Light Sensor Pixels Using Fano Filters for Narrowband Spectral Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light sensors for spectral analysis face limitations in effectively filtering and analyzing light across multiple wavelength ranges, particularly due to the complexity and cost of manufacturing multilayer interferometric filters and the low spectral selectivity of plasmonic filters.
Innovation Solution
A light sensor design incorporating pixels with Fano resonance filters, where one pixel has a band-cut Fano resonance filter and another lacks it, utilizing a periodic structure in a dielectric material stack to achieve selective light rejection and analysis across narrow wavelength ranges, allowing for precise spectral analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multilayer interferometric filters are used for spectral analysis, then spectral selectivity is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the fundamental operating parameter from interferometric resonance (requiring multiple precise layers) to Fano resonance in a single dielectric layer with periodic structure. This parameter change enables achieving narrow bandwidth spectral selectivity with a simpler single-layer structure, directly resolving the contradiction between spectral precision and manufacturing complexity
Solution Approach 2:
The patent uses composite dielectric materials with specific refractive indices (first dielectric material with refractive index n1, second dielectric material with refractive index n2) to achieve the desired Fano resonance characteristics. This composite approach provides spectral selectivity comparable to multilayer interferometric filters while using a simpler single-layer periodic structure
2Device complexity
If plasmonic resonance metallic filters are used, then device complexity is reduced, but spectral selectivity deteriorates
Solution Approach 1:
The patent changes the material parameter from metallic (plasmonic) to dielectric, and changes the resonance mechanism parameter from plasmonic resonance to Fano resonance. This dual parameter change maintains the structural simplicity of single-layer filters while dramatically improving spectral selectivity, achieving narrow bandwidth filtering (Q-factor > 10) that was not achievable with plasmonic filters
Solution Approach 2:
The patent substitutes the plasmonic resonance mechanism (based on free electron oscillation in metals) with Fano resonance mechanism (based on interference between discrete and continuous states in dielectric periodic structures). This substitution replaces a mechanism with poor spectral selectivity with one that provides narrow bandwidth filtering while maintaining structural simplicity
3Measurement precision
If Fano resonance filters with periodic structure are used, then spectral selectivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the structural parameter from requiring sub-wavelength precision (as in photonic crystals) to a more relaxed periodic structure where the period can be a significant fraction of the wavelength. This parameter change maintains narrow bandwidth spectral selectivity while reducing manufacturing precision requirements to standard semiconductor fabrication capabilities
Solution Approach 2:
The patent applies the periodic structure only in the region where Fano resonance is needed, while other regions of the dielectric layer can have different properties. This local application of periodic structure allows optimization of spectral selectivity in specific wavelength ranges without requiring precision throughout the entire filter structure
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 efficient and cost-effective spectral analysis of light over multiple wavelength ranges with improved spectral selectivity, reducing manufacturing complexity and operational costs compared to traditional filter technologies.
Implementation Method 1
Each filter comprises a periodic structure defined in a first layer of a first dielectric material
Implementation Method 2
Said first filter comprises a periodic structure defined in a first layer of a first dielectric material
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present description relates to a light sensor (1) comprising pixels (Pix1, Pix2) each having a photoconversion area (PD1, PD2), in which a first (Pix2) of said pixels includes a first Fano resonance filter (F2) and a second of said pixels (Pix1) is without a Fano resonance filter.