JP2008085985A - Electroacoustic transducer and diaphragm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroacoustic transducer capable of improving a pitch extent from a middle-frequency range to a high-frequency one, and to provide a diaphragm. <P>SOLUTION: The diaphragm 11 comprises a central vibration section 19 in a dome-like section, and a periphery vibration section 21 that is arranged at the periphery of the central vibration section 19 integrally and continuously, and has an edge section 21b fixed to a frame 13 for support and has a dome-like section. The diaphragm 11 is formed in a combined shape of a thick board thickness region D and a thinner board thickness region D-1 than the thick one D. The thin board thickness region D-1 is set to be the edge section 21b of the periphery vibration section 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an all-band electroacoustic transducer suitable for a headphone or the like and a diaphragm.

  There is a full-band electroacoustic transducer for reproducing sound over a wide band from a low sound range to a high sound range.

  The outline of the electroacoustic transducer has a diaphragm and a magnetic circuit unit for driving the diaphragm. For example, a diaphragm 111 housed in a frame 113 is used as the diaphragm as shown in FIG. . The diaphragm 111 has a structure that covers the entire range from the low range to the high range by combining the dome-shaped central vibrating portion 101 and the outer peripheral vibrating portion 103 that is continuously arranged integrally with the outer periphery of the central vibrating portion 101. It has become. A general frequency response (output sound pressure frequency characteristic) at this time is shown in FIG.

  The frequency response shown in FIG. 5 is obtained by automatically measuring the sound pressure level at a point of 1 m on the reference axis so as to form a continuous curve corresponding to the frequency. In this frequency response, the reproduced frequency range is referred to as an effective frequency band FB. The frequency of the low frequency reproduction limit L and the high frequency reproduction limit H in which the output sound pressure level is decreased by -10 dB in the range of the low frequency resonance frequency fo indicating the low frequency limit and the high frequency resonance frequency fh indicating the high frequency limit. A range is shown. The characteristic is divided into two parts: a flat characteristic of the piston vibration region PB and a divided vibration region DB composed of a complicated vibration region of the diaphragm. In the whole area type, the entire effective frequency band FB from the low frequency reproduction limit L to the high frequency reproduction limit H is used.

  In this case, the frequency characteristic of the output sound pressure is substantially flat because of the piston vibration area PB that vibrates with the edge portion 105 as a fulcrum in the low sound range. In the middle sound range, the edge portion 105 around the diaphragm and the connecting portion at the boundary between the central vibration portion 101 and the outer peripheral vibration portion 103 are affected, and due to resonance, the opposite phases as shown by arrows a and b in FIG. Vibrations cancel each other out and a dip called a mid-sound valley d occurs. In the high sound range, the diaphragm cannot perform piston vibration and becomes a divided vibration area DB in which each part of the diaphragm vibrates in a complicated manner, so that a lot of peak dip occurs. At the high frequency limit, high frequency resonance occurs mainly at the frequency determined by the stiffness and mass of the central part of the diaphragm and the mass of the voice coil 107, and the peak at this high frequency limit frequency (high frequency reproduction limit H) is the last. Sound pressure drops rapidly.

As a means for solving these problems, for example, a diaphragm material having an acoustic loss characteristic of 0.02 or more can be used to expand a high sound range, and a frequency band of 20 kHz or more can be reproduced using the divided vibration of the diaphragm. Means for doing this are known. Alternatively, there is known a means for reducing the dip by suppressing the antiphase vibration of the edge portion in the middle range by using an elastic member for fixing and supporting the edge portion.
JP 2002-152885 A JP-A-2005-204215

  As described above, in the all-band type diaphragm, a problem particularly occurs from the middle sound range to the high sound range. However, in the method of Patent Document 1 for improving the mid-range, it is necessary to use a special material having an acoustic loss characteristic of 0.02 or more, and there are problems that do not lead to great improvement in the range other than the high range. .

  On the other hand, in the means of Patent Document 2 in which the edge portion is supported by the elastic member, the vibration characteristic of the edge portion can be improved, but it does not lead to the improvement of the reverse phase occurring at the boundary between the central vibration portion and the outer peripheral vibration portion. , Have a problem from mid to high range.

  Accordingly, an object of the present invention is to provide an electroacoustic transducer and a diaphragm capable of improving the sound quality in the sound range from the middle sound range to the high sound range.

