JP2008252721A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker which enables a light emitting element to emit light with ample brightness, even if only a little current flows to a voice coil and which can be achieved, using a simple configuration. <P>SOLUTION: The speaker 1 is of inner magnet type and comprises a magnetic circuit 2, bobbin 3, first voice coil 4, frame 5, edge 6, diaphragm 7, damper 8, power generating coil 9, light-emitting element 10, and auxiliary magnet 11. At least part of the auxiliary magnet 11 is arranged inside the power generating coil 9, to increase an AC magnetic flux penetrating the inside the power generating coil 9 for the AC magnetic flux that penetrates inside the power generating coil 9 to be increased, and the light-emitting intensity of the light-emitting element 10 can be increased, without having to increase an AC current flowing to the first voice coil 4. Accordingly, there is also no risk of increase in power consumption. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a speaker with illumination that can vary the light emission intensity in accordance with the intensity of an input signal.

  For the purpose of monitoring the input to the speaker, a speaker in which a light emitting element such as a light emitting diode is arranged at a position where light emission can be visually recognized has been proposed. In this type of speaker, an induced electromotive force is generated using an alternating current flowing in the voice coil, and a light emitting element is caused to emit light using the induced electromotive force (see Patent Document 1).

For example, in Patent Document 1, as shown in FIG. 8, a diaphragm member (111) having a cylindrical portion (124) protruding rearward from a central portion on the rear surface side and a cylindrical portion (124) are fitted. A predetermined magnetic field is generated in a spatial range including the voice coil (125) that is displaced in the axial direction of the diaphragm member (111) and supplied with a drive current integrally with the diaphragm member (111), and the voice coil (125). Magnetic field generating device (115, 118, 119), a power generating coil (132) that generates an induced electromotive force due to a variable driving current flowing in the voice coil (125), and a voice coil (125) from the front side of the voice coil (125) 125) is disclosed that includes light-emitting elements (133a, 133b) that are arranged so that light emission can be visually recognized in the region 125) and that emit light by power from the power generation coil (132). . In the speaker 100, the power generating coil (132) is disposed on the inner peripheral side of the cylindrical portion (124), and the disc-shaped magnetic body (120) is disposed on the inner peripheral side of the power generating coil (132).
Japanese Patent No. 3542516

  However, the speaker of Patent Document 1 has the following problems. In the magnetic circuit 101 shown in FIG. 8, the disk-shaped magnetic body (120) is disposed on the inner peripheral side of the power generation coil (132) for the purpose of increasing the magnetic flux density. Has a large magnetic resistance, and the required magnetic flux density cannot be obtained, so that the electromotive force generated by the power generating coil (132) is small. For this reason, the light emitting elements (133a, 133b) have a problem that the light emission intensity with sufficient brightness cannot be obtained.

  The present invention has been made in view of such problems, and an object of the present invention is to make it possible to cause a light emitting element to emit light with sufficient brightness even when a current flowing through a voice coil is small. An object of the present invention is to provide a speaker that can be realized with a structure.

  According to one aspect of the present invention, a magnetic circuit, a bobbin disposed so as to surround at least a part of the magnetic circuit, and wound around the bobbin and disposed in a magnetic gap of the magnetic circuit, A first voice coil that can vibrate; a frame joined to the magnetic circuit; a diaphragm having a central rear portion joined to the bobbin and an outer peripheral edge supported by the frame via an edge; The inner periphery is joined to the bobbin, the outer periphery is supported by the inner periphery of the frame, and the electromotive force is generated by the alternating current that flows inside the bobbin and is disposed inside the bobbin. A power generating coil that is disposed inside the bobbin, forms a closed circuit with the power generating coil, and performs a blinking operation by an induced electromotive force of the power generating coil, and at least Some are arranged inside the power generating coil, a speaker, characterized in that it comprises an auxiliary magnet to increase the alternating current magnetic flux penetrating the inside of the power generation coil is provided.

  ADVANTAGE OF THE INVENTION According to this invention, even if there is little electric current which flows into a voice coil, a light emitting element can be light-emitted with sufficient brightness, and the speaker which can be implement | achieved by a simple structure can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view of a speaker according to a first embodiment of the present invention. A speaker 1 in FIG. 1 is an internal magnet type, and includes a magnetic circuit 2, a bobbin 3, a first voice coil 4, a frame 5, an edge 6, a diaphragm 7, a damper 8, and a power generation coil. 9, a light emitting element 10, and an auxiliary magnet 11.

