Piezoelectric Resonator Electrode Layout for Stable Conductive Bonding
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Solution Overview
Problem
Miniaturization of resonator devices poses challenges in maintaining a stable conduction state due to the instability of lead electrodes when bonded with conductive adhesive, particularly as the electrodes become smaller.
Innovation Solution
A resonator device design featuring a piezoelectric substrate with excitation and extension electrodes, a case with a protruding inner wall, and a conductive adhesive that bonds the extension electrodes to the case's inner walls, increasing the contact area and stability of the conduction state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the lead electrode is miniaturized to reduce device size, then the resonator device achieves miniaturization, but the conduction state becomes unstable when bonded with conductive adhesive
Solution Approach 1:
The extension electrode extends from the first surface to the side surface of the piezoelectric substrate, transitioning the bonding interface from a single-point contact to a multi-dimensional contact that includes side surface electrodes. This dimensional extension increases the contact area between the electrode and conductive adhesive without increasing the footprint area, thereby maintaining conduction stability while achieving miniaturization.
Solution Approach 2:
The extension electrode is divided into multiple segments: a first side surface electrode on the first side surface and a second side surface electrode on the second side surface. This segmentation allows the conductive adhesive to bond at multiple discrete locations, distributing the bonding stress and improving overall conduction reliability even when the device is miniaturized.
2Reliability
If the contact area between lead electrode and conductive adhesive is increased to improve conduction stability, then the bonding strength increases, but the device size increases
Solution Approach 1:
Instead of increasing the contact area in the planar direction (which would increase device footprint), the extension electrode utilizes the vertical dimension by extending to the side surface. This allows the conductive adhesive to access and bond with the electrode at the side surface, effectively increasing the bonding area without increasing the device's planar dimensions.
Solution Approach 2:
The extension electrode creates localized bonding regions at specific locations: the first side surface electrode at one side and the second side surface electrode at the opposite side. This localized quality approach concentrates the bonding strength at critical points while keeping the overall device size compact, rather than distributing a large bonding area across the entire device.
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 design enhances the reliability of electrical coupling between the resonator element and the case, stabilizes the conduction state, and increases the bonding strength between the case and the lead electrodes, thereby improving the overall reliability of the resonator device.
Implementation Method 1
a conductive adhesive bonding the extension electrode and the coupling electrode
Implementation Method 2
a piezoelectric substrate; an excitation electrode formed at the piezoelectric substrate
Data Source
AI summary
Provided is a resonator device in which an inner wall of a case accommodating a piezoelectric substrate includes a first inner wall and a second inner wall that intersect at a corner at which a coupling electrode is located, the piezoelectric substrate has a first surface facing a bottom surface of the case, a second surface opposite to the first surface, a first side surface facing the first inner wall, and a second side surface facing the second inner wall, an extension electrode formed at the piezoelectric substrate includes a first side surface electrode overlapping the first side surface and a second side surface electrode overlapping the second side surface, a conductive adhesive reaches the first side surface electrode and the second side surface electrode of the piezoelectric substrate from the coupling electrode formed at the case, bonds the first side surface electrode and the first inner wall, and bonds the second side surface electrode and the second inner wall.