Multilayer Capacitor Electrode Segmentation for Strain Reduction
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Solution Overview
Problem
Multilayer capacitors experience mechanical strains due to electrostrictive effects, leading to vibrations and noise when mounted on boards, particularly at the contact points between the capacitor and the board, which are not effectively mitigated by existing technologies.
Innovation Solution
The design incorporates a capacitor body with inner electrodes and terminal electrodes where the first inner electrode includes a no-capacity generating region that overlaps with the lead electrode portion, reducing the electrostrictive effect's influence on the terminal electrodes, and the terminal electrodes are set shorter than the corresponding surfaces to minimize mechanical strain propagation to the mounting board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitor body has a dielectric characteristic with electrostrictive effect, then capacitance function is achieved, but mechanical strain and vibration occur near terminal electrodes
Solution Approach 1:
The inner electrode is divided into three distinct regions: capacity generating region, no-capacity generating region, and lead electrode portion. This segmentation allows different parts of the electrode to serve different functions - storing charge, reducing electrostrictive effect, and providing electrical connection - thereby resolving the contradiction between achieving capacitance and minimizing mechanical strain.
Solution Approach 2:
The no-capacity generating region is strategically positioned between the capacity generating region and the terminal electrode, creating a localized zone with different electrical characteristics. This local modification reduces the electric field intensity and electrostrictive effect specifically in the region near the terminal electrode, while maintaining full capacitance function in the capacity generating region.
2Reliability
If terminal electrodes are made longer to improve electrical connection, then electrical conductivity is improved, but mechanical strain propagation to mounting board increases
Solution Approach 1:
The electrode structure is segmented into functional regions with the lead electrode portion being shorter than the full electrode length. This segmentation allows the electrical connection function to be fulfilled by the lead portion while the no-capacity generating region acts as an isolation zone, preventing strain propagation to the mounting board.
Solution Approach 2:
The no-capacity generating region serves as an intermediary zone between the capacity generating region and the terminal electrode. This intermediate region reduces the transmission of mechanical strain from the capacitor body to the terminal electrode and subsequently to the mounting board, while still allowing electrical connectivity.
3Object-affected harmful factors
If no-capacity generating region is added to inner electrode, then electrostrictive effect is reduced, but electrode structure complexity increases
Solution Approach 1:
The inner electrode is segmented into three regions that can be formed using standard multilayer capacitor manufacturing processes. Each region has a distinct function but the overall structure follows conventional electrode patterns, making the design practical for mass production while achieving reduced electrostrictive effect.
Solution Approach 2:
Rather than fundamentally changing the electrode structure, the invention introduces a local modification - the no-capacity generating region - that has specific dimensions and positioning. This localized approach reduces complexity compared to complete structural redesign while effectively mitigating the electrostrictive effect.
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 effectively suppresses mechanical strains near the terminal electrodes, reducing vibrations and noise when a voltage is applied, by distributing the electrostrictive effects and enhancing interlayer adhesion, thus preventing strain propagation to the mounting board.
Implementation Method 1
there occurs a problem that a mechanical strain having a magnitude proportional to the applied voltage is caused in the capacitor body because of the electrostrictive effect
Data Source
AI summary
A multilayer capacitor having a capacitor body, first and second inner electrodes, and first and second terminal electrodes. A first terminal electrode is arranged on a first surface of the capacitor body which is parallel to a first direction, and connected to the first inner electrode. A second terminal electrode is connected to the second inner electrode. The first inner electrode has a first main electrode portion including a first no-capacity generating region and a first capacity generating region, and a first lead electrode portion. In a second direction, the first terminal electrode is set smaller than the first surface, while the first lead electrode portion is set smaller than the first main electrode portion. The first no-capacity generating region and the first lead electrode portion overlap each other in the second direction when seen in the first direction.