Hyperspectral Light Source Using Rotating Multi-Bandpass Filter

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Solution Overview

Problem

There is a need for small, low-cost tunable light sources for hyperspectral imaging applications such as mouth or eye imaging, microscopy, and endoscopy, as existing solutions are often bulky and expensive.

Innovation Solution

A hyperspectral light source system comprising a broadband light source, a rotating multi bandpass filter, and a tunable filter, such as a Fabry-Perot Interferometer, which allows for the selection of specific passbands by adjusting the rotation angle of the multi bandpass filter and the mirror gap of the tunable filter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional tunable light sources are used for hyperspectral imaging, then spectral tuning capability is achieved, but device size and cost increase

Engineering Contradiction:

Improvespectral tuning capabilityVSAvoiddevice size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent implements a nested filter configuration where a first optical filter with broader passband is nested with a second optical filter having a narrower passband. The second filter is positioned within the optical path of the first filter, creating a compact cascaded filtering system. This nesting arrangement allows spectral tuning through multiple filters while maintaining a small device footprint, directly resolving the contradiction between spectral adaptability and device size.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Adaptability or versatility

If conventional tunable light sources are used for hyperspectral imaging, then spectral tuning capability is achieved, but device cost increases

Engineering Contradiction:

Improvespectral tuning capabilityVSAvoiddevice cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent divides the spectral filtering function into multiple independent optical filters, each responsible for a specific wavelength range or passband. This segmentation allows each filter to be optimized independently and potentially manufactured using simpler, lower-cost processes. The modular segmented filter design achieves spectral tuning capability while reducing overall device complexity and manufacturing cost compared to conventional monolithic tunable sources.

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If broadband light is passed through filters to achieve narrowband output, then spectral selectivity is improved, but light intensity decreases

Engineering Contradiction:

Improvespectral selectivityVSAvoidlight intensity

Core Design Contradiction:

Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent merges the transmission characteristics of multiple optical filters to achieve the desired narrowband spectral output. By combining the filtering effects of the first and second filters in series, the system achieves high spectral selectivity. The merging of multiple filter functions allows for optimized light throughput while maintaining narrowband selection, mitigating the intensity loss that would occur with a single aggressive filter.

Inventive Principle:

Principle #5Merging (Combining)

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

The system enables the creation of a compact, low-cost wavelength-tunable hyperspectral light source, capable of producing narrowband light signals with controlled passbands, suitable for various hyperspectral imaging applications.

Implementation Method 1

a rotating multi bandpass filter arranged to pass through a part of the broadband light signal on one of multiple passbands of the hyperspectral light source system

Methodology Applied

Scientific EffectBandpass filtering: Filter (optical)

Implementation Method 2

a tunable filter adjusted to pass through the part of the broadband light signal, coming from the rotating multi bandpass filter, on said one passband of the hyperspectral light source system, such as a Fabry-Perot Interferometer

Methodology Applied

Scientific EffectFabry-Perot interference: Fabry-Perot Interferometer

Data Source

PatentUS12326238B2Hyperspectral light source

Publication Date: 2025.06.10 TEKNOLOGIAN TUTKIMUSKESKUS VTT OY

AI summary

According to an example aspect of the present invention, there is provided a hyperspectral light source system, comprising a broadband light source arranged to generate and radiate a broadband light signal, a rotating multi bandpass filter arranged to pass through a part of the broadband light signal on one of multiple passbands of the hyperspectral light source system, wherein a rotation angle of the rotating multi bandpass filter determines the part of the broadband light signal that passes through the rotating multi bandpass filter and a tunable filter adjusted to pass through the part of the broadband light signal, coming from the rotating multi bandpass filter, on said one passband of the hyperspectral light source system.