LED Covering Dome Structure for Light Extraction and Crack Resistance
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Solution Overview
Problem
The existing semiconductor light-emitting apparatus faces challenges in improving light extraction efficiency and reliability due to the distortion and cracking of sealing members caused by material differences between the sealing resin and the package substrate, which affects the dome-shaped sealing structure.
Innovation Solution
A semiconductor light-emitting apparatus is designed with a covering member that has a dome shape, is convex upward, and is made of a material with a lower refractive index than the translucent substrate, positioned only on the upper surface of the translucent substrate, not in contact with the package substrate, to enhance light extraction efficiency and reduce stress-induced exfoliation and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of the sealing member is increased to form a dome shape, then light extraction efficiency is improved, but distortion caused by material difference between sealing member and package substrate increases
Solution Approach 1:
The patent divides the sealing structure into two separate components: a sealing member that bonds the translucent substrate to the package substrate, and a covering member that forms the dome shape on the translucent substrate. This segmentation allows each component to have optimized thickness and material properties independently, reducing distortion while maintaining light extraction efficiency.
Solution Approach 2:
The translucent substrate acts as an intermediary between the sealing member and the covering member. The covering member is positioned on the translucent substrate rather than directly on the package substrate, which mediates the stress and reduces distortion caused by material differences between the covering member and package substrate.
2Illumination intensity
If the thickness of the sealing member is increased to form a dome shape, then light extraction efficiency is improved, but the sealing member becomes easily exfoliated or cracked
Solution Approach 1:
The patent divides the sealing structure into two separate components: a sealing member that bonds the translucent substrate to the package substrate, and a covering member that forms the dome shape on the translucent substrate. This segmentation allows each component to have optimized thickness and material properties independently, reducing distortion while maintaining light extraction efficiency.
Solution Approach 2:
The translucent substrate acts as an intermediary between the sealing member and the covering member. The covering member is positioned on the translucent substrate rather than directly on the package substrate, which mediates the stress and reduces distortion caused by material differences between the covering member and package substrate.
3Illumination intensity
If the covering member is made with lower refractive index than the translucent substrate, then light extraction efficiency is improved, but the material selection becomes more restricted
Solution Approach 1:
The patent changes the refractive index parameter of the covering member to be lower than that of the translucent substrate. This parameter change optimizes light extraction efficiency by reducing total internal reflection at the interface. Common materials satisfying this condition include silicone resin (refractive index 1.4-1.5) and fluororesin (refractive index 1.35-1.45).
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 improves light extraction efficiency by up to 30% and enhances the reliability of the semiconductor light-emitting apparatus by reducing stress on the covering member, thereby minimizing exfoliation and cracking.
Implementation Method 1
having a lower refractive index than the translucent substrate
Data Source
AI summary
A semiconductor light-emitting apparatus includes: a package substrate; a semiconductor light-emitting element including an anode electrode and a cathode electrode bonded to the package substrate, a semiconductor layer on the anode electrode and the cathode electrode, and a translucent substrate on the semiconductor layer; and a covering member that is in contact with an upper surface of the translucent substrate, has a dome shape that is convex upward, has translucency at an emission wavelength of the semiconductor light-emitting element, has a lower refractive index than the translucent substrate, and that is not in contact with the package substrate.