JP6163624B2 - Piezoelectric element - Google Patents

Description

      For the purpose of improving power generation efficiency, the present invention provides a piezoelectric film formed by alternately laminating a plurality of thermoplastic piezoelectric materials and a thermoplastic elastomer having rubber elasticity, and a hollow dome-shaped protrusion is provided on the piezoelectric film. The present invention relates to a piezoelectric element.

Most digital home appliances have to pursue the contradictory nature of high performance and light and thin at the same time, so the components that make up digital home appliances are being mounted with higher density. . On the other hand, since operation at a higher frequency is required, it always suffers from generation of noise and heat. One of the key technologies to solve this problem is the piezoelectric device. In addition to the expansion of the original market, the use of the electromagnetic type has been expanded by the replacement of the market where the electromagnetic type has been the mainstream and the development of completely new applications that have never existed before It is expected to continue.
A piezoelectric element is a device that uses a piezoelectric material that generates a voltage proportional to the strain at both ends of the crystal when strain is applied to the crystal, and a force or strain that is proportional to the voltage when a voltage is applied ( (Objects with a certain structural function for the purpose of using various phenomena), there are disposable lighters in familiar things, and when you press the lever, it will make a sound with a `` click '' sound and ceramic Piezoelectric elements are used. When a “click” sound is heard, the compressed piezoelectric element is returned to its original state by a spring, and sparks are ignited by the voltage generated at that time. Piezoelectric elements are also used for sensors, melody telegrams, electronic buzzers, etc. that are attached to window glass for crime prevention. Piezoelectric devices have a simple structure and can be mass-produced, do not generate noise during rotation, do not require magnetism like electromagnetic induction, can generate electricity with only mechanical vibration energy, and even wiring must be mistaken For example, power can be generated with good reproducibility and reliably, power can be generated without preparation anytime and anywhere as long as the piezoelectric element is not broken, and so on.

Piezoelectric materials include single crystal (hexagonal) crystals such as quartz, polycrystalline ceramics of lead zirconate titanate, and thermoplastics. Crystals, ceramics, and plastics have their own characteristics. So it is properly used according to the application.
A crystal device such as a crystal resonator is excellent in temperature stability and has a very high frequency accuracy, so that it is used as a high-precision oscillator such as a wireless device such as a mobile phone that requires frequency accuracy and a CPU clock.
Piezoelectric ceramics have a high electromechanical conversion rate and can easily create various shapes, so there are many resonance modes determined by the shape and the direction of polarization, and each resonance mode has its own resonance frequency and piezoelectric characteristics and is free of characteristics. Because of its high degree, it is used as an ultrasonic transducer in piezoelectric transformers, piezoelectric speakers, ultrasonic motors, and fish detectors.
Piezoelectric plastics are easy to process and have a large-area thin film, high voltage output more than 10 times that of piezoceramics, dynamic range: wide pressure sensitivity of 140dB, wide frequency characteristics from 0.001 Hz to megahertz, and excellent It has chemical stability and is light and soft, so it can be used for microphones, headphones, laser power meters, infrared sensors, speakers and other actuators (elements that change external stimuli into simple movements), medical ultrasonic diagnostic elements, and pressure power generation. In recent years, applications for bending artificial muscles and robot joints have also been studied.

    Piezoelectric material refers to a substance that generates a voltage when deformed, and a substance that deforms when a voltage is applied. However, the deformation is mainly a bending or distortion of the substance. Plastic piezoelectric elements have been the mainstream, but the electromotive force of piezoelectric devices laid on the girder of pressure power generation mats and highway overpasses is mostly due to weighting from above, so the bending and distortion of piezoelectric elements Therefore, the improvement of the plastic piezoelectric element is desired in order to improve the power generation efficiency. In recent years, with the improvement of printing technology, the production of plastic piezoelectric elements has become an object, and mass production of low-cost plastic piezoelectric elements has become possible. Has been replaced, and the market is progressing, so further technological innovation is expected, including the appearance of newly developed plastic piezoelectric elements.

      In the present invention, for the purpose of improving the piezoelectric efficiency of the plastic piezoelectric element, a plurality of layers are formed by sandwiching a film in which an electrode is provided on a thermoplastic material, which is a piezoelectric material, with a film of a thermoplastic elastomer each having a resilience characteristic. We have developed a plastic piezoelectric element that is stacked and partly hollow projections.

