Liquid Crystal Display Thermal Expansion Management

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Solution Overview

Problem

Liquid crystal display devices face issues with uneven cell gaps due to thermal expansion of liquid crystal molecules, leading to deteriorated display quality, as existing techniques fail to effectively manage thermal expansion differences between various optical elements.

Innovation Solution

The implementation of a liquid crystal display device structure with specific thermal expansion coefficients for different members, including a first member with a lower coefficient of thermal expansion and a second member with a higher coefficient, along with a cover member for rigidity, to suppress thermal expansion and maintain even cell gaps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If optical elements with different coefficients of thermal expansion are disposed on the back of the display panel, then the display device can achieve functional requirements, but thermal expansion differences cause warpage and uneven cell gaps at high temperature

Engineering Contradiction:

Improvefunctional requirements of optical elementsVSAvoidcell gap uniformity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies thermal expansion principles by strategically selecting materials with specific coefficients of thermal expansion. The adhesive layer has a coefficient of thermal expansion positioned between those of the display panel and optical elements, allowing it to accommodate thermal expansion differences without transmitting warpage forces to the liquid crystal layer, thus maintaining cell gap uniformity while supporting multiple optical elements.

Inventive Principle:

Principle #37Thermal expansion

Solution Approach 2:

The adhesive layer serves as an intermediary element between the display panel and the optical elements. It has intermediate thermal expansion properties that allow it to absorb and dissipate thermal expansion stresses, preventing direct transmission of warpage forces to the liquid crystal layer while still providing necessary structural support.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If the cell gap is maintained even at high temperature, then display quality is maintained, but this requires suppressing thermal expansion of liquid crystal molecules

Engineering Contradiction:

Improvecell gap uniformityVSAvoidthermal expansion of liquid crystal molecules

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The patent converts the harmful thermal expansion of liquid crystal molecules into a beneficial effect. By allowing controlled expansion through the adhesive layer's intermediate thermal properties, the system actually benefits from the thermal expansion force to maintain even cell gaps, transforming what would be a harmful effect into a useful mechanism for preventing warpage.

Inventive Principle:

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

3Stability of the object's composition

If existing techniques are used to adhere antiwarp layer to light incident surface, then warpage of optical sheets is reduced, but thermal expansion differences between members cause display quality deterioration

Engineering Contradiction:

Improvewarpage reduction of optical sheetsVSAvoiddisplay quality

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent changes the thermal expansion parameter of the adhesive layer to be intermediate between the display panel and optical elements. This parameter change allows the adhesive layer to independently manage thermal expansion, providing warpage reduction while maintaining display quality through controlled thermal behavior.

Inventive Principle:

Principle #35Parameter changes

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 effectively suppresses the expansion of the display panel, maintaining even cell gaps and improving display quality by managing thermal expansion forces, and allows for a wider margin in the amount of liquid crystal material during manufacturing, reducing the risk of air bubbles and uneven displays.

Implementation Method 1

a coefficient of thermal expansion of the second member is greater than that of the first member

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10295729B2Liquid crystal display device

Publication Date: 2019.05.21 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, a liquid crystal display device includes a display device with a first main surface and a second main surface which is opposite to the first main surface, a first member disposed in the first main surface side of the display panel, a second member disposed between the first member and the display panel, and a cover member disposed in the second main surface side of the display panel, and having a rigidity greater than that of the display panel. The coefficient of thermal expansion of the second member is greater than that of the first member.