Randomized Circular Grid Sensor Window Shielding
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Solution Overview
Problem
Conventional metallized coatings for optical and infrared sensor windows provide inadequate broadband optical/infrared transmission while meeting electromagnetic interference (EMI/EMP) shielding requirements, due to significant scattering and diffraction effects, especially at off-normal incidence angles.
Innovation Solution
A Randomized Circular Grid (RCG) pattern is introduced, where overlapping ellipses or circles replace the traditional hub-spoke design, eliminating straight edges and ensuring electrical continuity, thereby reducing diffraction scattering and improving infrared transmission across all incidence angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If continuous metal films are applied to sensor windows for EMI/EMP shielding, then electromagnetic shielding performance is improved, but infrared transmission capability deteriorates to poor or zero levels
Solution Approach 1:
The continuous metal film is segmented into discrete conductive elements (circles, squares, triangles, or irregular shapes) arranged in a grid pattern. This segmentation allows the coating to block EMI/EMP energy through the conductive elements while maintaining open spaces between them that permit infrared and visible light transmission, thereby resolving the contradiction between shielding effectiveness and optical transmission.
2Object-affected harmful factors
If straight-line wire meshes or photolithographic grids are applied to sensor windows, then EMI/EMP shielding is achieved, but optical scattering and diffraction increase significantly
Solution Approach 1:
The patent replaces straight-line wire meshes and photolithographic grids with conductive elements having curved or non-linear boundaries (circles, squares, triangles, or irregular shapes). This geometric change eliminates the straight edges that cause significant diffraction and scattering of optical energy, while the conductive elements maintain their ability to shield against EMI/EMP. The curved boundaries reduce diffraction effects because they do not create the sharp discontinuities in the electromagnetic field that straight lines produce.
3Object-affected harmful factors
If hub-spoke patterns with straight-line interconnectors are used, then EMI/EMP shielding is maintained, but optical scattering is reduced only partially
Solution Approach 1:
The patent extracts and removes the straight-line interconnectors (spokes) from the hub-spoke pattern, retaining only the conductive elements (circles, squares, triangles, or irregular shapes) arranged in a grid. By eliminating the straight-line connections between elements, the design removes the primary source of diffraction and scattering while maintaining EMI/EMP shielding through the distributed conductive elements themselves, which remain electrically connected through alternative pathways or direct contact points.
4Object-affected harmful factors
If conventional metallized coatings are applied, then EMI/EMP shielding requirements are met, but broadband optical/infrared transmission requirements cannot be met
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of conductive elements with varying sizes, shapes, and spacing across the window surface. Different regions have different densities and configurations of conductive elements, allowing optimization of both EMI/EMP shielding and optical transmission in different areas. This localized variation enables the coating to meet broadband transmission requirements while maintaining adequate shielding performance across the entire window.
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 RCG pattern significantly reduces optical and infrared diffraction, achieving improved broadband transmission and scattering reduction by eliminating the sources of side lobe scattering characteristic of straight-line diffraction, resulting in enhanced image quality and EMI/EMP shielding.
Implementation Method 1
A conductive surface coating applied to a sensor window may be used to pass optical energy while blocking EMI/EMP energy, by conducting it directly to the surrounding window frame
Implementation Method 2
A conductive surface coating applied to a sensor window may be used to pass optical energy while blocking EMI/EMP energy
Implementation Method 3
These straight-line meshes and grids provide adequate EMI/EMP shielding, but the grid and wire patterns they employ generate significant scattering and diffraction of transmitted optical and IR energy
Data Source
AI summary
A method of electromagnetically shielding a sensor window with a metallization coating including providing a randomized elliptical grid pattern having a plurality of randomly distributed elliptical shapes, where providing includes arranging the elliptical shapes on the sensor window such that the elliptical shapes are physically connected to each-other as a result of direct shape-to-shape contact or overlap, where arranging includes increasing a pattern density, which is a ratio of elliptical shapes per unit of sensor window area, towards an edge of the sensor window; and where the elliptical shapes are hollow to allow for transmission of electro-optical radiation through the sensor window.