Dimming Substrate Structure for Thermal Warpage Reduction

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Solution Overview

Problem

Existing dimming substrates face warpage issues due to thermal shrinkage stress during the manufacturing process, particularly when using glass as a base material for large-curvature hyperbolic windows, where the difference in thermal shrinkage rates between rigid and flexible components leads to deformation of the rigid carrier plate.

Innovation Solution

A dimming substrate design featuring a rigid carrier plate, a bonding layer composed of one or more adhesive layers without flexible base films, a flexible base plate with controlled thermal shrinkage, and a stress buffer layer made from two-way memory alloy, which reduces thermal shrinkage stress and warpage by minimizing the difference in thermal expansion rates and providing a counteracting force during cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass is used as a rigid carrier plate for large-curvature hyperbolic windows, then the structural strength and rigidity are improved, but the thermal shrinkage stress during manufacturing causes warpage and deformation

Engineering Contradiction:

Improvestructural strengthVSAvoidwarpage control

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent divides the base plate into two distinct segments: a rigid carrier plate (glass) and a flexible base plate, each serving specific functions. The rigid carrier plate provides structural strength while the flexible base plate accommodates thermal shrinkage, thus preventing warpage of the rigid component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs a composite structure combining rigid glass carrier plate with flexible base plate materials (such as PI, PET, or PEN). This composite design allows the system to simultaneously achieve high structural strength from the glass and thermal shrinkage accommodation from the flexible material, resolving the contradiction between strength and manufacturing precision.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If a bonding layer with flexible base films is used to bond the rigid carrier plate, then the ease of manufacture is improved, but the thermal shrinkage rate difference causes warpage of the rigid carrier plate

Engineering Contradiction:

Improvebonding processVSAvoidcarrier plate deformation

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent extracts the flexible base films from the bonding layer, retaining only the adhesive layers. This removal eliminates the source of thermal shrinkage stress that causes warpage, while the bonding function is maintained through the adhesive layers alone, thus resolving the contradiction between ease of manufacture and structural stability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the thermal shrinkage parameter of the flexible base plate by selecting specific materials (PI, PET, PEN) with thermal shrinkage rates ≤0.01% in both machine and vertical directions. This parameter control ensures compatibility with the rigid carrier plate during cooling, preventing warpage while maintaining manufacturability.

Inventive Principle:

Principle #35Parameter changes

3Area of stationary object

If the flexible base plate has larger size to cover the rigid carrier plate, then the coverage and protection are improved, but the thermal shrinkage stress increases causing more warpage

Engineering Contradiction:

Improvecoverage areaVSAvoidthermal shrinkage stress

Core Design Contradiction:

Area of stationary objectVSStress or pressure

Solution Approach 1:

The patent applies local quality by making the flexible base plate smaller than the rigid carrier plate in both machine and vertical directions. This localized sizing ensures adequate coverage for the functional areas while minimizing the total area subject to thermal shrinkage, thus reducing overall stress and warpage.

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 effectively reduces warpage of the rigid carrier plate by minimizing thermal shrinkage stress and deformation, ensuring the dimming substrate maintains structural integrity and functionality, particularly suitable for large-curvature applications like automobile windows.

Implementation Method 1

the stress buffer layer is made from two-way memory alloy... configured to recover to a flat state corresponding to a low temperature during a high-temperature cooling process

Methodology Applied

Scientific EffectShape memory alloy effect: Shape Memory Alloy

Implementation Method 2

the bonding layer comprises one or more adhesive layers

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11828965B2Dimming substrate, manufacturing method thereof, dimming structure and dimming module

Publication Date: 2023.11.28 BEIJING BOE SENSOR TECH CO LTD

AI summary

The present disclosure provides a dimming substrate, a manufacturing method of the dimming substrate, a dimming structure and a dimming module, and relates to the technical field of display. According to the present disclosure, a bonding layer, a flexible base plate, an electrode layer and an orientation layer are sequentially arranged on a rigid carrier plate, and the bonding layer includes one or more adhesive layers. By removing flexible base films from the bonding layer, the bonding layer only includes one or more adhesive layers, such that the dimming substrate includes less flexible base films.