KR102007526B1 - Method for Polarizing Piezoelectric Element - Google Patents

Abstract

Disclosed is a method for polarizing a piezoelectric element. According to an aspect of the present invention, the method for polarizing a piezoelectric element in an ultrasonic transducer comprises a step of applying DC power having a predetermined size to a piezoelectric element in a predetermined environment.

Description

Piezoelectric element polarization method {Method for Polarizing Piezoelectric Element}

The present invention relates to a method for polarizing a piezoelectric element.

The contents described in this section merely provide background information on the present embodiment and do not constitute a prior art.

Surgical scalpels have been conventionally used to cut or dissect organs or tissues, but there is a risk of bleeding caused by vascular damage and exposure to infection due to vascular damage by incorrect procedures. In addition, a separate suture process is required, thereby increasing the operation time.

To solve these problems, surgical devices using energy have been developed. Surgical devices using ultrasonic energy, radio frequency (RF), laser, plasma, etc. are known as the energy used.

Among them, the ultrasonic surgical apparatus using ultrasonic energy is a surgical equipment used in various surgical fields such as general surgery, orthopedics, ophthalmology, plastic surgery, urology or neurosurgery, and includes tissue incision, fragmentation, ablation and Perform functions such as sutures.

The ultrasound surgical device includes an end effector having a blade that vibrates at an ultrasonic frequency to cut and suture the tissue. The ultrasonic surgical device includes a piezoelectric element that converts power into ultrasonic vibrations, which are transmitted along the acoustic waveguide to the blade element. The action of the trigger causes the end effector to grasp or detach the tissue and to perform ablation and suture with the transmitted ultrasonic vibrations.

At this time, the piezoelectric element is changed in the property after the initial fabrication (for example, resonant frequency, impedance, etc.) and after being operated in a predetermined period of time mounted in the hand piece. The property change of the piezoelectric element is mainly due to the stress applied to the piezoelectric element from the outside of the piezoelectric element. The piezoelectric element is mounted in the hand piece by a fixing element such as a bolt, which fixes the piezoelectric element to a certain degree by applying a compressive force to the piezoelectric element. This is because there is a possibility that an excessive tensile force acts on the piezoelectric element during the operation of the piezoelectric element, and to prevent a physical (evil) effect on the piezoelectric element due to the excessive tensile force. However, since the fixed element applies a compressive force to the piezoelectric element as described above, the properties of the piezoelectric element are different from that at the time of initial manufacture.

The problem lies in the fact that the compressive forces exerted on the piezoelectric elements are different. The torque applied to the fixed element to fix the piezoelectric element in the handpiece manufacturing process may vary slightly every handpiece manufacturing process. This subtle change results in a problem that the final characteristics of the piezoelectric element mounted in the hand piece and operated for a predetermined period of time can be ensured because the piezoelectric element has a different property after all. This can cause difficulty in matching between the handpiece and the power supply. Accordingly, the operation of the entire ultrasonic surgical apparatus becomes unstable, the output efficiency is lowered, and the performance of the handpiece is deteriorated.

One embodiment of the present invention, by aging the piezoelectric element in a short time, it is an object to provide a fixed device fastening device for confirming the characteristics of the piezoelectric element in advance and preventing the aging of the piezoelectric element.

According to an aspect of the present invention, a method for polarizing a piezoelectric element in an ultrasonic transducer, the piezoelectric element polarization method comprising the step of applying a DC power of a predetermined size to the piezoelectric element in a predetermined environment. To provide.

According to an aspect of the invention, the predetermined environment is characterized in that the environment having a temperature below the Curie temperature of the piezoelectric element.

According to one aspect of the invention, the piezoelectric element is characterized in that the single crystal piezoelectric element.

According to an aspect of the present invention, the piezoelectric element is characterized in that the resonance frequency and the anti-resonant frequency is variable by the application process.

According to an aspect of the invention, the piezoelectric element is characterized in that the band of the resonance frequency and the anti-resonant frequency is narrowed.

According to an aspect of the present invention, in a vibrator in an ultrasonic transducer, a vibrator is provided comprising a piezoelectric element polarized by applying a DC power of a predetermined size in a predetermined environment.

