LED Package Protrusions Prevent Resin Burrs
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Solution Overview
Problem
Conventional LED manufacturing methods, such as transfer molding, often result in resin burrs due to the resin flowing into gaps between lead frames and molds, leading to bonding failures and requiring additional steps to remove burrs, which can also reduce LED output by damaging plating layers.
Innovation Solution
A package design with lead electrodes featuring front and back surface protrusions exposed outside the plating layer, which are shaped to prevent resin flow into these areas during molding, using a mold with corresponding projections to guide the resin and minimize contact with the lead frames, thus suppressing burr formation without reducing LED output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transfer molding is used to manufacture LED, then production efficiency is improved, but resin burrs are generated causing bonding failures
Solution Approach 1:
The plating layer is raised to form protrusions at the border of the LED mounting portion before the molding process. This preliminary action creates a physical barrier that prevents resin from entering the gap between the lead frame and mold, thereby preventing burr formation that would cause bonding failures, while still allowing the transfer molding process to proceed efficiently.
Solution Approach 2:
The protruding plating layer acts as a preventive measure against resin intrusion. By creating this raised barrier in advance, the invention counteracts the harmful effect of resin flow into the gap, eliminating the need for subsequent burr removal steps and ensuring bonding quality without compromising production efficiency.
2Manufacturing precision
If pressing force is increased to prevent resin flow, then burr generation is reduced, but the plating layer is crushed reducing LED output
Solution Approach 1:
The plating layer is pre-raised to form protrusions that extend beyond the metal portion border. This preliminary structural preparation creates a natural barrier against resin flow, eliminating the need for high pressing force during molding. Consequently, the plating layer is protected from crushing while still achieving effective burr suppression.
3Ease of manufacture
If conventional molding is used, then manufacturing process is simple, but burr removal steps are required increasing complexity
Solution Approach 1:
The plating layer is raised to form protrusions before molding, creating a built-in barrier against resin intrusion. This preliminary structural modification eliminates the need for subsequent burr removal steps, maintaining process simplicity while reducing the number of manufacturing steps required.
4Manufacturing precision
If plating layer is raised to form protrusion, then resin flow is prevented, but mold contact damages plating glossiness
Solution Approach 1:
The plating layer is raised to form protrusions that extend beyond the metal portion border before molding. This preliminary action creates a protective barrier that prevents resin intrusion while the mold contacts only the protruding plating surface, which does not affect the critical LED mounting area's glossiness.
Data Source
AI summary
A package for mounting a light emitting element includes a recess; a pair of lead electrodes exposed at a bottom surface of the recess; a plating layer covering a surface of each of the pair of lead electrodes; and a resin molded body retaining the pair of lead electrodes, and forming an area between the pair of lead electrodes at the bottom surface of the recess and a lateral surface of the recess. At least one of the lead electrodes has a front surface protrusion that is linearly formed along the resin molded body at the bottom surface of the recess and along a periphery of the bottom surface of the recess, and a back surface protrusion that is formed at a position at a back surface opposite to a position of the front surface protrusion, and at least a tip of each of the front surface protrusion and the back surface protrusion is exposed outside the plating layer.