Broadband LED Lamp Multi-Quantum Well White Light
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED lamps with red, green, and blue LEDs have narrow spectral power distributions, leading to poor color rendering due to limited spectral coverage, resulting in objects not appearing naturally illuminated.
Innovation Solution
The use of broadband LED chips with multi-quantum well active regions, featuring alternating active and barrier layers with varying stoichiometries, to emit light over broader wavelength ranges, combining to provide white light with improved color rendering without the need for phosphor conversion materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional single-color LED chips are used, then the device structure is simple, but the spectral distribution is narrow leading to poor color rendering
Solution Approach 1:
The patent divides the single LED chip into multiple independent light emitting regions with different bandgaps within the active region. Each region emits light at a different wavelength, creating a segmented spectral output that combines to form a broad spectrum comparable to incandescent bulbs, thereby improving color rendering without requiring multiple separate LED chips.
Solution Approach 2:
The patent employs a multi-layer epitaxial structure with different semiconductor materials (e.g., AlGaInP, InGaN, GaN) having different bandgaps stacked within the active region. This composite material approach enables each layer to emit at different wavelengths, collectively producing a broad spectral distribution that achieves high CRI while maintaining a single chip structure.
2Illumination intensity
If multiple single-color LED chips are combined to broaden spectrum, then the spectral coverage improves, but the device complexity increases
Solution Approach 1:
The patent merges multiple light emitting regions with different bandgaps into a single integrated active region of one LED chip. This consolidation achieves the spectral broadening effect of multiple separate LEDs while eliminating the complexity of assembling, aligning, and driving multiple independent chips, thereby simplifying the overall device structure.
Solution Approach 2:
The single LED chip is designed to perform multiple functions simultaneously: it emits multiple wavelengths (blue, cyan, green, yellow, red) from a single device structure. This multi-functionality eliminates the need for separate LED chips for each wavelength, reducing device complexity while maintaining broad spectral coverage for high CRI white light generation.
3Illumination intensity
If phosphor conversion materials are used to generate white light, then the spectral coverage improves, but energy efficiency decreases due to wavelength conversion losses
Solution Approach 1:
The patent extracts the wavelength conversion function by replacing phosphor materials with direct light emitting regions of different bandgaps. Instead of converting blue LED light through phosphor down-conversion (which incurs energy losses), the invention directly generates multiple wavelengths through electroluminescence in different semiconductor layers, eliminating phosphor-related energy losses and improving overall energy efficiency.
Solution Approach 2:
The patent substitutes the phosphor conversion mechanism (optical absorption and re-emission) with direct electroluminescence emission from multiple semiconductor regions. This replacement eliminates the intermediate conversion step that causes energy loss, achieving broader spectral distribution through direct emission rather than wavelength transformation, thereby improving energy 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
This approach results in high-CRI white light output comparable to incandescent bulbs, with enhanced energy efficiency and broader spectral distribution, improving the natural appearance of illuminated objects.
Implementation Method 1
The radiative recombination of electrons and holes within the active region generates light
Implementation Method 2
Light emitting diodes and laser diodes are well known solid state lighting elements capable of generating light upon application of a sufficient current
Data Source
Figure 1A~1C
Figure 1B
Figure 2A~2C
AI summary
A multi-chip light emitting device (LED) lamp for providing white light includes first and second broadband LED chips. The first LED chip includes a multi-quantum well active region having a first plurality of alternating active and barrier layers. The first plurality of active layers respectively include different relative concentrations of at least two elements of a first semiconductor compound, and are respectively configured to emit light of a plurality of different emission wavelengths over a first wavelength range. The second LED chip includes a multi-quantum well active region having a second plurality of alternating active and barrier layers. The second plurality of active layers respectively include different relative concentrations of at least two elements of a second semiconductor compound, and are respectively configured to emit light of a plurality of different emission wavelengths over a second wavelength range including wavelengths greater than those of the first wavelength range. The light emitted by the first and second LED chips combines to provide white light. Related devices are also discussed.