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JP2006229932

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DESCRIPTION JP2006229932
PROBLEM TO BE SOLVED: To suppress generation of a standing wave, obtain higher sound
pressure even in a bass region, achieve high efficiency, perform electroacoustic conversion of an
input signal with high efficiency, have a clear reference direction of sound emission, and
circumferentially Provided are a diaphragm and an electroacoustic transducer capable of
obtaining uniform directivity characteristics. A flat surface including an outer portion (14) having
a circular shape having a diameter (D2) or a polygonal shape inscribed in a circle having a
diameter (D2), and an outer portion (14) A projected shape on P0) has a shape rotationally
symmetric about the central axis (O) of one diameter (D2), an inner-shaped portion (13)
projecting to one side with respect to a plane (P0), and an outer portion (14) and the inner shape
(13), and includes a vibrating surface (12) having an inclined surface inclined with respect to the
central axis (O), the vibrating surface (12) having a central axis (O A diaphragm (10) having a
rotationally symmetrical shape about an eccentric axis (O2) decentered with respect to the
central axis (O) in any cross section orthogonal to the), and an electroacoustic transducer using
the diaphragm (10). [Selected figure] Figure 2
Vibrating plate and electroacoustic transducer
[0001]
The present invention relates to a diaphragm and an electroacoustic transducer.
[0002]
An electroacoustic transducer including a diaphragm, a frame for supporting the outer periphery,
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and a drive unit having a magnetic circuit for vibrating the diaphragm in one axial direction to
emit sound is generally referred to as a speaker, and the diaphragm As a cone-shaped one is
often used.
This cone shape is a surface shape of a truncated cone having an inner periphery and an outer
periphery in which an inclined portion inclined with respect to a central axis which is a vibration
direction is cut off a top portion of a rotationally symmetric cone (circular cone) about the central
axis It is generally considered to be. By the way, it is known that in this substantially frustoconical diaphragm, a standing wave is generated in the radial direction over the entire
circumference of the diaphragm, and peaks and dips are easily generated on the frequency-sound
pressure characteristics.
[0003]
Therefore, in order to make it difficult to generate the peaks and dips, it has been proposed that
the frusto-conical shape of the diaphragm has a shape in which the central axis of the inner
periphery is eccentric from the central axis of the outer periphery. In this eccentrically-shaped
diaphragm, the distance from the inner peripheral end to the outer peripheral end in a radial line
passing through the central axis of the inner peripheral is different depending on the position in
the circumferential direction. Therefore, the wavelength of the standing wave generated on the
diaphragm differs depending on the position in the circumferential direction, and peaks and dips
on the frequency-sound pressure characteristic are smoothed.
[0004]
Thus, although this eccentrically-shaped diaphragm can make it difficult to generate peaks and
dips on the frequency-sound pressure characteristics, it is a general-purpose diaphragm whose
outer shape is formed non-eccentrically with respect to the central axis of the inner periphery.
There is a problem that magnetic circuit parts or a frame can not be diverted. Then, the structure
which eliminates this malfunction is described in patent document 1. FIG. This structure is a
structure for attaching the above-described eccentrically-shaped diaphragm to a magnetic circuit
component or a frame whose outer shape is formed concentrically with respect to the central
axis.
[0005]
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On the other hand, an electro-acoustic transducer that radiates sound in all directions with
respect to the center of the diaphragm is provided with a substantially spherical diaphragm and
one drive unit (magnetic circuit unit) that vibrates the diaphragm in the radial direction. Are
known. The electro-acoustic transducer may be referred to as a sphere speaker or a breathing
sphere speaker, and examples thereof include those disclosed in Patent Document 2 and Patent
Document 3. In these documents, as an example of the diaphragm of the electro-acoustic
transducer, one in which a plurality of diaphragms of a predetermined shape formed
substantially in the plane are combined to form a diaphragm having a substantially spherical
shape is described. JP-A-9-284886 JP-A-2000-78686 JP-A-2001-95088
[0006]
By the way, in patent document 1, in order to attach the diaphragm which has the external shape
eccentrically with respect to the center to the frame to which the magnetic circuit was fixed at
the center, the edge connected to the external shape of a diaphragm has a radial direction width.
There are described speakers having different shapes and a shape in which the edges have a
constant width in the radial direction, and a diaphragm attachment member connecting the edge
and the frame has a shape having a different width in the radial direction. However, in the
configuration described above, since the edge and the diaphragm attachment member are not the
diaphragm and do not cause vibration to emit sound, the projection area of the diaphragm
becomes smaller than the size of the outer shape of the frame. However, there is a problem that
it is difficult to obtain high sound pressure in the bass region, and it is difficult to
electroacoustically convert the input signal with high efficiency. Further, since the outer shape of
the diaphragm does not coincide with the center of the magnetic circuit, the sound emission axis
is not orthogonal to the mounting surface of the speaker, and it is difficult to clarify the reference
direction of the sound emission. There is a problem that it is difficult to make the characteristics
uniform in the circumferential direction.
[0007]
Therefore, the problem to be solved by the present invention is to suppress the generation of
standing waves, to obtain higher sound pressure even in the bass range, to perform
electroacoustic conversion of input signals with high efficiency, and to clarify the reference
direction of sound emission. It is an object of the present invention to provide a diaphragm and
an electroacoustic transducer which can obtain uniform directional characteristics in the
circumferential direction.
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[0008]
In order to solve the above-mentioned subject, the present invention has the following
composition of [1]-[6] as a means.
[1] A flat surface including an outer portion (14) having a circular shape having a diameter (D2)
or a polygonal shape inscribed in a circle having the diameter (D2); and the outer portion (14)
The projected shape on (P0) has a rotationally symmetric shape around the central axis (O) of the
one diameter (D2), and an inner-shaped portion (13) projecting on one side with respect to the
plane (P0) A vibrating surface portion (12) connecting the outer portion (14) and the inner shape
(13) portion and having an inclined surface inclined with respect to the central axis (O); ) Is
characterized in that it has a rotationally symmetrical shape about an eccentric axis (O2)
eccentric to the central axis (O) in any cross section (SS) orthogonal to the central axis (O) It is a
diaphragm (10, 10R). [2] A flat surface including an outer portion (14) having a circular shape
having a diameter (D2) or a polygonal shape inscribed in a circle having the diameter (D2), and
the outer portion (14) The projected shape on (P0) has a rotationally symmetric shape around
the central axis (O) of the one diameter (D2), and an inner-shaped portion (13) projecting on one
side with respect to the plane (P0) A vibrating surface portion (12) connecting the outer portion
(14) and the inner shape portion (13) and having an inclined surface inclined with respect to the
central axis (O); ) Has a circumferential line (15) rotationally symmetrical about the eccentric axis
(O2) eccentric to the central axis (O), and the surface on the eccentric shaft side sandwiching the
circumferential line (15) 12a) and the curvature (R) or inclination angle of the surface (12b) on
the outer side is discontinuous at the circumferential line (15) It is a diaphragm (10, 10R)
characterized by the above. [3] The external part (14) has a regular n-gon shape (n: an integer of
4 or more) inscribed in a circle consisting of one diameter (D2), the center (G0) of the regular ngon and each vertex (T1) One each is provided in n triangles (TR1 to TRn) obtained by dividing
the above-mentioned regular n-gon into n by a line segment (T1G to TnG) connecting the
.about.Tn, and each vertex (T1 to Tn) Tn) and n tops (TP1 to TPn) where a line segment
connected to the center (G0) is a ridge line, the n tops (TP1 to TPn) are central axes of the
regular n-gon ( The diaphragm (100) is characterized in that it is on an outer peripheral line (C2)
of a figure rotationally symmetric about an eccentric axis (O3) eccentric to G0). [4] At a position
where the n tops (TP1 to TPn) and the center (G0) of the regular n-gon protrude on one side with
respect to the plane (P0) including the respective vertices (T1 to Tn) It is a diaphragm (100) as
described in [3] characterized by one.
