Lumiphor-Converted Solid State Lighting for Enhanced Perceived Brightness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solid state lighting devices fail to accurately represent perceived brightness in real-world settings, as they primarily focus on lumen output without considering human perception, and struggle to enhance brightness while maintaining sufficient color rendering index (CRI) values.
Innovation Solution
The use of lumiphoric materials with specific spectral peaks, such as cyan, green, amber/orange, or red, in combination with narrow-band red content, to increase melanopic spectral efficiency, along with supplemental electrically activated solid state light emitters, enhances perceived brightness while maintaining CRI values above 70, by optimizing the melanopic/photopic spectral ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional solid state lighting devices focus on lumen output, then brightness is improved, but perceived brightness accuracy deteriorates
Solution Approach 1:
The patent changes the spectral parameters of the light source by incorporating specific lumiphoric materials with defined peak wavelengths (cyan 485-530nm, green 520-560nm, amber 560-590nm, red 600-680nm) and controlling the melanopic/photopic spectral ratio, thereby transforming the light's interaction with human vision to improve perceived brightness accuracy while maintaining lumen output
Solution Approach 2:
The patent introduces lumiphoric materials as intermediary substances that convert blue LED emissions into multiple spectral components (cyan, green, amber, red) with specific melanopic efficiency characteristics, mediating between the blue LED source and human perception to achieve accurate perceived brightness representation
2Illumination intensity
If melanopic spectral efficiency is increased to enhance perceived brightness, then brightness perception is improved, but color rendering index deteriorates
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different spectral components: cyan and green lumiphors primarily contribute to melanopic efficiency and perceived brightness, while amber and red lumiphors are optimized for color rendering, allowing each spectral region to specialize in its strength
Solution Approach 2:
The patent uses composite lumiphor formulations combining multiple materials (e.g., cyan Y3Al5O12:Ce, green Lu3Al5O12:Ce, amber CaAlSiN3:Eu, red CaAlSiN3:Eu) to achieve a spectral power distribution that simultaneously optimizes melanopic spectral ratio for perceived brightness and maintains CRI above 70 through balanced spectral content
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 significantly increases perceived brightness while maintaining high color rendering index values, as demonstrated in booth surveys, with some light sources showing up to 21% perceived brightness gain and achieving CRI values of 90, thus providing improved illumination quality.
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
Implementation Method 2
LEDs are solid-state devices that convert electrical energy to light and generally include one or more active layers of semiconductor material
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A solid state lighting device includes at least one electrically activated solid state light emitter configured to stimulate emissions of first through third lumiphoric materials having peak wavelengths in ranges of from 485 nm to 530 nm, from 575 nm to 612 nm, and from 605 nm to 640 nm, respectively (or subranges thereof defined herein), with the third peak having a full width half maximum value of less than 60 nm. The resulting device generates aggregated emissions having a suitably high color rendering index (e.g., CRI Ra) value (e.g., at least 70), and also having a spectral power distribution with a Melanopic/Photopic ratio within a specified target range as a function of correlated color temperature, thereby providing increased perceived brightness.