Vibration-Resistant Interferometric Scanning System
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Solution Overview
Problem
Conventional low-coherent interferometry struggles to accurately measure the surface profile of vibrating objects due to environmental disturbances, as it requires precise control over the distance between the interferometric objective and the measured object, which is challenging to maintain in the presence of vibrations.
Innovation Solution
A vibration-resistant interferometric scanning system and method that locks the brightness distribution of high-coherence interference patterns, allowing for specified shifting actions and compensation to maintain a fixed distance, effectively stabilizing the fringe distribution of low-coherence interference patterns, similar to those obtained for static objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional low-coherent interferometric scanning is used to measure surface profile, then measurement capability is provided, but measurement precision deteriorates under vibration conditions due to inability to maintain fixed distance between interferometric objective and measured object
Solution Approach 1:
The system uses a high-coherence interference pattern as a feedback signal to detect distance variations between the interferometric objective and the measured object. The brightness distribution of this pattern provides real-time information about distance changes, enabling the control unit to compensate for vibrations and maintain measurement precision despite unstable positioning.
2Stability of the object's composition
If anti-vibration devices are used to reduce vibration amplitude, then stability of the measured object is improved, but the object cannot be made completely static and device complexity increases
Solution Approach 1:
The high-coherence interference pattern serves as an intermediary that indirectly measures distance variations caused by vibrations. Instead of directly controlling vibrations through complex anti-vibration devices, the system uses the interference pattern as a mediator to detect and compensate for position changes, simplifying the overall system while maintaining measurement stability.
3Measurement precision
If low-coherent light is used to form interference pattern, then measurement of surface profile is enabled, but fringe distribution becomes non-uniform under vibration due to time-variant distance changes
Solution Approach 1:
The system performs preliminary action by using the high-coherence interference pattern to detect and compensate for distance variations before they affect the low-coherence interference pattern. The control unit uses brightness distribution information from the high-coherence pattern to pre-adjust for vibration-induced changes, ensuring uniform fringe distribution in the measurement pattern even under vibration conditions.
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 accurate surface profile measurement of vibrating objects by compensating for distance variations in real-time, ensuring clear and uniform interference patterns, thus overcoming the limitations of conventional low-coherent interferometry under vibration conditions.
Implementation Method 1
an interferometric objective, for receiving both the high-coherent light beam and the low-coherent light beam so as to respectively form a high-coherent interference pattern and a low-coherent interference pattern
Data Source
AI summary
A vibration-resistant interferometric scanning system and method are provided in the present invention. In the present invention, the brightness distribution in a high-coherence interference pattern is analyzed so as to perform a compensation action to lock the brightness distribution of a high-coherence interference pattern and consequently locking the fringe distribution of a low-coherence interference pattern or to perform a scanning operation composed of plural shifting actions with specified scanning distances in sequence and plural compensation actions to lock the fringe distribution in a low-coherence interference pattern corresponding to the surface profile of a measured object. Consequently, with the system and method of the present invention, the surface profile of a measured object disturbed by external or internal vibrations can be measured accurately and precisely.