Stress Manipulated Coating for Optical Substrate Figure Reshape
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Solution Overview
Problem
The next generation of X-ray missions requires a significant increase in effective area while maintaining low cost and mass, which is challenging due to the high cost and mass of current X-ray mirror assemblies, necessitating the development of thin and lightweight replicated optics with improved mirror quality.
Innovation Solution
A deposition system that forms a stress-distributed coating layer on the backside of optical substrates using a DC magnetron sputtering apparatus, adjusting bias voltage during deposition to correct surface figure errors and achieve the desired stress distribution, allowing for the reshaping of optical substrates to meet target surface profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional X-ray mirror assemblies are used to increase effective area, then the effective area increases, but the cost and mass increase significantly
Solution Approach 1:
The patent employs thin replicated optics with deposited coating layers instead of traditional thick mirror assemblies. The coating layer (50-500 nm thickness) is deposited on thin substrate shells, dramatically reducing mass while maintaining effective area. This approach enables lightweight optical elements that achieve the required 10 times area increase without proportional mass increase.
Solution Approach 2:
The patent uses replication techniques to create multiple identical optical elements from a single master mold. This copying approach enables mass production of thin optics with consistent figure quality, reducing both cost and mass compared to traditional individually fabricated mirrors while achieving larger effective areas.
2Weight of stationary object
If thin replicated optics are used to reduce mass, then mass decreases, but surface figure quality deteriorates
Solution Approach 1:
The patent controls surface figure quality by precisely controlling deposition parameters including bias voltage (-50 to -200 V), deposition rate (1-10 nm/min), and coating thickness (50-500 nm). These parameter changes enable the coating process to correct figure errors and achieve sub-arcsecond quality on thin replicated optics.
Solution Approach 2:
The patent replaces mechanical figure correction methods with a deposition-based stress control approach. By controlling intrinsic stress in the coating layer through bias voltage modulation during deposition, the system achieves figure correction without mechanical intervention, maintaining quality on thin lightweight structures.
3Ease of manufacture
If uniform coating deposition is used, then deposition process is simple, but surface figure errors cannot be corrected
Solution Approach 1:
The patent transforms the static uniform deposition process into a dynamic controlled deposition process. The bias voltage is modulated during deposition based on the local figure errors being corrected, allowing the coating stress to vary spatially and temporally. This dynamic control enables figure correction while maintaining process simplicity through automated feedback control.
Solution Approach 2:
The patent implements feedback control where surface figure measurements guide the deposition process. The measured figure errors determine the bias voltage profile during deposition, creating a closed-loop system that automatically corrects figure errors. This feedback mechanism maintains manufacturing simplicity by automating the correction process.
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 system effectively corrects surface figure errors by up to 10 arc-seconds, achieving stable and reproducible results without active control, suitable for applications in telescopes and synchrotron facilities, and demonstrates the potential for future X-ray observatories with improved resolution.
Implementation Method 1
a deposition system that forms a stress-distributed coating layer on the backside of optical substrates using a DC magnetron sputtering apparatus
Implementation Method 2
adjusting bias voltage during deposition to correct surface figure errors and achieve the desired stress distribution, allowing for the reshaping of optical substrates
Data Source
AI summary
A deposition system for forming a stress distributed coating layer is provided which comprises a deposition apparatus comprising a source from which a coating material emanates, the source configured to restrict a flux of the coating material towards a backside of an optical substrate; a holder configured to hold the optical substrate; a drive system configured to provide relative translation of the source and the optical substrate; and a bias voltage power supply operably coupled to the source and the optical substrate and configured to apply a bias voltage between the source and the backside of the optical substrate. A device is operably coupled to the deposition apparatus, the device comprising a processor; and a computer-readable medium operably coupled to the processor, the computer-readable medium having computer-readable instructions stored thereon that, when executed by the processor, cause the deposition apparatus to deposit the coating material onto the backside of the optical substrate and to adjust the bias voltage between the source and the backside of the optical substrate during the deposition of the coating material as a function of relative position of the source and the optical substrate to provide a stress distributed coating layer on the backside of the optical substrate.