Silicate Group Phosphor for High Efficiency and Weather Resistance
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Solution Overview
Problem
Existing phosphors that emit reddish orange light have poor light emission efficiency and weather resistance, making them unsuitable for use in displays and lighting devices, requiring a phosphor that can emit light at high intensity and withstand environmental conditions.
Innovation Solution
A silicate group phosphor represented by the general formula M1 5-x Eu x M2 m M3 n O 2m+(3/2)n+5, where x, m, and n are within specific ranges, incorporating elements like Mg, Ca, Sr, Ba, Si, B, Al, and rare earth elements, which absorbs light in the ultraviolet to visible range and emits reddish orange light with improved intensity and weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If (Sr, Ca)S:Eu group phosphor is used to emit green light, then light emission can be achieved, but weather resistance is poor and light emission efficiency is low
Solution Approach 1:
The patent employs silicate-based composite phosphor materials doped with rare earth elements (Eu, Tb, Dy) to achieve both high weather resistance and efficient light emission. The silicate matrix provides chemical stability and weather resistance, while the rare earth dopants enable efficient photoluminescence conversion, resolving the contradiction between durability and efficiency.
Solution Approach 2:
The patent systematically varies compositional parameters (ratios of SiO2, Al2O3, rare earth oxide content) to optimize both weather resistance and light emission efficiency. By adjusting these parameters within specific ranges, the phosphor achieves simultaneous improvement in both properties rather than sacrificing one for the other.
2Illumination intensity
If mixture ratio of reddish orange phosphor is increased to provide reddish color tone, then color tone is improved, but relative intensity of light emission decreases
Solution Approach 1:
The patent applies local quality by using different phosphor materials with complementary emission characteristics in specific proportions. The silicate-based phosphor with reddish-orange emission is combined with other phosphors to achieve balanced color rendering while maintaining high overall emission intensity, avoiding the energy loss associated with excessive mixing.
Solution Approach 2:
The patent utilizes phosphors with specific emission spectra that can be tuned by compositional adjustments. By selecting phosphors with optimal emission wavelengths and combining them appropriately, the device achieves desirable reddish color tones without sacrificing light emission intensity, as the phosphor conversion efficiency is optimized through compositional control.
3Use of energy by moving object
If phosphor is designed for high light emission intensity, then luminous efficiency is improved, but weather resistance may be compromised
Solution Approach 1:
The patent uses composite phosphor structures where a weather-resistant silicate matrix encapsulates and protects the luminescent rare earth dopants. This composite architecture allows the inner luminescent centers to operate at high efficiency while the outer silicate shell provides protection against environmental degradation, simultaneously achieving both high luminous efficiency and weather resistance.
Solution Approach 2:
The silicate matrix acts as a protective barrier that anticipates and prevents environmental damage to the luminescent centers. By providing this protective cushioning beforehand, the phosphor maintains its high light emission efficiency over time without degradation from moisture, oxygen, or other environmental factors that would otherwise compromise performance.
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 silicate group phosphor achieves high luminous efficiency and excellent weather resistance, enabling the production of light emitting devices that emit reddish orange light with enhanced intensity and color tone control, suitable for various lighting applications.
Implementation Method 1
a phosphor that absorbs light from an excitation light source in proximity to 460 nm and converts the wavelength of the light
Data Source
Figure 1
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AI summary
A light emitting device includes a light emitting element 1 that has a light emission peak wavelength in a range from 300 nm to 530 nm, and a phosphor 2 that absorbs light from the light emitting element 1 and converts the wavelength of the light to emit light with a light emission peak wavelength different from the light emitting element. The phosphor is represented by the general formula M15-xEuxM2mM3nO2m+(3/2)n+5 where x, m and n fall within ranges 0.0001 < x ≤ 0.3, 1.0 ≤ m < 2.5 and 0 < n < 2.5, M1 is at least one element selected from the group consisting of Mg, Ca, Sr, Ba and Zn, M2 is at least one element selected from the group consisting of Si, Ge and Sn, and M3 is at least one element selected from the group consisting of B, Al, Ga, In and rare earth elements.