Tunable LED Light Source with Wavelength-Dependent Phosphor
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Solution Overview
Problem
Current lighting systems with multiple LEDs and phosphors struggle to efficiently and flexibly adjust color temperature and color rendition, limiting their adaptability and performance.
Innovation Solution
The implementation of a lighting system with multiple LEDs of different emission wavelengths and a wavelength converting element, such as phosphors, where the absorption strength varies with wavelength, allowing for tunable emission spectra by adjusting the peak wavelengths of LEDs and the absorption properties of phosphors to alter the color temperature of the emitted light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple LEDs with different emission wavelengths and phosphors are used to achieve tunable color temperature, then the adaptability and flexibility of the lighting system is improved, but the device complexity increases
Solution Approach 1:
The patent applies multi-functionality by using a single phosphor material that exhibits wavelength-dependent absorption characteristics. This phosphor simultaneously converts wavelengths from multiple different LEDs (e.g., 450nm, 480nm, 530nm), enabling the system to achieve tunable color temperature without requiring separate phosphor layers for each LED wavelength, thus reducing overall device complexity while maintaining adaptability.
Solution Approach 2:
The invention utilizes parameter changes by exploiting the absorption spectrum characteristics of the phosphor material. By selecting a phosphor with specific absorption properties that vary across different wavelengths, the system can control which LED wavelengths are converted to other wavelengths, enabling continuous tuning of the emission spectrum and correlated color temperature through simple adjustments in LED drive ratios rather than complex physical reconfiguration.
2Manufacturing precision
If the absorption strength of phosphor varies with wavelength to enable spectrum tuning, then the color rendering index is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by utilizing the inherent wavelength-dependent absorption property of the phosphor material. Different regions of the phosphor's absorption spectrum are selectively engaged by different LED wavelengths, allowing each LED-phosphor interaction to be optimized locally for its specific wavelength range. This enables precise control over the conversion efficiency of each wavelength without requiring uniform properties across the entire phosphor layer, simplifying manufacturing while achieving high spectral control precision.
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 enables continuous tuning of the correlated color temperature and high color rendering index, improving the flexibility and performance of the lighting system by varying the ratio of light output from different LEDs and phosphors.
Implementation Method 1
White LEDs include one or more photo-luminescent materials such as phosphors, which absorb a portion of the radiation emitted by the LED and re-emit radiation of a different color (wavelength)
Implementation Method 2
The phosphor material 42 absorbs a portion of the blue light 30 and in response emits light 44 of a different color typically yellow-green in color
Data Source
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AI summary
A lighting system according to embodiments of the invention includes first and second light emitting diodes. The first and second light emitting diodes have different peak wavelengths and emit light of the same color. The system further includes a third light emitting diode that emits light of a different color from the first and second light emitting diodes. A wavelength converting element is disposed in a path of light emitted by the first and second light emitting diodes.