JPH0434360B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker including a ring-shaped planar diaphragm, such as a coaxial planar speaker.

As shown in FIG. 1, a conventional speaker equipped with a ring-shaped plane diaphragm has a ring-shaped plane diaphragm 1 fixed to a voice coil bobbin 6, and this diaphragm 1 is attached to a frame 3 via an edge 2 on its outer periphery. A damper 4 is interposed between the frame 3 and the voice coil bobbin 6. 5 is a voice coil wound around the lower part of the voice coil bobbin 6, 7 is a magnet disposed inside the voice coil, and 8 is a tweeter or a spacer. The frequency sound pressure characteristics of a conventional speaker with such a configuration, which is equipped with a ring-shaped flat diaphragm having an outer diameter of 10 cm and an inner diameter of 5 cm, exhibits a peak near 7 KHz, as shown by the broken line in FIG. 4. This is the fifth
This is due to mode resonance as shown in the figure, that is, secondary resonance, and its peak height reaches around 10 dB. This large peak of the second-order resonance has been one of the major drawbacks of speakers equipped with ring-shaped planar diaphragms. Furthermore, the reproduction frequency limit is regulated at this peak and remains at 7KHz, and it is desired to increase the reproduction frequency limit in the high range.

In view of this situation, it is an object of the present invention to provide a speaker equipped with a ring-shaped plane diaphragm that increases the high frequency reproduction limit frequency and suppresses the peak there.

To achieve this object, the present invention provides a ring-shaped planar diaphragm, a ring attached to the inner side of an inner circumferential cross section of the ring-shaped planar diaphragm or an inner periphery of the back surface thereof, and a ring-shaped planar diaphragm that is attached to the ring-shaped planar diaphragm. and a tweeter disposed inside a ring-shaped plane diaphragm, to provide a speaker that suppresses a second resonance mode.

Furthermore, a ring-shaped planar diaphragm, a voice coil bobbin whose upper end is located inside the inner circumferential cross-section of the ring-shaped planar diaphragm, and a cone-shaped structure that connects the substantially central portion of the ring-shaped planar diaphragm and the voice coil bobbin. A similar effect can be obtained with a configuration including a viscoelastic material sandwiched and attached between the upper end of the voice coil bobbin and the ring-shaped plane diaphragm, and a tweeter arranged inside the ring-shaped plane diaphragm. The present invention also provides such a speaker.

Next, embodiments of the present invention will be described based on the drawings. Components that are substantially the same as those described in FIG. 1 are designated by the same reference numerals and their description will be omitted. In the embodiment shown in FIG.
are attached, and a viscoelastic material 9 is sandwiched and adhered therebetween. The ring 10 may be attached to the inner circumference of the back surface of the ring-shaped flat diaphragm 1.

In the embodiment shown in FIG. 3, the voice coil bobbin 6 extends to the inside of the inner periphery of the ring-shaped flat diaphragm 1, and is located between the inside of the inner periphery cross section of the ring-shaped flat diaphragm 1 and the upper end of the voice coil bobbin 6. A viscoelastic material 9 is sandwiched between and adhered to. A cone-shaped structure 11 extends from the voice coil bobbin 6 and is connected to a substantially central portion of the ring-shaped flat diaphragm 1 to transmit vibrations generated by the voice coil 5.

When the frequency sound pressure characteristics of the speakers of each of these examples were investigated, characteristics as shown by the solid line in FIG. 4 were generally obtained. That is, by adopting the above configuration, the second-order resonance mode as shown in FIG. 5 is suppressed, the reproduction frequency limit is increased to 10 KHz, and the peak is also reduced to several dB or less.

As is clear from the above description, according to the first aspect of the present invention, a ring to which a viscoelastic material is attached is attached to the inner side of the cross section of the ring-shaped plane diaphragm or the inner circumference of the back surface. As a result, the mass of the ring and the viscosity of the viscoelastic material combine to damp the vibration at the innermost circumference of the second resonance mode whose amplitude is at the inner circumference of the ring-shaped plane diaphragm.
The next resonance mode is suppressed.

According to the present invention shown in FIG. 2, a cone-shaped structure is provided that connects a ring-shaped plane diaphragm and a voice coil bobbin, and a viscous By adopting a structure in which an elastic material is interposed, the viscoelastic material is sandwiched between the voice coil bobbin and the ring-shaped plane diaphragm, and the viscosity of the viscoelastic material causes the inner circumference of the ring-shaped plane diaphragm to vary in amplitude. Since the vibration at the innermost circumference of the second-order resonance mode, which is the antinode, is damped, the second-order resonance mode is suppressed.

In short, in any of the configurations of the present invention, the second resonance mode of the ring-shaped plane diaphragm itself is suppressed, the peak of the second resonance in the reproduction frequency band is suppressed, and the reproduction frequency band is increased. It has the unique effect of being

[Brief explanation of drawings]

Fig. 1 is a sectional view of the conventional example, Figs. 2 and 3 are sectional views of the embodiment of the present invention, Fig. 4 is a graph showing the frequency sound pressure characteristics, and Fig. 5 is the second order of the diaphragm. It is an explanatory view showing resonance. 1 is a ring-shaped plane diaphragm, 5 is a voice coil,
6 is a voice coil bobbin, 9 is a viscoelastic material, 10
is a ring, and 11 is a cone-shaped structure.

Claims (1)

[Scope of Claims] 1. A ring-shaped planar diaphragm 1, a ring 10 attached to the inside of the inner cross-section of the ring-shaped planar diaphragm 1 or the inner periphery of the back surface, and the ring 10 and the ring-shaped planar diaphragm. 1, and a tweeter 8 disposed inside the ring-shaped plane diaphragm 1. 2. A ring-shaped planar diaphragm 1, a voice coil bobbin 6 whose upper end is located inside the inner peripheral cross section of the ring-shaped planar diaphragm 1, and a substantially central portion of the ring-shaped planar diaphragm 1 and the voice coil bobbin 6. a cone-shaped structure 11 that connects the voice coil bobbin 6 to the ring-shaped plane diaphragm 1; 1. A speaker comprising: a tweeter 8 arranged at the top of the tweeter 8;