Piezoelectric Vibration Element Asymmetric Electrode Offset
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Solution Overview
Problem
Piezoelectric vibration devices with bimorph type plate-shaped elements experience rapid amplitude changes at specific frequencies, leading to distortion in transmitted sound information.
Innovation Solution
A piezoelectric vibration element with alternately disposed electrodes and piezoelectric layers performs bending vibration, where the center of the facing portion in one direction is positioned differently from the center of the element, reducing rapid amplitude changes by distributing standing waves effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bimorph type plate-shaped piezoelectric element is used to vibrate the diaphragm, then the piezoelectric vibration device can be constructed with simple structure, but rapid amplitude change occurs at specific frequency causing distortion in transmitted sound information
Solution Approach 1:
The patent applies asymmetry by positioning the facing portion (where adjacent electrodes with different potentials face each other) at an asymmetric location relative to the piezoelectric element's center. Specifically, the facing portion is positioned such that its center in the second direction (width direction) does not coincide with the center of the piezoelectric element in the same direction. This asymmetric configuration modifies the standing wave distribution, reducing rapid amplitude changes at specific frequencies and thereby improving sound information transmission quality without complicating the device structure.
2Ease of manufacture
If the center of the facing portion coincides with the center of the piezoelectric element, then the structure is symmetric and simple to manufacture, but rapid amplitude change at specific frequency occurs
Solution Approach 1:
The patent deliberately introduces asymmetry in the positioning of the facing portion relative to the piezoelectric element center. The facing portion, which is critical for generating the bending vibration, is positioned such that its center in the width direction (second direction) is offset from the center of the piezoelectric element. This asymmetric arrangement effectively suppresses rapid amplitude changes at specific frequencies caused by standing waves, while still maintaining manufacturing feasibility through precise positioning during assembly.
3Speed
If standing waves are concentrated at specific frequency, then vibration amplitude is enhanced at that frequency, but distortion occurs in transmitted sound information
Solution Approach 1:
The asymmetric positioning of the facing portion relative to the piezoelectric element center modifies the standing wave pattern generated during vibration. By offsetting the facing portion's center in the width direction from the element's center, the standing wave energy is redistributed across a broader frequency range rather than being concentrated at a single specific frequency. This reduces the harmful effects of rapid amplitude changes while preserving sufficient vibration amplitude for effective sound transmission.
Solution Approach 2:
The patent utilizes the dynamic vibration characteristics of the piezoelectric element by controlling the bending vibration mode through asymmetric electrode positioning. The offset configuration of the facing portion creates a more uniform dynamic response across the operating frequency range, preventing excessive amplitude concentration at resonant frequencies and thereby reducing distortion in the transmitted sound information.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration results in a piezoelectric vibration device with reduced rapid amplitude changes at specific frequencies, minimizing distortion in sound information transmission.
Implementation Method 1
a piezoelectric vibration element includes at least a plurality of electrodes and a plurality of piezoelectric layers alternately disposed in a first direction, and performs bending vibration in the first direction so as to change amplitude in a second direction vertical to the first direction by inputting of an electric signal
Data Source
AI summary
A piezoelectric vibration element which includes at least a plurality of electrodes and a plurality of piezoelectric layers alternately disposed in a first direction, and performs bending vibration in the first direction so as to change amplitude in a second direction vertical to the first direction by inputting an electric signal, and in which a center of a facing portion in the second direction is provided at a different position from a center of the piezoelectric vibration element in the second direction, the facing portion including a portion in which one of the piezoelectric layers interposed between the electrodes that are disposed so as to be adjacently opposed to each other, and a piezoelectric vibration device and a portable terminal using the piezoelectric vibration element are provided.