[5] The center (G0) of the regular n-gon and each vertex (T1 to Tn) and the n tops (TP1 to TPn)
are on the same spherical surface (CF) [4] It is a diaphragm (100) as described in. [6] The
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diaphragm (10, 10R, 100) according to any one of [1] to [5], and a flexible member connected to
the outer portion (14) of the diaphragm (10, 10R, 100) A connecting member (30) having
flexibility, a frame (31) for vibratably supporting the diaphragm (10, 10R, 100) via the
connecting member (30), and the diaphragm (10, 10R, 100) And 100) a drive unit (32) having a
voice coil bobbin (21) connected to one surface side of the inner-shaped portion (13) for
vibrating the diaphragm (10, 10R, 100). It is an electroacoustic transducer (50, 50A) that is
characterized.
[0009]
According to the present invention, it is possible to suppress the generation of standing waves,
obtain high sound pressure even in the low sound range, perform electroacoustic conversion of
input signals with high efficiency, and clarify the reference direction of sound emission, The
effect is obtained that uniform directional characteristics can be obtained in the circumferential
direction.
[0010]
An embodiment of the present invention will be described by way of a preferred embodiment
with reference to FIGS.
FIG. 1 is a schematic perspective view showing a diaphragm of a first embodiment according to
the present invention. FIG. 2 is a plan view and a sectional view showing a diaphragm of a first
embodiment according to the present invention. FIG. 3 is a cross-sectional view showing the
electro-acoustic transducer of the first embodiment according to the present invention. FIG. 4 is a
cross-sectional view showing another example of the electroacoustic transducer according to the
first embodiment of the present invention. FIG. 5 is a schematic view for explaining the standing
wave distribution in the conventional diaphragm. FIG. 6 is a schematic view for explaining the
standing wave distribution in the diaphragm of the first embodiment according to the present
invention. FIG. 7 is a graph showing frequency-sound pressure characteristics according to the
amount of eccentricity of the diaphragm. FIG. 8 is a schematic cross-sectional view for explaining
the diaphragm shape of the first embodiment according to the present invention. FIG. 9 is a
schematic cross-sectional view for explaining another shape of the diaphragm of the first
embodiment according to the present invention. FIG. 10 is a plan view and a sectional view
showing a modification of the diaphragm of the first embodiment according to the present
invention. FIG. 11 is a front view for comparing and explaining the conventional diaphragm and
the diaphragm of the second embodiment of the present invention. FIG. 12 is a schematic crosssectional view for explaining an electro-acoustic transducer according to a second embodiment of
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the present invention. FIG. 13 is a developed view for explaining a diaphragm of an application
example of the present invention. FIG. 14 is an external view showing an electroacoustic
transducer according to an application example of the present invention. FIG. 15 is a perspective
view for explaining the structure of an electroacoustic transducer according to an application
example of the present invention. FIG. 16 is a partial cross-sectional view for explaining the
structure of an electroacoustic transducer according to an application example of the present
invention. FIG. 17 is another perspective view for explaining the structure of the electroacoustic
transducer of each of the embodiments according to the present invention. FIG. 18 is a front view
and a perspective view for explaining a modification of the diaphragm of the application example
of the present invention. FIG. 19 is a front view for explaining an electro-acoustic transducer of
an application example of the present invention. In the following description, rotational
symmetry means at least two or more rotational symmetries.
[0011]
First Embodiment The shape of the diaphragm of the first embodiment will be described with
reference to FIGS. 1 and 2. FIG. FIG. 1 shows a plurality of radial solid lines 16 schematically
showing the curvature so that the curved surface shape of the diaphragm 10 can be easily
understood. FIG. 1 is a perspective view showing the appearance of the diaphragm 10, FIG. 2 (a)
is a plan view showing the diaphragm 10, and FIG. 2 (b) is S1-S1 in FIG. 2 (a). FIG.
[0012]
As shown in FIGS. 1 and 2, the diaphragm 10 has a central portion 11 ranging from a central axis
O to a diameter D1 [see FIG. 2 (a)] and a diameter D2 from the inner diameter portion 13 to the
diameter D2. It forms in the substantially disk shape which consists of the inclination part 12
which is the range to the outer-diameter part 14 which becomes [refer FIG. 2 (a)]. The material of
the diaphragm is not particularly limited, and sheets made of paper, resin such as PP
(polypropylene), metal such as aluminum, ceramic, or wood may be used.
[0013]
The inner diameter portion 13 is formed so as to protrude by the maximum height h1 [see FIG. 2
(b)] with respect to the reference plane P0 including the outer diameter portion 14, and the
central portion 11 inside thereof is the most projecting portion. It has a curved surface which is
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recessed with respect to a certain inner diameter portion 13 by a depth h2 (see FIG. 2B).
Accordingly, the inner diameter portion 13 forms a circular ridge having a diameter D1. The
inclined portion 12 is formed as a surface connecting the inner diameter portion 13 and the
outer diameter portion 14. In addition, an intermediate diameter portion 15 (indicated by a twodot chain line) having a diameter D3 is formed between the inner diameter portion 13 and the
outer diameter portion 14. The intermediate diameter portion 15 is a portion (inflection portion)
where the curvature of the surface of the inclined portion 12 changes significantly.
[0014]
More specifically describing the diaphragm 10, the surface (hereinafter referred to as the
inclined portion inner side surface 12a) of the region on the inner side (the side of the central
axis O) of the intermediate diameter portion 15 in the inclined portion 12 has a curvature in the
concave direction. As a curved surface, the surface of the region outside the intermediate
diameter portion 15 (opposite to the central axis O) (hereinafter referred to as the inclined
portion outer surface 12b) is formed as a flat surface having no curvature. . Further, the
intermediate diameter portion 15 has a central axis O2 eccentric to the central axis O of the
inner diameter portion 13 and the outer diameter portion 14 by a distance α (an eccentricity
amount α). Therefore, with the intermediate diameter portion 15 as a boundary, a portion where
the curvature is discontinuous between the eccentric central surface O2 side surface (inclined
inner surface 12a) and the opposite surface (inclined outer surface 12b) And is shown as a line
circling about the eccentric central axis O2.
[0015]
In addition, the curvature R of the inner surface 12a of the inclined portion is not constant, and
changes continuously from the maximum Rmax to the minimum Rmin in the circumferential
direction (see FIG. 2B), based on the changing curvature R and the eccentric distance α. Thus,
the inclined inner surface 12a is formed.
[0016]
Next, an electroacoustic transducer 50 using the above-described diaphragm 10 will be
described.
The electro-acoustic transducer 50 is also referred to as a speaker unit, and for example, as
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shown in FIG. 3, a diaphragm 10 and a flexible edge 30 connected to the outer diameter portion
14 side of the diaphragm 10; A housing 31 to which the edge 30 is fixed and a magnetic circuit
34 fixed to the housing 31 for driving the diaphragm 10 are included.
[0017]
The magnetic circuit 34 includes a cup-shaped yoke 23 having a bottom 23 and an annular wall
23 b, a magnet 24 fixed to the inner surface of the bottom 23 a, and a cylindrical pole piece 25
fixed to the magnet 24. Configured The edge 30 which is a connecting member for connecting
the diaphragm 10 and the housing 31 can be made of rubber or resin as an example. The voice
coil bobbin 21 and the voice coil 22 wound around the outer peripheral surface on one end side
thereof are inserted into the gap between the annular wall portion 23 b of the yoke 23 and the
pole piece 25. The voice coil 22 is externally charged through a lead wire 22 a, and the lead wire
22 a is drawn out from a hole 31 a provided in the housing 31. Further, the voice coil bobbin 21
is connected to the housing 31 by the damper 33 having an outer peripheral surface thereof
having elasticity, and the housing 31 can freely vibrate in a direction (vibration direction) parallel
to the central axis O of the diaphragm 10 via the damper 33. It is supported by A drive unit 32 is
configured to include the magnetic circuit 34, the voice coil bobbin 21 and the voice coil 22.
[0018]
Although partially overlapping, in more detail, the diaphragm 10 has a flexible annular edge 30
fixed in the vicinity of the outer diameter portion 14, and the outer peripheral portion of the
edge 30 is the annular shape of the housing 31. It is fixed to the frame 31b. At the time of this
fixing, the diaphragm 10 is attached in such a direction that the inner diameter portion 13
protrudes on the opposite side to the drive portion 32.
