Light-Emitting Element With Varying Conductive Layer Width
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Solution Overview
Problem
Light-emitting diodes (LEDs) experience current crowding and non-uniform luminous efficiency due to strong luminescence coupling near electrode pads, leading to reduced light emission uniformity and increased operating voltage.
Innovation Solution
A light-emitting element design featuring a first semiconductor layer, an active layer, and a second semiconductor layer, with a second conductive layer and through electrodes connected via insulating layers, where the widths of the conductive layers and insulating layers are strategically adjusted to reduce current crowding and enhance luminescence coupling uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrode pads are formed by etching the light-emitting structure, then electrical connection is achieved, but current crowding occurs in regions adjacent to the electrode pad
Solution Approach 1:
The patent applies local quality by creating a transparent conductive layer with varying thickness across different regions. The layer has greater thickness in regions adjacent to the electrode pad where current crowding occurs, providing lower electrical resistance locally to counteract the crowding effect, while maintaining uniform thickness in other regions for normal operation.
Solution Approach 2:
The patent changes the physical parameter of the transparent conductive layer by controlling its thickness to vary from 50nm to 200nm across different regions. This parameter change allows the layer to have different electrical resistance characteristics in different areas, specifically reducing resistance near the electrode pad to mitigate current crowding while maintaining appropriate resistance elsewhere.
2Power
If current is concentrated near the electrode pad, then electrical connection efficiency is improved, but luminous efficiency becomes non-uniform
Solution Approach 1:
The transparent conductive layer is designed with non-uniform thickness to create different electrical properties in different regions. Regions near the electrode pad have greater thickness for better electrical connection, while other regions have uniform thickness to maintain consistent light emission characteristics, thus achieving both good electrical connection and uniform luminous efficiency.
Solution Approach 2:
The varying thickness of the transparent conductive layer allows excess current to be diverted or 'skipped' away from regions where it would cause non-uniform luminous efficiency. The thicker portions near the electrode pad provide alternative current pathways that bypass the problematic regions, enabling current to flow more evenly across the light-emitting structure.
3Power
If current density is high near the electrode pad, then electrical conductivity is improved, but heat generation increases
Solution Approach 1:
The transparent conductive layer has locally optimized thickness to manage heat generation. In regions adjacent to the electrode pad where current density is high and heat generation is problematic, the layer has greater thickness providing lower resistance and better heat dissipation. In other regions, the layer maintains uniform thickness to prevent unnecessary heat generation while preserving electrical conductivity.
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 design increases current spreading and heat generation characteristics, resulting in improved luminous efficiency and extended lifetime of the light-emitting element with more uniform light emission.
Implementation Method 1
an insulating layer configured to electrically insulate the plurality of through electrodes from the active layer, the second semiconductor layer, and the second conductive layer
Implementation Method 2
A light-emitting diode (LED) is a light-emitting element that emits light when a current is applied thereto
Data Source
AI summary
Disclosed according to one embodiment is a light-emitting element comprising: a light-emitting structure comprising a first semiconductor layer, an active layer, and a second semiconductor layer; a second conductive layer electrically connected to the second semiconductor layer; a first conductive layer which is disposed in a plurality of via holes passing through the light-emitting structure and second conductive layer and comprises a plurality of through electrodes electrically connected to the first semiconductor layer; an insulation layer for electrically insulating the plurality of through electrodes from the active layer, second semiconductor layer, and second conductive layer; and an electrode pad disposed in an exposed area of the second conductive layer, wherein the farther away the second conductive layer disposed between the plurality of through electrodes is from the electrode pad, the greater the width of the second conductive layer becomes.