Optical Window Temperature Sensing for Local Thermal Aberration Control
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Solution Overview
Problem
Current optical windows in airborne imaging systems suffer from aerodynamic heating, leading to thermally-induced wavefront errors and optical distortions, for which there are no direct methods to measure and correct the temperature distribution across the aperture.
Innovation Solution
Integration of a thermally sensitive material between electromagnetic interference shielding layers in the optical window, allowing for direct and local measurements of window temperature and dynamic temperature control through a two-dimensional array of electrically conductive wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermal camera is placed behind the aperture to measure thermal gradients, then temperature distribution can be recorded, but system size, weight, power, and cost increase
Solution Approach 1:
The patent combines the temperature measurement function with the existing optical window structure by integrating a thermally sensitive material and EMI shield into the window itself. This merging eliminates the need for a separate thermal camera system, thereby reducing system size, weight, power, and cost while maintaining temperature distribution measurement capability.
Solution Approach 2:
The optical window is designed to serve multiple functions: it provides electromagnetic interference shielding, enables temperature measurement through the thermally sensitive material, and maintains optical transparency. This multi-functionality eliminates the need for additional dedicated temperature measurement equipment.
2Reliability
If uniform heating is applied to correct thermal gradients, then wavefront errors are reduced, but emissions and noise increase
Solution Approach 1:
The patent implements local quality by enabling spatially selective heating through the EMI shield, which can be independently controlled in different regions. This allows temperature correction to be applied only where needed rather than uniformly across the entire aperture, reducing unnecessary thermal emissions and associated noise while maintaining optical performance.
3Temperature
If resistive heating wires are embedded to heat the aperture, then thermal gradients are corrected, but system complexity and power consumption increase
Solution Approach 1:
The patent implements dynamic temperature control by allowing independent adjustment of heating in different spatial regions of the EMI shield. This dynamic capability enables the system to apply heating only where and when needed to correct thermal gradients, optimizing power consumption rather than continuously heating the entire aperture.
4Reliability
If no temperature measurement method is used, then system complexity is reduced, but thermally-induced wavefront errors cannot be corrected
Solution Approach 1:
The temperature measurement and control functions are merged into the optical window structure itself through the integration of thermally sensitive material and EMI shield with independent voltage control. This eliminates the need for separate external measurement and control systems, reducing overall device complexity while enabling optical performance correction.
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 real-time, high-spatial resolution temperature measurements and active correction of thermally-driven aberrations, improving optical performance with minimal impact on system size, weight, power, and cost (SWaP-C).
Implementation Method 1
measuring a temperature-dependent electrical property of a thermally sensitive material included in the optical window
Implementation Method 2
selectively biasing at least one wire of the two-dimensional array of electrically conductive wires to locally alter the temperature-dependent electrical property
Data Source
AI summary
A method of controlling a temperature profile of an optical window comprising: measuring a temperature-dependent electrical property of a thermally sensitive material included in the optical window using an embedded electromagnetic interference shield in the optical window to determine the temperature profile of the optical window, the embedded electromagnetic interference shield including a two-dimensional array of electrically conductive wires; and based on the measurements, selectively biasing at least one wire of the two-dimensional array of electrically conductive wires to locally alter the temperature-dependent electrical property of the thermally sensitive material in at least one selected spatial region of the optical window to control the temperature profile of the optical window.