Ball Spacer Placement in Liquid Crystal Display Black Matrices
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Solution Overview
Problem
Liquid crystal display devices using ball spacers are prone to gravity and touch defects due to spacer movement, leading to light leakage and reduced contrast ratios, while column spacers address diffusion issues but introduce gravity defects and touch sensitivity.
Innovation Solution
A color filter substrate with black matrices and ball spacers, where the thickness of the color filter overlapping regions is greater than the spacer disposed regions, and the spacers are made of resilient plastic to maintain cell gap and resist displacement during impacts and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ball spacers are used to maintain cell gap, then the thermal expansion coefficient matches liquid crystal material for any temperature conditions, but the spacers shift during vibration or impact causing light leakage and reduced contrast ratio
Solution Approach 1:
The black matrix is formed with a protrusion that extends upward to a height greater than the ball spacer diameter, creating a pre-formed recess structure before the ball spacer is placed. This preliminary structural preparation ensures the ball spacer is confined and cannot shift during vibration or impact, while still maintaining the cell gap function.
Solution Approach 2:
The black matrix protrusion acts as an intermediary structure between the substrate and the ball spacer. It provides a mechanical constraint environment for the ball spacer, preventing displacement while allowing the ball spacer to maintain the cell gap. The recess formed by the protrusion serves as the mediating structure that resolves the contradiction between mobility and stability.
2Manufacturing precision
If column spacers are used to suppress diffusion and light leakage, then manufacturing precision improves, but gravity defects and touch defects occur
Solution Approach 1:
The black matrix is designed with different local structures: a protrusion region that extends upward to constrain the ball spacer, and a recess region that provides space for the ball spacer to reside. This local differentiation allows the same black matrix structure to provide both precise spacer positioning and resistance against gravity and touch defects.
Solution Approach 2:
The invention changes the geometric parameters of the black matrix, specifically creating a protrusion with height greater than the ball spacer diameter. This parameter change transforms the black matrix from a flat structure to a three-dimensional constrained structure, enabling it to prevent ball spacer displacement while maintaining manufacturing precision.
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 solution effectively suppresses gravity, touch, and light leakage defects, improving the accuracy of spacer placement and maintaining a consistent cell gap, thereby enhancing the contrast ratio of liquid crystal display devices.
Implementation Method 1
the spacers are made of resilient plastic to maintain cell gap and resist displacement during impacts and vibrations
Data Source
AI summary
A color filter substrate for a liquid crystal display device and a method of fabricating the same includes black matrixes on a transparent insulating substrate, the black matrixes defining pixel areas and having a first region and a second region, color filters in the pixel areas and having areas overlapping the first region of the black matrixes, and ball spacers above the second region of the black matrixes, wherein a thickness of the first region is greater than a thickness of the second region.