[0019]
One end of a circular voice coil bobbin 21 is fixed to the surface on the opposite side to the
projecting direction of the circular ridge-shaped projecting inner diameter portion 13. A voice
coil 22 is wound around the outer peripheral surface of the other end of the voice coil bobbin 21.
Further, the cup-shaped yoke 23 is disposed such that the inner wall surface 23a faces the voice
coil 22 with a predetermined magnetic gap.
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[0020]
On the other hand, the outer peripheral surface of the disk-shaped pole piece 25 connected to
the cylindrical magnet 24 has a predetermined gap with the inner surface of the voice coil
bobbin 21 inside the portion of the voice coil bobbin 21 where the voice coil 22 is wound. Are
arranged to face each other. The voice coil bobbin 21 is supported by the housing 31 via the
damper 33 so as to be movable in the vibration direction.
[0021]
The edge 30, the housing 31, and the drive unit 32 used in the above-described electroacoustic
transducer 50 can use general-purpose components whose outer shape is formed noneccentrically with respect to the central axis O as they are. Since it is not necessary to use, cost
increase can be suppressed.
[0022]
The direction in which the inner diameter portion 13 of the diaphragm 10 protrudes with respect
to the drive portion 32 may be directed to the drive portion 32 side in the opposite direction to
the direction of FIG. 3 described above.
That is, the configuration is such that the inner diameter portion 13 is in a depression direction,
and this example is shown in FIG. In the electro-acoustic transducer 50A of FIG. 4, the projecting
direction of the diaphragm 10 is opposite to that of the electro-acoustic transducer 50 of FIG. 3,
and one end side of the voice coil bobbin 21 corresponds to the inner diameter portion 13 of the
diaphragm 10. It adheres to the surface of the side which protruded. Other than this is the same
as the electroacoustic transducer 50. Therefore, as the voice coil bobbin 21, one having a length
in the central axis O direction shorter than that used for the electroacoustic transducer 50 can be
used.
[0023]
The electroacoustic transducer 50 in which the inner diameter portion 13 protrudes to the
outside as shown in FIG. 3 has a wider directivity than the electroacoustic transducer 50A in
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which the inner diameter portion 13 falls to the inside as shown in FIG. It is suitable for an
electro-acoustic transducer (so-called tweeter) that outputs high-pitched sound whose directivity
is hardly wide. Further, the electro-acoustic transducer 50A in which the inner diameter portion
13 is depressed inward is suitable for a large aperture electro-acoustic transducer (so-called
woofer) because the diaphragm 10 does not protrude outward.
[0024]
Next, in the case where the diaphragm 10 having the central axis O2 eccentric to the central axis
O of the outer diameter portion 14 as described above is used, and the central axis O2 of the
intermediate diameter portion 15 is The comparison of the characteristics etc. in the case where
the diaphragm which is not eccentric | decentered is used, and is demonstrated below.
[0025]
5 and 6 show a diaphragm 10a (comparative example) in which the central axis O2 of the
intermediate diameter portion 15 is not eccentric with respect to the central axis O, and a central
axis O2 in which the intermediate diameter portion 15 is eccentric. The state of vibration of the
diaphragm with respect to the diaphragm 10 of the embodiment of the invention is shown.
5 and 6 apply to the voice coil 22 a force obtained from the effective coil length and the number
of turns of the voice coil 22 under the actual magnetic field strength of the magnetic circuit 34
as an analysis condition of the vibration, The distribution of the standing wave in the AA cross
section of the central axis O direction of each diaphragm when vibration is 12 kHz is shown.
[0026]
In these drawings, the upper drawing is a plan view of the diaphragm, and the displacement of
the vibration is shown on the lower side correspondingly. Specifically, in the lower displacement
amount diagram, the broken line indicates the cross-sectional shape of the diaphragm, and the
solid line indicates the standing wave distribution. In addition, this displacement amount is drawn
exaggeratingly. From the comparison of the figures, it can be seen that when the diaphragm 10
of the embodiment is used, the standing wave is clearly asymmetric with respect to the central
axis O. In addition, the number of peaks significantly generated with respect to the central axis O
is also different.
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[0027]
FIG. 7 shows the diaphragm 10a as a comparative example shown in FIG. 5 in which the central
axis O2 of the intermediate diameter portion 15 and the central axis O coincide (that is, the
eccentricity is 0.0 mm), and the central axis of the intermediate diameter portion 15 The
frequency-sound pressure characteristic in the electroacoustic transducer which respectively
used two types of examples of the diaphragm 10 which O2 eccentrically set 1.5 mm and 3.0 mm
as eccentricity (alpha) from the central axis O is shown.
[0028]
When the diaphragm 10a of the comparative example is used, a deep dip is observed around 8
kHz (refer to the arrow). However, if there is eccentricity as in the example, the larger the amount
is, the dip is flatter than embedded Turn out to
Also, it is understood that the other peaks and dips become smooth by decentering, and become
flatter as the amount of eccentricity α becomes larger.
[0029]
By the way, the inclined portion inner side surface 12a of the portion between the inner diameter
portion 13 and the intermediate diameter portion 15 is, for example, a curved surface as shown
in FIGS. May be [FIGS. 8 (a) to 8 (c) are schematic views showing the case where the intermediate
diameter portion 15 has a central axis O2 eccentric to the left direction of the figure with respect
to the central axis O of the outer diameter portion 14] There is. Specifically, FIGS. 8 (a) and 8 (c)
are examples in which the inclined portion inner side surface 12a is an inclined curved surface
having a curvature that is recessed inward in this cross-sectional shape. Further, in FIG. 8B, while
the inclined portion inner side surface 12a is an inclined surface having a curvature such that the
inner diameter portion 13 side is concaved inward in this cross sectional shape, the outer
diameter portion 14 side has a curvature in the cross sectional shape. It is an example made into
the inclined plane which does not have.
[0030]
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On the other hand, the sloped portion outer side surface 12b of the portion between the
intermediate diameter portion 15 and the outer diameter portion 14 of the sloped portion 12
may be a curved surface as shown in FIGS. 8 (a) to 8 (c). Specifically, as shown in FIG. 8A, it may
be a non-inclined plane, or it may be an inclined plane that is continuous from the inner side
surface 12a of the inclined portion connected as shown in FIG. 8B. Further, as shown in FIG. 8C,
it may be an inclined curved surface which is inclined in the opposite direction to the inclined
portion inner side surface 12a, or an inclined flat surface 12b1 as shown by a broken line.
[0031]
Further, the inclined portion inner side surface 12a may be an inclined plane having no curvature
in the cross-sectional shape as shown in FIGS. 9 (a) to 9 (c). (FIGS. 9A to 9C are also schematic
views, showing the case where the intermediate diameter portion 15 has a central axis O2
eccentric to the left direction of the figure with respect to the central axis O of the outer diameter
portion 14 ing. In addition, the inclined portion outer side surface 12b may be a non-inclined flat
surface as shown in FIG. 9A, or may be an inclined flat surface inclined in the same direction as
the inclined portion inner side surface 12a as shown in FIG. As shown in 9 (c), it may be an
inclined plane inclined in the opposite direction to the inclined portion inner side surface 12a.
[0032]
Of course, the shape of the inclined portion 12 may be a combination of those shown in FIGS. 8
and 9, and is not limited thereto. As shown in FIGS. 8 and 9, in the diaphragm 10 of this
embodiment, the cross-sectional shape in the S-S cross section orthogonal to the central axis O is
a central axis O5 eccentrically with respect to the central axis O by α2 And has a rotationally
symmetrical shape about the eccentric central axis O5.
[0033]
In the inclined portion 12, the position d1 of the reference plane P0 including the outer diameter
portion 14 in the direction of the central axis O (the position where the reference plane P0
intersects the central axis O) to the position d2 of the inner diameter portion 13 (in the central
axis O) The cross section having a rotationally symmetrical shape about such an eccentric central
axis O5 is not limited to the one having a rotationally symmetrical shape about the eccentric
central axis O5 at all positions up to the surface P13 including the inner diameter portion 13)
The diaphragm may have a shape in which the position d partially exists as an eccentric surface
portion.
