Multilayer Ceramic Component Resin Mold Creepage Distance
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Solution Overview
Problem
Multilayer ceramic electronic components with metal terminals face issues with stress due to thermal expansion differences, leading to potential cracking and reduced reliability when connected in series, and challenges in accurately measuring insulation resistance values (IR) within the component.
Innovation Solution
A multilayer ceramic electronic component design featuring a first and second multilayer ceramic electronic component body connected through metal terminals, with an outer casing covering the components and exposed third metal terminal for accurate IR measurement, allowing for reliable identification and removal of defective components with low IR values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If two or more multilayer ceramic capacitors are connected in series to achieve higher breakdown voltage and larger capacity, then the breakdown voltage between metal terminals is raised, but the short distance between terminals causes creeping discharge that reduces breakdown voltage
Solution Approach 1:
A resin mold is introduced as an intermediary material between the metal terminals and the multilayer ceramic capacitors. This resin mold increases the creepage distance by providing an insulating path that prevents direct discharge through air, thereby maintaining higher breakdown voltage while allowing series connection of multiple capacitors.
Solution Approach 2:
The resin mold acts as a flexible insulating shell that encapsulates the metal terminals and capacitors. This shell structure provides both electrical insulation to prevent creeping discharge and mechanical protection, while allowing the compact series connection configuration to be maintained.
2Reliability
If the multilayer ceramic electronic component is molded by resin to increase creepage distance, then breakdown voltage is maintained, but characteristics selection becomes difficult as individual IR values cannot be measured
Solution Approach 1:
Measurement terminals are provided that extend from the interior of the resin mold to the exterior surface, allowing IR value measurements to be performed before final product assembly. This preliminary measurement capability enables quality control while maintaining the benefits of resin molding for creepage distance.
Solution Approach 2:
The measurement terminals act as intermediaries that bridge the interior measurement points (where IR values need to be measured) and the exterior measurement equipment. These terminals penetrate the resin mold to provide electrical access without compromising the insulating properties of the resin for creepage distance.
3Reliability
If metal terminals are used to connect multilayer ceramic capacitors, then thermal shock resistance is improved through elastic deformation, but stress from thermal expansion differences causes cracking and reduced reliability
Solution Approach 1:
The resin mold provides a flexible encapsulation that absorbs and distributes thermal expansion stresses. This flexible shell structure prevents stress concentration at the metal terminal-to-capacitor interfaces, reducing the likelihood of cracking while maintaining the thermal shock resistance benefits of metal terminals.
Solution Approach 2:
The combination of metal terminals, multilayer ceramic capacitors, and resin mold creates a composite structure that leverages the advantages of each material: metal for thermal shock resistance, ceramic for capacitance, and resin for stress distribution and creepage distance. This composite approach resolves the contradiction between thermal performance and stress resistance.
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 configuration ensures accurate measurement and reliable removal of defective components, maintaining high product quality by ensuring all components have insulation resistance values above the standard limit, thus enhancing the component's reliability and performance.
Implementation Method 1
heat for soldering is transmitted through the metal terminal to an electronic component body. Thus, thermal shock can be less likely to be applied to the electronic component body
Implementation Method 2
a temperature change causes even stress or deformation of the wiring board, which can be advantageously absorbed by elastic deformation of the metal terminal
Implementation Method 3
when a temperature changes, a wiring board and an electronic component body expand or contract based on their respective thermal expansion coefficients
Data Source
AI summary
A multilayer ceramic electronic component includes first and second multilayer ceramic electronic component bodies facing each other in a length direction that connects first and second end surfaces. A first metal terminal is connected to a first outer electrode. A second metal terminal is connected to a fourth outer electrode. An outer casing covers the first and second multilayer ceramic electronic component bodies, and at least a portion of each of the first and second metal terminals. A third metal terminal is exposed from the outer casing.