US20180217044A1 - Forward scatter in particulate matter sensor - Google Patents
Forward scatter in particulate matter sensor Download PDFInfo
- Publication number
- US20180217044A1 US20180217044A1 US15/423,302 US201715423302A US2018217044A1 US 20180217044 A1 US20180217044 A1 US 20180217044A1 US 201715423302 A US201715423302 A US 201715423302A US 2018217044 A1 US2018217044 A1 US 2018217044A1
- Authority
- US
- United States
- Prior art keywords
- light
- particulate matter
- photodiode
- airflow channel
- waveguide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000013618 particulate matter Substances 0.000 title claims abstract description 87
- 238000000034 method Methods 0.000 claims abstract description 25
- 239000002245 particle Substances 0.000 claims abstract description 14
- 239000012080 ambient air Substances 0.000 claims description 3
- 239000003570 air Substances 0.000 description 7
- 230000037361 pathway Effects 0.000 description 5
- 230000002452 interceptive effect Effects 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/10—Investigating individual particles
- G01N15/14—Optical investigation techniques, e.g. flow cytometry
- G01N15/1434—Optical arrangements
- G01N15/1436—Optical arrangements the optical arrangement forming an integrated apparatus with the sample container, e.g. a flow cell
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
- G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
- G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
- G01N21/534—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke by measuring transmission alone, i.e. determining opacity
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/06—Investigating concentration of particle suspensions
- G01N15/075—Investigating concentration of particle suspensions by optical means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N2015/0042—Investigating dispersion of solids
- G01N2015/0046—Investigating dispersion of solids in gas, e.g. smoke
-
- G01N2015/0693—
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N2021/4704—Angular selective
- G01N2021/4707—Forward scatter; Low angle scatter
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/061—Sources
- G01N2201/06113—Coherent sources; lasers
- G01N2201/0612—Laser diodes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/08—Optical fibres; light guides
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/12—Circuits of general importance; Signal processing
Definitions
- a particulate matter sensor or dust sensor may be used to determine a quality of air, for example in a quality of air that is input to and/or output from an air cleaner.
- environmental air may have high concentrations of particulate matter of different sizes. If the concentration of such particulate matter is high enough, it may be deleterious to human health.
- Consumers may wish to purchase and install air cleaners for the residences to improve the quality of air breathed in the home.
- Such consumer grade air cleaners may desirably be modestly priced and compact in size.
- a particulate matter sensor may comprise an airflow channel; a light source configured to pass light through the airflow channel; an airflow generator configured to generate airflow into the airflow channel; a waveguide configured to direct light from the light source after it passes through the airflow channel and scatters off of particulate matter within the airflow channel; a photodiode configured to receive light scattered by the waveguide; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
- a method for determining the concentration of particulate matter within an environment may comprise allowing ambient air to enter a particulate matter sensor; generating an updraft into an airflow channel within the particulate matter sensor; powering a light source within the particulate matter sensor; directing the light source through the airflow channel; receiving, by a waveguide, scattered light that is scattered by particulate matter within the airflow channel; directing, by the waveguide, the scattered light toward a photodiode; and determining a mass concentration of particles in the airflow channel based on an output of the photodiode.
- a particulate matter sensor may comprise an airflow channel; a laser diode; a housing configured to contain the elements of the sensor; an airflow generator configured to generate airflow into the airflow channel; a photodiode configured to receive light produced by the laser diode; a waveguide positioned between the laser diode and the photodiode, configured to direct light scattered by particulate matter within the airflow channel toward the photodiode; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
- FIG. 1 illustrates a schematic diagram of a particulate matter sensor according to an embodiment of the disclosure.
- FIGS. 2A-2B illustrate a waveguide for use in a particulate matter sensor according to an embodiment of the disclosure.
- FIG. 3 illustrates a perspective view of a particulate matter sensor according to an embodiment of the disclosure.
- FIGS. 4A-4B illustrate a waveguide for use in a particulate matter sensor according to an embodiment of the disclosure.
- FIG. 5 illustrates a perspective view of a particulate matter sensor according to an embodiment of the disclosure.
- FIG. 6 illustrates an assembled particulate matter sensor according to an embodiment of the disclosure.
- component or feature may,” “can,” “could,” “should,” “would,” “preferably,” “possibly,” “typically,” “optionally,” “for example,” “often,” or “might” (or other such language) be included or have a characteristic, that particular component or feature is not required to be included or to have the characteristic. Such component or feature may be optionally included in some embodiments, or it may be excluded.
- Embodiments of the disclosure include systems and methods for directing scattered light toward a photodiode within a particulate matter sensor.
