Light Emitting Element Electrode Network for Uniform Current Distribution
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Solution Overview
Problem
Conventional light emitting elements exhibit uneven emission due to higher current density near the pad electrode, leading to non-uniform brightness, as current density decreases with distance from the pad.
Innovation Solution
The design includes an upper electrode with a first extending portion along the semiconductor layer's periphery, connected to pad portions on opposite sides, and additional extending portions that distribute current more evenly by connecting these pads, ensuring uniform current distribution across the semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a pad electrode with fine wire electrode is used to supply current, then current can be supplied to the semiconductor layer, but current density becomes uneven with higher density near the pad and lower density farther away, resulting in uneven emission
Solution Approach 1:
The electrode structure is segmented into multiple components: a pad electrode, multiple extending portions extending from the pad in different directions, and multiple bridge portions connecting these extending portions. This segmentation allows current to be distributed through multiple pathways across the semiconductor layer, preventing current concentration at a single location and achieving more uniform current density and emission throughout the device.
2Device complexity
If current is supplied through a single pad electrode, then the structure is simple, but current density decreases with distance from the pad, causing non-uniform brightness
Solution Approach 1:
The electrode structure transitions from a two-dimensional pad to a three-dimensional network of extending portions and bridge portions that span across the semiconductor layer. This dimensional expansion creates multiple current supply pathways at different spatial locations, enabling uniform current distribution across the entire active area while maintaining reasonable structural complexity.
3Illumination intensity
If the electrode extends far from the pad to cover the entire semiconductor layer, then current distribution improves, but the distance from the pad increases and current density decreases
Solution Approach 1:
Multiple extending portions and bridge portions are merged into an integrated electrode network that collectively supplies current across the semiconductor layer. This merged structure creates multiple parallel current pathways, effectively reducing the distance current must travel from any point on the semiconductor layer to the nearest electrode component, thereby maintaining high current density while achieving uniform emission.
Data Source
AI summary
A light emitting element includes a semiconductor layer; an upper electrode disposed on an upper surface of the semiconductor layer; and a lower electrode disposed on a lower surface of the semiconductor later. In a plan view, the upper electrode includes a first extending portion extending in an approximately rectangular shape along an outer periphery of the semiconductor layer, a first pad portion connected to a first side among four sides of the first extending portion, a second pad portion connected to a second side that is opposite to the first side, among the four sides of the first extending portion, and a second extending portion and a third extending portion, each disposed in a region surrounded by the first extending portion, the second extending portion and the third extending portion each connecting the first pad portion and the second pad portion.