      A piezoelectric piezoelectric element is made by laminating multiple layers of a piezoelectric elastomer film with electrodes, sandwiched between thermoplastic elastomer films each having rebound resilience, and with some hollow projections. By using it as a piezoelectric actuator for a piezoelectric power generation device, deformation / bending distortion due to weighted pressurization increases and power generation can be performed more efficiently.

It is a side view of the Example of this invention plastic piezoelectric element. It is a top view of the Example of this invention plastic piezoelectric element. It is a front view of the Example of this invention plastic piezoelectric element. 3 is an exploded view of the plastic piezoelectric element of the fifth layer is a buffer material TPEE film for the fifth layer coating 3 is an exploded view of the plastic piezoelectric element of the fourth layer is a fourth layer piezoelectric material PVDF film 3 is an exploded view of the plastic piezoelectric element of the third layer is a third layer cushioning material TPEE film 3 is an exploded view of the plastic piezoelectric element of the second layer is a second layer piezoelectric material PVDF film 3 is an exploded view of the plastic piezoelectric element of FIG. 3 is a cut view of the buffer material TPEE film for the first layer substrate. 8 is an exploded view of the plastic piezoelectric element is a side view of a cut view of the first layer base cushioning material TPEE film. Structural diagram of a piezoelectric device fitted with two plastic piezoelectric elements sandwiching a repulsion 17 from above and below

Piezoelectric material refers to a substance that generates a voltage when deformed, or a substance that deforms when a voltage is applied. An element formed by attaching an electrode to the piezoelectric material to allow electrical input or output is a piezoelectric element. It is.
Thermoplastics are composed of chain polymers, which literally are plastics that are soft and easy to process when heated and harden when cooled. Thermoplastics also have piezoelectric materials. Generally, polyvinylidene fluoride (hereinafter referred to as PVDF) is used. Fluorine pulls electrons and becomes negative, and other parts become positive. Such an electrical bias is called polarization. When the PVDF film is stretched and the molecular chain is stretched, the direction of polarization is also aligned. Then, the adjacent molecules are also arranged by being influenced by the polarization, so that the whole molecules are arranged, and such a material in which the polarization is spontaneously arranged is called a ferroelectric material. For example, if an electrode is attached to an oriented PVDF film and bent, the alignment of the polymer polarization also changes, so that a weak voltage is generated. Conversely, when a voltage is applied, the PVDF film is bent by repulsion and repulsion. An element that changes an external stimulus (voltage in this case) into a simple movement is called an actuator. The PVDF molding method is extrusion and injection, and the characteristics are bending resistance, impact resistance, light weight, and flexibility.
Thermoplastic elastomer is a name for a group of materials with rubber elasticity in the structure, and there is no cross-linking between molecular chains, but flexible soft segments connect molecular chains in which rigid hard segments are arranged. It has rubber elasticity at normal temperature and plasticizes at high temperature. The thermoplastic elastomer polyester (hereinafter referred to as TPEE) molding method is extrusion and injection, and the characteristics are impact resilience, bending fatigue resistance, durability, oil resistance, chemical resistance, and heat resistance.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the embodiment of a plastic piezoelectric element according to the present invention will be described in detail with reference to the accompanying drawings. In order to explain the embodiment of the plastic piezoelectric element, PVDF was used as a plastic piezoelectric film and TPEE was used as a buffer material film as a raw material for producing the plastic piezoelectric element.
FIG. 1 is a side view of a first embodiment of the plastic piezoelectric element 1 according to the present invention, in which five layers are stacked and a hollow protrusion (a semicircular dome shape in this embodiment) 2 is formed in the center, and a fourth layer piezoelectric material is formed in the lower portion. An electrode 3 of the PVDF film 9 and an electrode 5 of the second layer piezoelectric material PVDF film 13 are provided. FIG. 2 is a plan view of the first embodiment of the plastic piezoelectric element 1 of the present invention, which includes a hollow protrusion 2 at the center and electrodes 3 and 4 of a fourth-layer piezoelectric material PVDF film 9 at the bottom. FIG. 3 is a front view of the first embodiment of the plastic piezoelectric element of the present invention, which is laminated in five layers and has a hollow protrusion 2 in the center and a fourth layer of the piezoelectric material PVDF film 9 in the front and a third layer of electrodes 3 and 4 Electrodes 5 and 6 of the piezoelectric material PVDF film 13 are provided. FIG. 4 is an exploded explanatory view of the plastic piezoelectric element shown in FIG. 3 and is a fifth layer covering cushioning material TPEE film 7, which has a hollow protrusion in the center and a plastic piezoelectric element body 1 and a protrusion 2 in the center in the plan view of FIG. Share the appearance with. FIG. 5 is an exploded explanatory view of the plastic piezoelectric element in FIG. 3 and is a fourth-layer piezoelectric material PVDF film 9 having a hollow projection 8, an electrode 3 and an electrode 4 at the center. FIG. 6 is an exploded explanatory view of the plastic piezoelectric element shown in FIG. 3 and is a third layer cushioning material TPEE film 11 having a hollow protrusion 10 in the center. FIG. 7 is an exploded explanatory view of the plastic piezoelectric element in FIG. 3 and is a second layer piezoelectric material PVDF film 13 having a hollow projection 12, an electrode 5 and an electrode 6 at the center. FIG. 8 is an exploded explanatory view of the plastic piezoelectric element shown in FIG. 3. FIG. 8 is a cross-sectional view of the first layer base cushioning material TPEE film 15, which has a hollow protrusion 14 in the center. FIG. 9 is an exploded explanatory view of the plastic piezoelectric element of FIG. 8. FIG. 9 is a side view of a cross section obtained by cutting the first layer base cushioning material TPEE film 15 and the hollow projection 14 at the center along the alternate long and short dash line 16.

