Solid State Lighting Devices with Adjustable Color Point Control
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Solution Overview
Problem
Current solid state lighting devices, such as LEDs, often fail to achieve desirable illumination characteristics like high luminous efficacy and accurate color reproduction, particularly in terms of Color Rendering Index (CRI) and Gamut Area Index (GAI), which are essential for mimicking natural light sources.
Innovation Solution
The development of solid state lighting devices with multiple solid state light emitters and a control circuit that adjusts aggregated emissions to produce a mixture of light with an adjustable color point, specifically targeting coordinates on or near the white body locus in the CIE 1931 Chromaticity Diagram, ensuring high luminous efficacy and optimal color rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LED packages with single emitter and fixed phosphor are used, then device structure is simple, but color rendering index and gamut area index are insufficient
Solution Approach 1:
The patent divides the single LED emitter into multiple separate solid state light emitters, each emitting at different wavelengths (e.g., blue, green, red regions). This segmentation allows independent control and optimization of each emitter's contribution to the overall spectrum, enabling high CRI and GAI values while maintaining reasonable device complexity through modular architecture.
Solution Approach 2:
The patent combines multiple solid state light emitters with different spectral outputs into a single integrated device. By merging emitters that cover different wavelength regions (blue, cyan, green, yellow-green, red), the device achieves a comprehensive spectrum that closely mimics natural light, thereby attaining Class A color rendering with CRI≥95 and GAI≥90.
2Adaptability or versatility
If multiple solid state light emitters with independent control are used, then adjustable color point and high CRI are achieved, but device complexity increases
Solution Approach 1:
The patent implements dynamic control of multiple solid state light emitters through a control circuit that independently adjusts the drive current or duty cycle of each emitter. This dynamic adjustment capability enables real-time modification of the aggregated light spectrum, allowing the color point to be positioned anywhere within a large triangle on the CIE 1931 chromaticity diagram while maintaining Class A color rendering characteristics.
Solution Approach 2:
The patent changes the operational parameters (current, duty cycle, or intensity) of each solid state light emitter to achieve different color points and rendering characteristics. By varying these parameters dynamically, the device can adapt to different lighting requirements while maintaining high CRI and GAI values, effectively managing complexity through software-controlled parameter optimization.
3Measurement precision
If solid state emitters with narrow emission bins are used, then color point precision is improved, but luminous efficacy may be reduced
Solution Approach 1:
The patent applies local quality by selecting solid state light emitters with narrow emission bins (≤10% of CIE chromaticity diagram area) for specific wavelength regions where precision is critical (blue, cyan, green, yellow-green, red). Each emitter's narrow spectral output is strategically positioned to contribute to specific portions of the overall spectrum, achieving precise color point control (within 5-7 MacAdam ellipses of WBL) while maintaining high luminous efficacy through optimized emitter selection and combination.
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 the creation of lighting devices with improved CRI and GAI values, providing more vivid and accurate color representation, thereby enhancing the overall illumination quality and user preference.
Implementation Method 1
Solid state emitters may include lumiphoric materials (also known as lumiphors) that absorb a portion of emissions having a first peak wavelength emitted by the emitter and re-emit light having a second peak wavelength that differs from the first peak wavelength
Data Source
AI summary
A solid state lighting device includes multiple solid state light emitters and a control circuit configured to adjust aggregated emissions to produce a mixture of light having an adjustable color point together with high luminous efficacy, wherein at least one color point is on or near the white body line WBL (line of minimum tint). Adjustment of color point may provide substantially constant 1931 CIE x-values; substantially constant 1931 CIE y-values, or substantially constant distance relative to the blackbody locus (e.g., with variation in CCT of at least 100K for the color points). An adjustable color point may be arranged to transition between one point near the BBL and another point on or near the WBL. An adjustable color point may provide a first color point on or near the WBL and another point having different CCT and luminous flux. Emitters selected solely from discrete bins or subregions of a CIE diagram may be used in combination to yield a point on or near the WBL.