Array Substrate Color Filter for High-Definition LCDs

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Solution Overview

Problem

High-definition liquid crystal display devices face color mixture issues due to alignment deviations between the array and opposite substrates, particularly at resolutions above 500 ppi, where the conventional method of forming a color filter on the opposite substrate is insufficient in preventing color mixture, especially when viewed obliquely.

Innovation Solution

The solution involves forming a color filter on the array substrate, with specific configurations such as an overcoat film thickness between 50% to 150% of the color filter thickness, and ensuring the distance from the video signal line to the liquid crystal layer is within certain ratios relative to the pixel size, along with a black matrix that acts as a light shielding film, to minimize alignment deviations and color mixture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a color filter is formed on the opposite substrate, then the manufacturing process is simplified, but alignment deviation between substrates causes color mixture at high resolutions

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidalignment accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional structure by forming the color filter on the array substrate instead of the opposite substrate. This inversion allows the color filter to be positioned closer to the liquid crystal layer, reducing the impact of alignment deviation between substrates and eliminating color mixture at high resolutions.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent addresses the alignment deviation problem by changing the spatial dimension where the color filter is formed. Instead of forming it on the opposite substrate at a distance from the liquid crystal layer, the color filter is formed on the array substrate in close proximity to the liquid crystal layer, effectively reducing the dimensional gap that causes alignment errors.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the pixel size is reduced to increase display density, then the display resolution is improved, but color mixture becomes more prominent

Engineering Contradiction:

Improvedisplay resolutionVSAvoidcolor mixture

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by forming the color filter in close proximity to the liquid crystal layer within each pixel region. This localized positioning ensures that even when pixel size is reduced, the color filter remains precisely aligned with its corresponding pixel area, preventing color mixture from adjacent pixels.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the distance from the color filter to the liquid crystal layer is increased, then the manufacturing tolerance is relaxed, but color mixture increases due to alignment deviation

Engineering Contradiction:

Improvemanufacturing toleranceVSAvoidcolor mixture

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional arrangement by positioning the color filter on the array substrate side rather than the opposite substrate side. This inversion places the color filter in close proximity to the liquid crystal layer, minimizing the distance and thereby reducing the impact of alignment deviation, while still allowing for practical manufacturing tolerances.

Inventive Principle:

Principle #13The other way round (Inversion)

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 configuration effectively reduces color mixture in high-definition screens by controlling alignment accuracy and optimizing the thickness and positioning of layers, thereby improving color purity and reducing color change amounts to acceptable levels even at high resolutions.

Implementation Method 1

the video signal line is a light shielding film

Methodology Applied

Scientific EffectLight shielding: Absorption (EM radiation)

Data Source

PatentUS10073313B2Display device and manufacturing method thereof

Publication Date: 2018.09.11 MAGNOLIA WHITE CORP

AI summary

A provided is a liquid crystal display device with a high definition screen and less color mixture. On an array substrate, a pixel is formed between the adjacent video signal lines, a color filter is formed within the pixel, a flattening film is formed on the color filter, a lower layer is formed on the flattening film, and an upper layer having a slit is formed on the lower layer with an interlayer insulating film interposed therebetween; and on the array substrate, an opposite substrate is arranged with a liquid crystal layer interposed therebetween. When a distance from the top of the video signal line working as a light shielding film to the bottom of the liquid crystal layer is defined as d and a space between the centers of the video signal lines separating the pixel is defined as w, a relation of d≤0.3w is satisfied.