LED Mount Lead Terminal Recess Structure for Resin Sealing
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Solution Overview
Problem
Existing light emitting device mounts face issues with sealing resin material leakage and solder flux entry due to gaps between the leadframe and external resin portion, leading to potential structural weaknesses and contamination.
Innovation Solution
A light emitting device mount design featuring positive and negative lead terminals with recessed surface areas and extension parts, integrated with a resin portion that covers the end surfaces, enhancing the surface area and adhesive strength while preventing resin leakage and flux entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the leadframe and external resin portion are joined with a small gap, then the manufacturing process is simplified, but sealing resin material leaks to the bottom surface and solder flux enters the recessed part
Solution Approach 1:
The end surface of the lead terminal is designed with a recessed surface area that creates a localized sealing structure. This recessed area forms a barrier that prevents sealing resin material from leaking to the bottom surface and blocks solder flux from entering the recessed part, while maintaining the overall simplicity of the manufacturing process.
Solution Approach 2:
The recessed surface area is formed on the end surface of the lead terminal before the final assembly. This preliminary structural preparation ensures that when the resin portion is attached, the sealing function is automatically provided by the pre-formed recessed structure, preventing leakage and flux entry without requiring additional sealing steps.
2Device complexity
If the end surface of the lead terminal is flat, then the structure is simple, but the adhesive strength between the resin portion and lead terminal is insufficient
Solution Approach 1:
Instead of making the entire end surface complex, only a specific area (the recessed surface area) is modified with a recessed structure. This localized modification increases the surface area for adhesion between the resin portion and lead terminal, enhancing bonding strength while keeping the overall structure relatively simple.
3Weight of moving object
If the peripheral edge parts of the leadframe are made thin, then the weight is reduced, but the strength of the peripheral edge parts decreases
Solution Approach 1:
The recessed surface area is strategically positioned on the end surface to provide localized structural reinforcement. This recessed structure creates a barrier that prevents resin leakage and flux entry, thereby protecting the peripheral edge areas from harmful substances that could weaken them, allowing the leadframe to maintain lower weight while preserving peripheral strength through the protective barrier function.
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3B
AI summary
A light emitting device mount comprising a pair of lead terminals (10, 11), each including a first main surface (10a), a second main surface (10b) that is located on the opposite side to said first main surface (10a), and an end surface having first and second recessed surface areas (10ca, 10cb) that include curved surfaces and extend from said first and second main surfaces (10a, 10b), respectively, as viewed in cross-section, the end surface also having a middle area (10cc) between said first and second recessed surface areas (10ca, 10cb); and a resin portion (20) that is integrally formed with said pair of lead terminals (10, 11), and covers said end surface so that said second main surface (10b) is at least partially exposed, wherein the area of said second recessed surface area (10cb) is larger than that of said first recessed surface area (10ca).