Cholesteric Liquid Crystal Optical Element for Stimulus Detection
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Solution Overview
Problem
Existing optical elements using cholesteric liquid crystal layers primarily reflect light specularly and lack the ability to detect mechanical or other stimuli effectively.
Innovation Solution
A novel optical element with a cholesteric liquid crystal layer featuring a liquid crystal alignment pattern where the optical axis direction continuously rotates in-plane, incorporating a discontinuous portion with specific thickness and alignment, allowing for non-specular reflection and stimulus detection using a photodetector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a cholesteric liquid crystal layer is used for specular reflection, then light reflection efficiency is improved, but the ability to detect mechanical stimuli deteriorates
Solution Approach 1:
The cholesteric liquid crystal layer is divided into multiple regions with different liquid crystal alignment patterns. Some regions have patterns that enable specular reflection while other regions have patterns that enable non-specular reflection and stimulus detection. This segmentation allows the single layer to simultaneously perform both functions of light reflection and mechanical stimulus detection.
Solution Approach 2:
The cholesteric liquid crystal layer is designed to perform multiple functions: it provides specular reflection in certain regions, non-specular reflection in other regions, and mechanical stimulus detection through regions with specific alignment patterns. By incorporating multiple functional regions within a single layer, the structure achieves multi-functionality without requiring separate components.
2Adaptability or versatility
If a cholesteric liquid crystal layer with continuously rotating optical axis is used, then non-specular reflection capability is improved, but manufacturing complexity deteriorates
Solution Approach 1:
Different regions of the cholesteric liquid crystal layer are assigned different liquid crystal alignment patterns according to their specific functional requirements. Regions requiring specular reflection have one type of alignment pattern, while regions requiring non-specular reflection have continuously rotating optical axis patterns. This local quality approach allows each region to be optimized for its specific function while simplifying the overall design by not requiring complex patterns throughout the entire layer.
3Measurement precision
If the cholesteric liquid crystal layer is made thinner to improve discontinuous portion effect, then stimulus detection precision is improved, but light reflection efficiency deteriorates
Solution Approach 1:
Instead of uniformly reducing the thickness of the entire cholesteric liquid crystal layer, the invention introduces variation in the thickness of specific discontinuous portions within the layer. By controlling the thickness of these localized discontinuous regions rather than the overall layer thickness, the invention achieves improved stimulus detection precision while maintaining adequate light reflection efficiency through the remaining thicker regions.
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
Enables the detection of mechanical, optical, chemical, or electrical stimuli by varying the reflectivity in a selective wavelength range, enhancing the application range of cholesteric liquid crystal layers beyond traditional reflection capabilities.
Implementation Method 1
The cholesteric liquid crystal layer has wavelength selectivity in reflection and reflects only circularly polarized light in a specific twisted direction
Implementation Method 2
a cholesteric liquid crystal layer that is obtained by immobilizing a cholesteric liquid crystalline phase
Implementation Method 3
a photodetector that detects light reflected from the optical element
Data Source
AI summary
Provided are a novel optical element that can be used as a sensor or the like and a sensor including the same optical element. The optical element includes a cholesteric liquid crystal layer, in which the cholesteric liquid crystal layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from a liquid crystal compound changes while continuously rotating in at least one in-plane direction, and in a case where a cross-section taken in a thickness direction conforming the in-plane direction in which the direction of the optical axis rotates is observed using a scanning electron microscope, a portion where a bright line and a dark line derived from the cholesteric liquid crystalline phase are discontinuous is provided in the cholesteric liquid crystal layer in the in-plane direction in which the direction of the optical axis rotates.