JPH0352078Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to the structure of a piezoelectric electroacoustic transducer that uses a diaphragm to which a piezoelectric material is attached, and in particular, the structure of a piezoelectric electroacoustic transducer that uses a diaphragm to which a piezoelectric material is attached. The present invention relates to a piezoelectric electroacoustic transducer that is inexpensive and has high reliability as an electrical connection means.

[Problems that conventional techniques and ideas attempt to solve]

As a conventional electro-acoustic transducer of this type,
There is an electroacoustic transducer shown in Japanese Patent No. 34239, which will be explained with reference to FIG. Figure 3a
is a diaphragm, b is a terminal plate, and c is a cross-sectional view of the above-mentioned a and b stacked together. In FIG. 3, 1 is a diaphragm made of a metal material, 2 is a piezoelectric material, 3 is an electrode provided on both sides of the piezoelectric material 2, 4 is an insulating layer, and 5 is provided on a part of the insulating layer. A conductive layer, 6 is a terminal board, 6-1 and 6-2 are conductive patterns provided on the terminal board, and 7-1 and 7-2 are terminals in contact with the conductive patterns 6-1 and 6-2. be. In this structure, a printed wiring board is used as the terminal board 6, and the terminals 7-1, 7-2 and the conductive patterns 6-1, 6-2 are joined by soldering. On the other hand, the conductive patterns 6-1 and 6-2 were plated with noble metal, solder, etc. on the copper foil in order to ensure the reliability of the bonding. d in Figure 3
is a cross-sectional view showing the crimping state between the conductive layer 5 on the diaphragm side and the conductive pattern 6-2 on the terminal board.
The pattern edges of the diaphragm 1 become thick, which causes the insulating layer 4 to be destroyed and a short circuit between the diaphragm 1 and the conductive pattern 6-2 to occur. Furthermore, there is a drawback that it is difficult to flow solder the entire surface of the solder during solder bonding.

In addition, these plating processes are expensive because they are based on wet plating methods, and the inability to perform flow soldering has also led to an increase in prices.

[Means for solving problems]

The present invention solves the above-mentioned problems and provides a highly reliable and inexpensive piezoelectric electroacoustic transducer. A piezoelectric electroacoustic transducer comprising a piezoelectric vibrator attached to a vibrating substrate and a terminal board having two external terminals respectively connected to the pair of electrodes, wherein the terminal board is a printed wiring board and the terminal board is a printed wiring board. the piezoelectric vibrator and the terminal plate are stacked together to form an electrical connection. Features.

[Effect]

The piezoelectric electroacoustic transducer of the present invention has a structure in which the terminal board is coated with a carbon pattern after patterning the printed wiring board, thereby reducing the level difference of the conductive pattern on the terminal board.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and FIG. , 4 is an insulating layer, and 5 is a conductive layer made of carbon paint or the like. Figure b is a plan view of terminal boards stacked facing the diaphragm, in which 6 is a terminal board made of a printed wiring board, 6-1 and 6-2 are copper foil patterns, and 8-1 and 8- 2 is the copper foil pattern 6
This is a carbon pattern formed on -1 and 6-2 by screen printing using carbon paint. Figure c is a partial sectional view when the diaphragm and the terminal board are stacked.

In such a structure, the copper foil pattern 6-1,
6-2 has a thickness of 35 μm, but the carbon patterns 8-1 and 8-2 have a thickness of about 10 to 15 μm, and the coating film hardness is generally soft, about 2 to 4 H on a pencil hardness, and the conductive By making the pattern 8-2 on the terminal board side facing and in contact with the layer 5 only a carbon pattern, the insulating layer 4 is not destroyed and the risk of short circuit is eliminated. Furthermore, carbon paint has corrosion resistance, moisture resistance, and heat resistance, and not only provides high reliability, but also works as a solder resist when soldering the terminal board 6, so it can be used in general flow soldering. There are also advantages that can be achieved through legislation.

FIG. 2 shows another embodiment of the present invention, in which the copper foil patterns 6-1 and 6-2 are disposed close to the outer periphery of the terminal board, and the conductive layer 5 as shown in FIG. In this state, the copper foil pattern 6-2 exists at the contact portion between the carbon pattern 8-2 and the carbon pattern 8-2. c.
The figure is a cross-sectional view of figure b viewed along the circumferential direction of the terminal board, and the end of the copper foil pattern 6-2 is widely covered with the carbon pattern 8-2, so there is a step difference at the end. Since the carbon pattern 8-2 is gently inclined, the insulating layer is no longer destroyed when it is pressed against the diaphragm.

Carbon patterns can be easily formed by dry methods such as screen printing, and flow soldering is also possible, making it possible to create inexpensive piezoelectric electroacoustic transducers.

[Effect of idea]

As explained above, since the terminal board is coated with a carbon pattern after patterning the printed wiring board, it has the advantage of providing a highly reliable and inexpensive piezoelectric electroacoustic transducer.

[Brief explanation of drawings]

Fig. 1 shows a piezoelectric electroacoustic transducer as one embodiment of the present invention, Fig. 2 shows a piezoelectric electroacoustic transducer as another embodiment of the invention, and Fig. 3 shows a conventional piezoelectric electroacoustic transducer. An example of an acoustic transducer is shown. 1: Vibration plate, 2: Piezoelectric body, 4: Insulating layer, 5: Conductive layer, 6: Terminal plate, 6-1, 6-2: Copper foil pattern, 8-1, 8-2: Carbon pattern.

Claims (1)

[Scope of utility model registration request] A piezoelectric vibrator comprising a piezoelectric vibrator in which one electrode of a piezoelectric material having a pair of electrodes on both sides is attached to a metal vibrating substrate, and a terminal board having two external terminals each connected to the pair of electrodes. In the type electroacoustic transducer, the terminal board is a printed wiring board and includes a pair of copper foil patterns and a carbon pattern in which the copper foil patterns are partially covered with carbon resin paint, and A piezoelectric electroacoustic transducer characterized in that an electrical connection is made by stacking and bonding with the terminal plate.