Piezoelectric Vibrator Trimming Layout for Stable Resonant Frequency
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Solution Overview
Problem
Existing piezoelectric vibrator elements face frequency fluctuations due to burr formation and separation of electrode films during laser trimming, leading to instability in resonant frequency adjustments.
Innovation Solution
The design includes a reverse side exposure part on the vibrating arm part to prevent laser irradiation of the electrode film, using a picosecond or femtosecond laser to trim the weight metal film and electrode film together, ensuring the electrode film is not irradiated and thus preventing burr formation and frequency fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser beam is used to trim the weight metal film, then frequency adjustment is achieved, but the electrode film on the reverse surface is irradiated causing burr formation and frequency fluctuation
Solution Approach 1:
The patent divides the laser trimming process into two distinct stages: coarse trimming of the weight metal film and fine trimming of the electrode film. This segmentation allows each stage to be optimized independently - the first stage removes the bulk material while the second stage precisely shapes the electrode film edge without causing burrs, thereby resolving the contradiction between adjustment precision and frequency stability
Solution Approach 2:
The patent applies preliminary action by performing coarse trimming of the weight metal film before fine trimming of the electrode film. By removing the bulk material first, the subsequent fine trimming operates on a smaller, more controlled area, enabling precise frequency adjustment without irradiating and damaging the electrode film, thus maintaining frequency stability
2Manufacturing precision
If ion beam is used for fine adjustment of the weight metal film, then frequency precision is improved, but the process complexity increases
Solution Approach 1:
The patent extracts the fine trimming function from the weight metal film processing and applies it separately to the electrode film. Instead of using complex ion beam equipment for the entire process, the invention uses a simplified two-stage laser process where the first stage handles weight metal removal and the second stage handles precise electrode film shaping, thereby reducing device complexity while maintaining precision
Solution Approach 2:
The patent changes the laser parameters between the two trimming stages. The first stage uses laser parameters optimized for removing weight metal film, while the second stage uses different parameters optimized for precise electrode film trimming. This parameter adjustment allows a single laser device to perform both functions, avoiding the need for complex ion beam equipment
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 enhances vibration characteristics and quality by stabilizing the resonant frequency, preventing frequency fluctuations, and ensuring reliable operation of the piezoelectric vibrator element.
Implementation Method 1
by a voltage being applied to the excitation electrodes, the vibrating arm parts vibrate with a predetermined resonant frequency
Implementation Method 2
the weight metal film is irradiated with a laser beam to partially eliminate the weight metal film
Data Source
AI summary
There is provided a piezoelectric vibrator element which is excellent in vibration characteristics, high in quality, and capable of suppressing a frequency fluctuation after a frequency adjustment. The piezoelectric vibrator element is provided with a piezoelectric plate having a pair of vibrating arm parts, an electrode film disposed on obverse and reverse surfaces of the piezoelectric plate, and weight metal films for a frequency adjustment disposed on the electrode film at the obverse surface side in the vibrating arm parts. The reverse surface of the vibrating arm part has a reverse side exposure part from which the piezoelectric plate is exposed. The obverse surface of the vibrating arm part has an obverse side exposure part from which the weight metal film and the electrode film are removed, and from which the piezoelectric plate is exposed. A whole of the obverse side exposure part overlaps the reverse side exposure part at a distance from the electrode film on the reverse surface viewed from a thickness direction of the piezoelectric plate.