Multilayered Ceramic Capacitor Lower Cover Layer Segmentation
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Solution Overview
Problem
Multilayered ceramic capacitors generate acoustic noise due to piezoelectric vibrations, and existing solutions that enlarge the lower cover layer to reduce noise increase equivalent series inductance (ESL), which is undesirable.
Innovation Solution
A multilayered ceramic capacitor design with a thicker lower cover layer and internal electrodes within it, maintaining ESL at a predetermined level while reducing acoustic noise by controlling the thickness ratios and internal electrode placement to minimize vibration-induced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the lower cover layer is enlarged to reduce acoustic noise, then acoustic noise is reduced, but equivalent series inductance (ESL) increases
Solution Approach 1:
The lower cover layer is segmented into multiple sections: a first lower cover layer portion with a first thickness and a second lower cover layer portion with a second thickness greater than the first thickness. This segmentation allows different regions to serve different functions - the thinner portion maintains lower ESL while the thicker portion reduces acoustic noise vibrations.
Solution Approach 2:
Different thicknesses are applied to different portions of the lower cover layer based on local requirements. The first lower cover layer portion has a smaller thickness optimized for electrical performance, while the second lower cover layer portion has a larger thickness optimized for acoustic noise reduction, creating local quality variations to resolve the contradiction.
2Object-affected harmful factors
If the lower cover layer thickness is increased to suppress vibrations, then acoustic noise is reduced, but the overall device height and ESL increase
Solution Approach 1:
The lower cover layer is divided into portions with different thicknesses, allowing vibration suppression in specific areas without uniformly increasing the overall device height. The first lower cover layer portion maintains smaller thickness while the second portion provides targeted vibration suppression where needed.
Solution Approach 2:
The thickness of the lower cover layer is locally optimized - the first lower cover layer portion has a thickness suitable for maintaining compact dimensions, while the second lower cover layer portion has increased thickness specifically where vibration suppression is required, achieving local quality enhancement without global dimension increase.
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 design effectively reduces acoustic noise to below 20 dB while maintaining ESL at a suitable level, preventing capacitance defects and ensuring reliable performance.
Implementation Method 1
Since the plurality of dielectric layers have both piezoelectric and electrostrictive properties, a piezoelectric phenomenon may occur, causing vibrations among the internal electrodes when AC or DC voltage is applied to the multilayered ceramic capacitor.
Implementation Method 2
Since the plurality of dielectric layers have both piezoelectric and electrostrictive properties, a piezoelectric phenomenon may occur, causing vibrations among the internal electrodes when AC or DC voltage is applied to the multilayered ceramic capacitor.
Data Source
AI summary
There is provided a multilayered ceramic capacitor, including: a ceramic body; an active layer including a plurality of first and second internal electrodes; an upper cover layer; a lower cover layer formed below the active layer, the lower cover layer being thicker than the upper cover layer; first and second external electrodes; at least one pair of first and second internal electrodes repeatedly formed inside the lower cover layer, wherein, when A is defined as ½ of an overall thickness of the ceramic body, B is defined as a thickness of the lower cover layer, C is defined as ½ of an overall thickness of the active layer, and D is defined as a thickness of the upper cover layer, a ratio of deviation between a center of the active layer and a center of the ceramic body, (B+C)/A, satisfies 1.063≤(B+C)/A≤1.745.