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[0034]
Further, except for the example shown in FIG. 8B, the intermediate diameter portion 15 is a
portion where the inclination angle or the curvature of the surface of the inclined portion 12
suddenly changes, in other words, two portions connecting the portion as a boundary. It is set as
a portion where the curvature or inclination angle of the surface is discontinuous.
In addition, the intermediate diameter portion 15 is a portion visually recognized as a boundary
line in which the degree of reflection of light projected from one direction is different. The
intermediate diameter portion 15 is not limited to a perfect circle, and may be a rotationally
symmetrical figure having a central axis O2 eccentric to the central axis O and having the
eccentric center O2. Further, the inner diameter portion 13 is not limited to a perfect circle, and
may be, for example, a rotationally symmetric figure such as an ellipse.
[0035]
In the embodiment described above, the diaphragm 10 having the concaved surface of the
central portion 11 has been described, but the central portion 11 may be a flat surface or may
have a projecting surface. Further, the size of the central portion 11, in other words, the radial
size of the inner diameter portion 13 may be set arbitrarily. Therefore, for example, when the
inner diameter portion 13 is a true circle, the size of the diameter D1 is arbitrary.
[0036]
Although the diaphragm 10 mentioned above demonstrated the example whose the external
shape is circular, it is good also as an external shape inscribed in a circle (for example, regular
pentagon). In this case, the dimensions may be set so that the outer shape of the polygon and the
intermediate diameter portion do not interfere with each other. Further, as shown in FIG. 10, the
inclined portion outer side surface 12b may be a curved surface having a curvature center O4 on
the side opposite to the projecting direction of the inner diameter portion 13. FIG. 10 shows, as
an example, the cross-sectional shape of a diaphragm 10R in which the inclined portion outer
side surface 12b is formed by a curved surface along a spherical surface CF having a radius R1.
The diaphragm 10R has the same shape as the diaphragm 10 of FIG. 2 except for the inclined
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portion outer side surface 12b.
[0037]
As described above, since the inner diameter portion 13, the outer diameter portion 14 and the
middle diameter portion 15 are not limited to the circle, including the case of the circle, the inner
shape portion 13, the outer shape portion 14 and the middle shape portion 15 respectively. It
can be written as
[0038]
The diaphragm 10 described in detail above has a central axis in which the outer diameter
portion 14 and the inner diameter portion 13 are coaxial even if there is an intermediate
diameter portion 15 having a central axis O2 eccentric to the central axis O of the outer diameter
portion 14 Since O is included, the electroacoustic transducer (speaker unit) 50 can be
configured using the drive unit 32 having the general edge 30, the housing 31, or the magnetic
circuit 34.
In addition, again, the outer diameter portion 14 and the inner diameter portion 13 are formed to
have the central axis O of the coaxial, and the center which is eccentric from the central axis O of
the outer diameter portion 14 and the inner diameter portion 13 by a predetermined distance α
When the intermediate diameter portion 15 having the axis O2 is provided, generation of a
symmetrical standing wave with respect to the central axis O is suppressed, and peaks and dips
in the frequency-sound pressure characteristic are smoothed to smooth it. Can. In the inclined
portion 12, the cross-sectional shape in any S-S cross section orthogonal to the central axis O has
a central axis O5 eccentric to the central axis O and rotates about the eccentric central axis O5.
Also in the case of a symmetrical shape, generation of a symmetrical standing wave with respect
to the central axis is similarly suppressed, and peaks and dips in the frequency-sound pressure
characteristics can be smoothed out.
[0039]
Second Embodiment Next, a diaphragm 100 according to a second embodiment of the present
invention will be described with reference to FIG. FIG. 11 shows the diaphragm 100a which is the
basic shape of this embodiment as FIG. 11 (a) and the diaphragm 100 as FIG. 11 (b) in order to
make it easy to grasp the shape of the diaphragm 100. It is a schematic plan view. In addition, in
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FIGS. 11A and 11B, black circles are attached to points where the line segments intersect for
easy understanding.
[0040]
The diaphragm 100 of this embodiment shown in FIG. 11 (b) is positioned on the center axis O of
the outer shape with the diameter D1 which can be arbitrarily set in the inner diameter portion
13 of the first embodiment substantially zero. The top portion TP0 is located at a position
projecting to one side with respect to the reference plane P0 set by including the diameter
portion 14, while the circumference around an axis eccentric to the central axis O between the
top portion TP0 and the outer shape In the diaphragm, a rotationally symmetric virtual graphic is
set, and a plurality of apexes projecting on the same side as the apex TP0 are provided on the
virtual graphic.
[0041]
The diaphragm 100 has a shape in which a plane substantially orthogonal to the sound radiation
direction (direction of the central axis O) is almost eliminated.
The outer shape of the diaphragm 100 may be a regular n-gon (n: an integer of 4 or more). Here,
as shown in FIG. 11B, an example of a regular pentagon in which n = 5 is described.
[0042]
First, a diaphragm 100a having a basic shape shown in FIG. 11 (a) will be described. The
diaphragm 100a is a regular pentagon whose outer shape has apexes T1 to T5. Each vertex is
located on the circumscribed circle C1. It is surrounded by the line segments T1G to T5G
connecting the center G0 of the regular pentagon (hereinafter also referred to as the main center
G0) and the vertices T1 to T5 and the sides T1T2 to T5T1 which are line segments connecting
between adjacent vertices The five triangles TR1 to TR5 and the centers of gravity G1 to G5 of
these triangles TR1 to TR5 are set. (In the example of this diaphragm 100a, each gravity center
G1-G5 corresponds with each center of triangle TR1-TR5)
[0043]
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15
Here, the diaphragm 100a has a top portion TP0 at which the main center G0 and the positions
of the respective gravity centers G1 to G5 protrude to one side with respect to a reference plane
P0 determined by including the respective apexes T1 to T5. And it is set as the shape which has
the uneven surface broken by each line segment so that it may become top part TP1-TP5.
Specifically, the line segments T1G to T5G connecting the vertices T1 to T5 and the main center
G0 are valley folds that become valley lines, and ten lines connecting the vertices T1 to T5 and
the centers of gravity G1 to G5 A mountain fold is used as the ridge line (mountain line). Further,
the five top portions TP1 to TP5 are located on a circle C2 centered on the main center G0.
[0044]
With respect to the diaphragm 100a having a basic shape having such a concavo-convex surface,
as shown in FIG. 11 (b), the diaphragm 100 of the embodiment is configured such that the
positions of the tops TP1 to TP5 As the line connecting TP5 is on the circle C2, and the center O3
of the circle C2 is decentered by a predetermined amount α from the main center O of the
regular pentagon (which coincides with the center of gravity G0 in this example) It has a shape
moved to FIG. 11B shows an example in which the eccentric direction is a direction (arrow
direction) approaching the vertex T1.
[0045]
Further, the diaphragm 100 is formed such that the main center G0 (the top portion TP0) and
the top portions TP1 to TP5 project to one side with respect to the reference plane P0. Each
protrusion amount with respect to the reference plane P0 may be arbitrary. Therefore, the main
center G0 (top portion TP0) may be most protruded with respect to the reference plane P0, and
may be smaller (lower) than any of the top portions TP1 to TP5. Of course, the amount of
protrusion may be the same. As described above, it is preferable that all the tops TP0 to TP5 be
in a position where they project to one side with respect to the reference plane P0, but only the
tops TP1 to TP5 may be in a position where they project to one side. Further, a line segment
connecting such apexes TP1 to TP5 with the respective apexes T1 to T5 and the main center G0
is a ridge line which is a mountain fold line.
[0046]
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16
Here, when the main center G0 is lower than the tops TP1 to TP5, the ridge line going from each
of the tops TP1 to TP5 to the main center G0 is down, but the ridge line going from each vertex
T1 to T5 to the main center G0 is up Therefore, the main center G0 is conveniently referred to as
the top TP0. Similarly, when the main center G0 is higher than the respective tops TP1 to TP5,
the ridge line extending from the main center G0 to each of the tops TP1 to TP5 is downward,
but the ridge line extends from each apex T1 to T5 to the respective tops TP1 to TP5 The tops
are referred to as tops TP1 to TP5 for convenience.
