Wavefront Sensor Glass Substrate Measurement
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Solution Overview
Problem
Existing methods for measuring features on glass-based substrates are limited by the need for extensive calibration, are sensitive to vibrations, and require multiple inspections, which slows down the measurement process and reduces production efficiency.
Innovation Solution
The use of at least one wave front sensor, integrated with an illumination source and a reflector, allows for quick, inline, and quantitative measurement of features on glass-based substrates, reducing the need for recalibration and enabling measurements while the substrate is moving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional inspection techniques (camera with bright-field illumination, oblique illumination, or knife-edge illumination) are used to identify and qualitatively characterize features, then feature location and qualitative characterization can be achieved, but quantitative characterization requires meticulous calibration, extended exposure, multiple exposures, and exposures at several orientations which increases measurement time and complexity
Solution Approach 1:
The patent replaces traditional mechanical/optical inspection systems (cameras with various illumination techniques requiring meticulous calibration and multiple exposures) with a wavefront sensor-based optical path difference measurement system. This substitution enables quantitative characterization of features through direct optical path difference measurements, eliminating the need for extended exposure and multiple exposures while reducing calibration requirements.
Solution Approach 2:
The patent changes the measurement parameter from intensity-based measurements (requiring multiple exposures and orientations) to optical path difference measurements. By measuring the phase information directly through wavefront sensing, the system achieves quantitative feature characterization in a single measurement, significantly reducing measurement time and eliminating the need for extended exposure.
2Reliability
If traditional inspection techniques are used, then feature identification is possible, but the techniques are sensitive to vibrations and require recalibration between measurements
Solution Approach 1:
The patent replaces vibration-sensitive traditional optical inspection systems with a wavefront sensor-based system that measures optical path differences. This substitution makes the measurement process insensitive to vibrations because the relative optical path difference between reference and measurement beams remains stable even during substrate movement, eliminating the need for recalibration between measurements.
Solution Approach 2:
The patent introduces a reference beam as an intermediary that travels a different path than the measurement beam. By comparing the optical path differences between the reference and measurement beams, the system can compensate for vibrations and environmental disturbances, maintaining measurement stability without requiring recalibration.
3Measurement precision
If multiple inspections are performed to achieve accurate measurements, then measurement accuracy can be improved, but production efficiency decreases and processing time increases
Solution Approach 1:
The patent enables continuous measurement by using wavefront sensing that can accurately characterize features in a single pass without requiring multiple inspections. The optical path difference measurement method maintains measurement accuracy while allowing the substrate to move continuously through the inspection system, thereby improving production efficiency and reducing processing time.
Solution Approach 2:
The patent replaces multiple sequential inspection operations with a single wavefront sensor-based measurement system. This substitution achieves the same measurement accuracy that previously required multiple inspections, thereby eliminating idle time between measurements and improving overall production efficiency.
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 enables accurate and vibration-insensitive measurement of features, allowing for faster production processes and reducing downtime due to recalibration needs.
Implementation Method 1
detecting the light transmitted through the target location using at least one wave front sensor
Implementation Method 2
transmitting light through a thickness of the glass-based substrate towards a first major surface of the glass-based substrate
Implementation Method 3
providing at least one wave front sensor and an illumination source in a first region that is opposite a second region comprising a reflector with a measurement plane
Data Source
AI summary
An apparatus can comprise an illumination source and at least one wave front sensor that positioned in a first region. A reflector can be positioned in a second region. A measurement plane can be positioned between the first region and the second region. The reflector can be configured to reflect the light. The at least one wave front sensor can be configured to detect the light. Methods of measuring a feature of a glass-based substrate can comprise emitting light from the illumination source. Methods can comprise transmitting the light through a thickness of the glass-based substrate. Method can comprise transmitting the light through a target location of a first major surface of the glass-based substrate. Methods can comprise detecting the light with the at least one wave front sensor and generating a signal based on the detected light.