LED Package Lead-Frame Segmentation for Mounting
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Solution Overview
Problem
Existing light emitting device packages face issues with surface mounting characteristics and light extraction efficiency due to distorted lead-plate shapes, leading to suboptimal bonding wire lengths and uneven adhesive application.
Innovation Solution
A light emitting device package design featuring lead-frames with extensions and recesses, where the molded resin separates exposed regions, allowing for shorter bonding wires and improved symmetry and uniformity of exposed surfaces, enhancing surface mounting and thermal dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lead-plates are used with exposed regions for mounting, then surface mounting can be achieved, but distorted shapes of lead-plates degrade surface mounting characteristics
Solution Approach 1:
The lead-frame is divided into a main body and an extension part. The extension part includes a first exposed region that is separated from the second exposed region of the main body by molded resin. This segmentation allows each part to have optimized characteristics for its specific function.
Solution Approach 2:
The extension part is extracted from the main body and given a specific shape with narrowed width. This extracted part serves as a dedicated mounting region with improved shape uniformity, separate from the main body of the lead-frame.
2Productivity
If lead-frames are extended towards each other to reduce bonding wire length, then light extraction efficiency improves, but shape distortion increases
Solution Approach 1:
Different parts of the lead-frame have different properties: the main body maintains structural integrity while the extension part is designed with narrowed width and specific shape for optimal mounting. This local differentiation allows the extension to achieve short bonding wire length without causing overall distortion.
Solution Approach 2:
The extension part has an asymmetric shape with narrowed width compared to the main body. This asymmetric design allows the extension to extend towards the other lead-frame for short bonding wires while the main body maintains its structural stability.
3Ease of manufacture
If exposed regions of lead-frames are made large for better adhesive application, then surface mounting improves, but bonding wire length increases
Solution Approach 1:
The exposed regions are segmented into two separate parts: the second exposed region on the main body and the first exposed region on the extension part. This segmentation allows the first exposed region to be optimally positioned for short bonding wires while the second exposed region provides adequate area for adhesive application.
Data Source
AI summary
The light emitting device package of the present invention has a longitudinal direction (as viewed from above) and a transverse direction perpendicular to the longitudinal direction, and is provided with a first and second lead-frame lined-up in the longitudinal direction and molded resin holds the first and second lead-frames integrally. The package is characterized in that the first lead-frame has a main body and an extension that extends from the main body with a narrowed width towards the second lead-frame. Further, a recess is established in the bottom surface of the first lead-frame, and at least part of the exposed region of the bottom surface of the extension is separated from the exposed region of the bottom surface of the main body by the molded resin that fills the recess.