Inclined Side Surfaces for Light Extraction in LED Devices
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Solution Overview
Problem
Conventional light emitting devices suffer from low luminous efficiency due to internal reflection of light at vertically etched surfaces, which reduces the extraction and external quantum efficiency, limiting their brightness and applicability in various applications.
Innovation Solution
The light emitting device features inclined side surfaces of semiconductor layers, ranging from 20° to 80° from the horizontal plane, allowing light to be emitted externally rather than being reflected internally, thereby enhancing extraction and external quantum efficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vertically etched surfaces are used in light emitting devices, then manufacturing simplicity is maintained, but light extraction efficiency deteriorates due to internal reflection
Solution Approach 1:
The patent applies asymmetry by changing the etched surface from a vertical configuration to an inclined configuration with a specific angle range (20° to 80° from horizontal). This asymmetric modification to the surface geometry fundamentally alters light propagation paths, enabling light to escape at angles that avoid total internal reflection while maintaining manufacturing feasibility through controlled etching processes.
Solution Approach 2:
The patent implements parameter changes by optimizing the inclination angle of the etched surface within a specific range (20° to 80° from horizontal). This parameter optimization balances light extraction efficiency with manufacturing considerations, achieving enhanced luminous performance without requiring complex manufacturing processes. The specific angle range represents a optimized parameter that maximizes light extraction while maintaining ease of manufacture.
2Device complexity
If vertically etched surfaces are used in light emitting devices, then device structure simplicity is maintained, but luminous intensity deteriorates due to internal reflection
Solution Approach 1:
The patent applies asymmetry by replacing the vertical surface configuration with an inclined surface at 20° to 80° from horizontal. This asymmetric geometric modification disrupts the total internal reflection condition that occurs at vertical interfaces, allowing light to be extracted more effectively and significantly enhancing luminous intensity while preserving overall structural simplicity.
Solution Approach 2:
The patent optimizes the surface inclination angle parameter within the range of 20° to 80° from horizontal to maximize light extraction efficiency. This parameter optimization directly enhances luminous intensity by enabling more photons to escape the semiconductor material, while the modification remains sufficiently simple to maintain overall device structure simplicity.
3Ease of manufacture
If vertically etched surfaces are used in light emitting devices, then extraction efficiency deteriorates due to internal reflection, but manufacturing process simplicity is maintained
Solution Approach 1:
The patent applies asymmetry by configuring the etched surface at an inclined angle of 20° to 80° from horizontal rather than vertically. This asymmetric geometry fundamentally changes light extraction dynamics, achieving high extraction efficiency through a manufacturing process that remains relatively simple and compatible with existing semiconductor fabrication techniques.
Solution Approach 2:
The patent optimizes the etched surface inclination angle parameter within the specific range of 20° to 80° from horizontal to achieve high extraction efficiency. This parameter optimization ensures that light extraction performance is maximized while the manufacturing process remains simple and compatible with standard semiconductor fabrication methods.
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 significantly improves luminous intensity and brightness by reducing internal reflection and increasing light extraction, making the devices more suitable for applications requiring high light characteristics.
Implementation Method 1
inclined side surfaces of semiconductor layers, ranging from 20° to 80° from the horizontal plane, allowing light to be emitted externally rather than being reflected internally
Data Source
AI summary
A light emitting device includes a substrate and a plurality of light emitting cells disposed on the substrate. Each light emitting cell includes a first semiconductor layer and a second semiconductor layer, an active layer between the first and the second semiconductors, a conductive material on the second semiconductor layer, an inclined surface, a first insulation layer overlaps each light emitting cell, an electrically conductive material overlaps the first insulation layer to couple two of the plurality of light emitting cells, and a second insulation layer overlaps the electrically conductive material. A light-transmitting material is used in both the first insulation layer and the second insulation layer. The inclined surface is continuous and has a slope of approximately 20° to approximately 80° from a horizontal plane based on the substrate.