Liquid-Crystal Selectable Bandpass Filter for Multispectral Sensing

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Solution Overview

Problem

Existing multispectral sensor devices face challenges in achieving rapid optical filter switching with minimal complexity and cost, particularly in switching between different wavelength ranges, often requiring multiple photodiodes and mechanical components.

Innovation Solution

The implementation of a liquid-crystal (LC) selectable bandpass filter, which includes an array of bandpass filters and an LC panel with matching aspect ratios, allows for electronic control of optical filter switching without moving parts, enabling the use of a single photodiode for multispectral data collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If mechanical components are used for optical filter switching, then filter switching can be achieved, but device complexity increases

Engineering Contradiction:

Improveoptical filter switching capabilityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical filter switching components with a liquid-crystal-based electronic system. The liquid-crystal panel with selectively controllable regions electronically switches between different bandpass filters without any moving parts, thereby achieving filter adaptability while reducing device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The liquid-crystal panel acts as an intermediary between the control system and the optical filter array. By controlling which LC regions transmit light, it selectively activates corresponding bandpass filters, enabling filter switching through an electronic mediator rather than direct mechanical actuation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple photodiodes are used for multispectral data collection, then spectral coverage is improved, but device complexity and cost increase

Engineering Contradiction:

Improvespectral resolutionVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes a single photodiode universal by combining it with a liquid-crystal-switchable filter array. The same photodiode can measure different spectral bands by electronically switching which bandpass filter is active, eliminating the need for multiple dedicated photodiodes while maintaining spectral resolution

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent adds the time dimension to spectral measurement. Instead of using multiple photodiodes simultaneously for different wavelengths, a single photodiode measures different wavelengths at different times by switching filters, transforming a spatial multiplexing problem into a temporal sequence

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If mechanical moving parts are used for filter switching, then filter selection is achievable, but reliability decreases

Engineering Contradiction:

Improvefilter switchingVSAvoidreliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent eliminates mechanical moving parts from the filter switching mechanism by using a liquid-crystal panel that changes optical properties through electrical control. This solid-state electronic switching replaces unreliable mechanical components, thereby improving reliability while maintaining filter switching capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables rapid optical filter switching, reduces device complexity and cost, and improves spectral resolution, while allowing for higher performance and flexibility in capturing multispectral data across various wavelength ranges.

Implementation Method 1

a liquid-crystal (LC) region included in a LC panel of the optical device... a LC region, of the array of LC regions, is to selectively transmit light that is incident on the LC region

Methodology Applied

Scientific EffectLiquid crystal optical switching: Liquid Crystals

Implementation Method 2

selectively transmitting, by a liquid-crystal (LC) region... light that is incident on the LC region

Methodology Applied

Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 3

a bandpass optical filter (herein referred to as a bandpass filter) transmits light in a particular range of wavelengths while absorbing light at wavelengths that fall outside of (i.e., above or below) the particular range of wavelengths

Methodology Applied

Scientific EffectOptical bandpass filtering: Filter (optical)

Data Source

PatentUS10962822B2Liquid-crystal selectable bandpass filter

Publication Date: 2021.03.30 VIAVI SOLUTIONS INC(US)

AI summary

An optical device may include an optical filter array comprising an array of bandpass filters, and a liquid-crystal (LC) panel comprising an array of LC regions. An aspect ratio of the LC panel may match an aspect ratio of the optical filter array such that each LC region, of the array of LC regions, is associated with a respective bandpass filter of the array of bandpass filters A LC region, of the array of LC regions, may selectively transmit light that is incident on the LC region.