JP4085313B2 - Omnidirectional speaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a speaker in which sound waves generated by surface vibration of a diaphragm are non-directional.
[0002]
[Prior art]
As a speaker of an audio device, a vibration in which a permanent magnet plate having strip-shaped N poles and S poles alternately formed on a plate surface and electric wiring extending along the boundary region between the N poles and the S poles is formed on the plate surface A thin flat panel speaker combined with a plate has been proposed. This thin flat speaker can be reduced in weight and space, has a strong directivity of emitted sound waves, and has a characteristic of allowing sound waves to propagate further.
[0003]
[Problems to be solved by the invention]
In general, in a loudspeaker, a radiated sound wave has directivity in a direction parallel to the installation surface, and thus a range in which a good sound can be heard is limited. In view of this, some speaker units are provided on the peripheral side surface of the cylindrical housing to achieve omnidirectionality. However, this is problematic in that it increases in size and becomes a multi-sound source. Therefore, an omnidirectional speaker device using a thin flat panel speaker that is advantageous for weight reduction and space saving is proposed. However, even in this case, it is necessary to combine a plurality of permanent magnet plates and diaphragms so that the directivity directions of the radiated sound waves are different, which complicates the configuration and increases the weight and costs. Also leads to higher problems.
[0004]
OBJECT OF THE INVENTION
In view of the problems inherent in the above-described conventional technology, the present invention has been proposed to suitably solve this problem, and provides an omnidirectional speaker that is simple in structure, lightweight, and low in cost. For the purpose.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems and to achieve the intended purpose suitably, the omnidirectional speaker according to the present invention is a permanent magnet composed of a bonded magnet in which strip-shaped N poles and S poles are alternately formed on a plate surface. A magnet plate and a diaphragm formed on the plate surface with electrical wiring extending along the boundary region between the N pole and the S pole are accommodated in a casing with a cushioning material sandwiched therebetween, and sound waves are generated by the surface vibration of the diaphragm. The resulting speaker,
The casing is formed in a curved shape , and the permanent magnet plate, the diaphragm, and the buffer material accommodated in the casing have a curved shape similar to that of the casing .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Next, the omnidirectional loudspeaker according to the present invention will be described below with reference to the accompanying drawings by way of preferred embodiments.
[0007]
1 and 2 show a speaker according to an embodiment. The speaker 10 includes a permanent magnet plate 12, a diaphragm 14 disposed so as to face the permanent magnet plate 12, and the diaphragm 14. Is basically composed of a pair of shock-absorbing materials 16 interposed on both sides of the front and back, and a casing 18 that accommodates them, and the overall outer shape thereof has a substantially sin curve in a plane (see FIG. 3).
[0008]
The permanent magnet plate 12 is a flexible bonded magnet formed into a sheet having a required thickness (for example, 2 mm) by mixing magnetic powder into a resin material, and substantially the entire plate surface facing the diaphragm 14. In addition, strip-shaped N poles and S poles are alternately formed. A large number of through holes 12a are formed in a predetermined pattern in the boundary region between the N pole and the S pole.
[0009]
The vibration plate 14 is a thin, soft and flexible resin film, and the electric wiring 20 is printed in a meandering manner over both the front and back plate surfaces. It is connected to a power supply terminal portion 22 provided at the center of one side of the diaphragm 14. The diaphragm 14 and the permanent magnet plate 12 are arranged to face each other so that straight portions (portions other than the turn portion) of the electric wiring 20 alternately extend in opposite directions along the boundary region between the N pole and the S pole. The In the embodiment, the front surface of the diaphragm 14 and the back surface of the permanent magnet plate 12 are arranged so as to face each other, and when an AC signal is input to the power supply terminal portion 22, the magnetic flux lines from the N pole to the S pole are crossed. In the electric wiring 20 extending in the opposite direction, a force in the same direction acts on the front side or the back side (thickness direction) according to the polarity of the AC signal according to Fleming's left-hand rule, and the diaphragm 14 vibrates. Is configured to produce
[0010]
The cushioning material 16 interposed between the front and back sides of the diaphragm 14 is soft and has air permeability that allows sound waves to pass therethrough, and is composed of, for example, a non-woven sheet having substantially the same size as the diaphragm 14. It functions to prevent the generation of abnormal noise due to contact with the permanent magnet plate 12 and a base member 26 described later.
