Non-doping Blue OLED Layer for Thermal Protection

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Solution Overview

Problem

Conventional organic light emitting displays with a blue common layer structure face issues of reduced luminous efficiency and shortened lifespan due to the vulnerability of blue organic emission layers to heat transfer during laser-induced thermal imaging, requiring higher driving voltages for red and green layers.

Innovation Solution

A method involving a non-doping blue organic emission layer formed between the blue organic emission layer and the electron auxiliary layer, allowing smooth electron injection and reducing driving voltage, thereby enhancing luminous efficiency and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a blue organic emission layer is formed using laser induced thermal imaging, then the emission layer can be precisely patterned, but the blue organic emission layer is vulnerable to heat transfer and may be vacuum deposited on a larger surface than intended

Engineering Contradiction:

Improvepattern precisionVSAvoidheat transfer damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A non-doping blue organic emission layer is introduced as an intermediary layer between the electron auxiliary layer and the doped blue organic emission layer. This intermediary layer acts as a thermal buffer that protects the blue organic emission layer from direct heat transfer during laser induced thermal imaging, preventing vacuum deposition on unintended areas while maintaining precise patterning capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a blue common layer structure is used, then blue organic emission layer can be shared across multiple pixels, but red and green organic emission layers require higher driving voltages due to the presence of the blue organic emission layer

Engineering Contradiction:

Improvelayer structure simplificationVSAvoiddriving voltage

Core Design Contradiction:

Device complexityVSPower

Solution Approach 1:

The blue organic emission layer structure is differentiated into two regions: a non-doping blue organic emission layer in contact with the electron auxiliary layer, and a doped blue organic emission layer in contact with the red and green organic emission layers. This local quality differentiation allows the non-doping region to provide optimal electron injection for low driving voltage, while the doped region maintains the blue common layer structure for device simplification.

Inventive Principle:

Principle #3Local quality

3Reliability

If a doped blue organic emission layer is used directly on the electron auxiliary layer, then electron injection can occur, but luminous efficiency decreases and lifespan is deteriorated due to heat transfer vulnerability

Engineering Contradiction:

Improvedevice lifespanVSAvoidluminous efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The non-doping blue organic emission layer is positioned beforehand between the electron auxiliary layer and the doped blue organic emission layer to cushion against heat transfer during manufacturing and operation. This prior cushioning protects the doped blue organic emission layer from thermal damage, preventing luminous efficiency degradation and extending device lifespan while maintaining electron injection capability through the non-doping layer.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 solution increases luminous efficiency and extends the lifespan of organic light emitting displays by reducing driving voltage and minimizing thermal damage during the manufacturing process.

Implementation Method 1

a non-doping blue organic emission layer disposed on the blue organic emission layer; an electron auxiliary layer disposed on the non-doping blue organic emission layer

Methodology Applied

Scientific EffectElectron injection:

Implementation Method 2

Laser induced thermal imaging (LITI) is a laser addressed thermal patterning technique for exposing a mask pattern with a laser beam to generate a patterned laser beam that is irradiated onto a donor film

Methodology Applied

Scientific EffectLaser induced thermal imaging: Laser

Implementation Method 3

Exposed regions of the transfer layer may be released from the transfer layer, and, thereby, adhered to a portion of the organic light emitting display to form an emission layer

Methodology Applied

Scientific EffectThermal transfer: Conduction (thermal)

Data Source

PatentUS9165981B2Organic light emitting display and method of manufacturing the same

Publication Date: 2015.10.20 SAMSUNG DISPLAY CO LTD

AI summary

An organic light emitting display includes a substrate; a first pixel electrode disposed on the substrate; a second pixel electrode disposed on the substrate; a hole auxiliary layer disposed on the first pixel electrode and the second pixel electrode; a first organic emission layer disposed on the hole auxiliary layer in correspondence with the first pixel electrode and the second pixel electrode; a blue organic emission layer disposed on the hole auxiliary layer in correspondence with the first pixel electrode and the second pixel electrode, the blue organic emission layer being further disposed on the first organic emission layer; a non-doping blue organic emission layer disposed on the blue organic emission layer; an electron auxiliary layer disposed on the non-doping blue organic emission layer; and a common electrode disposed on the electron auxiliary layer.