Flexible Glass Cover Window with Variable Thickness and Depth of Layer

Solution Overview

Problem

Conventional glass-based flexible cover windows face challenges in simultaneously achieving sufficient strength and folding properties due to imbalanced central tension values between the plane and folding parts, leading to issues like natural explosion, breakage, and waviness, especially when subjected to repeated folding and external impacts.

Innovation Solution

A glass-based flexible cover window with a folding part that is slimmed to be thinner than the plane part, featuring a depth of layer adjustment to ensure the central tension of the plane part is greater than the folding part, with chemical tempering treatment and possible additional processes like etching or reverse ion exchange to balance central tension values, and a thickness range of 50 to 300 μm for the cover window and 20 to 100 μm for the folding part.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the glass thickness is increased to satisfy strength requirements, then the strength property is improved, but the folding property deteriorates due to excessive thickness

Engineering Contradiction:

Improvestrength propertyVSAvoidfolding property

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The cover window is divided into two distinct regions: a first region (folding area) with first thickness and a second region (non-folding area) with second thickness. This segmentation allows each region to have optimized thickness for its specific function - the folding area is thinner for flexibility while the non-folding area is thicker for strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different thickness values are applied to different locations of the cover window. The folding area has a first thickness optimized for bending, while the non-folding area has a second thickness optimized for strength and impact resistance. This local differentiation resolves the contradiction between overall strength and localized folding capability.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the glass thickness is decreased to satisfy folding requirements, then the folding property is improved, but the strength property deteriorates

Engineering Contradiction:

Improvefolding propertyVSAvoidstrength property

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The cover window is divided into two distinct regions: a first region (folding area) with first thickness and a second region (non-folding area) with second thickness. This segmentation allows each region to have optimized thickness for its specific function - the folding area is thinner for flexibility while the non-folding area is thicker for strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different thickness values are applied to different locations of the cover window. The folding area has a first thickness optimized for bending, while the non-folding area has a second thickness optimized for strength and impact resistance. This local differentiation resolves the contradiction between overall strength and localized folding capability.

Inventive Principle:

Principle #3Local quality

3Strength

If the central tension value is increased to improve strength, then the strength property is improved, but natural explosion may occur due to excessive compressive stress

Engineering Contradiction:

Improvestrength propertyVSAvoidnatural explosion risk

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

Different central tension values are applied to different regions of the cover window. The folding area has a first central tension value optimized for flexibility and repeated folding, while the non-folding area has a second central tension value optimized for strength and impact resistance. This local differentiation prevents excessive compressive stress in any single region, eliminating the natural explosion risk while maintaining overall strength.

Inventive Principle:

Principle #3Local quality

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 solution provides a flexible cover window with enhanced strength and folding properties, maintaining the intrinsic texture of glass, while minimizing breakage and waviness, and ensuring high transmittance and impact resistance, thus improving product quality and visibility.

Implementation Method 1

the chemical tempering treatment is performed to reinforce basic folding properties and strength, and a central tension (CT) value according to the chemical tempering treatment as a basic required physical property is around 30 MPa to 300 MPa

Methodology Applied

Scientific EffectChemical tempering:

Data Source

PatentUS11780771B2Flexible cover window having folding part and manufacturing method of same

Publication Date: 2023.10.10 UTI INC

AI summary

Proposed is a flexible cover window having a folding part, the cover window being a glass-based cover window for a flexible display and including: a plane part provided by corresponding to a plane area of the display, and a folding part provided by continuing to the plane part, by corresponding to a folding area of the display, and by being slimmed to be thinner than the plane part, wherein a depth of layer (DOL) of the plane part is larger than a depth of layer (DOL) of the folding part.