Cellulose Ester Quarter Wave Plate with Normal Dispersion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing quarter wave plates exhibit wavelength dependence, leading to color shift and reduced contrast ratio in optical devices, and they often require additional protective films, while there is a need for a quarter wave plate with normal wavelength dispersion and reduced out-of-plane retardation for improved viewing quality in 3D display systems.
Innovation Solution
A quarter wave plate based on cellulose ester polymer with specific additives, such as a disk-like moiety with a fused ring structure, that achieves normal wavelength dispersion and reduced out-of-plane retardation, satisfying the equations Re(450)/Re(550)>1 and Re(650)/Re(550)<1, and having in-plane retardation of about 100-160 nm at 550 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional quarter wave plates are used, then they can provide basic polarization control, but they exhibit wavelength dependence causing color shift and reduced contrast ratio
Solution Approach 1:
The patent applies parameter changes by carefully controlling the stretching ratios and temperatures during film fabrication to achieve specific retardation values. By adjusting these processing parameters, the quarter wave plate achieves normal wavelength dispersion with reduced out-of-plane retardation, thereby minimizing color shift while maintaining polarization control functionality.
Solution Approach 2:
The patent uses composite materials by combining cellulose ester polymer with specific additives having disk-like or rod-like molecular structures. This composite approach allows the material to exhibit both the desired optical properties (normal dispersion) and mechanical properties, while the additive structure contributes to achieving the target retardation characteristics without excessive color shift.
2Reliability
If additional protective films are added to protect the polarizer, then protection is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the quarter wave plate to serve multiple functions simultaneously. The cellulose ester film with specific additives provides both optical compensation (quarter wave retardation) and protective functions for the polarizer. This multi-functionality eliminates the need for separate protective films, thereby reducing device complexity while maintaining reliability.
Solution Approach 2:
The patent merges the protective function with the optical compensation function into a single integrated film layer. By combining the quarter wave plate material with protective additives and structure, the invention creates a unified component that both compensates polarization and protects the underlying polarizer, reducing the total number of film layers required.
3Object-affected harmful factors
If out-of-plane retardation is reduced, then viewing quality is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by optimizing the stretching process parameters (temperature, stretch ratio, direction) to precisely control the molecular orientation and resulting retardation. By carefully adjusting these parameters, the film achieves reduced out-of-plane retardation while maintaining manufacturability through established processing techniques.
Solution Approach 2:
The patent uses composite materials with specific additive structures (disk-like or rod-like molecules) that contribute to reducing out-of-plane retardation. The additive structure interacts with the cellulose ester matrix to modify the optical properties, achieving the desired reduction in phase shift for off-axis light while maintaining compatibility with standard manufacturing processes.
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 cellulose ester polymer quarter wave plate with normal wavelength dispersion and low out-of-plane retardation enhances viewing quality and reduces phase shift in off-axis light, improving the performance of 3D glasses and other optical devices by maintaining image clarity and reducing light leakage.
Implementation Method 1
the phase retardation of light varies according to wavelength, causing color shift and contrast ratio reduction. This wavelength dependence (or dispersion) characteristic of the compensation film
Implementation Method 2
A wave plate can also be biaxial birefringent, where nx, ny, and nz all have different values; it is customarily referred to as a biaxial film
Implementation Method 3
The A-plate optical retarder has a refractive index profile of nx>nymz, wherein nx and ny represent in-plane refractive indices and nz represents the thickness-direction refractive index. Such a wave plate exhibits a positive in-plane retardation (Re)
Data Source
AI summary
The present invention pertains to an optical film for use as a quarter wave plate (QWP) having a normal wavelength dispersion curve. More specifically, this invention relates to a quarter wave plate based on cellulose ester polymer and fused ring additives.