TWI530692B - Electrical property measurement method for thin film piezoelectric material - Google Patents

Description

Electrical measurement method of thin film piezoelectric material

The present invention relates to an electrical measurement method, and more particularly to a method for measuring the electrical properties of a thin film type piezoelectric material.

Piezoelectric material refers to a crystalline material that exhibits a voltage between two end faces when subjected to pressure. The piezoelectric material is widely used in sensor components due to its advantages of large output, small displacement, fast response, fast energy conversion, low price, and no electromagnetic interference, such as seismic sensors, force, velocity and acceleration. Measuring elements and electroacoustic sensors are used in many applications. The piezoelectric material has a piezoelectric effect due to the special arrangement of atoms in the crystal lattice, which causes the material to have a coupling effect between the stress field and the electric field.

The so-called piezoelectric effect (Piezoelectricity) is a phenomenon in which a mechanical energy exchanges with electrical energy. When physical pressure is applied to the piezoelectric material, the electricity in the body of the material The dipole moment is shortened by compression. At this time, the piezoelectric material resists this change and generates an equal amount of positive and negative charges on the opposite surface of the material to maintain the original state. This phenomenon of polarization due to deformation is called "positive piezoelectric effect". The positive piezoelectric effect is essentially a process in which mechanical energy is converted into electrical energy.

According to the specific material form, it can be divided into two types: piezoelectric block material and piezoelectric film. Due to the size of the film, the piezoelectric effect is difficult to measure due to the size, and the manufacturer cannot perform the performance evaluation at the material manufacturing stage when producing related products for piezoelectric applications.

Please refer to China M415305 simple piezoelectric material characteristic measurement system, 201243350 piezoelectric material characteristic measurement system, 201326773 pressure sensor electrical measurement device and 201217795 thin film electrical measurement device, which are all aimed at measuring pressure Development of electrical material properties. among them: The M415305 simple piezoelectric material characteristic measurement system is mainly composed of data capture card, power amplifier, speaker, charge amplifier and computer (including processing program). After the data is captured by the computer, the voltage signal is sent to the power amplifier to push the speaker. The pressure generated by the speaker is applied to the piezoelectric material. The pressure is also measured by the pressure gauge and the pressure value is transmitted to the computer. After the piezoelectric material is pressed, the charge is released, amplified by the charge amplifier, and transmitted to the input port of the data capture card, and the computer extracts the charge signal for processing and display processing results.

The 201243350 piezoelectric material characteristic measuring system comprises a platform and a first fixing frame, a second fixing frame and a third fixing frame disposed thereon; The first fixing frame has a sound emitting surface; a power transmission mechanism has a force receiving end and a force applying end, and when the force receiving end receives a test pressure, the test pressure is transmitted to the force applying a pressure sensor connected to the power transmission mechanism to sense the test pressure to generate a pressure signal; a data extractor electrically connecting the speaker and the pressure sensor; and a computer The data extractor is connected to the data extractor and controlled.

The electrical measuring device of the 201326773 pressure sensor includes a first plate body; a second plate body that is opened or closed relative to the second plate body; and a to-be-measured object is disposed in the first Between a plate and the second plate; an electrical measuring unit for measuring the electrical signal of the object to be measured; and a fluid supply system for connecting the first plate or the second plate with the receiving body Forming a space between the pressing faces, the fluid supply system provides a fluid to the space to press the fluid to the object to be measured, and the electrical measuring unit measures the electrical property of the object to be measured Signal. The case further discloses an electrical measurement correction method for a pressure sensor.

In addition, the 201217795 thin film electrical measuring device comprises a measuring unit and a reading unit. The measuring unit comprises two phase-spaced and cylindrical contact members, each of the contact members having an electrically conductive and flat circumferential surface, continuously contacting and electrically connecting a film to be tested to the two A section on the circumferential surface of the contact member and the film to be tested between the two contacts is defined as a section to be tested. The reading unit is electrically connected to the two contacts of the measuring unit to measure electrical characteristics of the section to be tested of the film to be tested. Since the film to be tested is continuously rolled, that is, the test is to be tested. The film sheet is continuously rubbed against the circumferential surface of the contact member, and the flat surface of the contact member can effectively prevent the film to be tested from being scratched.

