JP2009111820A - Bone conduction earphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further miniaturize a vibration source, as compared with the prior art, to consequently miniaturize a bone conduction earphone itself by disposing a substrate and a piezoelectric diaphragm so as to be overlapped, while being spaced apart from each other. <P>SOLUTION: A vibration source 31 housed within a housing chamber 15 of an earphone body 11 includes a rectangular substrate 32 and a piezoelectric diaphragm 41 which is partially fixed on the substrate 32, while being spaced apart from the substrate 32. The vibration of the piezoelectric diaphragm 41 is also transmitted to the substrate 32 via a spacer 36, makes the vibration source 31 vibrate as a whole and makes the earphone body 11 vibrate. The vibration of the earphone body 11 is transmitted to the external ear of a user via an ear insert portion 21, converted into an electrical signal via the external ear, via the cochlear organ and the auditory nerve and is transmitted to the brain. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bone conduction earphone in which vibration due to a piezoelectric body is transmitted to a cochlear organ, for example, via an outer ear.

Generally used earphones transmit sound generated from an electromagnetic speaker to a human eardrum by air vibration. On the other hand, a bone conduction type speaker is also known that presses a vibration surface against a hard part of the skeleton of the head with a constant pressure to transmit sound due to vibration.
Since this bone conduction type speaker uses a piezoelectric diaphragm as a vibration generation source, a drive signal supplied to the piezoelectric diaphragm requires a larger voltage than an electromagnetic type speaker. For this reason, an amplifier circuit for amplifying an externally input signal is required on the input side of the piezoelectric diaphragm.

  Patent Document 1 discloses a technique in which an electronic circuit formed on a substrate and a piezoelectric vibrating body are integrally molded with a resin.

JP 2006-5625 A

However, in the technique described in Patent Document 1, a piezoelectric body is bonded to the front and back of a metal shim, and both ends of the shim are placed in a rectangular notch formed on the substrate, and then molded. Thus, the electronic element and the piezoelectric body on the substrate are arranged on a single plane. For this reason, when the substrate is accommodated in the earphone, it is necessary to secure a large area of the substrate, which has been an obstacle to downsizing the earphone.
On the other hand, in the case of recognizing the sound through the bone conduction through the vibration of the piezoelectric diaphragm, it is necessary to generate a large vibration. For this purpose, the number of stacked layers or the number of piezoelectric diaphragms may be increased. However, in this case, since the piezoelectric diaphragm becomes larger and the electric capacity further increases, it is necessary to increase the output of the electronic element on the substrate. As a result, this has been an obstacle to downsizing the earphone.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a bone conduction earphone that can reduce the size of the earphone by devising the configuration of the vibration generation source.

  In order to solve the above problems, the configuration of the bone conduction earphone adopted by the present invention includes an earphone main body, a vibration generation source that is housed in the earphone main body and converts an external electric signal into mechanical vibration, and the earphone main body. In the bone conduction earphone provided to the user's pinna or the ear canal, the vibration generation source includes a substrate and a piezoelectric diaphragm, and the substrate is externally provided. A lead wire to which an electric signal is supplied is connected, and an electronic element constituting a circuit including an amplifier circuit is mounted. At least a part of the piezoelectric diaphragm is fixed to the substrate in a state of being separated from the substrate. It is characterized by being.

  In the bone conduction earphone, it is preferable that an opening hole that opens toward the auricle or the ear canal is formed in the ear insertion portion.

  In the bone conduction earphone, it is preferable that an insertion hole that allows the opening hole to be opened to the outside is formed between the earphone main body and the ear insertion portion.

  According to the present invention, by arranging the substrate and the piezoelectric diaphragm so as to overlap each other in a separated state, the vibration generating source can be reduced in size compared to Patent Document 1, and thus the bone conduction earphone itself can be reduced in size. Can do.

<Configuration of bone conduction earphone>
Preferred embodiments of the present invention will be described with reference to the drawings.
1 and 2 are views showing the appearance of the bone conduction earphone according to the present embodiment.
The bone conduction earphone 10 includes an earphone main body 11 that is formed into a hollow cross-sectional oval shape with a resin material (for example, synthetic resin such as ABS, PE, PP, and PVC), and an ear that is detachably attached to the earphone main body 11. An insertion portion 21 and a vibration generation source 31 housed in the earphone main body 11 are provided.

<Earphone configuration>
One end of the earphone main body 11 is provided with a cord cover 13 for extending the lead wire 12 to the outside, and a pattern terminal 35 of the substrate 32 is provided at one end of the lead wire 12 as shown in FIGS. A connector (not shown) connected to an external device is connected to the other end. Further, a pair of connecting projections 14, 14... That are connected to the connecting hole 24 of the ear insertion portion 21 are provided at a position facing each other on the other peripheral surface of the earphone main body 11. Further, the earphone main body 11 has a storage chamber 15 for storing the vibration source 31.

