JPH04165795A - Planar speaker - Google Patents

Abstract

PURPOSE:To dispense with a lead wire and to improve productivity by arranging metal foil on each opposing surface of two foamed resin boards in a manner that the metal foil passes through a projecting part and electrically connecting a piezoelectric sounding body to the metal foil with the help of a conducting adhesive material. CONSTITUTION:Metal foil 5a and 5b are made to adhere to specified positions on the opposing surfaces of foamed resin bodies 3 and 4. These two foamed resin boards 3 and 4 are placed face to face and joined together. The opposing surfaces of the metal foil 5a on a positive side and the metal foil 5b on a negative side atop a projecting part are electrically connected to a piezoelectric sounding body 1 through an electrically conductive adhesive agent 6. At the same time, the piezoelectric sounding body 1 is fixed between projecting parts 3a and 4a, namely, the metal foil 5a on the positive side is electrically connected to the center of a piezoelectric plate 1b atop the projecting part 3a, while the metal foil 5b on the negative side is electrically connected to the center of a metal plate 1a atop the projecting part 4a. Thus, a lead wire is dispensed with and productivity is improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a planar speaker using a piezoelectric sounding body.

(Prior art) The general structure of a flat speaker using a piezoelectric sounding body is as follows.
Two foamed resin plates 3, 4 each having a plurality of recesses 3b, 4b formed on their main surfaces are pasted together such that each recess 3b, 4b faces each other, and within the plurality of recesses 3b, 4b, By each protrusion 3a, 4a in each recess 3b, 4b,
The center portion of the piezoelectric sounding body 1 is held.

As shown in FIG. 5, each piezoelectric sounding body 1 is made up of a circular metal plate 1a and a circular piezoelectric plate 1b (for example, made of PZT) having a smaller diameter than the circular metal plate 1a, which is coaxially attached to the metal plate 1a. Lead wires 9 are soldered to the outer periphery of the metal plate 1a and the electrodes on the surface side of the piezoelectric plate 1b, and an elastic adhesive 1o such as silicone is applied to prevent these lead wires 9 from coming into contact with each other. ing.

As shown in FIG.
, 4, and soldered to a relay board 11 for relaying with an external cable.

(Problems to be Solved by the Invention) In the conventional flat speaker described above, the lead wire is drawn out toward the outer peripheral side of the piezoelectric sounding body. By the way, this outer circumference 1
Since the part 2 is located at the part with the largest amplitude, the two lead wires soldered to the piezoelectric sounding body vibrate and come into contact with each other, producing a chattering sound and deteriorating the sound quality. Therefore, it is necessary to apply an elastic adhesive such as silicone to this part to prevent the lead wires from coming into contact with each other, and this work reduces productivity. This tendency becomes even more pronounced as the number of piezoelectric sounding bodies increases. In addition, it is difficult to make the applied amount and condition of the elastic adhesive uniform.
There is a problem with inconsistent sound quality.

Furthermore, the lead wire soldered to the outer periphery of the piezoelectric sounding body is wired between the opposing surfaces of two foamed resin plates, and is directly soldered to a relay board for relaying with an external cable.
The wiring process and soldering work for the lead wires also causes a decrease in productivity.

(Means for Solving the Problems) A planar speaker according to the present invention includes two foamed resin plates each having a concave portion formed on its main surface, which are pasted together such that the concave portions face each other, and within the concave portion. In the planar speaker in which the center portion of the piezoelectric sounding body is held between the protrusions in the recess, metal foil is wired on each opposing surface of the two foamed resin plates so as to pass through at least the protrusions, and the piezoelectric It is characterized in that a conductive adhesive is interposed between the sounding body and the metal foil, and the piezoelectric sounding body and the metal foil are electrically connected.

(Function) In the flat speaker according to the present invention, since the metal foil is wired on the opposing surface of the foamed resin plate, the lead wire itself becomes unnecessary. Therefore, there is no need to solder the lead wires to the piezoelectric sounding body, solder the lead wires to the relay board, or apply elastic adhesive to the lead wires near the outer periphery of the piezoelectric sounding body.

(Example) An example of the present invention will be specifically described with reference to the drawings. FIG. 1 is a sectional view of a flat speaker according to the present invention.

The diaphragm 2 emits sound from the front side when vibration is applied.
It is formed by pasting two foamed resin plates 3.4 made of foamed polystyrene, foamed polyethylene, etc. in the front-back direction. Both foam resin plates 3.4 have a rectangular shape, but the front foam resin plate 3 is slightly larger than the rear foam resin plate 4, and a stepped portion is formed on the bonding surface of both. Ru. Foamed resin board 3
, 4 are formed with a plurality of recesses 3b and 4b, respectively, and within these recesses 3b and 4b, each recess 3b
, 4b, the plurality of piezoelectric sounding bodies 1 are
The central portions of the two are held together.

2 and 3 are plan views showing the opposing surfaces of the foamed resin board 3.4 used in the present invention, FIG. 2 shows the front foamed resin board 3, and FIG. 3 shows the rear foamed resin board 3. A resin plate 4 is shown.

