Circularly Polarizing Plate Ultraviolet Blocking

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Solution Overview

Problem

Conventional circularly polarizing plates fail to effectively block ultraviolet rays in the 380 to 400 nm range, which can affect the durability of organic light emitting devices and observer health, while attempts to block these rays using ultraviolet absorbers or light stabilizers can impact display quality and durability.

Innovation Solution

A circularly polarizing plate design incorporating a polarizer and a phase difference layer with controlled optical characteristics to selectively block ultraviolet rays in the 380 to 400 nm range without using additives like ultraviolet absorbers or light stabilizers, ensuring stable durability and display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional ultraviolet absorbers or light stabilizers are added to the protective film, then ultraviolet rays below 380 nm are blocked, but ultraviolet rays in the 380 to 400 nm range are not efficiently blocked and display quality may be affected

Engineering Contradiction:

Improveultraviolet ray blockingVSAvoiddurability against 380-400 nm ultraviolet rays

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the wavelength blocking parameters by incorporating ultraviolet absorbers with specific maximum absorption wavelengths (385 nm to 400 nm) into the protective film, thereby extending the blocking range to cover the 380-400 nm ultraviolet region that conventional absorbers miss

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material composition by combining multiple ultraviolet absorbers with different maximum absorption wavelengths (e.g., 385 nm, 390 nm, 395 nm, 400 nm) within the protective film to achieve comprehensive ultraviolet blocking across the 380-400 nm range while maintaining display quality

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If ultraviolet absorbers or light stabilizers are incorporated into the protective film or circularly polarizing plate, then ultraviolet blocking is improved, but display quality may be affected due to blocking of short wavelength visible light

Engineering Contradiction:

Improveultraviolet ray blockingVSAvoiddisplay quality

Core Design Contradiction:

Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent applies local quality by selecting ultraviolet absorbers with maximum absorption wavelengths specifically in the 385-400 nm range, which targets the harmful ultraviolet region while minimizing absorption of visible light (above 400 nm), thereby protecting display quality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent carefully controls the parameter of maximum absorption wavelength of the ultraviolet absorbers to be within 385-400 nm, creating a clear separation between the blocking range (ultraviolet) and the transmission range (visible light), thus avoiding display quality degradation

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If ultraviolet absorbers or light stabilizers are contained in the layer formed by liquid crystal compound, then ultraviolet blocking is achieved, but the entire durability of the circularly polarizing plate is adversely affected

Engineering Contradiction:

Improveultraviolet ray blockingVSAvoidcircularly polarizing plate durability

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The patent extracts the ultraviolet absorption function from the liquid crystal layer and relocates it to the protective film layer, where ultraviolet absorbers are incorporated specifically in the protective film rather than in the liquid crystal compound layer, thereby preserving the durability of the circularly polarizing plate while achieving ultraviolet blocking

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the functional layers by placing ultraviolet absorbers specifically in the protective film layer (separate from the liquid crystal phase difference layer), allowing the liquid crystal layer to maintain its optical performance and durability while the protective film handles ultraviolet absorption

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 effectively blocks harmful ultraviolet rays, maintaining the durability and display quality of organic light emitting devices without compromising image quality or causing color shifts.

Implementation Method 1

the phase difference layer is designed to have optical characteristics controlled for light in the ultraviolet region, particularly at any one wavelength in a range of 380 nm to 400 nm

Methodology Applied

Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 2

The circularly polarizing plate is capable of securing stable durability in itself while effectively blocking ultraviolet rays affecting the durability of the device

Methodology Applied

Scientific EffectRadiation blocking: Absorption (EM radiation)

Data Source

PatentUS11314007B2Circularly polarizing plate

Publication Date: 2022.04.26 SHANJIN OPTOELECTRONICS (SUZHOU) CO LTD

AI summary

Provided is a circularly polarizing plate and a display device that includes the circularly polarizing plate. The circularly polarizing plate can be applied to a display device such as an organic light emitting display device to minimize blocking of light in the visible light region affecting image quality while blocking harmful ultraviolet rays appropriately and also has excellent durability.