JP6471393B2 - Inner ear type earphone - Google Patents

Description

Detailed Description of the Invention

INDUSTRIAL APPLICABILITY The present invention provides an inner-ear type earphone that can be used in an MRI having a noise reduction function capable of listening to good voice and music in a noisy environment such as MRI having a high magnetic field and improving voice clarity and sound pressure level. About.

For example, Patent Document 1 discloses a structure in which a vibrating body composed of a laminated piezoelectric actuator element or a laminated bimorph vibrator is embedded in a rod-like member 13 formed of a member such as silicon rubber or urethane rubber inserted into the ear canal. The earphone that functions as an earplug when inserted into the ear canal, guides sound waves to the eardrum by vibration of the rod-like member, and transmits the vibration of the rod-like member as bone transmission through the cartilage near the inner wall of the ear canal Is disclosed.

However, this earphone is limited in vibration because the vibrator is embedded in the resin, and an elastic body having a sound absorbing action is interposed as bone conduction, so that acoustic conversion efficiency and transmission efficiency are poor. There were disadvantages.

Further, Patent Document 2 discloses an earphone having a configuration similar to that of Patent Document 1 corresponding to the rod-shaped member of Patent Document 1 and having a through-hole provided in the center. Although it is the structure which can hear an external sound through a hole, since the structure is the same as that of Patent Document 1, the sound conversion efficiency is poor and the sound quality cannot be varied according to preference.

In Patent Document 3, an ear pad, a part of which is inserted into the ear canal, a cylindrical tubular body, an extending portion integrally provided in the tubular body, and a piezoelectric element attached to the extending portion are provided and transmitted. A member is formed, and a hole penetrating the ear pad and the cylindrical body is provided so that an external sound can be heard. Sound vibration is transmitted to the eardrum with the ear pad, and the tragus is brought into contact with the tragus with the transmission member. A device that attempts to transmit sound also by cartilage vibration via a cable is disclosed.

However, what is disclosed in this Patent Document 3 is mainly for contacting the tragus and transmitting the reproduced sound, and in which the ear pad 3 made of an elastically deformable member and the vibrating portion 6 are inserted into the ear canal. However, since the entire piezoelectric element is attached to the extending portion 2a, the conversion efficiency is poor, and the sound quality cannot be changed other than changing the entire material.

JP 2009-232443 A JP 2014-107828 A JP 2014-146949 A

The earphones described in Patent Documents 1 and 2 are mainly sound reproduction mainly of cartilage vibration with respect to the ear canal because the vibrating body has a structure arranged in parallel with the ear canal on a member inserted into the ear canal. Since the child is embedded in the resin, the vibration is limited, and since the elastic body has a sound absorbing action as bone conduction, there are disadvantages such as poor acoustic conversion efficiency and transmission efficiency.

In addition, what is disclosed in Patent Document 3 is intended to transmit sound also by cartilage vibration through the tragus by contacting the tragus with a sound signal by air propagation and a transmission member. Since the entire element is attached to the extending portion 2a, the acoustic conversion efficiency is poor.

In addition, most high-quality earphones called hi-fi use a magnetic metal and a magnetic circuit to send a sound wave to the ear canal using a speaker that vibrates a diaphragm with an electric signal, and vibrates the eardrum with sound waves. For this reason, in the conventional earphone, a sound source is always present at the ear, and a strong sound pressure is applied to the eardrum.

In this case, the sound pressure level may reach from 90 dB to 100 dB, and this sound pressure level is the same as when listening to the passing sound of a train under the card.
Therefore, these earphones have problems such as ear fatigue when listened to for a long time, and when hearing at a high volume, the function of the ear is damaged, resulting in hearing loss. In order not to return to the original state, it was a big social problem that young people who often listen to music with earphones became deaf.
Also, conventional earphones use metal materials for the speaker frame and magnetic metals for the magnetic circuit as materials, and when these materials are used for MRI, these materials are attracted by the high magnetic field of the MRI and cause serious damage to the device. At the same time, the influence on the captured image cannot be ignored.

