LED Current Blocking Layer Width Variation
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) suffer from current concentration phenomena and reduced light extraction efficiency due to the presence of a current blocking layer (CBL) which decreases the light emitting area and absorbs or reflects light, leading to inefficient light emission.
Innovation Solution
A light emitting diode design where the current blocking layer has varying line widths, with a thicker width closer to the first pad electrode and a narrower width closer to the second pad electrode, to minimize current concentration and maximize light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a current blocking layer is provided at a lower portion of the pad electrode to prevent light absorption and reflection, then light extraction efficiency is improved, but the light emitting area is decreased and current concentration phenomenon still occurs
Solution Approach 1:
The current blocking layer is designed with varying line widths where the width becomes thinner as it approaches the first pad electrode from the second pad electrode. This local variation in geometry allows the CBL to block current in regions where it is needed while minimizing its impact on the light emitting area near the first pad electrode, thereby resolving the contradiction between preventing current concentration and maximizing light emission area.
2Loss of energy
If a current blocking layer is provided at a lower portion of the pad electrode to prevent light absorption and reflection, then light extraction efficiency is improved, but current concentration phenomenon occurs in a region close to the electrode
Solution Approach 1:
The CBL width is locally adjusted to be thinner near the first pad electrode, which reduces current concentration in the light emitting region while maintaining adequate current blocking function in other areas. This localized geometric modification allows the system to achieve both improved light extraction and more uniform current distribution.
Solution Approach 2:
The current blocking layer is designed with an asymmetric width profile rather than a uniform width. The width varies along the length of the CBL, being thinner near the first pad electrode and thicker near the second pad electrode. This asymmetric design optimizes both light extraction efficiency and current uniformity by adapting the CBL geometry to the specific electrical and optical requirements at different locations.
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
This design enhances current uniformity and light emitting efficiency by reducing the area occupied by the current blocking layer, thereby minimizing light loss and improving overall performance.
Implementation Method 1
A light emitting diode is a p-n junction diode having a characteristic of converting electric energy into light energy. When forward voltage is applied to the light emitting diode, electrons of an p-layer are combined with holes of a p-layer, so that energy corresponding to an energy gap between a conduction band and a valance band is generated. If the energy is realized as light, the light emitting diode emits the energy in the form of light.
Data Source
AI summary
A light emitting diode according to one embodiment comprises: a substrate; a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, which are on the substrate; a first pad electrode part on the first conductive semiconductor layer; a current blocking layer on the second conductive semiconductor layer; a second electrode on the first conductive semiconductor layer and the current blocking layer; and a second pad electrode part on the second electrode, wherein the width of the current blocking layer can become thicker as the current blocking layer becomes closer to the first pad electrode part from the second pad electrode part.