Interferometric Machining Device for Precise Groove Shape Measurement
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Solution Overview
Problem
Existing machining devices using optical interferometry face challenges in accurately measuring grooves due to faint reflected light and pseudo interference fringes, leading to low signal-to-noise ratios and misrecognition of noise, which destabilizes the extraction of intrinsic shapes.
Innovation Solution
A machining device equipped with an imaging unit that uses optical interferometry, including a drive unit for Z-axis scanning, controlled illumination light intensity, gain adjustment, exposure time, and gradation correction, and image processing to enhance image quality and precision in measuring machined workpieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical interferometry is used to measure groove shape, then measurement capability is provided, but reflected light from inside the groove is faint causing low S/N ratio and misrecognition of noise
Solution Approach 1:
The patent applies local quality by making different parts of the imaging system have different functions: the illumination unit provides enhanced illumination specifically for groove areas, the imaging unit captures interference patterns from different depths, and the image processing unit applies specific algorithms to different regions. This localized optimization improves the S/N ratio for groove measurements without compromising overall system performance.
Solution Approach 2:
The patent performs preliminary action by conducting Z-axis scanning to capture interference images at multiple depth positions before final shape extraction. The image processing unit first identifies groove regions, then applies appropriate processing parameters to those specific areas. This preliminary identification and multi-depth imaging prepares the data in advance, enabling more reliable shape extraction despite faint reflected light.
2Measurement precision
If optical interferometry is used to measure groove shape, then measurement capability is provided, but pseudo interference fringes are generated causing misdetection and destabilizing shape extraction
Solution Approach 1:
The patent applies the taking out principle by extracting only the useful interference information from the captured images while removing pseudo interference fringes through image processing. The image processing unit selectively extracts shape information from valid interference patterns and eliminates artifacts, separating the desired measurement data from harmful pseudo fringes that would otherwise destabilize shape extraction.
Solution Approach 2:
The patent implements feedback by using the image processing unit to analyze captured interference images, identify the presence of pseudo interference fringes, and adjust processing parameters accordingly. The system continuously monitors image quality and refines the shape extraction process based on feedback from image analysis, thereby compensating for and eliminating the effects of pseudo interference fringes.
3Measurement precision
If imaging conditions are optimized for each site, then measurement accuracy is improved, but device complexity increases due to multiple control parameters
Solution Approach 1:
The patent applies merging by combining multiple imaging control functions (illumination control, exposure time control, gain adjustment, and image processing) into an integrated imaging control unit. This unified controller manages all imaging parameters and coordinates the illumination unit, imaging unit, and image processing unit, reducing operational complexity while maintaining optimized imaging conditions for different sites such as groove areas and flat surfaces.
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 device achieves precise measurement of machined workpiece shapes by optimizing imaging conditions and processing techniques, reducing noise interference and improving the signal-to-noise ratio, thereby enhancing measurement accuracy.
Implementation Method 1
an imaging unit (60) which images a surface of the workpiece using an optical interferometry
Implementation Method 2
a drive unit (30ZB) which moves the imaging unit (60) relative to the table (10), along a direction of the Z-axis
Data Source
AI summary
Provided is a machining device capable of precisely measuring a shape of a machined workpiece. The machining device includes: a table configured to hold a workpiece on a holding surface perpendicular to a Z-axis; a machining unit configured to machine the workpiece on the table; an imaging unit configured to image a surface of the workpiece using an optical interferometry; a drive unit configured to move the imaging unit along a direction of the Z-axis relative to the table; and an imaging control unit configured to control the drive unit and the imaging unit to image the surface of the workpiece on the table through scanning in the direction of the Z-axis. The imaging control unit picks up an image of the surface of the workpiece through scanning in the direction of the Z-axis, in accordance with an imaging condition determined for each site to be imaged.