Electro-Optic Sealing Layers Preventing Light Emitting Element Deterioration

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Solution Overview

Problem

Existing organic electroluminescence (EL) devices face challenges in completely blocking moisture due to cracks in the inorganic compound films used for sealing, which can lead to long-term reliability issues under external stress such as heat or pressure.

Innovation Solution

The electro-optic device incorporates a planarization layer and inorganic sealing layers with their outer edges positioned away from segmentation lines, reducing stress-induced defects and enhancing the barrier against moisture and oxygen infiltration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inorganic compound film and thermosetting resin are alternately laminated to block moisture, then the barrier performance is improved, but the flexibility decreases and cracks are more likely to generate under stress

Engineering Contradiction:

Improvemoisture blocking performanceVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent uses a composite sealing structure with multiple inorganic compound films (silicon oxide, silicon nitride, silicon oxynitride) and organic resin layers alternately laminated. This composite structure achieves both high moisture blocking performance and improved flexibility compared to single-material films, resolving the contradiction between barrier performance and mechanical flexibility.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the multilayer film and sealing film are formed across segmentation lines to provide complete coverage, then the sealing performance is improved, but stress concentration at segmentation lines increases crack likelihood

Engineering Contradiction:

Improvesealing performanceVSAvoidstress concentration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different sealing configurations to different regions: the sealing film covers the light-emitting element area for moisture blocking, but intentionally stops before reaching the segmentation lines. This local differentiation maintains sealing performance where needed while avoiding stress concentration at segmentation lines, preventing cracks.

Inventive Principle:

Principle #3Local quality

3Reliability

If the inorganic compound film is used as a rigid barrier layer, then the moisture blocking capability is improved, but the film becomes more susceptible to cracking under external stress

Engineering Contradiction:

Improvemoisture barrier capabilityVSAvoidfilm integrity under stress

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent creates a composite sealing film combining rigid inorganic compound films (providing moisture barrier) with flexible organic resin layers (providing stress absorption). This composite structure maintains moisture blocking capability while improving overall film integrity under external stress through the flexible component.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10164215B2Electro-optic device that prevents deterioration of a light emitting element

Publication Date: 2018.12.25 SEIKO EPSON CORP

AI summary

An electro-optic device includes a substrate that has a first surface and an end face crossing the first surface; a light emitting element that is disposed on the first surface; a planarization layer that covers the light emitting element; and a first inorganic sealing layer that is disposed on the planarization layer. An outer edge of the first inorganic sealing layer is disposed between an outer edge of the planarization layer and a first region where the light emitting element is disposed.