Light Emitting Element Uniform Current Density via Local Quality
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Solution Overview
Problem
Conventional light-emitting elements face reliability issues due to uneven current density across light-emitting cells, which can lead to electrical failures and reduced reliability, especially under conditions like overcurrent or electrostatic discharge.
Innovation Solution
A light-emitting element design with uniformly sized active layers across cells, where the planar area of each cell is carefully managed to ensure consistent current distribution, and boundary areas are arranged to scatter light and prevent line alignment, enhancing uniformity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the second electrode pad is placed in the light-emitting element, then the light extraction efficiency is improved, but the planar area of the active layer in the ninth emission area becomes less than the planar area of the active layer in the other first to eighth emission areas, causing uneven current density
Solution Approach 1:
The patent applies local quality by making the ninth emission area (where the second electrode pad is located) have a larger planar area than the other emission areas. This local adjustment compensates for the area reduction caused by the electrode pad placement, ensuring that the active layer area in the ninth emission area is equal to or greater than that in other areas, thereby maintaining uniform current density across all emission areas while preserving the light extraction efficiency improvement from the electrode pad structure.
2Illumination intensity
If the planar area of the active layer in the ninth emission area is reduced due to electrode pad placement, then the light extraction efficiency is improved, but the current density in the ninth emission area becomes greater than in other areas, causing damage to the connection metal
Solution Approach 1:
The patent applies local quality by making the ninth emission area (where the second electrode pad is located) have a larger planar area than the other emission areas. This local adjustment compensates for the area reduction caused by the electrode pad placement, ensuring that the active layer area in the ninth emission area is equal to or greater than that in other areas, thereby maintaining uniform current density across all emission areas while preserving the light extraction efficiency improvement from the electrode pad structure.
3Ease of manufacture
If all light-emitting cells have the same planar area, then the manufacturing process is simplified, but the current density becomes uneven when electrode pads are placed, leading to reliability issues
Solution Approach 1:
The patent applies local quality by making the ninth emission area (where the second electrode pad is located) have a larger planar area than the other emission areas. This local adjustment compensates for the area reduction caused by the electrode pad placement, ensuring that the active layer area in the ninth emission area is equal to or greater than that in other areas, thereby maintaining uniform current density across all emission areas while preserving the light extraction efficiency improvement from the electrode pad structure.
Data Source
AI summary
A light-emitting element provides a substrate; a plurality of light-emitting cells arranged on the substrate and spaced apart from each other; a connection wire configured to electrically interconnect the light-emitting cells; a first bonding pad electrically connected to the second conductive semiconductor layer of a first light-emitting cell among the light-emitting cells; and a second bonding pad electrically connected to the first conductive semiconductor layer of a second light-emitting cell among the light-emitting cells, wherein a boundary area includes a first boundary disposed between the light-emitting cells adjacent to each other in a first direction among the plurality of light-emitting, and wherein all of the first boundary areas are spaced apart from each other in the first direction.