- Typical particulate matter sensors may use a light source and a fan structure to direct airflow through the light source.
- the scattered light detected by the photodiode may be scattered by particulate matter in an airflow pathway.
- One or more waveguides may direct the scattered light toward the photodiode.
- Embodiments of the disclosure may relate to forward scattering of light scattered from particulate matter. Greater light scattering occurs in the forward direction and therefore should produce a stronger signal than a typical particulate matter sensor configured to detect scattered light at 90 degrees. However, the forward scatter signal produced is analog, requiring a slightly different signal analysis. This may be accomplished by a computing system within the sensor.
- Utilizing the increased amount of scattered light that can be collected by forward scattering may generate a stronger, enhanced signal generated by the photodiode.
- the increased intensity may allow for smaller size particles to be detected by the sensor.
- the sensor may comprise a laser diode (or another similar light source), one or more waveguides (such as an ellipsoidal or spherical mirror), a photodiode detector, and walls and/or baffles within the sensor to ensure that the light is directed toward the intended scatter location.
- FIG. 1 illustrates an exemplary particulate matter sensor 100 comprising a housing 102 with an airflow channel 108 through the housing 102 .
- the airflow channel 108 may direct airflow 120 through the housing 102 and through a beam 111 from a laser diode 110 (or another light source).
- the airflow channel 108 is shown as a straight pathway, but in other embodiments, the airflow channel 108 may comprise angles or curves within the sensor housing 102 .
- the beam 111 may be received by a photodiode 112 , where any light scattered away by the particulate matter in the in the airflow 120 may reduce the beam 111 that is detected by the photodiode 112 .
- the photodiode 112 may be configured to detect light that is scattered off of the particulate matter within the airflow 120 .
- the photodiode 112 may comprise or be coupled to a computing device 113 configured to determine a mass concentration of particles in the airflow channel 108 based on an output of the photodiode.
- the sensor 100 may comprise one or more waveguides 114 configured to amplify the light that is directed toward the photodiode 112 .
- the waveguide(s) 114 may optionally comprise a light trap 115 located in the path of the beam 111 produced by the laser diode 110 .
- the laser diode 110 may be placed close to the scatter point (where the beam 111 contacts particulate matter in the airflow 120 ) and the light trap 115 to avoid scatter from other regions of the sensor 100 .
- the beam 111 produced by the laser diode may be collimated with a diameter of approximately 1 to 2 millimeters.
- the light trap 115 may comprise a tube shape configured to absorb the beam 111 .
- the light trap 115 may comprise a black tube located within the waveguide 114 .
- scattered light 140 may bounce off of particulate matter in the airflow 120 , wherein the scattered light 140 may be directed at an angle to the beam 111 .
- This scattered light 140 may be captured by the waveguide 114 , and may be directed toward the photodiode 112 .
- Scattered light 140 may comprise light reflected off of particulate matter within a given angle from the beam 111 that is then directed toward the waveguide 114 and is scattered forward by the waveguide 114 .
- the photodiode 112 may only receive the light scattered off of the particulate matter. For this reason, the beam 111 produced by the laser diode 110 may be trapped and/or blocked from reaching the photodiode 112 .
- a light trap 115 may be placed within the waveguide(s) 114 , wherein the light trap 115 may contain the beam 111 and prevent it from reaching the photodiode 112 . Additionally, the light trap 115 may be configured to prevent the beam 111 from reflecting back into the airflow channel 108 .
- the sensor 100 may comprise an airflow generator 130 configured to provide airflow 120 through the airflow channel 108 .
- the airflow generator 130 may draw airflow 120 into the housing 102 via an inlet 104 , where the airflow 120 may pass through the beam 111 of the laser diode 110 , and may be directed out of the housing 102 via an outlet 106 .
- the airflow generator 130 may comprise a mechanical airflow generator, such as a fan, a blade, and/or a flipper.
- the airflow generator 130 may comprise a conduction airflow generator.
- the airflow generator 130 may comprise any element that is configured to produce airflow through the airflow channel 108 . As shown in FIG. 1 , the airflow generator 130 may be located within the housing 102 of the sensor 100 . Alternatively, the airflow generator 130 may be located external to the housing 102 of the sensor 100 .
- FIGS. 2A-2B illustrate exemplary embodiments of a waveguide 214 which may be similar to the waveguide(s) 114 described above.
- the waveguide 214 may comprise a first condensing lens 202 and a second condensing lens 204 .
- the first condensing lens 202 may be configured to receive scattered light 140 that is scattered off of particulate matter 220 in the airflow 120 .
- the scattered light 140 received by the first condensing lens 202 may be within a range of angles indicated by the area 240 .
