Optical Film with Phase Delay Layer for Display Reflection

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Solution Overview

Problem

Conventional optical films used in flat panel displays have weak optical durability and are thick, leading to compromised display quality due to external light reflection issues, particularly in light-emitting displays where metal electrodes cause visibility and contrast ratio deterioration.

Innovation Solution

An optical film comprising a polarization film made from a melt-blended polymer resin and dichroic dye, combined with a phase delay layer of anisotropic liquid crystals, which effectively circularly polarizes light to prevent external light reflection by using a λ/4 or λ/2 phase delay configuration, thereby enhancing display quality and reducing film thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional optical films are used to prevent external light reflection, then display quality is improved, but the film thickness increases and optical durability deteriorates

Engineering Contradiction:
Improveoptical durabilityVSAvoidfilm thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent changes the material parameters by using a polymer resin with specific properties (polymerization shrinkage of 5-20%, refractive index matching the liquid crystal layer) and controlling the thickness of each layer (polarization film: 5-50 μm, phase delay layer: 10-100 μm). This allows achieving the required optical durability and performance while maintaining reduced overall thickness compared to conventional optical films.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure consisting of a polarization film made from polymer resin and dichroic dye, combined with a phase delay layer containing anisotropic liquid crystals. This composite material approach enables the film to achieve both thin profile and high optical durability by leveraging the complementary properties of different materials working together.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional optical films are used to reduce external light reflection, then display quality is improved, but the film thickness increases

Engineering Contradiction:
Improvedisplay qualityVSAvoidfilm thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent divides the optical film into two functional segments: a polarization film (5-50 μm thick) made from polymer resin and dichroic dye, and a phase delay layer (10-100 μm thick) containing anisotropic liquid crystals. This segmentation allows each layer to be optimized for its specific function while maintaining a reduced overall thickness compared to conventional single-layer optical films.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes the thickness parameters of each layer and the material properties (refractive index, polymerization shrinkage) to achieve the desired optical performance. By controlling the polymerization shrinkage within 5-20% and selecting appropriate thickness ranges, the film achieves thin profile while maintaining high display quality.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If metal electrodes are used in light emitting displays, then device functionality is achieved, but external light reflection increases causing visibility and contrast ratio deterioration

Engineering Contradiction:
Improvedevice functionalityVSAvoidexternal light reflection
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of external light reflection from metal electrodes into a beneficial solution by applying a polarization film with specific optical properties. The film's refractive index is designed to match the liquid crystal layer, and its thickness and material composition are optimized to minimize reflection while maintaining the functionality of the metal electrodes for device operation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the optical parameters of the film (refractive index, thickness, polarization properties) to reduce external light reflection. By controlling the polymerization shrinkage of the polymer resin to 5-20% and selecting appropriate thickness ranges, the film achieves optimal optical performance that eliminates reflection issues while preserving electrode functionality.

Inventive Principle:
Principle #35Parameter changes

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 film significantly improves display characteristics by minimizing external light reflection, maintaining high optical properties, and reducing the overall thickness of the display device, while ensuring excellent light transmittance and mechanical strength.

Implementation Method 1

a polarization film made from a melt-blended polymer resin and dichroic dye

Methodology Applied
Scientific EffectDichroism: Dichroic Filter

Implementation Method 2

the linear polarized light is shifted into circularly polarized light using a polarizing plate and a retardation film

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 3

a phase delay layer of anisotropic liquid crystals, which effectively circularly polarizes light to prevent external light reflection by using a λ/4 or λ/2 phase delay configuration

Methodology Applied
Scientific EffectBirefringence: Birefringence

Data Source

PatentEP2960693B1Optical film, manufacturing method thereof, and display device
Publication Date: 2023.01.11 SAMSUNG ELECTRONICS CO LTD
  • EP2960693B1 patent drawingFigure 1
  • EP2960693B1 patent drawingFigure 2
  • EP2960693B1 patent drawingFigure 3

AI summary

An optical film includes a polarization film including a polymer resin and a dichroic dye, and a phase delay layer disposed on the polarization film and including a liquid crystal.