Monolithic Multi-Peak LED Structure for Phosphor-Free White Light
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Solution Overview
Problem
Conventional white LEDs require multiple well layers and phosphor-based red light emitting diodes, which complicate manufacturing, limit space, and suffer from efficiency issues and color variation with viewing angles, making them unsuitable for micro LED displays.
Innovation Solution
A monolithic light emitting diode with a novel structure emitting multiple peak wavelengths without phosphors, featuring a light emitting region with separate portions for blue and green light, and a separation layer to achieve a multi-band spectrum and improved external quantum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple well layers and phosphor-based red light emitting diodes are used to implement various colors, then color implementation is achieved, but manufacturing process becomes complicated and package size increases
Solution Approach 1:
The patent merges multiple light emitting portions (first light emitting portion for green/yellow light, second light emitting portion for blue light) into a single monolithic LED structure. This integration eliminates the need for separate phosphor materials and multiple discrete components, thereby simplifying the manufacturing process while maintaining the capability to emit multiple colors through the different light emitting portions with different peak wavelengths
Solution Approach 2:
The single LED structure performs multiple functions by incorporating different light emitting portions that emit at different wavelengths. The first light emitting portion emits green or yellow light while the second light emitting portion emits blue light, allowing one device to replace what would traditionally require multiple separate components or phosphor materials
2Adaptability or versatility
If multiple well layers and phosphor-based red light emitting diodes are used to implement various colors, then color implementation is achieved, but package size becomes large
Solution Approach 1:
The patent combines multiple light emitting functions into a single monolithic LED chip structure. By integrating the first light emitting portion and second light emitting portion within one device, the package size is significantly reduced compared to using separate phosphor materials and multiple discrete LED components, making it suitable for micro LED display applications
Solution Approach 2:
The patent transitions from a planar arrangement of separate components to a vertical stacked structure where different light emitting portions are arranged in layers. This dimensional reorganization allows multiple light emitting functions to be packed into a smaller footprint area, reducing the overall package size while maintaining color versatility
3Illumination intensity
If phosphide-based semiconductor is used for red light emitting diode, then red light emission is achieved, but efficiency decreases as light emitting area decreases
Solution Approach 1:
The patent changes the material composition parameter by using InGaN-based nitride semiconductor for the second light emitting portion that emits blue light. This material substitution enables efficient light emission even at small light emitting areas, overcoming the efficiency degradation issue associated with phosphide-based semiconductors in miniaturized devices
4Illumination intensity
If phosphide-based red light emitting diode is used, then red light emission is achieved, but color changes depending on viewing angles
Solution Approach 1:
The patent changes the material composition from phosphide-based semiconductor to InGaN-based nitride semiconductor. This parameter change results in improved color stability across different viewing angles, as the nitride semiconductor material exhibits more consistent optical properties and less sensitivity to viewing angle variations compared to phosphide-based materials
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
Enables the production of white light with enhanced external quantum efficiency and stable color across viewing angles, suitable for micro LED displays without the need for phosphors, improving manufacturing simplicity and efficiency.
Implementation Method 1
a light emitting region disposed between the first conductivity type semiconductor region and the second conductivity type semiconductor region, in which the light emitting region includes a first light emitting portion, a second light emitting portion
Data Source
AI summary
A light emitting diode according to an exemplary embodiment of the present disclosure includes a first conductivity type semiconductor layer; an active region including a barrier layer and a well layer; a strain control layer disposed between the first conductivity type semiconductor layer and the active region; a superlattice layer disposed between the strain control layer and the active region; a second conductivity type semiconductor layer disposed on the active region; and an electron blocking layer disposed between the active region and the second conductivity type semiconductor layer, in which the first conductivity type semiconductor layer and the well layer are represented by a predetermined formula, and a ratio of a mole fraction of In to a mole fraction of Ga in the first conductivity type semiconductor layer and a ratio of a mole fraction of In to a mole fraction of Ga in the well layer satisfy a predetermined equation.