JP2010273084A - Bone conduction transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bone conduction speaker with excellent acoustic characteristics and quality. <P>SOLUTION: The bone conduction speaker includes: a frame with a vibration transmission plate; a pot-shaped yoke which is fixed to an inner wall of the frame by a movable support body; a magnet which is fixed to the bottom surface of the yoke; and a coil, one end of which surrounds at least a part of the side surface of the magnet, and the other end of which is fixed to the vibration transmission plate. The bone conduction speaker is used to be brought into contact with human skin. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bone conduction transducer and a bone conduction headset including the bone conduction transducer.

  As a bone conduction system, a piezoelectric element system, a giant magnetostrictive element system, and a coil element system are generally known. Among these, the coil element method is expected to be applied to various uses because it can be used by directly connecting to the earphone terminal. Conventionally, bone conduction transducers have been mainly used for hearing aid, but in recent years, the demand for audio applications has increased, and development of bone conduction transducers with good acoustic characteristics and quality has been requested from various fields. Yes. For example, Patent Document 1 discloses a bone conduction earphone that fixes a coil on the inner surface of an upper wall of a frame, vibrates magnets arranged on the inside and outside of the coil, and transmits the vibration via a vibration transmission cushion. Has been.

JP 2008-131470 A

  However, as disclosed in Patent Document 1, in the case of a system in which the coil side is fixed to the frame, the magnet side is vibrated, and the vibration transmitting portion provided on the magnet side is brought into contact with the human body, the following is performed. There was a problem. That is, when the vibration transmitting portion provided on the magnet side is strongly pressed against the human body in order to increase the sensible volume, there is a problem in that the sensible volume is reduced because the vibration operation of the magnet is suppressed. In order to solve this problem, it is possible to adopt a structure in which an appropriate space is provided between the magnet and the human body to freely vibrate the magnet. However, in such a structure, unnecessary resonance and airway sound can be used. There was a bad effect that would occur.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a bone conduction transducer having good acoustic characteristics and quality.

  It is another object of the present invention to provide a bone conduction headset including the bone conduction transducer.

  The bone conduction transducer according to the present invention includes a frame having a vibration transmission plate, a pot-shaped yoke fixed to the inner wall of the frame by a movable support, a magnet fixed to the bottom surface of the yoke, and one end of the magnet And a coil that surrounds at least a part of the side surface of the, and the other end of which is fixed to the vibration transmission plate. When the bone conduction transducer is used, the vibration transmission plate is brought into contact with human skin.

  The bone conduction transducer may further include a weight bonded to the magnet. The weight may be a magnetic material. Further, the height of the side wall of the yoke may be larger than the sum of the thickness of the magnet and the thickness of the weight.

  According to the bone conduction transducer of the present invention, it is possible to provide a bone conduction transducer having good acoustic characteristics and quality.

It is sectional drawing showing the cross section of the bone conduction transducer by this invention. It is sectional drawing showing each site | part of the bone conduction transducer by this invention. (A) is a schematic perspective view of the headset provided with the bone conduction transducer shown in FIG. (B) is a schematic view when a person wears the headset shown in (a).

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view showing a section of a bone conduction transducer 100 according to the present invention. FIG. 2 is a cross-sectional view showing each part of the bone conduction transducer 100. As shown in FIGS. 1 and 2, the bone conduction transducer 100 includes an upper frame 101, a movable support body 102, a yoke 103, a magnet 104, a weight 105, a coil 106, a lower frame 107, vibrations, and the like. And a transmission plate 108.

  The upper frame 101 is a case member made of, for example, a material such as plastic having a space for accommodating the magnet 104 and other members by coupling with the lower frame 107, for example. In the center of the upper frame 101, an opening 101a for restricting the movement of the magnet 104 to some extent is provided. By providing the opening 101a, the same effect as the air duct of the speaker box can be obtained and the sound quality can be improved. In addition, the upper frame 101 is provided with a plurality of attachment portions 101 b for fixing the movable support 102 at regular intervals along the outer periphery of the upper frame 101, for example.

  The lower frame 107 also has a dish shape and is a case member made of a material such as plastic having a space for accommodating the magnet 104 and other members by being coupled to the upper frame 101. An opening 107a is provided at the center of the lower frame 107, and a ring-shaped protrusion 107b is provided so as to surround the opening 107a. A vibration transmission plate 108 is fitted inside the protrusion 101 b and closes the opening 107 a of the lower frame 107.

