Fluorine-Modified Black Matrix Ink Bleed Prevention

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Solution Overview

Problem

Ink bleed during the manufacturing of color filters for liquid crystal display devices occurs due to the hydrophilic nature of the ink, which affects the color properties and display quality by causing ink overflow beyond pixel areas.

Innovation Solution

A black matrix composition with high hydrophobicity is developed, containing 40 parts by weight of pigment dispersion, 0.1 to 1.0 part by weight of photoinitiator, 5 to 20 parts by weight of photo-polymerizable monomer, 5 to 20 parts by weight of binder resin, 0.1 to 0.5 parts by weight of epoxy-based monomer with fluorine, and 35 to 55 parts by weight of solvent, which forms a thermally cross-linked resin with fluorine exposure, preventing ink bleed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional hydrophilic ink is used in ink jetting process, then the ink can be easily injected into pixel area, but the ink overflows from pixel area to black matrix surface causing ink bleed

Engineering Contradiction:

Improveink injection easeVSAvoidink position control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The black matrix surface properties are changed by incorporating fluorine-containing compounds, which alters the surface energy and creates hydrophobicity. This parameter change in surface chemistry prevents ink overflow while maintaining proper ink injection into pixel areas.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The black matrix composition is formulated as a composite material containing fluorine-containing compounds combined with other matrix materials. This composite structure provides both the light-blocking function and the hydrophobic surface properties needed to prevent ink bleed.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If fluorine-containing compounds are added to black matrix composition, then ink bleed is prevented through hydrophobicity, but the composition complexity increases

Engineering Contradiction:

Improveink bleed preventionVSAvoidcomposition complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Specific fluorine-containing compounds are selected and optimized at controlled concentrations (0.1-5 wt%) to achieve the desired hydrophobicity. By optimizing this parameter, the solution prevents ink bleed while minimizing composition complexity.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If more ink is injected to compensate for volatility, then sufficient ink fills pixel area, but ink overflows to black matrix surface causing bleed between adjacent pixels

Engineering Contradiction:

Improveink volumeVSAvoidink bleed

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The hydrophobic surface created by fluorine-containing compounds converts the potentially harmful effect of excess ink into a beneficial outcome. The excess ink that would normally cause bleed is now repelled by the hydrophobic surface, preventing contamination between adjacent pixel areas.

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

The hydrophobic black matrix effectively increases the contact angle of hydrophilic ink, preventing ink bleed and enhancing the color properties and display quality of liquid crystal display devices.

Implementation Method 1

the binder resin includes an acryl-based copolymer containing fluorine and has a hydroxyl group combined with a side chain of the acryl-based copolymer

Methodology Applied

Scientific EffectHydrophobicity: Hydrophobe

Implementation Method 2

forms a thermally cross-linked resin with fluorine exposure

Methodology Applied

Scientific EffectThermal cross-linking:

Implementation Method 3

about 0.1 to about 1.0 part by weight of photoinitiator, about 5 to about 20 parts by weight of photo-polymerizable monomer

Methodology Applied

Scientific EffectPhoto-polymerization: Photopolymerisation

Data Source

PatentUS7604921B2Black matrix composition, black matrix prepared using the same, method of forming a black matrix pattern using the same and method of manufacturing a color filter substrate using the same

Publication Date: 2009.10.20 LONESTAR CRYSTAL DISPLAY LLC

AI summary

A black matrix composition includes about 40 parts by weight of a pigment dispersion, about 0.1 to about 1.0 part by weight of a photoinitiator, about 5 to about 20 parts by weight of a photo-polymerizable monomer, about 5 to about 20 parts by weight of a binder resin including an acryl-based copolymer containing fluorine and having a hydroxyl group combined with a side chain of the acryl-based copolymer, about 0.1 to about 0.5 part by weight of epoxy-based monomer containing fluorine and about 35 to about 55 parts by weight of a solvent. A black matrix pattern formed of the black matrix minimizes an ink bleed, thereby improving color property of a liquid crystal display device to which the black matrix pattern is applied.