Angled Transparent Substrate LED Light Extraction
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Solution Overview
Problem
Conventional light-emitting diode (LED) devices with transparent substrates face reduced light efficiency due to light absorption when the size of the LED chip increases, as more reflected light passes through the multi-quantum well in the light-emitting layer, leading to suboptimal brightness and light extraction.
Innovation Solution
An encapsulated light-emitting diode device is designed with a transparent substrate having a first and second surface forming an included angle greater than zero, where a light-emitting diode chip is positioned on the first surface covered by a circular projection of transparent glue, and a second transparent glue is applied on the second surface, enhancing light extraction efficiency through omnidirectional light emission and reflection from a carrier's reflective inside wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the size of the light-emitting diode chip is increased, then the light output is improved, but the light efficiency is reduced due to light absorption in the multi-quantum well layer
Solution Approach 1:
The patent changes the mounting angle of the transparent substrate from parallel (0 degrees) to an inclined angle (30-60 degrees) relative to the carrier surface. This dimensional change in orientation causes reflected light to exit through the lateral surface of the transparent substrate rather than passing back through the light-emitting layer, thereby resolving the light absorption problem while maintaining high light output from larger LED chips
2Illumination intensity
If the transparent substrate thickness is adjusted, then the light extraction brightness is improved, but the structural stability and manufacturing precision are compromised
Solution Approach 1:
The patent changes the geometric parameter of the substrate orientation (inclination angle) rather than adjusting the substrate thickness. This parameter change allows optimization of light extraction efficiency through angular control (30-60 degrees) without compromising the structural integrity and manufacturing precision of the substrate thickness
3Ease of manufacture
If the light extraction surface is oriented parallel to the LED chip attached surface, then the assembly is simplified, but the reflected light cannot be effectively extracted
Solution Approach 1:
The patent introduces an angular dimension to the substrate orientation, positioning it at 30-60 degrees relative to the carrier surface. This dimensional change enables reflected light to be redirected toward the lateral extraction surface, significantly improving light extraction efficiency while maintaining relatively simple assembly procedures
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 solution significantly improves light extraction efficiency by allowing omnidirectional light emission and reflection, reducing light absorption and enhancing brightness, while allowing for tunable light extraction distribution by adjusting the included angle between the transparent substrate and the carrier surface.
Implementation Method 1
the light extracted from the light-emitting layer of the light-emitting diode chips are 360 degree
Implementation Method 2
the light emitting downward is reflected to the front of the light extraction side by the reflecting layers or extracted from the transparent substrates
Implementation Method 3
the light emitting downward is reflected to the front light extraction surface 4 or the lateral light extraction surface 5 by the reflector 2
Data Source
AI summary
An encapsulated light-emitting diode device is disclosed. The encapsulated light-emitting diode device includes a circuit carrier including a surface; a light-emitting device including a transparent substrate, the transparent substrate including a first surface and a second surface, and the first surface and the surface of the circuit carrier includes an included angle larger than zero; a light-emitting diode chip located on the first surface of the transparent substrate; and a first transparent glue covering the light-emitting diode chip and formed on the first surface; and a second transparent glue formed on the second surface corresponding to the first transparent glue; wherein the first transparent glue has a circular projection on the first surface and the light-emitting diode chip is substantially located at the center of the circular projection.