Symmetrical Two-Pin LED Lead Frame for Uniform Light Emission
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Solution Overview
Problem
Traditional two-pin LED packages have asymmetrical lead frames, leading to uneven light emission profiles and far-field patterns, which can result in reduced performance and increased failure points due to wire bonds.
Innovation Solution
A symmetrical lead frame structure for a two-pin LED package is introduced, featuring split cup portions on each lead that form a cup when adjacent, allowing an LED flip-chip to be placed across the gap, providing even light emission and improved thermal dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional asymmetrical lead frames are used in two-pin LED packages, then manufacturing is simpler, but light emission profile uniformity deteriorates
Solution Approach 1:
The patent applies asymmetry in reverse by creating a symmetrical lead frame structure where both leads have identical cup portions with the same dimensions and configuration. This symmetry ensures that light emitted from the LED chip is distributed uniformly in all directions, eliminating the uneven light emission profiles caused by traditional asymmetrical designs while maintaining manufacturing simplicity through standardized components.
2Reliability
If wire bonds are used to connect LED chip to leads, then electrical connection is achieved, but reliability deteriorates due to increased failure points
Solution Approach 1:
The patent merges the electrical connection function into the lead frame structure itself by integrating cup portions directly onto the leads. The LED chip is mounted directly onto these cup portions, creating direct electrical contact between the chip and leads without requiring separate wire bonds. This eliminates additional failure points while maintaining electrical connectivity.
3Temperature
If asymmetrical lead frame structure is used, then device complexity is reduced, but thermal management deteriorates
Solution Approach 1:
The patent employs symmetrical design where both leads feature identical cup portions with matching geometries and thermal pathways. This symmetry ensures balanced heat distribution and dissipation from the LED chip through both leads, preventing thermal hotspots and improving overall thermal management efficiency while maintaining structural simplicity.
Data Source
AI summary
Solid-state lighting devices, and more particularly, symmetrical lead frame structures for two-pin light emitting diode (LED) packages and methods for making the same are disclosed. The symmetrical lead frame structure can include a pair of leads that include symmetrical split cup portions that collectively, when placed next to each other, form a cup, across which an LED flip-chip can be placed. Each of the leads can be a respective electrode powering the LED flip-chip, which together with the symmetrical structure, provides a more even light emission profile and far-field pattern. A molded lens can be formed around the lead frame to protect the chip, as well as maintain a gap between the pair of leads of the lead frame structure. In some embodiments, a fill material can be added in the gap between the pair of leads.