JPS62236300A - Flat type speaker - Google Patents

Abstract

PURPOSE:To drive and damp the entire body of an oscillation source by using two sheets of amgnetic sheets that are disposed parallel with each other keeping a clearance and held so that they relatively shift in the direction of plane. CONSTITUTION:The first magnetic sheet 1 is, at its own peripheral part, connected to a stationary part 4 via, for instance, an edge 3 that is corgated. The second magnetic sheet 2 is mechanically coupled with a driving mense 7 provided on a stationary part 6. In the magnetic sheets 1 and 2, magnetic signals whose magnetic potntial varies respectively along the directions of bidirectional arrow 8 with constant periods equal to each other. The means 7 gives the magnetic sheet 2 an action in the direction of arrow 8 corresponding to a voice signal. Associatively with the said shifting of the sheet 2, the two sheets 1 and 2 repel and attract each other. Hence the magnetic sheet 1 itself oscillates and generates an acoustic energy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a flat speaker, and particularly to a flat speaker with a novel vibration source driving method.

[Prior Art] For example, a piezoelectric speaker is a type that can advantageously realize a planar speaker. In piezoelectric speakers, as a means of converting electrical energy into mechanical energy,
A piezoelectric element is used and a suitable diaphragm is used to convert the mechanical vibrations of the piezoelectric element into acoustic energy. That is, in a piezoelectric speaker, the piezoelectric element and the diaphragm are mechanically coupled.

[Problems to be Solved by the Invention] The piezoelectric speaker described above uses a flat diaphragm, and by using a thin piezoelectric element, an extremely thin planar speaker can be obtained. .

However, in general, piezoelectric speakers use a piezoelectric element that is smaller than the area of the diaphragm, and are either brought into close contact with the diaphragm or mechanically coupled to the diaphragm using an appropriate connection means. ing. Therefore, in a piezoelectric speaker, the piezoelectric element applies driving and braking to the diaphragm not entirely but partially. Therefore 9. There is a limit to how high the efficiency can be, and the damping factor cannot be expected to be that high.

Therefore, this invention adopts a new drive method to enable full-scale driving and full-braking of the vibration source, and
The aim is to provide a flat speaker that is suitable for thinning.

[Means and effects for solving the problems] The present invention provides first and second magnetic sheets, which are arranged in parallel with a distance from each other and held so as to be relatively displaced in the plane direction; a driving means for driving the first or second magnetic sheet to be displaced in the planar direction in response to an audio signal; and a driving device orthogonal to the planar direction so as to use the first magnetic sheet as a vibration source. and supporting means for supporting the first magnetic sheet so as to be able to vibrate in the direction of the magnetic sheet. A magnetic signal whose magnetic potential changes along the direction of the displacement is recorded on each of the first and second magnetic sheets.

According to such a configuration, when the first and second magnetic sheets are relatively displaced in the planar direction by the driving means, the force acting between the first and second magnetic sheets in accordance with this displacement is changes. This change in force causes the first magnetic sheet to vibrate in a direction perpendicular to its surface direction. Since the change in the force acting between the first and second magnetic sheets is correlated to the audio signal input to the driving means, vibrations correlated to this audio signal are applied to the first magnetic sheet, and the first Acoustic energy is generated from the magnetic sheet.

[Effects of the Invention] According to the present invention, magnetic signals can be recorded over the entire surface of each of the first and second magnetic sheets.
and the force acting between the first and second magnetic sheets that changes depending on the relative displacement of the second magnetic sheet in the planar direction,
It can be applied evenly over the entire surface or almost the entire surface of the first and second magnetic sheets. Therefore, the first magnetic sheet, which serves as a vibration source, is driven entirely, increasing the efficiency of the speaker. Furthermore, for the same purpose, the first magnetic sheet is fully damped, resulting in an excellent damping factor. Furthermore, since the first magnetic sheet as a vibration source moves as a whole, it is possible to obtain a speaker with fewer divided vibrations and a low distortion rate.

Furthermore, most notably, the thickness direction dimension of the speaker is substantially determined by the distance between the respective outer surfaces of the first magnetic sheet and the second magnetic sheet that are arranged in parallel. Therefore, it is possible to obtain an extremely thin planar speaker, and for example, it can be advantageously used as a wall-mounted speaker. Also, the first and second
The area of the magnetic sheet can be arbitrarily set according to the use of the flat speaker. Therefore, it is possible to freely design speakers ranging from relatively small area speakers to large area speakers.

[Embodiment] FIG. 1 is a front view showing the principle of an embodiment of the present invention.

First and second magnetic sheets 1 and 2 are arranged parallel to each other with a distance maintained between them. In FIG. 1, the thickness directions of these magnetic sheets 1 and 2 appear in the front.

The first magnetic sheet 1 is connected to a fixed portion 4 at its outer peripheral portion via, for example, a corrugated edge 3. Thereby, the first magnetic sheet 1 is supported so as to be able to vibrate in a direction perpendicular to its surface direction, that is, in a direction indicated by a double-headed arrow 5. Moreover, by such a support mode, the first magnetic sheet 1 is maintained at an appropriate distance from the second magnetic sheet 2.

The second magnetic sheet 2 is mechanically coupled to a driving means 7 provided on the fixed part 6. The driving means 7 is composed of, for example, a piezoelectric element or an electromagnetic driving means, and thereby drives the second magnetic sheet 2 so as to be displaced in its surface direction, that is, in the direction indicated by the double-headed arrow 8.

