Tuning Fork Crystal Plate Layout for Stable Frequency and Impedance
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Solution Overview
Problem
Conventional tuning fork crystal oscillation plates experience variations in frequency due to inaccuracies in groove formation, leading to unstable crystal impedance and increased manufacturing costs, primarily due to the limitations of double-sided projection exposure apparatuses and complex multi-step processes.
Innovation Solution
A tuning fork crystal oscillation plate design with grooves formed on one main surface of the oscillation arms, extending from the base to the distal ends, and a manufacturing method that reduces the number of exposure steps and alignment errors, using a single-sided etching process to form the grooves and electrodes, thereby stabilizing the frequency and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If grooves are formed on both front and rear main surfaces of oscillation arms using double-sided projection exposure, then electrode connections are achieved, but manufacturing precision deteriorates due to alignment errors between front and rear surfaces
Solution Approach 1:
The invention extracts the groove formation process from the double-sided exposure process. Instead of forming grooves on both front and rear surfaces through complex alignment, the invention forms grooves only on the front main surface through a single exposure process, eliminating alignment errors between front and rear surfaces while maintaining ease of manufacture.
Solution Approach 2:
The invention inverts the conventional approach by forming grooves on only one surface (front) instead of both surfaces. This reversal of the groove formation strategy eliminates the need for double-sided alignment while still achieving the necessary electrode connections through the oscillation arm structure.
2Manufacturing precision
If multiple exposure steps are used to form grooves and electrodes, then complete patterning is achieved, but productivity deteriorates due to increased process complexity
Solution Approach 1:
The invention merges the groove formation and electrode patterning into a single exposure process. By forming both the grooves and the electrode patterns in one exposure step on the front surface, the process complexity is reduced while maintaining manufacturing precision, thereby improving productivity.
Solution Approach 2:
The invention performs preliminary action by forming the groove patterns and electrode patterns simultaneously in the first exposure process. This preliminary formation of all necessary patterns on the front surface eliminates the need for subsequent exposure steps, streamlining the manufacturing process.
3Reliability
If grooves are formed with high precision alignment, then frequency stability is improved, but device complexity increases due to advanced exposure apparatus requirements
Solution Approach 1:
The invention extracts the alignment complexity from the exposure apparatus by eliminating the need for double-sided alignment. Forming grooves on only the front surface removes the requirement for complex double-sided projection exposure apparatus, while still achieving the frequency stability needed for reliable operation.
4Ease of manufacture
If conventional double-sided groove formation is used, then electrode connectivity is achieved, but crystal impedance stability deteriorates due to alignment variations
Solution Approach 1:
The invention extracts the alignment error source by forming grooves on only the front surface instead of both surfaces. This eliminates the alignment variations between front and rear surfaces that cause crystal impedance instability, while maintaining ease of manufacture through simplified exposure processes.
Solution Approach 2:
The invention inverts the groove formation approach from double-sided to single-sided (front surface only). This reversal eliminates the alignment variations that affect crystal impedance stability while preserving the electrode connectivity function through the oscillation arm structure.
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
The solution significantly reduces variations in resonant frequency and crystal impedance, enhancing the stability and efficiency of the crystal oscillator, while also simplifying the manufacturing process and lowering production costs.
Implementation Method 1
These electrical fields generate expansion and contraction in the oscillation arms 103a and 103b made of a crystal material to flex them.
Implementation Method 2
The tuning fork crystal oscillation piece 101a is fabricated by photolithography, chemical etching, or the like.
Data Source
AI summary
A tuning fork crystal oscillation plate includes a tuning fork crystal oscillation piece, first and second grooves, first and second groove electrodes, first side surface electrodes, and second side surface electrodes. The first groove electrode is connected to the second side surface electrodes to constitute one terminal. The second groove electrode is connected to the first side surface electrodes to constitute the other terminal. A method of manufacturing a tuning fork crystal oscillation plate is also disclosed.