Surface Shape Measurement Error Compensation Feedback
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Solution Overview
Problem
Existing surface shape measurement technologies face challenges in achieving precise measurements due to placement errors of the measurement object relative to the stage, leading to inaccuracies in surface shape data.
Innovation Solution
A surface shape measurement apparatus and method that updates the target placement position using placement error calculations, recalculates the placement error between the actual and target positions, and reupdates surface shape data using angle and distance measurement devices to ensure accurate positioning and measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface shape measurement is performed using known measurement technologies, then measurement can be completed, but placement errors of the measurement object relative to the stage cause measurement precision to deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where the measurement result is used to calculate placement error, which then corrects the target placement position for subsequent measurements. The computation part calculates placement error based on the difference between actual and target positions, updates the target placement position using this error, and recalculates surface shape data. This closed-loop feedback system continuously improves measurement accuracy by compensating for placement errors without requiring manual intervention or remeasurement.
Solution Approach 2:
The patent changes the parameter of target placement position dynamically based on calculated placement errors. Instead of using a fixed target position, the system updates the target placement position by adding the calculated placement error to it. This parameter change allows the measurement system to adapt to actual placement variations and maintain high measurement precision despite initial positioning inaccuracies.
2Measurement precision
If placement error correction is implemented through iterative recalculation, then measurement precision is improved, but calculation complexity and processing time increase
Solution Approach 1:
The system performs self-correction by automatically calculating placement errors from measurement data and using these errors to update target positions and recalculate surface shape data. The computation part autonomously processes the correction without external intervention, making the system self-sufficient in maintaining measurement accuracy. This self-service approach reduces the need for complex external correction mechanisms while improving precision.
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 precise surface shape measurement by compensating for placement errors, improving the accuracy of surface shape data and reducing measurement inaccuracies, thereby enhancing the overall measurement precision.
Implementation Method 1
an angle measurement device which measures inclination of a surface of the measurement object at a measurement point using first probe light
Implementation Method 2
a distance measurement device which measures a distance to the measurement point using second probe light
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
A surface shape measurement apparatus includes: a stage which supports a measurement object; a measurement device which measures a surface shape of the measurement object in a contactless manner; an computation part which computes surface shape data of the measurement object based on an output value of the measurement device and predetermined reference shape data of the measurement object; and a calculation part which calculates, based on information of a target placement position of the measurement object on the stage, the surface shape data and the reference shape data, a placement error between an actual placement position of the measurement object on the stage and the target placement position, wherein the computation part updates surface shape data of the measurement object using the placement error.