LED Chromaticity Conversion via Built-in Quantum Wells
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Solution Overview
Problem
Conventional light emitting devices, such as LEDs, that use phosphors to produce white light suffer from low optical efficiency, reliability issues due to phosphor degradation, and complex manufacturing processes.
Innovation Solution
Incorporating a built-in conversion material with specific semiconductor structures and dopants on the LED die to produce a secondary emission that combines with the primary emission to achieve white light, eliminating the need for phosphors and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphors are used to produce white light in LED devices, then white light emission is achieved, but optical efficiency decreases and reliability deteriorates due to phosphor degradation
Solution Approach 1:
The patent extracts and eliminates the phosphor component from the LED device, replacing it with a quantum well structure that directly converts blue light to yellow light through radiative recombination of charge carriers, thereby removing the reliability issues associated with phosphor degradation while maintaining white light emission
Solution Approach 2:
The patent changes the physical mechanism from phosphor-based downconversion to quantum well-based radiative recombination, altering the fundamental parameter of light conversion method to achieve both white light emission and improved reliability through enhanced optical efficiency
2Illumination intensity
If phosphors are deposited on LED dies to achieve white light, then chromaticity conversion is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the light conversion function directly into the semiconductor active region by integrating quantum well structures within the LED die itself, eliminating the separate phosphor deposition step and simplifying the manufacturing process while achieving the same chromaticity conversion effect
Solution Approach 2:
The quantum well structure serves multiple functions simultaneously: it acts as the active region for charge carrier injection and recombination, and also performs the chromaticity conversion from blue to yellow light, thereby eliminating the need for separate phosphor materials and deposition processes
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
This approach enhances optical efficiency, increases device reliability, and reduces manufacturing complexity and costs by converting a higher percentage of the primary emission into the secondary emission, while maintaining consistent light output and extending the device's useful life.
Implementation Method 1
a conversion material formed on the second semiconductor material and configured to produce a second emission stimulated by the first emission
Data Source
AI summary
Various embodiments of light emitting devices with built-in chromaticity conversion and associated methods of manufacturing are described herein. In one embodiment, a method for manufacturing a light emitting device includes forming a first semiconductor material, an active region, and a second semiconductor material on a substrate material in sequence, the active region being configured to produce a first emission. A conversion material is then formed on the second semiconductor material. The conversion material has a crystalline structure and is configured to produce a second emission. The method further includes adjusting a characteristic of the conversion material such that a combination of the first and second emission has a chromaticity at least approximating a target chromaticity of the light emitting device.