Multilayer Capacitor Buffer Layer Groove Vibration Isolation
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Solution Overview
Problem
Multilayer ceramic capacitors generate acoustic noise due to piezoelectric vibrations when mounted on electronic device boards, causing discomfort and requiring a solution to reduce this noise while maintaining performance and durability.
Innovation Solution
A multilayer capacitor design featuring a buffer layer with dummy electrodes and grooves on its lower surface, which reduces vibration transmission by creating an air layer and enhancing adhesion to the board, thereby minimizing acoustic noise and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multilayer capacitor is mounted in a high density manner to increase component mounting density, then the component mounting density is improved, but acoustic noise increases due to heat and vibrations generated by interactions between components
Solution Approach 1:
A buffer layer is introduced as an intermediary between the multilayer capacitor and the circuit board. This buffer layer includes a groove that creates an air layer, serving as a mediator to reduce vibration transmission from the capacitor to the board, thereby decreasing acoustic noise while allowing high-density mounting
2Reliability
If the dielectric layers are made with piezoelectric properties to achieve high capacitance, then the capacitance performance is improved, but piezoelectric vibrations are generated causing acoustic noise
Solution Approach 1:
The piezoelectric effect, which generates vibrations and acoustic noise, is not eliminated but managed. The buffer layer with groove structure converts the harmful vibration energy into beneficial stress dispersion, allowing the piezoelectric properties to maintain high capacitance performance while reducing the harmful acoustic noise through controlled stress distribution
3Object-generated harmful factors
If a buffer layer with groove is added to reduce vibration transmission, then acoustic noise is reduced, but the device structure becomes more complex
Solution Approach 1:
The buffer layer is segmented by introducing a groove that divides it into regions, creating an air layer that acts as a vibration barrier. This segmentation approach reduces acoustic noise transmission while maintaining a relatively simple overall structure, as the groove can be formed through standard manufacturing processes
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 design effectively reduces acoustic noise and enhances the durability and reliability of multilayer capacitors by dispersing piezoelectric stress and improving adhesion to the board, leading to improved performance in electronic devices.
Implementation Method 1
since the dielectric layers have piezoelectric properties, when a direct current voltage or an alternating current voltage is applied to the multilayer ceramic capacitor, a piezoelectric phenomenon may be generated between the internal electrodes, such that a volume of a ceramic body is expanded and contracted according to a frequency
Implementation Method 2
a groove is recessed in a lower surface of the buffer layer... reduces vibration transmission by creating an air layer
Data Source
AI summary
A multilayer capacitor includes a body including a plurality of dielectric layers, an active region and upper and lower cover regions; first and second internal electrodes disposed with the dielectric layer interposed therebetween in the active region to be alternately exposed through both end surfaces of the body; and first and second external electrodes disposed on both ends of the body and connected to the first and second internal electrodes, respectively. The body further includes a buffer layer including first and second dummy electrodes disposed on a lower surface of the lower cover region to be spaced apart from each other in a length direction of the body, and a groove is recessed in a lower surface of the buffer layer.