LCD Liquid Crystal Extraction via Selective Solvent Contact

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Solution Overview

Problem

Current methods for recycling liquid crystals from LCD screens are complex, contaminated with broken glass and metal particles, and not easily scalable due to the mixture's complexity and pollution issues, making it difficult to extract and recycle the liquid crystals effectively.

Innovation Solution

A method involving partial contact of the functional face of the LCD supports with a solvent, such as acetone or isopropanol, without immersing the entire support, using ultrasound to dissolve the liquid crystals while preventing contamination, and subsequent distillation and chromatography to separate and purify the liquid crystals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the support is immersed in alcohol baths subjected to ultrasound to dissolve liquid crystals, then the liquid crystals can be extracted, but the extracted mixture becomes excessively complex and contaminated with broken glass, metal particles, and dissolved cover films

Engineering Contradiction:
Improveliquid crystals extractionVSAvoidcontamination
Core Design Contradiction:
Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent extracts only the necessary part (liquid crystals) by using a solvent that selectively dissolves liquid crystals without dissolving other components like glass, metal particles, or cover films. The functional face is contacted with the solvent in a controlled manner to extract liquid crystals while leaving contaminants behind.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different properties to different parts of the system: the solvent is specifically chosen to have selective dissolving capability for liquid crystals only, and the functional face is treated locally with the solvent rather than immersing the entire support, creating a localized extraction zone that avoids contamination.

Inventive Principle:
Principle #3Local quality

2Productivity

If the functional face is brought into contact with solvent solution to dissolve liquid crystals, then the extraction efficiency improves, but the solution level must be controlled to avoid contact with the opposite face

Engineering Contradiction:
Improveextraction efficiencyVSAvoidsolution level control
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent uses partial action by contacting only the functional face with the solvent solution rather than immersing the entire support. The solution level is controlled to be just enough to wet the functional face and dissolve liquid crystals, avoiding excessive action that would cause the solution to contact the opposite face and create contamination risks.

Inventive Principle:
Principle #16Partial or excessive action

3Speed

If ultrasound is used to dissolve liquid crystals in alcohol baths, then the dissolution process is accelerated, but the complexity and pollution of the extracted mixture increases

Engineering Contradiction:
Improvedissolution speedVSAvoidmixture complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent extracts only the liquid crystals using a selectively designed solvent system that does not dissolve other materials. By taking out only the desired component through selective dissolution rather than complete immersion, the mixture remains simple and manageable while still achieving fast dissolution through ultrasound.

Inventive Principle:
Principle #2Taking out (Extraction)

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 method allows for efficient and clean extraction of liquid crystals, reducing contamination and complexity, facilitating industrial-scale recycling with high yield and ease of implementation, and maintaining the quality of the recovered materials.

Implementation Method 1

a solution containing at least one solvent capable of dissolving said liquid crystals present on said functional face

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

ultrasound is generated in said solution so as to cause the phenomenon of cavitation, in particular at the level of said functional face

Methodology Applied
Scientific EffectAcoustic cavitation: Acoustic Cavitation

Data Source

PatentEP3111276B1Device and method for extracting the liquid crystals contained in an element that comprises a first and a second support
Publication Date: 2019.10.16 CENT NAT DE LA RECH SCI (C N R S)
  • EP3111276B1 patent drawingFigure 1~2
  • EP3111276B1 patent drawingFigure 3
  • EP3111276B1 patent drawingFigure 4

AI summary

The invention relates to a device and a method for extracting the liquid crystals contained in a screen that comprises a first support (P) and a second support (P), each of which has a functional surface (PI). The functional surfaces (PI) are mounted across from each other in such a way as to create a space containing the liquid crystals. In said method, the first and second supports are separated from one another, the functional surfaces thus being at least partially covered by a film of liquid crystals. According to the invention, the functional surface (PI) of the first support (P) and/or the second support (P) is brought in contact with a solution (S) containing at least one solvent that can dissolve the liquid crystals on the functional surface in such a way that said solution is not in contact with the surface opposite the functional surface.