Rear-Assembled Segmented Optical Mirror for Thermal Stability
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Solution Overview
Problem
Current methods for producing large mirrors are either costly or impractical due to the need for active alignment systems or large production equipment, and existing solutions for assembling small optical surfaces result in unstable assembly areas that affect the mirror's stability and thermal expansion.
Innovation Solution
A method involving the assembly and fixation of optical surfaces from the rear onto a supporting structure with thermoelastic stability, using materials like Zerodur or Si3N4, ensuring minimal thermal expansion mismatch, and polishing after assembly to create ultra-stable mirrors without active repositioning systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mirrors are produced by assembling a plurality of optical surfaces having small dimensions, then the production cost and complexity are reduced, but the assembly stability and thermal expansion consistency deteriorate
Solution Approach 1:
The patent inverts the conventional assembly approach by assembling optical surfaces from the rear side rather than from the front. The supporting structure is first formed with a rear opening, then optical surfaces are inserted and fixed from the rear. This inversion allows the assembly areas to be located on the rear side which does not form part of the polished optical surface, thereby maintaining assembly stability without affecting optical performance.
Solution Approach 2:
The patent applies local quality by differentiating the functional requirements of different regions: the rear assembly areas use materials and structures optimized for mechanical stability and thermal compatibility, while the front optical surfaces are optimized for optical performance. The supporting structure and fixing means are specifically designed with thermoelastic properties matched to the optical surfaces, while the polished surfaces are designed for optimal optical characteristics.
2Manufacturing precision
If mirrors are produced by assembling optical surfaces from the front, then the alignment precision can be optimized, but the thermal expansion mismatch and assembly stability deteriorate
Solution Approach 1:
By inverting the assembly direction to from-the-rear, the patent positions the assembly and fixing operations away from the polished optical surface. This ensures that the thermal expansion characteristics of the assembly areas do not affect the optical surface, as the fixing means and supporting structure are located on the rear side where they cannot introduce thermal mismatch into the optical path.
3Stability of the object's composition
If monolithic mirrors are produced, then the structural stability is improved, but the production cost and equipment requirements deteriorate
Solution Approach 1:
The patent segments the mirror into multiple optical surfaces that can be manufactured separately and then assembled from the rear. This segmentation allows for more flexible manufacturing - each optical surface can be produced using standard equipment, and the modular assembly from the rear provides structural stability comparable to monolithic mirrors without requiring expensive large-scale production facilities.
4Ease of manufacture
If assembly areas are included in the polished surface, then the manufacturing process is simplified, but the optical quality and thermal stability deteriorate
Solution Approach 1:
The patent inverts the conventional approach by making the assembly areas located on the rear side of the mirror, separate from the polished optical surface. This ensures that the fixing means and supporting structure do not interfere with the optical quality of the polished surface, while still providing necessary structural support and stability.
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 approach enables the production of ultra-stable, thermally compatible optical mirrors with low thermal expansion, suitable for space observation, without the need for active alignment and compatible with mirrors of any dimension, ensuring a smooth reflecting surface.
Implementation Method 1
the difference in coefficient of thermal expansion between the elements and the supporting structure being less than a threshold value, the threshold value is 5 μm/m/K
Implementation Method 2
a supporting structure made from a material having thermoelastic stability equivalent to that of the optical surfaces of the mirror
Data Source
AI summary
A method for producing a mirror comprising a plurality of optical surfaces, the method comprises: a step of producing elements, step of assembling the elements with each other from the rear, a step of fixing the elements from the rear onto a supporting structure of the mirror, and a step of polishing subsequent to the step of fixing the elements in order to obtain the optical surfaces of the mirror and correct the residual positioning defects of the optical surfaces and polish them.