Transparent Glass Heating Pattern Transfer Without Residual Film

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Solution Overview

Problem

Existing methods for forming heating elements on automotive glass suffer from issues such as high resistance at low voltages, visibility of metal lines, and distortions due to refractive index differences between films, which affect optical performance.

Innovation Solution

A method involving an adhesive film with controlled adhesive strength is used to form a conductive heating pattern, which can be transferred onto a transparent substrate without leaving a residual film, thereby improving optical properties and eliminating view distortions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a transparent conductive oxide film such as ITO is used to form a heating element, then optical transparency is improved, but heating value at low voltages deteriorates due to high resistance

Engineering Contradiction:
Improveoptical transparencyVSAvoidheating value at low voltages
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent uses a composite structure consisting of a transparent conductive oxide film (such as ITO) combined with a metal pattern (such as aluminum or silver). This composite approach allows the transparent conductive oxide to provide optical transparency while the metal pattern provides low resistance for effective heating at low voltages, thereby resolving the contradiction between transparency and heating performance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a thick tungsten wire is used for heating, then heating value at low voltages is improved, but optical transparency deteriorates due to visible metal lines

Engineering Contradiction:
Improveheating value at low voltagesVSAvoidoptical transparency
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by using a transparent conductive oxide film that is transparent in the visible spectrum to form the heating element pattern. This allows the heating function to be localized in specific areas while maintaining overall optical transparency, eliminating the visible metal lines problem associated with thick tungsten wires.

Inventive Principle:
Principle #3Local quality

3Reliability

If a PET film is inserted between two PVB films to form a heating element, then heating functionality is improved, but optical performance deteriorates due to view distortions from refractive index differences

Engineering Contradiction:
Improveheating functionalityVSAvoidoptical performance
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent extracts and removes the PET film from the structure by transferring the metal pattern onto a carrier film that is subsequently removed. This eliminates the source of refractive index differences and view distortions while preserving the heating functionality provided by the metal pattern on the carrier film.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If a metal pattern is formed on a PET film through printing or photolithography, then heating value at low voltages is improved, but manufacturing complexity increases due to additional processing steps

Engineering Contradiction:
Improveheating value at low voltagesVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-forming the metal pattern on a carrier film (such as a transparent conductive oxide-coated substrate) before transferring it to the final position. This preliminary formation of the pattern simplifies the overall manufacturing process by avoiding complex in-situ patterning steps and enabling easier integration into the glass assembly.

Inventive Principle:
Principle #10Preliminary action

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 method allows for the formation of a conductive heating pattern on transparent substrates without residual films, enhancing optical performance and reducing visibility of metal lines, while maintaining adequate heating value at low voltages.

Implementation Method 1

the adhesive film has an adhesive strength decrement of 30% or greater by an external stimulus based on adhesive strength before the external stimulus, wherein the external stimulus is one or more of heat, light irradiation, a pressure and a current

Methodology Applied
Scientific EffectAdhesive strength decrement by external stimulus:

Implementation Method 2

generating heat from the heating line by applying electricity to both terminals of the heating line, and increasing a temperature of the glass surface therefrom

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3451793B1Method for manufacturing heating element
Publication Date: 2025.08.27 LG CHEM LTD
  • EP3451793B1 patent drawingFigure 1
  • EP3451793B1 patent drawingFigure 2

AI summary

The present specification relates to a heating element and a method for manufacturing the same.