Electretized Comb Tooth Energy Harvester With High Aspect Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional vibration-driven energy harvesting elements require increasing the surface area of comb tooth electrodes to enhance power generation, which leads to a larger size and bulkiness, making it challenging to increase power output while maintaining a compact design.
Innovation Solution
A vibration-driven energy harvesting element with a three-terminal structure featuring electretized comb teeth and a gap dimension between the comb teeth smaller than 20 μm, along with an aspect ratio of 20 or more, allowing for increased power generation without expanding the device's size, utilizing a silicon oxide film with permanent charge and an electret protective film for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the surface area of comb tooth electrodes is increased by increasing the number of comb tooth electrodes, then the generated power increases, but the device size increases
Solution Approach 1:
The patent changes the geometric parameters of the comb tooth electrodes, specifically reducing the gap dimension to less than 20 μm and increasing the aspect ratio to 20 or more. This parameter optimization allows the electrodes to generate sufficient power without increasing the overall device volume, resolving the contradiction between power generation and device size.
Solution Approach 2:
The patent emphasizes the importance of the aspect ratio (dimension in comb tooth height direction relative to gap dimension) by making it 20 or more. This dimensional optimization in the vertical direction compensates for the reduced gap dimension, enabling high power generation in a compact footprint without expanding the device horizontally.
2Power
If the gap dimension between comb teeth is reduced to increase power density, then the aspect ratio increases and power generation improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a gap dimension of less than 20 μm and an aspect ratio of 20 or more, which are optimized parameters that balance power generation performance with manufacturability. These parameter ranges are set to achieve high power density while remaining feasible with standard MEMS fabrication capabilities.
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 configuration enables increased power generation while maintaining a compact size, achieving a 6.4 times power increase with a larger aspect ratio, effectively addressing the limitations of conventional designs by optimizing the comb tooth structure and electretization.
Implementation Method 1
a silicon oxide film containing a permanent charge is formed at a surface of at least either the fixed comb teeth or the movable comb teeth
Implementation Method 2
the vibration-driven energy harvesting element has a three-terminal structure in which the fixed comb teeth and/or the movable comb teeth are electretized
Data Source
AI summary
A vibration-driven energy harvesting element includes: a pair of fixed electrode portions that have a plurality of fixed comb teeth and are arranged such that the plurality of fixed comb teeth face each other; and a movable electrode portion that is arranged between the pair of fixed electrode portions and has a pair of a plurality of movable comb teeth being inserted between the fixed comb teeth of the respective fixed electrode portions, wherein: the vibration-driven energy harvesting element has a three-terminal structure in which the fixed comb teeth and/or the movable comb teeth are electretized; a gap dimension of a clearance region between the fixed comb teeth and the movable comb teeth is smaller than 20 μm; and an aspect ratio being a ratio of a dimension of the clearance region in a comb tooth height direction to the gap dimension of the clearance region, is 20 or more.