Tunable Multi-Channel LED White Light for High CRI
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Solution Overview
Problem
Existing LED lamps struggle to provide white light across a range of correlated color temperatures (CCT) with high efficiency, luminous flux, and good color rendering index (CRI), particularly due to gaps in spectral power distribution and limited tunability.
Innovation Solution
A method involving multiple LED strings with specific peak wavelengths and luminescent materials to produce white light by combining light through luminophoric mediums, achieving a predefined path near the black body locus in the 1931 CIE Chromaticity Diagram, with high CRI and tunable CCT values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple LEDs of different colors are combined to produce white light, then the luminous flux and efficiency are improved, but the color rendering index deteriorates due to gaps in spectral power distribution
Solution Approach 1:
The patent divides the white light generation into multiple independent LED strings, each emitting at specific peak wavelengths (405-470nm blue, 485-520nm cyan, 530-560nm green, 570-590nm yellow, 610-650nm red). Each string can be independently controlled to fill spectral gaps, thereby improving both luminous flux and color rendering index simultaneously
Solution Approach 2:
The patent combines multiple LED types with different spectral characteristics into a composite lighting system. By integrating LEDs across the entire visible spectrum (405-650nm), the system creates a composite light output that fills spectral gaps and achieves high CRI while maintaining high luminous flux
2Adaptability or versatility
If the drive currents of LEDs are adjusted to tune CCT values, then the adaptability is improved, but the color stability deteriorates
Solution Approach 1:
The patent implements dynamic control of multiple LED strings with independently adjustable drive currents. This allows continuous tuning of CCT across a wide range (2000K-20000K) while maintaining color stability through coordinated adjustment of all LED strings to stay near the black body locus
Solution Approach 2:
The patent changes the operating parameters (drive currents) of each LED string to achieve different CCT values. By systematically varying the current ratios among the five LED strings with peak wavelengths at 405-470nm, 485-520nm, 530-560nm, 570-590nm, and 610-650nm, the system achieves tunable CCT while maintaining color rendering quality
3Reliability
If a broad spectral power distribution is achieved to improve CRI, then the color rendering is improved, but the efficiency deteriorates due to broader wavelength range
Solution Approach 1:
The patent applies local quality by concentrating LED emissions at five specific peak wavelength regions (405-470nm, 485-520nm, 530-560nm, 570-590nm, 610-650nm) rather than using a continuous broad spectrum. This targeted approach fills spectral gaps for high CRI while maintaining high efficiency by avoiding energy distribution across the entire visible range
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
Generates white light within a narrow MacAdam ellipse around the black body locus with CCT between 1800K and 10000K, achieving CRI values greater than 80 and tunable color stability across a wide range.
Implementation Method 1
semiconductor light emitting devices such as light emitting diodes (LEDs)
Implementation Method 2
Most LEDs are substantially monochromatic light sources that appear to emit light having a single color
Implementation Method 3
White light may also be produced by utilizing one or more luminescent materials such as phosphors to convert some of the light emitted by one or more LEDs to light of one or more other colors
Data Source
AI summary
A system for generating white light comprising a plurality of channels to generate light with color points that fall within blue, yellow/green, red, and cyan color ranges, with each channel being driven with a separately controllable drive current to tune the generated light output.