Polymer Adhesive Layer for LCD Gate Line Peeling Prevention
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Solution Overview
Problem
Liquid crystal display devices face issues such as peeling of metal gate lines from substrates, uneven distribution and movement of spacers due to increased cell gap, and the need for additional photo-etching processes to prevent overcoat layer peeling, leading to increased costs and process time.
Innovation Solution
A polymer adhesive layer is interposed between substrates and patterns, or between patterns, to enhance adhesive characteristics, formed using methods like spin coating or ink-jet printing, eliminating the need for photo-etching and stabilizing the orientation of liquid crystals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal gate line is formed directly on a substrate, then the manufacturing process is simple, but the gate line peels off from the substrate
Solution Approach 1:
An organic adhesive layer is introduced as an intermediary between the metal gate line and the substrate. This adhesive layer serves as a mediator that provides both chemical bonding to the substrate and metallurgical bonding to the gate line, resolving the adhesion problem while maintaining process simplicity
Solution Approach 2:
The gate line structure is made composite by stacking multiple layers: substrate, organic adhesive layer, metal layer, and inorganic adhesive layer. This composite structure combines the advantages of different materials to achieve both ease of manufacture and reliable adhesion
2Length of stationary object
If the cell gap between substrates is increased, then the liquid crystal display performance is improved, but the spacers become unevenly distributed and movable
Solution Approach 1:
The organic adhesive layer is formed in advance at the spacer positions before the metal gate line and spacer formation processes. This preliminary action creates predetermined adhesion zones that guide spacer placement and prevent movement, ensuring uniform distribution even with increased cell gap
Solution Approach 2:
The organic adhesive layer is selectively formed only at specific locations where spacers will be placed, rather than uniformly across the entire substrate. This local quality approach provides targeted adhesion where needed while maintaining overall spacer uniformity and stability
3Manufacturing precision
If an overcoat layer is formed on the substrate including color filter layers, then the height difference is compensated, but the overcoat layer peels off at the edges
Solution Approach 1:
The organic adhesive layer serves as an intermediary between the substrate and the overcoat layer at the edge regions. This mediator prevents direct contact between the overcoat layer and substrate at edges, eliminating the peeling problem while maintaining the overcoat layer's height compensation function
4Reliability
If additional photo-etching processes are performed to prevent peeling, then the adhesion reliability is improved, but the manufacturing cost and process time increase
Solution Approach 1:
The mechanical photo-etching process is replaced with a chemical/physical coating process. The organic adhesive layer is formed by coating methods such as spin coating, dip coating, or spray coating, which are simpler and faster than photo-etching, thereby improving productivity while maintaining adhesion reliability
Solution Approach 2:
The approach to preventing peeling is changed from a post-formation treatment (photo-etching) to a pre-formation preparation (adhesive layer coating). This parameter change in the process sequence eliminates the need for additional photo-etching steps, reducing both cost and time
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 polymer adhesive layer improves reliability by preventing peeling, stabilizing spacer positions, and simplifying the manufacturing process, reducing errors and costs while enhancing liquid crystal orientation and adhesive properties.
Implementation Method 1
a polymer adhesive layer interposed between a substrate and a pattern and/or between one pattern and another pattern
Implementation Method 2
formed using methods like spin coating or ink-jet printing
Data Source
AI summary
A liquid crystal display device having a polymer adhesive layer interposed between a substrate and a pattern or between one pattern and another pattern, and a method for manufacturing the same are disclosed. The polymer adhesive layer is interposed where peeling problems occur. The polymer adhesive layer reduces process errors and improves reliability. The device includes: a first substrate; gate lines, data lines, TFTs, and pixel electrodes on a surface of the first substrate; a second substrate bonded to the first substrate; a liquid crystal layer between the first and second substrates; a black matrix layer and a color filter layer on a surface of the second substrate; a sealant formed along an edge of a substrate that bonds the first and second substrates to each other; spacers that maintain a cell gap between the first and second substrates; and a polymer adhesive layer that improves adhesive characteristics.