  The magnetic circuit 2 includes a columnar main magnet 12, an annular pole piece 13 disposed on the front surface of the main magnet 12, an annular under plate 14 disposed on the rear surface of the main magnet 12, and the under plate 14. And a bowl-shaped pot yoke 15 disposed on the rear surface.

  The bobbin 3 is disposed so as to surround at least a part of the magnetic circuit 2. The first voice coil 4 is wound around the bobbin 3 and is disposed in the magnetic gap of the magnetic circuit 2 so that it can vibrate back and forth. The frame 5 is joined to the magnetic circuit 2. More specifically, the rear end of the frame 5 is joined to the front end of the pot yoke 15, and the edge 6 is joined to the front end of the frame 5. A gasket 16 is joined to the front surface of the outer peripheral sticking portion of the edge 6. A tinsel wire (not shown) drawn from the first voice coil 4 is connected to the terminal plate 17.

  The diaphragm 7 has a central rear part joined to the bobbin 3, and an outer peripheral edge part supported by the frame 5 via an edge 6. The damper 8 has an inner peripheral portion joined to the bobbin 3 and an outer peripheral portion supported by the inner peripheral portion of the frame 5.

  The power generation coil 9 is disposed inside the bobbin 3 and generates an induced electromotive force by an alternating current flowing through the first voice coil 4. The light emitting element 10 is arranged inside the bobbin 3 so that the emitted light can be visually recognized from the outside, forms a closed circuit together with the power generating coil 9, and performs blinking operation by the induced electromotive force of the power generating coil 9.

  The auxiliary magnet 11 is at least partially disposed inside the power generation coil 9 and is provided to increase the AC magnetic flux penetrating the power generation coil 9. The auxiliary magnet 11 is a permanent magnet, and more specifically, is formed of a rare earth magnet such as a neodymium magnet or a samacoba (samarium cobalt) magnet.

  The power generation coil 9 is wound around the outer surface of the auxiliary magnet 11, and the direction of the magnetic force generated by the auxiliary magnet 11 is the same as or opposite to the direction of the magnetic force generated by the power generation coil 9.

  FIG. 2 is an electric circuit diagram of the speaker 1 of FIG. As shown in the figure, the first voice coil 4 and the power generating coil 9 constitute a transformer 19 that is magnetically coupled. The primary side of the transformer 19 is provided with a primary closed circuit in which a first voice coil 4 and a drive source 18 for passing an alternating current through the first voice coil 4 are connected in series. On the secondary side of the transformer 19, a secondary closed circuit in which the power generation circuit and the light emitting element 10 are connected in series is provided. Although not shown in FIG. 1, the drive source 18 is composed of, for example, an amplifier for driving the speaker 1.

  When an alternating current flows through the first voice coil 4 in response to power supply from the drive source 18, an induced electromotive force is generated in the power generation coil 9 magnetically coupled to the first voice coil 4. The induced electromotive force is generated in a direction that prevents the change of the alternating magnetic flux penetrating the inside of the power generation coil 9. Since the current flowing through the first voice coil 4 changes continuously with time, the induced electromotive force generated in the power generation coil 9 also changes continuously. As a result, the current flowing through the secondary closed circuit becomes , Become alternating current.

  As shown in FIG. 2, the light emitting element 10 has a rectifying action like a diode, and therefore emits light only when a current flows in a predetermined direction through the secondary side closed circuit. That is, the light emitting element 10 performs a blinking operation at the same frequency as the frequency of the alternating current flowing through the first voice coil 4.

  As described above, the direction of the magnetic force of the auxiliary magnet 11 and the direction of the magnetic force generated by the power generation coil 9 may be the same or opposite depending on the polarity of the induced electromotive force of the power generation coil 9. Therefore, when they are in the same direction, the magnetic forces strengthen each other, and when they are in the opposite direction, the magnetic forces weaken each other. Thereby, the AC magnetic flux (flux change amount) penetrating through the power generation coil 9 becomes larger than that in the case where the auxiliary magnet 11 is not provided.

Here, the induced electromotive force e of the power generation coil 9 is expressed by the following equation (1), where N is the number of turns of the power generation coil 9 and Φ is the magnetic flux penetrating the power generation coil 9.

  The second term dΦ / dt on the right side of the equation (1) is the AC magnetic flux. As can be seen from the equation (1), if the number N of windings is constant, the induced electromotive force e increases as the AC magnetic flux increases. Therefore, as shown in FIG. 1, by providing the auxiliary magnet 11, the alternating magnetic flux increases, thereby the induced electromotive force e also increases and the alternating current flowing in the secondary closed circuit increases. When the alternating current flowing through the secondary closed circuit increases, the light emitting element 10 emits light more strongly. Actually, since the light emitting element 10 emits light only during a half cycle of the alternating current, by providing the auxiliary magnet 11, the light emitting element 10 performs a blinking operation with a stronger light emission intensity.

