Single-Chip Multi-Band LED With Multi-Quantum Wells for White Light
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) using nitride semiconductors struggle to produce white light efficiently, requiring multiple LEDs or phosphors, which increase costs and reduce efficiency, and are not suitable for visible light communication due to slow frequency response and complexity in manufacturing.
Innovation Solution
A single-chip LED with a novel structure featuring a multi-quantum well active layer and a V-pit generation layer, emitting white light as driving current increases, eliminating the need for multiple LEDs or phosphors and enhancing suitability for visible light communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphors are used to convert wavelength to produce white light, then white light can be generated, but production cost increases and efficiency decreases due to Stoke's shift loss
Solution Approach 1:
The patent removes the phosphor conversion layer from the system entirely. Instead of using phosphors to convert blue light to white light, the invention directly generates white light through a multi-quantum well active layer with different well depths, eliminating the energy loss associated with Stoke's shift in phosphor conversion.
2Illumination intensity
If phosphors are applied on the light emitting diode, then white light can be produced, but the process becomes more complex and phosphor yellowing occurs
Solution Approach 1:
The invention extracts and removes the phosphor application process from the device structure. White light is generated directly in the active layer through controlled electron-hole recombination in multi-quantum wells, eliminating the need for separate phosphor coating, curing, and alignment processes.
3Illumination intensity
If multiple light emitting diodes are used to produce mixed color light, then white light can be achieved, but the manufacturing process becomes complicated
Solution Approach 1:
The patent merges multiple light-emitting functions into a single LED chip. By creating a multi-quantum well active layer with wells of different depths (first, second, and third quantum wells), the device produces multiple wavelengths (blue, cyan, green) simultaneously within one chip, eliminating the need to assemble multiple separate LEDs.
4Illumination intensity
If conventional quantum well structure is used, then light emission occurs, but only single peak monochromatic light is produced
Solution Approach 1:
The patent applies local quality by creating quantum wells with different local properties - specifically, wells of different depths and compositions within the same active layer. The first quantum well has different characteristics than the second and third quantum wells, enabling each region to emit at different wavelengths, thus producing a multi-peak spectrum from a single chip.
5Adaptability or versatility
If general white LED is used for Li-Fi, then visible light communication is possible, but data transmission speed is slow due to frequency response limitation
Solution Approach 1:
The patent employs dynamics by enabling rapid modulation of the multi-peak light emission through direct electrical control of the multi-quantum well structure. Without phosphor conversion delays, the LED can quickly switch between different emission states, achieving high-frequency modulation necessary for fast data transmission in Li-Fi applications.
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 white light without phosphors, reducing production costs and improving data transmission speed in visible light communication applications.
Implementation Method 1
the active layer has a single structure of a multi-quantum well in which a plurality of barrier layers and a plurality of well layers are stacked, and the active layer emits white light
Data Source
AI summary
A 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 active layer has a single structure of a multi-quantum well in which a plurality of barrier layers and a plurality of well layers are stacked, and the active layer emits white light.