Ultrasonic Bubble Removal in Polyimide Filtration

Solution Overview

Problem

Existing polyimide solutions in flexible active matrix organic light emitting diode (AMOLED) production contain micron-sized bubbles and gels, leading to defects and instability in subsequent coating processes, with current vacuum-based methods being time-consuming and affecting industrial mass production.

Innovation Solution

A filtering device and method involving stepwise bubble and gel filtration systems with progressively finer filter fineness, including a reaction kettle, stirring member, and gel filtering system with aluminum oxide filter bodies, to effectively remove bubbles and gels from the polyimide solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vacuuming is performed for a long time (36 to 72 hours) to remove bubbles, then bubble removal is improved, but production time increases and organic solvents volatilize

Engineering Contradiction:

Improvebubble removal effectivenessVSAvoidproduction time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical vacuum system with an ultrasonic wave system to remove bubbles. The ultrasonic wave generation unit generates ultrasonic waves that propagate through the polyimide solution, causing bubbles to collapse through cavitation effects, eliminating the need for prolonged vacuuming while maintaining effective bubble removal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameter approach from using vacuum pressure to using ultrasonic wave frequency and intensity. By controlling ultrasonic parameters (frequency, power, duration), the system achieves rapid bubble removal without the time-consuming and solvent-volatilizing vacuum process.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If vacuuming is performed for a long time to remove bubbles, then bubble removal is improved, but organic solvents volatilize and solution composition deviates

Engineering Contradiction:

Improvebubble removal effectivenessVSAvoidorganic solvent retention

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces the mechanical vacuum system with an ultrasonic wave system to remove bubbles. The ultrasonic wave generation unit generates ultrasonic waves that propagate through the polyimide solution, causing bubbles to collapse through cavitation effects, eliminating the need for prolonged vacuuming while maintaining effective bubble removal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameter approach from using vacuum pressure to using ultrasonic wave frequency and intensity. By controlling ultrasonic parameters (frequency, power, duration), the system achieves rapid bubble removal without the time-consuming and solvent-volatilizing vacuum process.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple filtration stages are implemented to improve bubble and gel removal, then filtering effectiveness is improved, but device complexity increases

Engineering Contradiction:

Improvefiltering effectivenessVSAvoidfiltration system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple filtration functions into a single integrated filtration device. The device includes a first filtration unit with a first filter membrane and a second filtration unit with a second filter membrane, both integrated into one system that processes the polyimide solution in sequence, achieving effective bubble and gel removal without requiring separate complex systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the filtration process into two distinct stages with different filter membrane pore sizes. The first filtration unit handles larger particles and bubbles, while the second filtration unit handles smaller particles, creating a hierarchical filtration system that improves effectiveness while maintaining manageable complexity.

Inventive Principle:

Principle #1Segmentation

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

Improves the removal efficiency of bubbles and gels, enhancing product yield in subsequent coating processes by utilizing a multi-stage filtration approach that addresses the limitations of existing methods.

Implementation Method 1

an ultrasonic wave generation unit configured for generating ultrasonic waves to be incident on the polyimide solution in the reaction kettle, so as to cause bubbles in the polyimide solution to collapse

Methodology Applied

Scientific EffectUltrasonic cavitation: Cavitation

Implementation Method 2

a filtration unit configured for filtering and removing particles in the polyimide solution; a filter membrane wound on the filtration unit in a layered manner

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentUS11471792B2Filtering device and filtering method

Publication Date: 2022.10.18 WUHAN CHINA STAR OPTOELECTRONICS SEMICONDUCTOR DISPLAY TECHNOLOGY CO LTD

AI summary

A filtering device and a filtering method are provided. The filtering device includes a bubble filtering system. The bubble filtering system at least includes a first bubble filtering system and a second bubble filtering system. The first bubble filtering system configured for performing a first bubble filtration in the solution. The second bubble filtering system configured for performing a second bubble filtration in the solution. Filter fineness of the second bubble filtering system is higher than filter fineness of the first bubble filtering system.