Chromatic Point Sensor Dynamic Intensity Profile Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Chromatic point sensors experience measurement variations due to changes in signal intensity and detector voltage drifts, leading to inconsistent and inaccurate measurements, particularly due to non-uniform wavelength response and temperature-related issues.
Innovation Solution
The solution involves dynamically selecting and limiting a distance-indicating subset of profile data based on a peak position index coordinate, using index-specific data-limiting parameters to compensate for signal intensity and voltage drifts, ensuring that measurement data is comparable to calibration data, thereby improving measurement accuracy and consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all profile data pixels are used for measurement, then measurement coverage is maximized, but measurement precision deteriorates due to non-uniform wavelength response and signal intensity variations
Solution Approach 1:
The profile data is segmented into multiple subsets based on pixel intensity thresholds. Only pixels within a specific intensity range (above a lower threshold and below an upper threshold) are selected for measurement, excluding saturated and noisy regions. This segmentation improves measurement precision by focusing on the most reliable data portions.
Solution Approach 2:
Different regions of the profile data are treated with different quality weights. The selection process identifies and prioritizes pixels with optimal signal characteristics (moderate intensity values) while excluding regions with poor quality (saturated high intensity or noisy low intensity). This local quality assessment enhances overall measurement precision.
2Measurement precision
If signal intensity varies due to temperature drifts, then measurement adaptability is reduced, but using dynamic compensation increases measurement accuracy
Solution Approach 1:
The system dynamically adjusts measurement parameters (pixel intensity thresholds, subset selection criteria) based on the actual signal characteristics observed during measurement. By adapting the data selection parameters to match the current operating conditions and wavelength response, the system maintains high measurement repeatability despite temperature variations and drifts.
3Measurement precision
If the entire intensity profile is analyzed, then measurement range is maximized, but measurement accuracy deteriorates due to non-uniform detector response
Solution Approach 1:
The system extracts and uses only the most reliable portion of the intensity profile data by applying intensity threshold filters. Pixels with intensities within the optimal range are extracted for measurement, while saturated and noisy pixels are excluded. This extraction improves position measurement accuracy by eliminating problematic data points.
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 enhances the repeatability and accuracy of chromatic point sensor measurements, achieving submicron-level precision over a 300 micron range with improved robustness and reduced errors, supporting high measurement rates while maintaining data similarity to calibration data.
Implementation Method 1
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
Implementation Method 2
A spectrometer type detector measures the signal level for each wavelength, in order to determine the surface height
Data Source
AI summary
In a chromatic point sensor, distance measurements are based on a distance-indicating subset of intensity profile data, which is selected in a manner that varies with a determined peak position index coordinate (PPIC) of the profile data. The PPIC indexes the position a profile data peak. For profile data having a particular PPIC, the distance-indicating subset of the profile data is selected based on particular index-specific data-limiting parameters that are indexed with that same particular PPIC. In various embodiments, each set of index-specific data-limiting parameters indexed with a particular PPIC characterizes a distance-indicating subset of data that was used during distance calibration operations corresponding to profile data having that PPIC. Distance-indicating subsets of data may be compensated to be similar to a corresponding distance-indicating subset of data that was used during calibration operations, regardless of overall intensity variations and detector bias signal level variations.