Two-Layer Color Filter Layout for Wider Gamut LCD Pixels

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Solution Overview

Problem

Existing liquid crystal display devices with a color filter on array (COA) system face challenges in achieving a broader color reproduction range due to thicker and darker color filters, which can lead to issues such as undercut formation during manufacturing and potential illumination failure.

Innovation Solution

The display device employs a two-layer color filter configuration, where the first layer is thinner and ensures adequate light exposure, while the second layer maintains color intensity, thereby preventing undercut formation and enhancing coverage by the insulating layer, thus improving display quality and color reproduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If color filters are made thicker to broaden color reproduction range, then color intensity is improved, but undercut formation occurs during manufacturing

Engineering Contradiction:

Improvecolor intensityVSAvoidundercut formation

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The color filter is divided into multiple layers (first color filter layer and second color filter layer) with different thicknesses. The first layer has smaller thickness to prevent undercut formation during manufacturing, while the second layer compensates to maintain overall color intensity. This segmentation allows each layer to be optimized for its specific function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the color filter structure have different thicknesses tailored to their specific requirements. The first color filter layer has smaller thickness in regions prone to undercut formation, while the second color filter layer has larger thickness in regions needing enhanced color intensity. This local quality optimization resolves the contradiction between manufacturing precision and color intensity.

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If color filters are made darker to improve color reproduction, then color saturation is improved, but light transmission is reduced

Engineering Contradiction:

Improvecolor saturationVSAvoidlight transmission

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The color filter is segmented into multiple layers with different optical densities. The first layer has lower optical density to allow sufficient light transmission, while the second layer has higher optical density to provide color saturation. This segmentation enables the system to achieve both light transmission and color saturation requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The color filter uses a composite structure of multiple layers with different material properties. The first layer uses material optimized for light transmission, while the second layer uses material optimized for color saturation. This composite approach allows the system to achieve both light transmission and color saturation simultaneously.

Inventive Principle:

Principle #40Composite materials

3Illumination intensity

If color filters are made thicker to ensure adequate color intensity, then color reproduction is improved, but insulating layer coverage becomes insufficient

Engineering Contradiction:

Improvecolor intensityVSAvoidinsulating layer coverage

Core Design Contradiction:

Illumination intensityVSArea of stationary object

Solution Approach 1:

The color filter is divided into multiple layers with different horizontal extensions. The first layer has smaller horizontal extension to allow adequate insulating layer coverage, while the second layer has larger horizontal extension to maintain color intensity. This segmentation resolves the contradiction between insulating layer coverage and color intensity.

Inventive Principle:

Principle #1Segmentation

4Manufacturing precision

If color filters are made thinner to improve light exposure, then manufacturing precision is improved, but color intensity is reduced

Engineering Contradiction:

Improvelight exposureVSAvoidcolor intensity

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The color filter is segmented into multiple layers where the first layer has smaller thickness to ensure adequate light exposure and manufacturing precision, while the second layer compensates with larger thickness to maintain overall color intensity. This segmentation allows the system to achieve both light exposure and color intensity requirements.

Inventive Principle:

Principle #1Segmentation

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 enhances color reproduction performance, reduces illumination failure risks, and maintains display quality by ensuring complete light transmission through the color filters, suitable for high-definition displays.

Implementation Method 1

ensures complete light transmission through the color filters

Methodology Applied

Scientific EffectLight transmission: Light

Implementation Method 2

first color filter provided between the semiconductor and the pixel electrode

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS20250362541A1Display device

Publication Date: 2025.11.27 JAPAN DISPLAY INC

AI summary

According to one embodiment, a display device includes a substrate, a semiconductor provided above the substrate, a pixel electrode electrically connected to the semiconductor, and a first color filter provided between the semiconductor and the pixel electrode. The first color filter includes a first layer and a second layer provided on the first layer and has the same color as that of the first layer.