JP2510607B2 - Flat speaker - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a speaker that is made thinner by reducing the depth dimension.

“Conventional Technology and Problems” Conventionally, a horn type and a cone type are known as speaker systems.

Among these, the horn type speaker has a structure in which a voice coil (driving means) for converting electric energy of an input signal into mechanical motion and a diaphragm are provided at the base end of a horn whose tip is open like a tail. Therefore, there is a problem that a depth dimension (a dimension from the opening of the horn toward the rear) corresponding to the length of the horn is required.

On the other hand, the cone type speaker is one in which a voice coil is provided at the base end of a cone-shaped diaphragm, and the depth dimension can be made smaller than that of the horn type speaker. In order to eliminate the influence of the reverse-phase component that occurs, an enclosure with a certain area or volume such as a flat type, a closed type, or a bass reflex type is required, and it is possible to avoid making it large as a whole. Absent.

In addition, since the speaker frame supporting the diaphragm is attached to the baffle plate on the front surface of the enclosure, a signal of the speaker driving means is transmitted to the enclosure via the frame or the like and resonates. Or, the phenomenon that the enclosure vibrates due to the increase in air pressure caused in the enclosure by the movement of the cone, and the vibration caused by these phenomena interferes with the vibration of the cone, that is,
It is unavoidable that the vibration characteristics of the enclosure adversely affect the vibration characteristics of the cone and interfere with hi-fi reproduction.

In addition, a flat speaker in which the edge of the speaker diaphragm is separated from the baffle plate has also been announced.
In this flat speaker, due to the fact that the diaphragm is flat and has a large front surface area, the sound waves generated from the diaphragm are easily dissipated in the directions other than the listening point, and the sound waves are generated near the outer peripheral edge of the diaphragm. May wrap around to the side or the back of the diaphragm, which may cause deterioration of reproduced sound quality.

In view of the above circumstances, the present applicant proposed a "flat speaker" in Japanese Patent Application No. 62-89071 and regulated sound wave diffusion around the flat speaker to prevent sound quality deterioration. The present invention further improves the flat speaker according to the above-mentioned prior application to make it thinner, and in particular, as an acoustic system attached to a thin image monitor (for example, one that uses liquid crystal) that is becoming popular in the AV era. An object of the present invention is to provide a speaker that is optimal for use in a wall-mounted state.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention has a section parallel to the axis near the periphery of a curved plate having a cross section orthogonal to the axis curved to the back side. A flat plate is provided so as to form a part of a flat plate, and a driving means for converting electric energy into kinetic energy of the flat plate is connected to one surface of the flat plate.

[Operation] With the above configuration, the air held inside the curved plate can be sent forward while vibrating. Therefore, without using an enclosure with a certain area or volume, the surroundings of sound waves Of course, it is possible to prevent the release to the
Since the drive means is provided on the rear side of the flat plate located on the front side of the bending direction of the bending plate, the amount of protrusion of the diaphragm toward the rear side is small.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

A reference numeral 1 in the drawing is a diaphragm, and the diaphragm 1 is composed of a curved plate 2 and flat plates 3 provided on both sides of the curved plate 2, as shown in FIG. .

Both sides of the curved plate 2 are curved so as to form a part of a substantially cylindrical (elliptical cylinder) surface, and a central portion is substantially flat and is curved in one direction as a whole.
The plane plate 3 forms a part of a plane substantially parallel to the axis of the bending plate 2, and is fixed to both side edges of the bending plate 2.

Further, lateral ribs 4A to 4D having a planar shape substantially equal to the shape of the cross section of the bending plate 2 orthogonal to the axis are fixed to both ends and the intermediate portion of the bending plate 2. Vertical ribs 5A to 5F directed in a direction orthogonal to the horizontal ribs 4A to 4D are provided between the horizontal ribs 4A to 4D, and the horizontal ribs 4A to 4F are provided at respective portions.
4D are connected to each other, and the vertical ribs 5A to 5F are also fixed to the surface of the curved plate 2. Furthermore, between the vertical ribs 5A and 5B and the curved plate 2, between the vertical ribs 5C and 5D and the curved plate 2, and between the vertical ribs 5E and 5F and the curved plate 2, the corresponding portions are curved. Lateral ribs 6A, 6B, 6C, 6D, and 6E, 5F each having a planar shape corresponding to the cross-sectional shape of the plate 2 are fixed to each other to form a lattice shape as a whole.

