Dynamic Polarizer for Broadband Imaging
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Solution Overview
Problem
Conventional polarizing grids in imaging systems are inefficient for broadband imaging as they discard unpolarized light, requiring mechanical adjustments that are slow and complex, and are incompatible with dynamically variable sub-pixel approaches.
Innovation Solution
A dynamic polarizer with patterned layers of materials like vanadium dioxide or electrochromic polymers that can reversibly transition between polarizing and non-polarizing states in response to an electromagnetic stimulus, allowing for on-demand polarization and broadband imaging without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional polarizing filter is used in front of the imaging detector, then polarized light can be measured, but broadband unpolarized light is discarded and quantum efficiency is reduced
Solution Approach 1:
The patent employs a dynamic polarizer made of liquid crystal material that can be switched between polarizing and non-polarizing states through application of voltage. This allows the system to dynamically adapt its polarization filtering capability, enabling polarization measurements only when needed while allowing full broadband light transmission during non-polarization imaging, thus resolving the contradiction between measurement precision and energy loss
Solution Approach 2:
The polarizer's optical properties are changed by applying an electrical stimulus that alters the liquid crystal material's molecular orientation. When voltage is applied, the liquid crystal molecules reorient to allow broadband light transmission; when voltage is removed, they return to a state that polarizes light. This parameter change enables the system to switch between measurement and imaging modes, eliminating the trade-off between polarization capability and quantum efficiency
2Adaptability or versatility
If a mechanical filter wheel is used to rotate or remove polarizing filters, then polarization measurements can be performed, but the system becomes slow and mechanically complex
Solution Approach 1:
The patent replaces the mechanical filter wheel system with an electrically controlled liquid crystal polarizer. Instead of physically rotating or removing filters using motors and mechanical components, the system uses electrical voltage to switch the polarizer's state. This substitution eliminates moving parts, reduces mechanical complexity, and enables rapid switching between polarization and non-polarization modes, resolving the contradiction between adaptability and device complexity
3Measurement precision
If a polarizing grid is always positioned in front of the imaging detector, then polarization can be measured continuously, but broadband imaging capability is lost
Solution Approach 1:
The liquid crystal polarizer provides dynamic control over its polarization function, allowing the system to switch between polarization measurement mode and broadband imaging mode as needed. This temporal separation of functions enables the same optical path to serve both purposes, resolving the contradiction between continuous polarization measurement capability and broadband imaging capability
Solution Approach 2:
The single liquid crystal polarizer component serves multiple functions: it acts as a polarizing filter for polarization measurements when voltage is removed, and as a transparent broadband window for imaging when voltage is applied. This multi-functionality eliminates the need for separate optical paths or components for polarization and imaging, resolving the contradiction between measurement precision and adaptability
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 rapid reconfiguration of polarization on a frame-by-frame basis, maintaining high quantum efficiency and allowing dynamic polarization in specific regions while performing broad-band imaging, thus overcoming the inefficiencies of conventional systems.
Implementation Method 1
the material being operable to alter its electrical conductivity responsive to an applied electromagnetic stimulus to reversibly transition between a polarizing state and a non-polarizing state
Implementation Method 2
the material is substantially transparent to infrared light in the non-polarizing state, and is substantially opaque to infrared light in the polarizing state
Data Source
Figure 1~2
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AI summary
A dynamically controllable polarizer integrated with an imaging detector to provide "on demand" variable polarization measurements. In one example, an imaging system includes a detector array including a plurality of pixels arranged in a two-dimensional array, and a dynamic polarizer coupled to the detector array, the dynamic polarizer including at least one patterned layer of a material disposed on the detector array, the material being operable to alter its conductivity responsive to an applied stimulus to reversibly transition between a polarizing state and a non-polarizing state.