LED Lighting Device with Segmented Phosphor Layers
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Solution Overview
Problem
Conventional lighting devices using blue LEDs and mixed fluorescent materials suffer from reduced luminescence efficiency due to green light absorption by red fluorescent materials, limiting the optimization of luminescent efficiency for both components.
Innovation Solution
The use of separate sets of fluorescent material coatings with different dominant wavelengths excited by multiple blue LED sets, allowing for optimal selection of LEDs and coatings to achieve maximum luminescence efficiency and the ability to emit white light with varying color temperatures based on demand and environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a mixed fluorescent material coating is used on a blue LED, then the device structure is simple, but the green light emitted is reabsorbed by the red fluorescent material causing reduced luminescence efficiency
Solution Approach 1:
The invention divides the single mixed fluorescent material coating into separate fluorescent material layers, each with specific wavelength ranges. The first fluorescent material layer emits yellow-green light (520-560nm) and the second fluorescent material layer emits red light (600-650nm), preventing the green light absorption problem that occurs in mixed coatings.
Solution Approach 2:
The invention applies different fluorescent materials with specific spectral characteristics to different regions/layers. Each fluorescent material layer is optimized for its specific wavelength range, with the first layer targeting yellow-green and the second layer targeting red, allowing each material to operate in its optimal performance range without interference.
2Loss of energy
If separate fluorescent material layers are coated on the same blue LED, then the green light absorption problem is solved, but the luminescent efficiency cannot be optimized due to mutual influence between layers
Solution Approach 1:
The invention segments the LED system into multiple independent LED units, each with its own fluorescent material layers. This allows each LED-fluorescent material combination to be independently optimized for maximum luminescent efficiency without mutual interference between different fluorescent layers on the same LED.
Solution Approach 2:
The invention transitions from a single-LED vertical stacking approach to a multi-LED spatial arrangement. Multiple blue LEDs are arranged in an array, with each LED having its own fluorescent material layers, effectively moving the solution from one dimension (vertical layers on one LED) to another dimension (spatial distribution across multiple LEDs).
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 enhances luminescence efficiency and allows for the production of white light with different color temperatures, improving the overall performance of the lighting device.
Implementation Method 1
a plurality of sets of phosphor layers respectively coated on the plurality of LED sets... At least one of the plurality of sets of phosphor layers has a dominant wavelength ranging from 500 nm to 580 nm, and at least another one of the plurality of sets of phosphor layers has a dominant wavelength ranging from 590 nm to 650 nm
Data Source
AI summary
A lighting device comprising LEDs with phosphor layers includes a plurality of LED sets which can emit light with a peak emission wavelength between 360 nm and 490 nm; and a plurality of sets of phosphor layers covering the corresponding LED sets among the plurality of LED sets. At least two of the plurality of LED sets respectively have peak emission wavelength different from each other. The dominant fluorescence wavelength of at least one of the plurality of sets of phosphor layers ranges from 500 nm to 580 nm, and the dominant fluorescence wavelength of at least one of the other sets of phosphor layers ranges from 590 nm to 650 nm.