Light-Emitting Device Sealing via Pressed Bonding Layer

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Solution Overview

Problem

Organic electroluminescence (EL) elements in light-emitting devices are prone to reliability issues due to the entry of impurities like moisture and oxygen, which shorten their lifespan, and existing sealing techniques are inadequate in preventing such ingress.

Innovation Solution

A manufacturing method for light-emitting devices that includes forming a light-emitting portion with a spacer and an inorganic insulating layer, and a non-light-emitting portion with a frame-like shape, where the bonding layer is cured and then subjected to pressure with a projection to create a thinner region, reducing impurity entry and enhancing the device's reliability and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing sealing techniques are used to prevent impurity entry, then some protection is provided, but the sealing is inadequate and impurities still enter the organic EL element

Engineering Contradiction:

Improvesealing effectivenessVSAvoidimpurity entry

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sealing structure is divided into multiple functional layers: a bonding layer for attachment, an inorganic insulating layer with frame-like shape for primary sealing and mechanical support, and a spacer for maintaining gaps. This segmented approach provides comprehensive protection against impurity entry that single-layer sealing cannot achieve.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sealing system combines multiple materials with complementary properties: resin-based bonding layer for adhesion, inorganic insulating material for barrier properties and structural integrity, and spacer material for mechanical support. This composite structure achieves superior sealing effectiveness compared to any single material.

Inventive Principle:

Principle #40Composite materials

2Weight of moving object

If the device is made thin and lightweight, then flexibility and portability improve, but the device becomes more susceptible to breaking and impurity entry

Engineering Contradiction:

Improvedevice weightVSAvoidimpact resistance

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The inorganic insulating layer is configured with a frame-like shape that provides enhanced mechanical strength and protection at critical edges and corners where the device is most susceptible to damage. This localized reinforcement maintains overall device thinness while improving impact resistance at vulnerable points.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The spacer and inorganic insulating layer are positioned beforehand to create protective gaps and structural support before impurity entry or damage can occur. This preventive structural design cushions the organic EL element against mechanical stress and impurity ingress.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a thicker bonding layer is used to improve sealing, then impurity protection improves, but the device thickness increases and flexibility decreases

Engineering Contradiction:

Improvesealing performanceVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The sealing function is segmented across multiple thin layers rather than concentrated in one thick layer. The bonding layer provides attachment, the inorganic insulating layer provides barrier sealing, and the spacer provides mechanical support. This segmentation achieves effective sealing with minimal total thickness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bonding layer uses resin-based flexible material that provides effective sealing in a thin film form. This flexible thin film achieves adequate sealing performance without requiring excessive thickness, maintaining device flexibility and thinness.

Inventive Principle:

Principle #30Flexible shells and thin films

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 method improves the reliability and yield of light-emitting devices by minimizing impurity entry, allowing for the use of resins as bonding layers while maintaining high impact resistance and flexibility, and extending the devices' lifespan.

Implementation Method 1

a fourth step of curing the bonding layer

Methodology Applied

Scientific EffectCuring: Chemical Bonding

Implementation Method 2

applying pressure to at least a portion of a non-light-emitting portion with a member having a projection while heating the bonding layer after curing the bonding layer

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS11411208B2Manufacturing method of light-emitting device, light-emitting device, module, and electronic device

Publication Date: 2022.08.09 SEMICON ENERGY LAB CO LTD

AI summary

A highly reliable light-emitting device is provided. A yield in a manufacturing process of a light-emitting device is increased. A light-emitting device is provided in which a non-light-emitting portion having a frame-like shape outside a light-emitting portion includes a portion thinner than the light-emitting portion. A light-emitting element and a bonding layer are formed over a substrate. The light-emitting element is sealed by overlapping a pair of substrates and curing the bonding layer. Then, while the cured bonding layer is heated, pressure is applied to at least a portion of the non-light-emitting portion with a member having a projection.