ESD Protection Device Using Core-Shell Metal Particles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ESD protection devices face issues with insulation reliability and peak voltage reduction due to exposed conductive metal particles and incomplete coverage of inorganic coatings, leading to potential short-circuiting and reduced discharge efficiency.
Innovation Solution
The use of core-shell metal particles with a metal oxide shell, where the core is primarily copper and the shell is a more easily oxidized metal oxide, such as aluminum oxide, provides complete coverage and enhances insulation reliability, reducing peak voltage and preventing short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If metal-based conductive powder is used in the auxiliary electrode, then discharge speed is improved, but insulation reliability deteriorates due to exposed conductive particles
Solution Approach 1:
The patent applies a thin film coating of metal oxide (such as aluminum oxide) on the surface of conductive metal particles. This thin film acts as an insulating shell that prevents direct electrical contact between adjacent conductive particles while maintaining the discharge functionality. The coating thickness is controlled to be sufficient for insulation but thin enough to allow electrical field penetration for discharge acceleration.
Solution Approach 2:
The patent creates a composite particle structure combining conductive metal core (for discharge functionality) with insulating metal oxide shell (for insulation reliability). This composite structure allows the auxiliary electrode to simultaneously achieve fast discharge speed through the conductive core and high insulation reliability through the insulating shell, resolving the contradiction between these two opposing requirements.
2Reliability
If inorganic material coating is applied to conductive material, then insulation reliability is improved, but complete surface coverage is difficult to achieve
Solution Approach 1:
The patent performs surface preparation of the metal particles before coating, including roughening or activating the surface to enhance adhesion of the metal oxide coating. This preliminary action ensures that the coating bonds strongly and uniformly to the particle surface, preventing delamination and achieving complete coverage.
Solution Approach 2:
The patent optimizes coating parameters such as coating thickness, material composition, and application method to achieve uniform and complete surface coverage. By carefully controlling these parameters, the patent ensures that the insulating metal oxide layer completely covers the conductive particle surface without gaps or thin spots, achieving both high insulation reliability and complete manufacturing precision.
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 core-shell structure ensures high insulation reliability and efficient discharge characteristics by completely covering metal particles with a metal oxide shell, maintaining performance even under repeated electrostatic discharge and drop impacts.
Implementation Method 1
a shell portion mainly composed of at least one metal oxide that contains a second metal
Implementation Method 2
an auxiliary electrode for accelerated discharge astride between the first and second discharge electrodes
Data Source
AI summary
An ESD protection device providing highly reliable insulation and having good discharge characteristics is provided. An ESD protection device has opposing first and second discharge electrodes, an auxiliary discharge electrode (18) astride between the first and second discharge electrodes, and an insulating substrate (12) supporting the first and second discharge electrodes and the auxiliary discharge electrode (18). The auxiliary discharge electrode (18) is composed of an assembly of core-shell metal particles (24) that have a core portion (22) mainly composed of a first metal and a shell portion (23) mainly composed of a metal oxide that contains a second metal. The metal particles (24) are substantially completely covered with the shell portion (23) mainly composed of the metal oxide, and this improves the insulation reliability of the device against discharge. Preferably, the metal particles (24) have a bond with each other with a vitreous substance (27) therebetween.