Radiofrequency-Transparent Heating Glazing With Segmented Lattice

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Solution Overview

Problem

Heated solar control glazing transparent to radio frequencies faces challenges in achieving sufficient heat for demisting and defrosting due to high surface electrical resistance, which requires additional metallic layers, compromising radio frequency transparency and increasing development and manufacturing costs.

Innovation Solution

Incorporating an electrically conductive mesh metal mesh with lower surface electrical resistivity over a stack of layers arranged in a periodic pattern, ensuring the mesh does not cover zones devoid of the stack, allowing for enhanced heat generation from low voltage supplies while maintaining radio frequency transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If metallic functional layers are added to increase electrical conductivity for heating, then heating efficiency is improved, but radio frequency transparency deteriorates

Engineering Contradiction:
Improveheating powerVSAvoidradio frequency attenuation
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The solution segments the electrical conduction function from the solar control function by introducing a separate meshed metal lattice layer that provides electrical conductivity for heating without requiring the solar control stack to be highly conductive. This allows the stack to maintain its radio frequency transparency properties while the lattice provides the necessary heating capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The meshed metal lattice acts as an intermediary element that mediates between the power supply and the glazing system. It provides the electrical conduction path needed for heating while being transparent to radio frequencies, thus resolving the conflict between heating efficiency and radio frequency transparency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If metallic layers are thickened to reduce surface resistivity, then heating efficiency is improved, but manufacturing cost increases

Engineering Contradiction:
Improveheating powerVSAvoidmanufacturing cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The solution divides the heating function from the solar control function, allowing the use of a simple, inexpensive meshed metal lattice for heating rather than requiring expensive, complex thick metallic layers integrated into the solar control stack. This segmentation reduces manufacturing complexity and cost.

Inventive Principle:
Principle #1Segmentation

3Power

If additional metallic layers are added to achieve sufficient heating, then heating efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveheating powerVSAvoidstack complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The solution segments the heating function into a separate meshed metal lattice layer, avoiding the need to modify the solar control stack structure. This keeps the stack design simple and allows independent optimization of both solar control and heating functions without increasing overall device complexity.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If the stack is designed for radio frequency transparency with periodic patterns, then radio frequency transparency is improved, but heating efficiency deteriorates due to high surface resistivity

Engineering Contradiction:
Improveradio frequency attenuationVSAvoidheating power
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The solution segments the radio frequency transparency function (handled by the periodic pattern in the solar control stack) from the heating function (handled by the meshed metal lattice). This allows each function to be optimized independently without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The meshed metal lattice provides universal electrical conduction capability that supports the heating function across the entire glazing surface, complementing the localized periodic pattern structure that provides radio frequency transparency. Together they create a multi-functional system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enables more efficient demisting and defrosting with reduced complexity and cost, offering greater freedom in choosing periodic patterns for radio frequency transparency and using more resistive solar control stacks, thus improving overall performance and reducing manufacturing costs.

Implementation Method 1

Thanks in particular to the metal layers it contains, the stack is an electrical conductor and, when supplied with electricity by the alternator and/or the vehicle battery, it can release heat by the Joule effect

Methodology Applied
Scientific EffectJoule effect: Joule Heating

Implementation Method 2

at least a portion of the stack, in particular the portion of the stack most exposed to telecommunication signals, is arranged in a periodic pattern so as to form a frequency-selective surface

Methodology Applied
Scientific EffectFrequency-selective filtering: Filter (electronic)

Data Source

PatentEP4222126B1Radiofrequency-transparent solar-control heating glazing
Publication Date: 2024.07.31 SAINT GOBAIN SEKURIT FRANCE
  • EP4222126B1 patent drawingFigure 1~2
  • EP4222126B1 patent drawingFigure 3~5
  • EP4222126B1 patent drawingFigure 6~7

AI summary

The invention relates to radiofrequency-transparent solar-control heating glazing. The subject matter of the invention is glazing (3000, 4000, 5000, 6000) comprising: - a sheet (3001) of transparent mineral glass comprising at least one main surface (3001a); - a stack (3002) of layers placed on said main surface (3001a) of said sheet (3001) of transparent mineral glass, said stack (3002) of layers comprising at least one metallic functional layer, and at least a portion (3004a) of said stack (3002) of layers being arranged in a periodic pattern so as to form a frequency-selective surface;- an electrically conducting meshed metallic lattice (3003) with a surface electrical resistivity lower than that of the stack (3002) of layers, - said lattice (3003) being superposed on said stack (3002) of layers so that, in the portion (3004a) of the stack that is arranged in the periodic pattern, the mesh of said lattice (3003) does not cover those zones (3005) of said periodic pattern that do not include the stack (3002) of layers.