Nematic-Cholesteric Liquid Crystal Optical Element for Phase Modulation
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Solution Overview
Problem
The existing optical modulators using liquid crystal layers have a relatively small amount of phase change for output light, limiting their effectiveness in modulating light based on the orientation changes of liquid crystal molecules.
Innovation Solution
An optical element comprising a nematic liquid crystal layer and a cholesteric liquid crystal layer, where the nematic layer changes the phase of light significantly by varying the orientation of its structural bodies, and the cholesteric layer reflects or transmits light while maintaining its polarization state, thereby enhancing the phase change of output light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single liquid crystal layer is used to modulate light, then the device structure remains simple, but the phase change amount is relatively small
Solution Approach 1:
The patent combines a nematic liquid crystal layer and a cholesteric liquid crystal layer into a single optical element. The nematic layer provides significant phase change (up to 4 times that of traditional single-layer systems), while the cholesteric layer maintains polarization state through selective reflection. This merging of two different liquid crystal types with complementary functions resolves the contradiction by achieving high phase change without proportionally increasing device complexity.
Solution Approach 2:
The optical element uses a composite structure with two distinct liquid crystal layers having different optical properties. The nematic layer (with birefringence properties) and cholesteric layer (with selective reflection properties) work together to produce enhanced phase modulation while maintaining polarization control, effectively using composite material principles to overcome the limitations of single-material systems.
2Power
If liquid crystal molecules are reoriented to modulate light, then light direction can be controlled, but the phase modulation efficiency remains low
Solution Approach 1:
By merging the nematic layer (responsible for high-efficiency phase modulation through molecular reorientation) with the cholesteric layer (which maintains polarization), the system achieves four times the phase change efficiency of traditional single-layer systems. This combination allows effective light modulation with smaller orientation changes required.
Solution Approach 2:
The patent changes the key parameter of phase modulation efficiency by introducing the nematic liquid crystal layer, which exhibits much higher phase change per unit orientation change compared to conventional single-layer systems. This parameter change directly addresses the low efficiency problem while the cholesteric layer ensures polarization maintenance.
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 optical element achieves a substantial increase in phase change of output light, allowing for more effective modulation of light waves, with the phase change rate being four times that of traditional systems, facilitating efficient light manipulation and potential applications in beam splitters or optical isolators.
Implementation Method 1
the nematic layer changes the phase of light significantly by varying the orientation of its structural bodies
Implementation Method 2
the cholesteric layer reflects or transmits light while maintaining its polarization state
Data Source
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AI summary
An optical element 1 includes a first layer (A1) and a second layer (A2) that faces the first layer (A1). The first layer (A1) includes a plurality of first structural bodies (B1) that each have optical anisotropy. In reflection of light entering from the first layer (A1), the second layer (A2) reflects the light while maintaining a polarization state of the light at incidence and at the reflection. The first layer (A1) changes, according to directions of orientation of the first structural bodies (B1), a phase of the light from a phase at incidence to the first layer (A1) from outside of the first layer (A1) to a phase at output from the first layer (A1) toward the second layer (A2). The first layer (A1) changes the phase of the light from a phase at incidence to the first layer (A1) from the second layer (A2) to a phase at output from the first layer (A1) toward the outside of the first layer (A1) according to the directions of orientation of the first structural bodies (B1).