According to an aspect of the invention, the predetermined environment is characterized in that the environment having a temperature below the Curie temperature of the piezoelectric element.

According to one aspect of the invention, the piezoelectric element is characterized in that the single crystal piezoelectric element.

According to an aspect of the present invention, the piezoelectric element is characterized in that the resonance frequency and the anti-resonant frequency is variable by the application process.

According to an aspect of the invention, the piezoelectric element is characterized in that the band of the resonance frequency and the anti-resonant frequency is narrowed.

As described above, according to an aspect of the present invention, by aging the piezoelectric element in a short time, there is an advantage that can confirm the characteristics of the piezoelectric element in advance and prevent the aging of the piezoelectric element.

1 is a view showing an ultrasound surgical apparatus according to an embodiment of the present invention.
2 is a view showing the configuration of a hand piece according to an embodiment of the present invention.
3 is a cross-sectional view of an oscillator according to an embodiment of the present invention.
4 is a diagram showing a state of the internal electric dipole when the piezoelectric element is first manufactured.
5 is a diagram showing a state of the internal electric dipole when the piezoelectric element is applied with power.
6 is a diagram illustrating a state of the internal electric dipole after the piezoelectric element is applied with power.
7 is a view of measuring the properties of the piezoelectric element when first manufactured.
8 is a diagram measuring the properties of the piezoelectric element after polarization.
9 is a flowchart illustrating a method of polarizing a piezoelectric element according to an embodiment of the present invention.
10 is a view showing a fastening device fastening system according to an embodiment of the present invention.
11 is a flowchart illustrating a method of fastening a fixed element according to an embodiment of the present invention.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

Terms such as first, second, A, and B may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. It is to be understood that the term "comprises" or "having" in the present application does not exclude in advance the possibility of the presence or addition of features, numbers, steps, operations, components, parts or combinations thereof described in the specification. .

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art.

Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

In addition, each component, process, process, or method included in each embodiment of the present invention may be shared within a range that is not technically contradictory.

1 is a view showing an ultrasound surgical apparatus according to an embodiment of the present invention.

1, the ultrasound surgical apparatus 100 according to an embodiment of the present invention is a power supply (Generator, 110), handpiece 120, hand instrument 130, shaft assembly 140, end effector ( 150 and handle assembly 160.

The power supply 110 supplies power to allow the handpiece 120 to vibrate.

The handpiece 120 receives power from the power supply 110 to generate vibration energy, and transmits ultrasonic vibration to the shaft assembly 140.

The handpiece 120 receives power from the power supply 110 to generate vibration energy. The handpiece 120 includes a piezoelectric element that converts electrical energy into vibration energy and vibration energy into electrical energy. The piezoelectric element receives power supplied from the power supply device 110 and converts the vibration energy into vibration energy.

Hand piece 120 transmits the generated ultrasonic vibration to shaft assembly 140. Hand piece 120 is coupled to hand instrument 130 and connected to shaft assembly 140. The hand piece 120 transmits vibration energy to the shaft assembly 140 so that the generated vibration energy can be delivered to the end effector 150.

The hand instrument 130 fixes the handpiece 120 and the shaft assembly 140 and controls the operation of each component in the ultrasound surgical apparatus 100.

Hand instrument 130 secures handpiece 120 and shaft assembly 140. The hand instrument 130 has an insertion opening for the handpiece 120 and the shaft assembly 140 to allow the handpiece 120 and the shaft assembly 140 to be inserted into the hand instrument 130. The hand instrument 130 fixes the inserted handpiece 120 and the shaft assembly 140, and transmits the vibration energy generated by the handpiece 120 to the shaft assembly 140 so that the vibration energy is transmitted to the shaft assembly 140. Through) to be delivered to the end effector 150.

The hand instrument 130 includes a controller (not shown) therein to control the operation of each component in the ultrasound surgical apparatus 100. The hand instrument 130 includes an input unit (not shown) for receiving an input such as an operation method of the end effector 150 from the user, and the controller (not shown) controls the operation of each component according to the user's input. For example, when the user's input is an input for cutting tissue using an end effector, the controller (not shown) increases the power of the power supply 110 to determine the amount of vibration energy generated by the hand piece 120. Can be increased.

