Liquid Crystal Element with Uneven Diffractive Surface
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Solution Overview
Problem
Current liquid crystal devices for 3D displays and optical systems lack the ability to efficiently switch between diffraction and transmissive states, limiting their versatility and light distribution capabilities for applications like 3D mapping.
Innovation Solution
A liquid crystal element with a diffractive optical element layer having an uneven surface and a liquid crystal material that can change refractive index in response to electric fields, allowing the device to switch between diffraction and transmissive states, and a projection device using two such elements to provide different diffraction patterns for improved 3D mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a liquid crystal device uses a conventional flat surface structure, then the device structure is simple, but the device cannot efficiently switch between diffraction and transmissive states
Solution Approach 1:
The patent applies curvature by introducing an uneven surface structure on the diffractive optical element layer, replacing the conventional flat surface. This uneven surface includes protrusions and recesses that create phase differences in transmitted light, enabling diffraction functionality. The curved/uneven surface allows the liquid crystal device to switch between diffraction and transmissive states by controlling the liquid crystal orientation, thereby resolving the contradiction between versatility and structural simplicity.
2Adaptability or versatility
If a liquid crystal device uses a single diffractive pattern, then the device structure is simple, but the device lacks versatility for different 3D mapping applications
Solution Approach 1:
The patent applies dynamics by making the diffractive pattern switchable rather than fixed. The liquid crystal layer can be electrically controlled to change its orientation state, thereby dynamically switching between different diffraction patterns (e.g., different pitch values). This dynamic capability allows a single device structure to provide multiple diffraction patterns for different 3D mapping applications, resolving the contradiction between pattern variety and structural simplicity.
3Illumination intensity
If the refractive index difference between liquid crystal material and diffractive optical element layer is large, then the diffraction effect is strong, but the transmissive state efficiency is reduced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive index difference between the liquid crystal material and the diffractive optical element layer. By optimizing this refractive index difference to be within a specific range (0.05 to 0.20), the device achieves both strong diffraction effect when needed and efficient transmissive state when the liquid crystal is in the aligned state. This parameter optimization resolves the contradiction between diffraction efficiency and transmissive capability.
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 generation of multiple diffraction patterns along the same axis, enhancing 3D mapping applications and allowing the projection device to switch between states for optimal light distribution, improving both the versatility and effectiveness of the device.
Implementation Method 1
liquid crystal devices play an important role in many optical systems by means of the change in the phase or the polarization state of light
Implementation Method 2
The liquid crystal material has a first effective refractive index at a first operating state of the liquid crystal element
Implementation Method 3
Liquid crystal devices may serve as an optical diffraction element which may diffract light by several angles, thereby generating a diffraction pattern of light
Data Source
AI summary
A liquid crystal element includes a substrate, a diffractive optical element layer, and a liquid crystal material. The diffractive optical element layer has an uneven surface. The liquid crystal material is between the substrate and the uneven surface of the diffractive optical element layer. The liquid crystal material is disposed contiguously with the uneven surface of the diffractive optical element layer.