Phosphor Point Source Illumination Spectrum Stabilization
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Solution Overview
Problem
High-intensity light sources used in precision measurement instruments, such as chromatic point sensors, face issues with phosphor output variations affecting the illumination spectrum, leading to instability and inaccuracies in measurements.
Innovation Solution
A system and method that utilize section contribution characteristic data to compensate for phosphor output variations by controlling the excitation energy across different sections of a phosphor point source element, ensuring a stable and predictable illumination spectrum through physical or computational means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a Xenon arc lamp is used as a high intensity broadband light source, then sufficient energy and good S/N ratio are obtained, but arc spatial stability and lifetime are insufficient
Solution Approach 1:
The patent replaces the mechanical/electrical arc discharge system with a photoluminescence-based system. An excitation light source (laser or LED) pumps phosphor material that converts the excitation energy to broadband emission, eliminating arc instability while maintaining high intensity output.
Solution Approach 2:
The patent changes the operating parameters by using pulsed excitation instead of continuous arc discharge. The phosphor material is excited in controlled pulses, allowing precise control of emission intensity and duration, improving both stability and lifetime compared to continuous arc operation.
2Illumination intensity
If a Xenon arc lamp is used for high intensity output, then sufficient brightness is achieved, but modulation rate capability is insufficient
Solution Approach 1:
The patent employs periodic pulsed excitation of the phosphor material instead of continuous arc operation. The excitation light source is modulated at high frequencies, enabling the phosphor to emit light in controlled pulses that can be rapidly modulated to achieve high measurement rates while maintaining peak brightness.
3Reliability
If phosphor material is used to generate broadband light, then long lifetime and high modulation rates are achieved, but phosphor output variations affect illumination spectrum stability
Solution Approach 1:
The patent divides the phosphor emission into multiple wavelength bands, each detected by separate detector elements. By independently characterizing and correcting the output of each wavelength band, the system compensates for phosphor variations and achieves stable spectral output despite inherent phosphor material inconsistencies.
Solution Approach 2:
The patent implements a feedback mechanism where the actual spectral output is measured and used to correct for phosphor variations. The system characterizes the phosphor's wavelength intensity profile and uses this information to compensate for output variations, ensuring stable illumination spectrum over time and across different phosphor batches.
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 significantly reduces unwanted variations in the illumination spectrum, providing a more accurate and stable measurement output, enhancing the performance of high-intensity light sources in precision measurement instruments.
Implementation Method 1
a phosphor point source element comprising phosphor material along a circular operational track which is rotated about an axis, the phosphor material along the circular operational track outputting illumination light in response to excitation energy
Implementation Method 2
an optical element having axial chromatic aberration, also referred to as axial or longitudinal chromatic dispersion, may be used to focus a broadband light source such that the axial distance to the focus varies with the wavelength
Data Source
AI summary
A system and method are provided for utilizing section contribution characteristic data to achieve accurate measurements by compensating for unwanted phosphor output variations that occur at specific sections of phosphor on a rotating high intensity phosphor point source element. Phosphor grain size, density, blend homogeneity, or illumination gap variations may cause the unwanted variations. Based on the section contribution characteristics, excitation energy compensation may provide a stable output illumination spectrum or computational compensation may correct measurements for effects arising from predictable output illumination spectrum variations. The section contribution characteristic data may comprise section wavelength intensity profile data and/or section efficiency data, in various embodiments. In some embodiments, the sections may be on the order of the size of the phosphor grains and may be characterized and compensated. The sections may include phosphor blends, or distinct phosphor types, in various embodiments.