Drain Extension Line for IPS Display Light Leakage

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Solution Overview

Problem

In multi-domain liquid crystal display devices, such as VA, FFS, and IPS modes, the disordered electric field at domain boundaries leads to light leakage and reduced aperture ratio, which affects the display performance.

Innovation Solution

The array substrate design includes drain extension lines between sub-pixel units, acting as a light-blocking strip to prevent light leakage and overlapping with common electrode lines to form a storage capacitor, enhancing electrical coupling and capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multi-domain design is adopted to increase viewing angle, then viewing angle is improved, but light leakage occurs at domain boundaries due to disordered electric field

Engineering Contradiction:
Improveviewing angleVSAvoidlight leakage
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A light-blocking strip is introduced as an intermediary element at the domain boundary between adjacent pixel units. This light-blocking strip acts as a mediator that prevents light leakage caused by the disordered electric field at the domain boundary, while allowing the multi-domain design to maintain its wide viewing angle advantage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If light-blocking strip is added to prevent light leakage, then light leakage is reduced, but aperture ratio is reduced due to additional structure

Engineering Contradiction:
Improvelight leakageVSAvoidaperture ratio
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The light-blocking function is applied locally only at the domain boundaries where light leakage occurs, rather than across the entire pixel structure. The light-blocking strip is positioned specifically at the boundary between adjacent pixel units, maintaining local quality control and minimizing impact on the overall aperture ratio.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The light-blocking strip is designed with asymmetric positioning and dimensions, being located only at the domain boundary rather than symmetrically across the entire pixel structure. This asymmetric design allows the light-blocking function to be performed while minimizing the area occupied, thereby reducing the impact on aperture ratio.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If common electrode line is overlapped with drain extension line to form storage capacitor, then electrical coupling and capacitance are improved, but device complexity increases

Engineering Contradiction:
Improveelectrical couplingVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The common electrode line is designed to serve multiple functions: it acts as both the common electrode for the liquid crystal display and forms a storage capacitor with the drain extension line. This multi-functional design improves electrical coupling and capacitance without requiring separate dedicated structures, thereby avoiding significant increases in device complexity.

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

Solution Approach 2:

The storage capacitor function is merged with the common electrode line structure by overlapping the drain extension line with the common electrode line. This combining of functions into a single structural arrangement improves electrical coupling while avoiding the need for additional separate capacitor structures, thus limiting the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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

This design effectively blocks light leakage and increases the viewing angle by improving electrical coupling and capacitance, thereby enhancing the display performance and aperture ratio.

Implementation Method 1

the drain extension line can be used as a light-blocking strip to prevent light leakage

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Implementation Method 2

the drain extension line can also be overlapped with the middle portion of the common electrode line to form a storage capacitor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3705935B1Array substrate and manufacturing method therefor, and display device and manufacturing method therefor
Publication Date: 2023.11.01 BOE TECHNOLOGY GROUP CO LTD
  • EP3705935B1 patent drawingFigure 1
  • EP3705935B1 patent drawingFigure 2~3
  • EP3705935B1 patent drawingFigure 4

AI summary

The present disclosure provides an array substrate and a method for manufacturing the same, a display device and a method for manufacturing the same, and belongs to the field of display technology, which can solve the problem that a disordered electric field at the boundary between domains in an existing multi-domain design is likely to cause light leakage or a decrease in aperture ratio. In the array substrate of the present disclosure, the drain of the thin film transistor is extended to form a drain extension line, wherein the drain extension line is between adjacent sub-pixel units of the pixel region, thus it can block the light at the boundary between the sub-pixel units, thereby avoiding light leakage duo to the disordered electric field at the boundary between the sub-pixel units. The array substrate of the present disclosure is suitable for a multi-domain oriented IPS mode array substrate. On one hand, the drain extension line can be used as a light blocking strip to prevent light leakage due to the disordered electric field at the boundary between the sub-pixels, on the other hand, the drain extension line can also be overlapped with the middle portion of the common electrode line to form a storage capacitor.