Resin LED Package Molding for Strong Lead Frame Adhesion
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Solution Overview
Problem
Existing methods for manufacturing light emitting devices using thermoplastic resins face issues such as poor adhesion between the lead frame and the resin, difficulty in molding complex shapes, and significant light deterioration over time.
Innovation Solution
A method involving the use of a thermosetting resin with a light reflecting material, where a lead frame with notch parts is sandwiched by molds and the thermosetting resin is transfer-molded to form a resin-molded body, enhancing adhesion and allowing for the production of multiple light emitting devices efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic resin is used for the resin-molded body, then the molding process is simple, but the adhesion with the lead frame is poor and light deterioration occurs
Solution Approach 1:
The patent changes the material parameter from thermoplastic resin to thermosetting resin. This parameter change fundamentally alters the bonding mechanism from mechanical interlocking to chemical adhesion, resolving the adhesion problem while maintaining molding feasibility through transfer-molding technology.
Solution Approach 2:
The patent uses composite materials by combining thermosetting resin with light-reflecting materials (such as titanium oxide or barium sulfate). This composite approach simultaneously achieves strong adhesion to the lead frame, high light reflectivity to prevent deterioration, and suitable molding properties.
2Reliability
If thermosetting resin is used for the resin-molded body, then adhesion with the lead frame improves, but the resin fluidity is lower making complex shape molding difficult
Solution Approach 1:
The patent replaces the conventional injection-molding mechanical system with a transfer-molding system. In transfer-molding, the resin is pre-formed in a separate chamber and then transferred to the mold cavity under pressure, allowing thermosetting resin to adequately fill complex cavities despite its lower fluidity compared to thermoplastic resin.
3Productivity
If conventional transfer-molding method is used, then light emitting devices can be manufactured, but a great amount of resin in the runner part is discarded
Solution Approach 1:
The patent applies the discarding and recovering principle by designing the mold to enable easy removal and recovery of the runner part. The runner is designed as a separable component that can be detached from the main resin-molded body, allowing the valuable thermosetting resin in the runner to be recovered and reused, thereby reducing material waste while maintaining efficient production.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves adhesion between the lead frame and the thermosetting resin, enables the production of light emitting devices with high optical reflectivity, and reduces production costs by minimizing discarded resin and increasing manufacturing efficiency.
Implementation Method 1
a resin-molded body made of a thermosetting resin containing a light reflecting material
Data Source
AI summary
A light emitting device includes: a resin package comprising a first lead, a second lead, and a resin part; and a light emitting element disposed on the first lead. The resin package has a rectangular shape in top view and comprises a first outer lateral surface, a second outer lateral surface on a side opposite the first outer lateral surface, a third outer lateral surface, and a fourth outer lateral surface on a side opposite the third outer lateral surface. At the first outer lateral surface, the first lead is exposed from the resin part, and the first lead and a portion of the resin part located at a lateral edge of the first lead are substantially coplanar with each other.