Piezoelectric Resonator with Segmented Electrodes for Failure Analysis
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Solution Overview
Problem
Existing filter devices, particularly those using surface acoustic wave technology with piezoelectric substrates and interdigital transducers, are prone to destruction from excessive external power or electric charge, making it difficult to determine the cause of failure under severe conditions.
Innovation Solution
The design incorporates a resonator with a piezoelectric substrate and comb-shaped electrodes having alternating finger arrangements at different pitches, allowing for the quantitative determination of destruction by varying electrostatic capacitance in distinct regions, enabling estimation of the power or charge at the time of failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a filter uses a uniform electrode structure, then the manufacturing is simple, but the measurement precision of destruction cause is insufficient
Solution Approach 1:
The electrode structure is segmented into multiple regions with different pitches. The overlap region is divided into a first region with a first pitch and a second region with a second pitch, allowing different electrostatic capacitance values for measurement purposes while maintaining a relatively simple overall structure
Solution Approach 2:
Different regions of the electrode structure are given different local properties (different pitches) to serve specific measurement functions. The first region and second region have different pitches to create distinct electrostatic capacitance values, enabling precise determination of destruction causes in different operational conditions
2Reliability
If the electrode fingers are arranged at a single pitch, then the device complexity is low, but the reliability for determining destruction cause is insufficient
Solution Approach 1:
The electrode arrangement is segmented into multiple pitch regions. The overlap region contains a first region with a first pitch and a second region with a second pitch, creating multiple measurement zones that improve reliability by providing reference values for comparison under different operational stresses
Solution Approach 2:
The pitch parameter is changed across different regions of the electrode structure. By varying the pitch between the first region and second region, the electrostatic capacitance values differ, providing multiple reference points for reliably determining the cause of destruction based on which region is affected
3Measurement precision
If excessive power is supplied to the filter, then the testing capability is improved, but the filter is destroyed and measurement becomes impossible
Solution Approach 1:
The electrode structure is prepared in advance with multiple regions having different pitches and corresponding electrostatic capacitance values. This preliminary configuration allows the filter to serve as its own measurement instrument, enabling determination of the power level or charge amount that caused destruction by examining which region's capacitance changed
Solution Approach 2:
The destruction of the filter under excessive power or charge is converted into a beneficial measurement opportunity. By having pre-configured regions with different electrostatic capacitances, the extent and location of damage indicate the magnitude of the excessive power or charge, transforming a failure mode into a diagnostic tool
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 enables accurate determination of the cause of destruction in resonators and filter devices, reducing variations in electrostatic capacitance and phase deviations, thus enhancing reliability and sensitivity to external power or charge.
Implementation Method 1
a piezoelectric substrate and interdigital transducer (IDT) electrodes formed on the piezoelectric substrate
Implementation Method 2
surface acoustic wave devices having a piezoelectric substrate and interdigital transducer (IDT) electrodes formed on the piezoelectric substrate
Implementation Method 3
An electrostatic capacitance of the first comb-shaped electrode and the second comb-shaped electrode in the first region is about 0.9 times or more and about 1.1 times or less an electrostatic capacitance of the first comb-shaped electrode and the second comb-shaped electrode in the second region
Data Source
AI summary
A resonator includes a resonant electrode on a substrate having piezoelectricity. The resonant electrode includes a first comb-shaped electrode including a first busbar electrode and first electrode fingers, and a second comb-shaped electrode including a second busbar electrode and second electrode fingers. The substrate includes first and second overlap regions. The first region includes of pairs of first and second electrode fingers arranged alternately at a first pitch. The second region includes pairs of first and second electrode fingers arranged alternately at a second pitch different from the first pitch. An electrostatic capacitance of the first comb-shaped electrode and the second comb-shaped electrode in the first region is about 0.9 times or more and about 1.1 times or less an electrostatic capacitance of the first comb-shaped electrode and the second comb-shaped electrode in the second region.