MLCC External Electrode Insulation for Vibration Noise Reduction
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Solution Overview
Problem
Multilayer ceramic capacitors generate vibration noise due to the piezoelectric phenomenon when mounted on a wiring board, causing ambient air and the board to vibrate, leading to amplified noise.
Innovation Solution
A multilayer ceramic capacitor design featuring external electrodes with an insulating layer covering the surface except for a frame region near the outer edge, reducing the vibration caused by the piezoelectric effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an AC voltage is applied to a multilayer ceramic capacitor with perovskite dielectric, then the capacitor performs its electrical function, but vibration noise is generated due to the piezoelectric phenomenon
Solution Approach 1:
A damping layer is introduced as an intermediary component between the dielectric layers and the external environment. This damping layer absorbs the mechanical vibrations generated by the piezoelectric effect, converting them into heat energy and preventing the transmission of vibration noise to the mounting board and surrounding air, thus resolving the contradiction between maintaining electrical function and reducing harmful vibration noise
Solution Approach 2:
The piezoelectric effect that generates harmful vibration noise is converted into a beneficial mechanism by using the same effect to drive a piezoelectric actuator that actively counteracts the vibrations. The actuator generates opposing vibrations that cancel out the noise-causing vibrations through destructive interference, transforming the harmful piezoelectric phenomenon into a useful noise-cancellation mechanism
2Stability of the object's composition
If the multilayer ceramic capacitor is mounted on a wiring board, then it achieves mechanical stability, but the vibration noise is amplified through resonance of the board and ambient air
Solution Approach 1:
The damping layer serves as a mediator that decouples the vibration transmission path between the capacitor and the mounting board. By absorbing vibrations at the source before they can be transmitted to the board, the damping layer prevents the board from acting as a resonant amplifier, thus maintaining mechanical stability while eliminating the noise amplification effect
Solution Approach 2:
The damping layer provides beforehand cushioning by pre-absorbing the vibration energy generated by the piezoelectric effect before it can propagate to the mounting board and ambient air. This proactive vibration absorption prevents the subsequent resonance and amplification that would otherwise occur, addressing the noise problem at its source
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 insulating layer effectively reduces or prevents the vibration noise generated by the piezoelectric phenomenon, minimizing the expansion and contraction of the capacitor and subsequent noise amplification.
Implementation Method 1
vibration is generated by a piezoelectric phenomenon
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including dielectric layers and internal electrode layers alternately laminated, and external electrodes each on a corresponding one of end surfaces in a length direction perpendicular or substantially perpendicular to a lamination direction of the multilayer body, and each connected to the internal electrode layers. A surface, in a plan view in the length direction, of each of the external electrodes is covered with an insulating layer except for a frame region having a width of about 1 μm or more and about 100 μm or less from an outer peripheral edge of the surface.