White Light Interference Shape Measurement Without Z-Scanning
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Solution Overview
Problem
Conventional fine shape measurement using white light interferometers requires precise scanning in the Z-axis direction and cannot completely eliminate the effects of vibration, necessitating consideration of position shifts between images.
Innovation Solution
A system that measures the light path difference from a single image of interference fringes using a storage section and calculation section, allowing for the measurement of light path differences between pixels and eliminating the need to consider shifts in the XY-axis directions due to vibration, enabling shape measurement without Z-axis scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precise scanning in Z-axis direction is performed to achieve accurate shape measurement, then measurement precision is improved, but measurement time increases and vibration effects cannot be completely eliminated
Solution Approach 1:
The patent replaces the mechanical scanning system with an optical field-based measurement approach. By utilizing the interference field distribution in the XY plane and mathematical reconstruction algorithms, the system achieves Z-axis shape information without physical Z-axis scanning motion, thereby eliminating vibration effects and reducing measurement time while maintaining precision
Solution Approach 2:
The patent transforms the measurement approach by capturing interference patterns in the XY plane (two dimensions) and using computational methods to reconstruct Z-axis height information (third dimension). This dimensional transformation allows obtaining 3D shape data from 2D interference fringe patterns without requiring physical scanning in the Z direction
2Reliability
If precise scanning is performed to eliminate position shifts between images, then measurement reliability is improved, but productivity decreases
Solution Approach 1:
The patent replaces mechanical scanning with optical field analysis. By capturing a single interference pattern and using computational algorithms to extract height information, the system eliminates the need for repeated scanning and image alignment, thereby improving both reliability (by eliminating vibration-induced position shifts) and productivity (by reducing measurement time)
3Measurement precision
If multiple images are captured during scanning to achieve accurate Z-axis positioning, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical scanning systems with a simplified optical capture system. By using a single camera to capture interference patterns and applying mathematical reconstruction algorithms, the system achieves accurate Z-axis height measurement without requiring complex scanning mechanisms, thereby reducing device complexity while maintaining precision
Solution Approach 2:
The patent creates a computational model (digital copy) of the physical object's surface by reconstructing height information from interference fringe patterns. This digital reconstruction allows accurate representation of the object's shape without requiring physical contact or complex scanning mechanisms
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
Enables high-speed shape measurement of objects by generating a single image, reducing the impact of vibrations and eliminating the need for multiple scans, thereby improving measurement efficiency.
Implementation Method 1
Measurement device employing color appearing due to interference of white light
Data Source
AI summary
A device including: a storage section that stores information for measuring a light path difference of two light paths relating to interference of a white light, from a color appearing due to the interference; and a calculation section that measures, from an image configured by a plurality of pixels each including information representing a color, the light path difference relating to each of the pixels, based on at least the information stored in the storage section.