Near-Infrared Wavelength Converter for Thermal Spectral Stability
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Solution Overview
Problem
Near-infrared phosphors exhibit significant temperature quenching, leading to a decrease in fluorescence intensity and instability in the spectral distribution of near-infrared light emitting devices, which affects the stabilization time of output light.
Innovation Solution
A near-infrared light emitting device is designed with a combination of visible and near-infrared phosphors, where the temperature quenching of both types is controlled within a predetermined range, ensuring a stable spectral distribution by using specific phosphors like LiGa5O8:Cr3+ near-infrared phosphors with minimal temperature quenching and wide spectral bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a general near-infrared phosphor is used in the wavelength converter, then the device can achieve near-infrared light emission, but the temperature quenching is large causing the near-infrared fluorescence intensity to decrease relative to visible fluorescence intensity, resulting in unstable output light intensity
Solution Approach 1:
The patent applies parameter changes by selecting a near-infrared phosphor with specific fluorescence intensity maintenance ratio parameters. The key parameter is the fluorescence intensity maintenance ratio at 150°C, which is set to 90% or more, significantly higher than general near-infrared phosphors. This parameter selection directly addresses the temperature quenching issue and ensures stable output light intensity across temperature variations.
2Power
If the solid-state light emitting element is turned on, then light emission is achieved, but the phosphor temperature rises causing spectral distribution shape to change and requiring stabilization time
Solution Approach 1:
The patent uses parameter changes by selecting phosphors with specific temperature-dependent fluorescence characteristics. The near-infrared phosphor is chosen to have a fluorescence intensity maintenance ratio of 90% or more at 150°C, while the visible phosphor has a ratio of 85% or more. This parameter selection ensures that the spectral distribution shape remains stable even when phosphor temperature rises during operation, eliminating the need for stabilization time.
3Adaptability or versatility
If a wavelength converter with both visible and near-infrared phosphors is used, then both visible and near-infrared light can be emitted for dual-purpose observation, but the temperature quenching difference between phosphor types causes relative intensity changes
Solution Approach 1:
The patent applies parameter changes by carefully selecting the fluorescence intensity maintenance ratios of both visible and near-infrared phosphors. The near-infrared phosphor is selected with a maintenance ratio of 90% or more at 150°C, and the visible phosphor with 85% or more. This coordinated parameter selection ensures that both phosphor types exhibit similar thermal stability characteristics, maintaining a stable fluorescence intensity ratio and enabling reliable dual-purpose observation without intensity drift.
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 maintains a stable spectral distribution and reduces the intensity change between visible and near-infrared fluorescence components, even with temperature rise, enhancing the reliability and precision of spectroscopic applications.
Implementation Method 1
a solid-state light emitting element
Implementation Method 2
a visible phosphor which emits visible fluorescent light having a maximum fluorescence intensity in a wavelength range of visible light, and a near-infrared phosphor which emits near-infrared fluorescent light having a maximum fluorescence intensity in a wavelength range of near-infrared light
Implementation Method 3
a wavelength converter that includes a visible phosphor which emits visible fluorescent light having a maximum fluorescence intensity in a wavelength range of visible light, and a near-infrared phosphor which emits near-infrared fluorescent light having a maximum fluorescence intensity in a wavelength range of near-infrared light
Data Source
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AI summary
A near-infrared light emitting device (100) is configured to satisfy a relationship of 0.853MVIS ≤ MNIR < 1.147MVIS, the MVIS is a ratio of Imax-VIS-150 to Imax-VIS-30, the Imax-VIS-30 is a maximum fluorescence intensity of a visible fluorescence component when a temperature of a wavelength converter (2) is 30°C, the Imax-VIS-150 is a maximum fluorescence intensity of the visible fluorescence component when a temperature of the wavelength converter (2) is 150°C, the MNIR is a ratio of Imax-NIR-150 to Imax-NIR-30, the Imax-NIR-30 is a maximum fluorescence intensity of a near-infrared fluorescence component when a temperature of the wavelength converter (2) is 30°C, and the Imax-NIR-150 is a maximum fluorescence intensity of the near-infrared fluorescence component when a temperature of the wavelength converter (2) is 150°C.