OLED TFT Shield Layer Layout for Luminance Uniformity

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Solution Overview

Problem

The luminance of sub-pixels in organic light-emitting displays can vary due to differences in data signals, leading to deteriorated image quality.

Innovation Solution

The display apparatus incorporates a shield layer between signal lines and TFTs to reduce parasitic capacitance and maintain consistent luminance by shielding the TFTs from adjacent signal line variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If TFTs are located in each sub-pixel to control luminance, then luminance control capability is improved, but luminance uniformity deteriorates due to parasitic capacitance from adjacent signal lines

Engineering Contradiction:
Improveluminance control capabilityVSAvoidluminance uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

A shield layer is introduced as an intermediary component between the TFT and adjacent signal lines. This shield layer acts as a mediator that blocks parasitic capacitance coupling from signal lines to the TFT, thereby maintaining luminance uniformity while preserving the luminance control capability provided by the TFT in each sub-pixel.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful parasitic capacitance effect is extracted and isolated by introducing a dedicated shield layer. The shield layer captures and contains the parasitic capacitance interference, preventing it from affecting the TFT operation and thus maintaining both luminance control and uniformity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If shield layers are added to reduce parasitic capacitance, then luminance uniformity is improved, but device complexity increases

Engineering Contradiction:
Improveluminance uniformityVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The shield layer is implemented as a thin film structure that can be integrated into the existing display device architecture. This thin film approach provides the necessary shielding function against parasitic capacitance while minimizing the increase in device complexity and maintaining compatibility with existing manufacturing processes.

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If shield layers are added to reduce parasitic capacitance, then image quality is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveimage qualityVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The shield layer is formed as a thin film that can be integrated using existing thin film deposition techniques. This approach improves image quality by reducing parasitic capacitance effects while maintaining compatibility with current manufacturing processes, thus limiting the increase in manufacturing complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The shield layer serves multiple functions: it reduces parasitic capacitance from adjacent signal lines, maintains luminance uniformity, and can be integrated with existing device structures. This multi-functionality improves image quality while minimizing the impact on manufacturing simplicity by consolidating multiple benefits into a single component.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 ensures consistent luminance across sub-pixels, enhancing the overall image quality by minimizing the impact of adjacent signal line variations on TFTs.

Implementation Method 1

a shield layer disposed between the data line and a part between the first gate electrode and the second gate electrode of the initialization TFT

Methodology Applied
Scientific EffectElectrostatic shielding: Faraday Cage

Data Source

PatentEP3872859B1Display apparatus
Publication Date: 2026.02.11 SAMSUNG DISPLAY CO LTD
  • EP3872859B1 patent drawingFigure 1
  • EP3872859B1 patent drawingFigure 2
  • EP3872859B1 patent drawingFigure 3

AI summary

A display apparatus includes: a thin-film transistor including a source electrode, a drain electrode, and a gate electrode; a data line in a layer different from the source electrode, the drain electrode, and the gate electrode, wherein the data line is configured to transmit a data signal; and a shield layer between the data line and a component of the thin-film transistor.