Gas sensor

a technology of gas sensor and sensor body, applied in the field of gas sensor, can solve the problems of limited sensitivity, limited selectivity, and suffer from the above described techniques, and achieve the effects of accurate/selective identification of the presence of one or more, increased selectivity, and convenient differentiation

Inactive Publication Date: 2017-03-02
SENSORHUT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent describes a method for analyzing multiple signals from multiple regions with different properties using multi-component analysis. This allows for more accurate and selective identification of targets. The method also involves operating at multiple temperatures to gain further selectivity and specificity. By using porous materials with small pores and a separate substrate, the method can provide information on absorption spectrum and facilitate absorption of analytes through the entire outer surface in a lateral direction. This makes the method particularly useful in analyzing urine samples to provide information on kidney function and associated diseases such as kidney disease and cancers.

Problems solved by technology

However these approaches rely on interference techniques to measure the change in refractive index of porous silicon, which limits their selectivity.
By contrast, typical waveguide-based sensors provide the target material on an outer surface of the waveguide and rely on the interaction of an evanescent wave (of light propagating within the waveguide) with the analyte, which has limited sensitivity.
As noted, the above described techniques suffer from various problems including a lack of specificity and sensitivity.

Method used

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Experimental program
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Embodiment Construction

[0046]We will describe techniques for optical spectroscopy of analytes in the pores of a porous waveguide. Some initial background material is helpful for understanding the invention:

Spectroscopy

[0047]Optical absorption spectroscopy is based on illuminating a chemical compound with a light and measuring the light absorption as a result of a presence of that chemical compound. Different molecules absorb light of different wavelengths. An absorption spectrum will show a number of absorption bands corresponding to structural groups within the molecule.

[0048]Absorbance is directly proportional to the path length, b, and the concentration, c, of the absorbing species. Beer's Law states that A=cbc, where £ is a constant of proportionality, called the absorbtivity.

[0049]The radiation can be of any wavelength ranging from the UV to IR and even THz.

Porous Silicon

[0050]Porous silicon is typically fabricated using electrochemical etching. The porosity of the fabricated layer depends on several...

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Abstract

We describe a method of selectively detecting the presence of an analyte. The method comprises providing a waveguide with a core comprising porous material; absorbing an analyte sample into the porous material of the core such that the analyte sample is held within pores of the core; waveguiding radiation along the waveguide to an output; measuring spectral features of the output radiation due to absorption or scattering of said waveguided radiation by the absorbed analyte sample; and selectively identifying the presence of a target analyte in the sample from the spectral features. In embodiments spectral features are measured for multiple different waveguide core regions having different physical / chemical properties modified to provide additional selectivity to the target analyte(s), and these measurements are combined to identify the target analyte.

Description

FIELD OF THE INVENTION[0001]This invention relates to methods and apparatus for selectively detecting the presence of an analyte, in particular a gas (vapour), and to methods of fabricating sensors for such methods / apparatus.BACKGROUND TO THE INVENTION[0002]Many sensors based on porous silicon have been reported, and some use porous silicon waveguides. In particular we have previously described sensors which measure the change in refractive index of a porous waveguide: Tanya Hutter, Nikos Bamiedakis and Stephen Elliott, “Theoretical Study of Porous Silicon Waveguides and Their Applicability for Vapour Sensing”, Proceedings of the COMSOL Conference 2010 Paris, 2010; Tanya Hutter, Stephen R. Elliott and Shlomo Ruschin, Dynamic Range Enhancement and Phase-Ambiguity Elimination in Wavelength-Interrogated Interferometer Sensor, Sensors and Actuators B, 178, 593-597, 2013. Other work on porous silicon waveguides for biosensing can be found in L. Haji et al (2012). However these approaches...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): G01N15/14G01N21/31G01N33/497G01N21/65
CPCG01N15/1434G01N21/65G01N21/31G01N2201/08G01N2033/4975G01N2015/0065G01N33/497B82Y20/00G01N21/253G01N21/552G01N21/7703G01N2021/0346G01N2021/7713G01N2021/7783G01N2021/8542G01N33/4975G01N21/3504G01N21/3577G01N21/77G01N15/01G02B6/1225
InventorHUTTER, TANYA
OwnerSENSORHUT