Liquid Crystal Display Protrusions and Compensation Patterns

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Solution Overview

Problem

Liquid crystal display devices with column spacers suffer from touch failures due to high frictional forces and thermal expansion issues, leading to persistent stains and opaque areas.

Innovation Solution

The use of protrusions on the first substrate with corresponding compensation patterns on the second substrate, reducing frictional forces and maintaining contact with column spacers during thermal expansion, thereby preventing liquid crystal flow and substrate misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If column spacers are used to maintain cell gap, then cell gap stability is improved, but frictional force increases causing touch failure

Engineering Contradiction:

Improvecell gap stabilityVSAvoidfrictional force

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

The column spacer is divided into two functional parts: a support portion that contacts the protrusion to maintain cell gap, and a separate protrusion structure that reduces contact area with the substrate. This segmentation allows the spacer to maintain stability while reducing frictional force during touch operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the column spacer structure are given different properties: the support portion has sufficient height and contact area with the protrusion for stability, while the interface with the substrate is minimized through the protrusion design. This local differentiation resolves the contradiction between needing stability and minimizing friction.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If column spacers are used to maintain cell gap, then cell gap stability is improved, but thermal expansion causes liquid crystal flow and opaque areas

Engineering Contradiction:

Improvecell gap stabilityVSAvoidthermal expansion effects

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The protrusion structure is designed to maintain continuous contact with the column spacer's support portion, creating a constraint that prevents liquid crystal flow before thermal expansion can cause harmful effects. This preliminary constraint counteracts the potential damage from thermal expansion.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The protrusion acts as an intermediary element between the column spacer and the substrate, providing a mechanical constraint that prevents liquid crystal flow during thermal expansion. This intermediary structure absorbs the thermal stress and prevents it from causing opaque areas.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If large contact area between column spacers and substrate is used, then cell gap maintenance is improved, but touch-induced substrate shift increases

Engineering Contradiction:

Improvecell gap maintenanceVSAvoidtouch operation smoothness

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The contact interface is segmented into two distinct locations: a small contact area between the protrusion and substrate for easy touch operation, and a larger contact area between the column spacer support portion and protrusion for cell gap maintenance. This segmentation resolves the contradiction between ease of operation and cell gap stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different contact areas are given different functions: the protrusion-substrate interface has minimal contact area for smooth touch operation, while the column spacer-support portion interface has sufficient contact area for maintaining cell gap. This local quality differentiation allows both requirements to be satisfied simultaneously.

Inventive Principle:

Principle #3Local quality

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 effectively reduces touch-induced substrate shifts, prevents liquid crystal flow due to thermal expansion, and maintains stable cell gaps, reducing the occurrence of touch stains and opaque areas.

Implementation Method 1

reducing frictional forces and maintaining contact with column spacers during thermal expansion

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

maintaining contact with column spacers during thermal expansion, thereby preventing liquid crystal flow and substrate misalignment

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS7868994B2Liquid crystal display device and method for manufacturing the same

Publication Date: 2011.01.11 LG DISPLAY CO LTD

AI summary

A liquid crystal display device includes a first substrate and a second substrate facing each other, column spacers at designated areas of the second substrate, protrusions having a first height on the first substrate corresponding to portions of the column spacers, compensation patterns having a second height on the first substrate corresponding to the edges of the column spacers, the second height being lower than the first height, and a liquid crystal layer filling a gap between the first and second substrates.