Lead Frame Segmentation for Stress Relief in LED Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lead frames used in light-emitting devices often experience residual stress and distortion due to pressing processes, which can lead to manufacturing errors during resin molding and light-emitting element mounting.
Innovation Solution
A lead frame design featuring units with first and second lead portions arranged in specific directions, connected by suspension and connecting portions, which allows stress to be released at the second lead portion, reducing residual stress and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pressing process is applied to the lead frame to reduce dicer blade abrasion during separation, then the cutting process is facilitated, but residual stress accumulates at the pressed portions causing distortion and warping
Solution Approach 1:
The lead frame is divided into multiple units (first units and second units) with distinct structural configurations. The first units have leads connected in both x and y directions, while the second units have leads connected only in the x direction, creating segmented stress distribution zones that prevent overall distortion
Solution Approach 2:
Different portions of the lead frame are given different connection characteristics - some portions have y-direction connections for stability while others have only x-direction connections for stress relief. This local differentiation allows the pressing process to be effective without causing global distortion
2Manufacturing precision
If the lead frame structure is made more rigid to maintain manufacturing precision, then distortion is reduced, but the pressing process becomes more difficult and blade abrasion increases
Solution Approach 1:
The lead frame is segmented into different unit types with varying connection densities. This segmentation creates zones of different rigidity - some areas provide stability while others allow controlled deformation during pressing, facilitating the cutting process without increasing blade abrasion
3Strength
If all lead portions are connected in both x and y directions to maximize structural strength, then the lead frame maintains its shape, but residual stress cannot be released causing warping
Solution Approach 1:
The lead frame combines first units with full x-y connectivity for strength with second units having only x-direction connectivity for stress relief. This segmented approach allows the structure to maintain overall integrity while providing localized stress release pathways that prevent warping
Solution Approach 2:
Different regions of the lead frame have different connection characteristics - some regions have bidirectional connections for strength while others have unidirectional connections for stress release. This local quality differentiation enables simultaneous achievement of structural integrity and warping prevention
Data Source
AI summary
A lead frame includes: a plurality of units each including a first lead portion and a second lead portion arranged in a first direction, wherein the units are arranged in the first direction and in a second direction perpendicular to the first direction, and the first lead portion and the second lead portion of each unit are adjacent, in the second direction, to the first lead portion and the second lead portion of an adjacent one of the units that is adjacent in the second direction; a plurality of first suspension portions; and a plurality of connecting portions. Each of the first suspension portions connects, in the second direction, the first lead portions of units that are adjacent to each other in the second direction.