Electro-Optic Zoom Lens Using Liquid Crystal Polarization Control
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Solution Overview
Problem
Conventional mechanical zoom systems in imaging systems face challenges such as space and power consumption, weight, slow operation, interference with infrared detection, and inability to operate across broad temperature and spectral ranges, as well as issues with optical aberrations and reticle visibility in all zoom states.
Innovation Solution
An electro-optically switched zoom lens system using a polarizing controller, liquid crystal polarization rotator, birefringent compensating lenses, and tunable polarization filters to achieve fast zooming, broad spectral and thermal range operation, and in-focus reticle visibility across all zoom states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical zoom system is used to adjust focal length, then zoom capability is achieved, but space consumption increases due to motors, gears, and lens movement space
Solution Approach 1:
The patent replaces the mechanical zoom system with an electro-optical system using liquid crystal lenses. The liquid crystal lenses change focal length by applying voltage to alter the refractive index, eliminating the need for mechanical motors, gears, and physical lens movement. This substitution directly resolves the space consumption issue while maintaining zoom capability.
Solution Approach 2:
The patent utilizes voltage-controlled refractive index changes in liquid crystal materials to achieve focal length adjustment. By changing the electrical parameter (voltage), the optical parameter (refractive index) changes, which in turn changes the focal length. This parameter transformation eliminates mechanical components and reduces space requirements.
2Adaptability or versatility
If a mechanical zoom system is used to adjust focal length, then zoom capability is achieved, but weight increases due to motors, gears, and power supply
Solution Approach 1:
The patent replaces heavy mechanical components (motors, gears, power supply) with lightweight electro-optical components. The liquid crystal lenses require only minimal electrical power to change focal length, eliminating the need for heavy mechanical drive systems and associated power supplies, thereby significantly reducing overall system weight.
3Adaptability or versatility
If a mechanical zoom system is used to adjust focal length, then zoom capability is achieved, but operation speed decreases due to physical movement time
Solution Approach 1:
The patent replaces slow mechanical lens movement with rapid electro-optical switching. Liquid crystal lenses can change focal length almost instantaneously by applying voltage, eliminating the time required for mechanical movement. This enables fast zoom operation suitable for applications like UAVs and riflescopes where rapid response is critical.
4Adaptability or versatility
If a mechanical zoom system is used, then zoom capability is achieved, but infrared detection is interfered with due to heat radiation from motors and gears
Solution Approach 1:
The patent replaces heat-generating mechanical components with electro-optical liquid crystal lenses. Liquid crystals require minimal power and generate negligible heat, eliminating the thermal radiation that interferes with infrared detection. This enables the system to be used in infrared imaging applications without thermal contamination.
5Speed
If birefringent lenses are used to achieve fast switching, then operation speed is improved, but optical aberrations increase due to varying refractive index
Solution Approach 1:
The patent employs multiple liquid crystal lens elements with different orientations and properties arranged in a specific configuration. Each lens element addresses specific aberration types, and their combined effect produces an aberration-free image. This local optimization of each lens element's function resolves the aberration issue while maintaining fast switching capability.
Solution Approach 2:
The patent uses composite liquid crystal lens systems combining different liquid crystal materials with complementary properties. By combining materials with opposite or complementary birefringence characteristics, the system achieves fast switching while canceling out optical aberrations through the composite structure.
6Adaptability or versatility
If mechanical zoom systems are used, then zoom capability is achieved, but reliability decreases due to part wear and maintenance requirements
Solution Approach 1:
The patent replaces mechanical components subject to wear (motors, gears, moving parts) with solid-state liquid crystal lenses. Liquid crystal lenses have no moving parts and no wear mechanisms, providing indefinite operational life without maintenance. This dramatically improves reliability and eliminates downtime associated with mechanical system repairs.
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 solution enables fast, efficient, and aberration-corrected zooming with instant state switching, suitable for applications like UAVs and riflescopes, while maintaining image quality and reducing operational costs and downtime.
Implementation Method 1
A liquid crystal polarization rotator transmits and rotates the polarization state of light it transmits by a selected amount when activated
Implementation Method 2
electro-optically switched zoom lens system
Implementation Method 3
birefringent lenses, on the other hand, produce a new aberration type, herein referred to as 'birefringent aberration,' because the crystal material out of which they are made results in an extra-ordinary refractive index that varies with a ray's propagation angle through the lens
Implementation Method 4
A polarizing controller transmits light of a selected polarization state to a zoom lens system
Data Source
AI summary
A fast, electro-optically switched zoom lens system operates across a broad spectral and thermal range while correcting for birefringent aberrations by means of a polarizing system that preferably includes polarizing reticles.