Monolithic Multi-Wavelength LED Structure Without Phosphors
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) face limitations in implementing multiple colors due to their single narrow full width at half maximum, requiring multiple LEDs or phosphors, which complicates manufacturing and restricts applications, especially in micro LED displays where red light sources using phosphide-based semiconductors are inefficient and sensitive to temperature.
Innovation Solution
A monolithic LED structure with multiple light emitting portions, including a separation layer and electron blocking layer, allows for the emission of multiple peak wavelengths without phosphors, enhancing external quantum efficiency and enabling white light production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple light emitting diodes or phosphors are used to implement various colors, then color variety is improved, but device complexity and package size increase
Solution Approach 1:
The patent combines multiple light emitting portions with different peak wavelengths (first light emitting portion with peak wavelength λ1, second light emitting portion with peak wavelength λ2) into a single integrated LED device. This merging eliminates the need for separate LEDs or phosphor materials, achieving color variety while reducing device complexity and package size to a single chip level.
Solution Approach 2:
The single LED device performs multiple functions by emitting light at multiple peak wavelengths simultaneously. The light emitting region is designed to generate both first light (wavelength λ1) and second light (wavelength λ2), making the device universal for various color applications without requiring multiple components.
2Adaptability or versatility
If phosphide-based semiconductor is used for red light source in micro LED display, then red light emission is achieved, but efficiency decreases and temperature sensitivity increases
Solution Approach 1:
The patent changes the material composition parameters of the light emitting portions to optimize performance. By adjusting the indium content and using specific semiconductor material compositions (such as InGaN with controlled indium percentages), the device achieves red light emission while maintaining high efficiency and reduced temperature sensitivity compared to conventional phosphide-based solutions.
3Adaptability or versatility
If phosphors are used for wavelength conversion, then multiple wavelengths are achieved, but manufacturing complexity and space requirements increase
Solution Approach 1:
The patent extracts and eliminates the phosphor conversion layer from the optical path by directly generating multiple wavelengths through multiple light emitting portions within the LED structure itself. This removal of phosphors simplifies the manufacturing process and reduces space requirements while maintaining multi-wavelength capability.
4Adaptability or versatility
If different light emitting diodes are used for different colors, then color coverage is improved, but space occupation increases
Solution Approach 1:
The patent merges multiple light emitting functions into a single compact LED chip, where the light emitting region contains multiple portions with different peak wavelengths. This integration dramatically reduces the occupied area compared to using separate LEDs for each color, enabling compact micro LED display applications with full color coverage.
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 proposed LED structure efficiently emits multi-band spectrum light at a single chip level, improving external quantum efficiency and addressing color variation issues across viewing angles.
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
Figure 1~2
Figure 3
Figure 4A
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 the following formula (1), 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 the following equation 1: AxByCzD1−xyz (where A is an element selected from Al, In, and Ga, B is an element selected from Al, In, and Ga, C is an element selected from Al, In, and Ga, D is nitrogen, A, B, and C are different elements from one another, x+y+z=0.5, and 0≤x, y, z≤0.5); and 0.2≤Min/Mgawell−Min/Mgafirst≤0.7.