The curved plate, the flat plate, and the vertical and horizontal ribs are preferably lightweight and highly rigid, and in this embodiment, a balsa material is used. In addition, all of these members are combined by plate cutting so that the direction of the fibers is in the longitudinal direction of the member. Further, in this embodiment, the curved plate 2 is formed into the shape shown by elastically deforming a flat plate, and each rib is formed so as to maintain this elastically deformed state (state in which internal stress is generated). A structure fixed to the curved plate 2 is adopted, and the vibration propagation speed can be increased by causing the internal stress in this manner.

As shown in FIGS. 1 to 3, the diaphragm 1 having the above-described configuration is arranged inside a frame-shaped frame member 7, and the outer periphery of the diaphragm 1, that is, the flat plates 3 and 3 on both sides. And between the upper and lower horizontal ribs 4A and 4D and the inner circumference of the frame member 7,
Edge materials 8 are provided to prevent the flow of air between them. The edge material 8 is the second
It has a cross-sectional shape as shown in Fig. 3 or Fig. 3,
For example, a material having a high elasticity and a good vibration damping property such as urethane foam resin is applied.

Further, the vibration plate 1 includes six drive units 9
Is connected. These drive units 9 are arranged on the back surfaces of the two flat plates 3 by three, respectively, and actuate between the voice coil 10 and the magnet 11 by supplying an electric signal of the voice coil (moving coil) 10. It functions as a driving unit that drives the diaphragm 1 by the electromagnetic force. The magnet 11 is fixed to the inner surface of the back plate 12 provided on the back surface of the frame member 7. Further, the voice coil 10 is
It is connected to the frame 13 integrated with the magnet 11 via a damper 14 which is elastically deformable.

Further, by providing the opening 12a in the back plate 12,
A structure in which a closed chamber (a space in which air is compressed and a back pressure is generated) is not formed on the back side of the diaphragm 1.

Further, a high frequency speaker 16 is supported by a support member 15 attached to the back plate 12 so as to straddle the opening 12a. The high frequency speaker 16 is a speaker having a dome-shaped diaphragm generally used for high frequencies, and has a hole 17 formed so as to penetrate substantially the center of the diaphragm 1.
It is exposed to the front side of the diaphragm 1 through the and is adapted to directly radiate a sound wave. Further, the hole 17 has an inner diameter that causes a space in the radial direction with respect to the high frequency speaker 16 so as not to interfere with the movement of the bending plate 2.

The treble speaker 16 is connected to a drive circuit (not shown) such as a power amplifier together with the drive unit 9, and the treble tone of the musical sound reproduced from the diaphragm 1 (for example, a region of several thousands Hz or more). ) Plays a complementary role. In the embodiment, the high frequency speaker 16
By providing a so-called high-pass filter (not shown) between the drive circuit and the drive circuit, only a signal of several thousand Hz or higher is input to the high-frequency speaker 16.

Further, by setting the mounting position of the treble speaker 16 so that the drive unit of the treble speaker 16 and the drive unit 9 of the diaphragm 1 coincide with each other in the depth direction, the musical sound and the treble sound generated from the diaphragm 1 are set. The phase is matched with the tone generated by the speaker 16 for use.

The reference numeral 18 in the figure indicates each drive unit 9
The reinforcing material for reinforcing the connection portion between the curved plate 2 and the flat plate 3 from the front side in the vicinity of the connection portion, and the reference numeral 19 is a reinforcing material for reinforcing the same from the back side.

