JPH04165796A - Planar speaker - Google Patents

Abstract

PURPOSE:To dispense with soldering of lead wire to a repeater substrate and to improve productivity by electrically connecting one of two pieces of metal foil arranged on each opposing surfaces of two foamed resin plates to a metal plate through a through hole in a piezoelectric plate and electrically connecting two piezoelectric plates with a lead wire. CONSTITUTION:Piezoelectric plates 1b and 1b' are made concentrically adhere to both sides of a metal plate 1a. Since the piezoelectric plate 1b, which is one of two piezoelectric plates, has a through hole in the center, the center of the metal plate 1a is exposed on its adhering side. Metal foil 5a on a positive side is electrically connected to the center of the piezoelectric plate 1b atop a projecting part 3a through an conducting adhesive material 6 while metal foil 5b on a negative side is electrically connected to the center of the metal plate 1a atop a projecting part 4a through the conducting adhesive material 6. The centers of the two piezoelectric plates 1b and 1b' are mutually connected via a lead wire 10, and both ends of the lead wire 10 are soldered to the peripheries of the piezoelectric plates 1b and 1b'. Thus work for soldering a lead wire to a repeating substrate can be dispensed with, and productivity improves.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a planar speaker using a bimorph piezoelectric sounding body.

(Prior Art) The general structure of a flat speaker using a bimorph piezoelectric sounding body includes a plurality of recesses 3b on the main surface.

4b formed on two foamed resin plates 3, 4 or each recess 3
b and 4b are pasted together so as to face each other, and the center portion of the piezoelectric sounding body 1 is held between the projections 3a and 4a in each of the recesses 3b and 4b within the plurality of recesses 3b and 4b. There is.

As shown in FIG. 5, each piezoelectric sounding body 1 includes a circular metal plate 1a and two circular piezoelectric plates 1 having a smaller diameter than the circular metal plate 1a.
b, lc (for example, made of PZT), and the metal plate 1
Piezoelectric bodies 1b and lc are coaxially attached to both sides of metal plate 1a and piezoelectric plates 1b and lc.
Lead wires 10 are soldered to the electrodes on the surface side of the electrode, and in order to prevent these lead wires 10 from coming into contact with each other,
An elastic adhesive 11 such as silicone is applied.

The lead wires 10 soldered to the electrodes of the metal plate 1a and the piezoelectric plates 1b, lc are wired between the opposing surfaces of the two foamed resin plates 3.4, as shown in FIG. 6, and are connected to external cables. It is soldered to a relay board 12 for relaying.

(Problems to be Solved by the Invention) In the conventional planar speaker described above, the lead wire is drawn out from the outer periphery of the metal plate and the piezoelectric plate that constitute the piezoelectric sounding body. By the way, since this outer periphery is the part with the largest amplitude, the three lead wires soldered to the piezoelectric sounding element vibrate and come into contact with each other, producing a chattering sound.
Sound quality deteriorates. 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. Furthermore, it is difficult to equalize both the amount and state of application of the elastic adhesive, and there is a problem that the sound quality is not constant.

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. A piezoelectric sounding body is held between the protrusions in the recess, and this piezoelectric sounding body consists of a metal plate and piezoelectric plates attached to both the front and back sides of this metal plate, and one piezoelectric body has a through hole in its center. 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 adhesive is interposed between the piezoelectric sounding body and the metal foil. , one of the metal foils is electrically connected to the metal plate through the through hole of the piezoelectric plate, the other metal foil is electrically connected to the electrode of the piezoelectric plate, and the piezoelectric plates are connected to each other by lead wires. It is characterized by being electrically connected.

(Function) Since the flat speaker according to the present invention has metal foil wired on the opposing surface of the foamed resin board, soldering work to the relay board,
Also, there is no need to apply an 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 foamed resin plates 3 and 4 have a rectangular shape, but the foamed resin plate 3 on the front side is slightly larger than the foamed resin plate 4 on the rear side, and a stepped portion is formed on the bonding surface of both. . Foamed resin board 3
．． A plurality of recesses 3b and 4b are formed on the opposing surfaces of 4, respectively, and within these recesses 3b and 4b, each recess 3b
, a plurality of piezoelectric sounding bodies l by the protrusions 3a and 3b in 4b.
The central parts of the two are held together.

