Optical Film with Dual Phase Delay Layers for Wavelength Dependency
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Solution Overview
Problem
Optical films used in display devices, such as OLEDs and LCDs, suffer from wavelength-dependent performance, leading to deteriorated visibility and contrast due to exterior light reflection, which existing solutions like polarizers and retardation films fail to adequately address across all wavelengths.
Innovation Solution
An optical film comprising a polarization layer, a first phase delay layer with a liquid crystal aligned at specific angles, and a second phase delay layer, where the first phase delay layer has in-plane retardation and the second phase delay layer has negative birefringence, arranged to shift linearly polarized light into circularly polarized light, reducing wavelength dependency and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single retardation film is used to shift linearly polarized light to circularly polarized light, then the film can effectively reduce exterior light reflection for a specific wavelength, but the effect deteriorates for other wavelengths causing wavelength dependency
Solution Approach 1:
The patent divides the single retardation film into multiple phase delay layers with different retardation characteristics. The first phase delay layer has in-plane retardation while the second phase delay layer has thickness-direction retardation, allowing each layer to address different wavelength ranges and reduce overall wavelength dependency across the visible spectrum
Solution Approach 2:
The patent combines multiple phase delay layers with different optical properties to create a composite optical film. The first phase delay layer includes a liquid crystal layer with positive birefringence, while the second phase delay layer uses a polymer material with negative birefringence, creating a composite structure that achieves broadband wavelength independence
2Object-affected harmful factors
If a polarizer and retardation film are used to prevent exterior light reflection, then visibility and contrast ratio improve, but the device complexity increases
Solution Approach 1:
The patent merges the functions of multiple phase delay layers into a single integrated optical film structure. The first and second phase delay layers are combined in a specific arrangement where the optical axis of the first layer is at 45 degrees to the polarization direction and the second layer has its optical axis perpendicular to the first layer, achieving multiple functions in one compact structure
Solution Approach 2:
The composite optical film structure serves multiple functions simultaneously: it acts as a polarizer, provides wavelength-independent retardation, reduces exterior light reflection, and maintains image quality across the visible spectrum, eliminating the need for separate components
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 optical film effectively reduces wavelength dependency, enhancing image quality and visibility by uniformly managing reflectance across the visible spectrum, as demonstrated by reduced reflectance and improved color shift in comparison to conventional films.
Implementation Method 1
a first phase delay layer positioned on one side of the polarization layer and including a liquid crystal, where the first phase delay layer has an optical axis defining an angle of about 17 degrees to about 27 degrees or about −27 degrees to about −17 degrees relative to a transmissive axis of the polarization layer
Implementation Method 2
the liquid crystal may be arranged along the optical axis of the first phase delay layer
Implementation Method 3
the second phase delay layer has negative birefringence, arranged to shift linearly polarized light into circularly polarized light
Data Source
AI summary
An optical film including a polarization layer, a first phase delay layer positioned on a side of the polarization layer and including a liquid crystal, and a second phase delay layer positioned on a side of the first phase delay layer, where the first phase delay layer has an optical axis defining an angle of about 17 degrees to about 27 degrees or about −27 degrees to about −17 degrees relative to a transmissive axis of the polarization layer, and the second phase delay layer has an optical axis defining an angle of about 85 degrees to about 95 degrees relative to the transmissive axis of the polarization layer.