Lead Frame Segmentation for Accurate LED Singulation
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Solution Overview
Problem
The existing manufacturing processes for light emitting devices face defects due to varying stress on cutting blades caused by the shape of the lead frame, leading to positional deviations and inaccurate cutting during singulation.
Innovation Solution
A lead frame design featuring unit structures with alternating first and second lead portions, extending portions, and coupling portions, where at least one extending portion at the end is not directly connected to the outer frame, allowing for gradual transition of cutting stress and reducing positional deviation of the cutting blade.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lead frame uses a conventional shape with extending portions connecting adjacent light emitting devices, then the structural integrity of the lead frame is maintained, but the cutting blade experiences varying stress causing positional deviation and cutting defects
Solution Approach 1:
The lead frame is divided into multiple unit structures (first and second groups) with coupling portions connecting them. The extending portions are strategically designed to connect lead portions between groups while leaving at least one end extending portion disconnected from the outer frame, creating segmented stress distribution that prevents blade deviation during cutting
Solution Approach 2:
Different regions of the lead frame are designed with different connectivity characteristics. The coupling portions connect extending portions to maintain structural integrity, while the end extending portions are deliberately left disconnected from the outer frame to create low-stress zones that prevent cutting blade deviation during singulation
2Manufacturing precision
If the lead frame structure is modified to prevent cutting stress variation, then cutting precision is improved, but the lead frame design complexity increases
Solution Approach 1:
The lead frame is segmented into unit structures with clear functional zones: coupling portions for structural connection and end extending portions for stress relief. This segmentation provides a systematic approach to managing cutting stress while maintaining design clarity and ease of manufacturing
Solution Approach 2:
Instead of connecting all extending portions to the outer frame to maximize structural integrity, the invention inverts the approach by deliberately leaving end extending portions disconnected. This counterintuitive design reduces cutting stress variation and improves cutting precision without significantly increasing complexity
Data Source
AI summary
A lead frame includes a plurality of unit structures, an outer frame, a plurality of extending portions, and a plurality of coupling portions. The unit structures each includes a first lead portion and a second lead portion aligned in a first direction, and grouped into first and second groups including a plurality of the unit structures aligned in the first direction. The extending portions each includes a first extending portion extending in the second direction and connecting the first lead portions of the unit structures in the first and second groups a second extending portion connecting the second lead portions of the unit structures in the first and second groups. The coupling portions connect all the first extending portions and the second extending portions. At least one of the extending portions located at one of ends in the first direction is not directly connected to the outer frame.