JP2009153032A - Micro speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro speaker that is a speaker device thinned while maintaining output. <P>SOLUTION: The micro speaker 1 presents a slim shape of which the planar shape is approximately rectangular, a short-axis X-direction cross section of a yoke 2 is a recessed shape and a long-axis Y-direction cross section thereof is a plate-like shape. A magnet 3 is fixed in the center of the yoke 2, and a top plate 5 is fixed on the magnet 3. A magnet 4 is fixed while being spaced by a gap (g) on the yoke 2 outside the magnet 3 in a Y-axis direction. A top plate 6 is fixed on the magnet 4. The outer circumference of the yoke 2 is fixed on a frame 8. The magnet 3 and the magnet 4 are magnetized in perpendicularly opposite directions, a magnetic circuit 9 passing through the yoke 2, the magnet 3 and the top plate 5 is formed on the Y-axis direction cross section, and a magnetic circuit 10 passing through the yoke 2, the magnet 4, the top plate 6 and the top plate 5 is formed in the X-axis direction. A coil 7 fixed on a diaphragm that is not shown in the figure, faces the gap (g) that is a magnetic gap. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a microspeaker which is incorporated in a small mobile communication device such as a mobile phone and is intended to notify an incoming call by a ringtone or a loud sound.

Conventionally, in general, an internal magnet type speaker having a magnet and a top plate inside a concave section yoke, and an outer magnet type speaker having a magnet and a top plate on the outer periphery of the convex section yoke, There is. A micro speaker, which is a small electroacoustic transducer, is widely used for mobile phones and the like. In such a small speaker, a magnetic circuit in which a cuboid magnet and a top plate are arranged on the outer peripheral portion of a rectangular parallelepiped yoke having a raised central portion is assumed to be compatible with high sound pressure while maintaining a small size. There is an external magnet type speaker (see, for example, Patent Document 1). In addition, there is a speaker having a magnetic circuit in which a cylindrical magnet and a top plate are arranged outside a top plate and a cylindrical magnet as an example of an electromagnetic attraction force increased by increasing the magnet volume (for example, Patent Documents). 2, see Patent Document 3).
JP 2004-266337 A (FIG. 1) JP 2007-189270 A (FIG. 1) Utility Model Registration No. 3098542 (FIG. 1)

  However, the speaker of Patent Document 1 has a problem that the magnetic efficiency of the two sides where the magnet and the top plate are not installed is low. In the speakers of Patent Documents 2 and 3, the planar shape is a rectangle or a length other than a circle. There is a problem that it is difficult to adapt when the shape is circular or elliptical, or when the dimension on the short axis side is insufficient.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to effectively utilize the space of a slim speaker whose planar shape is substantially rectangular, substantially oval, or substantially elliptical. Another object of the present invention is to provide a micro speaker which is a thin speaker device while maintaining output.

  The means of the present invention for achieving the above-mentioned object is a micro speaker having a planar shape of substantially rectangular, substantially oval, or substantially elliptical, and has a magnetic circuit portion in which a yoke, a magnet and a top plate are combined fixed. In a micro speaker comprising a frame, a diaphragm fixed to the frame, and a coil that is fixed to the diaphragm and faces a magnetic gap that is a gap between the yoke and the top plate, the yoke has a short-axis cross section. Is a concave shape, and the cross section in the long axis direction is a flat plate shape. A first magnet and a first top plate are fixed on the magnet at the center of the yoke. The first magnet of the yoke A second magnet and a second top plate are fixed on the magnet with a gap in the major axis direction, and the first magnet and the second magnet are perpendicular to each other. A first magnetic circuit that is magnetized and passes through the yoke, the first magnet, and the first top plate, and a second magnet that passes through the yoke, the second magnet, and the second top plate. A circuit is formed.

  The first top plate, the first magnet, and the yoke are formed with an open hole penetrating the first top plate, the first magnet, and the yoke.

  Further, a through hole is provided in the yoke under the coil.

  The yoke and the frame are integrally formed.