  In order to achieve the above object, according to the present invention, a magnetic circuit, a frame for housing the magnetic circuit, a central vibrating portion having a substantially dome-shaped cross section, and a cross section formed over the entire outer periphery of the central vibrating portion. Includes a diaphragm having a substantially dome-shaped outer peripheral vibration part, an end of an edge portion on the outer peripheral side of the outer peripheral vibration part fixed to the frame, and the diaphragm includes the entire central vibration part It is an electroacoustic transducer formed by forming a thick region and a second plate thickness region that includes the edge portion of the outer peripheral vibration portion and whose plate thickness is thinner than the first plate thickness region.

  Further, according to the present invention, the magnetic circuit, the frame for housing the magnetic circuit, the central vibrating portion having a substantially dome-shaped cross section, and the outer peripheral vibration having a substantially dome-shaped cross section formed over the entire outer periphery of the central vibrating portion. And an end of the edge portion on the outer peripheral side of the outer peripheral vibration portion is fixed to the frame, and the vibration plate is connected to the entire central vibration portion and the connection portion with the central vibration portion in the outer peripheral vibration portion. An electroacoustic formed by forming a first plate thickness region including a predetermined predetermined region and a second plate thickness region which is a portion other than the predetermined region in the outer peripheral vibration portion and whose plate thickness is thinner than the first plate thickness region. It is a converter.

  Further, according to the present invention, the magnetic circuit, the frame for housing the magnetic circuit, the central vibrating portion having a substantially dome-shaped cross section, and the outer peripheral vibration having a substantially dome-shaped cross section formed over the entire outer periphery of the central vibrating portion. And a diaphragm in which an end of an edge portion on the outer peripheral side of the outer peripheral vibration part is fixed to the frame, and the vibration plate includes a first region including the entire central vibration part, and an edge of the outer peripheral vibration part An electroacoustic transducer comprising a second region that includes a portion and is softer than the first region and has flexibility.

  Further, in the present invention, a diaphragm including a central oscillating portion having a substantially dome-shaped cross section and an outer peripheral vibrating portion having a substantially dome-shaped cross section formed over the entire outer periphery of the central vibrating portion, It is a diaphragm formed by forming a first plate thickness region including the entire central vibration portion and a second plate thickness region including the edge portion of the outer peripheral vibration portion and having a plate thickness thinner than the first plate thickness region. It is characterized by that.

  Furthermore, in the present invention, a diaphragm comprising a central oscillating portion having a substantially dome-shaped cross section and an outer peripheral vibrating portion having a substantially dome-shaped cross section formed over the entire outer periphery of the central vibrating portion, The first plate thickness region including a predetermined region connected to the whole vibration portion and the connection portion of the outer peripheral vibration portion with the central vibration portion, and a portion other than the predetermined region in the outer peripheral vibration portion, and the plate thickness is the first plate thickness It is a diaphragm formed by forming a second plate thickness region thinner than the region.

  Furthermore, in the present invention, a diaphragm comprising a central oscillating portion having a substantially dome-shaped cross section and an outer peripheral vibrating portion having a substantially dome-shaped cross section formed over the entire outer periphery of the central vibrating portion, The diaphragm is formed by forming a first region including the entire central vibration portion and a second region including the edge portion of the outer peripheral vibration portion and softer than the first region and having flexibility. It is characterized by.

  According to the present invention, the diaphragm becomes a piston vibration region that vibrates integrally with the edge portion of the outer peripheral vibration portion as a fulcrum, and the frequency characteristic of the output sound pressure can be made flat.

  In particular, in the mid-range, the edge portion, the central vibration portion, and the portion that connects the outer peripheral vibration portion are designed to improve the sound pressure dip by suppressing the vibrations in the opposite phase due to resonance by the plate thickness or the hard plate thickness that are integrally continuous. be able to. In addition, in a high sound range, a complicated divided vibration of the diaphragm can be suppressed by a thick plate thickness or a hard plate thickness, and the peak dip can be improved.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and this technical idea specifies the structure, arrangement, etc. of constituent articles as follows. Not what you want.

  As shown in FIG. 1, an electroacoustic transducer 1 according to an embodiment is arranged above a magnetic circuit 9 including a magnetic pole (yoke) 3, a central pole 5, and a magnet 7, and the magnetic circuit 9. And a diaphragm 11.

