Circular Polarizing Plate UV Blocking via Phase Difference Layer
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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 existing methods for adding ultraviolet absorbers can impact display quality and durability.
Innovation Solution
A circularly polarizing plate design featuring a base film with specific phase difference characteristics, including a planar phase difference of 5 nm or less and a thickness direction phase difference of 10 nm or more, combined with a polarizer, to selectively block ultraviolet rays without using ultraviolet absorbers or light stabilizers.
Engineering Contradictions & Design Principles
Engineering 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 380-400 nm range are not efficiently blocked and display quality may be affected
Solution Approach 1:
The patent changes the wavelength blocking parameters by using a phase difference layer with specific optical properties (retardation value of 90-300 nm at 550 nm) to block ultraviolet rays in the 380-400 nm range, complementing the conventional absorbers that block rays below 380 nm. This parameter-based approach achieves comprehensive UV blocking without affecting visible light transmission and display quality
Solution Approach 2:
The patent creates a composite structure combining a polarizer, conventional protective film with ultraviolet absorbers, and an additional phase difference layer with specific retardation properties. This composite design integrates multiple functional layers, each contributing to different aspects of ultraviolet protection while maintaining display performance
2Ease of operation
If a phase difference film is laminated on the circularly polarizing plate to improve compensation characteristics, then viewing angle characteristics are improved, but process complexity and cost increase
Solution Approach 1:
The patent merges the compensation function into the existing phase difference layer by selecting materials and configuring the layer to provide both the necessary phase difference for circular polarization and the additional compensation needed for wide viewing angle characteristics. This integration eliminates the need for a separate compensation film, simplifying the structure and manufacturing process
Solution Approach 2:
The phase difference layer is designed to serve multiple functions simultaneously: it provides the quarter-wave retardation needed for circular polarization conversion and also delivers the compensation characteristics required for improved viewing angle performance. This multi-functionality reduces the total number of components and simplifies the overall device structure
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 excellent durability and antireflection characteristics at viewing angles, maintaining display quality while ensuring process simplicity and cost competitiveness by effectively blocking harmful ultraviolet rays without compromising image quality.
Implementation Method 1
the phase difference layer has a transmittance of 3% or less for light having a wavelength of 385 nm... the phase difference layer selectively block ultraviolet rays without using ultraviolet absorbers or light stabilizers
Implementation Method 2
a so-called circularly polarizing plate basically comprising a polarizer and a phase difference layer can be used for preventing external light reflection
Data Source
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AI summary
The present application relates to a circularly polarizing plate and a use thereof. The present application can provide a circularly polarizing plate, which 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. In addition, the present application can provide a circularly polarizing plate having excellent compensation characteristics at a viewing angle while ensuring process simplification and cost competitiveness.