LED Lead Frame Fixing Spaces to Prevent Molding Separation
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Solution Overview
Problem
The existing light emitting devices with a molding unit formed only on the top surface of a lead frame face issues with the widening of the boundary surface between the lead frame and the molding unit, leading to separation during reflow processes, which can expose the light emitting diode and wires to air or moisture, causing damage.
Innovation Solution
The solution involves forming fixing spaces through the lead frame in a vertical direction and integrally forming the molding unit on the top surface of the lead frame and within these fixing spaces, using stepped portions or inclined surfaces to enhance the adhesive force between the molding unit and the lead frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional lead frame with a single large fixing space is used, then the structure is simple and easy to manufacture, but the light emitting diode chip is vulnerable to external impacts and lacks adequate protection
Solution Approach 1:
The single large fixing space of the conventional lead frame is divided into multiple smaller fixing spaces (first fixing space and second fixing space) that are spaced apart. This segmentation allows the lead frame to hold multiple LED chips separately, providing better protection against external impacts while maintaining structural simplicity. Each chip is isolated in its own fixing space, reducing the risk of damage spreading to other chips.
2Reliability
If multiple LED chips are mounted on a conventional lead frame without separate fixing spaces, then the device complexity is low, but the chips are susceptible to moisture and contaminants
Solution Approach 1:
The molding unit acts as an intermediary protective layer that fills the spaces between the lead frame and the external environment. It penetrates into the fixing spaces to directly cover and protect the LED chips mounted on the lead frame, shielding them from moisture and contaminants while allowing the lead frame structure to remain relatively simple.
3Reliability
If LED chips are exposed on the lead frame surface, then the manufacturing process is simple and quick, but the chips are damaged by external impacts
Solution Approach 1:
The molding unit is integrally formed to simultaneously cover multiple lead frame units and penetrate into their fixing spaces. This merging of the molding unit with the lead frame structure provides comprehensive protection to all LED chips in a single manufacturing step, rather than requiring separate protective measures for each chip, thus maintaining ease of manufacture while significantly improving impact resistance.
Data Source
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AI summary
Provided is a light emitting device. The light emitting device includes: a plurality of lead frame units spaced apart from each other, each of the lead frame units being provided with at least one fixing space perforating a body thereof in a vertical direction; a light emitting diode chip mounted on one of the lead frame units; and a molding unit that is integrally formed on top surfaces of the lead frame units and in the fixing spaces to protect the light emitting diode chip.