LED Metamer SPD Adjustment for Brightness and Color Rendering
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Solution Overview
Problem
Current lighting technologies fail to effectively improve color rendition, contrast, and perceived brightness beyond what is described by correlated color temperature (CCT) and color rendering index (CRI, as they do not consider the complexities of spectral power distribution (SPD) and its impact on human perception.
Innovation Solution
The method involves creating a lighting source with a desired CCT and adjusting the blue light component by selecting metamers that match existing light sources, either by measurement, lookup, or mathematical calculation, to enhance SPD and improve perceived brightness and visual acuity, while maintaining the original CCT and color quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If higher CCT light (above 3500K) with more blue light is used, then visual acuity and perceived brightness are improved, but color rendering quality deteriorates
Solution Approach 1:
The patent changes the spectral power distribution parameters of the light source by combining multiple LEDs with different SPD characteristics. Specifically, it adjusts the relative intensities of blue, green, and red LEDs along with their phosphor converters to achieve desired CCT and CRI values independently, resolving the trade-off between brightness and color rendering
Solution Approach 2:
The invention uses composite light sources combining multiple LED types (blue LED with phosphor, green LED with phosphor, red LED with phosphor) to create a composite spectral output. This composite approach allows simultaneous optimization of visual acuity (through blue content) and color rendering (through balanced spectral distribution)
2Ease of operation
If traditional lighting metrics (CCT and CRI) are used to characterize light sources, then general color quality is described, but specific wavelength prominence and metamerism effects are not captured
Solution Approach 1:
The patent segments the spectral power distribution into distinct wavelength regions (blue, green, red) and characterizes each region separately using multiple parameters beyond just CCT and CRI. This segmentation captures metamerism effects and specific wavelength prominence while maintaining practical selection guidance
Solution Approach 2:
The invention adds dimensional complexity to light characterization by introducing multiple SPD parameters beyond the traditional single CCT and CRI values. This multi-dimensional characterization captures the full spectral information needed to describe metamerism and wavelength-specific effects
3Power
If lumen output is increased to improve lighting effectiveness, then total light quantity increases, but perceived brightness and visual acuity may not improve proportionally
Solution Approach 1:
The patent changes the spectral composition parameters rather than simply increasing total lumen output. By optimizing the SPD to include appropriate blue wavelength content and balanced color distribution, the invention improves perceived brightness and visual acuity more efficiently than brute-force lumen increases
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 results in improved lighting that enhances color rendition, contrast, and perceived brightness by optimizing the spectral content of light sources, leading to better visual acuity and energy efficiency without altering the color temperature or overall appearance.
Implementation Method 1
using LEDs to provide light with desirable spectral power distributions
Implementation Method 2
selecting one or more types, models, or bins of white LEDs having specific SPDs
Data Source
AI summary
Methods and systems for illuminating areas or objects in areas by manipulating the spectral power distributions (SPDs) of light sources. In one aspect, light of a given desired correlated color temperature (CCT), white in one example, is adjusted by a metamer to a different SPD designed to produce improved perceived brightness by observers. This retains the desired CCT but can allow for such things as reduced number of light fixtures or light sources, less energy, and/or longer effective light source lives for the same perceived brightness of conventional lightings. In another aspect, composite SPD regardless of CCT can be manipulated for other benefits such as highlighting portions of or objects in the area, or improving lighting performance for such things as weather conditions (e.g. snow or fog) or ambient conditions (e.g. twilight).