Laminated Ceramic Capacitor Plating Films at Rounded Corners
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Solution Overview
Problem
Laminated ceramic capacitors face challenges in reducing size and increasing capacitance while maintaining humidity resistance and minimizing thickness, as existing methods for forming external terminal electrodes can lead to short circuits and inadequate humidity resistance.
Innovation Solution
The solution involves forming external terminal electrodes with plating films that stop at rounded corners of the ceramic element assembly, using auxiliary conductor films with a glass component to extend to principal surfaces, and incorporating dummy internal conductors to enhance fixing force and control precipitation areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the ceramic layer is reduced to increase capacitance and reduce size, then the capacitance increases and size decreases, but short circuiting between internal electrodes occurs and quality becomes difficult to secure
Solution Approach 1:
The patent uses a thin plating film (external terminal electrode) with controlled thickness and composition to provide protective coverage over the ceramic element assembly. This thin film approach allows the ceramic layers to be made thinner for increased capacitance while the plating film maintains reliability by preventing short circuits between internal electrodes.
2Area of stationary object
If the area of the ceramic layer is increased to increase the effective area of internal electrodes, then the effective area increases, but the thickness of the external terminal electrode increases and the area of the ceramic layer is reduced
Solution Approach 1:
The patent changes the parameters of the external terminal electrode by controlling the plating film thickness to be 3 μm or less and adjusting the composition (Cu content: 60-80 at%, Ni content: 10-30 at%, Pd content: 1-10 at%). These parameter changes allow the electrode to be thin enough not to reduce the ceramic layer area while still providing sufficient coverage and functionality.
3Ease of manufacture
If conductive paste is applied by immersion to form external terminal electrodes, then the electrodes are formed, but the paste thickly adheres to the center of end surfaces and the electrodes are partially thickened, reducing the ceramic layer area
Solution Approach 1:
The patent replaces the mechanical immersion paste application method with a plating process. This substitution allows for precise control of electrode thickness and uniform distribution, preventing the thick adhesion problem that occurs with paste immersion while maintaining ease of manufacture through established plating techniques.
4Reliability
If plating films are formed to extend up to one portion of each of a pair of adjacent principal surfaces from the end surfaces, then the external terminal electrodes are formed, but the height dimension increases
Solution Approach 1:
The patent uses a thin plating film that extends to but does not protrude from the principal surface of the ceramic element assembly. This thin film configuration provides adequate humidity resistance reliability by covering the end surfaces and reaching the principal surfaces, while the controlled thickness prevents excessive height 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
This approach increases humidity resistance reliability, allows for thinner capacitors, and minimizes height dimension increase, effectively addressing the limitations of previous methods.
Implementation Method 1
a method for directly forming external terminal electrodes by plating has been proposed
Implementation Method 2
the glass component partially penetrates in the interfaces of the plating films and the ceramic element assembly
Data Source
AI summary
In a laminated ceramic electronic component, external terminal electrodes include plating films directly covering exposed portions of internal electrodes on end surfaces of a ceramic element assembly. On the boundaries between the end surfaces and principal surfaces of the ceramic element assembly, substantially rounded corners are provided, and the plating films are arranged such that the ends of the plating films stop at the corners and do not project from the principal surfaces.