JPH0241988Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a flat speaker having a flat diaphragm to which a center cap is attached.

BACKGROUND ART AND PROBLEMS In recent years, flat speaker units having flat diaphragms have been frequently used as speaker units constituting speaker systems.

This is because honeycomb cores and hard foamed polymer materials have become available at low cost as diaphragm materials that are lighter and more rigid than before, so by using these materials to construct a flat diaphragm, it is possible to It is now possible to eliminate the cavity effect, which has been a problem with type diaphragms, without lowering the piston vibration area.
This is because it has become possible to obtain high-quality reproduced sound over a wider reproduction frequency band.

Conventionally, this type of flat-plate speaker has a first speaker that can be manufactured by the same method as a conventional cone-type speaker, for example.
There are configurations as shown in FIG. 2 and FIG.

That is, plate 2 with center pole 1
A frame 6 is connected to a magnetic circuit 5 constructed by incorporating a ring-shaped magnet 3 and an upper plate 4 on the top, and a free edge 9 connected to the peripheral edge of a gasket 7 and a flat diaphragm 8 is attached to the peripheral edge of the frame 6. A voice coil bobbin 10 is connected to the lower surface of the flat diaphragm 8 via a joining ring 16, and an intermediate portion of the voice coil bobbin 10 is connected to a damper 1.
2 and wound around the lower part of the voice coil bobbin 10, the voice coil 11 is fitted into the magnetic gap 13 of the magnetic circuit 5 without eccentricity.

Further, as shown in FIG. 2, this flat plate diaphragm 8 has a skin material 8b bonded to at least the surface of a honeycomb core 8a using a film adhesive or the like. Note that a skin material 8c may be similarly bonded to the back surface. A jig extraction hole 14 having a diameter larger than the diameter of the voice coil bobbin 10 is formed in the center of the flat diaphragm 8 in order to take out the jig for positioning the voice coil bobbin 10 at a predetermined position within the gap 13. A center cap 15 made of a thin flat plate of aluminum is attached to the surface of the flat diaphragm 8 so as to close the opening.

Furthermore, since this center cap 15 is a thin flat plate, a damping material 17 (for example, a damping material such as 2 mm thick foamed neoprene sponge, urethane, felt, rubber, etc.) is used to prevent the occurrence of so-called rattling noise at the resonance point. , this center cap 1
It is normal to stick it on the back side of 5.

However, the brake material 1 is attached to the center cap 15.
If 7 is attached, there is a drawback that it leads to a decrease in high frequency range in the sound quality and the frequency characteristics of the speaker.

By the way, as another conventional example, there is also a flat plate speaker having a configuration as shown in FIG. 3, which is assembled and manufactured using a special jig.

In this flat speaker, voice coil bobbin 1
Since the flat diaphragm 8 is manufactured using a special jig 20 that can be temporarily fixed with the diaphragm 0 positioned at a predetermined position within the gap 13 and then broken off and removed after assembly, no openings or the like are made in the flat diaphragm 8. .

When such a flat plate diaphragm 8 is used, since the flat plate diaphragm 8 is a single flat plate diaphragm, its frequency band is limited, and the frequency band is too narrow to be used as a full-range speaker. There was a drawback.

Purpose of the invention In view of the above points, the present invention provides a center cap with a structure that can improve frequency characteristics on a flat diaphragm.
The purpose is to improve the frequency characteristics and sound quality of flat speakers.

Summary of the invention The flat speaker of the invention improves the frequency characteristics and sound quality by configuring a dome-shaped part in the center cap that closes the hole for extracting the jig in the flat diaphragm to improve the frequency characteristics. .

Embodiments Hereinafter, embodiments of the flat speaker of the present invention will be described with reference to FIGS. 4 to 9. Note that in FIGS. 4 to 9, parts corresponding to those in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

4 to 6 show a first embodiment, in which a center cap 15 having a rectangular planar shape and a dome-shaped portion 22 in the center is used for extracting a jig for a flat diaphragm 8. It is attached to the surface of the flat diaphragm 8 so as to close the opening 14.

That is, in order to close the circular jig removal opening 14 of the flat diaphragm 8, a thin aluminum plate is formed into a dome shape with four smooth arcuate ridges that radiate toward the four corners of the rectangle. A center cap 15 having a dome-shaped part 22 formed to bulge is attached to the surface of a flat diaphragm 8.

In the above-mentioned configuration, the dome-shaped portion 22 of the center cap 15 is convex from the surface of the flat diaphragm 8, but the square dome-shaped portion 22 of the center cap 15 is It may be configured to be concave from the surface of the flat diaphragm 8.

Furthermore, not only the square dome-shaped part 22,
Polygonal dome-shaped part 2 such as a triangle or pentagon
In addition, the apex of the dome-shaped portion 22 may be eccentric from the center of the center cap 15 by a required amount.

In this way, if the dome-shaped portion 22 is formed on the center cap 15, which has a rectangular planar shape, the distance from the center of the center cap 15 to its periphery will not be uniformly determined, but will change. Variations will also occur in the resonance frequency of the 15 itself. Therefore, the frequency characteristics in the high range of the flat speaker are improved.

