Chamfered Hanger Leads for Secure LED Package Attachment
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Solution Overview
Problem
Conventional light-emitting device packages face challenges in secure attachment and easy detachment from lead frames, leading to potential falling off during handling and manufacturing processes.
Innovation Solution
A lead frame and package design featuring a depression with a supporting member made of resin, where the hanger leads are chamfered and projections are formed to securely hold the package, allowing for easy detachment by pressing downward without falling off the frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packages are designed without chamfered surfaces on hanger leads, then the structure is simpler, but the packages may accidentally fall off the lead frame during handling
Solution Approach 1:
The patent applies curvature by forming chamfered surfaces on the corner portions of the hanger leads. These chamfered surfaces create a geometric interference feature that prevents the package from detaching accidentally, while maintaining a relatively simple overall structure. The curved/chamfered geometry provides a mechanical lock without requiring complex additional components.
2Reliability
If packages are securely attached to lead frames, then accidental falling is prevented, but detachment during manufacturing becomes difficult
Solution Approach 1:
The patent implements a dynamic attachment system where the chamfered surfaces provide secure holding under normal conditions, but allow controlled detachment when intentional force is applied. The chamfered geometry creates a directional release mechanism that enables easy removal during manufacturing while preventing accidental detachment during handling.
3Reliability
If hanger leads extend far to contact the supporting member, then secure attachment is achieved, but the lead frame occupies more space
Solution Approach 1:
The patent applies local quality by forming chamfered surfaces specifically on the corner portions of the hanger leads where they contact the supporting member. This localized geometric modification provides the necessary attachment security without requiring the hanger leads to extend further, thus maintaining a compact lead frame area while achieving reliable attachment at the critical contact points.
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
A lead frame includes an electrode, a hanger lead, and an outer frame and is formed integrally with a supporting member supporting the electrode, so that a package having a depression in which a light-emitting element will be mounted is formed. The depression is open on the upper side, its side walls are mainly constituted of the supporting member, and at least a part of its bottom surface includes the electrode. The electrode is disposed in a supporting member forming region. The hanger lead extends from the outer frame to reach the supporting member forming region. A chamfered surface is formed on at least a part of an upper side corner of an end of the hanger lead.