<Configuration of ear insertion part>
The ear insertion portion 21 is inserted into the user's pinna or external auditory canal, and is formed in a stepped cylinder shape with a resin material, and an opening hole 22 that opens toward one side (ear side) is formed at the center thereof. It is formed. Further, a plate-like attachment portion 23 is formed on the other side of the ear insertion portion 21, and by forming the attachment portion 23 corresponding to the bottom portion of the opening hole 22 in a rectangular shape, both sides of the attachment portion 23 have a half-moon shape. Insertion holes 25, 25 are formed.

  Further, the attachment portion 23 is provided with connection holes 24 and 24 that fit into the connection protrusion 14 of the earphone main body 11, and by selecting the connection protrusion 14, the ear insertion portion 21 can be selected with respect to either the left or right of FIG. 3. Can be attached.

<Configuration of vibration source>
Next, the vibration generating source 31 housed in the housing chamber 15 of the earphone main body 11 is a rectangular substrate 32 and a piezoelectric diaphragm that is partly fixed to the substrate 32 while being separated from the substrate 32. 41.

  On the surface of the substrate 32, electronic elements 33 constituting an amplifier circuit for generating a drive signal and the like are mounted, and pattern terminals 35, 35... Drawn from the wiring pattern 34 are formed on one side. The piezoelectric diaphragm 41 is fixed to the other side of the surface of the substrate 32 by an adhesive via a spacer 36. On the other hand, both ends of the back surface of the substrate 32 are fixed to the wall surface of the storage chamber 15 by adhesives 37 and 37.

  The piezoelectric vibration plate 41 is formed by laminating a plate-like piezoelectric material such as PZT (lead zirconate titanate), for example, in nine layers alternately with a metal plate (a plurality of bimorph structures). Four substantially “U” -shaped electrodes 42, 42... Are provided at the positions. Since these electrodes 42 are also in electrical contact with a plate-like piezoelectric body positioned between the piezoelectric diaphragms 41, by supplying a drive signal to each electrode 42, vibration is applied to each piezoelectric body. generate.

Here, the occurrence of vibrations in the piezoelectric diaphragm 41 will be described with reference to FIG.
FIG. 6 shows one plate-like piezoelectric body constituting the piezoelectric diaphragm 41. In this piezoelectric body, as shown on the right side of the upper stage, a strong magnetic field is applied to each electrode 42 to perform polarization processing. As a result, the polarization direction and the magnetic field direction are aligned in the longitudinal direction of the piezoelectric body, and distortion and stress are generated in a direction perpendicular to the polarization direction.
For this reason, when a positive sine wave of the drive signal is applied as in the middle stage, for example, the center of the piezoelectric body bends upward, and when a negative sine wave is applied as in the lower stage, the piezoelectric body The center of sag is bent downward, generating transverse vibration.

<Operation of bone conduction earphone>
Next, the operation of the bone conduction earphone 10 will be described.
An audio signal from the outside is transmitted to the substrate 32 through the lead wire 12, and a drive signal amplified by the electronic element 33 mounted on the substrate 32 is generated. This drive signal is generated by each electrode 42 of the piezoelectric diaphragm 41. To be supplied. The piezoelectric diaphragm 41 that has received the supplied drive signal starts to vibrate. The vibration of the piezoelectric diaphragm 41 is also transmitted to the substrate 32 through the spacer 36, and the whole vibration generation source 31 is vibrated to vibrate the earphone body 11. The vibration of the earphone main body 11 is transmitted to the user's external ear, and is converted into an electrical signal via the external ear via the cochlear organ / acoustic nerve and transmitted to the brain. Furthermore, the vibration of the ear insertion portion 21 is transmitted as an air conduction sound to the brain via the tympanic membrane and the cochlear organ / auditory nerve.
The above is the basic operation of the bone conduction earphone.

<Effect of bone conduction earphone>
Since the bone conduction earphone 10 according to the present embodiment includes the ear insertion portion 21 having the opening hole 22, the sound in the audible frequency range becomes air vibration due to the resonance action by the opening hole 22, and is used from the opening hole 22. Transmitted to the person's ear canal. On the other hand, for the sound in the relatively low frequency range, the mechanical vibration of the earphone body 11 is transmitted through the outer ear. As a result, it is possible to secure a wider frequency range compared to conventional bone conduction earphones, and the sound clarity is significantly improved.
It should be noted that the frequency for causing the resonance action can be derived from the relationship with the natural frequency of the earphone main body 11 set from the shape of the opening hole 22, the enclosure capacity of the storage chamber 15, and the like.

