Light-Shielding Layer for OLED Array Substrates

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Solution Overview

Problem

The light emitted from White Organic Light-Emitting Diode (WOLED) devices, particularly blue light with a wavelength of 400nm or less, adversely affects the characteristics of thin-film transistors, leading to leakage currents and deteriorated display effects in OLED display devices.

Innovation Solution

An array substrate with a light-shielding layer is introduced above the thin-film transistor structure to block blue light, using filters such as red or green filters, or a laminated structure of red and green filters, to prevent blue light from entering the transistor region, while allowing longer wavelengths to transmit, thereby improving display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a light-shielding layer is added to block blue light from entering the thin-film transistor structure, then the display effect is improved and leakage current is reduced, but the device complexity increases

Engineering Contradiction:
Improvedisplay effectVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A light-shielding layer is introduced as an intermediary component between the organic light-emitting diode and the thin-film transistor structure. This layer selectively blocks blue light (wavelength ≤400nm) from reaching the transistor while allowing other wavelengths to pass through, thereby protecting the transistor from light-induced leakage current without fundamentally changing the device architecture

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The light-shielding layer is positioned specifically in the thin-film transistor structure region rather than uniformly across the entire device. This localized approach blocks harmful blue light only where it affects the transistor characteristics, while maintaining optical performance in the display region, thus resolving the contradiction between protection and complexity

Inventive Principle:
Principle #3Local quality

2Reliability

If the light-shielding layer is made thicker to improve blue light blocking, then the protection effect is enhanced, but the transmittance of other wavelengths is reduced

Engineering Contradiction:
Improveprotection effectVSAvoidtransmittance
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The light-shielding layer utilizes selective wavelength absorption characteristics by controlling its thickness parameter within the range of 5000Å-40000Å. This thickness range is optimized to provide sufficient blue light blocking capability while maintaining adequate transmittance for red and green wavelengths, thus resolving the contradiction between protection effect and overall transmittance

Inventive Principle:
Principle #35Parameter changes

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 implementation of a light-shielding layer effectively prevents blue light from impacting the thin-film transistors, enhancing transmittance and improving the display effect by maintaining the characteristics of the thin-film transistors and reducing leakage currents.

Implementation Method 1

a light-shielding layer is formed above the thin-film transistor structure in the thin-film transistor structure region, and the light-shielding layer is configured to block a blue light from entering the thin-film transistor structure

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

Organic Light-Emitting Diode (OLED) has the advantages of simple fabrication process, low cost, capable of adjusting color of the emitted light in the visible region

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3780111A1Array substrate and fabrication method thereof, display device
Publication Date: 2021.02.17 BOE TECHNOLOGY GROUP CO LTD
  • EP3780111A1 patent drawingFigure 1~2
  • EP3780111A1 patent drawingFigure 3~5
  • EP3780111A1 patent drawingFigure 6~7

AI summary

Embodiments of the invention disclose an array substrate and a fabrication method thereof, and a display device. The array substrate comprises a plurality of pixel units disposed on a base substrate, and the pixel unit comprises a thin-film transistor structure region and a display region other than the thin-film transistor structure region. A thin-film transistor structure is formed in the thin-film transistor structure region, an organic light-emitting diode is formed in the display region, and the thin-film transistor structure is configured to drive the organic light-emitting diode. A light-shielding layer is formed above the thin-film transistor structure in the thin-film transistor structure region, and the light-shielding layer is configured to block a blue light from entering the thin-film transistor structure.