LED Contact Electrodes with Arc Sides for Current Uniformity
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Solution Overview
Problem
Conventional mini/micro flip-chip LEDs face issues with current accumulation at sharp tips of metal layers leading to burning and electrode damage, as well as height differences causing electrode fracture, which result in aging and malfunctioning.
Innovation Solution
The design includes a light-emitting diode with a substrate, a light-emitting unit, and contact electrodes where the projection of the electrodes on the substrate is rectangular-like with arc sides, eliminating sharp points and facilitating uniform current distribution, and an insulating layer with through holes defined by gentle slopes to reduce the risk of electrode failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the metal layers have strip-like shapes with sharp ends to facilitate current spreading, then current distribution is improved, but current accumulates at the sharp tips causing burning and electrode damage
Solution Approach 1:
The patent applies curvature by designing the metal layers with rounded ends instead of sharp tips. The first metal layer has a first end with a first curvature radius and the second metal layer has a second end with a second curvature radius. This curvature eliminates the sharp-tip effect that causes current accumulation and burning, while still maintaining good current spreading capability throughout the metal layer structure.
2Ease of operation
If the insulating layer has height differences due to metal layer placement, then electrode connection is facilitated, but electrode fracture occurs due to the height differences
Solution Approach 1:
The patent applies local quality by creating different curvature radii at different locations of the metal layers. The first metal layer has a first end with a first curvature radius and a second end with a second curvature radius, where the first curvature radius is different from the second curvature radius. This localized variation in curvature allows optimization of current spreading at different regions while avoiding uniform height differences that cause electrode fracture.
3Volume of moving object
If the LED size is reduced to achieve mini/micro scale, then device miniaturization is achieved, but the pitch requirement for patterned structures becomes higher
Solution Approach 1:
The patent applies segmentation by dividing the metal layer structure into multiple distinct layers with different curvatures. The first metal layer and second metal layer are separately configured with different curvature radii at their respective ends. This segmented approach allows each layer to be optimized independently for current spreading while maintaining manufacturability at mini/micro scales without requiring excessively high pattern pitch precision.
Data Source
AI summary
A light-emitting diode includes a substrate, a light-emitting unit, an insulating layer, a first contact electrode and a second contact electrode. The insulating layer is disposed on the light-emitting unit, and has a first through hole and a second through hole. The first contact electrode and the second contact electrode pass through the first through hole and the second through hole to be electrically connected to the light-emitting unit, respectively. A projection of one of the first contact electrode and the second contact electrode on the substrate is rectangular-like in shape and has a first arc side and a second arc side that are opposite to each other.