Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
1999-08-31
2001-08-14
Budd, Mark O. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
Reexamination Certificate
active
06274963
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to ultrasonic devices. More particularly, the present invention relates to methods and devices for controlling the vibration of ultrasonic transmission components by applying a plurality of signals to a transducer element through the use of a segmented electrode.
BACKGROUND OF THE INVENTION
Ultrasonic transmission devices are frequently used in a variety of applications, such as, for example, surgical operations and procedures. Ultrasonic surgical devices usually include a transducer assembly that converts electrical energy into vibrational motion at ultrasonic frequencies. The vibrational motion of the transducer assembly is transmitted to vibrate a distal end of a transmission component. The distal end of the transmission component, may transmit the ultrasonic energy to selected tissue of a patient, for example, to cut, dissect, and cauterize the tissue.
The ultrasonic vibration is induced in the transmission component by exciting one or more piezoelectric elements of the transducer assembly by an electrical signal. The electrical signal is transmitted to electrodes that are coupled to the piezoelectric elements. The electrodes are typically disposed on each side of the piezoelectric elements. When the electrical signal is transmitted to the electrodes, an electric field is established across the piezoelectric elements causing the piezoelectric elements to generate a mechanical standing wave at a frequency approximately equal to the frequency of the electrical excitation signal.
One of the problems associated with ultrasonic surgical instruments is uncontrolled and undampened vibrations of the transmission component as well as material fatigue resulting therefrom. Conventional mechanical dampening has been used to reduce undesired vibrations of transmission components of ultrasonic surgical instruments. For example, silicone rings have been disposed near nodes of the transmission component to reduce undesired vibration. However, the silicone rings can decrease the performance of the transmission component, dissipate desirable ultrasonic energy, increase the design time of the transmission component, and increase the heating of the transmission component. In addition, the distribution of current flow through the transducer assembly cannot be sensed or controlled.
Accordingly, there is a need for improved devices and methods to control the vibration of ultrasonic transmission components to allow the desired frequency to pass to the distal end of the transmission components. It would also be desirable to dampen the undesired vibration of the vibrational elements of the transducer assembly.
SUMMARY OF THE INVENTION
In view of the above, devices and methods are provided to control the vibration of ultrasonic transmission components. The devices and methods can undesired frequencies of vibration, such as, for example, non-fundamental modes, in vibrational elements of a transducer assembly and can control the electrical field distributed across the vibrational elements. The electrical properties (i.e., current, voltage, impedance, and phase) of the vibrational elements of the transducer assembly can be continuously monitored and adjusted to provide a desired vibrational frequency. The vibration of the transducer assembly can be controlled by applying a plurality of drive signals to a transducer element by the use of a segmented electrode.
The devices and methods can also introduce non-fundamental modes of vibration. The introduction of non-fundamental modes can allow more efficient delivery of power at the fundamental frequency of the transducer assembly. In addition, introduction of the non-fundamental modes of vibration can enhance tissue effects.
The devices and methods further allow longer and narrower transmission components (i.e., blades) to be utilized. Furthermore, mechanical dampening can be reduced, resulting in increased efficiency of the ultrasonic energy transmitted to the transmission component. The devices and methods also increase life expectancy of the transmission components.
An ultrasonic surgical device in accordance with the present invention includes a transducer assembly adapted to vibrate at an ultrasonic frequency in response to electrical energy. The transducer assembly includes at least one vibrational element and a segmented electrode. The segmented electrode has a plurality of input leads and plurality of contact regions. The plurality of contact regions are in electrical communication with the at least one vibrational element. A transmission component is adapted to receive the ultrasonic vibration from the transducer assembly and to transmit the ultrasonic vibration from a first end to a second end of the transmission component.
A transducer assembly in accordance with the present invention includes a transducer assembly comprising at least one transducer element having a first end and a second end. A first electrode is coupled to the first end and a segmented electrode is coupled to the second end. The segmented electrode is adapted to allow the transducer element to be simultaneously driven by a plurality of electric signals.
A generator in accordance with the present invention includes a frequency control loop to generate an electrical signal having a desired level of vibration. A first amplifier having a selected gain receives the electrical signal from the frequency control loop. The first amplifier generates a first output signal to drive the transducer element. A second amplifier having a selected gain receives the electrical signal from the frequency control loop. The second amplifier generates a second output signal to drive the transducer element.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The invention, together with attendant advantages, will best be understood by reference to the following detailed description of the preferred embodiments of the invention, taken in conjunction with the accompanying drawings.
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Alam Stephen J.
Estabrook Brian
Kellogg Scott
Budd Mark O.
Ethicon Endo-Surgery Inc.
Kreger, Jr. Verne E.
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