Phase Difference Film with Controlled Nz Factor
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Solution Overview
Problem
Existing phase difference films formed using polymer materials result in thick films, and those formed with liquid crystal compounds do not achieve the desired Nz factor of 0<Nz<1, which is crucial for improved angular view characteristics in display devices.
Innovation Solution
A phase difference film is developed using a polymerizable liquid crystal compound with a mesogen group, where the order parameters in different directions are adjusted to specific ranges to achieve the desired Nz factor, with film thickness kept at 20.0 μm or less, and a single-layer structure is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polymer is used to form a phase difference film, then the film can be manufactured, but the thickness becomes too thick and the Nz factor cannot be controlled within the range of 0<Nz<1
Solution Approach 1:
The patent changes the material parameter from conventional polymers to liquid crystal compounds with specific molecular structures. By selecting liquid crystal compounds with particular mesogen groups and controlling their order parameters (Sx, Sy, Sz) within specific ranges, the patent achieves both thin film formation (20 μm or less) and precise control of the Nz factor within 0<Nz<1, resolving the contradiction between manufacturability and thickness control.
Solution Approach 2:
The patent uses composite liquid crystal compounds containing specific mesogen groups combined with polymerizable groups. This composite structure allows the material to exhibit both liquid crystal properties (for optical anisotropy and Nz factor control) and polymer properties (for film formation and stability), enabling thin film manufacturing with controlled optical characteristics.
2Length of stationary object
If a liquid crystal compound is used to reduce film thickness, then the thickness can be made thin, but the Nz factor cannot be controlled within the predetermined range of 0<Nz<1
Solution Approach 1:
The patent precisely controls the order parameters (Sx, Sy, Sz) of the liquid crystal compound's mesogen group within specific numerical ranges. By adjusting these order parameters through molecular structure design and processing conditions, the patent achieves precise control of the Nz factor within 0<Nz<1 while maintaining thin film thickness of 20 μm or less, resolving the contradiction between thickness reduction and Nz factor precision.
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 film achieves an Nz factor of more than 0 and less than 1, enhancing the angular view characteristics of display devices by optimizing the order parameters of the mesogen group in the phase difference film.
Implementation Method 1
A phase difference film having refractive index anisotropy is applied to various applications such as an antireflection film of a display device and an optical compensation film of a liquid crystal display device
Implementation Method 2
a phase difference film formed by using a composition including a polymerizable liquid crystal compound having a mesogen group
Implementation Method 3
an optical compensation film of a liquid crystal display device
Implementation Method 4
a phase difference film formed by using a composition including a polymerizable liquid crystal compound having a mesogen group
Data Source
AI summary
A phase difference film is formed by using a liquid crystal compound and that indicates an Nz factor of more than 0 and less than 1, an optical film with same, and a display device. The phase difference film is formed by using a composition including a polymerizable liquid crystal compound having a mesogen group, where an order parameter of the mesogen group in an in-plane slow axis direction of the phase difference film is set as Sx, an order parameter of the mesogen group in a direction orthogonal to the in-plane slow axis direction in a plane is set as Sy, and an order parameter of the mesogen group in a thickness direction of the phase difference film is set as Sz, in a case where the mesogen group has a rod or a disc shape, differing Expressions are satisfied.