LCD Panel HALS Alignment Layer Suppresses Ion Formation

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Solution Overview

Problem

Liquid crystal display (LCD) panels experience image sticking and flicker due to residual DC voltage, which affects the alignment of liquid crystals and leads to poor display quality, especially when showing still images for extended periods.

Innovation Solution

Incorporating liquid crystals with negative dielectric anisotropy and a hindered amine light stabilizer (HALS) along with an optical alignment layer, which suppresses ion formation and adjusts the alkoxy group content in the liquid crystal layer to minimize image sticking and flicker.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid crystal display panels are driven with AC voltage to prevent DC voltage accumulation, then image sticking is reduced, but residual DC voltage still accumulates due to parasitic capacitors causing image quality degradation

Engineering Contradiction:

Improveimage qualityVSAvoidresidual DC voltage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies a hindered amine light stabilizer (HALS) to the alignment layer, which captures and neutralizes the harmful ions generated by residual DC voltage. The HALS converts the harmful ion accumulation into a beneficial effect by preventing ion deposition on the alignment layer, thereby eliminating image sticking while maintaining AC voltage driving

Inventive Principle:

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

Solution Approach 2:

The HALS-coated alignment layer acts as an intermediary between the liquid crystal layer and the electrodes. It mediates the interaction by capturing ions before they can deposit on the alignment layer, thus preventing the harmful effects of residual DC voltage without changing the AC voltage driving mode

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If liquid crystals with negative dielectric anisotropy are used to reduce power consumption, then power efficiency improves, but ion formation increases leading to image sticking and flicker

Engineering Contradiction:

Improvepower consumptionVSAvoidion formation

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The HALS coating on the alignment layer captures the harmful ions generated by liquid crystals with negative dielectric anisotropy. This allows the system to maintain the power efficiency benefits of negative dielectric anisotropy liquid crystals while neutralizing the harmful ion formation that causes image sticking and flicker

Inventive Principle:

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

Solution Approach 2:

The patent changes the chemical composition parameter of the alignment layer by coating it with HALS. This parameter change enables the alignment layer to capture ions, thereby resolving the contradiction between using negative dielectric anisotropy liquid crystals for low power consumption and preventing ion-related display defects

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If alignment layer is made more susceptible to electrical stress to improve liquid crystal alignment, then alignment precision improves, but residual DC voltage accumulates more causing image sticking

Engineering Contradiction:

Improveliquid crystal alignmentVSAvoidresidual DC voltage accumulation

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The HALS-coated alignment layer serves as an intermediary that protects the alignment structure from ion damage. It maintains the alignment precision needed for proper liquid crystal orientation while preventing ion deposition that would otherwise accumulate due to electrical stress

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The HALS converts the harmful effect of electrical stress on the alignment layer into a beneficial outcome by capturing ions before they can deposit. This allows the alignment layer to maintain its precision function while the HALS neutralizes the harmful ion accumulation

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 configuration reduces image sticking and flicker, enhances voltage holding ratio, and increases transmissivity and contrast, while maintaining low power consumption.

Implementation Method 1

a hindered amine light stabilizer (HALS), which suppresses ion formation

Methodology Applied

Scientific EffectIon formation suppression:

Implementation Method 2

Liquid crystals may have dielectric anisotropy (e.g., may have a variable dielectric constant depending on the direction of alignment thereof)

Methodology Applied

Scientific EffectDielectric anisotropy: Dielectric Permittivity

Implementation Method 3

an optical alignment layer, which suppresses ion formation and adjusts the alkoxy group content in the liquid crystal layer

Methodology Applied

Scientific EffectOptical alignment:

Data Source

PatentUS10883049B2Liquid crystal display panel

Publication Date: 2021.01.05 SAMSUNG DISPLAY CO LTD

AI summary

A liquid crystal display (LCD) panel includes a first substrate, a second substrate, and a liquid crystal layer disposed between the first substrate and the second substrate. The liquid crystal layer includes liquid crystals with negative dielectric anisotropy and a hindered amine light stabilizer (HALS).