[0047]
In the case where the amount of protrusion of each of the top portions TP1 to TP5 with respect
to the reference plane P0 is different, the vibration plate 100 may not have all the top portions
TP1 to TP5 included in the same plane. Further, all the top portions TP1 to TP5 may be included
in the same plane, and the plane may be nonparallel to the reference plane P0.
[0048]
The diaphragm 100 of this embodiment is not limited to the one having the regular pentagonal
shape described above, but may be one having a regular n-gonal shape. That is, this diaphragm
has an outer shape of a regular n-gon (n: an integer of 4 or more), and the n-divided n-division by
a line connecting the center (centroid) G0 and each vertex T1 to Tn The center O3 of the figure
drawn by the line C2 connecting the points TP1 to TPn is a regular n-gon shape, and the
positions of arbitrary points TP1 to TPn in each range in n triangles TR1 to TRn obtained by The
center G0 and the points TP1 to TPn are set to be eccentric from the center G0 by a distance α,
and are positioned as apexes projecting on one side with respect to a reference plane P0 set by
including the respective apexes T1 to Tn. It is a diaphragm having a shape.
[0049]
Here, the line C2 connecting the points TP1 to TPn may not be a circle, and may be a rotationally
symmetric figure. The main center G0 and the apexes TP1 to TPn may protrude to one side with
respect to the reference plane P0 including the vertices T1 to Tn, and the amount of projection
with respect to the reference plane P0 is arbitrary. As described above, it is preferable that all the
tops TP0 to TPn be in a position where they project to one side with respect to the reference
plane P0, but only the tops TP1 to TPn may be in a position where they protrude to one side. In
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17
addition, a line segment connecting such apexes TP1 to TPn, the apexes T1 to Tn, and the main
center G0 is a ridge line which is a mountain fold line.
[0050]
Therefore, the main center G0 may be most protruded with respect to the reference plane P0,
and may be smaller (lower) than any of the tops TP1 to TPn. Of course, the amount of protrusion
may be the same. In the diaphragm 100, the respective top portions TP1 to TPn may not be all
included in the same plane when the projection amounts of the top portions TP1 to TPn with
respect to the reference plane P0 are different. In this case, the tops TP1 to TPn may be included
in the same plane, and the plane may not be parallel to the reference plane P0.
[0051]
The inner peripheral portion of the edge 30 is connected to the outer peripheral portion of the
diaphragm 100 using the diaphragm 100 described above and an edge 30 having an inner
peripheral shape corresponding to the outer shape of the diaphragm 100 and having a circular
outer shape. And the outer peripheral portion of the edge 30 is fixed to a general-purpose frame
having a circular frame, the diaphragm 100 is vibratably supported by the frame via the edge 30.
The (speaker unit) can be manufactured easily and with less cost increase by using a drive unit
having a general-purpose frame or a magnetic circuit.
[0052]
Further, in the diaphragm 100, it is preferable to join the voice coil bobbin 21 at a position
corresponding to at least each of the top portions TP1 to TPn because the vibration of the voice
coil bobbin 21 can be transmitted to the diaphragm 100 more efficiently.
Further, if the voice coil bobbin 21 is fixed to the surface of the diaphragm 100 opposite to the
side where the tops TP1 to TPn project, wider directivity can be obtained. An example in which
the diaphragm 100 and the voice coil bobbin 21 are connected in this manner is schematically
shown in FIG. In this FIG. 12, the sound is emitted so as to have broad directivity characteristics,
as indicated by the arrows in the figure. FIG. 12 corresponds to the B-B cross section of the
diaphragm 100 shown in FIG. 11B, where the intersection of the line segment T1G on the
diaphragm 100 and the circle C2 as a rotationally symmetric figure is BC1 and the side T3T4.
The middle point of is BC2.
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[0053]
The voice coil bobbin 21 is formed to have a cylindrical portion 21 a and a joint portion 21 b
connected to one end side thereof and enlarged toward the opening side. The voice coil 22 is
wound around the outer peripheral surface of the other end side of the cylindrical portion 21a.
The tip of the joint portion 21 b is adhesively fixed at a position corresponding to a circle C2 (see
FIG. 11B) connecting the top portions TP1 to TP5 of the diaphragm 100. Further, the voice coil
bobbin 21 is fixed so that its tube axis Ob and an axis passing through the top portion TP0 of the
diaphragm 100 and orthogonal to the reference plane P0 (that is, the central axis O of the outer
shape of the diaphragm 100) coincide. Ru. The tube axis Ob of the voice coil bobbin 21 coincides
with the central axis of the drive unit 32.
[0054]
In the electroacoustic transducer using this diaphragm 100, the distribution of the standing wave
becomes asymmetric with respect to the axis in any cross section including the central axis O,
and the frequency − as described above with reference to FIG. The effect is obtained that the dip
or peak in the sound pressure characteristic is flattened.
[0055]
Further, in the electro-acoustic transducer using this diaphragm 100, the diaphragm 100 has no
plane orthogonal to the central axis O, and both planes are inclined, so that the center which is
the front of the diaphragm 100 is Even in the high sound range where the listening area close to
the axis O tends to have high sound pressure and sharp directivity, the decrease in sound
pressure (difference in sound pressure to the front) caused by the angle made with respect to the
central axis O becomes small. Properties close to sex are obtained.
If the directional characteristics have characteristics close to omnidirectional, they are useful in
use environments where the listening position is not limited to a narrow range, for example, use
in halls, large rooms, streets, etc., and are close to this electroacoustic transducer In the case of
listening at a position, localization of the sound does not greatly shift even if the listening
position is shifted, and it is very preferable because the user can listen with natural localization
movement.
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[0056]
Furthermore, in the diaphragm 100 of this embodiment, the diaphragm shape of the diaphragm
100 according to the present embodiment provides a characteristic with less sound pressure
difference depending on the listening position and a characteristic close to no directivity. Is the
most projecting, and it is found that the projecting main center G0 and the tops TP1 to TPn and
the apexes T1 to Tn of the outer shape are included in the spherical surface with a constant
curvature. This is because the diaphragm 100 as a whole has a shape close to a part of a
spherical surface, although there are fine irregularities in the surface shape. Therefore, the
radiation axis in the sound emitting direction is more uniformly distributed in the direction
orthogonal to the spherical surface throughout the diaphragm 100.
[0057]
Therefore, in the electroacoustic transducer using the diaphragm 100 of this shape, not only is
the dip or peak in the frequency-sound pressure characteristic flattened, but also the sound
pressure difference due to the difference in the angle made with respect to the vibration
direction of the diaphragm. Becomes smaller, and the near directivity is obtained.
[0058]
Here, when n having a regular n-gon indicating the external shape of the diaphragm 100 of the
second embodiment described above is infinite, the external shape of the diaphragm 100
becomes a circle, and the plurality of apexes TP1 to TPn are infinite. It is the top of the number.
The top of the infinite number is a circumferential line (diaphragm) in which this is a line which
continuously revolves around the central axis O, and the curvature or inclination angle of the two
surfaces connected with the line as a boundary is discontinuous (Corresponding to the
intermediate diameter portion 15 of 10). That is, the diaphragm 10 of the first embodiment can
be regarded as n being infinite in the diaphragm 100 of the second embodiment, and the
diaphragms 10 and 100 of the first and second embodiments are the present embodiment. It is
easily understood from this that there are two possible forms according to the technical concept
of the invention.
[0059]
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20
<Example of Application> Next, the outer shape of the diaphragm 10 of the first embodiment
described above is a regular pentagon, and this is expanded and arranged as shown in FIG. A
diaphragm 200 in the form of a face and an electroacoustic transducer 150 using the diaphragm
200 will be described in detail as an application example. Further, in this application example, an
application example of the diaphragm 201 and the electroacoustic transducer, which are
substantially regular dodecahedrons, using the diaphragm 100 of the second embodiment as the
diaphragm in place of the diaphragm 10 of the first embodiment. As a variation of The
diaphragms 200 and 201 have a form in which the flat plate-like diaphragms 10 and 100 are
respectively combined as described above, and in the following description, this form
corresponds to the form of the hollow sphere surface. It shall be regarded as a spherical shell
diaphragm (spherical shell diaphragm) for convenience, including the aspect of a regular
dodecahedron.
