Security Window Conductive Glass Infrared Blocking
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Solution Overview
Problem
Current security windows fail to provide adequate infrared shielding while maintaining high visible light transmittance and clarity, and struggle with grounding for effective electromagnetic blocking across a wide frequency range.
Innovation Solution
The use of conductive glass substrates combined with layers of organic free radical compounds and multilayer interference stacks of metals or metal oxides, where the index of refraction is varied, to achieve both infrared reflectance and electromagnetic shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly electrically conductive filter layers with sheet resistance less than 4 ohms per square are used to achieve electromagnetic shielding, then electromagnetic radiation blocking is improved, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent divides the electromagnetic shielding function into separate layers: a first conductive layer (sheet resistance <4 ohms/sq) for electromagnetic radiation blocking, and a second conductive layer (sheet resistance <4 ohms/sq) for infrared radiation blocking. This segmentation allows each layer to be optimized for its specific function and simplifies the manufacturing process by enabling independent production and assembly of each layer.
Solution Approach 2:
The patent uses conductive glass substrates that simultaneously provide both electromagnetic radiation shielding and structural support. The conductive glass serves multiple functions: it acts as the substrate for the filter layers, provides electrical conductivity for grounding, and contributes to the overall mechanical strength of the window assembly.
2Reliability
If conductive glass substrates with low sheet resistance are used to achieve good electrical attenuation, then electromagnetic shielding is improved, but visible light transmittance decreases
Solution Approach 1:
The patent applies different optical and electrical properties to different parts of the window system. The conductive glass substrates have localized conductive properties in specific regions to achieve grounding and electrical attenuation, while maintaining high visible light transmittance in the overall window assembly. The filter layers are selectively positioned to block specific wavelength ranges while allowing visible light transmission.
3Ease of manufacture
If multiple layers with sheet resistance greater than 4 ohms per square are used, then manufacturing becomes easier, but infrared shielding effectiveness is reduced
Solution Approach 1:
The patent segments the infrared blocking function into a dedicated second conductive layer with sheet resistance less than 4 ohms/sq, separate from the electromagnetic radiation blocking function. This ensures that infrared shielding effectiveness is not compromised while still allowing the first layer to be manufactured with standard processes.
4Strength
If grounding of electromagnetic blocking layers is made difficult, then structural integrity is maintained, but electrical attenuation performance deteriorates
Solution Approach 1:
The conductive glass substrates serve dual purposes: they maintain structural integrity as the window substrate while simultaneously providing electrical pathways for grounding. The conductive glass can be connected to the building's grounding system through the window frame, achieving both structural and electrical functions without compromising either.
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 configuration effectively blocks radio frequency and infrared radiation while maintaining high visible light transmittance and clarity, and allows for easy grounding for enhanced electrical attenuation.
Implementation Method 1
conductive glass substrates... provide electromagnetic shielding... achieve good electrical attenuation over a wide range of frequencies
Implementation Method 2
conductive glass windows from Pilkington have been sold under the trade name of DATASTOP for shielding against electromagnetic radiation
Implementation Method 3
a layer of an organic free radical compound that is reflective at a range of wavelengths in the infrared
Implementation Method 4
block the transmission of radio frequency and infrared radiation... infrared transmission at wavelengths between 780 nm and 2500 nm of no more than 50%
Implementation Method 5
a multilayer interference stack of a metal/metal or a metal/metal oxide design where the index of refraction of alternating layers is varied to provide a desired infrared reflectance and blocking
Data Source
AI summary
A system of anti-surveillance security windows having one or more conductive glass substrates and one or more layers incorporating an organic radical cation compound, wherein the layers reflect in the infrared region, is demonstrated. Preferably, the organic radical cation compound is a salt of an aminium radical cation. The security windows may contain one or more layers of a multilayer interference stack of a metal/metal or metal/metal oxide design.