Infrared Transmittance Ink Composition for Narrow Bezel Inspection

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Solution Overview

Problem

Existing ink compositions for display devices require post-process heat treatment to adhere to substrates and cannot be inspected for alignment and pressure marks without destruction, limiting their application in narrow bezel designs for extended screens.

Innovation Solution

Development of an infrared transmitting inkjet ink composition comprising lactam black pigment, dispersant, epoxy compound, vinyl ether compound, oxetane compound, photopolymerization initiator, and organic solvent, allowing non-destructive inspection using an infrared camera and improved adhesion and inkjet process performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If carbon black ink is used for bezel pattern printing, then the ink provides good black color and coverage, but alignment marks cannot be checked with infrared camera and pressure marks cannot be detected non-destructively

Engineering Contradiction:

Improveinfrared transmittanceVSAvoidinfrared blocking

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by replacing carbon black with lactam black pigment, which has different infrared absorption characteristics. This parameter change allows the ink to transmit infrared rays while maintaining black color, enabling non-destructive inspection with infrared cameras

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining lactam black pigment with specific resins (epoxy compound, vinyl ether compound, oxetane compound) and photopolymerization initiators. This composite material achieves both the desired optical properties for infrared transmittance and the required mechanical properties for adhesion and curing

Inventive Principle:

Principle #40Composite materials

2Strength

If conventional ink composition is used, then the ink can be adhered to substrate only after heat treatment post-process, but this increases manufacturing complexity and time

Engineering Contradiction:

Improveadhesion to substrateVSAvoidheat treatment process

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent replaces the thermal field (heat treatment) with a photonic field (UV irradiation) to achieve adhesion. The photopolymerization initiator in the ink formulation enables curing and adhesion through light exposure instead of heat treatment, simplifying the manufacturing process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the chemical composition of the ink by incorporating photopolymerization initiators and specific resin systems that cure under UV light. This parameter change in the ink formulation enables adhesion through photopolymerization rather than thermal processes

Inventive Principle:

Principle #35Parameter changes

3Shape

If black ink is printed on display substrate, then the bezel pattern provides good visual contrast, but alignment marks must be removed for post-process and testing requires sample destruction

Engineering Contradiction:

Improvebezel pattern visibilityVSAvoidalignment mark information

Core Design Contradiction:

ShapeVSLoss of information

Solution Approach 1:

The patent changes the optical parameters of the ink by selecting lactam black pigment with specific infrared transmission properties. This allows the ink to appear black in visible light (maintaining bezel visibility) while transmitting infrared rays (enabling alignment mark detection through the printed pattern)

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

Enables non-destructive inspection of alignment and pressure marks post-ACF bonding, enhances substrate adhesion, and maintains inkjet process performance without heat treatment, supporting narrow bezel designs for extended screens.

Implementation Method 1

a photopolymerization initiator

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

Infrared transmitting ink composition for inkjet... enables to check alignment marks using an infrared camera

Methodology Applied

Scientific EffectInfrared transmission: Infrared Radiation

Data Source

PatentUS11760891B2Infrared ray transmittance ink composition for inkjet, method for preparing a bezel pattern using the same, the bezel pattern using the same method and display panel comprising the bezel pattern

Publication Date: 2023.09.19 LG CHEM LTD

AI summary

An infrared transmitting ink composition for inkjet, a method of forming a bezel pattern using the same, a bezel pattern manufactured thereby, and a display substrate comprising the same are disclosed. The ink composition may check alignment marks using an infrared camera and detect pressure marks by non-destructive inspection even after the bezel pattern thereof is printed on a display substrate, and also may improve the adhesion to the substrate and the performance of inkjet process. The infrared ray transmitting ink composition for ink jet comprises a lactam black pigment, a dispersant, an epoxy compound, a vinyl ether compound, an oxetane compound, a photopolymerization initiator and an organic solvent.