Quarter Wave Plate Retardation for OLED Color Shift Prevention
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Solution Overview
Problem
OLED devices suffer from a color shift phenomenon due to the retardation of the lower TAC layer and spectral distribution properties of the Quarter Wave Plate (QWP), leading to degraded image quality.
Innovation Solution
A display device incorporating a Poly-Vinyl Acetate (PVA) layer for linear polarization and a Quarter Wave Plate (QWP) with an in-plane retardation value below 140 nm, optimized with iodine molecular weight adjustments to prevent color shifts and enhance reflective visibility and reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional Quarter Wave Plate (QWP) with standard retardation is used, then the OLED device achieves basic light polarization function, but color shift phenomenon occurs and image quality is degraded
Solution Approach 1:
The patent changes the in-plane retardation parameter of the QWP from conventional values (typically 150-200nm) to a specific range of 80-120nm. This parameter modification adjusts the spectral distribution characteristics of the QWP, preventing the blue color shift phenomenon while maintaining effective circular polarization functionality, thereby improving image quality without sacrificing polarization performance
Solution Approach 2:
The patent introduces a dual-QWP structure where a first QWP and second QWP are stacked with different retardation values and orientation angles. This creates a dynamic optical system where the combined retardation effect can be precisely controlled to compensate for spectral distribution issues, eliminating color shifts while maintaining polarization efficiency across different viewing conditions
2Device complexity
If the lower TAC layer and conventional QWP are used together, then the polarizing film structure is simple, but spectral distribution properties cause color shift and degrade visibility
Solution Approach 1:
The patent modifies the retardation parameter of the QWP to 80-120nm, which changes the spectral transmission characteristics. This parameter adjustment optimizes the interaction between the QWP and TAC layer, reducing unwanted blue color shifts while enhancing reflective visibility through improved spectral distribution, all within the existing simple film structure
Solution Approach 2:
The patent creates a composite polarizing film structure combining TAC layers with a specially designed QWP having 80-120nm retardation. This composite structure leverages the complementary optical properties of each material - the TAC layers provide structural support and linear polarization while the optimized QWP provides circular polarization with improved spectral characteristics, achieving enhanced visibility without increasing structural complexity
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 prevents color shifts and enhances image quality by improving reflective visibility and reflectance while maintaining chrominance, thereby addressing the limitations of existing OLED devices.
Implementation Method 1
a Poly-Vinyl Acetate (PVA) layer configured to linearly polarize external light
Implementation Method 2
a Quarter Wave Plate (QWP) configured to circularly polarize light
Data Source
AI summary
Embodiments relate to a display device for enhancing image quality. The disclosed display device includes: a display panel configured to display an image; a Poly-Vinyl Acetate (PVA) layer configured to linearly polarize external light; and a Quarter Wave Plate (QWP) configured to circularly polarize light where the QWP has an in-plane retardation value of below 140 nm.