Side-View LED Package Lead Positioning for Crack Resistance
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Solution Overview
Problem
Side-view type light emitting devices with a cuboid shape are prone to cracking on the top face when pressure is applied during mounting due to the larger surface area of the molded article not sandwiched between the lead and the nozzle, leading to reduced yield.
Innovation Solution
The light emitting device features a package with leads where the exposed part is positioned more towards the center than the terminal part, providing additional support when pressure is applied from the top face, reducing bending and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the light emitting device is designed as a side-view type with a cuboid shape, then the light emission face is provided on a side face, but the top face readily bends under pressing force from the nozzle, making the molded article susceptible to cracking
Solution Approach 1:
The patent positions the exposed part of the lead more toward the center of the package than the terminal part, creating a preliminary structural support configuration that prevents bending before the nozzle pressure is applied during mounting
Solution Approach 2:
The exposed part of the lead acts as an intermediary support element between the top face and the nozzle, distributing the pressing force and preventing direct transmission of stress to the molded article
2Device complexity
If the top face surface area is larger than the lead contact area, then the device structure is simplified, but the molded article of the top face readily bends under pressing force, reducing yield
Solution Approach 1:
The patent creates a local quality difference by positioning the exposed lead part toward the center, creating a localized support zone that provides enhanced structural integrity where needed without changing the overall device complexity
Data Source
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AI summary
A light emitting device comprises a light emitting element and a package constituted by a molded article and a first lead and a second lead embedded in the molded article, and having a bottom face, a top face disposed opposite to the bottom face, and a light emission face connected to the bottom face and the top face. The first lead has a first terminal part exposed at the bottom face exposed at the top face. The exposed part is provided more toward the center of the package than the first terminal part.