- the scattered light 140 received by the first condensing lens 202 may be between approximately 10 to 40 degrees from the beam 111 produced by the laser diode 110 .
- the scattered light 140 received by the waveguide 214 may be at an angle greater than 5 degrees from the beam 111 . In some embodiments, the scattered light 140 received by the waveguide 214 may be at an angle less than 90 degrees from the beam 111 .
- the scattered light 140 received by the first condensing lens 202 may be directed to the second condensing lens 204 , where the second condensing lens 204 may direct the scattered light 140 to the photodiode 112 . Therefore, the photodiode 112 may measure light that is scattered off of particulate matter 220 within the airflow 120 .
- the waveguide 214 may also comprise a light trap 215 located within the first condensing lens 202 .
- the light trap 215 may be configured to prevent the beam 111 produced by the laser diode 110 from reaching the photodiode 112 .
- the light trap 215 may comprise one or more angled walls 216 configured to prevent the beam 111 from reflecting back into the pathway of the airflow 120 .
- FIG. 2B illustrates a detailed view of a waveguide 214 .
- the light trap 215 may extend through both the first condensing lens 202 and the second condensing lens 204 .
- the light trap 215 may comprise angled walls 216 forming a conical shape within the light trap 215 .
- the conical shape may efficiently trap the beam 111 produced by the laser diode 112 .
- the interior angled walls 216 may comprise a light absorbing coating or material.
- FIG. 3 illustrates a perspective view of the sensor 100 with the top of the housing 102 removed, where the waveguide 214 and light trap 215 are incorporated into the sensor 100 .
- the waveguide 214 may be located between the laser diode 110 and the photo diode 112 .
- the waveguide 214 may be at least partially contained by walls within the housing 102 .
- grooves 302 and 304 may be configured to hold the lenses 202 and 204 in place within the housing 102 .
- the grooves 302 and 304 as well as other walls within the housing 102 may be structured to reduce the contact area between the housing 102 and the active area on the surfaces of the waveguide 214 .
- the housing 102 may be designed to hold the waveguide 214 in place without interfering with the light that is scattered through the waveguides 214 .
- the airflow channel 108 may be formed by walls within the housing 102 .
- the inlet 104 may comprise one or more openings in the housing 102 .
- the outlet 106 may comprise one or more openings in the housing 102 .
- the sensor 100 may comprise a flipper 130 that may be controlled by a coil 132 located near the flipper 130 .
- the flipper 130 may be moved back and forth on an axis, pulling airflow into the airflow channel 108 via the inlet 104 .
- the airflow 120 may be forced through the airflow channel 108 toward the outlet 106 , passing through the beam 111 .
- the airflow channel 108 is shown as a straight pathway, but in other embodiments, the airflow channel 108 may comprise angles or curves within the sensor housing 102 .
- the coil 132 may be located within the housing 102 , adjacent to the flipper 130 .
- the flipper 130 may be located within the housing 102 near the inlet 104 .
- the flipper 130 may be located anywhere within the airflow channel 108 .
- the coil 132 may be located on one side of the airflow channel 108 while the additional waveguide 214 may be located on the opposite side of the airflow channel 108 . This may prevent the coil 132 from interfering with the waveguides 114 and/or photodiode 112 .
- the coil 132 may be positioned such that the size of the housing 102 may be as small as possible while containing all of the elements described.
- the flipper 130 may be attached to a wall or extended portion 103 of the housing 102 .
- the flipper 130 may comprise a magnet 134 attached to and/or incorporated into the flipper 130 .
- the flipper 130 may be controlled by a magnetic force generated by the electric coil 132 .
- the coil 132 may generate alternating electric fields to push and pull the flipper 130 by applying attractive and repulsive forces to the magnet 134 .
- One end of the flipper 130 may be secured to the housing 102 , and the magnet 134 may be located on the unattached portion of the flipper 130 .
- the flipper 130 can be biased in one direction by a spring or other biasing member (e.g., gravity, etc.).
- the coil 132 can then generate an attractive or repulsive force to move the flipper 130 against the bias force.
- the coil 132 can then cease generation of the attractive or repulsive force to allow the bias member to return the flipper 130 to the resting position. Repetition of this cycle can cause the flipper 130 to move back and forth within the airflow channel 108 .
- the movement of the flipper 130 may generate airflow 120 drawing it in through the inlet 104 .
- the particulate matter in the airflow 120 may be detected via the laser diode 110 and the photodiode 112 .
- the coil 132 may be configured to produce an electric field at a particular frequency to drive the magnet 134 , and therefore the flipper 130 , to swing back and forth.
