Optical Filter Color Shift Reduction via Segmented Absorbing and Diffusing Layers

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Solution Overview

Problem

Conventional display devices, particularly LCDs, suffer from significant color shift and limited viewing angle due to variations in light intensity and color as the viewing angle increases, which affects image quality and contrast ratio.

Innovation Solution

An optical filter with a color shift-reducing pattern is implemented, featuring a combination of light-absorbing materials, such as green wavelength-absorbing materials, cyan wavelength-absorbing materials, orange wavelength-absorbing materials, and black materials, along with light-diffusing materials like beads, to minimize color shift by absorbing specific wavelengths and diffusing light uniformly across the viewing angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional LCD structure is used, then light weight and low power consumption are achieved, but color shift and viewing angle are limited

Engineering Contradiction:
Improveviewing angleVSAvoidcolor shift
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The optical filter is divided into multiple regions with different light-absorbing materials, each targeting specific wavelength ranges. This segmentation allows different parts of the filter to address different aspects of color shift at various viewing angles, resolving the contradiction between wide viewing angle and color accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the optical filter have different light-absorbing properties tailored to local viewing angle requirements. The filter applies specific light-absorbing materials in specific areas to correct color shift locally, maintaining image quality across the entire viewing range without compromising overall performance.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If light-absorbing materials are added to reduce color shift, then color accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvecolor shiftVSAvoidoptical filter structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Multiple light-absorbing materials with different wavelength absorption characteristics are combined in a single optical filter structure. This merging approach integrates multiple color correction functions into one component, improving color accuracy without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical filter serves multiple functions simultaneously: it corrects color shift across different viewing angles, maintains light transmission efficiency, and provides broad-spectrum wavelength filtering. This multi-functionality reduces the need for separate components, keeping the overall device complexity manageable.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If multiple wavelength-absorbing materials are used, then color shift is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvecolor shiftVSAvoidoptical filter fabrication
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The optical filter uses composite material structures where different light-absorbing materials are integrated into a unified filter matrix. This composite approach allows multiple wavelength absorption capabilities to be achieved through material composition rather than separate physical layers, simplifying the manufacturing process while maintaining color correction effectiveness.

Inventive Principle:
Principle #40Composite materials

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 optical filter effectively reduces color shift and enhances viewing angle, ensuring improved image quality and uniform brightness across different angles by absorbing specific wavelengths and diffusing light, thereby mitigating the effects of color change and luminance variation.

Implementation Method 1

a first and a second partial area, in which only the first partial area includes the light-absorbing material

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

only the second partial area includes the light-diffusing material

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP2317376B1Optical filter for display device and display device having the same
Publication Date: 2015.04.01 SAMSUNG CORNING PRECISION MATERIALS CO LTD
  • EP2317376B1 patent drawingFigure 1
  • EP2317376B1 patent drawingFigure 2
  • EP2317376B1 patent drawingFigure 3

AI summary

An optical filter provided in front of a display panel of a display devise includes a background layer (10) and a color shift-reducing pattern formed to a predetermined thickness at the background layer (10). The color shift-reducing pattern has a plurality of partial areas (21,23), and at least two partial areas (21,23) of the plurality of partial areas (21,23) have different light absorptivities and/or light diffusivities. The at least two partial areas (21,23) may contain different amounts of a light-absorbing material that cause the different light-absorptivities and/or different amounts of a light-diffusing material that cause the different light diffusivities, The color shift-reducing pattern may have first and second partial areas (21,23), in which only the first partial area (21) may contain the light-absorbing material, and only the second partial area (23) may contain the light-diffusing material. The light-absorbing material may include a green wavelength-absorbing material that absorbs light having green wavelengths from 510nm to 560nm. The light-diffusing material may include light-diffusing beads.