JPH0453007Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention can be used as a detection element that converts bending deformation, pressure, etc. into an electrical signal and outputs it, or as a vibrator that vibrates by applying a variable voltage. The present invention relates to a piezoelectric element, and more particularly to a piezoelectric element in which electrodes are formed on both sides of a piezoelectric film.

[Conventional technology]

Conventional piezoelectric elements of this type are made of ceramics,
It has a structure in which electrodes made of metal such as silver, aluminum, copper, etc. are formed by vapor deposition or the like on both sides of a polymeric piezoelectric film.

[Problem that the invention attempts to solve]

However, for such piezoelectric elements,
Since the electrodes lack elasticity, if a large displacement is applied to the element or an AC voltage is applied to both electrodes of the piezoelectric film 1 to cause the element to vibrate with a large amplitude, the electrodes will break and become unusable. It was hot.

[Summary of the idea]

In order to solve the above-mentioned problems, the device of the present invention has a stretchable conductive paint layer 3 formed by dispersing conductive powder, fibers, etc. in epoxy resin on the electrode 2 of the piezoelectric film 1 as shown in the figure. It is formed and constructed.

With such a configuration, the conductive paint layer 3
has elasticity, so the electrodes 2 and 2 can be moved by applying a large displacement to the element, or by applying an alternating current voltage between the electrodes 2 and 2 of the piezoelectric film 1 or between the electrodes 2 and 2a to vibrate the element with a large amplitude. Even if 2a breaks, or even if the electrodes 2, 2 are cut in advance, the electrodes 2, 2a will remain electrically connected by the conductive paint layer 3, and there is no risk of them becoming unusable. , the range of use can be expanded.

[Specific explanation of the idea]

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

FIG. 1 is a cross-sectional view showing one embodiment of the device of the present invention. In this embodiment, film-like electrodes 2 made of aluminum or the like are formed by vapor deposition or the like on both sides of a piezoelectric film 1 made of ceramic or polymer. , a conductive paint layer 3 having stretchability is formed on both electrodes 2, 2. 5a, 5
b is a lead wire connected to both electrodes 2,2.

The elastic conductive paint layer 3 is formed by coating (spraying, It can be easily formed by coating, brushing).

Since this embodiment has the above-mentioned configuration, the elasticity of the conductive paint layer 3 can cause large deformations to the element, and an AC voltage can be applied between both electrodes 2 of the piezoelectric film 1 to cause the element to have a large amplitude. Even if the electrode 2 is broken by vibrating it, especially by making it vibrate in resonance, or even if the electrode 2 is broken in advance, the electrode 2 is maintained in an electrically connected state by the conductive paint layer 3, There is no risk of the device becoming unusable, and the range of use can be expanded.

FIG. 2 is a sectional view showing another embodiment. In this embodiment, two piezoelectric films 1, 1 are bonded together, and a membrane electrode 2a is provided on the bonded surface and both outer surfaces.
2, a flexible shim 4 such as phosphor bronze or a stretchable conductive paint layer is formed on the bonding surface, and a stretchable conductive paint layer 3 is formed on the membrane electrodes 2 on both outer surfaces. It will be formed.

The embodiment shown in Fig. 1 above is applied to a single-layer piezoelectric element, but the embodiment shown in Fig. 2 is applied to a laminated piezoelectric element, and the output signal can be increased or the amplitude This is preferable because it allows you to obtain

As described above, according to the present invention, the electrode 2 of the piezoelectric film 1 is formed with a stretchable conductive paint layer 3 made of an epoxy resin dispersed with conductive powder, fibers, etc.; The electrode 2 may be broken by applying a large displacement to the element due to the elasticity of the conductive paint layer 3, or by applying an AC voltage between the electrodes 2 and 2 or between the electrodes 2 and 2a of the piezoelectric film 1 to vibrate the element with a large amplitude. Even if the electrode 2 is broken in advance, the electrode 2 will remain electrically connected by the conductive paint layer 3, and there is no risk of it becoming unusable.
The scope of use can be expanded. In addition, since the elasticity is improved, the amplitude can be increased.

Note that if the electrode 2 is broken in advance, it will not break during use, so stable performance can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the device of the present invention;
FIG. 2 is a sectional view showing another embodiment. 1... Piezoelectric film, 2, 2a... Electrode, 3... Conductive paint layer.

Claims (1)

[Scope of utility model registration request] A piezoelectric element is constructed by forming a stretchable conductive paint layer, which is made by dispersing conductive powder, fibers, etc. in epoxy resin, on the electrode of a piezoelectric film.