Combined Workpiece Holder Calibration Profile for Precision Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surface profile measurement systems face challenges in achieving high accuracy and reliability due to environmental instabilities and systematic or dynamic misalignments, which affect the precision of measurements at sub-micron or nanometer levels, especially in applications requiring precise optical performance.
Innovation Solution
A combined workpiece holder and calibration profile configuration is integrated into the measurement system, featuring a first calibration profile portion with multiple reference surface regions of known z heights, allowing for the determination and correction of sensor scale factor and tilt errors, thereby enhancing measurement accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chromatic point sensors are used for surface profile measurement, then measurement resolution is improved, but measurement accuracy deteriorates due to environmental instabilities and systematic misalignments
Solution Approach 1:
The patent applies preliminary action by incorporating a calibration profile with known reference surface regions into the measurement setup before actual measurements are taken. This calibration profile establishes reference z-height values and determines sensor scale factors and tilt parameters in advance, allowing the system to compensate for systematic misalignments and environmental instabilities during subsequent measurements, thereby maintaining both high resolution and accuracy
Solution Approach 2:
The calibration profile acts as an intermediary element between the sensor and the workpiece. It provides known reference surfaces that mediate the measurement process by enabling the determination of sensor scale factors and tilt parameters, which then serve as correction factors for all subsequent measurements, thus improving accuracy without compromising the high resolution capability of the chromatic point sensor
2Measurement precision
If reference objects are placed next to workpieces for calibration, then reference z height is established, but device complexity increases
Solution Approach 1:
The patent merges the calibration profile with the workpiece holder into a single integrated component. The calibration profile is directly formed on the workpiece holder, eliminating the need for separate reference objects placed next to the workpiece. This integration reduces device complexity by consolidating multiple elements into one while still providing the necessary reference surfaces for establishing z-height values and determining sensor parameters
3Measurement precision
If multiple calibration reference surfaces are included in scan path, then sensor scale factor and tilt errors are corrected, but measurement time increases
Solution Approach 1:
The calibration profile is designed to be measured continuously during the same scan pass used for measuring the workpiece. The sensor acquires data from both the calibration reference surfaces and the workpiece surface in a single continuous motion, eliminating the need for separate calibration and measurement passes. This maintains measurement precision through error correction while minimizing measurement time by ensuring continuous useful action throughout the scan
Data Source
AI summary
A combined workpiece holder and calibration profile configuration (CWHACPC) is provided for integration into a surface profile measurement system. The CWHACPC may comprise at least a first calibration profile portion and a workpiece holding portion that holds a workpiece in a stable position during measurement. The first calibration profile portion comprises a plurality of reference surface regions that have known reference surface z heights or z height differences relative to one another. The first calibration profile portion and the workpiece holding portion are configured to fit within a profile scan path range of the surface profile measurement system, such that the surface profile measurement system can acquire measured surface profile data for the first calibration profile portion and the workpiece during a single pass along the profile scan path. The acquired surface profile data for the reference surface regions may be used to indicate and/or correct certain errors.