Thin Polarizer Configuration for Wide-Viewing Angle LCDs

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Solution Overview

Problem

Conventional liquid crystal display devices with in-plane switching (IPS) mode suffer from limited viewing angles and color differences when viewed through polarized sunglasses, leading to reduced visibility and contrast ratio, especially when used outdoors due to issues with polarizer thickness and moisture sensitivity.

Innovation Solution

A liquid crystal display device with a thin polarizer configuration, including a first polarizer with optical compensation films and a phase retardation film, and a second polarizer with protective films, which maintains optical properties and prevents color differences across viewing angles by converting linearly polarized light to circularly polarized light, thereby ensuring consistent image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a conventional IPS mode LCD device uses a thick polarizer to maintain optical properties, then the optical performance is improved, but the viewing angle is limited and color differences occur when viewed through polarized sunglasses

Engineering Contradiction:

Improveoptical performanceVSAvoidviewing angle

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The polarizer is divided into multiple thin polarizing films instead of using a single thick polarizer. This segmentation allows the device to maintain optical performance while achieving wide viewing angles and eliminating color differences when viewed through polarized sunglasses.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple thin polarizing films are combined in a composite structure with specific orientations. This composite configuration maintains the optical properties of a thick polarizer while enabling wide viewing angles and compatibility with polarized sunglasses by distributing the polarization function across multiple layers.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If a thick polarizer is used in IPS mode LCD, then optical properties are maintained, but the device shows color differences and reduced visibility when viewed through polarized sunglasses outdoors

Engineering Contradiction:

Improveoptical propertiesVSAvoidcolor differences and reduced visibility

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The polarizer is segmented into multiple thin films that can be independently oriented. This segmentation allows the device to maintain stable optical properties while eliminating color differences when viewed through polarized sunglasses by creating a multi-layer polarization structure that is compatible with external polarized filters.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polarization structure parameters are changed from a single thick layer to multiple thin layers with specific thicknesses and orientations. This parameter change maintains optical properties while eliminating the harmful effect of color differences when viewed through polarized sunglasses.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If multiple optical compensation films are added to achieve wide viewing angles, then viewing angle is improved, but the polarizer thickness increases and moisture sensitivity increases

Engineering Contradiction:

Improveviewing angleVSAvoidpolarizer thickness

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The polarizer is segmented into multiple thin films instead of using a single thick polarizer or adding multiple compensation films. This segmentation achieves wide viewing angles while keeping the overall structure simple and reducing moisture sensitivity by eliminating the need for thick polarizers and additional compensation layers.

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

The solution provides a liquid crystal display device with wide-viewing angles and high-quality images, maintaining consistent color impression and contrast ratio even when viewed through polarized sunglasses, while reducing the thickness of the polarizer and enhancing visibility outdoors.

Implementation Method 1

the phase retardation film has a retardation value of λ/4

Methodology Applied

Scientific EffectPhase retardation: Birefringence

Implementation Method 2

Light vibrating in a direction parallel to the absorption axis is absorbed by the polarizing film, and light vibrating in a direction perpendicular to the absorption axis is selectively transmitted

Methodology Applied

Scientific EffectPolarization absorption: Polarisation

Data Source

PatentUS9298040B2Liquid crystal display device with wide-viewing angle

Publication Date: 2016.03.29 LG DISPLAY CO LTD

AI summary

An LCD device includes a liquid crystal panel; a first polarizer attached to a first surface of the liquid crystal panel and including a first polarizing film, first and second optical compensation films disposed on one surface of the first polarizing film, and a phase retardation film, a protective film and a functional film disposed on another surface of the first polarizing film; and a second polarizer attached to a second surface of the liquid crystal panel and including a second polarizing film, an inner protective film disposed on one surface of the second polarizing film, and an outer protective film disposed on another surface of the second polarizing film, wherein the first polarizing film is disposed between the phase retardation film and the liquid crystal panel, and the phase retardation film has a retardation value of λ/4.