JPH028320Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acoustic lens that is simple in structure and easy to assemble.

Conventionally, acoustic lenses have been used to improve the directivity of a speaker or to lengthen the sound path path of a specific sound range to delay the phase. FIG. 1 is a perspective view showing an example of such an acoustic lens, which is a swash plate made of a plurality of plates stacked in parallel with a notch 1a formed in the center of one side of a plate material 1 such as a plate-shaped synthetic resin or light metal plate. It is a type acoustic lens. This swash plate type acoustic lens is used by arranging the plate surface at an angle with respect to the sound path indicated by the broken line as shown in the side view of FIG.

FIG. 3 is an assembled perspective view showing an example of an obstacle type acoustic lens, in which ring-shaped spacers 2 and toric bodies 3 having an opening of a predetermined diameter in the center of a circular perforated plate are stacked alternately. It is housed in the hollow part of the cylindrical body 4 as shown in the cross-sectional view. in this case,
Sound waves that enter through the opening on one side of the cylindrical body 4 are emitted from the opening on the other side so as to be diffused.

However, all of these conventional configurations have the problem of having a large number of parts, making assembly difficult, and resulting in high costs.

The present invention was devised to solve these problems, and aims to provide an acoustic lens that has a small number of parts, is easy to assemble, and is therefore inexpensive.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 5 to 7.

In the figure, 11 is a nearly rectangular band-shaped perforated plate made of, for example, thermoplastic synthetic resin, and has a large number of through holes 11 on the plate surface.
It forms a. Then, this perforated plate 11 is rolled up from one end in the longitudinal direction, and as shown in FIG. 6 or 7.
As shown in the figure, the acoustic lens has a spiral cross section perpendicular to the axial direction. At this time, the pitch of each winding layer in the spiral winding of the perforated plate 11, that is, the gap size between the layers, is gradually varied in the radial direction.

Therefore, as shown in the cross-sectional view in Figure 6,
If the spiral pitch P is made larger toward the outer periphery (smaller toward the inner periphery) and rolled and molded, a sound collecting lens with a narrower sound path closer to the center will be obtained. On the other hand, the seventh
As shown in the cross-sectional view in the figure, if the pitch P is made smaller toward the outer periphery (larger toward the inner periphery), the farther from the center the lens is, the narrower the sound path becomes.

With such a configuration, a sound path can be formed between the surfaces of the perforated plate having a spiral cross section, and an acoustic lens that slows down the sound speed of sound waves and bends the path according to the width of the sound path can be obtained. Therefore, the component is only the band-shaped perforated plate 11 of a predetermined shape, and the simple process of winding it from the end is performed, so that the productivity is extremely high. Further, the characteristics as an acoustic lens can be appropriately adjusted by adjusting the spiral pitch of the cross section, the size of the holes in the perforated plate, the interval between the holes, the overall size, etc.

Note that the present invention is not limited to the above-mentioned embodiments; for example, although thermoplastic synthetic resin was used in the above-mentioned embodiments, molding may be performed using a molded resin, or a metal plate may be formed by press working. Alternatively, the material may be molded into a predetermined shape and then rolled up.

As described in detail above, the present invention uses a band-shaped perforated plate that is wound in an almost spiral shape by changing the pitch along its length, so the structure is simple and the number of parts is small, making it easy to process and assemble. It is possible to provide an acoustic lens that is easy and inexpensive.

[Brief explanation of drawings]

Figures 1 and 2 are a perspective view of an example of a conventional swash plate type acoustic lens and a diagram showing a sound path, and Figures 3 and 4 are an assembled perspective view and a cross section of an example of a conventional obstacle type acoustic lens. Figures 5 to 7 show an embodiment of the present invention. Figure 5 is a developed view of a perforated plate, Figure 6 is a sectional view of a converging lens, and Figure 7 is a sectional view of a diffusing lens. be. 11... Perforated plate, 11a... Hole.

Claims (1)

[Scope of utility model registration request] An acoustic lens characterized in that a substantially band-shaped perforated plate is wound in a substantially spiral shape in the length direction, with the gap size between each wound layer gradually varying in the radial direction.