a dustproof damper 2 for supporting the conductive pad 1, and a buffer material 8.

The suspension 3 used in this embodiment is composed of an outer ring portion, an inner ring portion, and an arm portion that connects them. (See Figure 4)

Here, the suspension 3 is disposed in the housing molding die when the housing 9 is molded, and is then integrally molded with the housing 9 by insert molding in which resin is poured into the die, so that an assembling process is unnecessary. ing.

The bone conduction speaker of this embodiment has a structure in which the conduction pad 1 attached to the suspension 3 vibrates by a signal input to the voice coil 4 and the user senses bone conduction sound through the conduction pad 1.

Further, the lead wire 12 of the voice coil 4 is routed over the arm portion of the suspension 3 so that the size can be easily reduced.

Further, by providing an annular cushioning material 8 on the outer edge of the housing 9, when mounting on the ear clip or the like described in the prior art, an excessive applied pressure is received by the cushioning material.

For this reason, in the bone conduction speaker according to the present embodiment, when the bone conduction sound is transmitted from the conduction pad 1, vibration due to the voice coil 4 is difficult to be suppressed, and vibration with good followability with respect to the input signal can be obtained. Even at times, it is possible to obtain a wide reproduction sound with good clarity.

Further, as shown in FIG. 3, the air conduction sound generated by the conductive pad 1 is canceled by providing a gap between the cushioning material 8 and the conductive pad 1, thereby restricting the reproduction of the bone conductive sound. This makes it possible to greatly reduce sound leakage to the outside without having to do so.

Furthermore, since the bone conduction sound is reproduced only by the conductive pad 1 with respect to the fixed housing 9, the bone conduction sound in a wide frequency band can be provided to the user.

In this embodiment, a dustproof damper 2 is provided between the conductive pad 1 and the buffer material 8. For this reason, at the time of bone-conduction sound reproduction, it is possible to limit the rolling of the conductive pad 1 and prevent foreign matter from entering the housing with a single component.

Furthermore, by providing the conductive pad 1 with a convex part on the magnetic circuit part side, the excessive movement of the drive part is limited, and the voice coil 4, the suspension 3 and the like are in contact with the magnetic circuit part. It becomes possible to prevent damage.

As described above, according to the present embodiment, it is possible to provide a bone conduction speaker having a reproduction frequency over a wide frequency band and having an effect of reducing sound leakage regardless of the reproduction frequency.

Side sectional view of a bone conduction speaker used in this embodiment Component structure of bone conduction speaker used in the embodiment of the present invention Principle of canceling air conduction sound used in the embodiment of the present invention Structural diagram of suspension in the embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive pad 2 Dust-proof damper 3 Suspension 4 Voice coil 5 Pole piece 6 Magnet 7 Yoke 8 Buffer material 9 Housing 10 Cover 11 Terminal 12 Voice coil lead wire

Claims (5)

A housing having a cylindrical inner wall;
While disposing a conductive pad in the opening on one side of the housing,
A suspension provided on one side of the conductive pad, having an outer ring portion and an inner ring portion, the inner ring portion and the outer ring portion being connected by a plate-like arm portion, and a side of the suspension opposite to the side where the conductive pad is provided A drive unit comprising a voice coil provided on the surface of the housing is supported by fixing a suspension outer ring part to the inner wall of the housing,
A magnetic circuit part composed of a cup-shaped yoke provided with a magnet to which a pole piece is fixed is attached to the other housing opening by a cover so that the voice coil is disposed in a magnetic gap formed by the magnetic circuit part,
A bone conduction speaker characterized in that a cushioning material made of an annular elastic body is provided on the outer edge of the housing on the side where the conductive pad is disposed, with a clearance of at least 0.1 mm in the radial direction from the outer periphery of the conductive pad. The bone conduction speaker according to claim 1, wherein a dustproof damper having an annular planar shape and a cross-section having a corrugation shape is provided between the outer peripheral portion of the conductive pad and the inner peripheral portion of the cushioning material. . The bone conduction speaker according to claim 1 or 2, wherein a stepped portion corresponding to the outer diameter of the voice coil is provided at the suspension central portion. The bone conduction speaker according to claim 1, wherein the conductive pad has a protrusion on the suspension side, and a protrusion is formed on the magnetic circuit side of the suspension. The bone conduction speaker according to claim 1, wherein a lead wire of the voice coil is routed along an arm portion of the suspension and is electrically connected to a power supply terminal provided in the housing.