The main object of the present invention is to provide a method for measuring the electrical properties of a thin film piezoelectric material, in particular, a method for measuring a piezoelectric effect constant of a thin film piezoelectric material, which can be used by a manufacturer for piezoelectric applications. When the product is related, its performance evaluation is carried out at the material processing stage.

The above main object of the present invention is achieved by the following specific technical means: An electrical measurement method for a film-type piezoelectric material converts an input signal into a vibration potential energy, which can be applied to a film-type piezoelectric material to be tested, and the film-type piezoelectric material to be tested is subjected to a positive voltage The effect produces a voltage change, and finally the data of the voltage change is compared with the data of the voltage change of a standard thin film type piezoelectric material test piece to interpret and know the electrical data of the film type piezoelectric material to be tested.

The electrical measurement method of the thin film type piezoelectric material as described above, wherein the input signal is a pulse wave signal.

The electrical measurement method of the thin film type piezoelectric material as described above, wherein the input signal is converted into the vibration potential energy through a transducer.

The electrical measurement method of the thin film type piezoelectric material as described above, wherein the data of the voltage change and the voltage change of a standard thin film type piezoelectric material test piece Comparing with each other, in the step of interpreting and learning the electrical data of the film-type piezoelectric material to be tested, firstly, the voltage change of the film-type piezoelectric material to be tested due to the positive voltage effect is first passed through a switching circuit. The data of the voltage change, the data of the first voltage change is transmitted to an electrical information judging unit, and the voltage change of the film-type piezoelectric material to be tested due to the positive voltage effect is obtained through a capacitor loop to obtain the data of the second voltage change. The data of the second voltage change is also transmitted to the electrical information judging unit, and the data of the first and second voltage changes are substituted into the operational test piece and compared with the standard film type piezoelectric material test piece to obtain the film to be tested. Electrical data of piezoelectric materials; the formula: for quartz

With C, V ₁ ^c = t ₁ × V ₁

Without C, V ₂ ^c = t ₂ × V ₂

For film

With C, V ₁ '= × V ₁ '

Without C, V ₂ '= × V ₂ '

Wherein, V ₁ ^c and V ₂ ^c are known piezoelectric material electrical data, and V ₁ ', V ₂ ' are electrical data of the piezoelectric material to be tested, t ₁ , t ₂ , , Then it corresponds to the time measured by different responses, but since the source pulses are the same, these four times will be equal. Is the piezoelectric coefficient after the effect of the capacitor is removed, It is a piezoelectric coefficient of a known ruthenium oxide thin film type piezoelectric material.

The invention has the advantages that the invention realizes the piezoelectric coefficient of the piezoelectric material of the film to be tested by converting the externally input signal into the vibration potential energy and judging by the electrical information fed back by the piezoelectric material of the film to be tested. The evaluation can provide the parameters of the manufacturer's various piezoelectric application products for parameter setting, and provide instant film characteristics judgment during the process; and the method of the invention has the characteristics of low cost, easy construction, mass production, and the like, and is progressive. .

(1) ‧ ‧ pedestal

(2) ‧‧‧cantilever

(11) ‧‧‧ Displacement output

(21) ‧ ‧ first end

(22) ‧‧‧ second end

(3) ‧‧‧Transducer

(A) ‧ ‧ film type piezoelectric material to be tested

(4) ‧‧‧ pulse generator

(5) ‧‧‧Electric information judgment unit

(51)‧‧‧Switching circuit

(52) ‧‧‧Capacitor circuit

First: Schematic diagram of the measurement process of the present invention

Second: Schematic diagram of the architecture of the measuring device used in the measuring method of the present invention

For a more complete and clear disclosure of the technical content, the purpose of the invention and the effects thereof achieved by the present invention, the following is a detailed description, and please refer to the illustrated drawings and drawings: please refer to the first The figure and the second figure are respectively a schematic diagram of the measurement flow diagram of the present invention and the architecture of the measurement apparatus used in the measurement method of the present invention.

