Defect-Free Thin Glass Bonding via Electrostatic Pressure

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Solution Overview

Problem

The handling and processing of thin glass substrates are challenging due to their thin nature, which can lead to warping, breakage, and defects such as bubbles and inclusions during bonding with support substrates, especially under high temperatures, limiting their application in technologies like OLED displays and thin film batteries.

Innovation Solution

A method combining electrostatic adhesion and external pressure to bond thin glass substrates with support substrates without an interlayer, using a roller to apply mechanical pressure and electrostatic charging to ensure defect-free bonding, allowing for high-temperature processing and easy de-bonding without residue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thin glass substrate is bonded to support substrate by adhesive interlayer, then adhesion is achieved, but high temperature stability is lost and residues remain after de-bonding

Engineering Contradiction:

Improveadhesion strengthVSAvoidhigh temperature stability

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The patent removes the adhesive interlayer from the bonding system, achieving direct bonding between thin glass substrate and support substrate. This extraction eliminates the temperature limitations and residue problems inherent in polymer adhesives, allowing the glass-glass interface to withstand high temperatures without degradation or residue formation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the chemical bonding mechanism of adhesives with a physical bonding mechanism based on surface energy and van der Waals forces. This substitution enables thermal stability comparable to the glass substrates themselves, as the bonding interface no longer relies on temperature-sensitive polymer chemistry.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If thin glass substrate is handled without support, then processing flexibility is maintained, but warping and breakage occur

Engineering Contradiction:

Improveprocessing flexibilityVSAvoidstructural stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent segments the handling system into two functional parts: the thin glass substrate providing flexibility and surface quality, and the support substrate providing structural stability. This segmentation allows each component to fulfill its optimal function while bonded together.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a composite structure combining thin glass substrate with support substrate, where the composite provides both the flexibility needed for processing and the structural stability required to prevent warping and breakage during handling and high-temperature treatment.

Inventive Principle:

Principle #40Composite materials

3Strength

If adhesive bonding is used, then bonding strength is achieved, but de-bonding becomes difficult and costly

Engineering Contradiction:

Improvebonding strengthVSAvoidde-bonding ease

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent employs a temporary support substrate that is designed to be easily removed after serving its protective function. The direct glass-glass bonding interface allows for clean separation without the need for chemical solvents or complex de-bonding processes required by adhesive systems.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 method produces defect-free bonded articles that can withstand high temperatures and maintain surface quality, enabling precise processing and reducing breakage risks, thus enhancing the usability of thin glass substrates in various applications.

Implementation Method 1

bonding one of the first and second surfaces of the support member to one of the first and second surfaces of the substrate member gradually under rotation and movement of the roller by means of electrostatic force and mechanical pressure exerted by the roller

Methodology Applied

Scientific EffectMechanical pressure: Compression

Implementation Method 2

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS11225057B2Bonded article of thin glass on support substrate, preparation method and use thereof

Publication Date: 2022.01.18 SCHOTT GLASS TECH (SUZHOU) CO LTD

AI summary

A method for making a bonded article, wherein a thin glass substrate is bonded on a support substrate in the absence of any interlayer by an electrostatic adhesion process with the assistance of external pressure, the pressure is applied constantly or stepwise during the adhesion process by use of a tool such as a roll or a wheel or other movable device with curved surface. The bonded article has no defects, e.g. bubbles or inclusions, in the bonded interface, which benefits transportation of the thin glass substrate and its post-processing as well. Such defect-free bonded article is also disclosed. Pressure supported electrostatic adhesion, initiated by electrostatic charges adhesion of a two members, e.g. a substrate member and a support member, is enabled to minimize, prevent and exclude defects, distortion between the adhered surfaces.