- the frequency produced by the coil may be a square wave at approximately 3.3V.
- the frequency of the coil 132 may be controlled based on the determined airflow rate through the sensor 100 .
- the determined airflow rate can be determined using a correlation between the flipper movement speed and a flow rate, which can be determined using an equation, a look-up table, or another representation of the correlation.
- the coil 132 may be located at an angle to the flipper 130 , where the angle and position of the coil 132 may be adjusted and chosen based on the interaction between the coil 132 and the flipper 130 , to provide the strongest and most reliable effect from the coil 132 on the flipper 130 .
- FIGS. 4A-4B illustrate an exemplary embodiment of a waveguide 414 which may be similar to the waveguide(s) 114 described above.
- the waveguide 414 may comprise an ellipse mirror comprising two flat surfaces, wherein the flat surfaces function as an inlet 402 and outlet 404 of the waveguide 414 .
- the inlet 402 may be configured to receive scattered light 140 that is scattered off of particulate matter 420 in the airflow 120 .
- the scattered light 140 received by the inlet 402 may be within a range of angles from the beam 111 .
- the scattered light 140 received by the inlet 402 may be between approximately 10 to 40 degrees from the beam 111 produced by the laser diode 110 .
- the scattered light 140 received by the waveguide 414 may be at an angle greater than 10 degrees from the beam 111 .
- the scattered light 140 received by the inlet 402 may be directed through the ellipse mirror toward the outlet 404 , where the outlet 404 may direct the scattered light 140 to the photodiode 112 . Therefore, the photodiode 112 may measure light that is scattered off of particulate matter 420 within the airflow 120 .
- the waveguide 414 may also comprise a light trap 415 located within the ellipse mirror.
- the light trap 415 may be configured to prevent the beam 111 produced by the laser diode 110 from reaching the photodiode 112 .
- the light trap 415 may comprise one or more angled walls 416 configured to prevent the beam 111 from reflecting back into the pathway of the airflow 120 .
- FIG. 4B illustrates a detailed view of the waveguide 414 .
- the light trap 415 may extend through only a portion of the waveguide 414 , while in other embodiments, the light trap 415 may extend through the entire waveguide 414 .
- the light trap 415 may comprise angled walls 416 forming a conical shape within the light trap 415 . The conical shape may efficiently trap the beam 111 produced by the laser diode 110 .
- the interior angled walls 416 may comprise a light absorbing coating or material.
- FIGS. 4A-4B uses an ellipse mirror as the waveguide 414 .
- additional lenses may be used with the ellipse mirror and positioned around the waveguide 514 to collect even more scattered light from the region of interaction between the beam 111 and particulate matter.
- FIG. 5 illustrates a perspective view of the sensor 100 with the top of the housing 102 removed, where the waveguide 414 and light trap 415 are incorporated into the sensor 100 .
- the waveguide 414 may be located between the laser diode 110 and the photodiode 112 .
- the waveguide 414 may be at least partially contained by walls within the housing 102 .
- the walls within the housing 102 may be structured to reduce the contact area between the housing 102 and the active area on the surfaces of the waveguide 414 .
- the housing 102 may be designed to hold the waveguide 414 in place without interfering with the light that is scattered through the waveguides 414 .
- the airflow channel 108 may be formed by walls within the housing 102 .
- the inlet 104 may comprise one or more openings in the housing 102 .
- the outlet 106 may comprise one or more openings in the housing 102 .
- the airflow generator of the sensor 100 may comprise a flipper 130 , as described above in FIG. 3 .
- FIG. 6 illustrates an assembled particulate matter sensor 100 , wherein the housing 102 may comprise a top portion 602 that attaches to the housing 102 and covers the internal elements of the sensor 100 .
- a particulate matter sensor may comprise an airflow channel; a light source configured to pass light through the airflow channel; an airflow generator configured to generate airflow into the airflow channel; a waveguide configured to direct light from the light source after it passes through the airflow channel and scatters off of particulate matter within the airflow channel; a photodiode configured to receive light scattered by the waveguide; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
- a second embodiment can include the particulate matter sensor of the first embodiment, wherein the waveguide directs light that scatters between approximately 10 and 40 degrees from a beam produced by the light source.
- a third embodiment can include the particulate matter sensor of the first or second embodiments, wherein the waveguide directs light that scatters at least 5 degrees from the beam produced by the light source.
- a fourth embodiment can include the particulate matter sensor of any of the first to third embodiments, wherein the waveguide directs light that scatters less than 90 degrees from the beam produced by the light source.
