Color Filter Light Blocking Layer Prevents Mixing

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Solution Overview

Problem

Conventional liquid crystal displays (LCDs) using color filters suffer from low light efficiency and color reproducibility issues due to the absorption and mixing of light by color conversion layers, which reduces the overall image quality.

Innovation Solution

A color filter design incorporating a substrate with separate pixel regions, a first color conversion layer converting incident light to red light, a second color conversion layer converting incident light to green light, and a barrier wall with a light blocking layer to prevent light mixing, along with a planarization layer to ensure even light distribution, enhancing light efficiency and color purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If color filters are used to generate color light in LCD, then color reproduction is achieved, but light efficiency is reduced by 1/3

Engineering Contradiction:
Improvelight efficiencyVSAvoidcolor reproduction quality
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent extracts the color conversion function from the traditional color filter layer and relocates it to a separate color conversion layer positioned closer to the light source. This extraction allows the color conversion process to occur before light enters the liquid crystal layer, eliminating the need for light to pass through color filters twice and thereby improving light efficiency while maintaining color reproduction quality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the spatial arrangement of color conversion components from being integrated within the color filter layer to being positioned in a separate layer closer to the light source. This dimensional repositioning creates a new optical path where color conversion happens earlier in the light transmission sequence, resolving the contradiction between light efficiency and color reproduction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If quantum dot-color conversion layer is used to generate color light, then light efficiency is improved, but light emitted in various directions causes color mixing between adjacent pixels

Engineering Contradiction:
Improvelight efficiencyVSAvoidcolor purity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent introduces a light shielding layer as an intermediary component positioned between adjacent color conversion layers. This mediator blocks oblique light from reaching adjacent pixels, preventing color mixing while allowing the quantum dot color conversion layer to maintain its high light efficiency advantage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the color conversion structure by positioning separate color conversion layers for different colors (red, green, blue) at different locations relative to the light source. This segmentation, combined with the light shielding layer, prevents cross-contamination of light between adjacent color regions, ensuring color purity while maintaining the benefits of quantum dot color conversion.

Inventive Principle:
Principle #1Segmentation

3Illumination intensity

If color conversion layers are positioned close to light source, then light efficiency is improved, but light mixing between adjacent pixels increases

Engineering Contradiction:
Improvelight efficiencyVSAvoidlight mixing
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The light shielding layer serves as a mediator that selectively blocks harmful oblique light from reaching adjacent pixels while allowing useful light to pass through. This intermediary component resolves the contradiction by eliminating the harmful light mixing effect without compromising the light efficiency gains from positioning color conversion layers near the light source.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality control by positioning light shielding structures specifically at locations where light mixing problems occur (between adjacent color conversion layers), rather than applying a uniform solution across the entire display. This localized approach maintains light efficiency in active regions while preventing color mixing at boundaries.

Inventive Principle:
Principle #3Local quality

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 significantly improves light efficiency and color reproducibility by preventing light mixing between adjacent color conversion layers, resulting in better image quality and reduced power consumption.

Implementation Method 1

a first color conversion layer, over the first pixel region, arranged to convert incident light to light of a first color

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a second color conversion layer, over the second pixel region, arranged to convert the incident light to light of a second color

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 3

a light blocking layer extending continuously on a bottom surface and a side surface of the barrier wall

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3282310B1Method of manufacturing a color filter
Publication Date: 2023.01.25 SAMSUNG DISPLAY CO LTD
  • EP3282310B1 patent drawingFigure 1
  • EP3282310B1 patent drawingFigure 2
  • EP3282310B1 patent drawingFigure 3A

AI summary

A color filter includes a substrate, a first color conversion layer, a second color conversion layer, a barrier wall, and a light blocking layer. The substrate includes a first pixel region spaced from a second pixel region. The first color conversion layer is on the first pixel region and converts incident light to light of a first color. The second color conversion layer is on the second pixel region and converts the incident light to light of a second color. The barrier wall is between the first and second color conversion layers over the substrate. The light blocking layer extends continuously on a bottom surface and a side surface of the barrier wall, and the bottom surface faces the substrate.