JPS60167596A - Plate speaker - Google Patents

Abstract

PURPOSE:To prevent the generation of a peak dip on a sound pressure frequency characteristic by making the shape of adhered part of a plate diaphragm constituted of a sandwitch construction ellipitcal shape which inscribs or circumscribes a joint diameter of a large diameter or small one of the linear resonance joint diameter and the quadratic one, and providing a flat part to a transmitting member. CONSTITUTION:Assuming that a diameter of a plate diaphragm 11 is (a), the linear resonance joint diameter 15 goes to 0.68a, and out of the quadratic resoncance diameters, the larger one 16 and the smaller one 16' go to 0.84a and 0.39a, respectively. When drive force is impressed to a transmitting member 14 from a voice coil bobbin 12, the drive force is effectively transmitted in the larger or smaller diameter of the transmitting member 14 as it is and acts to the joint diameter 15 and 16, but except said directions the drive force is rejected by flat parts 14c, 14d, 14e and 14f, which are provided on a slop of the transmitting member 14; therefore the band reproduction up to the cubic resonance frequency can be realized, and peak dips in the linear resonance frequency and the quadratic resonance frequency are eleminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a flat plate speaker, and in particular to a flat plate speaker in which a sandwich structure formed by bonding surface materials to both sides of a core material is used as a circular flat plate diaphragm, and this flat plate diaphragm This invention relates to a flat plate speaker configured to be driven via a transmission member provided between a node generated in a flat plate diaphragm and a voice coil bobbin.

Conventional configurations and their problems Normally, it is ideal for the diaphragm of a speaker to capture the piston over the frequency band used. For example, if the diaphragm deforms during vibration or split vibration occurs, the sound This deteriorates the frequency characteristics, distortion rate, phase characteristics, etc., and impedes high-fidelity reproduction. In order to solve these problems, a multi-plate peristaltic plate using a honeycomb sandwich structure or the like has been adopted in recent years. By the way, many Seni speakers use a so-called node drive method that drives a node pattern at the resonance frequency of the diaphragm via the voice coil bobbin or transmission member, cancels out the resonance frequency, and increases the reproduction band to near the next resonance frequency. It is often used. In particular, in a speaker using a circular flat diaphragm, the nodal pattern of the primary resonance is one circular mode, and the secondary resonance is a double concentric circular mode. Therefore, in general, the voice coil bobbin diameter or the upper end diameter of the conical transmission member is made to match the nodal circle diameter to increase the reproduction band to near the second resonance frequency, but this is not suitable for a wideband reproduction speaker. Not. In addition, there is a device in which both the large or small secondary resonance nodal diameter and the secondary resonance nodal diameter are driven by an elliptical transmission member to achieve a wide band. However, since the transmission member drives the part other than the nodal circle diameter,
The reality is that peak dips occur in the sound pressure frequency characteristics, making it impossible to achieve flat broadband reproduction.

Hereinafter, the conventional example will be explained based on FIGS. 1 and 2. That is, (1) is a circular flat plate diaphragm made of a honeycomb sandwich structure, (2) is a cylindrical voice coil bobbin around which the voice coil (3) is wound, and (4) is the voice coil (3). This is a transmission member that transmits the generated driving force to the flat plate diaphragm (1). The upper end of the transmission member (4) has an elliptical fixed portion (4) that is in and out of contact with the large diameter (small diameter (may be 5)) (5) of the secondary resonance circle diameter and the secondary resonance nodal diameter (6).
a) and is fixed to the flat diaphragm (1), and the other end is a cylindrical fixed part (41) fixed to the rim of the voice coil bobbin (2). By the way, the node driving method is achieved by driving only the resonant node circle diameter of the diaphragm.
The purpose is to flatten the resonance frequency by eliminating its peak dip, but in the case of the conventional example described above, the parts other than the major and minor diameter parts of the ellipse drive the antinodes of other vibration modes. B. The IIX power of the voice coil does not effectively act on the nodal diameter of the diaphragm, resulting in a large peak dip in the sound pressure frequency characteristics.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a flat plate diaphragm that eliminates the drawbacks of the above-mentioned conventional examples.

