Embedded LED Package Electrodes Prevent SMT Solder Overflow
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Solution Overview
Problem
Conventional LED packages face issues during the surface mounting technology (SMT) process due to the close proximity of electrodes, leading to solder overflow and potential short circuits, which contaminates electrodes and affects reliability.
Innovation Solution
The LED package design features a substrate with electrodes spaced apart, including a connecting bar and a reflector that surrounds the LED chips, preventing solder overflow by maintaining electrode separation and enhancing manufacturing efficiency through a method involving a lead frame and molding of insulating material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If electrodes are arranged close together on the substrate, then the device size is reduced, but solder overflow occurs during SMT process causing short circuits
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement of electrodes on the substrate surface to a three-dimensional configuration where electrodes are embedded within the substrate. This vertical embedding creates additional spatial separation between adjacent electrodes, effectively increasing the insulation distance without increasing the horizontal device footprint, thus preventing solder overflow while maintaining compact size.
Solution Approach 2:
The patent introduces an insulating material as an intermediary substance that fills the spaces between embedded electrodes within the substrate. This insulating material acts as a barrier that prevents electrical contamination and solder overflow between adjacent electrodes, ensuring reliable electrical isolation while allowing the electrodes to be positioned in a compact arrangement.
2Reliability
If electrodes are spaced apart to prevent solder overflow, then reliability is improved, but the device area increases
Solution Approach 1:
The patent utilizes the third dimension (depth) by embedding electrodes within the substrate rather than arranging them only on the surface. This vertical positioning allows for adequate electrical isolation between electrodes through the substrate thickness and insulating material, achieving reliable electrode separation without requiring increased horizontal spacing, thus maintaining a compact device footprint.
Solution Approach 2:
The patent employs a composite structure consisting of the substrate material combined with embedded electrodes and insulating material. This composite construction integrates multiple functions: the substrate provides mechanical support and electrical insulation, the electrodes provide electrical connections, and the insulating material ensures isolation between adjacent electrodes. This composite approach achieves both compact size and high reliability.
3Ease of manufacture
If conventional LED package structure is used, then manufacturing process is simple, but solder contamination causes short circuits
Solution Approach 1:
The patent implements preliminary action by pre-arranging the electrodes within the substrate structure before the SMT process. The electrodes are embedded and positioned in advance with adequate spacing and insulation, so that during the subsequent soldering process, solder overflow cannot cause short circuits. This preliminary structural arrangement prevents the short circuit problem without complicating the manufacturing process.
Data Source
AI summary
An exemplary light-emitting diode (LED) package includes an electrically insulating substrate, an electrode structure embedded in the insulating substrate, and a plurality of LED chips electrically connecting with electrodes of the electrode structure respectively. The electrode structure includes a first electrode, a second electrode and a third electrode located between the first and second electrodes. Top surfaces of the first, second and third electrodes are exposed out of a top surface of the insulating substrate to support the LED chips. Front side and rear side faces of the first and second electrodes are exposed out of a front side face and a rear side face of the substrate whereby the front or rear side faces of the first and second electrodes can connect with welding pads of a printed circuit board. Circumferential side faces of the third electrode are encapsulated in the substrate.