Rotating Interferometer for Cylindrical Surface Measurement
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Solution Overview
Problem
Optical interferometric devices face challenges in efficiently measuring the three-dimensional shape of cylindrical surfaces due to the need for repeated scans and increased radial measurement ranges, which prolongs the measurement time.
Innovation Solution
An optical interferometric device with a rotation drive mechanism and a sensor using a two-dimensional array of photoreceptor elements, combined with a beam splitter and a tilt-adjustable reference mirror, allows for continuous measurement of cylindrical surfaces by rotating the interferometric optical system and acquiring two-dimensional distributions at varying rotation angles, enhancing sensitivity and reducing measurement time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image capture field of view is modified to cover the measurement target range on a cylindrical surface, then the measurement completeness is improved, but the measurement time increases
Solution Approach 1:
The patent transitions from scanning in the radial direction (one dimension) to rotating the optical system around the cylindrical surface (adding an angular dimension). This allows the sensor to capture multiple cross-sectional profiles simultaneously at different rotation angles, completing the measurement of the entire cylindrical surface without repeated radial scanning, thus reducing measurement time while maintaining completeness.
Solution Approach 2:
The patent implements continuous rotation of the interferometric optical system around the cylindrical object, enabling uninterrupted data acquisition. The sensor continuously captures interference patterns at varying rotation angles, eliminating the need for discrete scanning stops and adjustments, thereby reducing measurement time while maintaining measurement completeness.
2Measurement precision
If the radial measurement range is increased to cover the cylindrical surface, then the measurement coverage is improved, but the measurement complexity increases
Solution Approach 1:
Instead of increasing the radial measurement range (one dimension), the patent introduces rotation around the cylindrical surface (adding an angular dimension). This allows the same optical system to cover the entire cylindrical surface by capturing data at multiple rotation angles, reducing the required radial scan range and simplifying the measurement system while maintaining comprehensive coverage.
3Measurement precision
If repeated scans are performed to cover the measurement target range, then the measurement accuracy is improved, but the measurement time increases
Solution Approach 1:
The patent employs continuous rotation of the optical system to capture interference patterns at multiple rotation angles in a single continuous scan. This continuous acquisition method eliminates the need for repeated discrete scans, reducing measurement time while maintaining accuracy through comprehensive angular sampling of the cylindrical surface.
Solution Approach 2:
The patent adds the angular dimension by rotating the optical system around the cylindrical object, allowing simultaneous measurement of multiple cross-sectional profiles. This dimensional addition enables complete surface characterization in a single measurement cycle rather than requiring repeated radial scans, reducing time while preserving accuracy.
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 configuration enables rapid and accurate measurement of cylindrical surfaces by minimizing the need for radial displacement and allowing for efficient data acquisition across the surface, thereby shortening measurement time and improving sensitivity to surface unevenness.
Implementation Method 1
a beam splitter that splits incident light into reference light and measurement light, and that also outputs a composite wave that combines light that has traversed a reference light path and reflected light from the object
Implementation Method 2
a reference mirror that is provided on the reference light path and reflects the reference light. The reference mirror may be arranged so that it is tilted with respect to an optical axis of the reference light
Implementation Method 3
a sensor that acquires a two-dimensional distribution of the intensity of the composite wave using a plurality of photoreceptor elements arrayed two-dimensionally
Implementation Method 4
a rotation drive mechanism that is connected to the interferometric optical system and rotationally displaces the interferometric optical system centered about a rotation axis that coincides with a center axis of a cylindrical surface of the object
Data Source
AI summary
An interferometric optical device that measures the curved wall shape of a cylindrical object and includes: an interferometric optical system that emits measurement light at the curved wall of the object, collects the light reflected by the object, and creates a composite wave that combines the reflected light and a reference light; a rotation drive assembly that is connected to the interferometric optical system and rotationally displaces the interferometric optical system centered about a rotation axis that coincides with a center axis of the cylindrical shape of the object; a sensor that acquires a two-dimensional distribution of the intensity of the composite wave using a plurality of photoreceptor elements arrayed two-dimensionally; and a computation device that computes the internal wall shape of the object based on the plurality of two-dimensional distributions acquired in a state where a rotation angle for the rotation drive mechanism varies.