Structure of the Invention In order to achieve the above-mentioned object, the flat plate speaker of the present invention is a sandwich made by bonding a circular flat plate diaphragm with a surface material made of a thin film such as aluminum or mica on both sides of a core material such as a honeycomb core or expanded polystyrene. A transmission member that transmits the driving force from the cylindrical voice coil bobbin is fixed to the flat diaphragm, and the shape of the portion of the transmission section that is fixed to the flat diaphragm is set to the diameter of the first resonance node. and an elliptical or polygonal shape that is in and out of contact with the large diameter or small diameter of the secondary resonance nodal circle, and a flat part is provided in the part other than the part that is fixed to the nodal diameter of the transmission member. It is.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. (11) is a circular flat plate diaphragm, which uses a sandwich structure in which a surface material made of a thin film such as aluminum or mica is adhered to both sides of a core material such as a honeycomb core or expanded polystyrene. The opening is a cylindrical voice coil bobbin around which voice coil ~ II is wound, α41 is the driving force generated by the above-mentioned voice coil α3NC, and the above-mentioned flat plate diaphragm til
lK: A transmitting member that transmits data.By the way, if the diameter of the -th order resonance nodal circle and the diameter of the second order resonance nodal circle generated in the flat plate diaphragm tll+ are illustrated, they are as shown by the dashed line in FIG. 3. That is, if the diameter of the flat diaphragm till is a, then the -th
The diameter of the next resonant nodal circle α is 0.68&, and the diameter of the larger nodal circle (referred to as the large diameter) among the secondary resonance nodal circle diameters is 0.843.The diameter of the smaller nodal circle is 0.843. (referred to as the small diameter) (
16 becomes 0.39a. The upper end of the transmission member α is connected to the large diameter of the secondary resonance nodal circle (for example, the small diameter (16 is also acceptable) (141!L), and the lower end is fixed to the voice coil bobbin α2! (cylindrical fixed part (F,
ab), and furthermore, there is a flat part (14
0)(14d)(14e)(]4f) are formed.

According to the above configuration, when the driving force is applied to the transmission member 04 from the voice coil bobbin diameter force, the driving force is effectively transmitted as it is in the long and short axis direction of the transmission member 0 station, and the nodal circle diameter am 1161 of both However, in other directions, the flat portions (x4c) (x4d) (14e) (x4f) provided on the sloped portion of the transmission member tJ4 prevent the transmission of the driving force, resulting in third-order resonance. It is possible to achieve band reproduction up to the frequency, and also to eliminate peak dips at the first and second resonance frequencies. In other words, it is possible to realize a circular flat speaker having a wide band and flat sound pressure frequency characteristics.

Incidentally, in the above-mentioned embodiment, the upper end shape of the transmission member that touches the inner and outer diameters of the large and small nodal circles of the circular flat plate diaphragm is elliptical, but as shown in FIG. 5, it may be polygonal.

Effects of the Invention According to the above-described configuration of the present invention, when driving force is applied from the voice coil bobbin to the transmission member, the driving force is effectively transmitted as it is in the long and short axis directions of the transmission member, and the first-order and second-order resonances are generated. It acts on both nodal diameters, but in other directions, the flat portion prevents the transmission of driving force.
Achieving an excellent flat plate speaker that can eliminate peak dips at the 1st and 2nd order resonance frequencies of the circular mode of a flat plate diaphragm and has flat sound pressure frequency characteristics up to the vicinity of the 3rd order resonance frequency. can be achieved.

[Brief explanation of drawings]

1 and 2 show a conventional example. FIG. 1 is a rear view, FIG. 2 is a side view at a position corresponding to the AOB arrow in FIG. 3 shows a rear view, FIG. 4 shows a side view at a position corresponding to the AOB arrow in FIG. 3, and FIGS. 5 and 6 show other embodiments. 5 is a rear view of the transmission member, and FIG. 6 is a side view at a position corresponding to the AOB arrow in FIG. 5. (II)...Flat plate diaphragm, i+21...Voice coil bobbin, 0 (to)...Voice coil, α(1)...
・Transmission member, (140) to (14f)...flat part, α
ω... 1st-order resonance nodal circle diameter, 0@(i6... 2nd-order resonance nodal circle diameter agent Yoshihiro Morimoto Figure 2 Figure 1B Figure 4/l Figure 3B Figure 6Figure 5

Claims (1)

[Claims] L A sandwich structure consisting of a circular flat diaphragm with a surface material made of a thin film such as aluminum or mica adhered to both sides of a core material such as a honeycomb core or expanded polystyrene, and the above flat diaphragm K and a cylindrical voice coil bobbin. A transmission member that transmits the driving force from is fixed, and the shape of the fixed portion of the transmission member to the flat plate diaphragm is set to a nodal circle with a larger or smaller diameter of the primary resonance nodal circle diameter and the secondary resonance nodal circle diameter. A flat plate speaker having an elliptical shape or a polygonal shape that is in and out of contact with the diameter, and having a flat portion in a portion other than the portion fixed to the nodal diameter of the transmission member.