As long as the gist of the same invention is not violated, another embodiment of the present invention is possible.
FIG. 10 shows an effective embodiment 2 of the plastic piezoelectric element of the present invention. In the use of the plastic piezoelectric element of the present invention, bending or distortion due to pressure from above is restored by the rubber elasticity provided in the plastic piezoelectric element of the present invention. At the same time, a repulsive material (in this example, a hollow ball of TPEE) 17 was inserted and fitted in order to assist the restoring force to return to the original state of the plastic piezoelectric element of the present invention. Furthermore, the piezoelectric device in which the repulsion object 17 is sandwiched from above and below by two plastic piezoelectric elements of the present invention can efficiently use energy generated by pressurization from both the top and bottom directions for power generation.

      Electromotive force of piezoelectric elements laid on the mat for pressure power generation and bridge girder of highway overpass is mostly due to weight from above, so the piezoelectric device is improved because there is little bending and distortion of piezoelectric device and power generation efficiency is not good Is expected. A piezoelectric piezoelectric element is formed by laminating a plurality of layers, each of which is formed by sandwiching a film of thermoplastic elastomer, which is a piezoelectric material, with a thermoplastic elastomer film characterized by rebound resilience. By creating it and using it as a piezoelectric actuator for a piezoelectric power generation device, the deformation, bending, and strain due to weighted pressurization increase and power can be generated efficiently.

1 Piezoelectric element body 2 Hollow protrusion
3 Electrode 4 Electrode 5 Electrode 6 Electrode 7 Buffer material TPEE film 8 Hollow protrusion 9 Piezoelectric material PVDF film 10 Hollow protrusion 11 Buffer material TPEE film 12 Hollow protrusion 13 Piezoelectric material PVDF film 14 Hollow protrusion 15 Buffer material TPEE film 16 Dotted line 17 TPEE ball

Claims (2)

Using the rebound resilience, a characteristic of any thermoplastic elastomer, to reinforce the resilience of the thermoplastic thermoplastic resin, the thermoplastic elastomer film and the thermoplastic thermoplastic film are alternately laminated repeatedly. In order to use a piezoelectric plastic film, which is a multi-layer integrated type, as a piezoelectric element, electrodes are applied to thermoplastic films of all piezoelectric materials among the alternately and repeatedly laminated films. In order to increase the deformation of the plastic piezoelectric element due to external pressurization, a hollow protrusion is arbitrarily provided in the prepared plastic piezoelectric element, and the impact resilience of the plastic piezoelectric element is enhanced inside the hollow protrusion. Piezoelectric device characterized by fitting padding having rebound resilience for the purpose Using the rebound resilience, a characteristic of any thermoplastic elastomer, to reinforce the resilience of the thermoplastic thermoplastic resin, the thermoplastic elastomer film and the thermoplastic thermoplastic film are alternately laminated repeatedly. In order to use a piezoelectric plastic film, which is a multi-layer integrated type, as a piezoelectric element, electrodes are applied to thermoplastic films of all piezoelectric materials among the alternately and repeatedly laminated films. Two plastic piezoelectric elements that are arbitrarily provided with hollow protrusions are used to increase the deformation of the plastic piezoelectric elements due to external pressure, and the inside of the hollow protrusions are faced to each other. For the purpose of strengthening the resilience of the two plastic piezoelectric elements. A piezoelectric device, characterized in that fitted stuffed with elasticity

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