Multilayer Ceramic Capacitor End Structure for Moisture Resistance
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Solution Overview
Problem
Conventional multilayer ceramic capacitors are prone to moisture resistance issues due to air bubbles forming at the step portion between the inner and outer layer portions, which affects their performance.
Innovation Solution
The design incorporates an obtuse angle between the outer layer end surfaces and the coupling surfaces, with inner conductor layers exposed on these surfaces, and a protruding end surface that extends beyond the outer layer end surfaces, enhancing moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inner layer portion protrudes from the element body at a right angle step portion, then the terminal electrode can be more suitably formed, but air bubbles are more likely to form in the external electrode disposed in the step portion leading to poor moisture resistance
Solution Approach 1:
The invention replaces the right angle step portion with a curved coupling surface that has a specific radius of curvature (R1 and R2). This curved transition between the inner layer portion and outer layer portion eliminates the sharp corner where air bubbles would accumulate, while still allowing the terminal electrode to be properly formed. The curved surface ensures smooth material flow during sintering and prevents void formation, thereby maintaining both manufacturability and moisture resistance.
2Device complexity
If a right angle step portion is formed between inner and outer layer portions, then structural definition is simplified, but air bubble formation increases reducing moisture resistance
Solution Approach 1:
The invention introduces curved coupling surfaces with specific radii of curvature (R1 for the first coupling surface and R2 for the second coupling surface) to replace the right angle step portion. This curvature design maintains clear structural definition while eliminating the sharp corner that causes air bubble entrapment. The curved transition ensures that materials flow smoothly during the sintering process, preventing void formation and improving moisture resistance without significantly complicating the overall structure.
3Ease of manufacture
If the inner layer portion protrudes beyond the outer layer portion, then terminal electrode formation is improved, but air bubbles form at the boundary reducing moisture resistance
Solution Approach 1:
The invention employs curved coupling surfaces with radii R1 and R2 at the boundaries where the inner layer portion protrudes beyond the outer layer portion. This curved transition eliminates the sharp corner that would otherwise cause air bubbles to form during sintering. The smooth curvature allows materials to flow uniformly, preventing air bubble entrapment while still maintaining the protrusion necessary for proper terminal electrode formation and connection.
Data Source
AI summary
A multilayer ceramic electronic component includes a multilayer body, first and second external electrodes on first and second end surfaces. The multilayer body includes an inner layer portion, and first and second outer layer portions. The first and second end surfaces each include an inner layer and first and second outer layer end surfaces. The inner layer end surface includes a protruding end surface, a first coupling surface connecting the first outer layer end surface and the protruding end surface, and a second coupling surface connecting the second outer layer end surface and the protruding end surface. Angles between the first and second outer layer end surfaces and between the first and second coupling surfaces at a boundary between the first and second outer layer end surfaces and the first and second coupling surfaces, are obtuse angles.