Optical Measuring Device for Stage Height Monitoring
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Solution Overview
Problem
Conventional stage measuring devices face challenges in accurately measuring thinning objects due to the risk of damage from excessive pressing force and measurement inaccuracies from grinding particles, especially in environments with high environmental pollution.
Innovation Solution
An optical measuring device employing chromatic confocal distance measurement and optical coherence tomography (OCT) techniques with dual beam guides and spectral broadband light sources, allowing for contactless and robust distance measurement between a support and an edge region of an object, using dual measuring heads and spectrometers to acquire and evaluate reflection spectra for precise stage height monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tactile probes are used to measure stage height, then measurement can be performed in grinding environments, but the probes may damage the edge region of the object due to excessive pressing force
Solution Approach 1:
The patent replaces the mechanical tactile probe system with an optical measurement system. The optical measuring device uses light beams to measure stage height without physical contact, thereby eliminating the risk of probe-induced damage to the edge region while maintaining the ability to operate in grinding environments.
Solution Approach 2:
The patent introduces light as an intermediary medium for measurement. Instead of direct mechanical contact, the optical system uses light beams to interact with the object surface, enabling non-contact measurement that avoids damage while providing sufficient measurement capability in harsh environments.
2Reliability
If tactile probes are used to measure stage height, then measurement can be performed, but measurement inaccuracies occur due to grinding particles on the support surface
Solution Approach 1:
The patent replaces the mechanical probe system with an optical system that is immune to contamination. The optical measurement method uses light reflection and interference patterns that are not affected by grinding particles, allowing accurate measurement even in highly polluted grinding environments where tactile probes fail.
Solution Approach 2:
The patent creates an optical copy or representation of the object surface through light reflection. Instead of direct mechanical contact that is compromised by particles, the system uses reflected light to create interference patterns that accurately represent the surface geometry, enabling precise measurement despite the presence of grinding particles.
3Measurement precision
If pressing force is increased to improve measurement stability, then measurement accuracy improves, but the risk of damage to the edge region increases
Solution Approach 1:
The patent eliminates the pressing force issue by replacing mechanical contact with optical measurement. The optical system measures stage height through light beam interaction with the object surface, requiring no pressing force and thus completely avoiding the trade-off between measurement stability and damage risk.
4Measurement precision
If conventional optical measuring devices are used, then non-contact measurement is achieved, but the devices occupy excessive space and are not robust enough for high environmental pollution
Solution Approach 1:
The patent merges multiple optical components into a compact integrated measuring head. The dual beam guide configuration combines light source, beam splitting, and detection functions in a space-efficient arrangement that maintains non-contact measurement capability while reducing overall device size and improving robustness for harsh environments.
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 provides reliable, accurate, and robust measurement results with high scanning rates, capable of filtering out measurement errors due to dust and aerosols, ensuring precise monitoring of thinning processes even in harsh grinding environments.
Implementation Method 1
the reflected light, or the three partial beams of the light reflected by the surface, are directed together with a second part of the measuring light towards a spatially resolving detector where they form interferences
Implementation Method 2
a chromatic confocal distance measuring technique is understood to mean a method which uses the effect in which lenses for different wave lengths of light have different focal points
Data Source
AI summary
The invention relates to an optical measuring device for acquiring in situ a difference in distance between a support and an edge region of an object to be measured. The optical measuring device has a measuring head with dual beam guide which directs a first measuring beam towards the support and a second measuring beam towards the edge region of the object to be measured. Means are provided for acquiring and forming reflection spectra of the first measuring beam which is directed towards the support and the second measuring beam which is directed towards the edge region of the object to be measured. The measuring device has a multi-channel measuring apparatus with one spectrometer line. An evaluation unit for the reflection spectra for acquiring the stage height between the support and the edge region of the object works together with a spectrometer and a display unit.