3 and 4 are plan views showing opposing surfaces of the foamed resin plates 3 and 4 used in the present invention, with FIG. 3 showing the foamed resin plate 3 on the front side, and FIG. A resin plate 4 is shown.

The plurality of recesses 3b,
4b and protrusions 3a, 4a are formed, respectively. In this embodiment, for example, a total of nine recesses 3b, 4b in three vertical rows and three horizontal rows are formed, and these nine recesses 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 attached in three horizontal rows so as to pass through the apexes of 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

Note that the metal foils 5a and 5b are plastic tapes 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 further improves workability. improves.

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 foamed resin plates 3 and 4 are pasted together to face each other, and the + side metal foil 5 is placed on the top of the protrusion.
A conductive adhesive 6 is applied to the opposing surfaces of the metal foil 5b and the metal foil 5b. is fixed between the projections 3a and 4b.

The piezoelectric sounding body 1 consists of piezoelectric plates 1b+, lc (for example, made of PZT, etc.) smaller in diameter than the circular metal plate 1a on one side, and piezoelectric plates 1b, lc concentrically arranged on both sides of the metal plate 1a. One of the piezoelectric plate ICs has a concentric circular through hole in its center, so the center part is exposed on the side where the metal plate IC is attached. There is. The + side metal foil 5a is electrically connected to the center of the piezoelectric plate 1b via the conductive adhesive 6 on the apex of the protrusion 3b, and the - side metal foil 5b is connected to the center of the piezoelectric plate 1b on the apex of the protrusion 4b. On the apex, it is electrically connected to the center of the metal plate 1a via a conductive adhesive 6. The two piezoelectric plates 1b, lc are connected to each other by lead wires, and both ends of the lead wires are soldered to the outer peripheries of the piezoelectric plates 1b, lc, respectively.

In order to prevent chattering noise caused by the lead wires connected to the piezoelectric plates 1b and lc, an insulating tape 7 is attached to cover the lead wires.

A frame 8 is provided on the peripheral edge of the diaphragm 2 to cover it. The frame 8 has a picture frame shape, and the peripheral edge of the diaphragm 2 is inserted and connected into a groove having an opening-shaped cross section formed over the entire length of the inner peripheral part. In addition, two foam resin plates 3, front and rear,
An elongated tape-shaped elastic support piece 9 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 8 by this elastic support piece 9. ing.

(Effects of the Invention) In the flat speaker of the present invention, since the metal foil is wired on the opposing surface of the foamed resin board, there is no need to solder the wires to the relay board, improving productivity.

The metal foil is wired to pass through the protrusion of the foamed resin board, and the metal foils on each foamed resin board do not come into contact with each other, so there is no risk of chattering noise, so elastic adhesives such as silicone are used. There is no need to apply chemicals, improving 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 necessary.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention. FIG. 2 is a sectional view showing essential parts of an embodiment of the present invention. 3 and 4 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. FIG. 4 shows the foamed resin plate on the rear side. FIG. 5 is a sectional view showing the main parts of the conventional example, and FIG. 6 is a plan view showing the conventional example. DESCRIPTION OF SYMBOLS 1... Piezoelectric sounding body, 1a... Metal plate, lb, IC... Piezoelectric plate, 2... Vibration plate, 3.4... Foamed resin board, 3a, 4a... Protrusion part, 3b, 4b... recess, 5a... + side metal foil, 5b... - side metal foil, 6... conductive adhesive, 7... insulating tape 8... frame, 9. ...Elastic support piece, 10...Lead wire, 11...Elastic adhesive, 12...Relay board.

Claims (1)

[Claims] Two foamed resin plates each having a concave portion formed on the main surface are pasted together so that the concave portions face each other, and within the concave portion, a piezoelectric sounding body is held between the protrusions within the concave portion, and the piezoelectric The sounding body consists of a metal plate and a piezoelectric plate attached to both the front and back sides of the metal plate, one piezoelectric plate has a through hole formed in its center, and each of the opposing surfaces of the two foamed resin plates A metal foil is wired so as to pass through at least the protrusion, a conductive adhesive is interposed between the piezoelectric sounding body and the metal foil, and one of the metal foils is wired through the through hole of the one piezoelectric plate. The piezoelectric body is electrically connected to the metal plate, the other side of the metal foil is electrically connected to the electrode of the other piezoelectric body, and the piezoelectric bodies are electrically connected to each other by lead wires. flat speaker.