  The magnetic pole 3, the central pole 5, and the magnet 7 constituting the magnetic circuit 9 are fitted with a columnar protrusion 17 rising from the recess 15 of the frame 13, and a predetermined gap G is provided between the magnetic pole 3 and the central pole 5. It is accommodated in the recess 15.

  The diaphragm 11 includes a central vibrating portion 19 having a dome-shaped cross section and an outer peripheral vibrating portion 21 formed integrally and continuously on the outer periphery of the central vibrating portion 19, and from the central vibrating portion 19 to the outer peripheral vibrating portion 21. The voice coil 22 is dropped into the gap G on the back surface of the boundary T that continues to, and is joined and supported via an adhesive while being centered. On the other hand, the outer peripheral vibration portion 21 includes a plate thickness portion 21a having the same plate thickness as that of the central vibration portion 19 and an edge portion 21b having a plate thickness thinner than that. The peripheral edge P of the edge portion 21b has a support structure bonded to the outer peripheral edge of the frame 13 by an adhesive means such as an adhesive.

  As shown in FIG. 1, the region (second plate thickness region) D-1 of the edge portion 21b of the outer peripheral vibration portion 21 is a region (first first region) composed of the central vibration portion 19 and the plate thickness portion 21a of the outer peripheral vibration portion 21. Plate thickness region) The plate thickness is formed to be thinner than the plate thickness α of D, and a piston vibration region is generated that vibrates using the region D-1 of the edge portion 21b as a fulcrum, and the sound pressure dip as a valley is kept small. β is set.

  Although the plate thickness dimension α is not particularly limited, for example, when used for a headphone or an earphone, it can be set to, for example, about 5 μm to 250 μm in consideration of necessary weight, stiffness, and the like.

  In addition, the first plate thickness region D composed of the central vibration portion 19 excluding the edge portion 21 b and the plate thickness portion 21 a of the outer peripheral vibration portion 21 has a central vibration portion at a boundary T that extends from the central vibration portion 19 to the outer peripheral vibration portion 21. The plate thickness dimension β is set such that the vibrations in the opposite phases in which the sounds of 19 and the outer peripheral vibration part 21 cancel each other are suppressed to be small.

  The plate thickness dimension β is not particularly limited. For example, when used for a headphone or an earphone, it can be set to, for example, about 4 μm to 40 μm from the viewpoint of weight management and stiffness.

  The diaphragm 11 in FIG. 1 has a single layer structure made of, for example, a synthetic resin film. As the synthetic resin film, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetherimide (PEI), polyimide (PI) and the like are preferably used. In addition, non-woven fabrics such as vinylon fibers made of a mixture of artificial materials and natural materials, paper making made of natural materials such as Ganpi paper and mulberry paper, and wooden sheets can be used.

  As shown in FIG. 2A and FIG. 2B, the diaphragm 11 is formed by thinly forming a central vibration part 19 and an outer peripheral vibration part 21 on the outer periphery thereof, and a wooden sheet 23 is overlapped thereon. A laminated structure may be used.

  The wooden sheet 23 is made, for example, by rotating a log-like wood against a cutting blade and rotating the slice, so-called wiggle. It can also be produced by slicing from plate material or wood.

  Examples of the natural wood material used include materials that are easy to form in addition to conditions such as uniform and small conduit density, short conduits, long wood fiber, and slow summer growth. In addition, each condition of acoustic characteristics, for example, that the speed of propagation of sound velocity is high, and that it has moderately high internal loss, it is optimal to satisfy anisotropy and non-uniformity as well as low density and high elastic modulus. In particular, a birch material such as a birch that grows in a cold area or a high altitude area, which is a broad-leaved tree, can be used. Maple materials such as a maple material such as a cypress material or itayaka maple, or hard maple, and the like can also be used.

  In the diaphragm 11 shown in FIG. 2, it is difficult to realize each condition necessary for achieving predetermined acoustic characteristics using only natural wood. In consideration of the formability and shape stability of the diaphragm 11, in the example shown in FIGS. 2A and 2B, a paper sheet (reinforcing sheet) similar to a wood material and a wooden sheet 23 are overlapped. This is achieved by using a laminated structure.

