Prism-Coupling Mode Line Tilt Compensation for Stress Analysis
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Solution Overview
Problem
Prism-coupling systems used to characterize stress-related characteristics of ion-exchange (IOX) articles suffer from imperfect mode line formation, resulting in reduced contrast and tilt, leading to inaccuracies in estimating stress-related properties.
Innovation Solution
A method involving a weighted fit to the 2D digital mode spectrum is employed to accurately determine the tilt of mode lines, allowing for tilt compensation and improved estimation of stress-related characteristics by adjusting the measurement system to reduce or eliminate tilt, thereby enhancing the accuracy of stress profile calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prism-coupling systems are used to measure mode spectra, then stress-related characteristics can be characterized, but mode line tilt and reduced contrast occur leading to measurement errors
Solution Approach 1:
The patent applies preliminary action by performing a weighted fit to the 2D digital mode spectrum to accurately determine mode line tilt angles before conducting stress characterization measurements. This preliminary tilt determination and compensation step is executed first to establish accurate mode line positions, ensuring that subsequent stress measurements are not compromised by tilt-induced errors. The system pre-calculates the tilt angle using intensity transitions and applies compensation transformations to correct the mode spectrum data before analysis.
2Productivity
If traditional mode spectrum analysis is used, then stress characteristics can be estimated, but tilt in mode lines causes inaccuracies in position determination
Solution Approach 1:
The patent implements feedback by using the determined mode line tilt angle to compensate and correct the mode spectrum data. The system measures the tilt through intensity transition analysis, then feeds this tilt information back into the measurement process by applying compensation transformations. This closed-loop approach ensures that tilt-induced errors are continuously corrected, maintaining high measurement precision in stress profile estimation while preserving productive stress characterization capability.
Solution Approach 2:
The patent applies parameter changes by transforming the mode spectrum data using the determined tilt angle as a correction parameter. The system changes the orientation parameter of the mode lines through mathematical transformation to eliminate tilt effects. By adjusting the angular parameter of mode line positions based on the calculated tilt angle, the system corrects positional inaccuracies while maintaining the ability to extract stress characteristics from the corrected spectrum.
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 weighted fit method provides a more accurate estimation of stress-related characteristics by compensating for mode line tilt, leading to improved precision in determining properties like stress profile, knee stress, center tension, and refractive index profiles in IOX articles.
Implementation Method 1
using a prism-coupling system, illuminating the IOX article through a coupling prism to generate transverse magnetic (TM) and transverse electric (TE) guided modes in the waveguide region
Implementation Method 2
The IOX region defines within the matrix a refractive index profile... The refractive index profile can also define in the glass-based article an optical waveguide that supports a number m of guided modes
Data Source
AI summary
The prism-coupling systems and methods include using a prism-coupling system to collect a 2D digital mode spectrum of an IOX article. The mode line and critical angle positions and orientations are found by performing a weighted fit to mode line and critical angle images and are used to define a compensated mode spectrum. If mode line tilt is found, it is removed from the 2D digital mode spectrum to define the compensated mode spectrum. The compensated mode spectrum is then processed using techniques known in the art to provide a more accurate estimate of stress-related characteristics of the IOX sample versus using the uncompensated mode spectrum. Derivative-based methods of accurately establishing positions of intensity transitions in a mode spectrum of an IOX sample using a derivative spectrum and curve fitting are also disclosed.