[0060]
The appearance of the electroacoustic transducer 150 of this application example is shown in
FIG. The electro-acoustic transducer 150 may be referred to as a sphere speaker or the like in
view of its form, or a breathing sphere speaker or the like in view of the vibration mode of the
diaphragm 200.
[0061]
The electroacoustic transducer 150 includes a substantially spherical shell-shaped diaphragm
200 (hereinafter, also referred to as a spherical shell diaphragm 200 to distinguish it from a
single diaphragm as described above), the spherical shell diaphragm 200. And a drive unit 232
(not shown) having a magnetic circuit 234 (not shown) for driving the spherical shell diaphragm
200 in the radial direction, and the outer side of the spherical shell diaphragm 200 supporting
the drive unit 232. And a supporting leg 103 extending to the
[0062]
Although the details will be described later, the magnetic circuit 234 is composed of a cupshaped yoke 223, a magnet 224 fixed to the inner surface of the bottom 223a of the yoke 223,
and a pole piece 225 fixed to the magnet 224.
12-05-2019
21
Further, the drive unit 232 is configured by the magnetic circuit 234, the voice coil bobbin 221,
and the voice coil 222.
[0063]
Here, the spherical shell diaphragm 200 will be described with reference to FIG. 13. As described
above, in the spherical shell diaphragm 200, eleven diaphragms 10 each having an outer shape
of a regular pentagon are prepared. Ten sides are butted and joined together by a flexible edge
102 to form 11 sides of a regular dodecahedron. In other words, the surface of a sphere having a
predetermined diameter is approximately divided into 12 regular pentagons, and the diaphragm
10 is applied to each of 11 of the 12 regular pentagons divided. is there. Therefore, as the
diaphragm 200, there is no one surface of the regular dodecahedron, which is an opening.
Hereinafter, the individual diaphragms 10 are also referred to as segments 101.
[0064]
Referring back to FIG. 14, one of the 12 surfaces (the surface shown by the arrow in FIG. 14),
which is the opening, is a plate (shown in FIG. 14) having a hole through which the support leg
103 is inserted. Closed). This plate is joined to the spherical shell diaphragm 200 via the flexible
edge 102. Further, the support leg 103 inserted into the hole is also fixed in the hole. An
installation pedestal (not shown) is attached to one end 103 a of the support leg 103, and the
electro-acoustic transducer 150 itself can be installed on a floor surface or suspended from a
ceiling.
[0065]
The electro-acoustic transducer 150 is provided with a total of eleven driving parts 232, one for
each of the diaphragms 10, as apparent from FIG. 15 showing the state where the spherical shell
diaphragm 200 is removed.
[0066]
Next, the configuration of the drive unit 232 and the like corresponding to one segment 101
which is each diaphragm 10 will be described with reference to FIG.
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22
In FIG. 16, the housing 31 is removed from FIG. 3, and the end of the diaphragm 10 as the
segment 101 and the end of the diaphragm 10 adjacent to each other are connected via the edge
102 as the connecting member. Is shown. Moreover, the adjacent diaphragm 10 has described
the one part.
[0067]
One end portion of a circular tubular voice coil bobbin 221 is connected and fixed to the
diaphragm 10 on the surface opposite to the projecting surface of the inner diameter portion 13.
In this state, the central axis O of the outer shape of the moving plate 10 and the tube axis Ob of
the voice coil bobbin 221 coincide with each other. The voice coil 222 is wound around the outer
peripheral surface of the voice coil bobbin 221 on the other end side. Outside the voice coil 222,
a cup-shaped yoke 223 is disposed so that the inner peripheral surface of the annular wall 223a
faces the outer peripheral surface of the voice coil 222 with a gap. Further, inside the voice coil
bobbin 221, a cylindrical pole piece 225 coupled to the magnet 224 is disposed so as to have a
gap with the inner circumferential surface thereof. In addition, a ring-shaped frame 235 is fixed
to the yoke 223. The voice coil bobbin 221 and the frame 235 are connected by two dampers
233 having elasticity, and the voice coil bobbin 221 is elastically supported by the damper 233
so as to be movable in a direction parallel to the central axis O with respect to the frame 235 It is
done. The magnet 224 is fixed to the bottom 223 a of the yoke 223, and the yoke 223 is fixed to
the mounting surface 132 a of the support base 132. As this drive part 232, what is used in
order to drive the diaphragm which has an external shape centering on the tube axis Ob of the
voice coil bobbin 221 can be diverted as it is.
[0068]
As shown in FIG. 17, a total of 11 supporting bases 132 are attached to each of 11 of the 12
sides of the base 130 assembled into a substantially regular dodecahedron by the base frame
131. . Although not shown, the support legs 103 described above are fixed to the remaining one
surface of the base 130. Further, as shown in FIG. 16, in the mounting surface portion 132 a of
the support base 132, as described above, the bottom surface of the yoke 223 is a tube axis
which is a central axis of the central axis O12 of each surface of the regular dodecahedron and
the drive portion 232. It is fixed so that it matches Ob.
12-05-2019
23
[0069]
Accordingly, the electro-acoustic transducer 150 is fixed to the base 130 such that the mounting
surface portion 132a is positioned corresponding to the base 130 whose outer shape is a
substantially regular dodecahedron and the eleventh side of the regular dodecahedron. Eleven
support bases 132 and eleven drive parts 232 fixed to the mounting surface parts 132a of these
support bases 132 are provided, and the voice coil bobbin 221 of each drive part 232 has a
regular pentagonal outer shape The diaphragm 10 is assembled by connecting eleven of the
diaphragms 10 corresponding to the eleven faces of a regular dodecahedron, and is connected to
each diaphragm 10 of the spherical shell diaphragm 200 as a substantially spherical shell.
Therefore, the electroacoustic transducer 150 is supported such that the spherical shell
diaphragm 200 is aligned with the tube axis Ob by the voice coil bobbins 221 of the drive units
232 for the central axis O of each diaphragm 10, It is driven to vibrate in the normal direction of
the sphere circumscribing the regular dodecahedron, and emits sound.
[0070]
As a result, it is possible to emit the sound in almost all directions while extremely reducing the
sound pressure difference caused by the difference in emitting angle. Therefore, when the
electro-acoustic transducer 150 is disposed, for example, in a hole or the like to emit sound, a
sound field excellent in sense of reality is formed regardless of the listening position. In addition,
when listening to the sound emitted at a position close to the electroacoustic transducer 150,
even if the listening position moves, the localization of the sound moves naturally without
moving extremely, so a good sense of reality is obtained. can get.
[0071]
When the diaphragm 10 described above is used as an individual diaphragm, the shape of the
diaphragm 10 is such that the outer diameter portion 14 and the inner diameter portion 13 have
a central axis O coaxial with and coaxial with the central axis O2 When the intermediate diameter
portion 15 is provided, generation of symmetrical standing waves with respect to the central axis
O can be suppressed, and peaks and dips in the frequency-sound pressure characteristic can be
flattened. In addition, the shape of the diaphragm 10 is around the central axis O2 in which the
cross-sectional shape orthogonal to the central axis O in the inclined portion 12 has a central axis
O in which the outer diameter portion 14 and the inner diameter portion 13 are coaxial With the
eccentric surface portion having a rotationally symmetric shape, generation of symmetrical
12-05-2019
24
standing waves with respect to the central axis O can be suppressed, and peaks and dips in the
frequency-sound pressure characteristics can be flattened.
[0072]
Further, if diaphragm 10R which is a modification of diaphragm 10 as shown in FIG. 10 is used
as each diaphragm, it has a curved surface such that inclined part outer side surface 12b follows
a part of spherical surface CF. Since the spherical shell diaphragm 200 has an outer appearance
shape closer to a sphere, the appearance quality as a spherical speaker is improved.
[0073]
Next, as a modified example of this application example, using the diaphragm 100 (see FIG. 11B
and FIG. 18A) instead of the diaphragm 10, the eleven diaphragms 100 are inserted via the edge
102. FIG. 18B shows the appearance of a spherical shell diaphragm 201 which is formed into a
substantially spherical shell by bonding so that the respective sides are joined together.
The support leg 103 is omitted in this figure.
