Single-Chip Multi-Band LED Structure Without Phosphor Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light emitting diodes using nitride semiconductors struggle to produce multi-band light efficiently without the use of phosphors, which are costly and inefficient, and mixing multiple diodes complicates the process.
Innovation Solution
A novel light emitting diode structure with a V-pit generation layer, active layer, and sub-emission layer that emits light with different peak wavelengths, allowing for multi-band light emission at a single chip level, including a sub-emission layer with adjustable In content and energy bandgap to control wavelength ranges independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphors are used to convert wavelength to achieve multi-band light emission, then white light can be produced, but cost increases and efficiency decreases due to Stoke's shift
Solution Approach 1:
The patent extracts and eliminates the phosphor conversion layer from the light emitting diode structure. Instead of using phosphors to convert wavelength, the invention directly generates multi-band light emission through quantum well structures with different compositions, thereby avoiding energy loss from Stoke's shift and improving overall efficiency
Solution Approach 2:
The patent implements local quality by creating quantum well regions with different indium compositions (first quantum well with lower In content for blue light, second quantum well with higher In content for green/yellow light) within the same active layer. This allows different regions to emit different wavelengths directly, achieving multi-band emission without phosphors
2Illumination intensity
If multiple light emitting diodes are mixed together to produce white light, then multi-band emission is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges multiple light emission functions into a single light emitting diode chip by integrating first and second quantum well regions with different compositions within one active layer. This allows blue and green/yellow light to be generated simultaneously in the same device, eliminating the need to mix multiple separate diodes and simplifying the overall structure
Solution Approach 2:
The patent makes a single light emitting diode universal by enabling it to perform multiple functions: emitting both blue light (from first quantum well) and green/yellow light (from second quantum well) simultaneously. This multi-functional design allows one chip to replace what would traditionally require multiple separate components
3Adaptability or versatility
If conventional quantum well structure is used with varied compositions, then different wavelengths can be targeted, but independent control according to wavelength range is difficult and efficiency is reduced
Solution Approach 1:
The patent segments the quantum well structure into distinct first and second quantum well regions with different indium compositions and thicknesses. The first quantum well (lower In content, thinner) is optimized for blue light emission, while the second quantum well (higher In content, thicker) is optimized for green/yellow light emission. This segmentation enables independent control and optimization of each wavelength range, improving efficiency while maintaining versatility
Solution Approach 2:
The patent applies local quality by giving different regions within the active layer distinct properties: the first quantum well region has lower In content and smaller thickness for blue light, while the second quantum well region has higher In content and larger thickness for green/yellow light. This localized differentiation allows each region to be independently optimized for its specific wavelength range, achieving both versatility and high efficiency
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 structure enables efficient multi-band light emission with improved light efficiency, allowing for the production of white light with adjustable correlated color temperature and high color rendering index, reducing the need for multiple diodes and phosphors.
Implementation Method 1
a sub-emission layer interposed between the n-type nitride semiconductor layer and the p-type nitride semiconductor layer and adjacent to the active layer. The sub-emission layer may emit light having a peak wavelength within a region of wavelengths shorter than a peak wavelength of the first well region
Implementation Method 2
an active layer disposed on the V-pit generation layer, and including a first well region formed along a flat surface of the V-pit generation layer and a second well region formed in the V-pit of the V-pit generation layer
Data Source
AI summary
A light emitting diode includes an n-type nitride semiconductor layer, a V-pit generation layer disposed on the n-type nitride semiconductor layer and having V-pits, an active layer disposed on the V-pit generation layer and including a first well region formed along a flat surface of the V-pit generation layer and a second well region formed in the V-pit of the V-pit generation layer, a p-type nitride semiconductor layer disposed on the active layer and a sub-emission layer interposed between the n-type nitride semiconductor layer and the p-type nitride semiconductor layer and disposed near the active layer. The sub-emission layer may emit light having a peak wavelength within a range of wavelengths shorter than a peak wavelength of the first well region, and light emitted from the light emitting diode is within a range of 0.205≤X≤0.495 and 0.265≤Y≤0.450 in CIE color coordinates (X, Y).