Rotatable Half-Wave Plate Light Intensity Control for Polarimetry
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Solution Overview
Problem
Light source intensity in light scattering polarimetry systems cannot be effectively controlled to provide optimal light for measuring stress in chemically strengthened glass, leading to inconsistent stress measurements across different types of glass with varying light scattering properties.
Innovation Solution
A method involving a rotatable half-wave plate and a polarizer, aligned to match the polarization direction of an optical compensator, is used to adjust the light beam intensity by rotating the half-wave plate to set the exposure time within a specific range, ensuring consistent stress measurement across different glass types with varying light scattering amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light sensor with fixed integration time is used, then the system structure is simple, but the stress measurement consistency across different glass types deteriorates
Solution Approach 1:
The patent applies the Dynamics principle by making the light source intensity adjustable through a variable attenuator rather than fixed. This allows the system to adapt the light intensity dynamically based on the specific glass type being measured, ensuring optimal measurement conditions for different light scattering properties while maintaining a relatively simple overall system structure.
2Ease of operation
If the light source intensity is not controlled, then the system operation is simple, but the measurement accuracy for different glass types deteriorates
Solution Approach 1:
The patent implements the Self-service principle through an automatic control mechanism that adjusts the light source intensity based on feedback from the detector. The system automatically selects the appropriate light intensity level without requiring manual intervention, thereby maintaining ease of operation while achieving accurate stress measurements across different glass types with varying light scattering properties.
3Productivity
If the exposure time is not optimized, then the measurement process is fast, but the measurement reliability for different glass types deteriorates
Solution Approach 1:
The patent applies the Feedback principle by using the detector to monitor the light intensity and provide feedback to the control mechanism. This feedback loop enables the system to automatically adjust the exposure time and light source intensity to optimal values for each measurement, ensuring reliable stress measurements across different glass types while maintaining efficient measurement speed through automated control.
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
This approach allows for accurate and consistent stress measurement in chemically strengthened glass by optimizing the light intensity for each type, improving the accuracy and reliability of stress characterization.
Implementation Method 1
adjusting the intensity of a light beam using a rotatable half-wave plate and a first polarizer operably disposed between the light source and a rotating light diffuser by aligning the first polarizer with a second polarizer in the optical compensator to have matching polarization directions by rotating the rotatable half-wave plate
Implementation Method 2
The laser light polarization is varied continuously between different polarization states using an optical compensator
Implementation Method 3
Stress in the CS glass causes optical retardation along the light path, with the amount of stress being proportional to the derivative of the optical retardation. The amount of optical retardation can be determined from the stress-induced phase shifts in the detected scattered light intensity distribution
Data Source
AI summary
Systems and methods of performing a stress measurement of a chemically strengthened glass using a light-scattering polarimetry system include adjusting the intensity of a light beam from a light source in an illumination system using a rotatable half-wave plate and a first polarizer operably disposed between the light source and a rotating light diffuser that has a rotation time tR. The first polarizer is aligned with a second polarizer in a downstream optical compensator to have matching polarization directions by rotating the rotatable half-wave plate to a position where the exposure time tE falls within an exposure range tR≤tE. The method also includes performing an exposure using the exposure time tE to obtain the stress measurement. One or both of the half-wave plate and first polarizer can be tilted to avoid deleterious back-reflected light from entering the light source.