Tuning Fork Piezoelectric Electrode Routing for Stable Miniaturization
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Solution Overview
Problem
Miniaturized tuning fork-type piezoelectric vibration pieces face challenges in forming adequately large penetrating holes due to crystal anisotropy and wet etching variability, leading to unstable electrical conduction and potential breakage of connections.
Innovation Solution
The design includes through electrodes with a substantially circular shape on the stem portion and routing wirings through the crotch part between vibrating arms, ensuring reliable electrical conduction between main surface electrodes on front and back sides, even in miniaturized devices, by forming a stable connection path that mitigates production variability and misregistration issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the vibration piece is miniaturized, then the device size is reduced, but the opening size of penetrating holes becomes smaller and electrical conduction becomes unstable
Solution Approach 1:
The patent transitions from planar electrode connections to three-dimensional routing through the crotch part and side surfaces. The routing wiring extends from the front main surface, through the crotch part between vibrating arms, to the side surface of the vibrating arm, creating a spatial path that bypasses the limited opening area of penetrating holes.
Solution Approach 2:
The crotch part between the vibrating arms serves as an intermediary structure that houses the routing wiring. This intermediate space allows electrical connections to be established without relying solely on the penetrating hole openings, providing a stable connection path that is independent of opening size variations.
2Ease of manufacture
If wet etching is used to form penetrating holes, then the holes can be formed in the crystal, but the opening size varies due to crystal anisotropy and etching variability
Solution Approach 1:
The patent designs the routing wiring to extend beyond the peripheral area of penetrating holes and utilize the crotch part as a backup connection path. This preliminary design compensates for potential conduction failures that may occur due to variability in penetrating hole opening sizes, ensuring reliable electrical connection even when etching results vary.
3Volume of moving object
If the opening area of penetrating holes is small, then the device can be miniaturized, but electrical conduction becomes unstable and connections may break
Solution Approach 1:
The routing wiring creates a three-dimensional connection path that extends from the front main surface through the crotch part to the side surface of the vibrating arm. This spatial routing provides additional connection strength and stability that is independent of the penetrating hole opening area, allowing the device to be miniaturized without compromising connection reliability.
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 approach prevents conduction failure and enhances the stability of characteristics in miniaturized tuning fork-type piezoelectric vibration pieces, ensuring reliable electrical connections and maintaining performance within frequency specifications.
Implementation Method 1
tuning fork-type piezoelectric vibration piece
Data Source
AI summary
Main surface electrodes formed on main surfaces on front and back sides of vibrating arms are electrically coupled via through electrodes formed in a stem portion so as to penetrate through front and back surfaces thereof. One of the main surface electrodes of the vibrating arm is electrically coupled to side surface electrodes through a routing wiring formed by way of a crotch part between roots of the vibrating arms, and the one of the main surface electrodes is further electrically coupled to the other one of the main surface electrodes through the side surface electrodes.