Laser Delamination of Large Area Liquid Crystal Device Patterns

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Solution Overview

Problem

Current methods for forming patterns in large area liquid crystal devices are inefficient, requiring complex processes like photolithography and etching, which increase costs and reduce productivity due to issues with adhesiveness and durability, especially when removing the liquid crystal alignment film and conductive layer.

Innovation Solution

A method using a Q-switching IR laser with a beam diameter of 1 mm to 16 mm and energy per pulse of 0.05 J to 2.5 J to delaminate the conductive layer and liquid crystal alignment film, improving processing speed and minimizing substrate damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photolithography, inkjet, or slot die methods are used to remove the liquid crystal alignment film and conductive layer, then pattern formation is achieved, but overlay precision requirements increase facility cost and complexity

Engineering Contradiction:
Improveoverlay precisionVSAvoidfacility complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical/chemical patterning methods (photolithography, inkjet, slot die) with a laser-based method. The laser beam directly ablates or modifies the liquid crystal alignment film and conductive layer to form patterns, eliminating the need for complex photolithography equipment, alignment systems, and chemical processing facilities. This substitution dramatically reduces facility complexity while maintaining or improving manufacturing precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If laser beam with diameter of several tens of micrometers is used for etching, then the conductive layer and liquid crystal alignment film are removed, but production speed decreases and residues increase

Engineering Contradiction:
Improveremoval qualityVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the laser beam diameter parameter from several tens of micrometers to several hundred micrometers (e.g., 300-500 μm). This parameter change allows the laser to process larger areas simultaneously, dramatically increasing production speed. The patent also optimizes other laser parameters such as pulse duration, energy density, and scanning speed to ensure clean removal without residues despite the larger beam size.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If conventional etching methods are used, then the liquid crystal alignment film is removed, but the removed cross-section is not smooth and residues are increased

Engineering Contradiction:
Improvecross-section smoothnessVSAvoidresidues
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent employs periodic pulsed laser irradiation to remove the liquid crystal alignment film and conductive layer. The pulsed action allows controlled heating and ablation, creating smooth cross-sections without mechanical contact that would cause roughness. By optimizing pulse duration and frequency, the laser selectively removes materials cleanly, minimizing residues while maintaining excellent cross-section smoothness.

Inventive Principle:
Principle #19Periodic action

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 approach enhances the speed and quality of the delamination process while maintaining economic efficiency and reducing substrate damage, thus improving the overall productivity of pattern formation in large area liquid crystal devices.

Implementation Method 1

exposing one area of the substrate by delaminating one area of the conductive layer and the liquid crystal alignment film by irradiating a laser to the large area liquid crystal device

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

delaminating one area of the conductive layer and the liquid crystal alignment film by irradiating a laser

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3539773B1Method of forming petterns for a large area liquid crystal device
Publication Date: 2020.09.16 LG CHEM LTD
  • EP3539773B1 patent drawingFigure 1~2
  • EP3539773B1 patent drawingFigure 3~4
  • EP3539773B1 patent drawingFigure 5~6(b)

AI summary

The present invention relates to a pattern forming method of a large area liquid crystal device.