Liquid Crystal Optical Element With Nanoimprint Alignment Control
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Solution Overview
Problem
Existing liquid crystal optical elements face challenges in aligning liquid crystal molecules accurately, leading to alignment defects which affect their optical properties and functionality.
Innovation Solution
A liquid crystal optical element is designed with a substrate and a first alignment control layer featuring projections at a predetermined pitch, formed using a crosslinkable liquid crystal polymer, which aligns and cures liquid crystal molecules in a specific direction, suppressing alignment defects through thermal or photo-nanoimprint methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid crystal polarization gratings are realized, then optical functionality is achieved, but alignment defects occur due to difficulty in aligning liquid crystal molecules in a predetermined direction
Solution Approach 1:
The alignment control layer is formed beforehand with projections that have specific surface treatments or orientations. These pre-formed structures guide the liquid crystal molecules to align in the desired direction during the subsequent liquid crystal layer formation process, eliminating alignment defects without requiring complex real-time alignment control
Solution Approach 2:
The alignment control layer acts as an intermediary between the substrate and the liquid crystal layer. It provides a controlled interface with projections that mediate the alignment process, transferring the predetermined orientation pattern to the liquid crystal molecules through surface interaction forces
2Manufacturing precision
If electric field alignment is used, then molecular alignment is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the electric field-based alignment mechanism with a structural/ geometric approach using projections in the alignment control layer. The physical structure of the projections creates surface forces that guide molecular alignment, eliminating the need for complex electric field generation systems and reducing device complexity
Solution Approach 2:
The alignment control layer with projections creates an self-aligning system where the liquid crystal molecules automatically orient themselves in the predetermined direction through interaction with the projection surfaces, without requiring external electric fields or complex alignment control mechanisms
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 effectively suppresses alignment defects in liquid crystal molecules, enabling stable and desired alignment patterns, even with complex configurations, and reduces manufacturing costs by simplifying the production process.
Implementation Method 1
curing the liquid crystal material in a state where liquid crystal molecules included in the liquid crystal material are aligned in a predetermined direction according to alignment restriction force of the first alignment control layer
Implementation Method 2
forming a first alignment control layer comprising projections arranged at a predetermined pitch by a thermal nanoimprint method or a photo-nanoimprint method
Implementation Method 3
forming a first alignment control layer comprising projections arranged at a predetermined pitch by a thermal nanoimprint method or a photo-nanoimprint method
Implementation Method 4
The liquid crystal polarization gratings are configured to change the propagation direction of light passing through their insides according to Bragg condition
Data Source
AI summary
According to one embodiment, a liquid crystal optical element includes a substrate, a first alignment control layer disposed on the substrate and comprising projections arranged at a predetermined pitch, and a first liquid crystal layer disposed on the first alignment control layer. The first liquid crystal layer comprises liquid crystal molecules which are aligned such that major axes of the liquid crystal molecules extend along the projections, respectively, and cured in a state where alignment directions of the liquid crystal molecules are fixed. The first alignment control layer is formed of a crosslinkable liquid crystal polymer.