  The inventor has the case where the auxiliary magnet 11 is omitted from the structure of FIG. 1, the case where a magnetic body is provided instead of the auxiliary magnet 11 as in the conventional example shown in FIG. 6, and the case of the structure of FIG. The magnetic flux density inside the magnetic circuit 2 was measured and the results are summarized in FIG. FIG. 3 shows the result of measuring the magnetic flux density at any three locations (measurement points 1 to 3) on the outer periphery of the pole piece 13 by inserting a Hall element in the magnetic gap of the magnetic circuit 2, and these three locations. The average value of the measurement results is described.

  As can be seen from FIG. 3, the magnetic flux density inside the magnetic circuit 2 in this embodiment is about 1.8 times that of the case where the power generating coil 9 is omitted, and the inner peripheral side of the power generating coil 9 is made of a magnetic material. The result increased by about 1.4 times compared with the case.

  The power generation coil 9 in FIG. 1 does not require a drive source, and a structure in which the power generation coil 9 is wound around an auxiliary magnet 11 made of a permanent magnet is prepared in advance, and this structure is mounted on the magnetic circuit 2. Therefore, the speaker 1 can be easily assembled without the need for wiring.

  As described above, in the first embodiment, since the auxiliary magnet 11 is arranged inside the power generation coil 9, the alternating magnetic flux penetrating the inside of the power generation coil 9 can be increased, and the first voice coil 4. The light emission intensity of the light emitting element 10 can be increased without increasing the alternating current flowing through the light source. Therefore, there is no risk of increasing power consumption.

  Further, since the auxiliary magnet 11 is disposed inside the power generation coil 9, the size of the speaker 1 does not change depending on the presence or absence of the auxiliary magnet 11.

(Second Embodiment)
The second embodiment is characterized in that the structure of the voice coil is different from that of the first embodiment.

  FIG. 4 is a cross-sectional view of the speaker 1a according to the second embodiment of the present invention, and FIG. 5 is an electric circuit diagram of the speaker 1a of FIG. 4 and 5, the same reference numerals are given to the same components as those in FIGS. 1 and 2, and the following description will focus on the differences.

  The speaker 1 a in FIG. 4 includes a second voice coil 20 in addition to the first voice coil 4. The first voice coil 4 is wound around the rear end side of the bobbin 3 and arranged in the magnetic gap of the magnetic circuit 2 as in FIG. The second voice coil 20 is wound around the front end side of the bobbin 3. As shown in FIG. 5, the first and second voice coils 4 and 20 are connected in series with each other.

  The speaker 1a in FIG. 5 has the same structure as that in FIG. 1 except for the first and second voice coils 4 and 20, and the auxiliary magnet 12 is wound around the auxiliary magnet 11 and placed on the front surface of the magnetic circuit 2. Has been placed.

  As shown in FIG. 5, the first and second voice coils 4, 20 and the power generation coil 9 constitute a magnetically coupled transformer. The first and second voice coils 4 and 20 and the drive source 18 for supplying an alternating current to these voice coils constitute a primary closed circuit. The power generation coil 9 and the light emitting element 10 constitute a secondary closed circuit.

  FIG. 6 is a diagram showing the magnetic path of the magnetic field line Φ1 formed by the first voice coil 4 and the magnetic path of the magnetic field line Φ2 formed by the second voice coil 20. As illustrated, the two magnetic force lines Φ1 and Φ2 penetrate the inside of the power generation coil 9 in the same direction. Thereby, the AC magnetic flux penetrating the inside of the power generation coil 9 is increased and the induced electromotive force of the power generation coil 9 is increased as compared with the case of only the first voice coil 4, and as a result, the light emission of the light emitting element 10 The strength can be further increased.

  FIG. 7 shows a case where only the first voice coil 4 is provided as in the first embodiment, and a case where the first and second voice coils 4 and 20 are provided and connected in series as in the present embodiment. It is the figure which compared the induced electromotive force produced | generated by the electric power generation coil 9 about. In FIG. 7, the induced electromotive force is measured by changing the frequency of the alternating current flowing through the first voice coil 4 in various ways.

  As can be seen from FIG. 7, the induced electromotive force in the present embodiment increases to about 1.4 times the induced electromotive force in the first embodiment regardless of the frequency of the alternating current. Further, the induced electromotive force increases as the frequency of the alternating current increases. This tendency is the same in the case of the first embodiment.

