LED Reflective Structure Critical Angle Optimization
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Solution Overview
Problem
Current light-emitting diodes (LEDs) face challenges in improving lighting efficiency, particularly in the design of light-emitting apparatuses where heat dissipation and electrical connections are critical for optimal performance.
Innovation Solution
The implementation of a light-emitting device with a reflective structure, including a substrate, bonding layer, light-emitting stack, and void, where the reflective structure electrically connects to the semiconductor layer at a specific interface, creating a larger critical angle for light emission and enhancing total internal reflection, thereby improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional LED structure is used, then the device is simple in structure, but the lighting efficiency is insufficient
Solution Approach 1:
The LED device is segmented into distinct functional layers including a substrate, bonding layer, light-emitting stack, reflective structure, and void. This segmentation allows each component to be optimized independently for its specific function while contributing to overall lighting efficiency.
Solution Approach 2:
A reflective structure is introduced as an intermediary element between the light-emitting stack and substrate. This reflective structure serves as a mediator to redirect and concentrate light emission, thereby improving lighting efficiency without significantly complicating the overall device architecture.
2Duration of action of stationary object
If heat dissipation is not optimized, then the device structure remains simple, but the operational life is reduced
Solution Approach 1:
A void is extracted and introduced between the substrate and light-emitting stack. This void serves as a heat dissipation pathway that extracts thermal energy from the active region, thereby extending operational life while maintaining relatively simple structural complexity.
3Productivity
If the critical angle for light emission is not optimized, then the interface design is simple, but the light extraction efficiency is low
Solution Approach 1:
The critical angle parameter at the first interface is deliberately changed and optimized to be larger than at the second interface. This parameter change enhances light extraction efficiency by modifying the optical conditions for total internal reflection at different interfaces within the device.
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 configuration enhances the light-emitting device's efficiency by optimizing light emission angles and heat dissipation, leading to improved performance and longer operational life.
Implementation Method 1
A critical angle at the first interface for a light emitted from the light-emitting stack is larger than that at the second interface
Data Source
AI summary
This disclosure discloses a light-emitting device. The light-emitting device includes a light-emitting stack having a first-type semiconductor layer, a second-type semiconductor layer, and an active layer formed between the first-type semiconductor layer and the second-type semiconductor layer; and a reflective structure formed on the first-type semiconductor layer and having a first interface and a second interface. A critical angle at the first interface for a light emitted from the light-emitting stack is larger than that at the second interface. The reflective structure electrically connects to the first-type semiconductor layer at the first interface, and an area of the first interface is more than an area of the second interface in a top view.