Piezoelectric Oscillator Wire Shielding for Frequency Stability
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Solution Overview
Problem
Existing piezoelectric oscillators suffer from increased parasitic capacitances between wires, leading to deteriorated frequency-power characteristics due to fluctuations in output frequency relative to power supply voltage.
Innovation Solution
A vibrator device with a shield wire placed between first and second wires to reduce parasitic capacitances, featuring a base, semiconductor element, and vibrator stacked sequentially, with the shield wire electrically coupling between the excitation electrode and semiconductor element, and between the external output terminal and semiconductor element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the piezoelectric vibrator, IC chip, and substrate are placed in upward and downward directions to downsize the oscillator, then the device size is reduced, but the distances between wires are smaller causing increased parasitic capacitances and deteriorated frequency-power characteristics
Solution Approach 1:
A shield wire is introduced as an intermediary element positioned between the first wire (coupling piezoelectric vibrator to IC chip) and the second wire (coupling output terminal to IC chip). This shield wire acts as a mediator that reduces parasitic capacitance between the two wires, thereby improving frequency-power characteristics while maintaining the compact stacked configuration
2Length of moving object
If wires are placed closer together to reduce device size, then the device is downsized, but parasitic capacitance between wires increases causing larger fluctuations in output frequency relative to power supply voltage
Solution Approach 1:
The shield wire serves as a protective intermediary positioned between the first and second wires. It reduces the parasitic capacitance between these wires through electromagnetic shielding, thereby stabilizing the output frequency relative to power supply voltage fluctuations while allowing the wires to remain in close proximity for compact design
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 shield wire reduces parasitic capacitance differences, resulting in smaller fluctuations of output frequency relative to power supply voltage, providing improved frequency-power characteristics.
Implementation Method 1
parasitic capacitances produced between the pair of wires for oscillating the piezoelectric vibrator and the wire for outputting the output signal increase
Implementation Method 2
a piezoelectric oscillator (vibrator device) in which a piezoelectric vibrator and an IC chip as a circuit for oscillating the piezoelectric vibrator
Data Source
AI summary
A vibrator device has a base, a semiconductor element having an oscillation circuit, and a vibrator having an excitation electrode sequentially stacked and includes a first wire electrically coupling between the excitation electrode and the semiconductor element, a second wire electrically coupling between a second external terminal as an external output terminal placed on the base and the semiconductor element, and a shield wire placed between at least a part of the first wire and at least a part of the second wire.