The electrical measurement method of the thin film piezoelectric material of the present invention comprises the following steps: (1) converting an input signal into a vibration potential; wherein the input signal is preferably a pulse signal, and the input signal is converted into the vibration potential through a transducer; (2) the vibration bit is It can act on the film-type piezoelectric material to be tested, and the voltage change occurs due to the positive voltage effect; (3) the data of the voltage change generated by the film-type piezoelectric material to be tested and a standard film type piezoelectric material test piece The voltage change data are compared with each other to determine and know the electrical data of the film-type piezoelectric material to be tested; wherein, the voltage change of the film-type piezoelectric material to be tested due to the positive voltage effect is passed through a switching circuit. Obtaining data of the first voltage change, the data of the first voltage change is transmitted to an electrical information judging unit, and then the voltage change caused by the positive voltage effect of the film-type piezoelectric material to be tested is obtained through a capacitor loop to obtain a second voltage. The data of the change, the data of the second voltage change is also transmitted to the electrical information judging unit, and the data of the first and second voltage changes are substituted into the calculation formula and compared with the standard film type piezoelectric material test piece. The interpretation to obtain electrical test data of the film-shaped piezoelectric material; the expression: for quartz

With C, V ₁ ^c = t ₁ × V ₁

Without C, V ₂ ^c = t ₂ × V ₂

For film

With C, V ₁ '= × V ₁ '

Without C, V ₂ '= × V ₂ '

Where V ₁ ^c and V ₂ ^c are the voltages of known piezoelectric materials, V ₁ ', V ₂ ' are the voltages of the piezoelectric material to be tested, t ₁ , t ₂ , , Then it corresponds to the time measured by different responses, but since the source pulses are the same, these four times will be equal. Is the piezoelectric coefficient after the effect of the capacitor is removed, The piezoelectric coefficient of the known ruthenium oxide thin film type piezoelectric material has a piezoelectric coefficient of 2.3 × 10 ^-12 .

Assume that V ₁ = 50 mV , V ₂ = 20 mV , t = 4k Hz are known

Then V ₁ ^c = t ₁ × V ₁ = 4 × 50 = 200

V ₂ ^c = t ₂ × V ₂ = 4 × 20 = 80

Measuring the voltage of the film-type piezoelectric material to be tested V ₁ '=100 mV , V ₂ '=50 mV

Then V ₁ '= × V ₁ '=4×100=400

V ₂ ^' = × V ₂ '=4×50=200

=3×(2.3×10 ^-12 ) =6.9×10 ^-12

The measuring method of the present invention is mainly performed by an electrical measuring device of a thin film type piezoelectric material, the device comprising: a base (1) for mounting the cantilever (2); Preferably, the base (1) adopts a lifting platform, and has a displacement output end (11), the cantilever (2) is mounted on the displacement output end (11); and the displacement output end ( 11) is an insulating cylinder; a cantilever (2) having a first end (21) and a second end (22) opposite the first end (21), the cantilever (2) One end (21) is engaged with the displacement output end (11); wherein, preferably, the cantilever (2) is made of stainless steel and has appropriate rigidity according to the film type piezoelectric material to be tested (A) The pressure of the pressure is acceptable; a transducer (3), which is disposed at the second end of the cantilever (2), converts the externally input signal data into vibration energy, and the transducer (3) a film-type piezoelectric material (A) to be tested is placed under the corresponding one; a pulse generator (4) is used to generate a pulse wave and output the pulse wave generated thereby to the transducer; Electrical information judgment (5), the piezoelectric film (A) to be tested is electrically connected to the electrical information judging unit (5), and the electrical information outputted by the film-type piezoelectric material (A) to be tested is sent to the The electrical information judging unit (5) performs the interpretation of the piezoelectric coefficient of the film-type piezoelectric material (A) to be tested; wherein the electrical information judging unit (5) further comprises a switching circuit (51) and a capacitor circuit ( 52), the switch back The circuit (51) and the capacitor circuit (52) are connected in parallel with each other, and are electrically connected to the film-type piezoelectric material (A) to be tested, so as to measure the first film-type piezoelectric material (A) to be tested. The data of the voltage change and the data of the second voltage change are fed back to the electrical information judging unit (5) via the switching circuit (51) and the capacitor circuit (52), respectively.