The plurality of recesses 3b,
4b and protrusions 3a, 4a are respectively formed. In this embodiment, for example, a total of nine four parts 3b, 4b, three vertical rows and three horizontal rows, are formed, and these nine recessed parts 3b,
Projections 3a and 4a are formed within 4b, respectively.

On the front foamed resin board 3, a metal foil 5a such as a tape-shaped copper foil with an adhesive applied to one side is placed in the horizontal direction so as to pass through the apexes of the three protrusions 3a in each of the three horizontal rows. One metal foil 5a is wired in the vertical direction so as to intersect with the left end of the three metal foils 5a wired in the horizontal direction, and these intersections are soldered. The lower end of the vertical metal foil is tangent to the external cable at the outer periphery of the foamed resin plate 3.

The rear foamed resin board 4 is arranged in three vertical directions so that a metal foil 5b such as a tape-shaped copper foil coated with an adhesive on one side passes through the vertices of three protrusions 4a in each of three vertical rows. One metal foil 5b is wired vertically so as to intersect with the lower ends of the three vertically wired metal foils 5b, and these intersections are soldered. Among the three metal foils 5b wired in the vertical direction, the lower end of the rightmost metal foil 5b is
The foamed resin board 4 is connected to an external cable at its outer periphery.

The metal foils 5a and 5b are in the form of tapes with an adhesive applied to one side, and the sides applied with the adhesive are pasted at predetermined positions on the opposing surfaces of the foamed resin plates 3 and 4, respectively. It can be installed by

The metal foils 5a and 5b are made of plastic tape with an adhesive applied to one side and a metal foil such as copper foil individually adhered to the other side, which makes handling easier and improves workability. Improve more.

The metal foil wired to the foam resin board 3 on the front side is the + side metal foil 5
a, The metal foil wired to the foamed resin plate 4 on the rear side becomes the metal foil 5b on one side. The two front and rear foam resin plates 3.4 are pasted together so as to face each other, and the + side metal foil 5a on the apex of the protrusion
A conductive adhesive 6 is applied to the facing side of the metal foil 5b, and the piezoelectric sounding body 1 is electrically connected to the piezoelectric sounding body 1 via the conductive adhesive 6. It is fixed between the protrusions 3a and 4b.

The piezoelectric sounding body 1 is formed by concentrically adhering a piezoelectric plate 1b (for example, made of PZT or the like) having a smaller diameter to one side of a circular metal plate 1a. The + side metal foil 5a is connected to the center of the piezoelectric plate 1b and the conductive adhesive 6 on the apex of the projection 3b.
The - side metal foil 5b is electrically connected to the center of the metal plate 1a via the conductive adhesive 6 on the apex of the projection 4b.

A frame 7 is provided on the peripheral edge of the diaphragm 2 to cover it. The frame 7 has a picture frame shape, and the peripheral edge of the diaphragm 2 is inserted and connected to a groove having a U-shaped cross section formed over the entire length of the inner peripheral part. After that, the two foam resin plates 3 on the front and back,
An elongated tape-shaped elastic support piece 8 is interposed around the entire circumference of the stepped portion formed on the adhesion surface of 4, and the diaphragm 2 is supported by the frame 7 by this elastic support piece 8. ing.

(Effects of the Invention) Since the flat speaker of the present invention does not require lead wires,
Naturally, the work of soldering the lead wires to the piezoelectric sounding body and the work of soldering the lead wires to the relay board becomes unnecessary, improving productivity.

The metal foil is wired to pass through the protrusion of the foam resin board, and the metal foils on each foam resin board do not come into contact with each other, so there is no risk of chattering noise, so an elastic adhesive such as silicone is used. There is no need for coating, which improves productivity.

In addition, metal foil wiring is made by pasting one side of the metal foil with adhesive on a predetermined position on a foamed resin board, so compared to lead wire wiring, the work is easier and requires less skill. do not.

Furthermore, according to the present invention, a relay board itself for relaying to an external cable is not required.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention. 2 and 3 are plan views showing a state in which metal foil is wired on the opposite side of a foam resin board used in an embodiment of the present invention, and FIG. 3 shows the foamed resin plate on the rear side. FIG. 4 is a plan view showing a conventional example, and FIG. 5 is an enlarged sectional view of a main part of the conventional example. 1-... Piezoelectric sounding body, 1a... Metal plate, 1b... Piezoelectric plate, 2... Vibration plate, 3.4... Foamed resin plate, 3a, 4a... Projection, 3b, 4b... Recessed portion, 5a... + side metal foil, 5b... - side metal foil, 6... Conductive adhesive, 7... Frame, 8... Elastic support piece, 9... -Lead wire, 10...Elastic adhesive, 11...Relay board.

Claims (1)

[Scope of Claims] Two foamed resin plates each having a concave portion formed on the main surface are pasted together such that the concave portions face each other, and a piezoelectric sounding element is formed within the concave portion by a protrusion within the concave portion. In the planar speaker in which the center portion of the piezoelectric sounding body is sandwiched, a metal foil is wired on each opposing surface of the two foamed resin plates so as to pass through at least the protrusion, and a conductive wire is wired between the piezoelectric sounding body and the metal foil. A flat speaker characterized in that a piezoelectric sounding element and metal foil are electrically connected with an adhesive.