  According to the present invention, the planar shape is a micro speaker having a substantially rectangular shape, a substantially oval shape, a substantially oval shape, or the like, and a frame to which a magnetic circuit unit combining a yoke, a magnet, and a top plate is fixed, and the frame is fixed to the frame. In the microspeaker comprising a diaphragm and a coil that is fixed to the diaphragm and faces a magnetic gap that is a gap between the yoke and the top plate, the yoke has a concave section in the short axis direction, and a long axis. A cross section in the direction is a flat plate shape, and a first magnet and a first top plate are fixed on the magnet at a central portion of the yoke, and a gap is separated from the first magnet of the yoke in the longitudinal direction. And a second top plate is fixed on the magnet, and the first magnet and the second magnet are magnetized in directions perpendicular to each other, and the yoke A first magnetic circuit passing through the first magnet and the first top plate and a second magnetic circuit passing through the yoke, the second magnet and the second top plate are formed. Therefore, by utilizing the space outside the major axis side of the speaker having a substantially rectangular or oval planar shape, a coil and a top plate are disposed there and a magnetic circuit is installed. Magnetic force necessary for driving can be ensured. Compared with products having the same magnetic force, the thickness can be reduced while maintaining the characteristics. In addition, the output can be increased as compared with a conventional product having the same thickness.

  Further, by providing a through hole in the first top plate, the first magnet, and the yoke inside the coil or the yoke under the coil, the flow of air below the diaphragm is made smooth, and the vibration The suppression of the amplitude of the plate can be reduced.

  Further, by making the yoke and the frame an integral part, it is possible to eliminate the bonding process of two parts, reduce the number of parts, and improve the precision of parts.

  Hereinafter, the micro speaker of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a main part of a micro speaker according to a first embodiment of the present invention, FIG. 2 is a central longitudinal sectional view showing a cross section in the minor axis X direction of FIG. 1, and FIG. It is a center longitudinal cross-sectional view which shows a Y direction cross section.

  First, the configuration of the micro speaker according to the first embodiment of the present invention will be described. 1 to 3, the microspeaker 1 has a slim shape whose planar shape is substantially rectangular, the yoke 2 is a generally rectangular shape made of SPCC, permalloy, or the like, and the short-axis X-direction cross section is a concave shape. Yes, the cross section in the long axis Y direction is flat. A substantially rectangular parallelepiped first magnet 3 made of neodymium sintered magnet or the like is fixed to the central portion of the yoke 2, and a substantially rectangular parallelepiped first top plate 5 made of SPCC or permalloy or the like is placed on the magnet 3. It is fixed.

  A substantially rectangular parallelepiped second magnet 4 made of a neodymium sintered magnet or the like is fixed on the yoke 2 outside the Y axis direction of the magnet 3 with a gap g therebetween. A substantially rectangular parallelepiped second top plate 6 made of SPCC, permalloy or the like is fixed on the magnet 4. The magnet 3 and the magnet 4 are magnetized in the opposite vertical direction, and the inner magnetic type magnetic circuit 9 passing through the yoke 2 and the magnet 3 and the top plate 5 in the cross section in the long axis Y direction is the yoke in the cross section in the short axis X direction. 2, a magnetic circuit 10 passing through the magnet 4, the top plate 6 and the top plate 5 is formed.

  The yoke 2 is combined with the magnets 3 and 4 and the top plates 5 and 6 to form a magnetic circuit unit, and the outer periphery of the yoke 2 is fixed to a frame 8 made of plastic resin such as LCP, PPA or ABS. . The yoke 2 can be integrated with the frame 8 by insert molding. Further, the frame and the yoke can be integrally formed of the same material. FIG. 4 is a perspective view showing an embodiment in which a frame and a yoke are integrally formed. A rectangular annular coil 7 made of a wire such as a copper wire or an aluminum wire is fixed to a vibration plate (not shown) made of a plastic film such as PET or PEN, and faces a gap g which is a magnetic gap.

  Next, the operation of the first exemplary embodiment of the present invention will be described. When an audio signal is input to the coil 7 of the micro speaker 1, the magnetic field excited by the coil 7 reacts with the magnetic field formed by the magnetic circuits 9 and 10, and is joined to the coil 7 together with the coil 7. The diaphragm vibrates up and down and emits sound.