  Hereinafter, the entire frame in which the upper frame 101 and the lower frame 107 are coupled by a mechanical mechanism such as an adhesive or a fitting mechanism is simply referred to as a frame 109. The lower frame 107 is curved from its opening 107a to a dish-shaped edge 107c. Since the outer shape of the lower frame 107 is curved, it is possible to stably contact any head shape. The thickness of the frame 109 is not limited and may be set appropriately according to the product specifications. Further, a decoration or other structure may be provided outside the frame 109 as appropriate.

  The movable support 102 is a support for connecting and fixing the yoke 103 to the upper frame 101, and is a damper formed by punching a metal plate such as copper, for example, with a press. The movable support 102 has, for example, an annular structure in which the yoke 103 can be fitted in the central portion thereof, and a plurality of fixed portions 102a are provided at positions extending outward from the annular structure. Are provided at equal intervals, for example. Each of the fixing portions 102 a is fixed to the attachment portion 101 b of the upper frame 101 by fixing pins or screws 110. The yoke 103 fixed to the movable support 102 can move up and down in the direction of the upper frame 101 or the lower frame 107 by the bending of the movable support 102. In particular, by providing the fixing portion 102a at a position extending outward from the annular structure of the movable support 102 and fixing it to the attachment portion 101b of the upper frame 101, the acoustic characteristics can be improved.

  The yoke 103 is a bottomed cylindrical shape (so-called pot type) yoke made of a magnetic metal material such as soft iron. It is supported in the space of the frame 109 by being fitted into the annular portion. A ring-shaped protrusion 103 a is provided on the side surface of the yoke 103, and this protrusion 103 a is bonded and fixed to the movable support 102. The position of the protrusion 103a on the side surface of the yoke 103 is not limited, and can be set as appropriate according to the shape of the frame 109 and the like. The bottom 103b of the yoke 103 is flat so that the magnet 104 can be attached.

  The magnet 104 is a cylindrical permanent magnet having predetermined magnetism. One surface of the magnet 104 is fixed to the approximate center of the bottom 103b of the yoke 103 with an adhesive. The diameter of the magnet 104 is smaller than the diameter of the bottom 103 b of the yoke 103, and a ring-shaped space exists between the side surface of the fixed magnet 104 and the side wall of the yoke 103. The surface fixed to the bottom 103b of the yoke 103 may be either the S pole side or the N pole side of the magnet 104. For example, the S pole side surface of the magnet 104 is fixed to the bottom 103b of the yoke 103.

  The weight 105 is a columnar weight having substantially the same diameter as the magnet 104, and one surface thereof is bonded to the other surface of the magnet 104 with an adhesive. The weight 105 is a magnetic material such as iron oxide, chromium oxide, cobalt, or ferrite. Normally, the diameter of the weight 105 is the same as the diameter of the magnet 104, but may be relatively large or small as necessary.

  By changing the size (or mass) of the weight 105, the substantial mass of the magnet 104 can be changed. For example, the mass can be changed by increasing or decreasing the thickness of the weight 105 in the cylinder axis direction. Changing the substantial mass of the magnet 104 changes the frequency characteristics and sound quality of vibration. That is, the frequency characteristics and sound quality can be easily changed by changing the size (or mass) of the weight 105 for each product type. Note that the mass may be changed by further attaching at least one other weight to the weight 105.

  For example, as shown in FIG. 1, the coil 106 is a so-called voice coil having a cylindrical shape in which one end surrounds at least a part of the side surface of the magnet 104 and the weight 105 and the other end is fixed to the vibration transmission plate 108. In order to obtain a predetermined inductance, the coil 106 is obtained by winding an electric wire such as a copper wire around a cylindrical bobbin 106b made of a material such as plastic or aluminum by a predetermined number of turns. Hereinafter, the part is referred to as a winding portion 106a. In addition, you may perform suitably the process of embedding and fixing the electric wire wound around the bobbin with resin.

