LED Device Metallic Frame Segmentation for Vapor Intrusion
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Solution Overview
Problem
The existing LED package structures using QFN technology face issues with shearing force, metal burr, peeling-off, and vapor intrusion during the singulation process, which affect the lighting efficiency and reliability of the LED devices.
Innovation Solution
The implementation of an etching process to create interlocking-type lead frames and blind holes enhances the combination strength between the metallic frame and the packaging body, and a multi-segmented metallic frame structure is used to prevent vapor intrusion, thereby improving the manufacturing process and product reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If QFN technology is used to reduce LED package size, then the bottom surface of metallic frames is exposed for better heat dissipation, but the exposed area becomes vulnerable to vapor intrusion
Solution Approach 1:
The metallic frame is divided into multiple segments with insulated regions between lead frames. This segmentation creates barriers that prevent vapor from intruding into the chip mounting region while maintaining the exposed bottom surface for heat dissipation.
Solution Approach 2:
Insulated regions are introduced as intermediary elements between the lead frames. These insulated regions act as mediators that block vapor intrusion paths while allowing the metallic frame to maintain its heat dissipation function through the exposed bottom surface.
2Ease of manufacture
If conventional metallic frame structure is used, then manufacturing is simpler, but peeling-off occurs during singulation process due to shearing force
Solution Approach 1:
The metallic frame is segmented into multiple sections with insulated regions between lead frames. This segmentation creates interlocking structures that resist shearing forces during singulation, preventing peeling-off while maintaining manufacturing feasibility through etching processes.
Solution Approach 2:
The metallic frame combines conductive metal regions with insulated regions to create a composite structure. This composite design provides both mechanical strength to resist peeling during singulation and electrical insulation where needed, while maintaining relatively simple manufacturing through etching.
3Reliability
If multi-segmented metallic frame structure is implemented, then vapor intrusion is prevented and combination strength is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical assembly processes with an etching process to create the multi-segmented structure. The insulated regions and interlocking features are formed through chemical etching of the metallic frame, eliminating the need for separate mechanical assembly steps and reducing overall manufacturing complexity despite the increased structural detail.
Data Source
AI summary
The present invention relates to an LED device, which includes a metallic frame, an LED chip, and a packaging body. The metallic frame includes a first lead frame and a second lead frame. The first lead frame has a protruding portion extending toward the second lead frame, while the second lead frame has a notch formed correspondingly to the protruding portion. An electrically insulated region is cooperatively defined by the first and second lead frames. The metallic frame defines at least one blind hole in proximate to the electrically insulated region. The LED chip is electrically connected to the first and second lead frames. The packaging body has a base portion encapsulating the metallic frame and a light-permitting portion arranged above the LED chip.