Crystal Oscillator Orthogonal Lamination for Hysteresis Stability
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Solution Overview
Problem
The hysteresis characteristics of laminated type crystal oscillators are degraded due to stress generated from the difference in thermal expansion coefficients between the mounting substrate and the crystal unit, leading to undesirable frequency changes with temperature variations.
Innovation Solution
A crystal oscillator design where the surface mount type crystal unit and mounting substrate are laminated with orthogonal long sides, connected using a bonding material such as solder, reducing stress on the crystal element by optimizing the positional relationship and size configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the mounting substrate and crystal unit are laminated with parallel long sides (conventional configuration), then the manufacturing process is simple, but stress is generated due to thermal expansion coefficient differences, degrading hysteresis characteristics
Solution Approach 1:
The patent applies asymmetry by rotating the crystal unit 90 degrees relative to the mounting substrate, so that the long side of the crystal unit is orthogonal to the long side of the substrate. This asymmetric configuration changes the stress distribution pattern caused by thermal expansion differences, reducing the harmful stress on the crystal element while maintaining manufacturing feasibility through standard lamination processes.
2Strength
If the crystal unit and mounting substrate are connected with bonding material, then mechanical connection is achieved, but stress concentration occurs at connection points, affecting frequency stability
Solution Approach 1:
The patent applies local quality by strategically positioning the bonding material at specific locations that minimize stress concentration on the crystal element. The orthogonal configuration allows bonding material to be placed at corners or edge regions rather than directly on the crystal element, creating localized bonding zones that maintain connection strength while protecting the crystal's frequency 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
This configuration reduces stress on the crystal element, thereby improving the hysteresis characteristics of the frequency/temperature characteristics, achieving better frequency stability and manufacturing efficiency.
Implementation Method 1
The stress is caused by the difference of thermal expansion coefficients between the mounting substrate and the crystal unit
Data Source
AI summary
A crystal oscillator includes a surface mount type crystal unit and a mounting substrate. The surface mount type crystal unit includes a ceramic container. The surface mount type crystal unit has a rectangular shape as a planar shape. The mounting substrate includes a ceramic substrate on which an electronic component is mounted, the mounting substrate having a rectangular shape as a planar shape. The crystal oscillator has a structure where the surface mount type crystal unit and the mounting substrate are laminated, and both terminals of the surface mount type crystal unit and the mounting substrate are connected with a bonding material. The mounting substrate and the surface mount type crystal unit are connected in a positional relationship where a long side of the mounting substrate and a long side of the surface mount type crystal unit are orthogonal.