Note that by configuring the center cap 15 with a dome-shaped portion 22 such as a square, the center cap 1
5 has structural rigidity due to the dome structure, and it is possible to prevent the occurrence of a rattling sound as would be the case when it is formed as a flat plate. Therefore, there is no need to attach damping material.

Furthermore, it is possible to reproduce frequency bands that cannot be reproduced by the flat diaphragm 8 alone using the center cap 15 formed in the dome-shaped portion 22, such as a square. Compared to a device without a diaphragm, the reproduction frequency band can be widened to a wide frequency band including the band of the flat diaphragm 8 and the band of the center cap 15, and the sound quality can be improved.

To explain this specifically with the diagram shown in Figure 8, the diagram has frequency (Hz) on the horizontal axis and decibels (db) on the vertical axis, and the curve shown by solid line A is the square in this example. This is a characteristic curve of a flat speaker equipped with a center cap 15 having a dome-shaped portion 22, and the one shown by dotted line B in the diagram is the characteristic curve of a flat speaker equipped with a conventional flat center cap 15.

As is clear from this, the characteristic curve A of the flat speaker of this example is relatively flat, and a good effect can be recognized in that it extends even in the high range.

Furthermore, in the flat speaker of this example, the flat plate diaphragm 8
Since a jig extraction hole 14 is provided in order to take out the jig for positioning the voice coil bobbin 10 at a predetermined position within the gap 13, the special jig can be removed using the same manufacturing means as conventional cone-shaped speakers. Another advantage is that it can be easily manufactured without using other materials.

Next, a second embodiment of the present invention will be described with reference to FIGS. 7 and 9. The flat speaker of this example has a center cap 15 in which a spherical dome-shaped portion 22 is formed on a flat diaphragm 8.
That is, the center cap 15 has a dome-shaped portion 22 formed to bulge into a spherical dome shape that can be easily formed and processed from a thin aluminum plate so as to close the circular jig extraction opening 14 of the flat diaphragm 8. It is configured by being attached to the surface of the flat diaphragm 8. Note that the above-mentioned center cap 1
The spherical dome-shaped portion 22 of the center cap is configured to be concave from the surface of the flat diaphragm 8. may be configured.

With this configuration, the center cap 15 can be provided with stronger structural rigidity, and the reproduction frequency band of the center cap 15 can be widened in addition to the frequency band of the flat diaphragm 8.

This will be concretely explained using the chart shown in FIG. 9, in which the horizontal axis shows frequency (Hz) and the vertical axis shows decibels (db). The curve shown by the solid line A is the characteristic curve of the flat speaker equipped with the center cap 15 which constitutes the square dome-shaped part 22 of the first embodiment, and the curve shown by the dotted line C in the diagram is the characteristic curve of the flat speaker according to the first embodiment. This is a characteristic curve of a flat speaker provided with a center cap 15 having a spherical dome-shaped portion 22 according to the second embodiment.

As can be understood from this, the characteristic curve C of the flat speaker of this example does not have a flat frequency characteristic like the curve A of the first embodiment, but it is similar to the curve B of the conventional flat speaker shown in FIG. By comparison, it can be seen that the frequency characteristics are partially flattened and extended even in the high range, which is a good effect.

It should be noted that other than what has been explained above is the same as the first embodiment described above, so the explanation thereof will be omitted.

Effects of the invention According to the flat speaker of the present invention, the center cap that closes the opening for extracting the jig in the flat diaphragm is made into a dome shape that can improve the frequency characteristics, so even if the damping material is omitted, the center cap will not be damaged. It is possible to prevent the generation of sound, and furthermore, the reproduction frequency band of the center cap is added to the reproduction frequency band of the flat plate diaphragm, thereby making it possible to widen the reproduction frequency band, thereby improving frequency characteristics and sound quality. In addition, since the planar shape of the center cap is square, the resonance frequency of the center cap is not constant, so there is no risk that the reproduction frequency characteristics of the speaker will deteriorate due to the presence of the center cap, and good sound quality can be reproduced. You can get the sound.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an example of a conventional flat-plate speaker, FIG. 2 is a perspective view of the flat-plate diaphragm, and FIG. 3 is a longitudinal cross-sectional view showing another example of the conventional flat-plate speaker.
FIG. 4 is a vertical cross-sectional view showing the first embodiment of the flat plate speaker of the present invention, FIG. 5 is a plan view thereof, FIG. 6 is a perspective view showing the flat plate diaphragm, and FIG. 7 is a flat plate speaker of the present invention. 8 and 9 are curve diagrams for explaining the frequency characteristics of the flat speaker of the present invention, respectively. 8 is a flat plate diaphragm, 14 is an opening for extracting a jig,
15 is a center cap, and 22 is a dome-shaped portion.

Claims (1)

[Scope of Claim for Utility Model Registration] A center cap having a rectangular planar shape and a dome-shaped portion in the center is provided, and the center cap is attached to the flat plate so as to close the opening for extracting the jig of the flat plate diaphragm. A flat speaker that is attached to the surface of a diaphragm.