JPS58153494A - Speaker diaphragm - Google Patents

Abstract

PURPOSE:To improve the characteristics of a speaker diaphragm, by folding zigzag a rectangular plate-like body to contract the surface of one side and expand the other side to obtain a circular skelton part, adhering a surface material to both sides of the skelton, and varying the folding pitch toward the cirfumference of the skelton. CONSTITUTION:A rectangular plate-like body 1 is folded zigzag. Thus the surface 1A of one side of the plate 1 is contracted to form an inner circumference surface, and the surface 1B of the other side is expanded to form a circular body. At the same time, the folding pitch is varied toward the circumference of the circular body. A surface material 2 is adhered to both sides of a circular skelton member 1. The rough pitch part of the member 1 has small rigidity, and the node gets close to the center with the primary resonance frequency. On the contrary, the rigidity is shown by a curve (a) for the dense pitch part. As a result, the flat characteristics of reproduction are obtained at a high frequency band for a speaker diaphragm.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flat speaker diaphragm, and its object is to provide a speaker diaphragm that is lightweight and has high rigidity.

In general, most speaker diaphragms are made by paper-molding a valve, and the diaphragm has a cone shape.

As a result, there is a phase difference between the center of the cone and the outer periphery due to the difference in the position of the sound source, and the resonance of the air within the cone makes it difficult to obtain flat sound pressure frequency characteristics. In contrast to cracks, a flat plate speaker with a flat diaphragm and aligned sound sources is advantageous in flattening the frequency response without the front chamber effect seen in cone speakers. In the case of a flat plate diaphragm, when conventional paper was used, the rigidity against bending was low, splitting vibrations were likely to occur at low frequencies, and flat characteristics could not be obtained over a wide band. On the other hand, there are examples in which polymeric foams such as expanded polystyrene have been used as flat diaphragms, but these also have low rigidity and are not suitable as diaphragms. Therefore, a flat plate diaphragm using a Santoi-chi structure is considered, which is lightweight and has high bending rigidity. In order to realize these, in recent years, a planar diaphragm using a non-nicam sandwich structure or the like has been adopted. Here, if a so-called nodal circle drive method is used, in which the voice coil is bonded and driven at the nodal position at the first resonance frequency of the plane diaphragm, the first resonance is canceled out, so f
h (high frequency limit) can be significantly increased.

However, when the nodal drive method is used, there is a phenomenon in which the sound pressure peak at FLL becomes much sharper than that of a cone paper speaker. This is due to the fact that although the rigidity of the flat diaphragm is greater than that of cone paper, the internal loss is extremely small. There is a problem in that the thicker the sound pressure peak at fh, the narrower the usable flat frequency band becomes, making it difficult to design a speaker system.

The present invention eliminates these drawbacks and flattens the sound pressure characteristics in the high range, thereby realizing high performance of the syspee force. By intentionally causing variations, it appears to be multi-point drive, and is configured to reduce the resonance peak at fh.

Hereinafter, the speaker diaphragm of the present invention will be explained with reference to drawings of embodiments.

FIG. 1 shows an embodiment of a speaker diaphragm according to the present invention. In the figure, 1 is a current skeleton member whose skeleton density in the circumferential direction is changed, and 2 is an annular skeleton member 1. Surface material glued on both sides. As shown in Fig. 2, the annular skeleton member 1 is made by bending a long plate-like body while changing the pitch. It is obtained by expanding the frame member 1 into an annular shape so that the outer circumferential edge thereof is formed, and bonding both end surfaces of the skeleton member 1. The frame member 1 formed in an annular shape in this manner is densely and densely arranged in the circumferential direction, and when the surface material 2 is adhered to both surfaces of the frame member 1, the rigidity in the circumferential direction changes. In other words, the stiffness of the part where the skeleton members 1 are sparse is small, and the node at the primary resonance frequency is closer to the center, and conversely, the stiffness of the part where the skeleton member 1 is dense is large, and the node at the primary resonance frequency is closer to the center. is close to the outer periphery. Here, in the sandwich structure in which the surface material 2 is pasted on both sides of the annular skeleton member 1 described above, the dense parts of the annular skeleton member 1 are located at every ⅛ position in the circumferential direction, and the The denser parts are located between the denser parts. Therefore, the overall nodal circular shape is wavy as shown by the solid line a in FIG. On the other hand, when the skeleton member 1 is homogeneous in the circumferential direction, the nodal circular shape becomes a perfect circle as shown by the dashed dotted line in FIG.

Specifically, a special paper with a density of 0.8, a thickness of Q, and an IIB made by resin-processing kraft paper was used as the frame member 1, and an aluminum foil with a thickness of 60 μm was used as the surface material 2. In this way, the thickness was 6U and the outer diameter was 190m.
Figure 3 shows the sound pressure frequency characteristics when a 1B diaphragm is made and used as a speaker with a diameter of 26 sub-diaphragms. In Figure 3, a
1 shows the characteristics according to this example, and b shows the characteristics when the skeleton member is homogeneous in the circumferential direction for comparison. As can be seen from FIG. 3, according to this embodiment, the resonance peak at fll is suppressed, and a speaker having flatter high-frequency characteristics can be obtained.

As described above in detail, according to the present invention, a skeleton member formed by bending a rectangular plate-shaped body in a zigzag shape is shaped into an annular shape such that one side thereof is the inner circumferential surface and the other side thereof is the outer circumferential surface. expanded to
It consists of a sandwich structure in which surface materials are adhered to both sides of this annular skeleton member, and the skeleton density in the circumferential direction is changed by changing the bending distance of the annular skeleton member. Therefore, the resonance peak at fh is suppressed, and it has the advantage of being able to obtain flatter high-frequency characteristics.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway plan view showing an embodiment of the speaker diaphragm of the present invention, Fig. 2 is a perspective view of a frame member used in the diaphragm, and Fig. 3 is a cross-sectional view of the same diaphragm and a conventional diaphragm. FIG. 3 is a comparison curve diagram of sound pressure frequency characteristics. 1... Skeleton member, 2... Surface material.

Claims (1)

[Claims] A skeleton member made by bending a rectangular plate-shaped body into a zigzag shape is developed into an annular shape with one side serving as an inner circumferential surface and the other side serving as an outer circumferential surface. 1. A diaphragm for a speaker, comprising a sandwich structure formed by adhering materials, and characterized in that the bending pitch of the annular skeleton member is changed to change the skeleton density in the circumferential direction.