Alignment Film Frame for LCD Edge Rectilinearity
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Solution Overview
Problem
Existing methods for forming alignment films in liquid crystal display devices face challenges in achieving both edge rectilinearity and uniformity, particularly in small-size panels where the bezel region is insufficient, leading to issues with adhesion strength and moisture ingress, which affect display quality.
Innovation Solution
The use of a highly water-repellent organic material with low solubility in the application liquid to form a frame around the alignment film, which regulates the peripheral edge and prevents spreading, combined with an ink jet method for precise application, ensures both edge rectilinearity and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ink viscosity is lowered to improve flow on uneven substrates, then application unevenness is reduced, but edge rectilinearity deteriorates
Solution Approach 1:
A frame structure is formed on the substrate before applying the alignment film. This frame acts as a physical boundary that confines the ink application liquid within a specific region, preventing it from spreading beyond the desired edges. The frame is created through ink jet application of a material that forms a raised structure, which is then used to define the boundaries of the alignment film formation area.
Solution Approach 2:
The frame structure serves as an intermediary element between the ink jet application system and the alignment film. It mediates the interaction by providing a physical barrier that controls ink spread, allowing the use of lower viscosity ink (which flows better on uneven surfaces) while maintaining sharp edges through the frame's confining effect rather than relying on high viscosity alone.
2Length of moving object
If bezel width is reduced to achieve thinner display devices, then device thickness is reduced, but alignment film adhesion and moisture sealing deteriorate
Solution Approach 1:
The solution moves from a two-dimensional planar sealing approach to a three-dimensional approach by forming a raised frame structure. This frame creates a physical barrier that extends vertically from the substrate surface, providing both mechanical support for adhesion and a barrier against moisture ingress, thereby maintaining reliability even when the horizontal bezel width is reduced.
Solution Approach 2:
The frame structure is formed in advance before the alignment film and seal member are applied. This preliminary structure provides a ready-made framework that enhances adhesion and moisture sealing capabilities, allowing the device to achieve narrow bezels without compromising reliability, as the frame compensates for the reduced margin area.
3Ease of manufacture
If ink jet application is used to improve placement accuracy, then manufacturing flexibility is improved, but edge rectilinearity and uniformity deteriorate due to ink spreading
Solution Approach 1:
The frame is formed through ink jet application before the alignment film is applied. This frame structure creates physical boundaries that confine the subsequent alignment film ink, preventing it from spreading beyond the desired rectangular region. The frame's raised structure acts as a barrier that maintains sharp edges even though the alignment film is applied using ink jet method which inherently causes some spreading.
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 enables the formation of alignment films with improved edge rectilinearity and reduced unevenness, enhancing display quality and yield, even in narrow bezel designs, while preventing moisture ingress and ensuring high image quality.
Implementation Method 1
a frame is arranged inside the seal member around the first alignment film to surround the first alignment film
Implementation Method 2
a material forming the frame is a highly water repellent organic material having a low solubility in an application liquid
Implementation Method 3
an application liquid is ejected onto an alignment film formation region of the glass substrate by an ink jet method
Data Source
AI summary
A technique for attaining both improvement of edge rectilinearity of an alignment film and reduction of unevenness is provided. A liquid crystal display device includes a first substrate on which a first alignment film is formed, a second substrate on which a second alignment film is formed, and a liquid crystal layer sandwiched between the first and second substrates. A material forming a frame arranged to surround the first alignment film inside a seal member with which the first and second substrates are bonded to each other is a highly water repellent organic material having a low solubility in an application liquid for forming the first alignment film.