Europium-Manganese Silicate Phosphor for LED Color Rendering
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Solution Overview
Problem
White light emitting LED devices that combine a blue light emitting diode with yellow phosphors, such as BOSS or YAG, suffer from inadequate red light emission, leading to low color rendering properties and uneven color distribution, particularly in illumination applications where they are used as alternatives to fluorescent lamps.
Innovation Solution
A europium-manganese-activated alkaline earth magnesium silicate phosphor with a specific chemical composition (Sr2-X-Y-Z-ωBaXMgYMnZEuω)SiO4, where x, y, z, and ω are within defined ranges, is used in combination with ultraviolet to blue light emitting diodes to produce white light with improved color uniformity and high color rendering properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a blue light emitting diode is combined with yellow phosphors (BOSS or YAG), then brightness is improved, but color rendering properties deteriorate due to inadequate red light emission
Solution Approach 1:
The patent employs a composite phosphor system combining multiple phosphor materials with different emission characteristics. Specifically, it uses yellow phosphors (BOSS or YAG) combined with red phosphors to create a composite material that maintains high brightness while adding sufficient red light emission to improve color rendering properties.
Solution Approach 2:
The patent merges multiple phosphor types (yellow and red) into a single lighting system that works in conjunction with the blue light emitting diode. This combination allows the system to achieve both high brightness from the yellow phosphor and improved color rendering from the red phosphor, resolving the contradiction between brightness and color rendering.
2Device complexity
If conventional yellow phosphors are used with blue LEDs, then device simplicity is maintained, but color uniformity deteriorates due to uneven color distribution
Solution Approach 1:
The patent uses composite phosphor materials that integrate multiple emission spectra within a unified structure. This composite approach ensures uniform color distribution while maintaining relative device simplicity, as the mixed phosphors can be applied together as a single layer rather than requiring separate complex optical paths.
Solution Approach 2:
The patent applies different phosphor materials in specific proportions and distributions to achieve uniform color output. By carefully controlling the local composition and ratio of yellow and red phosphors, the system ensures consistent color distribution across the entire emission area while keeping the overall device structure simple.
3Reliability
If multiple phosphor types are added to improve color rendering, then color rendering properties are improved, but device complexity increases
Solution Approach 1:
The patent combines multiple phosphor types (yellow and red) into a single integrated phosphor layer that is applied directly to the blue LED. This merging approach improves color rendering properties by adding red light emission while avoiding the need for separate optical paths or complex multi-component assemblies, thus limiting the increase in device complexity.
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 phosphor emits luminescent components of red, blue, and green, ensuring uniformity and high brightness with minimal color variation, making it suitable for high-quality lighting applications without the need for additional color mixing mechanisms, and is environmentally friendly as it does not contain mercury.
Implementation Method 1
a phosphor that absorbs light emitted by the light emitting diode
Implementation Method 2
a phosphor that absorbs light emitted by the light emitting diode to emit white to yellowish white light
Data Source
AI summary
An LED light emitting device is provided that has high color rendering properties and is excellent color uniformity and, at the same time, can realize even luminescence unattainable by conventional techniques. A phosphor having a composition represented by formula: (Sr2-X-Y-Z-ωBaXMgYMnZEuω)SiO4 wherein x, y, z, and ω are respectively coefficients satisfying 0.1<x<1, 0<y<0.5, 0<z<0.1, y>z, and 0.01<ω<0.2 is provided. The phosphor is used in combination with ultraviolet and blue light emitting diodes having a luminescence peak wavelength of 360 to 470 nm to form an LED light emitting device.