In order to eliminate the drawbacks of such conventional earphones, bone conduction, cartilage conduction, etc. as shown in Patent Documents 1 to 3 are provided, but there are few acoustically satisfactory ones, and wide-band reproduction, that is, high-quality reproduction. There was a fault such as not suitable for.

The present invention realizes a high sound quality earphone that is difficult to be obtained by a bone-conduction (cartilage conduction) type earphone even when listening for a long time while using bone conduction using a non-magnetic piezoelectric element, and is difficult to be deaf. The present invention provides an earphone, a cylindrical case having an L-shaped outer shape, a flat plate-like vibration element having one end fixed to one end of the case and arranged in a cantilever shape toward the inside of the case, and the vibration The diaphragm attached integrally with the element and the other end of the case are inserted so as to protrude, and the other end is integrated with the vibration element and the free end of the diaphragm inside the case. Consists of a joined vibration tube and earplugs covering a portion protruding from the case of the vibration tube, and all constituent materials including a signal line for supplying an electric signal to the vibration element are made of a non-magnetic material. It is characterized by It is an inner earphone.

In the inner ear type earphone of the present invention, the vibration element and the vibration plate are fixed to the end of the case in a cantilever shape, and the periphery of the vibration element and the vibration plate is arranged in a space in the pipe-shaped case so that vibration is not transmitted to the case. In this way, all vibration energy can be transmitted to the vibration tube, so that the vibration that is attenuated by being transmitted to the case is reduced, and the free ends of the vibration element and the diaphragm are further vibrated with respect to the ear. By attaching to the end of the case of the vibration tube that transmits the vibration, it is possible to increase the range in which the vibration element and the diaphragm vibrate, which has the effect of increasing the vibration efficiency and the electroacoustic conversion efficiency. is there.

Further, in the earphone of the present invention, vibration efficiency and the like can be increased as compared with conventional bone conduction, and also air vibration can be generated not only by bone conduction but also by vibration of the vibration element and the diaphragm. Since the sound pressure level is improved and the vibration of the vibration tube itself can be transmitted to the ear as a bone electric motor. It can be heard clearly even under noisy conditions.

Furthermore, in the earphone of the present invention, as described above, the vibration element and the vibration plate are fixed to the end of the case in a cantilever shape, and the free end thereof is attached to the end of the vibration tube that generates sound. By adopting a configuration that can generate not only bone conduction but also air vibration with a vibrating body, it is a drawback of bone conduction that "requires greater drive power than earphones" It is possible to improve the disadvantages such as “unusable”, “not suitable for reproduction of wideband sound”, “difficult to hear for hearing-impaired hearing person”, “however, hearing aid tends to cause howling with hearing aid”.
In addition, by providing the case with an air hole that communicates the inside and outside of the case, the vibration element and the diaphragm can vibrate without receiving air resistance, so that the efficiency of the earphone itself is further improved and the sound quality is improved. Is.

Furthermore, by providing an earplug with a sound absorbing material inserted into the ear canal when inserted into the ear canal and having a hole penetrating in the center, the external noise is blocked by closing the ear canal with a soundproof material. Therefore, even when listening to music or the like under the noise inside the MRI, it is possible to listen in a state where the noise is low.

Further, in the present invention, since all parts of the earphone can be configured with a non-magnetic material, it can be used even in a place where the magnetic material cannot be used in the MRI gantry (head coil), Furthermore, when the earphone is worn on the ear in the gantry, the earphone may come off. However, in the present invention, noise can enter from the gap between the earphone and the ear by attaching the anti-slip plate to the earphone case. Therefore, it is possible to construct a good use listening environment inside the MRI.

