Optically-based chemical detection system
First Claim
1. A vehicle that generates a gas comprised of a plurality of different chemical species, the vehicle comprising:
- means for sampling at least a portion of the gas, said sampling means having an optical input port and an optical output port;
an optical source having an output coupled to said optical input port of said sampling means, said optical source generating electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and
a plurality of radiation detector means individual ones of which have an input coupled to said optical output port of said sampling means, individual ones of said radiation detector means comprising an integral input filter for passing wavelengths within a band of wavelengths and being responsive to the band of wavelengths, that includes wavelengths that are absorbed by at least one of the predetermined ones of the chemical species, for determining an amount of the electromagnetic radiation, within the band of wavelengths, that is transmitted through the gas within said sampling means, wherein individual ones of said input filters are deposited upon a radiation receiving surface of an associated one of said radiation detector devices.
4 Assignments
0 Petitions
Accused Products
Abstract
An in-situe chemical gas or fluid analyzer for vehicles, industrial, environmental and process control applications. As applied to a vehicle (1) having an internal combustion engine, the analyzer includes: (i) a source of electromagnetic radiation (14, 16); and (ii) a sampling cell (12) which collects emission gases of interest and which is capable of withstanding hostile environments while preserving a "clear" optical path between the sensor sampling cell and the source of radiation. The analyzer further includes: (iii) a solid state sensor (24, 26, 28, 30, 32 ) of monolithic construction which selectively detects electromagnetic radiation that is absorbed or emitted by one or more chemical species of interest, that compensates for temporal and spatial variations in illumination level provided by the source, and that provides an electrical signal output, in either analog or digital format, that is related to the measured concentrations. The sensor includes, in combination, a plurality of highly sensitive electromagnetic radiation detectors (26), spectral filters (24) which may utilize multiple layers of deposited dielectric thin films and/or selectively absorbing layers, and low noise electronics which performs a variety of functions including amplification (28), multiplexing (30), analog to digital (A/D) conversion (33), signal processing (32), and input/output (I/O). In a presently preferred embodiment each radiation detector is a thermopile detector that is integrated upon a common substrate with the support electronics and an associated optical bandpass filter.
78 Citations
46 Claims
-
1. A vehicle that generates a gas comprised of a plurality of different chemical species, the vehicle comprising:
-
means for sampling at least a portion of the gas, said sampling means having an optical input port and an optical output port; an optical source having an output coupled to said optical input port of said sampling means, said optical source generating electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and a plurality of radiation detector means individual ones of which have an input coupled to said optical output port of said sampling means, individual ones of said radiation detector means comprising an integral input filter for passing wavelengths within a band of wavelengths and being responsive to the band of wavelengths, that includes wavelengths that are absorbed by at least one of the predetermined ones of the chemical species, for determining an amount of the electromagnetic radiation, within the band of wavelengths, that is transmitted through the gas within said sampling means, wherein individual ones of said input filters are deposited upon a radiation receiving surface of an associated one of said radiation detector devices. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A vehicle that generates a gas comprised of a plurality of different chemical species, the vehicle comprising:
-
means for sampling at least a portion of the gas, said sampling means having an optical input port and an optical output port; an optical source having an output coupled to said optical input port of said sampling means, said optical source generating electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and a plurality of radiation detector means individual ones of which have an input coupled to said optical output port of said sampling means, individual ones of said radiation detector means being responsive to a band of wavelengths that includes wavelengths that are absorbed by at least one of the predetermined ones of the chemical species for determining an amount of the electromagnetic radiation, within the band of wavelengths, that is transmitted through the gas within said sampling means; wherein said sampling means is comprised of a sampling cell having at least one window that is substantially transparent to the electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and
further comprising means for removing an accumulation of an emission gas constituent from said window.
