Chip Fuse Bank Section Design for Arc Containment
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Solution Overview
Problem
Conventional chip fuses face challenges in improving interruption performance, including retention of appearance and reduction of sustained arc, due to damage and scattering of protective layers during the melting of the fuse element section.
Innovation Solution
A chip fuse design featuring a rectangular bank section on the heat-storing layer and surface electrode sections to surround the fuse element section, with a protective layer formed on the inner side of the bank section, using a photosensitive-group-containing material for the bank and heat-storing layer, and an epoxy-group-containing silicone-based resin for the protective layer, which is soft and elastic to absorb impact, and an inorganic-filler-containing silicone-based resin for additional strength and friction resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional protective layers are used during fuse element melting, then the protective layers are damaged and scattered, but this leads to poor interruption performance and appearance retention
Solution Approach 1:
A bank section is formed beforehand surrounding the fuse element section to create a protective enclosure. This bank section prevents the protective layer from being scattered during fuse element melting, thereby maintaining protective layer integrity while ensuring reliable interruption performance and appearance retention.
2Loss of substance
If the protective layer is made thinner to reduce material usage, then manufacturing cost decreases, but the protective layer becomes more susceptible to damage during melting
Solution Approach 1:
The bank section is formed beforehand to surround the fuse element section, creating a containment structure that protects the protective layer during melting. This allows the protective layer to be thinner while maintaining reliability, as the bank section prevents scattering and damage regardless of protective layer thickness.
3Strength
If a rigid protective layer structure is used, then structural strength is improved, but the protective layer cannot absorb impact during melting and detaches
Solution Approach 1:
The protective layer is formed from a soft and elastic material that can absorb impact during fuse element melting. This parameter change from rigid to elastic material prevents detachment while maintaining sufficient strength, as the elastic material can deform to absorb melting impact and then return to its original state.
4Reliability
If multiple protective layers are added to prevent damage, then reliability improves, but device complexity increases
Solution Approach 1:
Instead of adding multiple protective layers, a single protective layer is used in combination with a bank section formed beforehand. The bank section provides the necessary protection and containment, allowing a simpler single-layer structure to achieve high reliability without increasing device complexity.
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 design effectively prevents damage to the protective layers during the melting process, ensuring a sufficient thickness and adhesion, reducing the likelihood of detachment and improving the chip fuse's interruption performance by retaining appearance and minimizing sustained arcs.
Implementation Method 1
exposing the sheet-shaped photosensitive-group-containing material to ultraviolet light for development (photo-etching) to thereby form the rectangular bank section
Implementation Method 2
an epoxy-group-containing silicone-based resin for the protective layer, which is soft and elastic to absorb impact
Implementation Method 3
interposing the heat-storing layer 3 between the insulated substrate 2 and the fuse film 4 prevents the fuse film 4 from coming into contact with the insulated substrate 2. Hence, when a current passes through the chip fuse 1, heat generated at a fuse element section 4b is stored in the heat-storing layer 3 without dissipating to the insulated substrate 2
Data Source
AI summary
In a chip fuse, a heat-storing layer is formed on an insulated substrate, a fuse film is formed on the heat-storing layer, and a protective film is formed on the fuse element section. The chip fuse includes surface electrode sections on both ends in the length direction of the chip fuse and a fuse element section between the surface electrode sections. In this chip fuse, a rectangular bank section is formed over the heat-storing layer and the surface electrode sections to surround the fuse element section, and a first protective layer is formed on the inner side of the bank section. In addition, during the bank formation process, a sheet-like photosensitive-group-containing material is laminated on the fuse element section, surface electrode sections, and heat-storing layer, and the sheet-like photosensitive-group-containing material is exposed to ultraviolet light and developed to form the rectangular bank section.