In the flat speaker configured as described above, the drive unit 9 converts the energy of the electric signal into mechanical energy as reciprocating movement of the voice coil 10 (reciprocating movement in the direction orthogonal to the plane plate 3) and vibrates. Board 1
The curved plate 2 can be vibrated to generate a musical sound. Inside the curved plate 2, as shown in the drawing, the curved plate 2
Front side of the, horizontal ribs 4A-4D, 6A-6F, and vertical rib 5A
Since a space surrounded by ~ 5F is formed, the air held in this space is pushed out in front of the diaphragm 1. Further, since the diaphragm 1 functions as a flat baffle that prevents the sound waves from wrapping around the high frequency speaker 16 from the front side, the acoustic characteristics of the high frequency speaker 16 are improved without providing a special baffle plate. You can

Further, since the diaphragm 1 has a curved shape as shown in the drawing, it is similar to a so-called tone distortion (also called a line speaker) in which a plurality of speakers are arranged in a straight line in the vertical direction, as shown in FIG. 1 or FIG. It is possible to obtain a good directional characteristic in the left and right direction. Therefore, when two-channel stereo reproduction is to be performed, a flat speaker oriented in the direction as shown in FIG.
By arranging them side by side in the left-right direction of the figure, good stereo reproduction performance can be exhibited.

"Modified Embodiment" (a) The mounting position of the flat plate is not limited to the side edge portions of the curved plate as in the embodiment, and the flat plates are attached to the upper and lower ends to connect the flat plate to the drive unit. You may do it.

(B) The number of drive units to be mounted is not limited to that in the above-described embodiment, and more or fewer drive units may be provided at positions symmetrical about the curved plate.

(C) In the above-described embodiment, the high-frequency speaker is also used, but depending on the frequency band to be reproduced, this may be omitted and the diaphragm may function as a so-called full-range speaker. Further, if necessary, a flat speaker and a low-pitched speaker may be used together.

(D) The shape of the curved plate is not limited to the above-described embodiment, and the shape of the cross section (cross section orthogonal to the axis) forms a part of an arc of a perfect circle or an ellipse, or a curvature. Needless to say, various shapes such as a shape in which a plurality of different arcs are combined or a polygonal shape can be adopted.

(E) The plurality of drive units for driving the planar diaphragm may be electrically connected in any combination of series, parallel, and serial / parallel, and may be appropriately selected according to the output characteristics of the drive circuit.

(F) The material of the diaphragm is not limited to the wood as in the above-described embodiment, and new materials such as plastics such as polycarbonate as well as materials such as pulp applied to the conventional speaker are applied. Of course it is good.
The curved plate is not necessarily in an elastically deformed state (in which internal stress is generated), and may be in a curved state as shown by being plastically deformed by heat treatment or the like.

[Advantages of the Invention] As is apparent from the above description, according to the present invention, the flat plate is provided on the peripheral portion of the curved plate, and the driving means is connected to the flat plate. Not only can the sound pressure be ensured by reliably pushing out the air held in the space toward the front listening point, but also by using the space that naturally occurs on both sides of the bending part on the back side of the bending plate. The drive means can be housed in the lever space,
Therefore, make the depth (thickness) smaller than the horn type and cone type speakers that have a drive unit at the base end part of the horn and the base end part of the cone located deepest from the front of the speaker. You can
Further, in combination with the fact that no special enclosure is required, it is possible to realize a thin speaker suitable as a speaker used together with an image monitor or as a speaker incorporated in an AV device.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show one embodiment of the present invention. FIG. 1 is a front view, FIG. 2 is a view taken along the line II-II of FIG. 1, and FIG. 1 is a view taken along the line III-III in FIG. 1, and FIG. 4 is a perspective view showing the appearance of the diaphragm. 1 ... Vibration plate, 2 ... Curved plate, 3 ... Flat plate, 4A-4D,
6A to 6F ... horizontal ribs, 5A to 5F ... vertical ribs, 7 ... frame member, 9 ... drive unit (driving means).

Claims (1)

(57) [Claims] 1. A curved plate having a shape in which a cross section orthogonal to the axis is curved to the back side, and a flat plate mounted in the vicinity of the periphery of the curved plate so as to form part of a plane parallel to the axis. A flat speaker comprising: a face plate; and a driving unit attached to the back side of the plane plate and converting electric energy into kinetic energy of the plane plate.