The shaft assembly 140 delivers the vibration energy transmitted from the hand instrument 130 to the end effector 150. One end of the shaft assembly 140 is connected to the end effector 150, the other end is inserted into the insertion hole of the hand instrument 130 is fixed. The shaft assembly 140 is fixed to the hand instrument 130, receives the vibration energy transmitted from the hand instrument 130, and transmits the applied vibration energy to the end effector 150. In addition, the shaft assembly 140 may rotate within the insertion hole of the hand instrument 130, thereby controlling the direction of the end effector.

The end effector 150 grips the tissue and cuts and sutures the tissue using the received vibration energy. The end effector 150 grips or moves away from the tissue, depending on the operation of the handle assembly 160. When gripping tissue, the end effector 150 cuts and seals the tissue using the transmitted vibration energy.

The handle assembly 160 allows the user to grip the ultrasound surgical apparatus 100 and to control the operation of the end effector 150. The handle assembly 160 includes a handle part for allowing a user to grip the ultrasound surgical apparatus 100 and a trigger part for controlling a gripping operation of the end effector 150.

2 is a view showing the configuration of a hand piece according to an embodiment of the present invention, Figure 3 is a view showing a cross section of the vibrator according to an embodiment of the present invention.

2 and 3, the hand piece 120 according to an embodiment of the present invention includes a housing 210 and a vibrator 220.

The vibrator 220 is disposed inside the housing 210 and vibrates by receiving power applied from a power supply device.

The vibrator 220 includes a fixed element 222, a tail mass 224, a piezoelectric element 226, and a head horn 228.

The fixed element 222 is coupled to the head horn 228 via the piezoelectric element 226 to fix the piezoelectric element 226, so that the vibration energy of the piezoelectric element 226 can be completely transmitted to the head horn 228. do.

Since the fixed element 222 is coupled to the head horn 228 via the piezoelectric element 226, as shown in FIG. 2, the piezoelectric element 226 is disposed between the fixed element 222 and the head horn 228. Is fixed at. As the torque is applied to the fixed element 222 from the outside, the fixed element 222 and the head horn 228 may be coupled to each other.

At this time, by the torque acting on the fixed element 222, the fixed element 222 exerts a force in the direction of the piezoelectric element 226, the head horn 228 also in response to the force acting on the fixed element 222 A force of the same magnitude is applied in the direction of the piezoelectric element 226. The piezoelectric element 226 is fixed by the fixed element 222 but at the same time is stressed by the fixed element 222 and the head horn 228. The stress acting on the piezoelectric element 226 causes the piezoelectric element to change until the polarization is completed and the change of the piezoelectric element no longer occurs. The properties of the piezoelectric element include the resonant frequency, anti-resonant frequency or impedance of the piezoelectric element. The property change of the piezoelectric element is not a problem if the piezoelectric element is polycrystalline. Since the polarization of the polycrystalline piezoelectric element is completed within a short time (for example, several hours), it is possible to flexibly cope with the property change of the piezoelectric element. However, since the polarization of a single crystal piezoelectric element is typically consumed from several days to as many as several tens of days, the piezoelectric element is continuously mounted while operating in the handpiece, and thus the properties of the single crystal piezoelectric element are changed. It is causing difficulty in matching.

The piezoelectric element 226 receives power from a power supply device and generates vibration energy.

The piezoelectric element 226 is formed of a single crystalline material. Piezoelectric elements of a single crystalline material has an advantage that the piezoelectric constant is several times higher than piezoelectric elements of a polycrystalline material. Accordingly, even when the same electric power is applied to the piezoelectric element, the vibration displacement of the piezoelectric element of the single crystalline material is increased, and thus it can have better performance. However, as described above, unlike the polycrystalline piezoelectric element, the single crystal piezoelectric element consumes considerable time until the polarization is completed and the property change no longer occurs due to external factors. According to this characteristic, the first (monocrystalline) piezoelectric element produced is stressed and its property changes continuously. The process by which the property change occurs and the result of the property change are shown in FIGS. 4 to 8.

