Light Emitting Element Reflector Layout for Higher Light Extraction
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Solution Overview
Problem
Existing light emitting elements with a conductive member under a semiconductor structure suffer from reduced light extraction efficiency due to light absorption by the conductive member.
Innovation Solution
A light emitting element design that includes a conductive member, a reflecting layer, an insulation layer, a semiconductor structure, n-electrode, and p-electrode, where the reflecting layer is positioned in through holes of the conductive member to enhance light reflection and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conductive member is provided under a semiconductor structure to reflect light upward, then light reflection is achieved, but the conductive member absorbs a portion of the outgoing light, reducing light extraction efficiency
Solution Approach 1:
An insulation layer is introduced as an intermediary between the conductive member and the semiconductor structure. This insulation layer has a refractive index lower than the semiconductor structure, creating an optical interface that reduces light absorption by the conductive member while maintaining electrical connectivity through through-holes.
Solution Approach 2:
The insulation layer is designed with through-holes at specific locations where electrical connection is needed, while maintaining continuous insulation in other areas to optimize optical performance. This localized differentiation allows simultaneous achievement of electrical connectivity and optical efficiency.
2Illumination intensity
If the reflecting layer is positioned to overlap the emission layer in plan view, then light extraction efficiency is maximized, but the structural complexity increases
Solution Approach 1:
The problem of positioning the reflecting layer is solved by considering the planar projection (plan view) dimension. By ensuring the reflecting layer's projection overlaps with the emission layer's projection, optimal light extraction is achieved without requiring complex three-dimensional positioning, thus simplifying the overall structure.
Solution Approach 2:
The insulation layer serves multiple functions simultaneously: it provides electrical insulation, manages optical refractive indices to reduce absorption, and through its through-hole pattern, enables electrical connectivity. This multi-functionality reduces the need for additional separate components.
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 design significantly improves light extraction efficiency by minimizing light absorption and maximizing reflection, particularly by ensuring the reflecting layer overlaps the emission layer in a plan view.
Implementation Method 1
The reflectance of the reflecting layer for the peak wavelength of the light from the emission layer is higher than the reflectance of the conductive member for the peak wavelength of the light from the emission layer
Data Source
AI summary
A light emitting element includes: a conductive member having a first through hole; a reflecting layer disposed in the first through hole; an insulation layer disposed on the conductive member and the reflecting layer and having second through holes positioned so as not to overlap the first through hole in a plan view; a semiconductor structure including a p-type semiconductor layer disposed on the insulation layer, an emission layer disposed on the p-type semiconductor layer, and an n-type semiconductor layer disposed on the emission layer in part; an n-electrode disposed on and electrically connected to the n-type semiconductor layer; and p-electrode electrically connected to the conductive member. A reflectance of the reflecting layer for a peak wavelength of light emitted from the emission layer is higher than the reflectance of the conductive member for the peak wavelength of the light emitted from the emission layer.