That is, when a film-type piezoelectric material (A) to be tested is to be measured, the film-type piezoelectric material (A) to be tested is placed under the transducer (3) and is offset therefrom, and then Triggering the pulse generator (4) to cause the pulse generator (4) to send a pulse wave to the transducer (3), and the transducer (3) outputs the pulse generator (4) The pulse wave signal is converted into a vibration potential energy, and the vibration bit can be stably transmitted to the film type piezoelectric material (A) to be tested, and the film type piezoelectric material (A) generates a voltage change due to the positive piezoelectric effect, and the piezoelectric change The electrical information judging unit (5) is further fed back to the electrical information judging unit (5) for determining the electrical information of the film-type piezoelectric material (A) to be tested.

The above is only a part of the embodiments of the present invention, and is not intended to limit the present invention. It is intended to be included in the scope of the present invention.

In summary, the embodiments of the present invention can achieve the expected use efficiency, and the specific technical means disclosed therein have not been seen in similar products, nor have they been disclosed before the application, and have completely complied with the patent law. The regulations and requirements, the application for invention patents in accordance with the law, and the application for review, and the grant of patents, are truly sensible.

Claims (3)

An electrical measurement method for a film-type piezoelectric material converts an input signal into a vibration potential energy, which can be applied to a film-type piezoelectric material to be tested, and the film-type piezoelectric material to be tested is subjected to a positive voltage The effect produces a voltage change, and finally the data of the voltage change is compared with the data of the voltage change of a standard film type piezoelectric material test piece to interpret and know the electrical data of the film type piezoelectric material to be tested; Comparing the data of the voltage change with the data of the voltage change of a standard film type piezoelectric material test piece, in order to interpret and know the electrical data of the film type piezoelectric material to be tested, the first test is to be tested The film type piezoelectric material obtains the data of the first voltage change through a switching circuit by the voltage change caused by the positive voltage effect, and the data of the first voltage change is transmitted to an electrical information judging unit, and then the film to be tested is pressed. The voltage change of the electrical material due to the positive voltage effect obtains data of the second voltage change through a capacitor loop, and the data of the second voltage change is also transmitted to the electrical information judging unit The expression comparing the first and second voltage variation of the data and generation of standard thin-film piezoelectric material of the test piece, to obtain electrically interpretation of the test data of the film-shaped piezoelectric material; the expression: for quartz with C, V ₁ ^c = t ₁ × V ₁ without C, V ₂ ^c = t ₂ × V ₂ for film with C, V ₁ '= × V ₁ ' without C, V ₂ '= × V ₂ ' Wherein, V ₁ ^c and V ₂ ^c are known piezoelectric material electrical data, and V ₁ ', V ₂ ' are electrical data of the piezoelectric material to be tested, t ₁ , t ₂ , , Then it corresponds to the time measured by different responses, but since the source pulses are the same, these four times will be equal. Is the piezoelectric coefficient after the effect of the capacitor is removed, It is a piezoelectric coefficient of a known ruthenium oxide thin film type piezoelectric material. The method for measuring the electrical properties of a thin film piezoelectric material according to claim 1, wherein the input signal is converted into the vibration potential energy through a transducer. The method for electrical measurement of a thin film type piezoelectric material according to claim 1 or 2, wherein the input signal is a pulse wave signal.