Mn4+ Activated Fluoride Phosphors for High CRI White LEDs
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Solution Overview
Problem
Current white LED lighting systems using blue emitting chips and yellow phosphors have excessive yellow emission, which reduces the color gamut and luminous efficacy, and are not suitable for applications requiring high color rendering index (CRI) and correlated color temperature (CCT) above 5000K without yellow phosphors.
Innovation Solution
Incorporating a red line-emitting phosphor with a peak emission wavelength between 610 and 650 nm, along with a green emitting phosphor and a blue or near-UV emitting LED chip, to produce white light with improved luminous efficacy and CRI, using complex fluoride phosphors activated with Mn4+ as the red line-emitting phosphor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If yellow phosphors are used in white LED lighting systems, then the luminous output is improved, but the color gamut is reduced and excessive yellow emission occurs
Solution Approach 1:
The patent removes yellow phosphors from the lighting system and replaces them with red line-emitting phosphors having peak emission wavelengths between 610-650 nm. This extraction of the problematic yellow emission component while maintaining luminous output through alternative phosphor materials directly resolves the contradiction between luminous efficacy and color gamut.
2Use of energy by moving object
If yellow phosphors are used to achieve high luminous output, then the luminous efficacy is improved, but excessive yellow emission reduces color rendering quality
Solution Approach 1:
The patent converts the harmful excessive yellow emission into beneficial red line emission by using red phosphors with peak wavelengths between 610-650 nm. This transformation maintains the high luminous efficacy while eliminating the harmful yellow emission that degrades color rendering, effectively turning the problem into a solution.
3Illumination intensity
If yellow phosphors are used in LED systems, then the luminous output is maintained, but the system is not suitable for applications requiring CRI above 5000K
Solution Approach 1:
The patent changes the emission wavelength parameter of the phosphor material from yellow (560-580 nm) to red line emission (610-650 nm). This parameter change enables the system to achieve both high luminous output and suitability for high CRI and CCT applications above 5000K, expanding the adaptability to different application requirements.
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 solution achieves high luminous efficacy and CRI values above 280 lm/W at CCTs greater than 5000K with minimal yellow emission, enhancing the color gamut and meeting the requirements for backlighting applications.
Implementation Method 1
A phosphor is a luminescent material that absorbs radiation energy in a portion of the electromagnetic spectrum and emits energy in another portion of the electromagnetic spectrum
Implementation Method 2
complex fluoride phosphors activated with Mn4+ as the red line-emitting phosphor
Implementation Method 3
a green emitting phosphor having a peak emission wavelength between 510 and 550 nm
Data Source
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Figure 5
AI summary
Light emitting apparatuses including backlights having a light source and a phosphor material including a complex fluoride phosphor activated with Mn4+, which may include at least one of (A) A2[MF5]Mn4+, (B) A3[MF6]Mn4+,; (C) Zn2[MF7];Mn4+; (D) A[In2F7]:Mn4+; (E) A2[MF6]:Mn4+; (F) E[MF6]:Mn4+; (G) Bao.65Zro.35F2.7o:Mn4+;or (H) A3[ZrF7]:Mn4+.