阅读说明：本技术 一种压电系数测量装置 (Piezoelectric coefficient measuring device ) 是由 陈显锋 于 2019-09-05 设计创作，主要内容包括：本发明公开了一种压电系数测量装置,包括加力装置、探针、信号处理装置,所述加力装置包括金属接触结构、弹性结构和非极性绝缘结构,所述金属接触结构与压电薄膜材料接触,并对压电薄膜材料施加压力,所述金属接触结构、探针、信号处理装置与压电薄膜材料形成导电回路。由于金属材料具有较好的刚性,因此可以保证在加力的情况下,即使接触面积比较小,金属接触结构也不会发生变形,可长时间使用。(The invention discloses a piezoelectric coefficient measuring device which comprises a force applying device, a probe and a signal processing device, wherein the force applying device comprises a metal contact structure, an elastic structure and a nonpolar insulating structure, the metal contact structure is in contact with a piezoelectric film material and applies pressure to the piezoelectric film material, and the metal contact structure, the probe, the signal processing device and the piezoelectric film material form a conductive loop. Because the metal material has better rigidity, the metal contact structure can not deform even if the contact area is smaller under the condition of applying force, and can be used for a long time.)

1. The piezoelectric coefficient measuring device is characterized in that the force applying device comprises a metal contact structure, an elastic structure and a non-polar insulating structure, the metal contact structure is in contact with a piezoelectric thin film material and applies pressure to the piezoelectric thin film material, and the metal contact structure, the probe, the signal processing device and the piezoelectric thin film material form a conductive loop.

2. The device for measuring piezoelectric coefficient according to claim 1, wherein the contact surface of the metal contact structure with the piezoelectric thin film material is a plane, and the metal contact structure is made of metal.

3. the device of claim 1, wherein the resilient structure is disposed between the metal contact structure and the non-polar insulating structure; alternatively, the first and second electrodes may be,

The non-polar insulating structure is disposed between the metal contact structure and the resilient structure.

4. The device for measuring piezoelectric coefficient according to claim 1, wherein an area of a contact surface of the metal contact structure with the piezoelectric thin film material is smaller than a sectional area of the nonpolar insulating structure parallel to the contact surface.

5. A piezoelectric coefficient measuring apparatus according to any one of claims 1 to 4, wherein the nonpolar insulating structure is made of an organic nonpolar organic insulating material.

6. The device for measuring piezoelectric coefficient according to claim 5, wherein the organic non-polar organic insulating material is one or more of polytetrafluoroethylene, ethylene propylene diene monomer, polyethylene, polypropylene, styrene butadiene rubber, butyl rubber, butadiene rubber, parylene and polydimethylsiloxane.

7. A piezoelectric coefficient measuring apparatus according to any one of claims 1 to 4, wherein the nonpolar insulating structure is made of an inorganic nonpolar insulating material containing one or more elements of Si, Al, Mg, W, Sr, Ca, Cd, Ba, Ti, Ta, Nb, Cu, Fe, V, Co, Zr, C, B, N, and O.

8. the device according to claim 1, wherein the metal contact structure includes a connection portion and a contact portion, the contact portion is connected to the conductive thin film material, the connection portion is connected to the elastic structure or the nonpolar insulating structure, and a sectional area of the contact portion is smaller than a sectional area of the connection portion.

9. The device of claim 1, wherein the probe comprises a first probe in conductive communication with a first electrode of the piezoelectric film material, the metal contact structure is in conductive communication with a second electrode of the piezoelectric film material, and the signal processing device is connected to the first probe and the metal contact structure by wires to form a conductive loop.

10. The piezoelectric coefficient measuring apparatus according to claim 1, wherein the probe comprises a first probe and a second probe, the first probe is electrically connected to the first electrode of the piezoelectric thin film material, the second probe is electrically connected to the second electrode of the piezoelectric thin film material, and the signal processing means is connected to the first probe and the second probe by wires to form a conductive loop.

Technical Field

The invention relates to the field of piezoelectric coefficient measurement, in particular to a piezoelectric coefficient measuring device.

background

The piezoelectric coefficient measuring method of the piezoelectric material comprises the following steps: direct force measurements (Berlincourt method), laser interferometry (laser interferometer), laser Doppler vibrometers (laser scanning vibrometers) and Piezoelectric force microscopes (Piezoelectric force microscopes). The laser interferometry, the laser Doppler vibrometer and the piezoelectric force microscopy are all based on inverse piezoelectric effect, namely, a material generates deformation effect by adding a voltage signal, the piezoelectric coefficient is measured, the measurement precision is high, but the equipment is expensive, and the requirement on the measurement environment is high. The direct force application measurement method is a method for measuring a piezoelectric coefficient by using a direct piezoelectric effect, that is, a method for generating charges in a material by applying force, and although this method is not superior to the other 3 measurement methods in terms of measurement accuracy, the price of the measurement apparatus is low and the use and operation are simple.

