Laser-Bonded Coated Substrates With Low-Absorption Interfaces

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for laser bonding of transparent substrates require coatings that absorb laser light, limiting design freedom and potentially damaging optical coatings due to the need for high absorption, which is not suitable for all applications.

Innovation Solution

A method where the coating on the substrates has minimal absorption (<10%) for the laser wavelength, allowing for reflective coatings and enabling hermetic bonding without the need for absorptive coatings, with localized laser treatment zones for bonding and selective heat treatment of coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If an absorptive coating is deposited at the interface between two glass sheets to enhance laser bond, then the laser irradiation is absorbed and power is accumulated to create a melting zone for bonding, but the coating must be absorbent for the laser wavelength, thus reducing design freedom for chemical composition and layer thickness

Engineering Contradiction:
Improvelaser bond strengthVSAvoiddesign freedom for coating
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent introduces a mediator substance (carbon-containing substance or organic compound) that facilitates laser energy absorption and conversion to heat without requiring the coating itself to be highly absorbent. This intermediary enables the bonding process while preserving design freedom for the coating's optical properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the mechanism from direct laser absorption by the coating to indirect heating through decomposition products. By changing the physical-chemical state and properties of the coating material during the process (decomposition at elevated temperatures), the system achieves bonding without requiring high initial absorption at the laser wavelength.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a reflective coating is applied to the substrate, then optical properties are improved and design freedom is increased, but the coating reduces laser energy absorption needed for bonding

Engineering Contradiction:
Improvecoating selection freedomVSAvoidlaser energy absorption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent uses an intermediary substance that bridges the gap between reflective coatings and laser bonding. The mediator (carbon-containing substance or organic compound) absorbs laser energy and converts it to heat through decomposition, allowing reflective coatings to be used without compromising bonding effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the direct optical absorption mechanism with a thermal decomposition mechanism. Instead of relying on the coating's optical absorption properties, the system uses thermal processes where the intermediary substance decomposes and generates heat, substituting optical interaction with thermal interaction.

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

3Strength

If high absorption coating is used to enhance laser bonding, then bonding strength is improved, but the coating may be damaged due to high laser energy concentration

Engineering Contradiction:
Improvebond strengthVSAvoidcoating damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a protective intermediary substance that absorbs and dissipates laser energy through controlled decomposition. This mediator protects the coating from direct high-energy laser exposure while still enabling sufficient heat generation for bonding, thus preventing coating damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful effect of high laser energy concentration into a beneficial process. The intermediary substance's decomposition absorbs the excess energy and transforms it into useful heat for bonding, while the decomposition products protect the coating from damage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

Enables hermetic bonding of substrates with increased design freedom, minimizing damage to coatings and allowing for complex structures and patterns, while maintaining the transparency and optical properties of the substrates.

Implementation Method 1

the coating, before laser treatment, has an absorption for light within the defined wavelength range of less than 10%

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a first laser treated zone comprising weld lines, wherein in the first laser treated zone material of the first substrate and the second substrate has been melted and mixed to bond the two substrates together

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

material of the first substrate and the second substrate has been melted and mixed

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4424651A1Bonded substrate arrangement and method for manufacturing of such an arrangement
Publication Date: 2024.09.04 SCHOTT AG
  • EP4424651A1 patent drawingFigure 1~2
  • EP4424651A1 patent drawingFigure 3~4
  • EP4424651A1 patent drawingFigure 5~6

AI summary

An arrangement (1) is provided comprising a first substrate (10), which is transparent in a defined wavelength range, and a second substrate (20) arranged next to the first substrate (10), wherein the first substrate (10) and/or the second substrate (20) have a coating (12, 22) formed on the side facing to-wards an interface between the first substrate (10) and the second substrate (20) and a first laser treated zone (50) comprising weld lines (100), wherein in the first laser treated zone (50) material of the first substrate (10) and second substrate (20) has been melted and mixed to bond the two substrates (10, 20) together. The coating (12, 22) of the first substrate (10) and/or second substrate (20) has, before laser treatment, an absorption for light within the defined wavelength range of less than 10%. Further aspects of the invention relate to a method for manufacturing such an arrangement and the use of such an arrangement.