Polymerised Liquid Crystal Film for Achromatic OLED Anti-Reflection
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Solution Overview
Problem
Existing polymerisable liquid crystal materials for optical films exhibit wavelength-dependent retardation, poor thermal durability, and high synthesis costs, making them unsuitable for mass production and effective anti-reflection in OLED displays.
Innovation Solution
A polymerisable LC medium comprising di- or multireactive mesogenic compounds with chiral compounds of (S)- and (R)-configuration and photoisomerisable groups, allowing for the production of achromatic QWPs with flat optical dispersion in a single layer, enhancing thermal stability and reducing synthesis costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If highly conjugated substituents are used to produce reverse optical dispersion, then reverse optical dispersion is achieved, but UV absorption increases and thermal durability decreases
Solution Approach 1:
The patent changes the molecular structure parameters by using non-conjugated or less conjugated substituents instead of highly conjugated ones, thereby reducing UV absorption while maintaining reverse optical dispersion properties through alternative molecular arrangements
Solution Approach 2:
The patent employs simpler, more stable molecular structures that are less prone to oxidation and degradation, effectively replacing complex highly conjugated structures that suffer from poor thermal durability and yellowing
2Temperature
If HWP and QWP are combined to achieve reverse dispersion, then optical performance is improved, but process cost and device complexity increase
Solution Approach 1:
The patent merges the functions of HWP and QWP into a single polymerisable liquid crystal composition, eliminating the need for separate layers and lamination processes while achieving the desired reverse optical dispersion
Solution Approach 2:
The single liquid crystal composition performs multiple functions simultaneously - providing both the half-wave and quarter-wave retardation properties needed for reverse dispersion, thereby simplifying the overall device structure
3Temperature
If standard transparent materials are used, then positive optical dispersion is achieved, but anti-reflection performance deteriorates
Solution Approach 1:
The patent inverts the conventional approach by using polymerisable liquid crystal materials that can be induced to exhibit reverse optical dispersion through specific molecular structures and processing conditions, rather than accepting the positive dispersion of standard materials
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 provides polymer films with improved thermal properties, reduced yellowing, and lower production costs, suitable for mass production and effective anti-reflection in OLED displays.
Implementation Method 1
at least one of the chiral compounds comprises an photoisomerisable group
Implementation Method 2
polymerisable LC medium comprising one or more di- or multireactive mesogenic compounds
Implementation Method 3
optical retardation that matches exactly one quarter of the wavelength of the incident light
Data Source
AI summary
A polymerisable LC medium comprising one or more di- or multireactive mesogenic compounds, one or more chiral compounds with (s)-configuration, and one or more chiral compounds with (R)-configuration, wherein at least one of the chiral compounds comprises an photoisomerisable group. Further, a method for its preparation, a polymer film obtainable from a corresponding polymerisable LC medium, and a method of preparation of such polymer film. The polymer films may be used for purposes such as, for example, adjusting optical properties of a liquid crystal display (LCD), improving light utilization efficiency, ensuring anti-reflectivity and visibility in an organic light emitting device (OLED), or for AV/VR. Further, the use of such polymer film and said polymerisable LC medium for optical, electro-optical, decorative or security applications and for corresponding devices.