-
-
14. A spectroscopic system, comprising:
-
means for sampling a gas or a liquid that is comprised of a plurality of different chemical species, said sampling means having an optical input port and an optical output port; an optical source having an output coupled to said optical input port of said sampling means, said optical source generating electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and a plurality of radiation detector means individual ones of which have an input coupled to said optical output port of said sampling means, individual ones of said radiation detector means being responsive to a band of wavelengths that includes wavelengths that are absorbed by at least one of the predetermined ones of the chemical species for determining an amount of the electromagnetic radiation, within the band of wavelengths, that is transmitted through the sample within said sampling means, wherein individual ones of said radiation detector means are comprised of a radiation detector device that is fabricated within or upon a surface of a common substrate, and further comprising a plurality of amplifier circuits individual ones of which have an input coupled to an output of one of said radiation detector devices, said plurality of amplifier circuits also being fabricated within or upon the surface of said common substrate; and wherein individual ones of said radiation detector means are further comprised of an input filter for passing wavelengths within the band of wavelengths, said input filter being a multi-layered filter that is deposited upon a radiation receiving surface of said radiation detector device. - View Dependent Claims (15, 16, 17, 18, 19, 20)
-
-
21. A spectrographic system comprising:
-
means for sampling a gas or a liquid that is comprised of a plurality of different chemical species, said sampling means having an optical input port and an optical output port; an optical source having an output coupled to said optical input port of said sampling means, said optical source generating electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and a plurality of radiation detector means individual ones of which have an input coupled to said optical output port of said sampling means, individual ones of said radiation detector means being responsive to a band of wavelengths that includes wavelengths that are absorbed by at least one of the predetermined ones of the chemical species for determining an amount of the electromagnetic radiation, within the band of wavelengths, that is transmitted through the sample within said sampling means, wherein individual ones of said radiation detector means are comprised of a radiation detector device that is fabricated within or upon a surface of a common substrate, and further comprising a plurality of amplifier circuits individual ones of which have an input coupled to an output of one of said radiation detector devices, said plurality of amplifier circuits also being fabricated within or upon the surface of said common substrate; wherein said sampling means includes at least one window that is substantially transparent to the electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and further comprising means for removing an accumulation of a constituent of said gas or liquid from said at least one window.
-
-
22. An electronic component for use in detecting a concentration of individual ones of a plurality of chemical species, comprising:
-
an optical input port; a substrate; a plurality of radiation detector means individual ones of which have an input coupled to said optical input port, individual ones of said radiation detector means being responsive to a band of wavelengths that includes wavelengths that are absorbed by at least one of the predetermined ones of the chemical species, individual ones of said radiation detector means being comprised of a radiation detector device that is fabricated within or upon a surface of the substrate; and a plurality of amplifier circuits individual ones of which have an input coupled to an output of one of said radiation detector devices, said plurality of amplifier circuits also being fabricated within or upon the surface of said substrate; wherein individual ones of said radiation detector means are further comprised of an input filter for passing wavelengths within the band of wavelengths, said input filter being a multi-layered filter that is deposited upon a radiation receiving surface of said radiation detector device. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
-
-
34. A multispectral sensor system for sensing one or more different chemical species within a flow, comprising:
-
means for sampling at least a portion of the flow, said sampling means having an optical input port and an optical output port; an optical source having an output coupled to said optical input port of said sampling means, said optical source generating electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and a monolithic sensor assembly comprised of a plurality of radiation detector means individual ones of which have an input coupled to said optical output port of said sampling means, individual ones of said radiation detector means being responsive to a band of wavelengths that includes wavelengths that are absorbed by at least one of the predetermined ones of the chemical species for determining an amount of the electromagnetic radiation, within the band of wavelengths, that is transmitted through the sampled portion of the flow; wherein individual ones of said radiation detector means are fabricated upon or within a surface of a common substrate and are comprised of a radiation detector device having an integral input filter for passing wavelengths within the band of wavelengths, said integral input filter being deposited upon a radiation receiving surface of said radiation detector device. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
-
-
46. A multispectral sensor system for sensing one or more different chemical species within a flow, comprising:
-
means for sampling at least a portion of the flow, said sampling means having an optical input port and an optical output port; an optical source having an output coupled to said optical input port of said sampling means, said optical source generating electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and a monolithic sensor assembly comprised of a plurality of radiation detector means individual ones of which have an input coupled to said optical output port of said sampling means, individual ones of said radiation detector means being responsive to a band of wavelengths that includes wavelengths that are absorbed by at least one of the predetermined ones of the chemical species for determining an amount of the electromagnetic radiation, within the band of wavelengths, that is transmitted through the sampled portion of the flow; wherein said sampling means is comprised of a sampling cell having at least one window that is substantially transparent to the electromagnetic radiation having wavelengths that are absorbed by predetermined ones of the chemical species; and further comprising means for removing an accumulation of a flow constituent from said window.
-
Specification