On the first and second magnetic sheets 1.2, magnetic signals whose magnetic potentials change at a constant period equal to each other are recorded along the direction of the double-headed arrow 8, respectively. In the illustrated embodiment, these magnetic sheets 1 and 2 have N poles, S poles, N poles, .
In this way, mutually opposite magnetic poles are arranged alternately. Furthermore, when each of the magnetic sheets 1 and 2 is viewed in plan, the N and S poles extend in the width direction (direction perpendicular to the paper surface of FIG. Pole and S pole are distributed. Note that instead of this distribution of magnetic poles, for example, the magnetic poles may be arranged in a checkered pattern.

In order to record the magnetic signals as described above, the first and second magnetic sheets 2 may be made of, for example, a sheet of plastic coated with ferrite, or a sheet of plastic kneaded with ferrite.

In the configuration shown in FIG. 1, an audio signal is given to the driving means 7, and the driving means 7 moves the arrow 8 according to the audio signal.
directional motion is given to the second magnetic sheet 2. The second magnetic sheet 2 is thereby displaced in the plane direction relative to the first magnetic sheet 1, specifically in the direction of the arrow 8. In response to such displacement, the first and second magnetic sheets 1 and 2
The forces acting between them change. That is, the second magnetic sheet 2
As the first magnetic sheet 1 and the second magnetic sheet 2 are displaced in the direction of arrow 8, the first magnetic sheet 1 and the second magnetic sheet 2 exert a force that repels each other or a force that attracts each other, and the magnitude of these forces increases. It also changes. In this way, Edge 3
The first magnetic sheet 1 supported by vibrates itself and generates acoustic energy.

FIG. 2 shows another embodiment of the invention, drawn in a similar manner to FIG.

The first magnetic sheet 11 and the second magnetic sheet 12 shown in FIG. 2 have the same structure as the magnetic sheet 1.2 described above. In this example, the first magnetic sheet 1
1 is connected to a fixing portion 14 near the edge of its outer peripheral portion via an edge 13 extending perpendicularly to the surface direction of the magnetic sheet 11 . Edge 13 is corrugated. Further, the second magnetic sheet 12 is fixed to the fixed part 15. Furthermore, there is an edge 1 between the first magnetic sheet 1 and the second magnetic sheet 2.
3, corrugated edges 16 are connected. These edges 13 and 16 allow the first magnetic sheet 11 to move in a direction perpendicular to its surface direction;
That is, it is supported so as to be able to vibrate in the direction indicated by the double-headed arrow 17. Moreover, the first magnetic sheet 11 is maintained at an appropriate distance from the second magnetic sheet 12 by these edges 13 and 16.

Note that the edge 16 is not the second magnetic sheet 12, but
It may be connected to a suitable fixing part. Furthermore, either the edge 13 or the edge 16 may be omitted.

A driving means 18 operating in response to an audio signal is connected to the fixed part 1
9 , this driving means 18 is connected to the first magnetic sheet 11 . Therefore, the first magnetic sheet 11 is displaced not only in the direction indicated by the double-headed arrow 17 but also in the direction of its surface, that is, in the direction shown by the double-headed arrow 20.

In the embodiment of FIG. 2, the first magnetic sheet 11 is displaced by the driving means 18 in the direction indicated by the double-headed arrow 20. In the embodiment shown in FIG. According to this displacement, the first and second magnetic sheets 11
．． The force that acts during the 12-hour period changes.

This change in force causes the first magnetic sheet 11 to vibrate in the direction indicated by the double-headed arrow 17, generating acoustic energy.

FIG. 3 shows a partially enlarged first magnetic sheet 21 and a second magnetic sheet 22 constituting yet another embodiment of the invention. This example shows another aspect of magnetization, in which each magnetic sheet 21, 22 is magnetized in its thickness direction.

However, as a result, each magnetic seam 1-21°2
On each mutually opposing surface of 2, north and south poles appear alternately. Therefore, these magnetic sheets 21 and 22 are
It can be used as is in place of the magnetic sheets 1 and 2 or the magnetic sheets 11 and 12 in each of the embodiments shown in FIGS. 1 and 2 described above.

Furthermore, although not shown in the drawings, the following example is also possible as a mode of magnetization. That is, as shown in FIG. 3, while magnetizing in the thickness direction of the magnetic sheet, magnetized regions and non-magnetized gap regions are arranged alternately, and on one side of the magnetic sheet, for example, an N-pole region is formed. , non-magnetized region, N
Magnetized regions and non-magnetized regions may appear alternately, such as a polar region. In short, the magnetic sheet used in the present invention only needs to record a magnetic signal whose magnetic potential changes along the direction of displacement by the driving means.

Note that in each of the embodiments shown in FIGS. 1 and 2, the first
Although the first magnetic sheet 1 or 11 itself also served as a diaphragm, another diaphragm may be added using these first magnetic sheets as a vibration source.

[Brief explanation of drawings]

FIG. 1 is a front view showing the principle of an embodiment of the present invention. FIG. 2 is a front view showing the principle of another embodiment of the invention. FIG. 3 is an enlarged view showing a portion of the first and second magnetic sheets 21, 22 used in yet another embodiment of the invention. In the figure, 1, 11.21 are the first magnetic sheets, 2.
12.22 is a second magnetic sheet, 3.13.16 is an edge, 4 and 14 are fixed parts, and 7 and 18 are driving means.

Claims (1)

[Scope of Claims] First and second magnetic sheets arranged parallel to each other with a distance therebetween and held so as to be relatively displaced in the plane direction; a driving means for driving a second magnetic sheet to displace it in the planar direction; a support means for supporting the sheet, wherein a magnetic signal whose magnetic potential changes along the direction of the displacement is recorded on each of the first and second magnetic sheets, and a magnetic signal whose magnetic potential changes along the direction of the displacement is recorded on each of the first and second magnetic sheets; A planar speaker, characterized in that a force acting between the first and second magnetic sheets changes, thereby causing the first magnetic sheet to vibrate.