[0011]
As shown in FIG. 2, the casing 18 includes a front cover member 24 and a rear base member 26 which are symmetrical before and after exhibiting a substantially sin curve in a plane, and both the members 24 and 26 have a constant outer peripheral width. The inner space excluding the flanges 24a and 26a is formed into a container shape that is shallowly recessed, and the flanges are brought into contact with each other in the front-rear direction and fixed with fixing means such as bolts, thereby forming a required space inside. It has come to be. The permanent magnet plate 12, the buffer member 16, the diaphragm 14, and the buffer member 16 that are stacked in order from the front side have a portion corresponding to the outer peripheral edge of the diaphragm 14 where the electrical wiring 20 is not formed. , 26 a and is accommodated in the space of the casing 18. That is, the permanent magnet plate 12, the diaphragm 14, and the pair of cushioning members 16 are accommodated in the space in a posture that has a substantially sin curve in a plane, following the shape of both the members 24 and 26. In the embodiment, the N pole and S pole of the permanent magnet plate 12 and the straight portion of the electric wiring 20 in the diaphragm 14 are set to extend in the horizontal direction, but may extend in the vertical direction. Good. Further, the cover member 24 and the base member 26 are formed with through holes 24b and 26b that coincide with the through holes 12a formed in the permanent magnet plate 12, and sound waves generated by the diaphragm 14 are transmitted through these through holes. It is configured to be efficiently radiated out of the casing 18 through 12a, 24b, and 26b.
[0012]
As shown in FIG. 1, the speaker 10 having the casing 18 as an outer shell includes a first bending portion 10 a that curves in a semicircular shape that protrudes from one side (left side in the drawing) to the back side (rear side), and the other side. A second curved portion 10b that curves in a semicircular shape convex from the front side (front side) to the front side (front side in the figure) is connected to form a substantially sin curve in a plane. That is, both the front and back surfaces of the first bending portion 10a and the second bending portion 10b, which are the sound wave emission surfaces of the speaker 10, are set to face almost all directions in two dimensions, and the speaker 10 of the embodiment is horizontal. It is configured to have 360 ° omnidirectionality in the direction.
[0013]
Incidentally, as shown in FIG. 3, in the speaker 10 of the embodiment, the central angle of the arc portion in both the curved portions 10a and 10b is set to 135 ° and the radius is set to 40 mm, but the value can be arbitrarily changed. . It is also possible to set the central angle and the radius of the first bending portion 10a and the second bending portion 10b to be different.
[0014]
[Effect of the embodiment]
Next, the operation of the speaker according to the above-described embodiment will be described. In the speaker 10, when an AC signal is input to the power supply terminal portion 22, the diaphragm 14 is moved in the front-rear direction according to Fleming's left-hand rule of the permanent magnet plate 12 and the diaphragm 14 housed in the casing 18. Surface vibrations generate sound waves. In this case, the diaphragm 14 and the casing 18 have a substantially sin curve in the plane, and the sound wave radiation surface is directed in all directions of 360 ° in the horizontal direction. Therefore, as shown in FIG. Sound waves are emitted from all directions in all directions in the horizontal direction. In other words, the speaker 10 of the embodiment is 360 ° omnidirectional in the horizontal direction parallel to the installation surface of the speaker 10, and the range in which a good sound can be heard is not limited. In addition, since the permanent magnet plate 12 and the diaphragm 14 are each composed of a single plate, the sound source is simple and the structure is simple, the weight can be reduced, and the manufacturing cost can be reduced.
[0015]
[Experimental example]
Conventional example using one thin flat speaker, Conventional example 2 in which two thin flat speakers are combined in an L shape, and the invention example which is a speaker according to the above example, each frequency of 1 kHz and 2 kHz FIG. 4A, FIG. 5A, and FIG. 6A show the results of measuring the sound pressure characteristics in all directions in two dimensions when the AC signal is input. As shown in FIG. 4 (b), the front and back surfaces of the speaker in Conventional Example 1 are oriented at 0 ° and 180 °, and the speaker is installed in Conventional Example 2 in FIG. ), The front and back surfaces of one speaker are set to face 0 ° and 180 °, and the front and back surfaces of the other speaker orthogonal to this are set to face 90 ° and 270 °. In addition, as shown in FIG. 6B, the installation posture of the speaker in the invention example is set so that the inner peripheral surface of the first bending portion faces 0 ° and the inner peripheral surface of the second bending portion faces 180 °. Is done.