  The paper sheet is a means using paper making such as Gumpi and Kozo, which has high heat resistance and high mechanical strength such as pulling, and can be impregnated with a resin to increase the mechanical strength. The overlapping direction of the wooden material and the paper material may be such that each fiber direction is parallel or orthogonal, and further random.

  In addition to wooden materials and paper materials, ceramics such as metal oxides, metal nitrides, metal carbides, etc., thin films of simple metals, or two or more alloys are used as the vibration plate in the first plate thickness region D. be able to. In the case of a high-density material, it is preferable to use a thin film or reduce the diaphragm area in order to reduce the weight.

  In FIG. 2, the second plate thickness region D-1 has a single layer structure made of a synthetic resin film. As the material, polyethylene terephthalate, polyethylene naphthalate, polyetherimide, polyimide, or the like is used, and the thickness is set to a thickness β that becomes a piston vibration region in which the entire vibration plate 11 vibrates integrally. Note that the second plate thickness region D-1 can be a laminate of a synthetic resin alone, a wooden material, a paper material, a ceramic material, a metal, and an alloy material.

  According to the electroacoustic transducer 1 configured as described above, the diaphragm 11 including the central vibration portion 19 and the outer peripheral vibration portion 21 on the outer periphery thereof is antiphased by an edge portion 21b made of a thin plate, particularly in the middle sound range. Therefore, the sound pressure dip d can be improved. In addition, it is possible to improve the peak dip by suppressing the complicated divided vibration of the diaphragm by the thick plate thickness in the high sound range.

  The diaphragm 11 in FIGS. 1 and 2 (a) and 2 (b) is an embodiment in which an integrated structure or a laminated structure is used to form the thick plate thickness region D and the thin plate thickness region D-1. However, the shape shown in FIG. That is, in the example shown in FIG. 3, the central vibration portion 19 and the outer peripheral vibration portion 21 are formed on the outer periphery thereof in the same manner as in the embodiment, but the thickness corresponding to the first plate thickness region D where the plate thickness is thick is It is made of a material harder than the thin second plate thickness region D-1. On the other hand, the second plate thickness region D-1, that is, the portion corresponding to the edge portion 21b is formed as an integrally structured diaphragm 11 made of a soft flexible material. In this case, the plate thickness of the first plate thickness region D is equal to the plate thickness of the second plate thickness region D-1, or may be made thinner than the plate thickness of the second plate thickness region D-1. Is possible.

  As the “hard material”, for example, the above-mentioned paper, wood and the like can be used. Similarly, as the “soft flexible material”, paper and wood can be used, and further, synthetic resins of polyethylene terephthalate, polyethylene naphthalate, polyetherimide, and polyimide can be used.

  In addition, after the diaphragm shown in FIG. 3 is molded, a cylindrical hard material block corresponding to the plate pressure region D and a soft material block in contact with the outer periphery thereof are joined in advance, A sheet is sliced into thin layers in the cross-sectional direction. It can be manufactured by molding this sheet and removing an unnecessary outer peripheral portion. In addition, from a single material paper or wood sheet, the portion that becomes the plate pressure region D is impregnated with a thermosetting resin solution such as a phenol resin, and the central portion is formed by simultaneously performing heat curing and molding. A hard diaphragm can be manufactured. Thereby, even when the diaphragm 11 of FIG. 3 is used, the same operation and effect as the diaphragm 11 shown in FIGS. 1 and 2A and 2B can be obtained.

  Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operational techniques are possible for those skilled in the art, and in the implementation stage, modifications can be made without departing from the scope of the invention.

  The electroacoustic transducer and the diaphragm of the present invention can be applied to a full-band and small electrodynamic type speaker such as a headphone or an earphone.

1 is a schematic cut-away view of an electroacoustic transducer according to an embodiment of the present invention. FIGS. 2A and 2B are schematic explanatory views showing a first example of a diaphragm according to the embodiment, FIG. 2A is a top view of the diaphragm after molding, and FIG. 2B is a cross-sectional view of the diaphragm after molding. FIG. 6 is a schematic explanatory diagram showing a second example of a diaphragm according to the embodiment. The schematic explanatory drawing which showed the diaphragm of the electroacoustic transducer of a prior art example. Explanatory drawing of a frequency response (output sound pressure frequency characteristic).

