Wired Glazing Busbar Adhesive Bonding Process

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Solution Overview

Problem

Existing glazing manufacturing processes for automotive windscreens with heating wires suffer from 'solder splash' and 'tin splash' faults due to the use of heated irons, leading to lower process yields and potential electrical connection issues.

Innovation Solution

The use of an adhesive layer to bond the first busbar to the interlayer material and an auxiliary adhesive layer to position the auxiliary busbar eliminates the need for heated iron steps, while coating all busbar surfaces with low melting point solder prevents 'tin splash' faults, ensuring stable electrical connections and positional control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a heated iron is used to embed the busbar in the interlayer material, then the busbar becomes securely fixed in position, but solder splash faults occur and electrical connection reliability deteriorates

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidpositioning precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

An adhesive layer is introduced as an intermediary substance between the busbar and the interlayer material. This adhesive layer enables secure bonding and positional control without requiring heated iron processing, thereby eliminating solder splash faults while maintaining reliable electrical connections between the heating wires and busbar assembly

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical/thermal embedding process using a heated iron is replaced with a chemical bonding process using an adhesive layer. This substitution eliminates the high-temperature processing step that causes solder splash, while still achieving secure fixation of the busbar in the interlayer material through adhesive bonding

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If low melting point solder is applied to the busbar surface, then electrical connection is improved, but tin splash faults occur during manufacturing

Engineering Contradiction:
Improveelectrical connection durabilityVSAvoidtin splash faults
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The busbar surfaces are pre-coated with low melting point solder before assembly. This preliminary action ensures that when the adhesive layer is applied and cured, the solder is already in position to provide durable electrical connections without requiring subsequent high-temperature soldering operations that would cause tin splash

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The melting point parameter of the solder is specifically selected to be low (lower than the autoclave temperature but sufficient to remain solid during assembly). This parameter change allows the solder to be applied in a controlled state and only melt during the autoclave process where it is contained, preventing tin splash faults while ensuring reliable electrical connections

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the manufacturing process is simplified to eliminate heated iron steps, then productivity is improved, but bonding reliability may deteriorate

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidbonding reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The adhesive layer serves as a mediator that enables reliable bonding without the need for heated iron processing. This allows the manufacturing process to be simplified and productivity improved, while the adhesive ensures bonding reliability is maintained or even enhanced through more consistent and controlled application

Inventive Principle:
Principle #24Intermediary (Mediator)

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 approach reduces 'solder splash' and 'tin splash' faults, improving process yield and maintaining durable electrical connections without detrimental effects on in-service performance, thereby enhancing the reliability of the glazing.

Implementation Method 1

an adhesive layer, bonding the first busbar to the ply of interlayer material

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

coating all busbar surfaces with low melting point solder prevents 'tin splash' faults, ensuring stable electrical connections

Methodology Applied
Scientific EffectLow melting point solder coating: Melting

Implementation Method 3

an auxiliary adhesive layer, arranged where an edge of the auxiliary busbar extends beyond an edge of the first busbar, bonding the auxiliary busbar to the ply of interlayer material

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3191303B1Wired glazing and a process for manufacturing thereof
Publication Date: 2021.03.17 PILKINGTON GRP LTD
  • EP3191303B1 patent drawingFigure 1~2
  • EP3191303B1 patent drawingFigure 3~4
  • EP3191303B1 patent drawingFigure 5~6

AI summary

A wired glazing is disclosed comprising a ply of interlayer material, having a first busbar and an auxiliary busbar and heating wires between them. An adhesive layer is arranged between the first busbar and the ply of interlayer material. An auxiliary adhesive layer is arranged where an edge of the auxiliary busbar extends beyond an edge of the first busbar. The auxiliary adhesive layer bonds the auxiliary busbar to the ply of interlayer material. A corresponding process for manufacturing a wired glazing is disclosed.