Solid-State Hyperspectral Focal Plane Array Eliminates Mechanical Scanners

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Solution Overview

Problem

Conventional spectroscopy and hyperspectral imaging systems are bulky, complex, and prone to noise due to mechanical setups, requiring scanners and diffraction gratings, and involve costly post-processing for image reconstruction.

Innovation Solution

A solid-state focal plane array using individually tuned photodiodes with resonant cavity enhanced photodetection, arranged in a two-dimensional array to provide spectral information on a pixel-by-pixel basis, allowing for hyperspectral imaging at video frame rates without the need for scanners or diffraction gratings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional spectroscopy systems use scanners and diffraction gratings, then spectral analysis capability is achieved, but system complexity and bulk increase

Engineering Contradiction:

Improvespectral analysis capabilityVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical scanning systems and diffraction gratings with a solid-state focal plane array consisting of multiple photodiodes. Each photodiode is tuned to detect specific wavelengths through resonant cavity enhancement, eliminating the need for moving mechanical parts while maintaining spectral analysis capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system divides the spectral detection function into multiple independent photodiodes, each responsible for detecting a specific wavelength range. This segmentation allows parallel detection of multiple wavelengths simultaneously, replacing the sequential scanning approach with a compact array architecture.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If mechanical scanning systems are used, then spectral data acquisition is possible, but susceptibility to vibrations and shock increases

Engineering Contradiction:

Improvespectral data acquisitionVSAvoidsusceptibility to vibrations and shock

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The invention eliminates mechanical scanning components by using a solid-state photodiode array that performs spectral detection through electronic means. The resonant cavity-enhanced photodiodes are stationary and have no moving parts, making the system inherently resistant to vibrations and shock while maintaining spectral data acquisition capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Loss of information

If conventional systems require post-processing for image reconstruction, then spectral information can be obtained, but processing time and cost increase

Engineering Contradiction:

Improvespectral information retrievalVSAvoidprocessing time

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The system performs wavelength-specific detection in advance by tuning each photodiode to specific wavelengths before data acquisition. The resonant cavities are pre-configured to resonate at desired wavelengths, enabling direct detection without requiring complex post-processing or image reconstruction algorithms.

Inventive Principle:

Principle #10Preliminary action

4Device complexity

If solid state focal plane array with individually tuned photodiodes is used, then system complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvesystem complexityVSAvoidphotodiode tuning precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent achieves wavelength selectivity by changing the physical parameters of the resonant cavities, specifically the thickness and refractive index of dielectric layers. By precisely controlling these parameters during fabrication, each photodiode can be tuned to detect specific wavelengths, simplifying the overall system while requiring high manufacturing precision for the cavity structures.

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

Enables efficient materials identification through spectral signature analysis, reducing system complexity and cost, while providing robustness against environmental vibrations and noise, and enabling real-time spectral data acquisition.

Implementation Method 1

at least one of the photodiodes is configured as a resonant cavity enhanced photodetector

Methodology Applied

Scientific EffectResonant cavity enhancement: Resonance

Implementation Method 2

one or more of the photodiodes in an array comprise a semiconductor or dielectric distributed Bragg reflector

Methodology Applied

Scientific EffectDistributed Bragg reflection: Bragg Diffraction

Implementation Method 3

a photodiode array, wherein at least one of the photodiodes is configured as a resonant cavity enhanced photodetector

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS8247754B2Solid state focal plane array for hyperspectral imaging applications

Publication Date: 2012.08.21 LG INNOTEK CO LTD

AI summary

A focal plane array suitable for use in hyperspectral imaging applications is provided. The focal plane array comprises pixels comprising arrays of photodiodes, wherein each photodiode in each array is selectively sensitive to a different wavelength of a set of wavelengths.