[0016]
In Conventional Example 1, as shown in FIG. 4A, the sound pressure characteristics at 90 ° and 270 ° at which the left and right ends of the speaker face are particularly low, and the variation in sound pressure characteristics in all directions is large. In Conventional Example 2, as shown in FIG. 5A, high sound pressure characteristics are obtained at 0 °, 90 °, 180 °, and 270 ° where the plate surfaces (front and back surfaces) of the two speakers face each other. Sound pressure characteristics at 45 °, 135 °, 225 °, and 315 ° are different from each other, that is, 45 °, 135 °, 225 °, and 315 °, and the sound pressure characteristics in all directions still vary. On the other hand, in the invention example, as shown in FIG. 6A, it was confirmed that high sound pressure characteristics with little variation (flattened) were obtained in almost all directions.
[0017]
[Another example]
FIG. 7 shows a speaker according to another embodiment, which has the same basic configuration, except that the outer shape is a dome-shaped curved surface. That is, in the speaker 28 of this other embodiment, the cover member 24 and the base member 26 constituting the casing 18 are formed in a dome shape, and the space defined internally by combining both the members 24 and 26 is the same. A dome-shaped permanent magnet plate 12, a diaphragm 14, and a pair of cushioning members 16 are accommodated. Accordingly, when the speaker 28 is placed on the floor surface, the surface emitting the sound wave is directed in all directions above it, and the omnidirectionality in all directions above the floor surface is obtained. If the speaker 28 is installed on the ceiling face downward (in a state of being convex downward), the speaker has omnidirectional speakers in all directions below.
[0018]
[Example of change]
The external shape of the speaker of the present application is not limited to the shapes of the above-described embodiments and other embodiments, and U, J, C-shapes and other free curved surfaces can be adopted. In the embodiment, the permanent magnet plate is disposed only on one plate surface side (surface side) of the diaphragm, but a configuration in which the permanent magnet plates are disposed on both plate surface sides sandwiching the diaphragm may be employed. Further, the cushioning material may be a frame-like material that comes into contact only with the outer peripheral edge portion outside the electric wiring formation region on the diaphragm.
[0019]
【The invention's effect】
As described above, according to the omnidirectional speaker according to the present invention, by making the permanent magnet plate and the diaphragm have curved surfaces, the sound wave generated by the surface vibration of the diaphragm becomes omnidirectional and is not directed to the speaker. The range in which a good sound can be heard is expanded. Moreover, since it can be composed of one permanent magnet plate and diaphragm, the structure is simple, light weight and low cost can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a speaker according to a preferred embodiment of the present invention.
FIG. 2 is a schematic perspective view showing the speaker according to the embodiment in an exploded state.
FIG. 3 is an explanatory diagram illustrating a shape of a speaker according to an example.
4 is a graph of an experimental example according to Conventional Example 1 and an explanatory diagram of an installation posture. FIG.
5 is a graph of an experimental example according to Conventional Example 2 and an explanatory diagram of an installation posture. FIG.
FIG. 6 is a graph of an experimental example according to an example of the invention and an explanatory diagram of an installation posture.
FIG. 7 is a schematic perspective view of a speaker according to another embodiment.
[Explanation of symbols]
12 Permanent magnet plate 14 Diaphragm 16 Buffer material 18 Casing 20 Electric wiring

Claims (3)

A permanent magnet plate (12) made of a bond magnet in which strip-shaped N poles and S poles are alternately formed on the plate surface, and electric wiring (20) extending along the boundary region between the N pole and the S pole. formed vibration plate (14) housed in the casing (18) in a state sandwiching the cushioning material (16), wherein a loudspeaker produces a sound wave by the surface vibration of the diaphragm (14) to,
The casing (18) is formed in a curved shape, and the permanent magnet plate housed in said casing (18) (12), the diaphragm (14) and cushioning material (16) is similar to the casing (18) An omnidirectional speaker characterized by a curved shape . The omnidirectional speaker according to claim 1 , wherein the casing (18) has a substantially sin curve in a plane. The casing (18) The omnidirectional speaker according to claim 1, which has a dome-shaped curved surface shape.

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