Piezoelectric Shear Stack Using Discrete Conductive Pillars
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Solution Overview
Problem
Conventional piezoelectric stacks face challenges in reducing driving voltage while maintaining driving level, especially in high-frequency applications, due to clamping effects from bonding layers, which degrade transducer performance in shear mode operations.
Innovation Solution
A piezoelectric stack design using discrete conductive epoxy pillars to minimize clamping effects, with a bonding layer structure that includes multiple discrete pillars or areas of conductive adhesive epoxy, reducing the overall clamping impact and maintaining structural strength and electrical connection between crystal elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding layers are used to bond piezoelectric elements in a stack, then structural strength is maintained, but clamping effects increase which degrades transducer performance in shear mode operations
Solution Approach 1:
The bonding layer is segmented into discrete conductive epoxy pillars rather than a continuous layer. This segmentation reduces the clamping effect on the piezoelectric elements while maintaining structural integrity and electrical connectivity at critical points, thereby improving transducer performance in shear mode operations.
Solution Approach 2:
The bonding structure transitions from uniform continuous bonding to non-uniform localized bonding with discrete pillars. The pillars are strategically positioned to provide necessary mechanical support and electrical connection only where required, reducing unnecessary clamping effects on the active piezoelectric material areas.
2Reliability
If discrete conductive epoxy pillars are used to minimize clamping effects, then transducer performance is improved, but bonding area is reduced which may compromise structural strength
Solution Approach 1:
The bonding structure uses a composite approach combining discrete conductive epoxy pillars with the piezoelectric elements. The pillars are made of conductive epoxy material that provides both mechanical bonding and electrical connectivity, creating a multi-functional composite structure that maintains strength while reducing clamping effects.
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 design achieves reduced driving voltage while maintaining the same driving level, enhancing the performance of piezoelectric d36 shear crystal stacks by minimizing clamping effects and ensuring adequate bonding strength, suitable for high-sensitivity transducer applications.
Implementation Method 1
piezoelectric d36 shear crystal stacks
Implementation Method 2
discrete conductive epoxy pillars to form a shear crystal stack structure
Data Source
AI summary
A system and method provides a piezoelectric stack arrangement for reduced driving voltage while maintaining a driving level for active piezoelectric materials. A stack arrangement of d36 shear mode <011>single crystals of both air X-cut and Y-cut ±1:45° (±20°) arrangement are bonded with discrete conductive pillars to form a shear crystal stack. The bonding area between the neighboring crystal parts is minimized. The bonding pillars are positioned at less than a total surface are of the single crystal forming the stack. The stack fabrication is facilitated with a precision assembly system, where crystal parts are placed to desired locations on an assembly fixture for alignment following the preset operation steps. With the reduced clamping effect from bonding due to lower surface coverage of the discrete conductive pillars, such a piezoelectric d36 shear crystal stack exhibits a reduced driving voltage while maintaining a driving level and substantial and surprisingly improved performance.