Liquid Crystal Plasmonic Color Device
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Solution Overview
Problem
Plasmonic structures with static optical characteristics limit their applications, as they cannot be dynamically tuned for practical color generation across the visible spectrum, especially in the visible regime, where existing methods only achieve modest shifts in plasmon resonance, restricting their use in display technologies.
Innovation Solution
A liquid crystal (LC)-plasmonic system is developed, where high birefringent liquid crystals change the local dielectric constant of nanostructured plasmonic materials, enabling continuous tuning of plasmonic resonance over 95 nm or more by varying the voltage, allowing for dynamic color generation across the entire visible spectrum with millisecond-scale response times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pigmentation-based color filtering is used, then color generation is achieved, but resolution and efficiency are limited
Solution Approach 1:
The patent changes the fundamental parameter from pigmentation-based color filtering to plasmonic resonance-based color generation. By adjusting the dimensions, shape, and material composition of metallic nanostructures, the plasmon resonance frequency can be tuned across the visible spectrum, enabling high-resolution color generation without conventional color filters
Solution Approach 2:
The patent replaces the mechanical/optical system of conventional color filters with a field-based plasmonic system. The color generation is achieved through electromagnetic field interactions with metallic nanostructures, eliminating the need for physical color filter layers and enabling thinner, higher-resolution displays
2Adaptability or versatility
If plasmonic structures are fabricated with fixed dimensions, then manufacturing is simplified, but optical characteristics remain static and cannot be tuned
Solution Approach 1:
The patent introduces dynamic control mechanisms to adjust plasmonic resonance in real-time. This includes using liquid crystals to modify the local dielectric environment, employing phase-change materials to alter nanostructure geometry, and using electro-optic or magneto-optic materials to dynamically tune resonance frequency, enabling full-color display capabilities
Solution Approach 2:
The patent combines plasmonic materials with functional materials such as liquid crystals, phase-change materials, and electro-optic materials to create composite structures. These composites enable dynamic tuning of plasmon resonance by leveraging the unique properties of each material, achieving both color versatility and dynamic controllability
3Adaptability or versatility
If liquid crystals are used to shift plasmon resonance, then color tunability is achieved, but the tuning range is limited to approximately 10-40 nm in the visible regime
Solution Approach 1:
The patent applies local quality by creating heterogeneous plasmonic structures with different geometries, materials, and orientations within the same device. By spatially varying the nanostructure properties, the device can access a broader range of plasmon resonance frequencies, extending the tunable range beyond what uniform liquid crystal systems can achieve
Solution Approach 2:
The patent designs multi-functional plasmonic structures that can operate across different spectral ranges and respond to multiple control mechanisms. The system can simultaneously achieve broad spectral coverage through geometric tuning while maintaining dynamic control through liquid crystals or other active materials, creating a universal platform for full-color display
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
This approach enables the generation of a full range of visible colors with reduced subpixels, improving resolution by 33% and achieving the largest plasmonic tuning range through LCs, making plasmonic structures more suitable for display and filter technologies with fast color switching capabilities.
Implementation Method 1
high birefringent liquid crystals change the local dielectric constant of nanostructured plasmonic materials
Implementation Method 2
liquid crystals (LC) are shown to impart full visible spectrum tunability to nanostructured plasmonic materials by changing the nanostructure's local dielectric constant
Implementation Method 3
Plasmonic materials are defined as those utilizing surface plasmons, which exist at metal-dielectric interfaces. Light coupled to these collective electron oscillations is absorbed, leading to subtractive color generation
Implementation Method 4
a cell is made to contain and align (so as not to scatter light) an LC with the ability to realign the LC with an electric field
Implementation Method 5
change the dielectric constant surrounding the metallic nanostructure, thereby shifting the plasmon resonance spectral location
Data Source
AI summary
Color derived from metallic nanostructures are often more efficient, more robust to environmental changes, and near impossible to damage or bleach due to overexposure. The embodiments combine these advantages with the millisecond re-configurability of liquid crystals to actively control a reflective color of a metallic nanostructure. Of the current technologies that boast active color tunability, many are pigmentation based (e-ink in e-readers) and/or need seconds to change color (photonic ink, electrochromic materials). Speed is an advantage of the embodiments and is comparable to current liquid crystal displays (˜120 Hz). Traditional LC displays use static polymer films (color filters) and white back light to generate color. Being able to actively tune the color from a single metallic nanostructure allows for smaller pixel size, increased resolution, and decreased fabrication cost compared to a conventional RGB color pixel without needing external white light source for extremely low power operations.