The inner earphone of this invention is shown, (A) is a front view (B) is a sectional side view. In another embodiment of the inner earphone of the present invention, (A) is a front view and (B) is a side sectional view. FIG. 4A is a front view of a displacement stopper (A) for preventing displacement when the inner earphone of the present invention is worn, and FIG. It is a conceptual diagram which mount | wears with a slip stopper in the inner earphone of this invention. It is a photograph which shows the state with which the inner earphone of this invention was mounted | worn with a person's ear. It is a figure which shows the conventional earphone.

Embodiments of an inner earphone of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following examples.
FIG. 1 is a first embodiment showing a basic form in an embodiment of an inner earphone of the present invention, (A) is a front view, and (B) is a side sectional view.
The case 1 is a cylindrical pipe having an L-shaped cross section, and one is formed so as to be thinner stepwise than the other.

Reference numeral 2 denotes a structure including a vibration element 2 composed of a piezoelectric bimorph element, a piezoelectric actuator element, and the like, and a vibration plate 3 attached to the vibration element 2 by a method such as adhesion. The diaphragm is made of a material such as paper or resin, and enhances the vibration of the vibration element 2.
The structure including the vibration element 2 and the vibration plate 3 is fixed at one end to the narrow end of the case by a resonance stopper 8 made of an elastic body, and the other end is an acoustic cavity that is a space in the case 1. 1a is arranged so as not to come into contact with the inner wall of the case 1, and an end portion configured to be able to freely vibrate in a cantilever shape of a structure including the vibration element 2 and the vibration plate 3 is an end portion of the case 1. It is bonded to the end of the vibration tube 4 made of a hollow pipe inserted from the above.

The vibration tube 4 is composed of a pipe made of plastic or the like, and vibrates by adhering an end portion in the case 1 to a structure including the vibration plate 3 and the vibration element 2. In addition, the vibration tube 4 emits sound by air vibration and is directly transmitted to the ear by bone conduction (cartilage conduction). It is.

6 is attached to a portion of the vibration tube 4 that protrudes outside the case 1 and is made of an elastic material such as a silicone tube that allows the earphone to be worn with a soft feel when inserted into the ear canal. The earplug has a sound emission port 6a communicating with the hollow portion 5 of the vibration tube 7 at the center thereof, and is attached to the vibration tube 7 by the sound emission port 6a.
The earplug 6 absorbs high-frequency white noise, which is acoustically noise, so that it is also important in terms of sound quality, and is essential under MRI noise.
Reference numeral 9 denotes a lead wire for supplying a signal to the vibrator. One end of the lead wire is electrically coupled to the vibrator 2, and an electric signal such as music is supplied to the vibration element 2 from an acoustic device or the like. The vicinity of the connecting portion between the lead wire 9 and the vibration element 2 is fixed in a state where it is acoustically shielded from the case 1 so that the vibration of the case is not transmitted to the vibration element 2 by a resonance stopper 8 made of a sound absorbing material such as urethane. It is what is done.

In such a configuration, when an electric signal is supplied to the vibration element 2, the vibration element 2 vibrates integrally with the vibration plate according to the electric signal, and vibrates the vibration tube 4 to which the end portion is coupled.
In this embodiment, when the earphone is inserted into the ear canal, the ear plug 6 contacts the ear canal 9 when the earphone is inserted into the ear canal. ) (Y direction in FIG. 2) and air vibration generated by the vibration of the vibrating tube 3 itself is transmitted to the eardrum through the sound outlet (X direction in FIG. 2), and air vibration and bone conduction (cartilage). The sound is heard by the listener as sound.

In the present invention, since the vibration tube 4 has a larger volume and mass than the structure of the vibration element 2 and the vibration plate 3, the vibration generated by the vibration body is slight. Therefore, it is possible to provide an earphone that has little sound pressure applied to the eardrum and requires very little fatigue, and that does not get tired even when used for a long time.

Further, in the present invention, one end of the vibration element 2 and the vibration plate 3 is fixed near the end of the case 1, and a cantilever structure is provided in which a portion other than the fixed portion is positioned in the space. As a result, the vibration energy of the vibration element 2 can be effectively utilized, and an electric signal can be efficiently converted into an audio signal.

