Layered Twisted Liquid Crystal Hyperspectral Filter
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Solution Overview
Problem
Current spectral filters, such as Linescan, acousto-optic tunable, and Lyot filters, face limitations in wavelength analysis due to fixed detectable wavelengths per pixel, physical size constraints, and high manufacturing costs, hindering the development of high-resolution and miniaturized image sensors.
Innovation Solution
A transmissive wavelength tunable hyperspectral filter using layered twisted liquid crystal thin films, which selectively adjusts transmissive wavelengths through external stimuli like electric fields, temperature, moisture, or light, allowing for broadband reflection bandgap shifting and precise wavelength control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional spectral filters (Linescan, acousto-optic, Lyot) are used, then wavelength separation function is achieved, but physical size increases and manufacturing complexity increases
Solution Approach 1:
The patent changes the physical-chemical parameters of the liquid crystal material by introducing a chiral dopant to induce helical twisting, transforming the conventional planar liquid crystal structure into a twisted helical structure. This parameter change enables the filter to achieve wavelength tuning functionality while reducing physical size and manufacturing complexity compared to conventional filters.
Solution Approach 2:
The patent uses a composite liquid crystal system consisting of host liquid crystal molecules and chiral dopant molecules. The chiral dopant (e.g., R- or S-8-chloro-5-methyl-1-undecanol) interacts with the host liquid crystal to form a twisted helical structure with controllable pitch, creating a composite material that achieves both size reduction and wavelength selectivity.
2Productivity
If fixed optical filters are used, then manufacturing is simpler, but data processing speed decreases due to analyzing unnecessary wavelengths
Solution Approach 1:
The patent implements a dynamic optical filter using liquid crystal that can change its transmission characteristics in real-time. By applying external stimuli (electric field, temperature, light), the helical pitch and thus the transmitted wavelength can be dynamically adjusted, enabling the system to focus only on necessary wavelengths and improve data processing speed while maintaining manufacturing simplicity.
Solution Approach 2:
The patent enables parameter changes in the optical filter by utilizing the responsiveness of liquid crystal to external stimuli. The transmission wavelength can be tuned by changing temperature, applying electric fields, or exposing to light, allowing the filter to adapt to different measurement requirements and process only relevant spectral data, thereby improving productivity.
3Measurement precision
If high-resolution image sensors are implemented with fixed transmission wavelength per pixel, then spectral analysis capability is improved, but physical size of elements increases
Solution Approach 1:
The patent makes each pixel element universal by implementing a tunable wavelength filter that can analyze multiple wavelengths sequentially. Instead of requiring separate fixed-wavelength filters for each wavelength, a single pixel with the liquid crystal filter can tune across the spectral range, achieving high spectral analysis capability while reducing the physical size of each element.
Solution Approach 2:
The patent enables dynamic wavelength tuning at each pixel element, allowing the same physical component to serve multiple spectral analysis functions. By dynamically adjusting the liquid crystal's helical pitch, each pixel can sequentially measure different wavelengths, achieving high measurement precision without increasing the physical size of the sensor elements.
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 efficient separation of wavelengths with reduced physical size and manufacturing complexity, enhancing data processing speed and image sensor performance by allowing for a narrower full width at half maximum (FWHM) and higher transmittance.
Implementation Method 1
the layered twisted liquid crystal thin film selectively reflects, among the incident lights, only light of a specific wavelength region through Bragg reflection
Implementation Method 2
An acousto-optic tunable filter is a tunable filter that may selectively transmit light of various wavelengths with one filter by changing a refractive index of a crystal through an acoustic wave generated by a piezoelectric transducer
Implementation Method 3
A Lyot filter is a filter that selectively passes only light of a desired wavelength by laminating birefringent optical filters that pass light of a specific wavelength
Data Source
AI summary
Disclosed is a transmissive wavelength tunable hyperspectral filter using layered twisted liquid crystal thin film, wherein the transmissive wavelength tunable hyperspectral filter is formed by laminating two or more layered twisted liquid crystal thin films having different broadband reflection bandgaps, wherein each of the layered twisted liquid crystal thin films includes a twisted liquid crystal layer including a plurality of unit liquid crystal molecules, and formed by arranging twisted liquid crystal complexes defining a preset cone angle along the helical axis with respect to the helical axis, and includes a pseudo-layer formed by arranging a plurality of twisted liquid crystal layers in a lengthwise direction of the helical axis at a preset inter-layer pitch (P).