Multilayer Piezoelectric Device with Central Insulating Layer
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Solution Overview
Problem
Existing piezoelectric devices face challenges in optimizing energy harvesting and sensor performance due to limitations in layer configuration, electrode connectivity, and material mismatch, which affect displacement, blocked force, and efficiency in energy conversion and sensing applications.
Innovation Solution
A multilayer piezoelectric device configuration with a specific layer structure and electrode arrangement, including an insulating layer positioned at the vertical center, and electrically connected middle electrodes, enhances energy harvesting and sensing capabilities by optimizing displacement and blocked force through improved strain and electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple piezoelectric layers are stacked to increase energy harvesting, then energy harvesting efficiency is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The piezoelectric device is divided into multiple discrete layers (first piezoelectric layer, second piezoelectric layer, third piezoelectric layer) with distinct functions. Each layer can be independently optimized and manufactured, then assembled into the complete device. This segmentation allows for increased energy harvesting capability through multiple layers while managing complexity through modular design.
Solution Approach 2:
The device employs composite material structure combining piezoelectric materials with other functional materials (electrodes, insulating layers, proof mass materials). This composite approach enables each layer to contribute specific properties (piezoelectric effect, electrical conduction, mechanical support) while working together to achieve enhanced overall energy harvesting performance.
2Volume of moving object
If piezoelectric layers are made thinner to reduce device size, then device volume is reduced, but strain distribution and energy conversion efficiency deteriorate
Solution Approach 1:
The patent transitions from a single thick piezoelectric layer to multiple thin layers stacked in the vertical dimension. This dimensional change allows the device to maintain a compact volume while distributing strain across multiple interfaces. The cumulative effect of strain across multiple thin layers achieves energy conversion efficiency comparable to or exceeding that of a single thick layer.
3Power
If different materials are used for piezoelectric layers to optimize performance, then energy harvesting is improved, but thermal expansion mismatch increases
Solution Approach 1:
The patent applies local quality optimization by selecting specific piezoelectric materials for specific layers based on their functional requirements. The first, second, and third piezoelectric layers can use different materials optimized for their local stress and electric field conditions, while the overall device maintains thermal stability through careful material selection and layer configuration.
4Power
If complex electrode arrangements are used to improve electrical connectivity, then energy harvesting is improved, but manufacturing precision requirements increase
Solution Approach 1:
The electrode system is segmented into distinct first and second electrodes that are separately formed on opposite surfaces of the piezoelectric structure. This segmentation simplifies the manufacturing process compared to forming complex interconnected electrode patterns, as each electrode can be independently deposited and aligned without requiring high-precision multi-step patterning.
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 proposed configuration increases energy harvesting efficiency and sensor performance by enhancing strain in thinner piezoelectric layers, reducing electrode material requirements, and facilitating easier electrical connections, while minimizing thermal expansion mismatches.
Implementation Method 1
Piezoelectricity is an energy conversion manner by which electrical and mechanical energies can be directly converted to each other. When a voltage is applied to a piezoelectric material, the material experiences stress or changes shape. Similarly, when mechanical energy is applied to a piezoelectric material, an electrical voltage is generated across the material.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Piezoelectric devices are provided. A device can include a top electrode, a first piezoelectric layer having an upper surface disposed on a lower surface of the top electrode, a first center electrode having an upper surface disposed on a lower surface of the first piezoelectric layer, an insulating layer having an upper surface disposed on a lower surface of the first center electrode, a second center electrode having an upper surface disposed on a lower surface of the insulating layer, a second piezoelectric layer having an upper surface disposed on a lower surface of the second center electrode, and a bottom electrode having an upper surface disposed on a lower surface of the second piezoelectric layer. The insulating layer can be positioned substantially at a vertical center of the piezoelectric device. The first center electrode can be electrically connected to the second center electrode.