Single-Chip Multi-Band LED for Phosphor-Free Color Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light emitting diodes (LEDs) using nitride semiconductors emit monochromatic light, making it difficult to achieve mixed color lighting without the use of multiple LEDs or phosphors, which introduces costs and efficiency losses.
Innovation Solution
A novel LED structure with a V-pit generation layer and multi-quantum well design allows for a single chip to emit light with multiple peak wavelengths, enabling the production of mixed colors such as yellow to white light without the need for phosphors or multiple LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single LED emits monochromatic light, then manufacturing is simple and cost is low, but mixed color lighting cannot be achieved
Solution Approach 1:
The active layer is divided into multiple quantum well structures with different compositions (InGaN wells with varying Indium content), each emitting at different wavelengths. This segmentation allows a single LED chip to generate multiple color bands simultaneously, resolving the contradiction between manufacturing simplicity and color mixing capability.
Solution Approach 2:
Different regions of the active layer have different material compositions and thicknesses, creating localized emission characteristics. The quantum wells are designed with graded Indium content to produce specific wavelength bands in different zones, enabling color mixing within a single chip while maintaining straightforward manufacturing processes.
2Adaptability or versatility
If multiple LEDs are used to achieve mixed color light, then color temperature adjustment is possible, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Multiple quantum well structures with different emission wavelengths are merged into a single active layer, which is then integrated into one LED chip. This combining approach replaces the need for multiple separate LEDs while maintaining the ability to adjust color temperature through selective excitation of different quantum wells.
Solution Approach 2:
The single LED chip is designed to perform multiple functions: it can emit various color bands, adjust color temperature, and provide mixed color lighting all within one device. The multi-quantum well structure enables this universality by allowing different regions to contribute different wavelengths based on excitation conditions.
3Illumination intensity
If phosphors are used to convert wavelength, then white light can be generated, but efficiency decreases due to Stoke's shift
Solution Approach 1:
The patent extracts the wavelength conversion function entirely by eliminating phosphors from the system. Instead, multiple quantum wells directly emit different wavelengths through electroluminescence, removing the energy loss associated with Stoke's shift while maintaining efficient white light generation.
Solution Approach 2:
The passive phosphor conversion mechanism is replaced with an active electroluminescence mechanism. The quantum wells directly generate the desired wavelengths through electron-hole recombination, substituting the phosphor-based wavelength conversion process and thereby eliminating the associated energy losses.
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 solution enables efficient production of mixed color lighting, reducing production costs and improving efficiency by eliminating the need for phosphors and simplifying manufacturing processes.
Implementation Method 1
the active layer may include a first well layer portion and a second well layer portion... the light emitting diode emits light having a first spectrum including a first peak wavelength and light having a second spectrum including a second peak wavelength
Data Source
AI summary
A lighting apparatus includes a light emitting diode, in which the light emitting diode includes an n-type nitride semiconductor layer, an active layer located on the n-type nitride semiconductor layer, and a p-type nitride semiconductor layer located on the active layer. The light emitting diode emits light that varies from yellow light to white light depending on a driving current.