Quantum Dot Wavelength Converting Member for Full Spectrum Light
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Solution Overview
Problem
Current light sources, including incandescent and LED-based solutions, fail to produce a continuous full-spectrum lighting with smooth intensity across all visible wavelengths, leading to spiked or dipped spectra, which affects color perception, energy efficiency, and application effectiveness.
Innovation Solution
A light emitting arrangement using a solid state light source and a pixilated wavelength converting member comprising multiple domains of quantum dots, each with narrow emission spectra, arranged to avoid re-absorption and provide a continuous spectrum that closely resembles black body emission, potentially combined with broad band emitting phosphors to fill spectral gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphor-converted LEDs are used to convert blue light to yellow/orange/red light, then white light with desirable CCT and CRI can be obtained, but the spectrum shows peaked distribution with large dips and cannot achieve full spectrum lighting
Solution Approach 1:
The patent divides the wavelength conversion function into multiple segments by using different quantum dot domains with narrow emission spectra at different wavelengths (violet, blue, cyan, green, yellow-green, yellow, orange, red) instead of using single broad-band phosphors. This segmentation allows each domain to contribute to specific spectral regions, filling gaps and creating a continuous full-spectrum output.
Solution Approach 2:
The patent uses composite quantum dot structures with core-shell configurations (e.g., CdSe core with ZnS shell) and combines multiple quantum dot materials with different emission wavelengths in a single wavelength converting member. This composite approach enables precise spectral control and continuous emission across the visible range while maintaining high color purity.
2Illumination intensity
If multiple direct LEDs emitting different colors are used to achieve desirable CCT and CRI, then color performance can be improved, but the spectrum becomes very peaked with large dips and each LED requires different driving currents
Solution Approach 1:
The patent uses a single solid state light source (blue or UV LED) that serves multiple functions by exciting different quantum dot domains to emit at various wavelengths. This universal approach eliminates the need for multiple separate LED drivers while achieving full-spectrum coverage through the wavelength conversion properties of quantum dots with narrow emission spectra.
3Illumination intensity
If conventional broad band phosphors are used for wavelength conversion, then white light can be produced, but re-absorption of secondary light occurs and it becomes difficult to achieve fine tuning of desired spectrum
Solution Approach 1:
The patent assigns specific wavelength conversion functions to different spatial domains within the wavelength converting member, where each domain contains quantum dots optimized for a specific emission wavelength range. This local quality approach ensures that secondary light emitted in one domain does not overlap with absorption bands of adjacent domains, minimizing re-absorption losses and enabling precise spectral tuning.
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 achieves a continuous spectrum with minimal dips, maintaining intensity within 20% of black body emission, enhancing color rendering and energy efficiency, suitable for various applications including general illumination and light therapy.
Implementation Method 1
a wavelength converting member (102) comprising a plurality of domains (102a-h) having different wavelength conversion properties
Implementation Method 2
a solid state light source (101) for emitting primary light
Data Source
Figure 1a~2
Figure 3~4
Figure 5~6b
AI summary
A light emitting arrangement is provided, comprising: - a solid state light source (101) adapted to emit primary light (L1); and - a wavelength converting member (102) comprising a plurality of wavelength converting domains (102a, 102b, 102c, etc) for converting primary light into secondary light (L2), each wavelength converting domain thereby providing a sub-range of the total light output spectrum, wherein at least some of said wavelength converting domains are arranged as an array and comprise quantum dots, wherein different wavelength converting domains comprise quantum dots having different secondary light emission ranges providing different sub-ranges of the total light output spectrum, and wherein a sub-range provided by each wavelength converting domain overlaps or is contiguous with at least one other sub-range provided by another wavelength converting domain. By arranging materials having different wavelength conversion properties in different domains, preferably in a plane, re-absorption of secondary emission can be avoided.