GaN Light-Emitting Element With Gradient Index Films for Light Extraction
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Solution Overview
Problem
Existing light-emitting elements using inorganic semiconductors face challenges in efficiently extracting light while maintaining high reliability and reducing power consumption, particularly when using amorphous glass substrates.
Innovation Solution
The design incorporates a substrate with optical adjustment films that decrease in refractive index with distance from the electroluminescent laminate, along with a sputtering method for functional layers, to enhance light extraction and protect against impurities, using materials like aluminum nitride and silicon nitride for the films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If optical adjustment films are added to enhance light extraction, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the refractive index of optical adjustment films in the wavelength direction. The refractive index is changed from 2.0 to 2.6 at 450 nm wavelength to 1.5 to 2.0 at 650 nm wavelength, optimizing light extraction efficiency across different wavelengths without adding excessive structural complexity
Solution Approach 2:
The patent uses composite materials by combining multiple optical adjustment films with different refractive indices in a layered structure. This composite approach allows gradient refractive index control and improves light extraction efficiency while managing the complexity through material composition rather than structural complexity
2Ease of manufacture
If amorphous glass substrates are used, then manufacturing flexibility is improved, but light extraction efficiency deteriorates
Solution Approach 1:
The patent introduces optical adjustment films as intermediary layers between the amorphous glass substrate and the electroluminescent laminate. These intermediary films with gradient refractive indices (2.0-2.6 at 450 nm, 1.5-2.0 at 650 nm) mediate the optical interface, improving light extraction efficiency while preserving the manufacturing advantages of amorphous glass substrates
3Loss of energy
If refractive index gradient is implemented, then light extraction efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements parameter changes by defining specific refractive index ranges for different wavelengths (2.0-2.6 at 450 nm, 1.5-2.0 at 650 nm) rather than requiring precise single-value control. This approach improves light extraction efficiency while reducing manufacturing precision requirements through parameter ranges
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 results in highly efficient light-emitting elements with reduced power consumption and improved reliability, suitable for both small and large display devices, while also enhancing the durability of the display devices.
Implementation Method 1
The plurality of optical adjustment films is configured so that refractive indices decrease with increasing distance from the electroluminescent laminate
Implementation Method 2
a sputtering method for functional layers
Data Source
AI summary
A light-emitting element includes a substrate, an electroluminescent laminate over the substrate, an anode and a cathode electrically connected to the electroluminescent laminate, and a plurality of optical adjustment films over the electroluminescent laminate. The electroluminescent laminate includes a plurality of functional layers containing a gallium nitride-based material. The plurality of optical adjustment films is configured so that refractive indices decrease with increasing distance from the electroluminescent laminate. The plurality of optical adjustment films may independently contain a material selected from aluminum nitride, silicon nitride, silicon oxide, titanium oxide, zirconium oxide, chromium oxide, aluminum oxide, indium oxide, lead sulfide, and a polymer containing sulfur, halogen, or phosphorus.