Piezoelectric Drive Apparatus Substrate Orientation
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Solution Overview
Problem
Piezoelectric drive apparatuses using thin-film piezoelectric elements often face challenges in achieving high output due to insufficient displacement and efficiency, particularly when the piezoelectric body layer thickness is limited, leading to potential dielectric breakdown or cracking issues.
Innovation Solution
A piezoelectric drive apparatus is designed with a substrate having a specific orientation where the longitudinal direction coincides with the direction of minimized Young's modulus or maximized shear elastic coefficient, allowing for large displacement bending vibrations when voltage is applied, and incorporating a piezoelectric element with electrodes on a silicon single crystal substrate, which enhances output and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a thin-film piezoelectric element is used to reduce the size of the piezoelectric drive apparatus, then the size is reduced, but the output becomes insufficient
Solution Approach 1:
The patent changes the substrate orientation parameter from conventional directions to a specific direction where Young's modulus is minimized. This parameter change allows the thin-film piezoelectric element to generate larger displacement and bending vibration amplitude, thereby increasing output while maintaining the compact size advantage of thin-film elements.
2Power
If the piezoelectric body layer thickness is increased to improve output, then output is improved, but dielectric breakdown or cracking issues occur
Solution Approach 1:
Instead of increasing piezoelectric body layer thickness, the patent changes the substrate orientation parameter to minimize Young's modulus in the longitudinal direction. This allows achieving larger displacement and output with the same or reduced piezoelectric body thickness, avoiding dielectric breakdown and cracking issues while maintaining reliability.
3Power
If a bulk piezoelectric element is used to achieve high output, then output is improved, but the size of the piezoelectric drive apparatus increases
Solution Approach 1:
The patent uses a thin-film piezoelectric element with optimized substrate orientation (minimizing Young's modulus) to achieve large displacement and high output. This resolves the contradiction by proving that thin-film elements can provide high output comparable to bulk elements while maintaining significant size advantages.
4Length of moving object
If the substrate orientation is optimized to maximize displacement, then displacement is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a particular substrate orientation where Young's modulus is minimized. This is a well-defined crystallographic direction that can be controlled during substrate fabrication and mounting, making the optimization practical and manufacturable while achieving maximum displacement.
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 approach results in a piezoelectric drive apparatus capable of providing high output and improved efficiency by optimizing substrate orientation and material properties, avoiding issues like dielectric breakdown and cracking, and enabling efficient rotation of a rotor.
Implementation Method 1
A piezoelectric element provided on the substrate has a first electrode, a second electrode, and a piezoelectric body positioned between the first electrode and the second electrode
Implementation Method 2
the longitudinal direction of the substrate roughly coincides with a direction in which Young's modulus is minimized in a plane of the substrate
Data Source
AI summary
A piezoelectric drive apparatus for a motor, the apparatus including a substrate having a longitudinal direction and a widthwise direction perpendicular to the longitudinal direction, a piezoelectric element provided on the substrate and having a first electrode, a second electrode, and a piezoelectric body positioned between the first electrode and the second electrode, and a contact section that is attached to a front end section of the substrate in the longitudinal direction thereof or in contact with the front end section of the substrate in the longitudinal direction thereof and comes into contact with a driven body, wherein the longitudinal direction of the substrate roughly coincides with a direction in which Young's modulus is minimized in a plane of the substrate.