Liquid Crystal Spatial Light Modulator Diffraction Grating Control
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Solution Overview
Problem
Conventional intensity modulation systems using liquid-crystal elements exhibit strong wavelength dependency, leading to reduced resolution in controlling output intensity across a wide optical band, as they require a wider voltage range to manage different wavelengths effectively.
Innovation Solution
A light control system employing a liquid-crystal type spatial light modulator functioning as a variable diffraction grating, with a controller adjusting the optical path by changing the shape of the diffraction grating to control light intensity with minimal wavelength dependency, allowing for high-resolution intensity modulation across a wide frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a liquid-crystal element is used to control light intensity by adjusting voltage, then the light intensity can be modulated, but the wavelength dependency becomes strong and resolution decreases when controlling over a wide optical band
Solution Approach 1:
The patent changes the control parameter from voltage (which has strong wavelength dependency) to the shape of the diffraction grating (which has minimal wavelength dependency). By controlling the spatial light modulator to function as a variable diffraction grating, the system achieves wavelength-independent light path control, resolving the contradiction between wide optical band adaptability and control resolution.
2Adaptability or versatility
If the voltage range is expanded to cover multiple wavelengths, then all wavelengths can be controlled, but the resolution for each individual wavelength decreases
Solution Approach 1:
The patent transitions from voltage control to diffraction grating shape control. The diffraction grating shape is controlled by phase modulation of the spatial light modulator, which has minimal wavelength dependency. This allows the system to maintain high resolution for each wavelength while simultaneously supporting a wide optical band, as the control parameter (grating shape) does not require expansion across wide voltage ranges.
3Reliability
If a diffraction grating shape is used to control light path, then wavelength dependency is reduced, but the system complexity increases
Solution Approach 1:
The patent makes the spatial light modulator perform multiple functions: it acts as both a phase modulator and a variable diffraction grating controller. By programming the phase pattern on the spatial light modulator, the system can dynamically create different diffraction grating shapes without requiring additional physical components, thereby achieving wavelength-independent control while maintaining relatively simple device architecture.
Solution Approach 2:
The patent replaces the conventional voltage-controlled liquid crystal system with a phase-controlled diffraction grating system. Instead of using voltage to directly control light intensity (which has wavelength dependency), the system uses phase modulation to create dynamic diffraction gratings that redirect light paths. This substitution eliminates the wavelength dependency issue while using the same physical hardware (spatial light modulator).
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 system achieves high-resolution control of output intensity with reduced wavelength dependency, enabling uniform modulation of light intensity for each wavelength component and flexible power spectrum adjustment, useful in various applications like optical communication and illumination systems.
Implementation Method 1
a spatial light modulator of a liquid-crystal type... by electrically controlling the spatial light modulator... by controlling a spatial distribution of a phase of the light incident on the spatial light modulator
Implementation Method 2
cause the spatial light modulator to function as a diffraction grating... change a path of a diffracted light from the spatial light modulator
Data Source
AI summary
A light control system is provided with a spatial light modulator of a liquid-crystal type, an input unit, and a controller. The input unit is configured to input a light to the spatial light modulator. The controller is configured to cause the spatial light modulator to function as a diffraction grating by electrically controlling the spatial light modulator. The controller is configured to change a path of a diffracted light from the spatial light modulator corresponding to the light input from the input unit by changing a shape of the diffraction grating.