Flexible Electronic Device Package with Segmented Sealing Member

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Solution Overview

Problem

Current packaging technologies for flexible organic electroluminescent elements face challenges in balancing flexural properties, gas barrier properties, and processing convenience, as thermal curing adhesives cause stress and damage when removing the packaged elements from rigid substrates and have poor flexural properties suitable for flexible devices.

Innovation Solution

A flexible environmental sensitive electronic device package is designed with a thin film encapsulation and a sealing member having distinct portions, where the first portion provides gas barrier properties and the second portion offers stress buffer capabilities, with Young's modulus and thickness optimized to minimize stress and ensure easy removal at room temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal curing adhesive is used for packaging flexible organic electroluminescent elements, then gas barrier properties are improved, but flexural properties deteriorate and stress damage occurs during removal from rigid substrates

Engineering Contradiction:

Improvegas barrier propertiesVSAvoidflexural properties

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The sealing adhesive is divided into two distinct portions: a first portion that contacts the thin film encapsulation and a second portion that contacts the flexible cover board. This segmentation allows each portion to have optimized properties for its specific function, resolving the contradiction between gas barrier performance and flexural flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the sealing adhesive are assigned different Young's modulus values and thicknesses. The first portion has higher Young's modulus (50-500 MPa) and smaller thickness (1-10 μm) for gas barrier function, while the second portion has lower Young's modulus (0.1-10 MPa) and larger thickness (5-20 μm) for flexural function. This local differentiation resolves the contradiction by optimizing each region for its specific requirement.

Inventive Principle:

Principle #3Local quality

2Reliability

If thermal curing adhesive is used to ensure gas barrier properties, then moisture and oxygen penetration is reduced, but stress generated during packaging causes damage to the flexible element when removed from rigid substrate

Engineering Contradiction:

Improveprotection against moisture and oxygen penetrationVSAvoidstress resistance during removal from substrate

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The sealing adhesive is segmented into two portions with different mechanical properties. The first portion provides strong adhesion and gas barrier for protection, while the second portion provides stress buffering with lower modulus to prevent damage during substrate removal, resolving the contradiction between protection strength and stress resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sealing adhesive functions as a composite structure with two portions having different material characteristics. The first portion (higher modulus) provides structural integrity and barrier function, while the second portion (lower modulus) provides stress absorption, creating a composite system that achieves both protection and stress resistance.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If uniform thickness sealing adhesive is used, then manufacturing process is simplified, but it cannot simultaneously provide optimal gas barrier properties and stress buffer capabilities

Engineering Contradiction:

Improveprocess simplicityVSAvoidsimultaneous gas barrier and stress buffer performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Instead of uniform thickness, the sealing adhesive employs local quality differentiation where the first portion has smaller thickness (1-10 μm) optimized for gas barrier properties and the second portion has larger thickness (5-20 μm) optimized for stress buffer capabilities. This resolves the contradiction by allowing each region to have the specific thickness needed for its function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The sealing adhesive is segmented into two portions with different thicknesses to simultaneously achieve gas barrier and stress buffer functions. This segmentation allows optimization of each portion's thickness for its specific purpose, resolving the contradiction between manufacturing simplicity and multi-functional performance.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9847509B2Package of flexible environmental sensitive electronic device and sealing member

Publication Date: 2017.12.19 HANNSTAR DISPLAY CORP

AI summary

A flexible environmental sensitive electronic device package including a flexible electronic device, a thin film encapsulation (TFE) and a sealing member is provided. The TFE covers the flexible electronic device as well as the sealing member covers the TFE and the flexible electronic device. The sealing member includes a first portion and a second portion, wherein the first portion covers the flexible electronic device and the TFE, and the second portion covers the first portion. Young's modulus of the second portion is between the 0 MPa and 100 MPa. Young's modulus of the first portion is greater than that of the second portion. The thickness of the first portion is less than that of the second portion.