Mitigating Pooling Mura in Pressed LCD Pixel Electrodes

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

LCD apparatuses suffer from pooling mura, which causes display anomalies and user confusion due to white or black trailing smears when pressed, leading to incorrect assumptions about panel damage.

Innovation Solution

The method involves adjusting the original display data for pressed pixels to rotate liquid crystal molecules toward a natural angle, either by altering voltage levels or coupling pixel electrodes to a predetermined potential, and using touch panels to detect press locations and implement these adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If external force is applied to the LCD panel to perform touch operation, then touch input can be detected, but white or black trailing smear is formed and pooling mura occurs

Engineering Contradiction:

Improvetouch operationVSAvoiddisplay quality

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by detecting the touch pressure direction before the liquid crystal molecules complete their alignment change. When pressure is detected on the pixel electrode, the system proactively adjusts the driving voltage to compensate for the impending molecular reorientation, preventing the formation of trailing smear before it occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring the pressure state on pixel electrodes and dynamically adjusting the driving voltage based on real-time pressure detection. The system uses the pressure direction information to modulate the voltage applied to liquid crystal molecules, creating a closed-loop control system that prevents pooling mura formation.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If the applied external force is larger, then the touch operation can be detected more accurately, but the area of white trailing smear is larger

Engineering Contradiction:

Improvetouch location detectionVSAvoidtrailing smear area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the driving voltage parameter based on the detected pressure magnitude. When larger pressure is detected, the system increases the compensatory voltage adjustment to counteract the stronger force that causes greater molecular displacement, thereby maintaining consistent trailing smear area across different pressure levels while preserving touch detection accuracy.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the trailing smear distance is too long, then users can easily detect the press location, but users may mistake the panel for damaged

Engineering Contradiction:

Improvepress location detectionVSAvoiduser confusion

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of pressure-induced molecular displacement into a beneficial feature by using the pressure detection information to actively compensate for the alignment change. Instead of allowing the trailing smear to form naturally, the system uses the pressure signal to adjust the driving voltage in real-time, transforming what would be a display defect into a controlled response that maintains normal display appearance while preserving touch sensitivity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach effectively mitigates pooling mura by allowing LCDs to maintain normal frame display even when pressed, reducing user inconvenience and eliminating mistaken damage assessments.

Implementation Method 1

each of at least a part of the pixels comprises two pixel electrodes to drive a plurality of liquid crystal molecules sandwiched between the two pixel electrodes

Methodology Applied

Scientific EffectLiquid crystal molecules alignment: Liquid Crystals

Implementation Method 2

changing a corresponding portion of the original display data which is initially for driving a pressed pixel at a pressed location, so as to rotate at least a part of the liquid crystal molecules sandwiched between the two pixel electrodes of the pressed pixel toward a natural angle

Methodology Applied

Scientific EffectElectric field effect on liquid crystal orientation: Electric Field

Data Source

PatentUS8581878B2Method for mitigating pooling mura on liquid crystal display apparatus and liquid crystal display apparatus

Publication Date: 2013.11.12 AU OPTRONICS CORP

AI summary

A method for mitigating pooling mura on LCD apparatus and a LCD apparatus are provided. The method is adapted for a LCD apparatus having a plurality of pixels. The LCD apparatus is for displaying frames according to a received original display data, and each of at least a part of the pixels comprises two pixel electrodes to drive a plurality of liquid crystal molecules between the two pixel electrodes. The method comprises changing a corresponding portion of the original display data so as to rotate at least a part of the liquid crystal molecules between the two pixel electrodes of the pressed pixel toward a natural angle; and maintaining another corresponding portion of the original display data. The natural angle is a finally-presented tilt angle of the liquid crystal molecules between the corresponding two pixel electrodes having substantially no potential difference therebetween.