  Thus, in the second embodiment, since the second voice coil 20 is newly provided, the AC magnetic flux penetrating the inside of the power generation coil 9 can be further increased, and the induced electromotive force of the power generation coil 9 is further increased. Thus, the light emission intensity of the light emitting element 10 can be further increased.

  In the second embodiment, the first voice coil 4 is wound around the rear end side of the bobbin 3 and the second voice coil 20 is wound around the front end side. The winding position of 20 does not necessarily need to be the end of the bobbin 3, and the specific winding position is not limited as long as the first and second voice coils 4 and 20 are arranged in the front and rear.

  In each embodiment described above, an example in which only one light emitting element 10 is provided has been described, but the number of light emitting elements 10 is not particularly limited. Further, the type of the light emitting element 10 is not particularly limited. For example, various light emitting elements 10 such as a light emitting diode and a semiconductor laser are applicable.

  In each of the above-described embodiments, the representative embodiment of the present invention has been described. However, the present invention is not limited to the structure of the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. Is possible.

  For example, in each of the above-described embodiments, the inner magnetic type magnetic circuit 2 has been described, but an outer magnetic type may be used. Further, the shape of the diaphragm 7 is not limited to the cone shape, and various shapes such as a dome shape are applicable.

1 is a cross-sectional view of a speaker according to a first embodiment of the present invention. The electric circuit diagram of the speaker 1 of FIG. The case where the auxiliary magnet 11 is omitted from the structure of FIG. 1, the case where a magnetic material is provided instead of the auxiliary magnet 11 as in the conventional example shown in FIG. 6, and the case of the structure of FIG. The figure which measured the magnetic flux density of and summarized the result. Sectional drawing of the speaker 1a which concerns on the 2nd Embodiment of this invention. The electric circuit diagram of the speaker 1a of FIG. The figure which shows the magnetic path of the magnetic force line formed of the 1st voice coil 4, and the magnetic path of the magnetic force line formed of the 2nd voice coil 20. Electric power generation in the case where only the first voice coil 4 is provided as in the first embodiment and in the case where the first and second voice coils 4 and 20 are provided and connected in series as in the present embodiment The figure which compared the induced electromotive force produced | generated by the coil 9. FIG. Sectional drawing of the speaker disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Speaker 2 Magnetic circuit 3 Bobbin 4 1st voice coil 5 Frame 6 Edge 7 Diaphragm 8 Damper 9 Electric power generation coil 10 Light emitting element 11 Auxiliary magnet 12 Main magnet 13 Pole piece 14 Under plate 15 Pot yoke 16 Gasket 17 Terminal Plate 18 Drive source 19 Transformer 20 Second voice coil Φ1, Φ2 Magnetic field lines

Claims (6)

A magnetic circuit;
A bobbin disposed to surround at least a portion of the magnetic circuit;
A first voice coil wound around the bobbin and disposed in a magnetic gap of the magnetic circuit and capable of vibrating back and forth;
A frame joined to the magnetic circuit;
A diaphragm in which a central rear portion is joined to the bobbin and an outer peripheral edge portion is supported by the frame via an edge;
A damper whose inner periphery is joined to the bobbin and whose outer periphery is supported by the inner periphery of the frame;
A power generating coil that is arranged inside the bobbin and generates an induced electromotive force by an alternating current flowing in the first voice coil;
A light emitting element that is disposed inside the bobbin, forms a closed circuit together with the power generation coil, and performs a blinking operation by an induced electromotive force of the power generation coil;
An auxiliary magnet that increases at least a part of the alternating current magnetic flux penetrating through the inside of the power generating coil, at least a part of the speaker is disposed inside the power generating coil. The auxiliary magnet is a permanent magnet having magnetic poles in the front-rear direction,
The speaker according to claim 1, wherein the power generation coil is wound around an outer surface of the auxiliary magnet so that an AC magnetic flux penetrates the power generation coil in the front-rear direction.   The speaker according to claim 1, wherein the auxiliary magnet is joined to a front surface of the magnetic circuit.   The speaker according to any one of claims 1 to 3, wherein the light emitting element is disposed on a front surface of the auxiliary magnet so that the light emission is visually recognized from the front of the diaphragm.   5. The device according to claim 1, further comprising: a second voice coil wound around the bobbin on a front side of the first voice coil and connected in series with the first voice coil. The speaker according to 1. The magnetic circuit is an inner magnet type,
The magnetic circuit is:
The main magnet,
A pole piece arranged in front of the main magnet;
An under plate disposed on a rear surface of the main magnet;
A pot yoke disposed on the rear surface of the under plate,
The speaker according to claim 1, wherein the auxiliary magnet is disposed on a front surface of the pole piece.

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