Polymer-Dispersed Liquid Crystal Grating Attenuator
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Solution Overview
Problem
Conventional polymer-dispersed liquid crystal gratings face challenges in achieving increasing diffraction efficiency in a specific direction without altering the liquid crystal box shape, leading to complex control and extended preparation periods.
Innovation Solution
A system and method involving a laser, beam expander, beam splitter prism, reflectors, and attenuators to modulate light intensity along a set curve, allowing the polymer-dispersed liquid crystal holographic grating to have varying diffraction efficiency without changing the liquid crystal box shape, using attenuators to control light intensity and interference fringes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of the grating is controlled to increase diffraction efficiency, then the diffraction efficiency increases, but the liquid crystal box shape must be altered which complicates control and extends preparation time
Solution Approach 1:
The patent applies local quality by introducing an attenuator that creates non-uniform light intensity distribution across the liquid crystal box. The attenuator has different transmittance at different positions, causing the polymer-dispersed liquid crystal to form with spatially varying diffraction efficiency while maintaining a uniform liquid crystal box shape. This resolves the contradiction by achieving variable diffraction efficiency through light intensity modulation rather than physical shape modification.
Solution Approach 2:
The patent changes the light intensity parameter along the optical path using an attenuator with position-dependent transmittance. By modulating the exposure light intensity rather than changing the liquid crystal box geometry, the diffraction efficiency is controlled through parameter adjustment. This simplifies the device structure and reduces preparation time while achieving the desired diffraction efficiency profile.
2Manufacturing precision
If the liquid crystal box shape is altered to achieve varying diffraction efficiency, then the diffraction efficiency varies as desired, but the preparation time increases and control becomes complex
Solution Approach 1:
The patent changes the light intensity parameter along the optical path using an attenuator with position-dependent transmittance. By modulating the exposure light intensity rather than changing the liquid crystal box geometry, the diffraction efficiency is controlled through parameter adjustment. This simplifies the device structure and reduces preparation time while achieving the desired diffraction efficiency profile.
Solution Approach 2:
The patent replaces the mechanical approach of altering liquid crystal box shape with an optical approach using an attenuator. Instead of physically modifying the container geometry, the system uses optical attenuation to achieve the same effect. This substitution reduces mechanical complexity and preparation time while maintaining precise control over diffraction efficiency distribution.
3Manufacturing precision
If conventional methods are used to control diffraction efficiency, then the grating can be formed, but the control process is complex and time-consuming
Solution Approach 1:
The patent introduces an attenuator as an intermediary component between the light source and the liquid crystal box. This attenuator simplifies the control process by providing a straightforward mechanism to modulate light intensity along the optical path. The attenuator acts as a mediator that translates desired diffraction efficiency profiles into corresponding light intensity distributions, making the control process easier and more intuitive.
Solution Approach 2:
The patent changes the light intensity parameter along the optical path using an attenuator with position-dependent transmittance. By modulating the exposure light intensity rather than changing the liquid crystal box geometry, the diffraction efficiency is controlled through parameter adjustment. This simplifies the device structure and reduces preparation time while achieving the desired diffraction efficiency profile.
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 large-scale preparation of polymer-dispersed liquid crystal gratings with diffraction efficiency increasing along the waveguide propagation direction, simplifying control and reducing preparation time by adjusting light intensity rather than exposure time.
Implementation Method 1
a laser for emitting a laser beam
Implementation Method 2
the first split light beam and the second split light beam form interference fringes
Implementation Method 3
a beam expander for expanding the laser beam
Implementation Method 4
a beam splitter prism for splitting the expanded laser beam into a first split light beam and a second split light beam
Implementation Method 5
a first reflector for reflecting the first split light beam to the liquid crystal box; a second reflector for reflecting the second split light beam to the liquid crystal box
Implementation Method 6
at least one attenuator arranged on an optical path between the beam expander and the liquid crystal box for gradually attenuating the laser light passing through the attenuator
Data Source
AI summary
A system includes a laser emitting a laser beam, a beam expander expanding the laser beam, a beam splitter prism splitting the expanded laser beam into first and second split light beams, a liquid crystal box containing polymer-dispersed liquid crystal, first and second reflectors reflecting the first and second split light beams to the liquid crystal box, respectively, and an attenuator arranged on an optical path between the beam expander and the liquid crystal box. The attenuator gradually attenuates at least one of the laser beam, the expanded laser beam, the first split light beam, or the second split light beam along a first set curve. The first split light beam and the second split light beam form interference fringes at the liquid crystal box to expose the polymer-dispersed liquid crystal to form a polymer-dispersed liquid crystal holographic grating having a diffraction efficiency decreasing along a second set curve.