The piezoelectric coefficient measuring device of the currently common stress measurement method, such as the measuring device of piezo test pte. ltd of the department of china and singapore, adopts the measuring device shown in fig. 1, clamps the sample 1 between two metal electrodes 21 by applying stress, the signal processing device 22 generates vibration by alternating signals, so that the stressed magnitude of the sample 1 is regularly changed, and records the relationship between the stressed magnitude change and the generated charge amount, thereby obtaining the d33 piezoelectric coefficient of the material. However, this measuring apparatus is only used for measuring the piezoelectric thin film material shown in fig. 2, and cannot measure the piezoelectric thin film material shown in fig. 3. The thickness of the piezoelectric film material shown in fig. 2 is more than 100 μm, and the electrodes 11 are located on both sides of the piezoelectric film 12. In the piezoelectric thin film material shown in fig. 3, the bottom of the piezoelectric thin film 12 is provided with a substrate 13, and the electrodes 11 are located on the same side of the substrate 13. The piezoelectric thin film material with the structure shown in fig. 3 has a large influence on the measurement result due to the existence of the substrate.

Patent 201721451425X discloses a piezoelectric coefficient measuring device, comprising a force application structure, an electrode contact structure for contacting a first electrode contact in a piezoelectric film sample, a connecting wire for connecting a substrate in the piezoelectric film sample, and a support platform, wherein the force application structure comprises a rigid portion and a contact portion, and the rigid portion is connected with the contact portion; the electrode contact structure comprises a contact part and a main rod, one end of the contact part is connected with one end of the main rod, the other section of the main rod is connected with an external electrical measurement system, and the connecting wire is connected with the external electrical measurement system. The patent proposes a method for measuring the piezoelectric coefficient of a thin film material by applying force to a sample from one side of the material by using an organic material with lower hardness as a contact part. However, such a measuring device has the following disadvantages:

(1) the hardness of the organic material is low, and the organic material is easy to deform or damage under the condition of small contact area, so that the contact head needs to be frequently replaced;

(2) Because the organic material is an insulating material, the contact head and the probe must be contacted with the same electrode at the same time to perform measurement, which undoubtedly increases the requirement for the contact area of the electrode, and limits the measurement environment.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a piezoelectric coefficient measuring device, wherein a force applying device is not easy to deform, the service life is long, the detection precision is high, and the damage to a piezoelectric film material is less.

The technical problem to be solved by the invention is that the force application device and the probe do not need to simultaneously contact the same electrode, and can be used for detecting piezoelectric thin film materials with small electrode areas.

In order to solve the technical problem, the invention provides a piezoelectric coefficient measuring device which comprises a force application device, a probe and a signal processing device, and is characterized in that the force application device comprises a metal contact structure, an elastic structure and a non-polar insulating structure, the metal contact structure is in contact with a piezoelectric film material and applies pressure to the piezoelectric film material, and the metal contact structure, the probe, the signal processing device and the piezoelectric film material form a conductive loop.

As an improvement of the above scheme, a contact surface between the metal contact structure and the piezoelectric thin film material is a plane, and the metal contact structure is made of metal.

As a modification of the above, the elastic structure is disposed between the metal contact structure and the non-polar insulating structure; alternatively, the first and second electrodes may be,

The non-polar insulating structure is disposed between the metal contact structure and the resilient structure.

As an improvement of the scheme, the area of the contact surface of the metal contact structure and the piezoelectric thin film material is smaller than the sectional area of the nonpolar insulation structure parallel to the contact surface.

As an improvement of the above solution, characterized in that the non-polar insulating structure is made of an organic non-polar organic insulating material.

As an improvement of the scheme, the organic nonpolar organic insulating material is one or more of polytetrafluoroethylene, ethylene propylene diene monomer, polyethylene, polypropylene, styrene butadiene rubber, butyl rubber, butadiene rubber, parylene and polydimethylsiloxane.

As an improvement of the above scheme, the non-polar insulating structure is made of an inorganic non-polar insulating material containing one or more elements of Si, Al, Mg, W, Sr, Ca, Cd, Ba, Ti, Ta, Nb, Cu, Fe, V, Co, Zr, C, B, N, and O.

as an improvement of the above scheme, the metal contact structure includes a connection portion and a contact portion, the contact portion is connected with the conductive film material, the connection portion is connected with the elastic structure or the nonpolar insulation structure, and a sectional area of the contact portion is smaller than a sectional area of the connection portion.

