Flexure Mounted Moving Mirror Reduces Vibration Noise
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Solution Overview
Problem
Conventional interferometers face challenges in accurately controlling the velocity and tilt of moving mirrors, leading to errors in spectral data due to vibration and noise from bearing imperfections, which cannot be completely corrected by existing laser-based servo control systems, especially for rapidly changing errors.
Innovation Solution
A hybrid moving mirror assembly incorporating a resiliently mounted reflector with a flexure bearing for short stroke movements and a long stroke linear bearing, coupled with a control system for precise velocity and tilt control, isolating vibrations and noise, and enabling faster response times for improved spectral data quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser-based velocity control servo is used to correct velocity errors, then slowly occurring velocity errors are corrected and largely eliminated, but rapidly changing velocity errors due to induced noise cannot be corrected completely
Solution Approach 1:
The flexure bearing pre-isolates the moving mirror from vibration and noise sources before they can affect the mirror position. This preliminary isolation reduces the magnitude of rapidly changing velocity errors, making them easier for the servo system to correct within its time delay constraints
Solution Approach 2:
The flexure bearing acts as an intermediary element between the moving mirror and the bearing support structure. It selectively transmits certain forces while isolating the mirror from high-frequency vibrations and noise, thereby improving velocity control accuracy without adding time delay to the servo system
2Measurement precision
If active control systems are used to control mirror tilt, then tilt errors are corrected, but the system complexity increases and adjustments are needed after shipping shocks
Solution Approach 1:
The flexure bearing provides passive, self-adjusting tilt control through its elastic deformation characteristics. As the moving mirror experiences forces or tilts, the flexure bearing naturally accommodates and corrects minor misalignments through its flexible structure, eliminating the need for complex active control systems and field adjustments
3Length of moving object
If conventional bearing systems are used for moving mirror support, then long stroke movements are enabled, but vibration and noise from bearing imperfections affect spectral data quality
Solution Approach 1:
The flexure bearing is introduced as an intermediary between the conventional bearing system and the moving mirror. It filters out high-frequency vibrations and noise from the bearing imperfections while allowing the mirror to execute its full stroke length, thereby enabling long stroke movements without transmitting harmful vibrations to the spectral data
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 hybrid configuration effectively corrects velocity and tilt errors, reduces noise and vibration, and enhances the stability of spectral data by allowing faster and more accurate control of the moving mirror, even with low-cost bearing systems, resulting in higher quality interferometer output.
Implementation Method 1
a resilient member coupled about a periphery of the reflector and coupled to a support structure, wherein the resilient member provides vibration isolation when flexed
Data Source
AI summary
A novel means of provided a hybrid flexure mounted moving mirror component in an interferometer is introduced herein. In particular, a linear bearing in combination with a novel flexure mounting having novel tilt and velocity control of the moving optical component is provided. Such an arrangement enables correction of the errors at the mirror itself while also solving the problem of isolating vibration and noise caused by the imperfections in the bearing surfaces used in many conventional interferometers. Using such a coupled flexure mounting of the present invention, in addition to the above benefits, also enhances velocity control because the resultant low mass of the moving mirror assembly enables the systems disclosed herein to respond faster than conventional mirror velocity controlled interferometer instruments and with a lower velocity error so as to provide a more stable and lower noise spectra from the analytical instrument.