JP3245074B2 - Double dome diaphragm and speaker using it - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double dome diaphragm capable of increasing a reproduction frequency in a low frequency range,
It relates to a speaker using it.

[0002]

2. Description of the Related Art A low frequency resonance frequency f _{0 of a} conventional speaker.
In order to increase the reproduction frequency in the low frequency range by lowering
A method of thinning the diaphragm has been adopted.

[0003]

However, even though the bass resonance frequency f ₀ can be reduced by making the diaphragm thin, it is not possible to make the diaphragm thinner than a certain level because the thinner the diaphragm, the lower the input resistance. It was possible. As shown in FIG. 4, the bass resonance frequency f ₀ of a general conventional speaker is 4 if the aperture is 5 cm (50 mm).
It is around 00 Hz.

The present invention has been made in view of the above circumstances, and provides a double dome diaphragm capable of lowering the low-frequency resonance frequency f ₀ and broadening the reproduction frequency in a low frequency range, and a speaker using the same. It is intended to provide.

[0005]

A double dome diaphragm according to the present invention comprises a first diaphragm attached to a frame, and a second diaphragm attached to the first diaphragm. The first diaphragm has a roll edge at a peripheral edge portion, and the second diaphragm has a first diaphragm.
The same material as that of the moving plate is used, and is attached to a portion other than the edge portion of the first diaphragm.

Further, the second diaphragm is thicker than the first diaphragm.

Furthermore, the peripheral portion of the second diaphragm is configured not to be along the edge of the first diaphragm.

On the other hand, a speaker according to the present invention uses the double dome diaphragm.

[0009]

1 is a schematic sectional view of a speaker using a double dome diaphragm according to an embodiment of the present invention, and FIG. 2 is a diagram showing a speaker using the double dome diaphragm according to the embodiment of the present invention. FIG. 3 is a diagram illustrating a frequency characteristic of a speaker, and FIG. 3 is an explanatory diagram of a measurement method when measuring a frequency characteristic of a speaker using the double dome diaphragm according to the embodiment of the present invention, and a schematic front view of a baffle plate used for the measurement. FIG.

A speaker using a double dome diaphragm according to an embodiment of the present invention includes a frame 200 and a double dome diaphragm 10 attached to the frame 200.
0, a voice coil 300 attached to the back side of the double dome diaphragm 100, a magnet 400 attached to the center of the frame 200, and a pole 500 attached to the top of the magnet 400. .

The voice coil 300 is formed in a cylindrical shape and fits into a gap between the pole 500 and the frame 200.

The double dome diaphragm 100 is composed of a first diaphragm 110 and a second diaphragm 120. The first diaphragm 110 has a circular shape in a plan view, and has a first dome portion 111 that is convex toward the surface with the center point O as a center. Outside the first dome portion 111, a second dome portion 112 that is convex toward the front surface side is formed. The second dome 112 has a substantially donut shape so as to surround the first dome 111.

The peripheral edge 113 of the first diaphragm 110 is a roll edge. The roll edge refers to an edge formed in a roll shape or a curved shape in a sectional view. The edge portion 113 includes a bent portion 113A that is sharply bent downward from the periphery of the second dome portion 112, a curved surface portion 113B that is connected to the bent portion 113A and that is convex downward, and a curved surface portion 113B. And a mounting portion 113C extending in the outer horizontal direction following the portion 113B.

The curved portion 113B has a substantially J-shape as shown in FIG.

The first diaphragm 110 is made of PET resin (polyethylene terephthalate resin). If the first diaphragm 110 has a diameter of 50 mm, a thickness of 25 μm is used.

On the other hand, the second diaphragm 120 is provided on the back side of the first diaphragm 110 at the edge portion 1 of the first diaphragm 110.
It is stuck on parts other than 13. That is, this second
The diaphragm 120 is attached to the back surface of the first dome portion 111 and the second dome portion 112 with an adhesive.
In addition, the second diaphragm 120 is connected to the first diaphragm 110
Of the first dome portion 111 and the second dome portion 112. Therefore, the second diaphragm 120 is connected to the first diaphragm 120.
The diaphragm 110 is stuck in a state of close contact.

The second diaphragm 120 is thicker than the first diaphragm 110. That is, the first diaphragm 110 is thinner than the second diaphragm 120.
For example, if the diameter is 50 mm as described above, the thickness of the second diaphragm 120 is 188 μm.

The second diaphragm 120 is made of PET resin, like the first diaphragm 110. In addition, P constituting the first diaphragm 110 and the second diaphragm 120
The ET resin used is 1.40 (g / cm ³ ).

The first diaphragm 110 is connected to the second diaphragm 120
Is applied, the rigidity of the entire double dome diaphragm 100 is improved, and the mass of the double dome diaphragm 100 is increased.

The bass resonance frequency f ₀ is such that the effective mass of the vibration system is m ₀ (gr), and the stiffness of the vibration supporting portion is s ₀ (d
yne / cm), 1 / 2π (s ₀ / m ₀ ) ^1/2
Given by That is, the bass resonance frequency f ₀ is equal to the effective mass of the vibration system (the first diaphragm 110 and the second diaphragm 120
(The sum of the masses of the vibration supporting portions) increases, and decreases when the stiffness of the vibration supporting portion is reduced.

