LED Lead Frame Standing Parts for Stronger Resin Bonding
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Solution Overview
Problem
Existing semiconductor light emitting devices face challenges in achieving high adhesion between the resin molding and the lead frame, leading to potential separation and disconnection issues.
Innovation Solution
The semiconductor light emitting device incorporates standing parts on the lead frame that extend above the surface and are embedded in the resin frame, increasing the contact area and enhancing adhesion between the resin and metal lead frame, while also improving mechanical strength through a symmetrical and orthogonal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resin molding is filled in the cutouts of the lead frame to enhance adhesion, then the adhesion between resin and lead frame is improved, but the contact area is restricted to the thickness of the lead frame
Solution Approach 1:
The invention transitions from a two-dimensional contact interface (flat surface of lead frame) to a three-dimensional contact structure by adding standing parts that extend vertically. The standing parts create multiple contact surfaces (top surface and side surfaces) that are embedded in the resin, effectively increasing the contact area from a single plane to a multi-faceted volume-based interface.
Solution Approach 2:
The lead frame is segmented into multiple functional parts: the base lead frame structure and the protruding standing parts. This segmentation allows the standing parts to specifically engage with the resin molding while the rest of the lead frame maintains its electrical and structural functions, creating specialized contact zones for enhanced adhesion.
2Reliability
If the contact area between resin and lead frame is increased, then adhesion is enhanced, but the structural complexity increases
Solution Approach 1:
Rather than expanding the contact area horizontally which would increase the overall device footprint and complexity, the invention adds vertical dimension through standing parts. This approach increases adhesion area without proportionally increasing structural complexity, as the standing parts are integrated into the existing lead frame geometry.
3Reliability
If the adhesion between resin molding and lead frame is improved, then separation is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The standing parts are formed on the lead frame before the resin molding process. This preliminary structuring allows the resin to be molded around pre-positioned features, ensuring proper alignment and contact area without requiring additional post-assembly steps or complex molding techniques. The standing parts serve as built-in anchors that guide the resin flow and ensure complete embedding.
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
A semiconductor light emitting device 10 includes: a resin frame 11 having an opening 20; a lead frame 12 having leads 12a and 12b exposed in the opening 20; and an LED 28 placed in the opening 20 and connected to the leads 12a and 12b. Standing parts 18a are erected on an upper surface 23a of the lead 12a. The standing parts 18a are embedded in the resin of the frame 11.