Curved Light-Emitting Device Planarization Layer

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Solution Overview

Problem

Forming light-emitting devices with uniform thickness over curved surfaces is challenging due to variations in deposition rates and angles during methods like vacuum evaporation or sputtering, leading to uneven luminance and potential short circuits or non-light-emitting regions.

Innovation Solution

A substrate with plasticity is used to form a light-emitting element, which is then curved over a support, with a protective layer applied to maintain the shape and prevent impurity dispersion, utilizing a planarization layer and a glass-resin protective stack for enhanced heat dissipation and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If vacuum evaporation or sputtering method is used to form light-emitting devices over curved surfaces, then the device can be formed on curved surfaces, but the deposition rates and angles vary leading to uneven thickness and luminance

Engineering Contradiction:
Improvecurved surface applicabilityVSAvoidthickness uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by first forming a planarization layer over the curved substrate before depositing the light-emitting functional layers. This planarization layer pre-compensates for the curved surface topology, creating a flat deposition surface that ensures uniform thickness and luminance in the subsequent vacuum evaporation or sputtering processes.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If vacuum evaporation or sputtering method is used to form light-emitting devices over curved surfaces, then the device can be formed on curved surfaces, but uneven thickness causes electric-field concentration and short circuits

Engineering Contradiction:
Improvecurved surface applicabilityVSAvoidshort circuit prevention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The planarization layer is formed in advance to create a flat surface for subsequent layer deposition, preventing electric-field concentration that would otherwise occur at thickness variations. This preliminary surface preparation ensures uniform electric field distribution and prevents short circuits in the light-emitting device.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If coating method or printing method is used for deposition over curved surfaces, then uniform thickness can be achieved, but the apparatus structure becomes very difficult to implement

Engineering Contradiction:
Improvethickness uniformityVSAvoidapparatus structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a planarization layer as an intermediary between the curved substrate and the light-emitting functional layers. This intermediary layer simplifies the overall apparatus structure by enabling the use of standard vacuum evaporation or sputtering equipment, while still achieving uniform thickness through the planarization function of the intermediate layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This method allows for the creation of reliable light-emitting devices with uniform luminance and increased heat dissipation, suitable for curved applications like building or vehicle installations, while preventing impurity dispersion and mechanical failures.

Implementation Method 1

utilizing a planarization layer and a glass-resin protective stack for enhanced heat dissipation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10043989B2Light-emitting device and manufacturing method thereof
Publication Date: 2018.08.07 SEMICON ENERGY LAB CO LTD

AI summary

A light-emitting device having a curved light-emitting surface is provided. Further, a highly-reliable light-emitting device is provided. A substrate with plasticity is used. A light-emitting element is formed over the substrate in a flat state. The substrate provided with the light-emitting element is curved and put on a surface of a support having a curved surface. Then, a protective layer for protecting the light-emitting element is formed in the same state. Thus, a light-emitting device having a curved light-emitting surface, such as a lighting device or a display device can be manufactured.