[0074]
As shown in FIGS. 18A and 18B, the outer shape of each diaphragm 100 is a regular pentagon
having apexes T1 to T5. Further, in FIG. 18A, the figure C2 connecting the apexes TP1 to TP5 is a
circle, and its center O3 is shifted from the main center G0 of the regular pentagon by a distance
α in the direction toward the apex T1. There is. Further, as can be seen from FIG. 18B, the main
center G0 and the tops TP1 to TP5 protrude outward with respect to the reference plane P0 set
including the vertices T1 to T5, and the amount of projection is the main center G0 is formed to
be the largest. Further, the voice coil bobbin 221 joined to the diaphragm 100 is the voice coil
bobbin 221 described with reference to FIG. 12 and includes the position corresponding to at
least each of the top portions TP1 to TP5 of the diaphragm 100, the surface on the drive portion
232 side. Adhesively fixed to
[0075]
When the spherical shell diaphragm 201 of this modification is used, each diaphragm 100 has
the center GO of the outer shape as the top TP0 projecting in one direction with respect to the
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25
reference plane P0 including the apexes T1 to T5 and Between the center G0 and the outer shape
(outer diameter portion 14), a plurality of protruding top portions TP1 to TP5 are provided and
the top portions TP1 to TP5 are connected to form a center O3 of the figure C2 from the center
G0 of the outer diameter portion 14 Since the diaphragm surface is formed to be decentered with
respect to the direction orthogonal to the reference plane P0 which is the sound emission
direction while being decentered, dips and peaks in the frequency-sound pressure characteristics
are flattened. In addition, the sound pressure difference due to the difference in the angle
between the center G0 and the axis perpendicular to the reference plane P0 (the central axis of
the diaphragm 100) decreases, and a characteristic close to no directivity can be obtained.
[0076]
Further, as described in detail in the description of the diaphragm 100, the shape of the
diaphragm 100 is made to project the center G0 most with respect to the reference plane P0, and
the projecting center G0, the plurality of apexes TP1 to TP5, and each vertex of the outer shape If
T1 to T5 are formed to be included in a spherical surface with a constant curvature, the sound
pressure difference due to the difference in the angle made with respect to the central axis O of
the diaphragm 100 becomes small, which is preferable in order to obtain nondirectionality.
[0077]
In addition, if the constant curvature is made to coincide with the curvature of the surface of the
spherical shell diaphragm 201, the entire shape of the spherical shell diaphragm 201 becomes
closer to a true sphere. Since the sound pressure difference due to the difference in the angle
formed is smaller and the directivity characteristic is smoother, it is more preferable because an
effect that the directivity characteristic as the spherical shell diaphragm 201 further approaches
non-directivity is obtained.
[0078]
When the spherical shell diaphragms 200 and 201 are formed using the diaphragms 10 and 10R
or the diaphragm 100 described above, if the eccentric direction of the diaphragms 10 and 100
is set to a predetermined direction, the electroacoustic transducer 150 is formed. Is preferably
installed on a floor surface, for example, since the sound pressure fluctuation is reduced when
the listening position to that position is particularly changed in the latitudinal direction (vertical
direction).
The eccentric direction will be described with reference to FIG.
12-05-2019
26
[0079]
In FIG. 19, this electro-acoustic transducer 150 is installed so that the diaphragm on the top
surface opposite to the plate of the bottom surface 10B to which the support legs 103 are
attached is the diaphragm 10T, and this is parallel to the floor surface FL. It is a front view which
shows a state.
This is an example of installation.
The diaphragm in FIG. 19 is a spherical shell diaphragm 200 using the diaphragm 10 of the first
embodiment. In this state, the side where the five diaphragms 10-1 to 10-5 connected to the
diaphragm 10T on the top surface and the five diaphragms 10-6 to 10-10 connected to the plate
on the bottom surface 10B are joined is 19 is a junction of the boundary which divides the
spherical shell diaphragm 200 into upper and lower parts in FIG. This line EQ is shown by a thick
broken line in FIG.
[0080]
Assuming that the spherical shell diaphragm 200 is the earth, the line EQ will be hereinafter
referred to as the equator EQ, the top side of the equator EQ as the northern hemisphere, and the
bottom side as the southern hemisphere. The preferable eccentric direction of the diaphragms 10
and 100 is a direction toward the apex on the equator EQ for the diaphragms 10-1 to 10-5 in the
northern hemisphere and the diaphragms 10-6 to 10-10 in the southern hemisphere. When the
eccentric direction is set as described above, it is preferable that the sound pressure fluctuation is
reduced when the listening position changes in the latitude direction (vertical direction in FIG.
19).
[0081]
Furthermore, it is more preferable that the eccentric direction of the diaphragms 10-1 to 10-5 in
the northern hemisphere and the eccentric direction of the diaphragms 106 to 10-10 in the
southern hemisphere be opposite in the circumferential direction as shown in FIG. Specifically, as
12-05-2019
27
shown by the arrows in FIG. 19, when viewed from the top, the diaphragms 10-1 to 10-5 in the
northern hemisphere are decentered clockwise toward the apex on the equator EQ, and the
southern hemisphere The diaphragms 10-6 to 10-10 may be decentered in the counterclockwise
direction toward the top of the line EQ. The clockwise rotation and the counterclockwise rotation
may be reversed. As described above, when the diaphragms on both sides connected by the line
EQ, which is a junction that divides the spherical shell diaphragm 200 into two, are decentered in
mutually different circumferential directions, the listening position changes in the latitude
direction The sound pressure fluctuation of is averaged and the fluctuation is further reduced.
[0082]
This line EQ is not limited to one set parallel to the floor surface FL. Depending on the listening
position, the direction of the line EQ can be appropriately set so as to be the optimum directivity
characteristic at the listening position. Further, since the support legs 103 may extend in any
direction, the extension direction of the support legs 103 does not restrict the setting direction of
the line EQ.
[0083]
On the other hand, when the listening position is assumed, it is preferable that the eccentric
direction of the diaphragm 10T on the top surface is set as the direction approaching the
listening position. In this way, the sound pressure fluctuation when the listening position moves
up and down at that position is further reduced.
[0084]
By the way, when the edge 102 is made of a particularly soft material, or when the spherical
shell diaphragms 200 and 201 are relatively large, the shape of the spherical shell diaphragms
200 and 201 is not distorted by the weight of the diaphragm itself. A support 236 may connect
between the edge 102 and the base 130 as shown by a two-dot chain line in FIG. The support
236 additionally supports the ball shell diaphragms 200 and 201 on the voice coil bobbin 221 to
support them, and has elasticity such that the shape of the diaphragm is not deformed and the
vibration is not affected. It is formed of the material which it has. The edge 102, which is a
connecting member for connecting the diaphragms 10, 10R, and 100 to each other, is bonded to
each of the diaphragms 10, 10R, and 100 using an adhesive. The diaphragms 10, 10R, and 100
12-05-2019
28
may be bonded to each other via an adhesive. In this case, it goes without saying that this
adhesive serves as a connecting member.
[0085]
<Manufacturing process> Next, the process of manufacturing the electroacoustic transducer 150
of an application example is demonstrated mainly using FIG. In this example, an example using a
substantially regular dodecahedron spherical shell diaphragm 200 formed by combining a
plurality of diaphragms 10 is described, but the diaphragm 10R or the diaphragm 100 may be
used instead of the diaphragm 10. It can be manufactured similarly.
[0086]
(Step 1) First, a flat plate or sheet diaphragm material is subjected to press processing, drawing
processing, or the like to form the diaphragm 10 corresponding to each segment 101. As this
diaphragm material, as described above, a sheet of paper, metal, resin, ceramic or wood can be
used. Each sheet may be a stack of one or more sheets.
[0087]
(Step 2) Next, 11 segments 101 are deployed and arranged on a plane as shown in FIG. 13, and
in this state, the sides of individual segments 101 that can be joined are butted, and respectively
through flexible edges 102. Joint. For example, a rubber material or resin material can be used
for the edge, and a known adhesive can be used for bonding.
[0088]
In this example, two segments 101 are continuously joined to each side of one center segment
101-C as a center. Specifically, in FIG. 13, the five segments 101-1 to 101-5 adjacent to one
central segment 101-C are joined, and the segments 101-1 to 101-5 are further segmented. Join
6 to 101-10. In this bonding mode, two sides (shown as stripes in FIG. 13) apart from the
segment 101-C become a line EQ.
