Molded Package Lead Recess for LED Heat Dissipation
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Solution Overview
Problem
Light emitting devices using frame insert type resin packages face challenges with heat dissipation and adhesiveness between the molded resin and leads, leading to potential separation of leads from the resin package and inefficient heat dissipation.
Innovation Solution
A molded package design featuring a molded resin with a recess for a light emitting element, where leads are partially exposed from the bottom and rear surfaces, with cutouts or through holes that allow resin to fill and enhance bonding strength, and a sealing resin to protect the element and improve heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If leads are exposed from the rear surface of the molded resin to improve heat dissipation, then heat dissipation properties are improved, but adhesiveness between the molded resin and leads deteriorates causing leads to separate
Solution Approach 1:
The lead is divided into multiple functional zones: a first exposed surface for heat dissipation, a second exposed surface for electrical connection, and a recessed portion that is embedded in the molded resin. This segmentation allows each portion to serve its specific function while maintaining overall structural integrity and adhesiveness.
Solution Approach 2:
Different portions of the lead are given different properties: the first surface is exposed for thermal conduction, the second surface is exposed for electrical connection, and the recessed portion is embedded for mechanical anchoring. This local differentiation resolves the contradiction by optimizing each region for its specific purpose.
2Reliability
If leads are fully embedded in molded resin to improve adhesiveness, then adhesiveness between molded resin and leads is improved, but heat dissipation properties deteriorate
Solution Approach 1:
The lead structure is segmented into embedded and exposed portions, allowing simultaneous achievement of mechanical anchoring (through embedding) and thermal conduction (through exposed surfaces).
Solution Approach 2:
The lead has different local properties: embedded portions for mechanical strength and exposed portions for heat dissipation. This local quality differentiation allows the lead to simultaneously achieve both adhesiveness and heat dissipation.
3Reliability
If cutouts or through holes are provided in leads to enhance bonding with resin, then adhesiveness is improved, but device complexity increases
Solution Approach 1:
The recessed portion is formed in advance during lead fabrication, creating a pre-prepared anchoring structure that simplifies the subsequent molding process and enhances bonding without requiring complex post-processing.
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
The design effectively enhances heat dissipation and bonding strength between the leads and resin, preventing lead separation and improving the overall performance of light emitting devices by ensuring efficient heat transfer and protection of the light emitting element.
Implementation Method 1
the lead recess being filled with a resin fully covering an inner surface thereof
Implementation Method 2
heat generated by a light emitting element mounted in a recess of the resin package can be effectively discharged through the leads to a mounting substrate
Data Source
AI summary
A molded package, including: a molded resin having a recess for accommodating a light emitting element; and a lead disposed at a bottom of the molded resin, a part of one surface of the lead being exposed from a bottom surface of the recess of the molded resin, the other surface of the lead including an exposed part and a lead recess, the exposed part being exposed from a rear surface of the molded resin, the lead recess being filled with a resin fully covering an inner surface thereof, the lead including a cutout or a through hole extending from the one surface to the other surface, a first edge of the cutout or the through hole closer to a center of the recess at the other surface being located inside the lead recess and covered with the resin.