LED Color Temperature Adjustment via Multi-LED Spectrum and Thermal Control
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Solution Overview
Problem
Existing LED-based white light sources struggle to produce adjustable color temperature with high Color Rendering Index (CRI) without the need for filters, while being efficient, easy to construct, and affordable.
Innovation Solution
Combining warm-white, green, and blue LEDs to create a light source with a continuous spectrum spanning 400 to 700 nm, with a white light point on a selectable Planckian locus location, and using temperature monitoring to calculate and supply the required electrical power for each LED to achieve a CRI greater than 80.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LED assemblies are used to produce white light, then energy efficiency is improved, but color temperature adjustability with high CRI deteriorates
Solution Approach 1:
The invention divides the white light generation into multiple independent LED segments with different spectral characteristics (warm-white LED, cool-white LED, green LED, blue LED). Each LED type contributes specific wavelength ranges to the overall spectrum, allowing independent control of each segment's intensity to achieve both energy efficiency and adjustable color temperature with high CRI.
Solution Approach 2:
The invention combines multiple LED types with complementary spectral outputs to create a composite light source. The warm-white LED provides yellow-green spectrum, cool-white LED provides blue-violet spectrum, green LED fills the green gap, and blue LED provides blue spectrum. This composite approach enables continuous spectrum coverage (400-700nm) and adjustable color temperature while maintaining high energy efficiency and CRI > 80.
2Manufacturing precision
If multiple LED types are combined to achieve continuous spectrum, then CRI is improved, but device complexity increases
Solution Approach 1:
The invention merges multiple LED types (warm-white, cool-white, green, blue) into a single integrated light source assembly. By combining these different LED types in one device, the system achieves continuous spectrum coverage and high CRI (>80) without requiring external filters or complex optical systems, thereby improving color rendering while controlling overall device complexity.
Solution Approach 2:
Each LED type in the assembly serves multiple functions: the warm-white and cool-white LEDs provide both white light with different color temperatures and contribute to the continuous spectrum; the green and blue LEDs fill spectral gaps and enable color temperature adjustment. This multi-functionality allows the system to achieve high CRI and adjustable color temperature without additional components, simplifying the overall device structure.
3Stability of the object's composition
If temperature monitoring and power calculation systems are added, then color temperature stability is improved, but system complexity increases
Solution Approach 1:
The invention incorporates temperature monitoring of the LED assembly and uses this feedback to calculate and adjust the electrical power supplied to each LED type. This closed-loop control system compensates for temperature-induced spectral shifts, maintaining stable color temperature and high CRI while preventing thermal runaway, thereby achieving color temperature stability with controlled system complexity.
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 allows for stable, selectable Planckian locus color temperatures with high CRI, making it suitable for applications like film and video recording, while being efficient and cost-effective, without the need for additional filters.
Implementation Method 1
semiconductor light emitting diodes (LEDs)
Implementation Method 2
light emitting diodes (LEDs)
Implementation Method 3
phosphor
Data Source
AI summary
Assemblies of temperature monitored, semiconductor light emitting diodes (LEDs) are disclosed that produce color temperature adjustable white light sources. Warm-white LEDs are combined with green and blue LEDs to produce light have continuous spectrum spanning the wavelength range of 400 to 700 nm with a white light point located at a selectable Planckian locus location and a color rendering index greater than 80. The circuitry includes LED temperature monitoring used to adjust LEDs spectral and luminosity output. Alternate arrangements combine warm-white LEDs with green, blue and red LEDs; warm-white and cool-white LEDs with green, blue and red LEDs; warm-white and cool-white LEDs with green LEDs; and a warm-white and cool-white LEDs with green-white LEDs.