Resonant LC Optical Cavity for Tight-Pitch Fast Pixel Switching
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Solution Overview
Problem
Existing liquid crystal (LC) devices face challenges in achieving high spatial resolution and fast switching speeds due to the requirement for thick LC layers, which leads to crosstalk and fringe fields at tight pixel pitches, especially in applications like wide-angle beam steering and holography.
Innovation Solution
The LC devices are designed with an optical cavity formed by a pair of reflectors to allow multiple passes of light, reducing the required LC layer thickness and enhancing phase shift, thereby minimizing fringe fields and switching time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional liquid crystal devices use high voltage and long duration to achieve sufficient light modulation, then light modulation effectiveness is improved, but power consumption increases and response time is excessive
Solution Approach 1:
The patent applies acoustic vibration to the liquid crystal layer to induce resonant motion of liquid crystal molecules. This mechanical vibration approach enables rapid reorientation of liquid crystal molecules without requiring high voltage, thereby reducing power consumption while achieving fast response times through resonant frequency excitation
Solution Approach 2:
The patent changes the physical state and response characteristics of liquid crystal molecules by applying acoustic energy at specific frequencies. This parameter change approach transforms the liquid crystal from a static, voltage-dependent state to a dynamic, vibration-responsive state, enabling fast switching with low power consumption
2Productivity
If acoustic energy is applied to liquid crystal molecules to induce resonant reorientation, then response time is reduced and power consumption is lowered, but device complexity increases due to additional acoustic transducer components
Solution Approach 1:
The patent integrates acoustic transducer functionality into existing device structures, allowing the same component to serve both acoustic actuation and potentially other functions. This multi-functionality approach reduces overall device complexity by eliminating the need for separate, dedicated acoustic actuation systems
Solution Approach 2:
The patent combines the acoustic transducer with existing device components, merging multiple functions into a single integrated structure. This consolidation reduces the number of discrete parts and simplifies the overall device architecture while maintaining the resonant liquid crystal switching functionality
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 configuration enables smaller pixel pitches and faster switching times, facilitating compact and efficient display applications such as head-mounted displays and configurable holograms.
Implementation Method 1
a resonant frequency of the liquid crystal molecules is determined and an acoustic transducer is coupled to the liquid crystal layer such that the acoustic transducer resonates the liquid crystal molecules at the resonant frequency
Implementation Method 2
acoustic energy is applied to the liquid crystal layer at the resonant frequency to reorient the liquid crystal molecules
Implementation Method 3
the aligned liquid crystal molecules modulate light passing through the device
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
A tunable liquid crystal (LC) device includes an LC layer between a pair of reflectors forming an optical cavity. The reflectors include conductive layers for applying an electrical signal to the LC layer. One of the conductive layers may include an array of conductive pixels for spatially selective control of the effective refractive index of the LC layer. The phase delay introduced by the LC layer may be greatly increased or magnified by placing the LC layer into the optical cavity. This enables a substantial reduction of the LC layer thickness, which in its turn enables very tight pitches of the LC pixels, with a reduced inter-pixel crosstalk caused by fringing electric fields, as well as faster switching times. A tight-pitch, fast LC device may be used as a configurable hologram or a spatial light modulator.