  For example, as shown in FIGS. 1 and 2, the winding portion 106 a is located at the end of the bobbin 106 b on the magnet 104 side, and at least a part of the winding portion 106 a is between the side surface of the magnet 104 and the weight 105 and the side wall of the yoke 103. It is located along the formed ring-shaped space. Further, an end portion on the opposite side of the winding portion 106a (hereinafter referred to as a fixing portion 106c) is fixed to the vibration transmission plate 108. The fixing portion 106c is fixed to the vibration transmission plate 108 by a mechanical mechanism (not shown) such as a fitting mechanism or a meshing mechanism provided in each of the fixing portion 106c and the vibration transmission plate 108.

  The thickness of the magnet 104 and the weight 105 in the axial direction of the cylinder is appropriately adjusted in order to obtain a desired frequency characteristic and sound quality, so that the winding portion 106a is positioned so as to surround only a part of the side surface of the weight 105. There are also cases where the magnet 104 is positioned so as to surround at least a part of the side surface of the magnet 104 and the entire side surface of the weight 105. From the viewpoint of effectively obtaining the action of the magnetic field, the height h1 of the side wall of the yoke 103 is larger than the sum of the thickness d1 of the magnet 104 in the cylinder axis direction and the thickness d2 of the weight 105 in the cylinder axis direction. It is preferable to do this.

  For example, a wiring cord (not shown) is connected to the coil 106 through a through hole (not shown) provided in the upper frame 101. When power is supplied to the coil 106 via the wiring cord, the magnet 104 is connected. The magnet 104 and the coil 106 vibrate at a predetermined frequency by the action of the magnetic field generated between the coil 106 and the coil 106.

  The vibration transmission plate 108 is a vibration plate made of a material such as circular plastic or aluminum having a diameter slightly larger than the diameter of the cylindrical coil 106 so as to surround the opening 107 a of the lower frame 107. It is fitted inside a protrusion 101b provided in a ring shape. A winding portion 106a of the coil 106 is fixed to one surface of the vibration transmission plate 108, and the vibration of the coil 106 is transmitted to the skull via the human skin brought into contact with the other surface of the vibration transmission plate 108. Take a role. The thickness of the vibration transmission plate 108 is appropriately determined according to conditions such as the material.

  Hereinafter, the operation of the bone conduction transducer 100 will be described.

  First, the vibration transmission plate 108 of the bone conduction transducer 100 is brought into contact with, for example, the temple portion of the human head. At this time, the curved surface from the opening 107a to the edge 107c of the lower frame 107 may be appropriately brought into contact according to the shape of the human head. For example, a current for generating vibration corresponding to sound such as music is supplied to the coil 106 from a wiring cord (not shown).

  When a current is supplied to the coil 106, the magnetic field generated between the magnet 104 and the coil 106 causes the magnet 104 and the coil 106 to have a frequency according to the amount of the current and the total mass of the magnet 104 and the weight 105. Vibrates. The magnet 104 fixed to the bottom 103b of the yoke 103 vibrates mainly along the cylinder axis direction by the bending of the foot portion 102b of the movable support 102. The coil 106 vibrates mainly along the cylindrical axis direction, and the vibration is transmitted to the vibration transmission plate 108 fixed to the coil 106 by the fixing portion 106c.

  The vibration having a relatively high frequency component is mainly transmitted from the coil 106 to the vibration transmitting plate 108. On the other hand, vibration with a relatively low frequency component is transmitted to the frame 109 via the movable support 102 mainly by vibration of the magnet 104. These vibrations are transmitted to the skull by the vibration transmitting plate 108 and the frame 109 brought into contact with the human skin. Since the vibration is transmitted to the skull via the human skin, even a person with hearing loss can recognize the sound.

  As described above, the bone conduction transducer of the present invention has a structure in which a diaphragm is provided on the coil side, and the coil side is brought into contact with the human head to transmit vibration to the skull. In the case of a conventional structure in which an appropriate space is provided between the magnet and the human body to automatically vibrate the magnet, the space causes unnecessary airway sound, resulting in a decrease in sound quality. In contrast, the structure of the present invention in which vibration is transmitted to the skull via the diaphragm coupled to the coil does not generate unnecessary airway sound, and the bone conduction transducer is pressed against the human skin. Regardless of this, stable sound quality can be obtained, and good acoustic characteristics and quality can be obtained.

