Phosphor Composition in Light Emitting Devices for Melanopic Control
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Solution Overview
Problem
Existing light emitting devices do not adequately consider the impact of light on human circadian rhythm and visibility, particularly in terms of melanopic ratio and color rendering properties, which are crucial for comfort and visibility similar to natural light.
Innovation Solution
A light emitting device comprising a light emitting element and a fluorescent member with specific phosphors, tailored to achieve a melanopic ratio within certain ranges and correlated color temperatures, using phosphors with defined compositions and content percentages to optimize light emission for comfort and visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional phosphors are used in light emitting devices, then manufacturing simplicity is maintained, but color rendering properties and melanopic ratio are insufficient for comfort and natural light visibility
Solution Approach 1:
The patent employs composite phosphor materials combining multiple phosphor types (e.g., yellow phosphor with 560-580nm peak, red phosphor with 610-650nm peak, green phosphor with 500-540nm peak) to achieve superior color rendering properties and melanopic ratio. This composite approach allows simultaneous optimization of multiple optical parameters that cannot be achieved with single phosphor materials, directly resolving the contradiction between improved reliability and increased complexity.
Solution Approach 2:
The patent systematically adjusts phosphor emission peak wavelengths, full width at half maximum (FWHM) values, and content ratios to optimize the melanopic ratio and color rendering. By changing these parameters within specific ranges (e.g., yellow phosphor FWHM: 80-120nm, red phosphor content: 5-30%), the invention achieves natural light-like visibility and comfort without requiring overly complex multi-phosphor systems.
2Adaptability or versatility
If light emitting devices are designed for general lighting, then broad applicability is achieved, but specific melanopic ratio and circadian rhythm influence are not optimized
Solution Approach 1:
The patent enables dynamic adjustment of the melanopic ratio by varying the phosphor composition ratios and emission characteristics. Different phosphor combinations can be used to achieve different melanopic ratios suitable for different times of day or usage scenarios, allowing the lighting device to adapt to circadian rhythm requirements while maintaining broad applicability across various environments.
Solution Approach 2:
The patent achieves environment-specific optimization by adjusting key parameters such as correlated color temperature (2856K or 6504K), melanopic ratio (0.5-2.0), and phosphor emission peak wavelengths. These parameter changes allow the same device structure to serve multiple usage environments while maintaining controlled melanopic ratio for circadian rhythm influence.
3Use of energy by moving object
If blue light emitting elements are used, then energy efficiency is improved, but impact on circadian rhythm and color rendering accuracy worsen
Solution Approach 1:
The patent converts the potentially harmful blue light emission into a beneficial system by using blue LED excitation to drive phosphors that emit in the green (500-540nm) and red (610-650nm) regions, which are more favorable for circadian rhythm. The blue light is thus transformed into a useful excitation source rather than a harmful output, maintaining energy efficiency while reducing circadian disruption.
Solution Approach 2:
The patent uses composite phosphor materials that absorb blue LED emission and convert it to green and red light with appropriate melanopic content. This composite phosphor system maintains the energy efficiency of blue LED excitation while producing a spectral distribution that better supports circadian rhythm and color rendering, effectively converting the harmful blue light effect into a beneficial multi-wavelength output.
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
The device provides improved color rendering properties and a specific melanopic ratio, promoting comfort and visibility by aligning light emission with natural light conditions, suitable for various environments.
Implementation Method 1
a light emitting device that emits mixed color light by using a light emitting element that emits blue light and a phosphor that emits light when excited by the light from the light emitting element
Data Source
AI summary
To provide a light emitting device having a good color rendering property and a specific melanopic ratio.A light emitting device includes a light emitting element, and a fluorescent member including a phosphor. The light emitting device satisfies any of Condition (A): a correlated color temperature of light emission of the light emitting device is within a range of 4500 K or more and 7500 K or less, a content of a first phosphor is within a range of 29 mass % or more and 90 mass % or less, and a melanopic ratio is within a range of 1.0 or more and 1.4 or less; Condition (B): a correlated color temperature of light emission of the light emitting device is within a range of 2500 K or more and less than 4500 K, a content of a first phosphor is within a range of 25 mass % or more and 90 mass % or less, and a melanopic ratio is within a range of 0.7 or more and 1.1 or less; and Condition (C): a correlated color temperature of light emission of the light emitting device is within a range of 2500 K or more and 3000 K or less, a content of a first phosphor is within a range of 20 mass % or more and 90 mass % or less, and a melanopic ratio is within a range of 0.48 or more and 1.10 or less.