4 is a diagram showing a state of an internal electric dipole when a piezoelectric element is first manufactured, and FIG. 5 is a diagram showing a state of an internal electric dipole when a piezoelectric element is applied with power, and FIG. 6 is a piezoelectric element. Is a diagram showing the state of the internal electric dipole after power is applied.

Fig. 4 (a) is a cross section of the (monocrystalline) piezoelectric element originally produced, and Fig. 4 (b) shows the state of the dipole on its Weiss Domain. Inside the first piezoelectric element, the dipoles are arranged in disorder without any specific orientation.

At this time, when a DC power source is applied to the piezoelectric element, each dipole is aligned with the direction of the power source, as shown in FIG. 5.

Even if the application of the DC power supply to the piezoelectric element is stopped, the dipoles in the piezoelectric element generally maintain the aligned direction unless there is a separate external stress. However, when external stress is applied to the piezoelectric element, the alignment direction of the dipoles in the piezoelectric element is variable. If the alignment direction of the dipoles is changed by 180 °, the change of the properties of the piezoelectric element is minimal, but if the alignment direction of the dipoles is changed by 90 °, the properties of the piezoelectric element are changed considerably. For example, the resonant frequency of the piezoelectric element is increased, the anti-resonant frequency is decreased, or the impedance is variable.

As described above, the piezoelectric element is fixed by the fixed element, and stress is applied to the piezoelectric element in the fixing process. For this reason, the property change of a piezoelectric element will generate | occur | produce continuously until all polarization is completed. This can be seen in FIGS. 7 and 8.

FIG. 7 is a diagram measuring the properties of the piezoelectric element when first manufactured, and FIG. 8 is a diagram measuring the properties of the piezoelectric element after polarization.

In FIG. 7, the resonance frequency 710 and the anti-resonance frequency 715 of the first piezoelectric element are illustrated, and the measured impedance 720 is illustrated. Impedance 720 is measured about 4Ω.

On the other hand, the resonant frequency 810 of the piezoelectric element in which the polarization is completed after several days or tens of days has become relatively large, and the anti-resonant frequency 815 has become relatively small. As a result, the resonant frequency and the anti-resonant frequency band were changed to narrow bands. In addition, the impedance 820 is about 5.7Ω measured to confirm that the impedance is variable.

Referring again to FIGS. 2 and 3, as described above, as the polarization proceeds for a long time and the properties of the piezoelectric element change, the piezoelectric element 226 is solved to solve the problem of misalignment with other components (particularly, the power supply). In the preset environment, polarization proceeds rapidly by applying DC voltage of predetermined size. The preset environment may be set such that the temperature around the piezoelectric element 226 or the piezoelectric element 226 is a temperature below the Curie temperature T _C. This is because the polarization efficiency of the piezoelectric element 226 increases as the temperature around the piezoelectric element 226 or the piezoelectric element 226 rises (within the Curie temperature). The piezoelectric element 226 or the piezoelectric element 226 is heated to a temperature below the Curie temperature T _C , and a DC voltage having a predetermined magnitude is applied to the piezoelectric element 226. At this time, the magnitude of the DC voltage applied to the piezoelectric element 226 is significantly lower than that of the polycrystalline piezoelectric element. The piezoelectric element 226 formed of a single crystal material needs only 1KV to 2KV, but the polycrystalline piezoelectric element needs to be applied to 3KV to 4KC, so the voltage required for polarization is about 2 to 3 times different. As such, when a DC voltage having a predetermined magnitude is applied to the piezoelectric element 226 in a predetermined environment, polarization of the piezoelectric element 226 is performed within several tens of minutes to several hours. That is, the time until the polarization of the piezoelectric element 226 is completed has an advantage of shortening from about several tens to several hundred times. Accordingly, the piezoelectric element according to an embodiment of the present invention is different from the conventional piezoelectric element, which is disposed in the handpiece and changes its properties little by little every time it is operated for several days to several tens, thereby having to perform impedance matching and frequency matching every operation. 226 has the advantage that additional polarization, such as impedance matching and frequency matching, is unnecessary because polarization is completed within a short time.