  Further, by adopting such a structure of the present invention, a weight can be attached to one side of the magnet (the side on which the coil is disposed). By changing the size and mass of the weight for each product type, the substantial mass of the magnet can be changed, and desired frequency characteristics and sound quality required for the product can be easily adjusted. The columnar weight is affixed to one side of the magnet so that it fits in the space inside the cylindrical coil, and the substantial mass of the magnet can be easily changed by changing the height of the column of the weight. be able to. Conventionally, in order to change the frequency characteristics and sound quality, it was necessary to change the structure and material of the bone conduction transducer, but according to the present invention, these can be easily adjusted by changing the size and mass of the weight. Cost reduction can be realized. In addition, by changing the shape and thickness of an inexpensive weight instead of changing the shape and thickness of a relatively expensive magnet, the same purpose of changing the frequency characteristics and sound quality can be achieved, further reducing the cost. Can be reduced.

  Further, by adopting such a structure of the present invention, the relationship between the height of the side wall of the pot-shaped yoke and the thickness of the columnar magnet and the weight attached thereto can be freely set. From the viewpoint of effectively obtaining the action of the magnetic field, the height of the side wall of the yoke is preferably larger than the sum of the thickness of the magnet and the thickness of the weight.

  Further, by adopting such a structure of the present invention, the outer shape of the frame that is brought into contact with human skin can be curved. In the case of the conventional bone conduction transducer that contacts the magnet side to the human skin, the shape of the magnet is generally flat, so the contact surface to the human skin must also be flat, and the outer shape of the frame is curved. I could not. On the other hand, according to the bone conduction transducer of the present invention, since the cylindrical coil side is brought into contact with the human skin, the degree of freedom in forming the frame on the contact side can be increased. By curving the outer shape of the frame as in the present invention, it is possible to stably make contact with any human head shape and transmit vibrations efficiently.

  FIG. 3A is a schematic perspective view of a headset 200 including the bone conduction transducer 100 shown in FIG. FIG. 3B is a schematic diagram when a person wears the headset 200. The headset 200 includes one bone conduction transducer 100 on each of the left and right sides, which are connected by a connecting member 210 made of a material such as plastic. The connecting member 210 is provided with a through hole (not shown) for passing a current supply cord (not shown). The cord passes through the through hole and the space of the connecting member 210 and is coiled. 106 is connected. A current is supplied to the coil 106 by connecting a power supply terminal (not shown) provided at one end of the cord to a power supply source. As shown in FIG. 3B, the headset 200 is usually mounted so that a part of the connecting member 210 is hooked on the ear 300 and the vibration transmitting plates 108 of the left and right bone conduction transducers 100 are in contact with the temple portions. The

  In the above-described embodiment, the bone conduction transducer 100 is brought into contact with the temple portion of the human head. However, the portion with which the bone conduction transducer 100 is brought into contact is not limited to the temple portion. In other words, any part that can conduct bone may be brought into contact with any part.

  The bone conduction transducer 100 can also be used for bone conduction headphones, bone conduction mobile phones, bone conduction hearing aids or earphones, bone conduction transceivers, bone conduction intercoms, for example.

100 Bone conduction transducer 101 Upper frame 102 Movable support 103 Yoke 104 Magnet 105 Weight 106 Coil 107 Lower frame 108 Vibration transmission plate 109 Frame 110 Fixing pin (fixing screw)
200 Headset 210 Connecting member 220 Cord 230 Power terminal

Claims (9)

A bone conduction transducer that transmits physical vibrations through human bones,
A frame with a vibration transmission plate;
A pot-shaped yoke fixed to the inner wall of the frame by a movable support;
A magnet fixed to the bottom of the yoke;
A bone conduction transducer comprising: a coil having one end surrounding at least a part of a side surface of the magnet and the other end fixed to the vibration transmission plate.   The bone conduction transducer according to claim 1, further comprising a weight bonded to the magnet.   The bone conduction transducer according to claim 2, wherein the weight is a magnetic body.   The bone conduction transducer according to claim 3, wherein a height of the side wall of the yoke is larger than a sum of a thickness of the magnet and a thickness of the weight.   A headset or headphones comprising the bone conduction transducer according to any one of claims 1 to 4.   A mobile phone comprising the bone conduction transducer according to any one of claims 1 to 4.   A hearing aid or an earphone comprising the bone conduction transducer according to any one of claims 1 to 4.   A transceiver comprising the bone conduction transducer according to any one of claims 1 to 4.   An intercom comprising the bone conduction transducer according to any one of claims 1 to 4.

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