Mosaic Filter Lens Array for Multi-Gas IR Detection

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Solution Overview

Problem

Existing anesthetic and respiratory gas monitoring methods using multi-surfaced mirrors suffer from low signal resolution and signal-to-noise ratio due to IR beam splitting, limiting the detection of multiple gases and experiencing IR beam loss, which restricts monitoring to four or six gases.

Innovation Solution

An apparatus employing a multi-spectral mosaic filter and lens array with a composite thermal sensing focal plane array and signal processor, utilizing a patterned thermally reflective metal layer to minimize cross-talk and enhance signal-to-noise performance, and featuring individual thermal sensing focal plane arrays with unique gain, bias voltage, and frame rates for each data channel, allowing for the identification and concentration determination of multiple gas species.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a multi-surfaced mirror is used to create several infrared beams traveling in different directions, then multiple gases can be analyzed in parallel, but signal resolution and signal-to-noise ratio deteriorate due to IR beam splitting and energy loss

Engineering Contradiction:
Improveparallel gas analysis capabilityVSAvoidsignal resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the detection system into multiple independent focal plane arrays, with each array dedicated to detecting a specific gas type. This eliminates the need for beam splitting by providing separate detection paths for different gases, thereby maintaining full signal intensity for each detection channel while enabling parallel analysis of multiple gases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-dimension beam splitting approach to a multi-dimensional array detection approach. By using two-dimensional focal plane arrays with multiple pixels that can be selectively activated, the system achieves parallel gas analysis without dividing the infrared beam, thus preserving signal strength while adding dimensional capability for simultaneous multi-gas detection.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If a multi-surfaced mirror is used to split the infrared beam into multiple directions, then multiple gas channels can be created, but signal-to-noise ratio deteriorates due to IR beam energy loss

Engineering Contradiction:
Improvemulti-channel detection capabilityVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The detection system is segmented into multiple focal plane arrays, each optimized for specific gas detection. This segmentation allows each detector to receive the full infrared signal intensity without division, maintaining high signal-to-noise ratio while achieving multi-channel detection capability through the array configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each focal plane array is designed with specific local quality characteristics optimized for detecting particular gas types. The arrays can be selectively activated based on which gases need to be detected, providing adaptable multi-channel capability without the energy loss associated with beam splitting mirrors.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the number of sides to the mirror increases to detect more gases, then more gas species can be monitored, but signal intensity at detectors decreases due to increased beam splitting

Engineering Contradiction:
Improvenumber of detectable gas speciesVSAvoidsignal intensity at detectors
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

Instead of increasing mirror complexity to detect more gases, the patent segments the detection into multiple focal plane arrays. Each array detects specific gases with full signal intensity, allowing the system to monitor multiple gas species simultaneously without the signal intensity degradation that would result from increased beam splitting.

Inventive Principle:
Principle #1Segmentation

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 solution significantly improves signal resolution and signal-to-noise ratio, enabling the simultaneous real-time identification and concentration determination of multiple anesthetic and respiratory gas species, overcoming the limitations of previous technologies.

Implementation Method 1

lens structures and long wave infrared (IR) band-pass filter elements configured to receive a broadband infrared (IR) energy beam and to focus and spectrally filter the received broadband IR energy beam into a plurality of cones of focused and spectrally filtered IR beams

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 2

long wave infrared (IR) band-pass filter elements configured to receive a broadband infrared (IR) energy beam and to focus and spectrally filter the received broadband IR energy beam

Methodology Applied
Scientific EffectBand-pass filtering: Filter (optical)

Implementation Method 3

a patterned thermally reflective metal disposition layer disposed on or overlying a first surface at least between adjacent lens structures and a patterned thermally reflective metal disposition layer disposed on or overlying a second surface at least between adjacent filter elements

Methodology Applied
Scientific EffectThermal reflection: Reflection

Implementation Method 4

composite thermal sensing focal plane array that comprises a plurality of individual thermal sensing focal plane arrays with integrated read out integrated circuits

Methodology Applied
Scientific EffectThermal sensing: Bolometer

Data Source

PatentEP3555593B1Microbolometer focal plane array with integrated array of mosaic multi-spectral band-pass filters and focusing lenses array for simultaneous real-time anesthetic and respiratory gas concentration detection and measurement signal processing
Publication Date: 2021.03.31 KONINKLIJKE PHILIPS NV
  • EP3555593B1 patent drawingFigure 1~2
  • EP3555593B1 patent drawingFigure 3~4
  • EP3555593B1 patent drawingFigure 5

AI summary

A gas monitoring apparatus (10) identifies a target anesthetic or respiratory gas species and determines a concentration thereof. The gas monitor includes a multi-spectral mosaic filter and lens array (12), a composite thermal sensing focal plane array (26), and a signal processor (32). The mosaic filter and lens array (12) comprises a 2D array of lens structures (14) and long wave infrared (IR) band-pass filter elements (16) having a patterned thermally reflective metal disposition layer (18,22) disposed on a first and/or second surface (20,24) between adjacent lens structures and/or filter elements, respectively. The composite focal plane array (26) includes a plurality of individual thermal sensing focal plane arrays (28) with integrated read out integrated circuits (ROIC) that output a respective sensed channel data (36). The signal processor (32) receives the sensed channel data outputs (36) and generates an output indicative of the identification (50) and/or concentration (52) of the target gas based on an oversampling of an absorption signal, on a frame by frame basis and/or an image stacking basis.