Liquid Crystal Display Post Spacer Height Control via Color Filter Overlap
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in controlling the height of post spacers using color filter layers, which requires multiple processes and materials, and increases manufacturing costs due to fixed spacer heights and the need for additional photomasks.
Innovation Solution
A liquid crystal display device design where the post spacer height is controlled by overlapping color films forming the color filter layers, with the fourth color film acting as a spacer, allowing for adjustable thickness and reduced process complexity by eliminating the need for a dedicated spacer material and process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated photopolymer process is used to construct post spacers, then the space between substrates can be maintained constant, but the number of manufacturing processes and kinds of material increase
Solution Approach 1:
The patent merges the post spacer function with the color filter layers by forming the spacer from the same photopolymer material used for color filters. This integration eliminates the need for separate dedicated spacer materials and processes, reducing manufacturing complexity while maintaining the constant space function between substrates
Solution Approach 2:
The photopolymer material serves multiple functions: it acts as both the color filter layer and the post spacer. By making the color filter layers extend into the black matrix region and form protrusions, the same material performs both optical filtering and mechanical spacing functions, reducing the number of material types needed
2Ease of manufacture
If the height of post spacer is fixed by the thickness of color films, then manufacturing is simplified, but the space between substrates cannot be optionally set
Solution Approach 1:
The patent applies local quality by creating regions with different film thicknesses within the same color filter layer structure. The color filter layers have varying thicknesses in different regions (thinner in pixel areas, thicker in black matrix regions), allowing the post spacer height to be locally adjusted to define the desired space between substrates while maintaining standard manufacturing processes
Solution Approach 2:
The invention introduces dynamic adjustability by controlling the thickness of color filter layers in the black matrix region to vary the post spacer height. This allows the space between substrates to be optionally set by adjusting film thickness parameters during manufacturing, providing versatility without requiring dedicated spacer processes
3Manufacturing precision
If the thickness of red color film is made different between pixel and post spacer portions, then post spacer height can be controlled, but the number of processes increases and additional photomask is required
Solution Approach 1:
The patent segments the color filter layer formation into distinct functional regions: pixel portions and black matrix portions. By controlling the thickness of color filter layers differently in these regions (thinner in pixel areas, thicker in black matrix areas), the post spacer height is precisely controlled without requiring separate manufacturing processes or additional photomasks
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
Enables the control of post spacer height with a minimal number of processes and low costs, reducing material usage and manufacturing complexity while maintaining operational characteristics of liquid crystal molecules.
Implementation Method 1
by applying a voltage to electrodes (called pixel electrodes) formed on one of such substrates in a reticular pattern, and generating an electric force line between the pixel electrodes and an electrode (called a common electrode) formed on the same substrate or the other substrate, changes a liquid crystal molecular orientation direction, and controls a light transmittance
Implementation Method 2
it has been the practice to use a photopolymer to construct on a substrate a columnar structural object called a post spacer, a photo spacer, or a columnar spacer
Data Source
AI summary
A liquid crystal display device according to the invention includes a first substrate, on a surface of which are formed: a first color film which has a color other than black, and one portion of which configures a first pixel; a second color film, one portion of which configures a second pixel adjacent to the first pixel; a third color film, at least one portion of which configures a third pixel; and a fourth color film, a second substrate, and a liquid crystal layer sandwiched between the first substrate and second substrate, wherein the first color film and second color film have a first overlapping portion in which they overlap each other in the boundary between the first pixel and second pixel, and the fourth color film, being formed on the first overlapping portion, configures a post spacer which defines the space between the first substrate and second substrate.