JPS5859697A - Plane speaker - Google Patents

Abstract

PURPOSE:To extend the reproducing frequency band of a plane speaker, by connecting a damper consisting of visco-elastic materials to the outside circumference of a diaphragm. CONSTITUTION:A magnetic circuit consists of a top plate 1, a magnet 2, and a plate 3 with a pole piece. The upper end of a voice coil bobbin 5 is connected to a plane diaphragm 6. The inside of a ring-shaped or arc-shaped damper 9 which is stuck or coated to an edge 7 and consists of visco-elastic materials represented by rubber is adhered to all of or a part of the outside circumference of the diaphragm 6, and the outside of the damper 9 is fixed to a frame 8. Consequently, the plane diaphragm 6 is supported through the damper 9 in the semifixing state by the frame 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrodynamic flat speaker in which a flat diaphragm is directly driven by a voice coil, and its purpose is to increase the high frequency limit of the flat diaphragm. The high limit frequency of a conventional flat plate speaker, in which the voice coil is directly coupled to a flat diaphragm and the outer circumference of the diaphragm is free, is the same as that of a single diaphragm. The primary resonance frequency of The reason for this is that when negative-order resonance occurs, if the node is a circular diaphragm, the area of the inside and outside of the node is equal to +t'x, so if the node is a circular diaphragm, the area of the inside and outside of the node is equal to +t' For frequency vibrations, the effective vibration area is greatly reduced, and there is a large difference (10(1)
1) occurs, and the sound with a frequency substantially higher than the primary resonance frequency is in a state where it is incorrect to say that it is not being reproduced.

In view of this point, the present invention is arranged such that the node of the -order resonance is closer to the outer circumference of the diaphragm, and also includes the -order resonance.
If the structure is designed to dampen the illusion when high-order resonance occurs, it is intended to raise the high limit frequency and widen the reproduction frequency band, and the flat diaphragm is used as a voice. In an electrodynamic slave speaker that is directly driven by a coil, a ring-shaped or arc-shaped damper made of a viscoelastic material such as rubber is bonded to part or all of the outer periphery including the edge of the flat diaphragm, and 2. The diaphragm is characterized in that the outer periphery of the diaphragm is semi-fixedly supported by a frame via the damper.

Embodiments of the present invention will be described with reference to the drawings. In FIG. 1, 1 is a top plate, 2 is a magnet, and 5 is a plate with a pole piece, which constitutes a magnetic circuit using straw. 4 is a voice coil placed in the magnetic gap formed between the pole piece and the top plate 1, and the upper end of the voice coil bobbin 5 is connected to the flat diaphragm 6! ! It doesn't match. 7 is the edge of the flat diaphragm 6, 8 is the top play)
This is a fixed IK frame.

Reference numeral 9 denotes a ring-shaped or arc-shaped damper made of a viscoelastic material, typically rubber, which is pasted or painted on the edge 7, and whose inner side is glued to the entire or part of the outer periphery of the diaphragm 6. , the outer edge is fixed to the frame 8. Therefore, the flat diaphragm 6 is semi-fixedly supported by the frame 8 via the damper 9. In FIG. 10)&C, d indicates a portion without a damper when an arc-shaped damper 9 is used. Second
The figures show examples of lumber dampers with different shapes and mounting forces. (A) is a case where the flat plate diaphragm 6 is supported from below by a ring-shaped or arc-shaped damper 9 with a square cross section, IP)
When a ring-shaped or arc-shaped damper 9 with a rectangular cross section is joined to the peripheral end face of the flat plate diaphragm 6, f → is the ring-shaped or circular arc-shaped damper 9 with a rectangular cross section and the peripheral surface of the flat plate vibration J#L6. ) and (e) are the cross-sections L
! i! The flat plate diaphragm 6 is a ring-shaped or arc-shaped damper 9.
This is the case when the outer periphery of

As mentioned above, since the outer periphery of the flat diaphragm of the present invention is supported in a semi-fixed state, when -order resonance occurs, the flat plate diaphragm of the present invention can be replaced by a conventional flat plate speaker in which the outer periphery of the flat glazed diaphragm is free-circuited. The diameter of the node is larger than that of the node, and the inner and outer areas of the node are larger than the outer area, and the drop in the sound pressure level after -th order resonance is reduced. Furthermore, since the outer periphery of the flat diaphragm is damped, dips in characteristics caused by resonance are not improved, and smooth reproduction from low frequencies to frequencies after primary resonance is possible. As a result of the experiment, as shown in Figure 6, compared to a flat-plate speaker using a conventional flat-plate diaphragm with a free outer periphery, the reproduction band can be changed by 15 to 2 times in the frequency band above the -order resonance wave number. I confirmed that it was true. Figure 5 0) shows the edge 7 of the flat diaphragm 6.
The sound pressure and frequency characteristics of the embodiment shown in FIG.
This is the sound pressure and frequency characteristics of the embodiment shown in FIG. 2 (0) in which the

In the same figure, dotted lines a and a' are the sound pressure and impedance characteristics of a flat plate speaker using a conventional flat plate diaphragm, and fa and fb are the high frequency limit frequencies of the conventional flat plate speaker and the flat plate speaker of the present invention. , and C indicates that disturbances in the impedance characteristics are damped.

As described above, the present invention can expand the reproduction frequency band of a flat speaker by the extremely simple means of joining a damper made of a viscoelastic material to the outer periphery of a diaphragm, thereby improving the quality of a simple flat speaker. It has an excellent improving effect.

[Brief explanation of drawings]

Figure 1 2 Examples of the flat speaker of the present invention, (A) is a plan view, ←) is a longitudinal side view #I & 2: Various embodiments of the damper of the present invention (A) ←)
(C)) (E) is a side sectional view thereof. No. 5 @: N> and ←) are graphs comparing the sound pressure and frequency characteristics of the flat plate speaker of the present invention and a conventional flat plate speaker.

Claims (1)

[Scope of Claims] A round or arc-shaped damper made of a viscoelastic material such as rubber is bonded to part or all of the outer periphery including the edges of the flat diaphragm, and the outer periphery of the flat diaphragm is A flat plate speaker characterized in that the wrinkled flat plate diaphragm is semi-fixedly supported by a frame via the damper, and is driven by a voice coil fitted into a magnetic gap of a magnetic circuit.