The head horn 228 vibrates together with the vibration of the piezoelectric element 226, and transmits vibration energy to the outside of the handpiece 120.

9 is a flowchart illustrating a method of polarizing a piezoelectric element according to an embodiment of the present invention.

The DC electrode is connected to the piezoelectric element 226 (S910). In order to induce polarization by applying a DC power having a predetermined size to the piezoelectric element 226, a DC electrode is connected to the piezoelectric element 226.

In operation S920, a DC power having a predetermined size is applied to the piezoelectric element 226 in a preset environment. After the piezoelectric element 226 or the piezoelectric element 226 is heated by a temperature lower than the Curie temperature, a DC power having a predetermined size is applied to the piezoelectric element 226. Accordingly, even if the piezoelectric element 226 is made of a single crystal material, polarization is performed within several tens of minutes to several hours.

In FIG. 9, each process is described as being sequentially executed, but this is merely illustrative of the technical idea of the exemplary embodiment of the present invention. In other words, a person of ordinary skill in the art to which an embodiment of the present invention belongs may execute the process described in FIG. 9 by changing the order of one or more of each process without departing from the essential characteristics of the embodiment of the present invention. 9 may not be limited to time-series order because it may be variously modified and modified to be executed in parallel.

9 may be embodied as computer readable codes on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. That is, computer-readable recording media include storage media such as magnetic storage media (eg, ROMs, floppy disks, hard disks, etc.) and optical reading media (eg, CD-ROMs, DVDs, etc.). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The above description is merely illustrative of the technical idea of the present embodiment, and those skilled in the art to which the present embodiment belongs may make various modifications and changes without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of the present embodiment but to describe the present invention, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present embodiment.

100: ultrasonic surgical device
110: power supply
120: handpiece
130: hand instrument
140: shaft assembly
150: end effector
160: handle assembly
210: housing
220: oscillator
222: fixed element
224: tail mass
226: piezoelectric element
228 head horn

Claims (10)

delete delete delete delete delete In the vibrator in the ultrasonic transducer comprising a fixed element, a piezoelectric element and a head horn,
Tail mass;
A fixed element coupled to the head horn via the piezoelectric element to fix the piezoelectric element, such that vibration energy of the piezoelectric body can be transmitted to the head horn;
A piezoelectric element that is polarized by being applied in a preset environment with a predetermined size of DC power and generates vibration energy by receiving power from the outside; And
Vibrating together in accordance with the vibration of the piezoelectric element, including a head horn for transmitting the vibration energy to the outside,
The piezoelectric element is fixed between the fixed element and the head horn,
The fixed element exerts a force in the direction of the piezoelectric element by a torque applied from the outside, and by applying a force of the same magnitude in the direction of the head mixed piezoelectric element in response to the force acting on the fixed element, the piezoelectric element is fixed Stressed by the device and the head horn, causing a property change until the polarization is completed,
The property of the piezoelectric element includes the resonant frequency, anti-resonant frequency or impedance of the piezoelectric element,
When the polarization is completed, the resonant frequency of the piezoelectric element increases and the anti-resonant frequency of the piezoelectric element decreases so that the resonant frequency and anti-resonant frequency band of the piezoelectric element change into narrow bands, and the impedance of the piezoelectric element increases,
The piezoelectric element is formed of a single crystalline material, and when the DC power of the predetermined size is applied, the dipoles in the piezoelectric element are aligned in the direction of the power, and when external stress is applied to the piezoelectric element, the piezoelectric element is The direction of dipoles is variable and the properties of the piezoelectric element are variable,
Polarization of the piezoelectric element is a voltage lower than the DC voltage to be applied for polarization of the polycrystalline piezoelectric element in the environment where the temperature of the piezoelectric element has a temperature below the Curie temperature is applied to the piezoelectric element, An oscillator, characterized in that the polarization of the piezoelectric element is made within a predetermined time.
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