Piezoelectric Vibrator Adjustment Films for Resonant Frequency Control
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Solution Overview
Problem
Existing piezoelectric vibrators manufactured using MEMS technology face inefficiencies in adjusting resonant frequencies due to variations in manufacturing, requiring inefficient adjustments such as beam irradiation or individual removal of mass parts.
Innovation Solution
A piezoelectric vibrator design featuring first and second adjustment films with different etching mass reduction rates, where the second adjustment film is exposed in regions of greater displacement, allowing for simultaneous etching to efficiently adjust resonant frequency while minimizing changes in spring constant and temperature characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single material additional film is formed on the electrode to adjust resonant frequency, then the resonant frequency can be adjusted, but it requires inefficient adjustment operations such as beam irradiation on each region to achieve different thicknesses
Solution Approach 1:
The additional film is divided into multiple regions with different thicknesses by forming it over a patterned mandrel structure. This segmentation allows different portions of the film to have predetermined thickness variations without requiring post-forming adjustment operations, thereby resolving the contradiction between achieving precise frequency adjustment and maintaining production efficiency
Solution Approach 2:
The mandrel structure is formed with a specific pattern before the additional film is deposited. This preliminary action establishes the thickness distribution of the additional film in advance, eliminating the need for subsequent beam irradiation or regional adjustment operations, thus improving productivity while maintaining manufacturing precision
2Manufacturing precision
If rough adjustment mass parts and fine adjustment mass parts are removed individually from vibrating arms, then resonant frequency can be adjusted, but it requires inefficient individual removal operations
Solution Approach 1:
Multiple adjustment functions (rough adjustment and fine adjustment) are merged into a single additional film structure. By forming this film with predetermined thickness variations over a patterned mandrel, both rough and fine adjustments are achieved simultaneously in one manufacturing step, eliminating the need for separate removal operations and thereby improving productivity while maintaining precision
3Manufacturing precision
If additional films are formed to adjust resonant frequency, then frequency can be tuned, but it may cause changes in frequency-temperature characteristics
Solution Approach 1:
The thickness of the additional film is varied across different regions by controlling the mandrel pattern geometry. This parameter change in film thickness allows precise adjustment of resonant frequency while the overall coverage and distribution are designed to minimize impact on frequency-temperature characteristics, thus resolving the contradiction between frequency tuning and temperature stability
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
Enables efficient adjustment of resonant frequency with reduced inefficiencies and minimal impact on frequency-temperature characteristics, simplifying the manufacturing process and improving frequency stability.
Implementation Method 1
a piezoelectric film, formed between the first electrode and the second electrode
Data Source
AI summary
A piezoelectric vibrator that includes a piezoelectric film with a pair of electrodes disposed on opposing sides of the piezoelectric film. Moreover, the vibrator includes first and second adjustment films with the first adjustment film covering the first surface of the piezoelectric film in a first region and the second adjustment film covering the first surface of the piezoelectric film in a second region that is different from the first region. Moreover, the second region of the piezoelectric film has a greater displacement than the first region when the piezoelectric vibrator vibrates.