Self-aligning spherical mirror assembly for FTIR interferometers
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Solution Overview
Problem
Existing mirror alignment systems in optical scientific instruments, such as FTIR interferometers, require high precision bearings and manual adjustments, which are time-consuming, costly, and prone to errors, especially due to temperature-induced tilt errors, leading to suboptimal instrument performance.
Innovation Solution
The implementation of a dynamic mirror alignment system using rotating mirrors with adjustable tilt control, allowing for automatic correction of mirror tilt errors through a control system, reducing the need for high precision bearings and enabling quick response to temperature-induced changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual alignment using differential screws is used, then mirror alignment precision can be achieved, but the procedure is time-consuming and requires significant skill
Solution Approach 1:
The system uses self-aligning spherical bearings that automatically position the mirror through gravity and geometry, eliminating the need for manual differential screw adjustments. The spherical interface allows the mirror assembly to self-center and self-align within the optical path, providing precise alignment without human intervention or specialized skills.
Solution Approach 2:
The patent replaces the complex mechanical differential screw adjustment system with a simpler spherical bearing support system. This substitution eliminates the need for threaded mechanisms and manual turning, using instead a geometrically-constrained spherical interface that provides alignment through pure mechanical support and gravity.
2Stability of the object's composition
If high precision bearings are used to support the mirror, then alignment stability is improved, but manufacturing cost and field service cost increase
Solution Approach 1:
The patent employs simple spherical bearings that can be manufactured at low cost using conventional machining. These bearings are designed to be replaceable and inexpensive, allowing easy field service replacement without requiring specialized components. The simplicity of the spherical geometry enables economical manufacturing while maintaining functional performance.
Solution Approach 2:
Instead of using complex precision bearings to achieve alignment, the patent inverts the approach by using simple spherical bearings with a precisely engineered spherical interface. The precision is achieved not in the bearing itself but in the mating spherical surfaces and their geometric relationship, allowing standard bearings to provide sufficient support.
3Speed
If piezoelectric positioners are used to dynamically adjust mirror tilt, then alignment correction speed is improved, but device size and cost increase significantly
Solution Approach 1:
The patent extracts the alignment correction function from complex piezoelectric positioners and implements it through the natural self-aligning behavior of the spherical bearing system. By removing the need for active correction mechanisms, the design achieves alignment stability through passive geometric constraints rather than active dynamic adjustment, eliminating large correction devices.
Solution Approach 2:
The patent uses optical feedback (laser alignment system) to detect mirror position and provides correction information to the control system, creating a closed-loop system that uses light-based measurement rather than mechanical sensing. This allows for precise alignment verification without requiring large mechanical correction devices.
4Ease of operation
If manual alignment procedures are used, then initial setup can be completed, but realignment during field service is required and time-consuming
Solution Approach 1:
The spherical bearing system provides automatic self-alignment during installation and operation, eliminating the need for manual realignment procedures during field service. The self-aligning geometry ensures that the mirror automatically returns to its correct position after any disturbance or temperature change, providing continuous alignment without intervention.
Solution Approach 2:
The patent incorporates an optical feedback system using a laser and position-sensitive detector that continuously monitors mirror alignment and provides real-time correction signals. This closed-loop feedback ensures automatic maintenance of alignment during operation and eliminates the need for periodic manual realignment during field service.
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
A mirror assembly has one or more axes of motion and includes a mirror that is movable and forms an acute angle with a plane orthogonal to its axis of motion. The mirror assembly may include a first reflective mirror surface in the incoming optical path that is movable and forms an acute angle with a plane orthogonal to its axis of motion, and a second reflective mirror surface in the outgoing optical path that is movable and forms an acute angle with a plane orthogonal to its axis of motion and is moveable in a linear translation to scan the mirror in the interferometer in a way to generate a normal interferogram.