JPH0347040B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a diaphragm for a flat speaker.

Conventional Structure and Problems Cone-shaped speaker diaphragms have been commonly used in the past. This is because the cone shape has extremely high structural strength in the vibration direction.
This is because a wide range of reproduction frequency bands can be obtained even when using relatively low elastic materials such as paper and plastics.

However, a speaker having a cone-shaped recess or the like causes a peak dip in the sound pressure frequency characteristic depending on the degree of recess, which impedes flatness. In order to solve these problems, in recent years, planar diaphragms using a honeycomb sandwich structure or the like have been studied and put into practical use. However, flat diaphragms require complex manufacturing processes such as a honeycomb structure in order to secure the necessary reproduction frequency band, and there are many types of component parts and adhesives, which inevitably increases weight and cost. This is the current situation. Therefore, there has been a desire for a diaphragm for flat speakers that is low in cost and has characteristics equivalent to those of conventional flat speakers.

OBJECTS OF THE INVENTION In view of the above drawbacks, the present invention provides a diaphragm for a flat speaker that has a simple structure and flat sound pressure frequency characteristics without using a complex structure such as a Sanderch structure.

Structure of the Invention The present invention is a cone-shaped cone in which V grooves extending from the inner circumferential end to the outer circumference are continuously provided radially in the circumferential direction,
and the outer peripheral end is a flat part perpendicular to the axial direction.
a diaphragm having a flat surface perpendicular to the axial direction on the outer periphery, and in which inverted triangular pyramids are successively arranged radially, and each inverted triangular pyramid is fitted into each V groove of the first diaphragm. a second diaphragm bonded together to form a circumferential reinforcing wall in the middle of the V groove;
The second diaphragm has a flat part and a surface plate bonded to the inverted triangular pyramid of the second diaphragm.
As a result, the acoustic radiation surface is formed into a substantially flat surface, and although the structure is extremely simple, it has the unique effect of obtaining sound pressure frequency characteristics equal to or higher than those of conventional flat speakers.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the shape of a first diaphragm constituting a diaphragm for a flat speaker according to an embodiment of the present invention. FIG. 1a is a perspective view of the first diaphragm, and FIG. FIG. 1 is a sectional view taken along line A-A' in FIG. 1a.

In FIG. 1, reference numeral 1 denotes a first diaphragm, which has a V-groove that extends radially and continuously in the circumferential direction from the inner circumference end to the outer circumference.
That is, 1a, 1b, 1c, 1c',
It has a cone shape with a V-groove 1f formed by 1d and 1d'. Further, the flat portion 1e provided at the outer peripheral end is perpendicular to the vibration direction (axial direction).

Figure 2 shows the second diaphragm in this embodiment, and Figure 2a is a perspective view of the second diaphragm;
Figure b is a sectional view taken along line B-B' in Figure 2a.

In FIG. 2, reference numeral 2 denotes a second diaphragm, which has a flat surface 2f perpendicular to the axial direction on its outer periphery, and has inverted triangular pyramids arranged radially in series. That is, 2
The triangles formed by a, 2a' and 2b are each fitted into the V groove 1f of the first diaphragm 1 shown in FIG. A circumferential reinforcing wall 2c (vertical line portion) is formed in the middle of the groove 1f. In this embodiment, the base of the inverted triangular pyramid is not extended to the center, but the center side is formed into a shallow dome shape that does not affect the sound pressure frequency characteristics, with the inner diameter portion 2d having the same diameter or more as the voice coil bobbin as the border. This is because by configuring the inverted dome portion 2e to be separated and finally glued together, a gauge for setting the voice coil bobbin in the correct position can be inserted and removed from the top surface of the diaphragm, thereby reducing the defective rate in the manufacturing process. belongs to.

Generally, in order to expand the reproduction frequency band of a planar speaker, the bending strength of the diaphragm in the radial direction is required to be large. Therefore, in this embodiment, the first
It has a structure in which ribs are arranged radially so that the bending strength at the junction point between the diaphragm 1 and the second diaphragm 2, that is, the driving point, is maximized. Furthermore, in order to maximize the effect of the radial ribs, it is necessary to reinforce them in the circumferential direction as well to prevent opening and closing between the ribs. Therefore, in this embodiment, 2a in FIG.
The V-groove 1f of the first diaphragm and the radial ribs formed by the inverted triangular pyramids of the second diaphragm are fixed in the circumferential direction by the triangular reinforcing wall 2c formed by 2b and 2a'. It forms a reinforcing structure.

In addition, the flat part 2f provided on the outer periphery of the second diaphragm 2 in FIG. It's summery.

FIG. 3 shows the overall structure of this embodiment. FIG. 3a is a perspective view of a diaphragm for a flat speaker according to this embodiment, and FIG. 3b is a half sectional view of the same.

The first and second diaphragms are bonded to each other as described above, and the annular surface plate 3 shown in FIG. 3 is bonded to the entire surface except for the central inverted dome portion 2e.
The inner peripheral end 1d of the first diaphragm 1 is bonded to the voice coil bobbin 4 and driven by a magnetic circuit (not shown).

By configuring as described above, the sound radiation surface becomes a completely flat surface except for the inverted dome 2e at the center, and a flat sound pressure frequency characteristic can be obtained.

The diaphragm of the present invention can be easily manufactured using lightweight materials such as wood pulp papermaking or plastic film molding, making it possible to obtain a high-performance flat diaphragm at low cost. It is possible.

Effects of the Invention As described above, the present invention obtains a planar acoustic radiation surface by combining a plurality of diaphragms, and also reinforces the joint portion of the first and second diaphragms in the radial direction and the circular wave direction. With this structure, it is possible to provide a diaphragm for realizing a speaker with flat sound pressure frequency characteristics and a wide reproduction band. Furthermore, compared to conventional examples, the manufacturing method is simpler and the weight can be reduced, providing a low-cost and highly efficient flat speaker.

[Brief explanation of drawings]

FIG. 1a is a perspective view showing a first diaphragm of a diaphragm for a flat speaker in an embodiment of the present invention;
Figure b is a sectional view taken along the line A-A' in Figure 1a, Figure 2a is a perspective view showing the second diaphragm, Figure 2b is a sectional view taken along the line B-B' in Figure 2a, FIG. 3a is a perspective view of the flat speaker diaphragm, and FIG. 3b is a half sectional view of the same. 1...First diaphragm, 1e...Flat portion, 1f...
...V groove, 2...second diaphragm, 2a...reinforcement wall,
2f...Plane part, 3...Front plate.

Claims (1)

[Claims] 1. A first diaphragm having a cone shape in which V grooves extending from the inner circumferential end to the outer circumference are continuously provided radially in the circumferential direction, and the outer circumferential end is a flat part perpendicular to the axial direction; The outer periphery has a flat surface perpendicular to the axial direction, and inverted triangular pyramids are arranged radially in succession, each inverted triangular pyramid is fitted and bonded into each V groove of the first diaphragm, and the a second diaphragm forming a reinforcing wall in the circumferential direction in the middle of the V-groove; and a surface plate bonded to a flat surface of the second diaphragm and an inverted triangular pyramid of the second diaphragm. A diaphragm for a flat speaker, characterized by comprising: