Variable Fresnel Lens with Phase Compensation for Wavelength Adaptability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Fresnel lenses and zone plates are fixed focal length elements, unable to adjust effectively for different wavelengths of light, leading to inefficiencies and multiple diffraction orders.
Innovation Solution
A variable-focus lens system comprising a variable wavefront component and a phase compensation component, using individually addressable transmissive electrodes and liquid crystal layers to dynamically adjust wavefront phases, eliminating phase discontinuities and wavelength dependency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional Fresnel lens or zone plate is used, then the structure is simple and manufacturing is easier, but the focal length is fixed and cannot be adjusted for different wavelengths
Solution Approach 1:
The patent applies the dynamics principle by making the focal length of the lens variable through electronic control. Liquid crystal layers are used as variable wavefront components that can be dynamically adjusted to change the focal length, allowing the lens to adapt to different wavelengths of light. This transforms a static optical element into a dynamic one that can be reconfigured electronically.
Solution Approach 2:
The patent implements parameter changes by modifying the refractive index of the liquid crystal material through applied electric fields. By changing the voltage applied to the liquid crystal layers, the optical parameters (focal length, wavefront phase) are dynamically adjusted to match different wavelengths, enabling wavelength adaptability without changing the physical structure.
2Productivity
If a conventional Fresnel zone plate is used, then manufacturing is simpler, but multiple diffractive orders are produced reducing efficiency
Solution Approach 1:
The patent applies local quality by introducing phase compensation zones with specifically tailored phase profiles in different regions of the lens. Each zone is designed with a unique phase delay pattern that compensates for the phase discontinuities causing multiple diffraction orders. This localized phase control ensures that light is directed primarily to the desired focal point, eliminating unwanted diffraction orders and improving optical efficiency.
Solution Approach 2:
The patent converts the harmful effect of phase discontinuities (which cause multiple diffraction orders) into a beneficial feature. By intentionally designing phase compensation components that introduce controlled phase delays, the system eliminates the harmful multiple orders while maintaining the simple Fresnel zone structure. The phase discontinuities are transformed from a defect into a controllable parameter that improves performance.
3Adaptability or versatility
If a variable-focus lens system with phase compensation is used, then wavelength adaptability and efficiency are improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single integrated optical system. The variable wavefront component and phase compensation component are combined in a unified lens structure, with both functions working together within the same optical path. This integration reduces the need for separate components and simplifies the overall system architecture despite the increased functional capabilities.
Solution Approach 2:
The patent implements multi-functionality by designing a single lens system that can perform multiple functions: focusing light at different focal lengths, adapting to various wavelengths, and compensating for phase discontinuities. The liquid crystal-based variable wavefront component serves multiple purposes simultaneously, reducing the need for multiple specialized components and managing the complexity through functional integration.
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 a variable focal length lens that functions correctly with any selected wavelength, minimizing diffraction orders and maximizing efficiency by ensuring in-phase wavefronts across all focal lengths.
Implementation Method 1
Holographic polymer-dispersed liquid crystal devices have been demonstrated in which applying an electric field across a holographically formed active layer can switch the device between a diffractive state and a non-diffractive state
Implementation Method 2
Holographic polymer-dispersed liquid crystal devices have been demonstrated in which applying an electric field across a holographically formed active layer can switch the device between a diffractive state and a non-diffractive state
Data Source
AI summary
An electrically variable lens comprising a variable Fresnel lens and a variable phase corrector plate. A liquid crystal variable Fresnel lens and liquid crystal phase corrector plate are varied in concert to compensate for wavefront discontinuities that would otherwise be produced by the Fresnel lens. The same principle is also used to provide a device capable of imposing an arbitrary spatial and temporal phase modulation on a wavefront.