LED Lead Stamping for Yield and Stability
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Solution Overview
Problem
The manufacturing yield of light emitting devices is reduced due to the difficulty in increasing the number of lead pieces that can be punched out from a single sheet of metal, leading to poor standing stability and potential inclination during mounting.
Innovation Solution
A light emitting device with a cuboid package and leads that have convex and concave parts formed by stamping, allowing increased lead pieces from a single sheet and improved stability through solder distribution during mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leads with wing parts are punched out from sheet metal, then the leads can be exposed at the inner peripheral face to reduce degradation and discoloration, but it is difficult to increase the number of lead pieces that can be punched out from a single piece of sheet metal
Solution Approach 1:
The lead structure is segmented into a body part and multiple terminal parts with convex and concave portions. This segmentation allows multiple leads to be arranged more efficiently on the sheet metal, increasing the number of leads that can be punched out from a single sheet while maintaining the protective exposure at the inner peripheral face.
Solution Approach 2:
The lead structure utilizes three-dimensional convex and concave portions instead of traditional two-dimensional wing parts. This dimensional change allows for more compact arrangement and higher density of leads on the sheet metal, improving manufacturing yield while maintaining functionality.
2Device complexity
If the light emitting device has a low depth to height ratio, then the device structure is simpler, but the standing stability is poor and the device may incline during mounting
Solution Approach 1:
The convex and concave portions are formed in advance during the stamping process, creating preliminary structural features that will later provide stability during mounting. These pre-formed features act as mechanical interlocks with the solder, preventing inclination before the actual mounting occurs.
Solution Approach 2:
The lead structure incorporates asymmetric convex and concave portions that create an uneven distribution of mechanical strength. This asymmetry provides targeted support in critical areas to prevent inclination during mounting, while maintaining overall structural simplicity.
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 solution enhances manufacturing yield by increasing the number of lead pieces and improves standing stability by allowing solder to exert stress in the side face direction, reducing inclination during mounting.
Implementation Method 1
The lead has a first convex part that protrudes toward a light emission face side and is exposed from the molded article at the inner peripheral face of the mounting recess, and a first concave part that is formed in a rear face of the first convex part. The first convex part is formed by stamping form the rear face side
Implementation Method 2
when the light emitting device is mounted, if the rear face provided on the opposite side from the light emission face is soldered to the mounting face, the light emitting device can be pulled by the solder and end up being inclined
Data Source
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AI summary
In a light emitting device (100), a first lead (50) has a first terminal part (52) that is contiguous with a first connector (51). The first terminal part (52) includes a first convex part (520b) that is exposed from a molded article (40) at the inner peripheral face (11B) of a mounting recess (11), and a first concave part (521 a) that is formed in the rear face (10B) of the first convex part (520b).