OLED Polarization Structure Minimizing Color Shift

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Solution Overview

Problem

Conventional polarization structures in OLED displays are thick, leading to a color shift phenomenon when the viewing angle increases, which degrades image quality and contrast ratio.

Innovation Solution

A polarization structure comprising a retardation layer, a first and second uniaxial optical compensation layer, and polarizing layers, with a coatable inverse wavelength dispersion type retardation layer and coatable uniaxial optical compensation layers, is used to create a phase difference between polarization components and reduce reflection, thereby minimizing thickness and color shift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a conventional polarization structure is used, then the structure provides basic polarization function, but the thickness is large causing color shift phenomenon at increased viewing angles

Engineering Contradiction:

Improvethickness of polarization structureVSAvoidcolor shift phenomenon

Core Design Contradiction:

Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The polarization structure is divided into multiple functional layers: a first uniaxial optical compensation layer, a second uniaxial optical compensation layer, a polarizing layer positioned between them, and a quarter-wave retardation layer. Each layer has specific optical properties (different slow axis orientations and retardation values) that work together to reduce overall thickness while eliminating color shift through coordinated optical compensation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite optical layers with different material properties - combining uniaxial optical compensation materials with specific slow axis orientations (0° and 90° relative to each other) and a quarter-wave retardation material. This composite structure achieves superior optical performance with reduced thickness compared to conventional single-material polarization structures.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If the polarization structure thickness is reduced, then color shift is minimized, but the structural complexity increases with multiple layers

Engineering Contradiction:

Improvecolor shift phenomenonVSAvoidnumber of layers in polarization structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention merges multiple optical compensation functions into a coordinated multi-layer system where the first and second uniaxial optical compensation layers work together with the polarizing layer and quarter-wave retardation layer. This integration achieves color shift elimination while maintaining a compact overall structure that is simpler in functional organization despite having multiple layers.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If a thicker polarization structure is used, then manufacturing is simpler, but external light reflection increases degrading contrast ratio

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidexternal light reflection

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention applies specific optical properties to specific layers: the first uniaxial optical compensation layer has its slow axis oriented at 0°, the second at 90°, and a quarter-wave retardation layer is positioned at a specific location. This localized optimization of optical properties in each layer reduces external light reflection through coordinated optical interference, improving contrast ratio without requiring overall thickness increase.

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 proposed polarization structure effectively reduces external light reflection and color shift, improving the contrast ratio and maintaining image quality across varying viewing angles with a thinner, more simplified design.

Implementation Method 1

The retardation layer may be configured to create a phase difference between two polarization components of an incident light

Methodology Applied

Scientific EffectBirefringence: Birefringence

Implementation Method 2

The first uniaxial optical compensation layer may include an O-plate, and the second uniaxial optical compensation layer may include a coatable O-plate

Methodology Applied

Scientific EffectOptical interference: Interference

Data Source

PatentUS8975812B2Polarization structure, method of manufacturing a polarization structure and organic light emitting display device having a polarization structure

Publication Date: 2015.03.10 SAMSUNG DISPLAY CO LTD

AI summary

A polarization structure for a display device is disclosed. In one embodiment, the structure includes a retardation layer, a first polarizing layer, a first uniaxial optical compensation layer, a second polarizing layer and a second uniaxial optical compensation layer. The retardation layer may be configured to create a phase difference between two polarization components of an incident light. The first polarizing layer may be disposed on the retardation layer. The first uniaxial optical compensation layer may be disposed on the first polarizing layer. The second polarizing layer may be disposed on the first uniaxial optical compensation layer. The second uniaxial optical compensation layer may be disposed between the first polarizing layer and the first uniaxial optical compensation layer or between the first polarizing layer and the second polarizing layer.