ESD Protection Device Using Glass-Coated Metallic Particles
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Solution Overview
Problem
Conventional ESD protection devices have limitations in lowering discharge starting voltage and peak voltage, and suffer from performance degradation due to the use of resin, which lacks sufficient heat resistance and oxidation resistance, leading to characteristic degradation when static electricity is repeatedly applied.
Innovation Solution
An ESD protection device featuring a ceramic base material with opposed electrodes and a discharge auxiliary electrode film made of metallic particles coated with glass, along with an inorganic oxide and semiconductor powder, which increases the metallic particle content and enhances heat resistance, reducing discharge starting and peak voltages while preventing characteristic degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resin is used to isolate metallic particles in the static electricity protective material layer, then the metallic particles are isolated from each other, but the resin degrades due to insufficient heat resistance and oxidation resistance, causing performance degradation when static electricity is applied repeatedly
Solution Approach 1:
The patent removes the resin component from the static electricity protective material layer, extracting the harmful element that caused degradation. The material layer consists only of metallic particles without any resin binder, eliminating the heat resistance and oxidation resistance problems associated with organic resins while maintaining particle isolation through a different mechanism.
Solution Approach 2:
The patent replaces the degradable resin with a simple, stable structure where metallic particles are directly arranged without organic binders. This approach uses durable inorganic materials that can withstand repeated electrostatic discharge events without degradation, sacrificing the ease of particle isolation provided by resin for long-term reliability.
2Ease of manufacture
If resin is used as the binding material in the static electricity protective material layer, then the metallic particles can be kneaded and formed into a layer, but the resin lacks sufficient heat resistance and oxidation resistance, leading to characteristic degradation
Solution Approach 1:
The patent extracts the resin component from the material composition, creating a layer of metallic particles without organic binders. This eliminates the contradiction by removing the material that enabled easy formation but caused reliability problems under thermal and oxidative stress.
3Reliability
If the ratio of metallic particles in the static electricity protective material layer is limited, then the resin can effectively isolate the particles, but the ability to lower discharge starting voltage and peak voltage is limited
Solution Approach 1:
By removing the resin component entirely, the patent enables a higher concentration of metallic particles in the protective material layer. This increases the quantity of conductive particles available for electrostatic discharge, thereby improving the ability to lower discharge starting voltage and peak voltage without being constrained by resin content limitations.
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 lowers discharge starting and peak voltages and maintains stable performance over time by using glass-coated metallic particles and inorganic oxides, preventing degradation and improving reliability in ESD protection.
Implementation Method 1
metallic particles with glass covering the metallic particles
Implementation Method 2
the resin used for isolating the metallic particles from each other essentially does not have necessarily sufficient heat resistance and oxidation resistance
Implementation Method 3
a discharge auxiliary electrode film arranged to connect the pair of opposed electrodes, wherein the discharge auxiliary electrode film contains, as its main constituents, metallic particles and glass covering the metallic particles
Data Source
AI summary
An ESD protection device includes a ceramic base material, a pair of opposed electrodes provided on a surface of or in the ceramic base material, and a discharge auxiliary electrode film arranged to connect the pair of opposed electrodes, wherein the discharge auxiliary electrode film is composed of a material containing, as its main constituents, metallic particles and glass covering the metallic particles. The discharge auxiliary electrode film is formed by providing an electrode paste containing glass-coated metallic particles that have an approximately 15% rate of increase in weight at about 400° C. for about 2 hours in air, a resin binder, and a solvent so as to connect the pair of opposed electrodes to each other, and then firing at a temperature of about 600° C. or more, higher than a softening point of glass of the glass-coated metallic particles, and not +200° C. higher than the softening point.