12-05-2019
29
[0089]
Further, when developing on a plane, each segment 101 is directed such that the eccentric
direction of the intermediate diameter portion 15 of each segment 101 is directed to the vertex
on the line EQ after combination (arrow direction in FIG. Deploy. When the arrangement of FIG.
13 corresponds to FIG. 19, for example, the segment 101-C becomes the diaphragm 10T on the
top surface, and the segments 101-1 to 101-5 are diaphragms 10-1 to 10-5 on the northern
hemisphere side, The segments 101-6 to 101-10 become the diaphragms 10-6 to 10-10 on the
southern hemisphere side.
[0090]
(Step 3) On the other hand, as shown in FIG. 17, the support base 132 is fixed to each of 11 sides
of the base 130 which is formed in a substantially regular dodecahedron shape by combining the
base frames 131 in advance. Then, the bottom surface 223a of the yoke 223 is fixed to the
mounting surface portion 132a of the support base 132 with an adhesive or the like. A magnet
224 or the like to which the pole piece 225 is fixed in advance is attached to the yoke 223 to
form a drive portion 232 in advance.
[0091]
(Step 4) Align the movable part such as the voice coil bobbin 221 or the like on which the voice
coil 222 is wound with the fixed part such as the yoke 223 and the magnet 224 so that both are
at predetermined opposing positions as shown in FIG. , Attached through the damper 233.
Bonding in this attachment can also be performed using an adhesive. The assembled assembly
202 is shown in FIG.
[0092]
(Step 5) Next, the eleven segments 101 partially joined in (Step 2) are put on the assembly 202
to which the eleven driving parts 232 are attached. At that time, each segment 101 is put on to
correspond to each voice coil bobbin 221 attached in (Step 4). Then, the end of the voice coil
bobbin 221 is fixed to the inner surface of each segment 101 by an adhesive so that the central
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axis O of each segment 101 matches the tube axis Ob of the voice coil bobbin 221.
[0093]
(Step 6) In this state, since the sides not joined in (Step 2) in each segment 101 are positioned so
as to naturally but substantially abut each other, the adhesive agent is applied via the flexible
edge 102. The two pieces are joined to form a spherical shell diaphragm 200 having a
substantially spherical shell shape.
[0094]
(Step 7) The support leg 103 is fixed to the base 130, a plate closing the opening of the spherical
shell diaphragm 200 is disposed at the opening, and the plate is joined to the spherical shell
diaphragm 200 and the support leg 103.
The attachment between the support leg 103 and the base 130 is not limited to the end, and may
be performed in advance between any other steps. The electro-acoustic transducer 150 is
manufactured by the above process.
[0095]
According to this manufacturing process, in (Step 2), each side of bondable segments 101 is
bonded in advance in a state in which each segment 101 is developed on a plane, and in the
subsequent (Step 5) Since the respective sides are joined to each other, the alignment of the
opposing parts when assembling the segment 101 into a spherical shell shape is simplified, and
the spherical shell diaphragm 200 can be easily assembled.
[0096]
In each segment 101, since the central axis O of the polygon, which is the outer shape, and the
central axis Ob of the drive of the drive unit 232 (the tube axis of the voice coil bobbin 221)
coincide with each other, A general purpose drive unit 232 having a rotationally symmetric
shape can be used.
Further, the alignment between the movable part side and the fixed part side in the assembling
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operation can be easily and accurately performed.
[0097]
The embodiments and application examples of the present invention are not limited to the abovedescribed configuration, and may be modified without departing from the scope of the present
invention. For example, in the case where the spherical shell diaphragm 201 is formed using the
diaphragm 100 whose outer shape is a regular n-gon, when n is 4 or 5, the lengths and
directions of the respective sides conform to each other. It can be connected to a polyhedron. In
addition, when n is 6 or more, a regular polyhedron can not be formed, so when it is formed into
a spherical shell, a gap is generated, but this gap is closed by a flexible connecting member to
connect them. A spherical shell diaphragm having a substantially spherical shell shape can be
obtained. The edge 102, which is a connecting member for connecting the diaphragms 10, 10R,
and 100, is bonded to each of the diaphragms 100, 10R, and 100 using an adhesive. However,
the invention is not limited to the use of the edge 102, The diaphragms 100, 10R, and 100 may
be bonded to each other via an adhesive. In this case, it goes without saying that this adhesive
serves as a connecting member.
[0098]
As described above in detail, according to the first and second embodiments of the present
invention, the central axis O of the outer shape of the diaphragm 10 100 coincides with the tube
axis Ob of the voice coil bobbin 21 (the central axis of the drive portion 32 Since the size of the
housing 35 for supporting the diaphragm 10, 100 is sufficient, the diaphragm 10, 100 can have
a wider projection area without a shortage. Therefore, the electro-acoustic conversion efficiency
with respect to the input signal is high, and high sound pressure can be obtained even in the bass
range. In addition, since the reference direction of sound emission matches the vibration
direction, it is clear that uniform directional characteristics can be obtained in the circumferential
direction.
[0099]
It is a schematic perspective view which shows the diaphragm of 1st Example concerning this
invention. It is the top view and sectional drawing which show the diaphragm of 1st Example
concerning this invention. It is a sectional view showing an electroacoustic transducer of a 1st
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example concerning the present invention. It is sectional drawing which shows the other example
of the electroacoustic transducer of 1st Example which concerns on this invention. It is a
schematic diagram for demonstrating standing wave distribution in the conventional diaphragm.
It is a schematic diagram for demonstrating standing wave distribution in the diaphragm of 1st
Example which concerns on this invention. It is a graph which shows the frequency-sound
pressure characteristic according to the amount of eccentricity of a diaphragm. It is a typical
sectional view for explaining the shape of a diaphragm of the 1st example concerning the present
invention. It is a typical sectional view for explaining other shapes of a diaphragm of a 1st
example concerning the present invention. It is the top view and sectional drawing which show
the modification of the diaphragm of 1st Example which concerns on this invention. It is a front
view for comparing and explaining the conventional diaphragm and the diaphragm of 2nd
Example in this invention. It is a typical sectional view for explaining an electroacoustic
transducer of a 2nd example concerning the present invention. It is a developed view for
explaining a diaphragm of an application example of the present invention. It is an external view
which shows the electroacoustic transducer of the application example of this invention. It is a
perspective view for demonstrating the structure of the electroacoustic transducer of the
example of application of this invention. It is a fragmentary sectional view for explaining the
electroacoustic transducer of the example of application of the present invention. FIG. 17 is
another perspective view for explaining the structure of the electroacoustic transducer of each of
the embodiments according to the present invention. It is the front view and perspective view for
demonstrating the modification of the diaphragm of the application example of this invention. It
is a front view for demonstrating the electroacoustic transducer of the application example of
this invention.
Explanation of sign
[0100]
10, 10R, 100 diaphragm 11 central portion 12 inclined portion 12a inclined portion inner side
surface 12b inclined portion outer side surface 13 inner diameter portion 14 outer diameter
portion 15 intermediate diameter portion 21, 221 voice coil bobbin 21a cylindrical portion 21b
joint portion 22, 222 voice coil 22a Lead wire 23, 223 yoke 23a bottom 23b annular wall 24,
224 magnet 25, 225 pole piece 30 edge 31 housing 31 a hole 31 b annular frame 32, 232
driving unit 33 damper 34, 234 magnetic circuit 50, 150 electroacoustic transducer 200 , 201
ball shell diaphragm 10a, 100a diaphragm 101 segment 102 edge 103 support leg 130 base
131 frame for base 132 support base 132a mounting surface 202 assembly 235 frame 236
support D1 to D3 diameter L floor surface G0 main center (center) G1 to Gn center of gravity α
(of eccentricity) distance O3 center O4 center of curvature O, O2, O5, O12 center axis Ob (voice
coil bobbin) tube axis P0 reference plane 蛆 P13 including inner diameter Plane T1 to Tn vertex
TP1 to TPn top R, R1 curvature α distance (amount of eccentricity)
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