Polarizing Plate Primer Layer Reduces Light Reflection

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Solution Overview

Problem

Liquid crystal display devices experience a decrease in brightness due to an air gap between the lower polarizing plate and the backlight unit, which existing brightness improvement methods fail to prevent effectively.

Innovation Solution

A high brightness polarizing plate is developed with a primer layer composed of a low-refractive polymer resin and fine hollow particles, applied on the protective film facing the backlight unit, which reduces light reflection and enhances anti-blocking characteristics without the need for additional coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a reflective polarizing plate is disposed around a lower polarizing plate to improve light use efficiency, then light use efficiency is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvelight use efficiencyVSAvoidstructure complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines the protective film and anti-blocking coating into a single integrated layer formed on the lower polarizing plate. This merged structure eliminates the need for separate reflective polarizing plates and additional coatings, reducing device complexity while maintaining light use efficiency through the anti-blocking properties of the integrated coating.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lower polarizing plate's protective film is designed to inherently provide anti-blocking characteristics through its specific refractive index and surface properties. This self-service approach eliminates the need for additional reflective polarizing plates or separate anti-blocking coatings, simplifying the overall device structure while maintaining functionality.

Inventive Principle:

Principle #25Self-service

2Reliability

If additional functional coating layers are formed to improve anti-blocking characteristics, then anti-blocking characteristics are improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveanti-blocking characteristicsVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The protective film and anti-blocking coating are merged into a single integrated layer formed directly on the lower polarizing plate. This combination eliminates the need for multiple sequential coating processes, reducing manufacturing complexity while achieving the desired anti-blocking characteristics through the layer's specific refractive index and surface properties.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The protective film is designed to simultaneously serve multiple functions: protecting the polarizer, providing anti-blocking characteristics, and controlling light reflection. This multi-functionality eliminates the need for separate functional coating layers, simplifying the manufacturing process while maintaining reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Illumination intensity

If the refractive index of the protective film is increased to reduce light reflection, then brightness is improved, but anti-blocking characteristics deteriorate

Engineering Contradiction:

ImprovebrightnessVSAvoidanti-blocking characteristics

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent optimizes the refractive index of the protective film to a specific range (1.45-1.55) that balances two opposing requirements: reducing light reflection to improve brightness while maintaining sufficient surface adhesion for anti-blocking characteristics. This parameter optimization allows the single layer to achieve both functions simultaneously without contradiction.

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 solution effectively increases the amount of light incident on the liquid crystal cell, improving the brightness of the liquid crystal display device while maintaining cost-effectiveness and simplicity in manufacturing.

Implementation Method 1

due to a difference in refractive indices between the air gap and the lower polarizing plate, light may be reflected

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

a primer layer including a low-refractive polymer resin and fine hollow particles may be formed on a side of the protective film

Methodology Applied

Scientific EffectAnti-reflective coating: Anti-Reflective Coating

Data Source

PatentUS10324243B2High brightness polarizing plate and liquid crystal display device including the same

Publication Date: 2019.06.18 LG CHEM LTD

AI summary

There are provided a high brightness polarizing plate and a liquid crystal display device including the high brightness polarizing plate as a lower polarizing plate. The high brightness polarizing plate includes: a polarizer; and a protective film disposed on a side of the polarizer, wherein the protective film faces a backlight unit, and a primer layer including a low-refractive polymer resin and fine hollow particles is formed on a side of the protective film opposite to a side thereof facing the polarizer.