Tuning Fork Piezoelectric Oscillator Fine Trimming by Spot Trains
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Solution Overview
Problem
Existing piezoelectric oscillators face challenges in precise frequency adjustment due to limitations in laser trimming technology, particularly with small spot diameters, leading to increased production costs and reduced precision in frequency adjustment for miniaturized components.
Innovation Solution
A piezoelectric oscillator design featuring a weight portion with film removal spots arranged in spot trains at a pitch smaller than the spot diameter, allowing for fine trimming adjustments without the need for expensive laser trimming apparatuses, by forming film removal spots in a partially cut shape and adjusting train spaces to achieve target frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a smaller spot diameter laser is used for trimming, then frequency adjustment precision is improved, but device cost increases significantly
Solution Approach 1:
The patent divides the trimming process into multiple spot trains with different pitch values. The first spot train uses a larger pitch for coarse trimming, while the second spot train uses a smaller pitch for fine trimming. This segmentation allows achieving high precision without requiring a small spot diameter laser throughout the entire process, thus avoiding the need for expensive laser equipment.
Solution Approach 2:
The patent dynamically adjusts the pitch between spots in different trains. The pitch of the first spot train is set larger than that of the second spot train, allowing the process to transition from coarse to fine trimming. This dynamic pitch adjustment enables precision control without requiring a small spot diameter laser, resolving the contradiction between precision and cost.
2Measurement precision
If the pitch between laser spots is reduced to improve resolution, then frequency adjustment accuracy is improved, but the trimming length becomes insufficient for miniaturized oscillators
Solution Approach 1:
The patent segments the spot trains into multiple groups with different pitch values. The first spot train uses a larger pitch to cover a longer trimming length, while the second spot train uses a smaller pitch for high-resolution fine adjustment. This segmentation allows both long trimming length and high accuracy to be achieved in different stages.
Solution Approach 2:
The patent employs periodic action by conducting trimming in two sequential stages: first with a larger pitch for coarse adjustment, then with a smaller pitch for fine adjustment. This periodic approach with varying pitch values enables sufficient trimming length while maintaining high frequency adjustment accuracy.
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 approach enables high-resolution trimming and precise frequency adjustment close to the target frequency without using expensive laser trimming apparatuses, improving adjustment accuracy and reducing production costs.
Implementation Method 1
the mass adjustment film is partially removed as corresponding to a spot diameter by laser application
Implementation Method 2
a piezoelectric oscillator including: a weight portion having a mass adjustment film for frequency adjustment laminated on an oscillating arm of a tuning fork crystal vibrating piece
Data Source
AI summary
A piezoelectric oscillator which can conduct fine trimming adjustment and adjust frequencies highly precisely, particularly with no use of an expensive laser trimming apparatus with a small spot diameter, and a method of the same are provided. The method includes: a first step wherein a first spot train is formed on a mass adjustment film at a pitch smaller than the diameter of a film removal spot matched with the spot diameter of laser, and a second step wherein a train space to the first spot train is adjusted in accordance with the target frequency of a tuning fork crystal vibrating piece to form a second train and after, and these steps are in turn conducted, whereby fine trimming adjustment is performed.