Multilayer Capacitor Internal Electrode Lead Portion Design
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Solution Overview
Problem
Existing multilayer capacitors, such as those described in Japanese Patent Application Laid-open No. 9-148174, fail to meet the demand for increased equivalent series resistance (ESR) while maintaining low equivalent series inductance (ESL), particularly in applications like decoupling capacitors for digital electronic equipment where load currents are increasing and operating frequencies are higher.
Innovation Solution
The multilayer capacitor design includes internal electrodes with lead portions extending from main electrode portions to terminal electrodes, forming narrowed current paths that increase ESR while opposing magnetic fields generated by electric currents between electrodes, thereby suppressing ESL. This design also connects inductor components in parallel to further reduce ESL.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead portions extend from end faces to side faces, then ESR increases through narrowed current paths, but current path length increases
Solution Approach 1:
The lead portion is designed with locally different properties (narrower width) compared to the main electrode portion. This localized change in geometry increases resistance at the connection point without requiring the entire current path to be lengthened, thus achieving higher ESR with minimal increase in path length.
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
The solution effectively increases ESR while minimizing the increase in ESL, meeting the demand for higher capacitance and ESR in multilayer capacitors used as decoupling capacitors, especially in high-frequency applications.
Implementation Method 1
a narrowed portion of an electric current path is formed on the electric current path of each internal electrode, so as to increase the ESR
Implementation Method 2
opposing magnetic fields generated by electric currents between electrodes, thereby suppressing ESL
Data Source
AI summary
A first internal electrode includes a main electrode portion whose longer-side direction agrees with a longer-side direction of first and second principal faces, and a lead portion extending from an end of the main electrode portion on the first end face side toward a first side face and connected to a first terminal electrode. A second internal electrode includes a main electrode portion whose longer-side direction agrees with the longer-side direction of the first and second principal faces, and a lead portion extending from an end of the main electrode portion on the first end face side toward a second side face and connected to a second terminal electrode. A third internal electrode includes a main electrode portion whose longer-side direction agrees with the longer-side direction of the first and second principal faces, and a lead portion extending from an end of the main electrode portion on the second end face side toward the first side face and connected to the first terminal electrode. A fourth internal electrode includes a main electrode portion whose longer-side direction agrees with the longer-side direction of the first and second principal faces, and a lead portion extending from an end of the main electrode portion on the second end face side toward the second side face and connected to the second terminal electrode.