UV Curable Pre-polymer Monomer Blend for LCD Overcoat Shrinkage
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Solution Overview
Problem
UV curable liquid pre-polymers used in non-exposure processes for LCD manufacturing shrink or contract during heat treatment, affecting the uniformity and stability of the overcoat and white color filter layers, leading to defects in the device.
Innovation Solution
Incorporating a mixture of mono-functional, di-functional, and tri-functional monomers in the UV curable liquid pre-polymer, along with photo-initiators, to form a cross-linking structure that maintains volume stability during curing and heat treatment, thereby minimizing shrinkage and enhancing thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UV curable liquid pre-polymer is used as pattern material in non-exposure process, then manufacturing efficiency is improved, but thermal stability deteriorates causing shrinkage during heat treatment
Solution Approach 1:
The patent uses a composite monomer system combining mono-functional, di-functional, and tri-functional monomers. This composite approach creates a balanced polymer network that achieves both ease of curing (maintaining productivity) and thermal stability (preventing shrinkage). The multi-functional monomers work synergistically to form a cross-linked structure with improved dimensional stability during heat treatment.
Solution Approach 2:
The patent modifies the chemical composition parameters of the UV curable liquid pre-polymer by incorporating specific ratios of mono-functional, di-functional, and tri-functional monomers. This parameter change transforms the material properties to achieve both rapid curing (maintaining manufacturing efficiency) and resistance to thermal shrinkage (improving thermal stability).
2Reliability
If UV curable liquid pre-polymer is heat-treated, then curing process is completed, but shrinkage or contraction occurs affecting layer uniformity
Solution Approach 1:
The patent incorporates di-functional and tri-functional monomers that create a cross-linked network structure before heat treatment. This pre-formed network acts as a cushioning framework that prevents excessive shrinkage during subsequent heat treatment, thereby maintaining layer uniformity while ensuring complete curing. The cross-linked structure provides dimensional stability during the thermal processing stage.
3Device complexity
If overcoat layer and column spacer are formed as one body, then manufacturing steps are reduced, but shrinkage during baking affects device quality
Solution Approach 1:
The patent combines the overcoat layer and column spacer into a single integrated structure formed from the UV curable liquid pre-polymer. This merging reduces the number of manufacturing steps while the multi-functional monomer system ensures that the combined structure maintains dimensional stability during heat treatment, preventing quality issues that would normally arise from such integration.
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 use of this monomer blend prevents significant contraction of the pattern layers, ensuring uniform thickness and stability of the overcoat and white color filter layers, even after heat treatment, thus improving the quality and reliability of the LCD device.
Implementation Method 1
UV curable liquid pre-polymer, and liquid crystal display device using the same and manufacturing method thereof
Data Source
AI summary
A liquid-crystal display includes a first substrate and a second substrate disposed opposite the first substrate, and a plurality of pixel areas formed on the first substrate, where each pixel area has red, green, blue, and white sub-pixel areas. Red, green and blue color filter layers are disposed on the red, green and blue sub-pixel areas, respectively, and an overcoat layer is disposed over the red, green and blue color filter layers, where a portion of the overcoat layer forms a white color filter layer in the white sub-pixel area. The overcoat layer is formed from a UV-curable liquid pre-polymer material, which includes monomers each having a mono-functional group, and at least a di-functional group or a tri-functional group.