  Next, effects of the first exemplary embodiment of the present invention will be described. A magnetic circuit 9 is formed in the short axis direction of the microspeaker 1 having a substantially rectangular planar shape, and a magnetic circuit 10 is formed in the long axis direction, thereby ensuring a magnetic force necessary for driving the coil 7. can do. The characteristic of the speaker is determined by the strength of the magnet. When the magnet type is the same, the strength of the magnet is determined by the volume (thickness). Accordingly, when compared with a product that is an internal magnetic circuit having the same magnetic force on both the short axis side and the long axis side, the volume of the magnet can be increased by the second magnet 4 further added to the outside of the long axis. Even so, an equivalent volume can be secured. That is, the speaker can be thinned while maintaining the same characteristics. Further, when compared with a conventional product having the same thickness, the output can be increased. Furthermore, by integrating the yoke 2 and the frame 8, it is possible to eliminate the bonding process of two parts, reduce the number of parts, and improve the precision of the parts.

  Next, a micro speaker according to a second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 5 is a perspective view showing a main part in which a diaphragm and a protector of a micro speaker according to a second embodiment of the present invention are omitted.

  Open holes 5 a, 3 a and 2 a are formed in the center of the top plate 5, the magnet 3 and the yoke 2 of the micro speaker 11. Since other configurations are the same as those of the micro speaker 1 according to the first embodiment, the same components are denoted by the same names and reference numerals, and detailed description thereof is omitted.

  Next, effects of the second exemplary embodiment of the present invention will be described. By providing open holes 5a, 3a and 2a which are through holes in the top plate 5, magnet 3 and yoke 2 inside the coil 7, the flow of air under the diaphragm is smoothed, and the suppression of the amplitude of the diaphragm is reduced. can do. Also, the same effect can be obtained by providing a through hole in the yoke 2 under the coil 7.

  In the microspeaker according to the embodiment described above, the planar shape is substantially rectangular. However, the present invention can be similarly applied to a rim type whose planar shape is approximately oval or approximately elliptical. Further, the shape of the magnet is not necessarily limited to a substantially rectangular parallelepiped shape.

It is a perspective view which shows the principal part of the microspeaker which is the 1st Embodiment of this invention. It is a center longitudinal cross-sectional view which shows the short-axis X direction cross section of the micro speaker of FIG. It is a center longitudinal cross-sectional view which shows the long-axis Y direction cross section of the micro speaker of FIG. It is a perspective view which shows one Embodiment of the yoke integrally formed with the flame | frame. It is a perspective view which shows the principal part of the microspeaker which is the 2nd Embodiment of this invention.

Explanation of symbols

1, 11 Micro speaker 2, 12 Yoke 3, 4 Magnet 5, 6 Top plate 7 Coil 8 Frame g Gap

Claims (4)

  A microspeaker having a substantially rectangular shape, a substantially oval shape, or a substantially elliptical shape in plan view, a frame in which a magnetic circuit unit combining a yoke, a magnet, and a top plate is fixed; a diaphragm fixed to the frame; and In a micro speaker comprising a coil fixed to a diaphragm and facing a magnetic gap that is a gap between the yoke and the top plate, the yoke has a concave section in the short axis direction and a flat section in the long axis direction. A first magnet and a first top plate are fixed on the magnet at a central portion of the yoke, and the second magnet is separated from the first magnet of the yoke by a gap in the longitudinal direction. A second top plate is fixed on the magnet, and the first magnet and the second magnet are magnetized in directions opposite to each other, the yoke and the first magnet. Fine said first first magnetic circuit and said yoke through the top plate, the second micro-speaker, wherein the second magnetic circuit is formed through the magnet and the second top plate.   2. The microspeaker according to claim 1, wherein an open hole penetrating the first top plate, the first magnet, and the yoke is formed.   The micro speaker according to claim 1, wherein a through hole is provided in the yoke under the coil.   The micro speaker according to any one of claims 1 to 3, wherein the yoke and the frame are integrally formed.

Images