LED Ramp Substrate for Light Extraction
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) face challenges in maximizing light extraction efficiency due to the limitations of their substrate designs, which can lead to reduced light output and heat dissipation.
Innovation Solution
A light-emitting element design featuring a supportive substrate with a non-parallel bottom surface and a reflective layer, along with a metal substrate that does not directly contact the supportive substrate, enhances light extraction efficiency by directing light towards the sides and facilitating heat dissipation through a composite substrate structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional flat substrate is used in LED, then the structure is simple and easy to manufacture, but light extraction efficiency is reduced and heat dissipation is poor
Solution Approach 1:
The substrate is designed with an asymmetric ramp structure where a portion of the bottom surface is removed to form a non-parallel configuration. This asymmetric geometry redirects light that would otherwise be trapped toward the sides and improves light extraction efficiency without significantly complicating the manufacturing process
Solution Approach 2:
The invention transitions from a conventional two-dimensional flat substrate to a three-dimensional ramp structure by removing a portion of the bottom surface. This dimensional change creates angular surfaces that redirect light paths and improve light extraction while maintaining manufacturing feasibility
2Device complexity
If a conventional flat substrate is used in LED, then the structure is simple, but heat dissipation performance is poor
Solution Approach 1:
The asymmetric ramp structure increases the surface area and creates multiple angles for heat dissipation. The non-parallel configuration allows heat to spread more effectively across the substrate and into the underlying metal substrate, improving thermal management
Solution Approach 2:
By transitioning from a flat 2D substrate to a 3D ramp structure, the invention creates additional thermal pathways and increases the effective heat dissipation surface area, enabling better heat management without proportionally increasing structural complexity
3Device complexity
If the metal substrate directly contacts the supportive substrate, then the structure is simple, but light extraction efficiency is reduced
Solution Approach 1:
A portion of the supportive substrate is removed (taken out) to create the ramp structure, and the metal substrate is positioned to not directly contact the supportive substrate. This extraction creates the necessary geometric configuration for improved light extraction while maintaining structural integrity through the ramp design
Solution Approach 2:
The ramp structure acts as an intermediary between the supportive substrate and the metal substrate. This intermediate geometric feature redirects light paths and prevents direct contact between the metal substrate and supportive substrate, thereby improving light extraction efficiency while maintaining structural connection
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 described design significantly improves light extraction efficiency and heat dissipation, leading to enhanced performance and reliability of LED devices.
Implementation Method 1
A reflective layer is formed under the first bottom surface
Implementation Method 2
A part of the supportive substrate is removed from the bottom plane thereof to form a first bottom surface which is not parallel to the active layer
Implementation Method 3
a metal substrate is formed under the reflective layer wherein the metal substrate does not directly contact with the supportive substrate
Data Source
AI summary
A light-emitting device includes a light-emitting stacked layer having an active layer, and a composite substrate located under the light-emitting stacked layer. The composite substrate includes a supportive substrate having a top surface and a bottom surface non-parallel to the active layer; a metal substrate located under the supportive substrate; and a reflective layer located between the supportive substrate and the metal substrate.