Multi-layered ceramic capacitor and method of manufacturing the same
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving high reliability and durability, particularly in harsh environments with high temperatures and humidity, as well as mechanical strength to withstand bending deformation and vibrations, which conventional methods have not adequately addressed.
Innovation Solution
The development of a multilayer ceramic capacitor design that includes a ceramic body with a dielectric layer and internal electrodes, along with a cover portion having a higher number of pores than the dielectric layer, filled with a ceramic-polymer composite to enhance bending strength and moisture resistance reliability, and a method of manufacturing involving the alternation of ceramic green sheets with different compositions to form a laminated body and apply a polymer paste to the cover portion after sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ceramic body is made denser to improve electrical insulation, then moisture resistance improves, but bending strength decreases
Solution Approach 1:
The patent applies different density characteristics to different regions of the ceramic body. The active portion (capacitor portion) maintains high density for electrical insulation, while the cover portion intentionally has lower density with more pores to provide bending strength. This local differentiation resolves the contradiction by allowing each region to optimize for its specific function.
Solution Approach 2:
The patent creates a composite structure where the ceramic body combines dense dielectric material in the active portion with a porous ceramic-polymer composite in the cover portion. The polymer infiltration into pores of the cover portion creates a composite material that provides both mechanical strength and maintains electrical insulation, resolving the contradiction between density-related insulation and strength.
2Strength
If the cover portion has more pores to improve bending strength, then mechanical durability improves, but electrical insulation may deteriorate
Solution Approach 1:
The patent uses polymer material as an intermediary substance that fills the pores in the cover portion. This polymer acts as a mediator that maintains electrical insulation in the porous region, allowing the cover portion to have high porosity for bending strength while preventing electrical conductivity issues through the polymer's insulating properties.
Solution Approach 2:
The patent changes the physical and chemical parameters of the cover portion by infiltrating polymer into the pores. This parameter change transforms the porous ceramic structure into a ceramic-polymer composite with modified electrical and mechanical properties, allowing high porosity to coexist with good electrical insulation.
3Strength
If polymer is applied to the cover portion to fill pores, then bending strength improves, but manufacturing complexity increases
Solution Approach 1:
The patent performs the polymer infiltration action after the sintering process, when the porous structure is already formed. This preliminary creation of the porous structure during sintering, followed by subsequent polymer application, simplifies the overall process by separating the formation of mechanical strength structure from the electrical insulation enhancement, making the manufacturing more manageable.
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 design improves bending strength and moisture resistance reliability by creating a ceramic-polymer composite structure in the cover portions, while maintaining capacitance performance and preventing electrical conductivity issues that can lower reliability.
Implementation Method 1
a paste including a polymer is applied to the cover portion to fill the pores of the cover portion with the polymer
Implementation Method 2
A ceramic body is prepared including dielectric layers and first and second internal electrodes by sintering the laminated body
Data Source
AI summary
A multilayer ceramic capacitor includes a ceramic body including a dielectric layer and first and second internal electrodes disposed to oppose each other with the dielectric layer interposed therebetween, and first and second external electrodes disposed outside of the ceramic body and connected to the first and second internal electrodes, respectively. The ceramic body includes an active portion including of the first and second internal electrodes disposed to oppose each other with the dielectric layer interposed therebetween to form capacitance, and a cover portion disposed in upper and lower portions of the active portion. The cover portion has a larger number of pores than the dielectric layer of the active portion, and the cover portion includes a ceramic-polymer composite filled with a polymer in the pores of the cover portion.