Elastic Wave Resonator Layout to Block IDT-Inductor Interference
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Solution Overview
Problem
Conventional elastic wave devices suffer from interference between the IDT electrode and the conductor pattern formed to obtain inductance, which deteriorates the device's properties.
Innovation Solution
The elastic wave device incorporates an insulation protector to interpose between the IDT electrode and the conductor pattern, preventing interference by optimizing the distance and configuration between the top panel and the conductor pattern, and using a photosensitive polyimide resin for the support pillar and adhesion layer to enhance mechanical strength and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conductor pattern is formed on the top panel to obtain inductance, then attenuation characteristics are improved, but interference occurs between the IDT electrode and the conductor pattern which deteriorates device properties
Solution Approach 1:
The patent introduces an insulation protector as an intermediary layer between the IDT electrode and the conductor pattern. This insulation protector is formed on the top panel in a region overlapping with the IDT electrode, effectively blocking the electromagnetic coupling and interference between these two components while allowing the conductor pattern to maintain its inductance function for improving attenuation characteristics
2Volume of moving object
If the conductor pattern is placed close to the IDT electrode to reduce device size, then miniaturization is achieved, but interference between the IDT electrode and conductor pattern increases
Solution Approach 1:
The insulation protector serves as a mediator that enables close placement of the conductor pattern near the IDT electrode without causing harmful interference. By positioning the insulation protector between these components, the device can be miniaturized while the insulation layer prevents electromagnetic coupling that would otherwise occur at close distances
3Reliability
If the insulation protector is positioned to cover the IDT electrode region, then interference is prevented, but the inductance component may be affected
Solution Approach 1:
The insulation protector is selectively positioned only in the region where it is needed to prevent interference - specifically on the top panel in the area overlapping with the IDT electrode. This localized placement prevents harmful electromagnetic coupling while leaving other regions open to maintain the conductor pattern's inductance function, thus achieving local quality optimization
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 effectively inhibits interference, improving the Q-value and inductance components of the elastic wave device, enhancing its reliability and performance by reducing coupling effects between the inductance component and the top panel.
Implementation Method 1
elastic wave device which utilizes a wave propagating on its surface... piezoelectric substrate 102, IDT electrode 103
Data Source
AI summary
An elastic wave device includes a piezoelectric substrate, an IDT electrode disposed on the piezoelectric substrate, an internal electrode disposed on the piezoelectric substrate and connected to the IDT electrode, a support pillar disposed on the piezoelectric substrate and provided around the IDT electrode, a top panel provided on the support pillar to cover a space above the IDT electrode, an insulation protector provided to cover the support pillar and the top panel, an external electrode disposed on the insulation protector, a conductor pattern disposed on the insulation protector in order to obtain inductance, and a connection electrode provided through the insulation protector, to connect the external electrode and the internal electrode to each other.