FIG. 2 shows a case 1 provided with an air hole 10 in the case 1 of the embodiment shown in FIG. 1, and the inside and the outside of the case 1 are spatially communicated with each other by the air hole 10. Since the vibration of the structure composed of the diaphragm 3 can be vibrated without being influenced by the viscosity of the air, an earphone with better acoustic conversion efficiency can be provided.

As shown in FIG. 3, when the inner ear type earphone of the present invention is used for a person to be examined by MRI, the head of the subject is inserted into the gantry after wearing the earphone, so that the earphone is correctly attached. Even when the head is inserted into the gantry, there is a stopper plate 11 for improving the problem that the earphone is displaced and MRI noise enters the subject's ear through the gap. An elastic mounting portion 11b is provided on the flat plate portion 11a as shown in FIG. 4 so that the cross-section arc shape faces each other. As shown in FIG. 4, the earphone case 1 is inserted into the mounting portion 11b and attached to the earphone. It is.

FIG. 5 shows a photograph when the earphone of the present invention is worn on a person's ear. The flat surface of the flat plate portion 11a of the stopper plate 11 comes into contact with the cheek, and the earphone is displaced or lifted. It is possible to prevent a gap from being generated between the earphone and the ear.

Therefore, even if this earphone is worn in a great amount of noise when the MRI is operating, the earplug 6 made of the sound absorbing material can prevent the MRI noise from reaching the ear, The sound from the earphone can be heard from the hollow portion 5 of the vibration tube 4 through the sound outlet 6a of the earplug 6 and can be directly transmitted as vibration to the ear through the case 1 and the earplug 6. Music and the like can be heard not only by vibration sound but also by bone conduction (cartilage conduction), and earphones with good sound quality can be provided.

In the present invention, the material of the vibration tube 4 has been described as plastic, but the sound quality of the earphone can be changed arbitrarily by changing it to metal or the like.
Of course, the sound quality can be changed by changing the inner diameter of the hollow portion 5 of the vibration tube 4 or changing the cross-sectional shape thereof.

Furthermore, by changing the shape of the ear plug 6 or making the material more highly sound-absorbing, it is possible to further prevent noise inside the MRI and to improve the wearing feeling. .

DESCRIPTION OF SYMBOLS 1 Case 2 Vibrating element 3 Diaphragm 4 Vibrating tube 5 Hollow part 6 Ear plug 6a Sound emission port 7 Anti-vibration material 8 Resonance stop 9 Signal line 10 Air hole 11 Detachment plate

Claims (6)

An L-shaped cylindrical case, a flat plate-like vibrator having one end fixed to one end of the case and arranged in a cantilever shape toward the inside of the case, and a diaphragm integrated with the vibrator And a hollow pipe-like vibration that is inserted so that a part protrudes from the other end portion of the case, and the other end portion is integrally joined to the free end portion of the vibrator and the diaphragm inside the case. An earplug made of a sound-absorbing material inserted into a tube, a portion protruding from the case of the vibration tube, and configured to communicate with a hollow portion of the vibration tube in the center, and an electric signal to the vibrator An inner earphone characterized by comprising a signal line to be supplied. 2. The inner earphone according to claim 1, wherein the vibration tube is made of a hard material made of plastic. The inner earphone according to claim 1, wherein the vibration tube is attached to the case via a vibration preventing material between the vibration tube and the case. The inner earphone according to claim 1, wherein a space is provided between the vibrator and the case. The inner earphone according to claim 1, wherein an air hole is provided in a part of the case to increase the vibration efficiency of the vibrator inside the case. Soundproofing due to the displacement of the mounting position when a C-shaped mounting section and a fixed holder provided with a flat plate-shaped detent plate on the face-contacting section are mounted near the base of the case and the inner earphone is mounted on the ear. The inner earphone according to claim 1, wherein a decrease in performance is prevented.