As an improvement of the above scheme, the probe comprises a first probe, the first probe is electrically connected with the first electrode of the piezoelectric film material, the metal contact structure is electrically connected with the second electrode of the piezoelectric film material, and the signal processing device is connected with the first probe and the metal contact structure through a lead to form a conductive loop.

as an improvement of the above scheme, the second probe is electrically connected with the second electrode of the piezoelectric film material, and the signal processing device is connected with the first probe and the second probe through leads to form a conductive loop.

The implementation of the invention has the following beneficial effects:

The invention provides a piezoelectric coefficient measuring device which comprises a force applying device, a probe and a signal processing device, wherein the force applying device comprises a metal contact structure, an elastic structure and a nonpolar insulating structure, the metal contact structure is in contact with a piezoelectric film material and applies pressure to the piezoelectric film material, and the metal contact structure, the probe, the signal processing device and the piezoelectric film material form a conductive loop. Because the metal material has better rigidity, the metal contact structure can not deform even if the contact area is smaller under the condition of applying force, and can be used for a long time.

In addition, the metal contact structure can uniformly transfer pressure to the piezoelectric film material, physical damage of the piezoelectric film caused by non-parallel contact and other reasons is avoided, and the surface of the metal contact structure does not need to be smooth.

Furthermore, the elastic structure can reduce the impact force of the metal contact structure when the metal contact structure is in contact with the piezoelectric film material, and the damage of the metal contact structure to the piezoelectric film material during measurement is avoided.

Furthermore, the nonpolar insulating structure can ensure that generated charges are gathered in a small space of the metal contact structure, prevent the diffusion of the charges, prevent the influence caused by the invasion of external charges, prevent the influence on the result caused by the self-polarization of the insulating material in the measuring process and ensure the accuracy of the result.

Finally, the metal contact structure of the present invention can be used as an electrical signal output terminal while applying a force, so that measurement can be performed even if the area of the second electrode is smaller than the area of the contact portion of the metal contact structure.

Drawings

FIG. 1 is a schematic structural diagram of a conventional piezoelectric coefficient measuring apparatus;

FIG. 2 is a schematic structural diagram of a first piezoelectric thin film material;

FIG. 3 is a schematic structural diagram of a second piezoelectric thin film material;

FIG. 4 is a schematic structural view of a first embodiment of the piezoelectric coefficient measuring apparatus of the present invention;

FIG. 5 is a schematic structural view of a first embodiment of the force applying means of the present invention;

FIG. 6 is a schematic structural view of a second embodiment of the force applying means of the present invention;

FIG. 7 is a schematic structural diagram of a first embodiment of a metal contact structure of the present invention;

FIG. 8 is a schematic structural diagram of a second embodiment of a metal contact structure of the present invention;

FIG. 9 is a schematic structural diagram of a third embodiment of a metal contact structure of the present invention;

Fig. 10 is a schematic structural view of a piezoelectric coefficient measuring apparatus according to a second embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 4, the piezoelectric coefficient measuring apparatus provided by the present invention includes a force application device, a probe 41, and a signal processing device 1.

Referring to fig. 5, the force applying device of the present invention includes a metal contact structure 31, an elastic structure 32, and a non-polar insulating structure 33, wherein the metal contact structure 31 is in contact with the piezoelectric thin film material 2 and applies pressure to the piezoelectric thin film material 2, and the metal contact structure 31, the probe 41, the signal processing device 1, and the piezoelectric thin film material 2 form a conductive loop. Preferably, the contact surface of the metal contact structure 31 and the piezoelectric thin film material 2 is a plane, and the material of the metal contact structure 31 is metal.

the metal contact structure of the force applying device is directly contacted with the piezoelectric film material, a certain pressure is applied to the piezoelectric film, and the metal material has better rigidity, so that the metal contact structure can not deform under the condition of applying force even if the contact area is smaller, and the force applying device can be used for a long time.

In addition, because the contact surface between the metal contact structure 31 and the piezoelectric thin film material 2 is a plane, the pressure can be uniformly transferred to the piezoelectric thin film material 2, thereby avoiding the physical damage of the piezoelectric thin film caused by non-parallel contact and the like, and the surface of the metal contact structure does not need to be smooth.

The elastic structure 32 of the present invention can reduce the impact force of the metal contact structure 31 when contacting the piezoelectric thin film material 2, and avoid the damage of the piezoelectric thin film material caused by the metal contact structure 31 during measurement.

