TFT Display Shield Layer for Luminance Consistency

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Solution Overview

Problem

In organic light-emitting display apparatuses, the luminance of sub-pixels can vary due to differences in received data signals, leading to deteriorated image quality.

Innovation Solution

Incorporating a shield layer between the data line and components of the thin-film transistor (TFT) and integrating the shield layer with the storage capacitor plates to reduce parasitic capacitance and stabilize the electric potential of the TFTs, thereby maintaining consistent luminance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If data line is placed in a different layer from TFT components to enable signal transmission, then device integration is improved, but parasitic capacitance increases causing luminance inconsistency

Engineering Contradiction:
Improvelayer structureVSAvoidluminance consistency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A shield layer is introduced as an intermediary component between the data line and TFT components (source electrode, drain electrode, gate electrode). This shield layer acts as a mediator that blocks parasitic capacitance coupling while allowing the data line to remain in a different layer for signal transmission, thus resolving the contradiction between device integration and luminance consistency.

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 specifically targets and blocks the parasitic capacitance between the data line and TFT components, separating the signal transmission function from the parasitic interference, thereby maintaining luminance consistency without compromising device integration.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If shield layer is added between data line and TFT components to reduce parasitic capacitance, then luminance consistency is improved, but device structure complexity increases

Engineering Contradiction:
Improveluminance consistencyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shield layer is merged with existing capacitor electrode structures. Specifically, the shield layer is integrated with either the first capacitor electrode or the second capacitor electrode, allowing it to serve dual functions: blocking parasitic capacitance from the data line and maintaining capacitor functionality. This merging approach improves luminance consistency without significantly increasing overall device structure complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shield layer is designed to perform multiple functions simultaneously: it blocks parasitic capacitance between the data line and TFT components, and it is integrated with capacitor electrodes to maintain or enhance storage capacitance functionality. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device structure complexity while achieving luminance consistency.

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 shield layer stabilizes the electric potential of TFTs, ensuring consistent luminance and improving the overall quality of the displayed image by reducing the impact of parasitic capacitance from adjacent signal lines.

Implementation Method 1

In an organic light-emitting display apparatus, thin-film transistors (TFTs) may be located in each (sub) pixel to control the luminance of each (sub) pixel. However, luminance realized in a (sub) pixel of a general display apparatus may be different from that depending on a received data signal.

Methodology Applied
Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentEP3872860B1Display apparatus
Publication Date: 2026.03.11 SAMSUNG DISPLAY CO LTD
  • EP3872860B1 patent drawingFigure 1
  • EP3872860B1 patent drawingFigure 2
  • EP3872860B1 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.