  Further, since the vibration generating source 31 is arranged so that the piezoelectric diaphragm 41 is overlapped with the substrate 32 in a separated state, the occupied area is larger than that in Patent Document 1 in which the substrate and the piezoelectric diaphragm are arranged on one plane. The bone conduction earphone 10 can be reduced in size.

  Furthermore, in the bone conduction earphone 10 according to the present embodiment, since the insertion holes 25 and 25 are formed between the earphone main body 11 and the ear insertion portion 21, external sound is aired through the insertion holes 25 and 25. It reaches the user's ear as vibration. Thereby, the user can recognize the sound generated from the earphone 10 while recognizing the external sound.

  In addition, since the vibration source 31 has a structure in which the piezoelectric diaphragm 41 is cantilevered with respect to the substrate 32, longitudinal vibration of the piezoelectric diaphragm 41 due to application of a drive signal can be efficiently generated. It is possible to provide a sound that can be easily recognized by the user.

<Modification>
(1)
The present invention is not limited to the bone conduction earphone 10 having the shape described in the above embodiment, but a substantially “C” -shaped clip 52 that rotates behind the ear at one end of the earphone main body 11 like an earphone 51 shown in FIG. 7. May be provided. Further, in the earphone 51, when the ear to be heard is switched between right and left, it is possible to remove the connecting hole 24 connected to the connecting protrusion 14 and replace it with the other surface.

(2)
The piezoelectric diaphragm 41 of the above embodiment is formed by laminating nine layers of piezoelectric bodies and providing four substantially “U” -shaped electrodes 42, 42... The number of stacked piezoelectric diaphragms 41 and the material thereof are not limited to this, and any piezoelectric diaphragm 41 that vibrates in the thickness direction according to the supplied drive signal may be used.

(3)
In the above-described embodiment, the piezoelectric diaphragm 41 is cantilevered with respect to the substrate 32. However, the present invention is not limited to this, and the piezoelectric diaphragm 41 may be supported on the substrate 32 at both ends. Good. However, in this case, a spacer or an adhesive having a high elastic modulus may be used so that the vibration of the piezoelectric diaphragm 41 is actively promoted.

(4)
In the above-described embodiment, the ear insertion portion 21 of the bone conduction earphone 10 is inserted at the boundary position between the user's pinna and the external auditory canal, but the tip end side of the ear insertion portion 21 is tapered. Alternatively, the user may be positively inserted into the ear canal.

(5)
In the said embodiment, although the earphone main body 11 was described as what was integrally formed with the resin material, you may comprise as a separable shape.

(6)
Since the earphone main body 11 according to the embodiment does not have an electromagnetic generation source that generates sound by a magnetic field, it can be used in a place where a strong magnetic field such as MRI is generated.

It is a front view which shows the external shape of the bone conduction earphone which concerns on embodiment. It is a side view which shows the external shape of the bone conduction earphone which concerns on the same embodiment. It is sectional drawing which shows the bone conduction earphone which concerns on the same embodiment. It is a figure which shows the external shape of the ear insertion part which concerns on the embodiment. It is a disassembled perspective view which shows the vibration generation source which concerns on the same embodiment. FIG. 6 is an explanatory diagram showing an operation of the piezoelectric diaphragm according to the same embodiment. It is a front view which shows the external shape of the bone-conduction earphone by a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,51 ... Bone conduction earphone, 11 ... Earphone main body, 21 ... Ear insertion part, 22 ... Opening hole, 23 ... Mounting part, 25 ... Insertion hole, 31 ... Vibration source, 32 ... Substrate, 33 ... Electronic element, 41 ... piezoelectric diaphragm, 42 ... electrode, 52 ... clip.

Claims (3)

The earphone body,
A vibration source housed in the earphone body and converting an electrical signal from the outside into mechanical vibration;
In the bone conduction earphone provided in the earphone main body and comprising an ear insertion portion that is inserted into the user's pinna or the ear canal,
The vibration generation source includes a substrate and a piezoelectric diaphragm,
The substrate is connected to a lead wire to which an electric signal is supplied from the outside, and an electronic element constituting a circuit including an amplifier circuit is mounted, and the piezoelectric diaphragm is at least separated from the substrate. A part of the bone conduction earphone is fixed to the substrate. The bone conduction earphone according to claim 1,
The ear insertion part is formed with an opening hole that opens toward the auricle or the ear canal. The bone conduction earphone according to claim 2,
A bone conduction earphone characterized in that an insertion hole is formed between the earphone main body and the ear insertion portion to allow the opening hole to be opened to the outside.

Images