The thus configured double dome diaphragm 100 has a first dome portion 111 and a second dome portion 1.
The voice coil 300 is attached to the joint 114 between the two, i.e., the back side of the concave portion in an arc shape.
Further, the edge portion 11 of the double dome diaphragm 100
The third mounting portion 113C is mounted on a diaphragm mounting portion 210 formed on the frame 200 with an adhesive.

The frequency characteristics of a speaker having a diameter of 50 mm using the double dome diaphragm 100 constructed as described above were measured by the measuring method shown in FIG. As a result of the measurement, as shown in FIG. 2, a bass resonance frequency f ₀ of 200 Hz was obtained.

[0023] This measurement, attaching the speaker to the center of 70cm square of the baffle plate 6 00 (see FIG. 3 (B)), carried out by spaced and opposed microphone and 50cm inside silent chamber (Fig. 3 (A)). The input in this case is 0.1W.

The reason why such a low bass resonance frequency f ₀ can be obtained is that the rigidity of the entire double dome diaphragm 100 is increased by attaching the second diaphragm 120 to the first diaphragm 110. This is attributable to the fact that the mass has been increased together with the improvement. The edge portion 113 is formed only of the first diaphragm 111 which is thinner than the second diaphragm 112 and is a roll edge.
13 that is, the rigidity of the vibration
₀ (stiffness of the vibration supporting portion) was reduced.

[0025]

The double dome diaphragm according to the present invention includes a first diaphragm attached to a frame, and a second diaphragm attached to the first diaphragm. The first diaphragm has a roll edge at a peripheral edge portion, and the second diaphragm has the same material as the first diaphragm.
Is used and is attached to a portion other than the edge portion of the diaphragm .

By attaching the second diaphragm to the first diaphragm, the rigidity of the whole diaphragm is improved,
Since the mass is increased, the bass resonance frequency f ₀ can be made smaller than that of the conventional one. Further, the rigidity is lowered because the edge portion is constituted of only the first diaphragm, the stiffness of the vibration support portion is reduced, contributing to a reduction in bass resonance frequency f _0. Further, since the edge portion is configured as a roll edge, it can withstand a large amplitude. That is, it has become possible to withstand a larger input.

Further, since the second diaphragm is thicker than the first diaphragm, when the second diaphragm is attached to the first diaphragm, the second diaphragm becomes the first diaphragm. Compared with the case where the thickness is equal to or less than the thickness of the plate, the rigidity of the entire double dome diaphragm can be further improved, and the mass can be significantly increased. The improvement of the rigidity and the increase of the mass of the entire double dome diaphragm is due to the low resonance frequency f.
_{Since 0} is reduced, this configuration makes it possible to reduce the bass resonance frequency f ₀ more effectively. In addition, since the edge portion is formed only of the thinner first diaphragm, the rigidity of the vibration supporting portion is reduced, the stiffness of the vibration supporting portion is reduced, and the low sound resonance frequency f ₀ can be reduced. .

Further, since the peripheral portion of the second diaphragm is configured not to be along the edge of the first diaphragm, the double dome diaphragm is supported only by the edge. . Therefore, since the movement of the edge portion is not hindered by the second diaphragm, the roll edge can sufficiently perform its function.

On the other hand, the speaker according to the present invention, since have use the double dome diaphragm, bass resonance frequency f
₀ can be lowered. For example, conventional 50m diameter
m, the bass resonance frequency f ₀ is 400H
This speaker has a caliber of 50m
If m, the bass resonance frequency f ₀ can be reduced to about 200 Hz. Therefore, since the low-frequency reproduction frequency has been widened, powerful low-frequency sound reproduction has become possible, and it has become possible to use it as a woofer.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a speaker using a double dome diaphragm according to an embodiment of the present invention.

FIG. 2 is a frequency characteristic diagram of a speaker using the double dome diaphragm according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram of a measuring method when measuring the frequency characteristics of a speaker using the double dome diaphragm according to the embodiment of the present invention, and a schematic front view of a baffle plate used for the measurement.

FIG. 4 is a graph showing the relationship between the aperture of a conventional speaker and the bass resonance frequency.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 double dome diaphragm 110 first diaphragm 113 edge portion 120 second diaphragm

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04R 7/02 H04R 7/14

Claims (4)

(57) [Claims] A first diaphragm attached to a frame; and a second diaphragm attached to the first diaphragm, wherein the first diaphragm has a peripheral edge. Part is a roll edge, and the second diaphragm is a first diaphragm.
A double dome diaphragm which is made of the same material as the moving plate and is attached to a portion other than an edge portion of the first diaphragm. 2. The double dome diaphragm according to claim 1, wherein the second diaphragm is thicker than the first diaphragm. 3. The double dome diaphragm according to claim 1, wherein a peripheral portion of the second diaphragm does not extend along an edge portion of the first diaphragm. 4. A speaker using the double dome diaphragm according to claim 1, 2 or 3.