Flexible Substrate with Inorganic Buffer Layer for Display Fabrication

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Solution Overview

Problem

Existing flexible display apparatuses face challenges with low process accuracy due to warping of rigid auxiliary substrates caused by thermal expansion coefficient mismatches between flexible substrates and rigid substrates during fabrication.

Innovation Solution

A flexible substrate comprising a first organic layer, an inorganic buffer layer, and a second organic layer, where the inorganic buffer layer is between the first and second organic layers, and the second organic layer includes inorganic nano-particles, is used to reduce the thermal expansion coefficient mismatch and prevent warping of the rigid auxiliary substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flexible substrate is formed on a rigid auxiliary substrate during fabrication, then the flexible display apparatus can be manufactured, but warping occurs due to thermal expansion coefficient mismatch between the flexible and rigid substrates

Engineering Contradiction:

Improvefabrication processVSAvoidprocess accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

An inorganic buffer layer is introduced as an intermediary between the flexible substrate and the rigid auxiliary substrate. This buffer layer has a thermal expansion coefficient that is closer to that of the rigid substrate, thereby reducing the thermal expansion coefficient mismatch and preventing warping during high-temperature fabrication processes

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The flexible substrate is designed as a composite structure comprising multiple layers including organic layers and an inorganic buffer layer. This composite structure combines materials with different thermal expansion properties to achieve overall thermal stability and reduce warping while maintaining flexibility

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If the flexible substrate uses only organic materials, then flexibility is maintained, but thermal expansion coefficient mismatch with rigid substrates causes warping

Engineering Contradiction:

ImproveflexibilityVSAvoidprocess accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different layers of the flexible substrate are assigned different material compositions with specific thermal expansion properties. The inorganic buffer layer locally compensates for thermal expansion mismatch, while organic layers maintain flexibility, creating a functionally differentiated structure

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 proposed flexible substrate configuration reduces the risk of warping of the rigid auxiliary substrate, thereby improving the process accuracy and reducing errors during the fabrication of display devices, while also being suitable for high-temperature fabrication processes.

Implementation Method 1

warping of rigid auxiliary substrates caused by thermal expansion coefficient mismatches between flexible substrates and rigid substrates

Methodology Applied

Scientific EffectThermal expansion coefficient mismatch: Thermal Expansion

Data Source

PatentUS12295250B2Flexible substrate and fabrication method thereof, and flexible display apparatus

Publication Date: 2025.05.06 BOE TECHNOLOGY GROUP CO LTD

AI summary

The present disclosure provides a display device. The display device includes: a flexible substrate including a first organic layer, a second organic layer, and an inorganic layer sandwiched between the first organic layer and the second organic layer; an organic light emitting diode device on the flexible substrate, the organic light emitting diode device including an anode, a cathode and an organic light emitting layer between the anode and the cathode; and a flexible encapsulation layer on the organic light emitting diode device. A material of the first organic layer is the same as a material of the second organic layer, a thickness of the first organic layer is greater than a thickness of the second organic layer, and at least one of the first organic layer or the second organic layer includes inorganic nano-particles.