OLED Light-Blocking Layer UV Protection

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Solution Overview

Problem

Organic light-emitting diode (OLED) devices suffer performance degradation and picture quality deterioration due to ultraviolet (UV) light exposure, which affects the valence band electrons and forbidden band gap, leading to increased threshold voltage and reduced ON/OFF ratio.

Innovation Solution

Incorporating a light-blocking layer, made of materials like ZnO, IGZO, TiO2, or TiO2, between the organic light-emitting layer and the cathode, or at the light-exiting side of the OLED device to block UV light, thereby preventing performance degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a light-blocking layer is added to block UV light, then the reliability of the OLED device is improved, but the device complexity increases

Engineering Contradiction:

ImproveOLED device stabilityVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a light-blocking layer as an intermediary component between the organic light-emitting layer and the electrode. This layer specifically blocks UV light while allowing visible light to pass through, thereby protecting the OLED device from UV damage without affecting its display function. The light-blocking layer acts as a mediator that filters harmful radiation while maintaining the device's operational performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite material structures by combining the light-blocking layer with existing OLED components such as the organic light-emitting layer, electron transport layer, and electrode. This creates a multi-functional composite structure where each layer contributes specific properties: the light-blocking layer provides UV protection, while the other layers maintain electroluminescence and charge transport functions.

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If a light-blocking layer is added to block UV light, then the durability of the OLED device is improved, but the manufacturing process complexity increases

Engineering Contradiction:

ImproveOLED device lifespanVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The light-blocking layer is incorporated into the OLED device structure during the manufacturing process, before the device is put into service. This preliminary incorporation ensures that UV protection is built-in from the outset, preventing cumulative UV damage throughout the device's operational life. The layer is deposited or formed as part of the standard fabrication sequence, ensuring long-term durability without requiring post-manufacturing modifications.

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If the light-blocking layer is positioned at the light-exiting side, then the UV protection effectiveness is improved, but the visual light transmission may be affected

Engineering Contradiction:

ImproveUV light blocking effectivenessVSAvoidvisible light transmission

Core Design Contradiction:

Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The light-blocking layer exhibits selective optical properties with different transmission characteristics for different wavelengths of light. It has high absorption or reflection for UV wavelengths (below 400 nm) while maintaining high transparency for visible wavelengths (400-700 nm). This local quality differentiation allows the same material layer to provide effective UV protection without compromising the display brightness and visual quality of the OLED device.

Inventive Principle:

Principle #3Local quality

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 light-blocking layer effectively prevents UV-induced performance degradation, maintaining the stability and reliability of OLED devices by absorbing UV radiation without affecting visual light transmission.

Implementation Method 1

the light-blocking layer may be made of ZnO, IGZO, TiO2, SnO2, ITZO, AlZO, ZnSnO, HfInZnO, AZTO, AlZnSnO, or ZnON... the light-blocking layer effectively prevents UV-induced performance degradation, maintaining the stability and reliability of OLED devices by absorbing UV radiation

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS9905625B2Organic light-emitting diode (OLED) device and display device

Publication Date: 2018.02.27 BOE TECHNOLOGY GROUP CO LTD

AI summary

The present disclosure relates to an organic light-emitting diode (OLED) device and a display device. The OLED device may include a substrate, thin film transistors (TFTs), an anode, a cathode, and an organic light-emitting layer between the anode and the cathode and configured to emit light. The organic light-emitting layer may be provided with a light-blocking layer which is configured to block ultraviolet (UV) light and arranged at a light-exiting side of the organic light-emitting layer. The display device may include the OLED device.