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Magnetic pole 5 ... Center pole 7 ... Magnet 9 ... Magnetic circuit 11 ... Diaphragm 13 ... Frame 15 ... Recess 17 ... Columnar protrusion 19 ... Central vibration part 21 ... Outer periphery vibration part 21a ... Plate thickness part 21b ... Edge part 22 ... Voice coil

Claims (10)

A magnetic circuit;
A frame for housing the magnetic circuit;
A central oscillating portion having a substantially dome-shaped cross section, and an outer peripheral oscillating portion having a substantially dome-shaped cross section which is formed over the entire outer periphery of the central oscillating portion, and an end portion of an edge portion on the outer peripheral side of the outer peripheral vibrating portion is A diaphragm fixed to the frame,
The diaphragm includes a first plate thickness region including the entire central vibration portion, and a second plate thickness region including the edge portion of the outer peripheral vibration portion and having a plate thickness smaller than the first plate thickness region. An electroacoustic transducer characterized by being formed. A magnetic circuit;
A frame for housing the magnetic circuit;
A central oscillating portion having a substantially dome-shaped cross section, and an outer peripheral oscillating portion having a substantially dome-shaped cross section which is formed over the entire outer periphery of the central oscillating portion, and an end portion of an edge portion on the outer peripheral side of the outer peripheral vibrating portion is A diaphragm fixed to the frame,
The diaphragm includes a first plate thickness region including a predetermined region connected to the entire central vibration portion and a connection portion of the outer peripheral vibration portion with the central vibration portion, and a portion other than the predetermined region in the outer peripheral vibration portion. An electroacoustic transducer comprising: a second plate thickness region having a plate thickness that is thinner than the first plate thickness region.   The electroacoustic transducer according to claim 1, wherein the diaphragm has a single-layer structure.   The diaphragm includes a laminate in which the first plate thickness region has a multi-layer structure and the second plate thickness region has a layer structure having a number of layers smaller than the number of layers in the first plate thickness region. The electroacoustic transducer according to claim 1, wherein the electroacoustic transducer is provided. A magnetic circuit;
A frame for housing the magnetic circuit;
A central oscillating portion having a substantially dome-shaped cross section, and an outer peripheral oscillating portion having a substantially dome-shaped cross section which is formed over the entire outer periphery of the central oscillating portion, and an end portion of an edge portion on the outer peripheral side of the outer peripheral vibrating portion is A diaphragm fixed to the frame,
The diaphragm forms a first region including the entire central vibration portion and a second region including the edge portion of the outer peripheral vibration portion and softer than the first region and having flexibility. An electroacoustic transducer characterized by comprising: A central vibrating section having a substantially dome-shaped cross section;
A diaphragm comprising an outer peripheral vibration part formed over the entire outer periphery of the central vibration part and having a substantially dome-shaped cross section,
The diaphragm includes a first plate thickness region including the entire central vibration portion, and a second plate thickness region including the edge portion of the outer peripheral vibration portion and having a plate thickness smaller than the first plate thickness region. A diaphragm characterized by being formed. A central vibrating section having a substantially dome-shaped cross section;
A diaphragm comprising an outer peripheral vibration part formed over the entire outer periphery of the central vibration part and having a substantially dome-shaped cross section,
The diaphragm includes a first plate thickness region including a predetermined region connected to the entire central vibration portion and a connection portion of the outer peripheral vibration portion with the central vibration portion, and a portion other than the predetermined region in the outer peripheral vibration portion. A diaphragm comprising: a second plate thickness region having a plate thickness that is thinner than the first plate thickness region.   The diaphragm according to claim 6 or 7, wherein the first plate thickness region and the second plate thickness region have a single layer structure.   The first plate thickness region has a multi-layer structure, and the second plate thickness region has a layer structure having a number of layers smaller than the number of layers of the first plate thickness region. 8. The diaphragm according to 7. A central vibrating section having a substantially dome-shaped cross section;
A diaphragm comprising an outer peripheral vibration part formed over the entire outer periphery of the central vibration part and having a substantially dome-shaped cross section,
The diaphragm forms a first region including the entire central vibration portion and a second region including the edge portion of the outer peripheral vibration portion and softer than the first region and having flexibility. A diaphragm characterized by comprising:

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