Optically Anisotropic Layered Body for Angle-Dependent Reflection Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional circularly polarizing plates fail to effectively suppress external light reflection and coloring on image display devices when the display surface is viewed at an angle, leading to reduced visibility and aesthetic issues.
Innovation Solution
An optically anisotropic layered body comprising a combination of a first and second optically anisotropic layer with specific refractive index anisotropy, retardation, and NZ factor characteristics, which are optimized to minimize light reflection and coloring when the display surface is tilted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional circularly polarizing plate is provided on the display surface, then reflection of external light can be suppressed when the display surface is observed in a front direction, but reflection of external light and coloring occur when the display surface is observed in a tilt direction
Solution Approach 1:
The patent divides the optically anisotropic film into multiple layers (first optically anisotropic layer and second optically anisotropic layer) with different retardation characteristics. This segmentation allows each layer to contribute differently to the overall optical performance, enabling suppression of reflection across a wider range of observation angles while maintaining the benefits of conventional circularly polarizing plates in front-direction viewing.
Solution Approach 2:
The patent uses a composite structure combining a linear polarizer with multiple optically anisotropic layers having different retardation values. This composite material approach creates a circularly polarizing plate with enhanced optical properties that can suppress external light reflection effectively both in front direction and tilt direction observations, resolving the contradiction between front-direction performance and multi-angle adaptability.
2Object-affected harmful factors
If a positive C film is provided in the circularly polarizing plate, then coloring of the display surface when observed in a tilt direction is largely decreased, but light is still slightly reflected and coloring may be observed
Solution Approach 1:
The patent precisely controls the retardation parameters of the optically anisotropic layers, specifying that the first layer has retardation of 137-152 nm and the second layer has retardation of 70-90 nm. By optimizing these parameter ranges and their combinations, the patent achieves effective suppression of both reflection and coloring across various observation angles, moving beyond the limited improvement of simple positive C film insertion.
Solution Approach 2:
The patent combines multiple optically anisotropic layers with different retardation characteristics to create a composite structure that achieves superior optical performance. This composite approach allows simultaneous optimization for both front-direction and tilt-direction viewing, achieving effective suppression of reflection and coloring that cannot be achieved with single-layer films.
3Object-affected harmful factors
If the in-plane retardation of the first optically anisotropic layer and thickness direction retardation of the second optically anisotropic layer are optimized, then external light reflection and coloring are suppressed, but the device structure becomes more complex
Solution Approach 1:
The patent segments the optically anisotropic function into two separate layers with distinct retardation characteristics. The first layer provides primary optical anisotropy (137-152 nm) while the second layer provides supplementary anisotropy (70-90 nm). This segmentation allows independent optimization of each layer's properties to achieve comprehensive reflection and coloring suppression without requiring a single complex multi-functional layer.
Solution Approach 2:
The patent optimizes specific parameter ranges for each layer: the first layer has in-plane retardation of 137-152 nm and the second layer has thickness direction retardation of 70-90 nm. By controlling these parameters within specific ranges, the patent achieves effective suppression of reflection and coloring while maintaining a relatively simple two-layer structure that is manufacturable and integrates well with conventional display device architecture.
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 significantly reduces external light reflection and coloring on image display devices when viewed at an angle, enhancing visibility and aesthetic quality by using a layered structure with precise refractive index and retardation properties.
Implementation Method 1
a refractive index nx2 in a direction which gives a maximum refractive index among in-plane directions of the second optically anisotropic layer, a refractive index ny2 in a direction, among the in-plane directions of the second optically anisotropic layer, perpendicular to the direction giving the nx2, and a thickness direction refractive index nz2 of the second optically anisotropic layer satisfy the formula (1), nz2>nx2≥ny2
Implementation Method 2
an in-plane retardation Re1(450) of the first optically anisotropic layer at a wavelength of 450 nm, an in-plane retardation Re1(550) of the first optically anisotropic layer at a wavelength of 550 nm, and an in-plane retardation Re1(650) of the first optically anisotropic layer at a wavelength of 650 nm satisfy the formula (2), Re1(450)>Re1(550)>Re1(650)
Data Source
AI summary
An optically anisotropic layered body including a first optically anisotropic layer and a second optically anisotropic layer, wherein each of refractive indices of the second optically anisotropic layer, in-plane retardations of the first optically anisotropic layer, thickness direction retardations of the second optically anisotropic layer, in-plane retardations of the optically anisotropic layered body, NZ factors of the optically anisotropic layered body, and thickness direction retardations Rth of the optically anisotropic layered body satisfies specific relationships.