Electro-Optical 2D Imaging Spectrometer Using Interconnected LC Fabry-Pérot Filters

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current imaging spectrometers are costly and time-consuming to manufacture, sensitive to input irradiance variations, and suffer from cross-talk/straylight due to conventional optical elements, necessitating optimization for reduced manufacturing time and cost.

Innovation Solution

A light transmission path utilizing interconnected liquid crystal Fabry-Pérot filter elements with tunable bandpass characteristics, configured to shift frequency responses based on applied voltages, eliminating the need for homogenizers and conventional optics, and forming a 2D imaging spectrometer with fiber bundles that replace the spectrometer slit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional imaging spectrometers with expensive optics and homogenizers are used, then spectral measurement accuracy is improved, but manufacturing cost and manufacturing time increase

Engineering Contradiction:
Improvespectral measurement accuracyVSAvoidmanufacturing cost and time
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts and removes the expensive conventional optics (lenses, mirrors) and homogenizers from the spectrometer system, replacing them with liquid crystal Fabry-Pérot filter elements that perform both wavelength selection and light distribution functions, thereby reducing manufacturing cost and time while maintaining spectral measurement accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The liquid crystal Fabry-Pérot filter elements serve multiple functions simultaneously: they act as wavelength-selective filters, light distributors across the detector array, and spectral dispersion elements, eliminating the need for separate conventional optical components and reducing overall system complexity and manufacturing burden

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of information

If conventional optical elements are used in imaging spectrometers, then spectral information can be obtained, but cross-talk/straylight between different spatial intensity samples occurs

Engineering Contradiction:
Improvespectral information acquisitionVSAvoidcross-talk/straylight
Core Design Contradiction:
Loss of informationVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the mechanical/optical system of conventional lenses and mirrors with an electro-optical system using liquid crystal Fabry-Pérot filter elements that use electrical voltage control to achieve wavelength selection and light routing, eliminating the physical pathways that cause cross-talk and straylight in conventional systems

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The liquid crystal Fabry-Pérot filter elements dynamically adjust their optical properties through voltage control, allowing precise wavelength selection and light distribution without the fixed physical constraints of conventional optics, thereby eliminating cross-talk and straylight while maintaining spectral information acquisition

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If imaging spectrometers use conventional optics with multiple alignment steps, then spectral resolution is achieved, but alignment time and integration complexity increase

Engineering Contradiction:
Improvespectral resolutionVSAvoidalignment time and integration complexity
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the wavelength selection, light dispersion, and detection functions into a single integrated liquid crystal Fabry-Pérot filter element system, eliminating the need for multiple separate optical components and their associated alignment steps, thereby reducing integration complexity and time while maintaining spectral resolution

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The liquid crystal Fabry-Pérot filter elements achieve spectral resolution through electrical parameter changes (voltage control of liquid crystal refractive index) rather than mechanical alignment, allowing rapid tuning and elimination of time-consuming alignment procedures while maintaining precise spectral discrimination

Inventive Principle:
Principle #35Parameter changes

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

This solution reduces manufacturing time and cost, eliminates cross-talk, and enables quick spectral tuning, achieving 2D imaging with spectral information without conventional optics, while maintaining high spectral resolution and flexibility.

Implementation Method 1

The first and second liquid crystal Fabry-Pérot filter elements are interconnected and configured to shift the first and second bandpass filter characteristics to each other to form a common bandpass filter characteristic of the light transmission path according to a difference between the first and second voltages

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 2

liquid crystal Fabry-Pérot filter element has a first bandpass filter characteristic for light being polarized in a predetermined direction

Methodology Applied
Scientific EffectFabry-Pérot interference: Fabry-Perot Interferometer

Implementation Method 3

A refraction index of the liquid crystal inside the cavity may vary corresponding to the first/second voltage applied at the respective liquid crystal Fabry-Pérot filter element

Methodology Applied
Scientific EffectLiquid crystal phase transition: Liquid Crystals

Data Source

PatentEP3760989B1Electro-optical 2d imaging spectrometer
Publication Date: 2023.12.20 AIRBUS DEFENCE & SPACE GMBH
  • EP3760989B1 patent drawingFigure 1
  • EP3760989B1 patent drawingFigure 2
  • EP3760989B1 patent drawingFigure 3

AI summary

A light transmission path for a spectrometer is provided. The light transmission path comprises a first liquid crystal Fabry-Perot filter element. The first liquid crystal Fabry-Perot filter element has a first bandpass filter characteristic for light being polarized in a predetermined direction. The first bandpass filter characteristic is based on a first voltage applied at the first liquid crystal Fabry-Pérot filter element. The light transmission path comprises a second liquid crystal Fabry-Perot filter element. The second liquid crystal Fabry-Perot filter element has a second bandpass filter characteristic for light being polarized in the predetermined direction. The second bandpass filter characteristic is based on a second voltage applied at the second liquid crystal Fabry-Pérot filter element. The first and second liquid crystal Fabry-Perot filter elements are interconnected and configured to shift the first and second bandpass filter characteristics to each other to form a common bandpass filter characteristic of the light transmission path according to a difference between the first and second voltages. Further, a plurality of such light transmission paths and a spectrometer with the plurality of such light transmission paths are provided