In the measurement, the charge of the film material is changed by the application of forceThe chemical consumption is very small and is 10^-9C or less, any small disturbance is easy to cause deviation of the result, and the nonpolar insulating structure of the invention can ensure that the generated charges are gathered in a small space of the metal contact structure, prevent the diffusion of the charges and also prevent the influence caused by the invasion of external charges.

In addition, the nonpolar insulating structure can also prevent the influence on the result caused by the self-polarization of the insulating material in the measuring process, and ensure the accuracy of the result.

The sectional area of the nonpolar insulating structure 33 parallel to the contact surface of the metal contact structure and the piezoelectric film material is larger than the area of the contact surface of the metal contact structure and the piezoelectric film material, so that the service life of the nonpolar insulating structure can be ensured.

preferably, the non-polar insulating structure is made of an organic non-polar organic insulating material. The organic nonpolar organic insulating material is one or more of polytetrafluoroethylene, ethylene propylene diene monomer, polyethylene, polypropylene, styrene butadiene rubber, butyl rubber, butadiene rubber, parylene and polydimethylsiloxane.

Preferably, the non-polar insulating structure is made of an inorganic non-polar insulating material containing one or more elements of Si, Al, Mg, W, Sr, Ca, Cd, Ba, Ti, Ta, Nb, Cu, Fe, V, Co, Zr, C, B, N, and O.

In particular, the elastic structure 32 of the present invention is disposed between the metal contact structure 31 and the non-polar insulating structure 33. Preferably, the elastic structure 32 of the present invention is a spring or a leaf spring.

Referring to fig. 6, as another preferred embodiment of the force applying device of the present invention, the non-polar insulating structure 33 is disposed between the metal contact structure 31 and the elastic structure 32.

Referring to fig. 7 to 9, the metal contact structure 31 includes a connection portion 311 and a contact portion 312, the contact portion 312 is connected to the conductive film material, the connection portion 311 is connected to the elastic structure 32 or the non-polar insulating structure 33, and a cross-sectional area of the contact portion 312 is smaller than a cross-sectional area of the connection portion 311.

It should be noted that the piezoelectric thin-film material 2 includes a substrate 21, a piezoelectric thin-film layer 22, a first electrode 23, and a second electrode 24, and the first electrode 23 and the second electrode 24 are located on the same side.

Referring to fig. 4, the probe of the present invention comprises a first probe 41, the first probe 41 is electrically connected to the first electrode 23 of the piezoelectric film material, the metal contact structure 31 is electrically connected to the second electrode 24 of the piezoelectric film material, and the signal processing 1 device is connected to the first probe 41 and the metal contact structure 31 through wires to form a conductive loop.

The metal contact structure 31 of the present invention is made of a metal material and has a conductive property, so that the metal contact structure can be used as an electrical signal output terminal while applying a force, so that measurement can be performed even if the area of the second electrode 24 is smaller than that of the contact portion of the metal contact structure 31.

As another preferable embodiment of the piezoelectric coefficient measuring device according to the present invention, referring to fig. 10, the probe includes a first probe 41 and a second probe 42, the first probe 41 is electrically connected to the first electrode 23 of the piezoelectric thin film material, the second probe 42 is electrically connected to the second electrode 24 of the piezoelectric thin film material, and the signal processing device 1 is connected to the first probe 41 and the second probe 42 through a wire to form a conductive loop.

The signal processing device 1 of the invention generates vibration through alternating signals, so that the stress magnitude of the piezoelectric film material is regularly changed, and the relationship between the stress magnitude change and the generated charge quantity is recorded, thereby obtaining the d33 piezoelectric coefficient of the piezoelectric film material. The signal processing apparatus 1 of the present invention is a conventional device, and the present invention is not particularly limited.

The measuring method of the piezoelectric coefficient measuring device comprises the following steps:

Applying a certain pressure to the force applying device, compressing the elastic structure to generate a certain elastic force, transmitting the force to the tested piezoelectric film material, and recording the magnitude delta F of the applied force and the change delta Q of the charge quantity formed after the piezoelectric film material is stressed in a loop formed by the probe and the metal contact structure to obtain the d33 piezoelectric coefficient of the piezoelectric film material: d33 ═ Δ Q/Δ F.

according to the piezoelectric coefficient measuring device, when the area of the second electrode of the piezoelectric thin film material is smaller than that of the contact surface of the metal contact structure, the measuring device can measure the piezoelectric thin film material.

The invention will be further illustrated by the following specific examples