Liquid Crystal Display Alignment Film Through-Hole Filling
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Solution Overview
Problem
High-resolution liquid crystal display devices face display unevenness due to regions where the alignment film is not formed, particularly as the pixel size decreases and the distance between through-holes narrows, leading to light leakage and visible display issues.
Innovation Solution
A liquid crystal display device structure is implemented with a connection conductive layer formed on the inner wall and surrounding area of through-holes, featuring a step covered with an alignment film, using indium tin oxide (ITO) or a metal layer with a thickness of 100 nm or more, and projecting and recessed portions around the through-holes to facilitate alignment film entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is reduced to enhance resolution, then the screen resolution is improved, but the alignment film is less likely to be formed in through-holes causing display unevenness
Solution Approach 1:
The patent applies a preliminary action by forming projecting portions on the insulating film surface around through-holes before applying the alignment film. These projecting portions create a meniscus effect that guides the liquid alignment film material into the through-holes during the application process, ensuring proper alignment film formation even in high-resolution displays with small pixel sizes
Solution Approach 2:
The patent implements local quality by creating localized projecting portions only in the through-hole surrounding areas of the insulating film, while maintaining the normal flat structure in other pixel regions. This localized modification enables the alignment film to enter through-holes without affecting the overall pixel structure or requiring changes to the entire manufacturing process
2Manufacturing precision
If the through-hole diameter is reduced to prevent alignment film formation issues, then alignment film formation is improved, but the connection between pixel electrode and TFT source electrode becomes more difficult
Solution Approach 1:
The patent solves the contradiction by transitioning from a two-dimensional planar structure to a three-dimensional structure with projecting portions. These projecting portions create a stepped profile that facilitates liquid material entry into through-holes through capillary action and meniscus formation, enabling proper alignment film formation without requiring smaller through-hole diameters
3Ease of manufacture
If projecting and recessed portions are formed around through-holes to facilitate material entry, then material entry is improved, but the device structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the insulating film structure into distinct regions: flat areas for normal pixel operation and localized projecting portions around through-holes. This segmentation allows the alignment film application process to be optimized for through-hole filling without complicating the overall device structure or requiring additional manufacturing steps beyond standard photolithography and etching processes
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 structure effectively prevents display unevenness by ensuring the alignment film is formed in through-holes, reducing light leakage and maintaining image quality even at smaller pixel sizes without excessively increasing process complexity.
Implementation Method 1
a step is formed at an edge portion of the connection conductive layer in the through-hole surrounding area of the insulating film, the step being covered with an alignment film
Data Source
AI summary
The invention prevents the display unevenness of a high-resolution liquid crystal display device that results from the presence of regions where an alignment film is not applied. The invention provides a liquid crystal display device including: a TFT substrate having scan lines, video signal lines, and pixels formed by the intersecting scan lines and video signal lines; a counter substrate; and a liquid crystal layer placed between the TFT substrate and the counter substrate. Each of the pixels includes a TFT, a pixel electrode, a common electrode, and a through-hole and an opening that are used to connect the TFT and the pixel electrode. Connective ITO is formed in and around the through-hole at the same time as the common electrode is formed. A step d is formed at an edge portion of the connective ITO and covered with an alignment film.