Heatable Glazing Continuous Solder Layer

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Solution Overview

Problem

The existing process for manufacturing heatable glazings, such as automotive windscreens, is slow, expensive, and generates tin residues due to punctual soldering of heating wires to busbars, leading to low adhesion and production yield reduction.

Innovation Solution

A laminated glazing assembly with a thermoplastic interlayer, busbars, and heating wires, where a low-melting point solder layer and an adhesive layer between the busbars facilitate a fast and durable electrical connection, allowing for pre-binding during the lamination process without the need for extensive manual soldering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If punctual soldering is used to bind heating wires and busbars, then electrical connection is achieved, but the process is slow, expensive, and generates tin residues

Engineering Contradiction:

Improveelectrical connection qualityVSAvoidmanufacturing speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The invention changes the soldering approach from punctual (localized) soldering to a continuous solder layer applied on the busbar surface. This parameter change in the soldering method enables faster manufacturing while maintaining reliable electrical connection, as the continuous solder layer is applied in one step during lamination rather than requiring multiple punctual soldering operations.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The solder layer is pre-applied to the busbar surface before the lamination process. This preliminary action ensures that when the heating wires and busbars are assembled, the solder is already in position to create electrical connections, eliminating the need for post-assembly soldering operations and significantly speeding up the manufacturing process.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If punctual soldering is used to bind heating wires and busbars, then electrical connection is achieved, but adhesion is low and production yield is reduced

Engineering Contradiction:

Improveelectrical connection qualityVSAvoidadhesion quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention changes from punctual soldering to a continuous solder layer configuration. This parameter change ensures that the entire contact surface between the heating wire and busbar is covered with solder, not just discrete points, thereby significantly improving adhesion quality and reducing production yield loss due to poor bonding.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The solder layer acts as an intermediary material between the heating wire and the busbar. This intermediary substance provides a reliable bonding interface that ensures both electrical connection and mechanical adhesion, preventing the heating wires from detaching during storage and positioning before lamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If low melting point solder is used, then electrical connection is improved, but the process requires autoclave heating

Engineering Contradiction:

Improveelectrical connection qualityVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the soldering process with the lamination autoclave heating step. By using low melting point solder that melts at temperatures already required for lamination, the patent combines two separate processes (soldering and lamination) into one, eliminating the need for a separate soldering step and reducing overall process complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The low melting point solder material self-activates during the lamination autoclave heating process. The heat required for lamination automatically triggers the melting and bonding of the solder, eliminating the need for additional heating equipment or separate soldering operations. The system uses its own lamination heat to perform the soldering function.

Inventive Principle:

Principle #25Self-service

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 reduces in-service failure rates and simplifies the manufacturing process by ensuring a strong, reliable electrical connection and improved adhesion between busbars and heating wires, while eliminating tin residues and enhancing production efficiency.

Implementation Method 1

a low melting point solder layer which melts in a lamination autoclave

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

an adhesive layer is arranged between the first busbar and the second busbar

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 3

an array of heating wires extends between, and is in electrical contact with first and second busbars for supplying electrical power to the array of heating wires

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11440294B2Heatable glazing

Publication Date: 2022.09.13 AGC GLASS EUROPE SA

AI summary

A laminated glazing comprising an assembly including (i) at least a thermoplastic interlayer, (ii) a first busbar laid over the thermoplastic interlayer, (iii) at least one heating wire laid over the first busbar, (iv) a second busbar at least partly laid over the heating wire and at least partly laid over the first busbar, (v) where a solder layer suitable for melting in an autoclave covers at least part of a surface of the first busbar or the second busbar and is arranged to contact the heating wire, and (vi) where the assembly is laminated with at least a glass sheet.