Switchable Automotive Glazing With Capacitive Grounding Coatings

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Solution Overview

Problem

Existing automotive glazings with switchable films lack enhanced functionality and effective capacitive grounding, which affects their thermal and optical performance.

Innovation Solution

The integration of a switchable film with electrically conductive electrodes on polymer substrates within a picture-frame arrangement between interlayer materials and glass plies, along with infrared-reflective or low-emissivity coatings for capacitive grounding, provides additional functionality and improved thermal and optical modulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If switchable films are integrated into automotive glazings, then optical appearance modulation is achieved, but thermal durability is insufficient without additional functional layers

Engineering Contradiction:
Improveoptical appearance modulationVSAvoidthermal durability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent combines switchable film, infrared-reflective coating, and low-emissivity coating into a composite glazing structure. The infrared-reflective coating (21) is applied to the first glass ply (19) adjacent the picture-frame arrangement (15), while low-emissivity coatings (25, 26) are applied to glass plies (19, 20) to create a multi-functional composite that provides both optical modulation and thermal durability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The glazing structure integrates multiple functions into a single system: the switchable film (12) provides optical appearance modulation, the infrared-reflective coating (21) provides thermal reflection, and the low-emissivity coatings (25, 26) provide both thermal insulation and capacitive grounding. This multi-functional integration resolves the contradiction by achieving thermal durability without compromising optical modulation.

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

2Temperature

If infrared-reflective and low-emissivity coatings are added to glass plies, then thermal management is improved, but device complexity increases

Engineering Contradiction:
Improvethermal managementVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges capacitive grounding and thermal management functions into the existing glass plies and coatings. The infrared-reflective coating (21) and low-emissivity coatings (25, 26) serve dual purposes: thermal management and capacitive grounding, eliminating the need for separate grounding structures and reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The glass plies (19, 20) are designed to serve multiple functions: structural support, capacitive grounding through integrated coatings (21, 25, 26), and thermal management. This multi-functionality reduces device complexity by consolidating multiple functions into existing structural elements rather than adding separate components.

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

3Strength

If switchable film is laminated between interlayer materials and glass plies, then structural integrity is maintained, but capacitive grounding is ineffective without conductive coatings

Engineering Contradiction:
Improvestructural integrityVSAvoidcapacitive grounding
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces infrared-reflective coating (21) and low-emissivity coatings (25, 26) as intermediary conductive layers between the switchable film (12) and the external environment. These coatings serve as mediators that provide the necessary electrical pathways for capacitive grounding while maintaining the laminated structural integrity of the glazing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The glazing structure combines non-conductive interlayer materials (16, 17, 18) with conductive coatings (21, 25, 26) to create a composite structure that maintains structural integrity through the interlayers while enabling capacitive grounding through the conductive coatings on glass plies (19, 20).

Inventive Principle:
Principle #40Composite materials

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 enhances the thermal durability and optical appearance modulation of automotive glazings, offering superior performance compared to prior art by enabling effective capacitive grounding and improved thermal management.

Implementation Method 1

The first ply of glass (19) is provided with an infrared-reflective metallic film (21) on its lower surface

Methodology Applied
Scientific EffectInfrared reflection: Reflection

Implementation Method 2

A low-emissivity coating (25, 26) may be provided on each of the first and second plies of glass (19, 20)

Methodology Applied
Scientific EffectThermal radiation control: Thermal Radiation

Implementation Method 3

The switchable film 12 is laminated within the glazing as part of a picture-frame arrangement 15

Methodology Applied
Scientific EffectElectro-optic modulation: Electro-Optic Effects

Implementation Method 4

The coating (21, 22, 25, 26) used has a sheet resistance that is less than that of the material forming the electrodes (2, 3)

Methodology Applied
Scientific EffectCapacitive discharge: Capacitance

Data Source

PatentEP3366467B1Functional glazings
Publication Date: 2023.09.06 PILKINGTON GRP LTD
  • EP3366467B1 patent drawingFigure 1~2
  • EP3366467B1 patent drawingFigure 3~4

AI summary

An automotive vehicle having an aperture in the vehicle body in which a glazing, comprising a switchable film laminated between at least two plies of an interlayer material is fitted is disclosed. The plies of interlayer material are laminated between a first ply of glazing material, preferably glass, facing out of the vehicle and a second ply of glazing material, preferably glass, facing into the vehicle. The switchable film comprises first and second electrodes, both in electrical connection with a power supply. The first electrode is capacitively connected to electrical ground on the vehicle body.