Multilayer Ceramic Capacitor Asymmetric Electrode Design
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Solution Overview
Problem
The challenge lies in forming and positioning external electrodes on the height-direction surfaces of multilayer ceramic capacitors, particularly when the capacitor dimensions are small, where deviations from ideal positions and shapes lead to defective samples in appearance inspections, resulting in reduced yield and increased costs.
Innovation Solution
A multilayer ceramic capacitor design with a capacitor body of roughly rectangular shape, featuring a tapered part on one height-direction surface with a concaved center, allowing the external electrodes to cover lead parts and project slightly outward, thereby improving inspection outcomes and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If external electrodes are formed on one height-direction surface to maximize capacitance, then capacitance increases, but manufacturing precision deteriorates due to positioning deviations
Solution Approach 1:
The capacitor body is designed with asymmetric dimensions where the width in the width direction (W1) is greater than the width in the length direction (L1). This asymmetry creates a geometric buffer that accommodates electrode positioning deviations, allowing electrodes to be formed on one height-direction surface while maintaining manufacturing feasibility and preventing defects even when positioning varies within tolerance ranges.
2Volume of moving object
If capacitor external dimensions are reduced to minimize size, then miniaturization is achieved, but manufacturing precision worsens due to higher frequency of positioning deviations
Solution Approach 1:
By designing the capacitor body with asymmetric dimensions (W1 > L1), the invention creates a geometric configuration where the larger width dimension provides sufficient margin for electrode formation. This allows miniaturization of the capacitor while maintaining adequate positioning tolerance, as the asymmetric geometry ensures that even with positioning deviations, electrodes will not extend beyond the capacitor body boundaries.
3Reliability
If external electrodes are designed to cover lead parts completely, then appearance quality improves, but manufacturing flexibility decreases due to stricter inspection criteria
Solution Approach 1:
The asymmetric dimensioning (W1 > L1) creates a geometric buffer zone that accommodates normal variations in electrode formation. This allows the electrode design to cover lead parts adequately for appearance quality while tolerating reasonable positioning deviations, thereby maintaining manufacturing flexibility without requiring extremely tight process control.
Data Source
AI summary
In an embodiment, a multilayer ceramic capacitor 10 has the first external electrode 12 and second external electrode 13 provided with a space between them on the other height-direction surface f6 of the capacitor body 11 in the length direction, where the width Wa of the other height-direction surface f6 of the capacitor body 11 is smaller than the width W of the one height-direction surface f5. The multilayer ceramic capacitor can improve yield and help reduce cost by allowing several of the conditions to be found non-defective in the appearance inspection.