- a fifth embodiment can include the particulate matter sensor of any of the first to fourth embodiments, wherein light scattered by the particulate matter is forward scattered by the waveguide toward the photodiode.
- a sixth embodiment can include the particulate matter sensor of any of the first to fifth embodiments, further comprising a light trap configured to prevent the beam produced by the light source from reaching the photodiode.
- a seventh embodiment can include the particulate matter sensor of the sixth embodiment, wherein the light trap is further configured to prevent the beam from reflecting back into the airflow channel.
- An eighth embodiment can include the particulate matter sensor of any of the first to seventh embodiments, wherein the sensor is a dust sensor.
- a ninth embodiment can include the particulate matter sensor of any of the first to eighth embodiments, wherein the light source is a laser diode.
- a method for determining the concentration of particulate matter within an environment may comprise allowing ambient air to enter a particulate matter sensor; generating an updraft into an airflow channel within the particulate matter sensor; powering a light source within the particulate matter sensor; directing the light source through the airflow channel; receiving, by a waveguide, scattered light that is scattered by particulate matter within the airflow channel; directing, by the waveguide, the scattered light toward a photodiode; and determining a mass concentration of particles in the airflow channel based on an output of the photodiode.
- An eleventh embodiment can include the method of the tenth embodiment, wherein the light source comprises a laser diode.
- a twelfth embodiment can include the method of the tenth or eleventh embodiments, further comprising directing scattered light within a range of angles from the light source toward the photodiode.
- a thirteenth embodiment can include the method of any of the tenth to twelfth embodiments, further comprising preventing a beam produced by the light source from reaching the photodiode.
- a fourteenth embodiment can include the method of any of the tenth to thirteenth embodiments, further comprising preventing the light source from directly reaching the photodiode by a light trap located within the waveguide.
- a fifteenth embodiment can include the method of the fourteenth embodiment, wherein determining the mass concentration of particles in the airflow channel is completed by a computing device connected to the photodiode.
- a particulate matter sensor may comprise an airflow channel; a laser diode; a housing configured to contain the elements of the sensor; an airflow generator configured to generate airflow into the airflow channel; a photodiode configured to receive light produced by the laser diode; a waveguide positioned between the laser diode and the photodiode, configured to direct light scattered by particulate matter within the airflow channel toward the photodiode; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
- a seventeenth embodiment can include the particulate matter sensor of the sixteenth embodiment, wherein the waveguide directs light that scatters less than 90 degrees from the beam produced by the light source.
- An eighteenth embodiment can include the particulate matter sensor of the sixteenth or seventeenth embodiments, further comprising a light trap configured to prevent the beam produced by the light source from reaching the photodiode.
- a nineteenth embodiment can include the particulate matter sensor of the eighteenth embodiment, wherein the light trap is further configured to prevent the beam from reflecting back into the airflow channel.
- a twentieth embodiment can include the particulate matter sensor of the eighteenth or nineteenth embodiments, wherein the light trap comprises one or more angled surfaces.
Landscapes
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Dispersion Chemistry (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
Embodiments relate generally to systems and methods for detecting particulate matter in the air. A particulate matter sensor may comprise an airflow channel; a light source configured to pass light through the airflow channel; an airflow generator configured to generate airflow into the airflow channel; a waveguide configured to direct light from the light source after it passes through the airflow channel and scatters off of particulate matter within the airflow channel; a photodiode configured to receive light scattered by the waveguide; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
Description
- Not applicable.
- Not applicable.
- Not applicable.
- A particulate matter sensor or dust sensor may be used to determine a quality of air, for example in a quality of air that is input to and/or output from an air cleaner. In some industrialized regions, environmental air may have high concentrations of particulate matter of different sizes. If the concentration of such particulate matter is high enough, it may be deleterious to human health. Consumers may wish to purchase and install air cleaners for the residences to improve the quality of air breathed in the home. Such consumer grade air cleaners may desirably be modestly priced and compact in size.
- In an embodiment, a particulate matter sensor may comprise an airflow channel; a light source configured to pass light through the airflow channel; an airflow generator configured to generate airflow into the airflow channel; a waveguide configured to direct light from the light source after it passes through the airflow channel and scatters off of particulate matter within the airflow channel; a photodiode configured to receive light scattered by the waveguide; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
- In an embodiment, a method for determining the concentration of particulate matter within an environment may comprise allowing ambient air to enter a particulate matter sensor; generating an updraft into an airflow channel within the particulate matter sensor; powering a light source within the particulate matter sensor; directing the light source through the airflow channel; receiving, by a waveguide, scattered light that is scattered by particulate matter within the airflow channel; directing, by the waveguide, the scattered light toward a photodiode; and determining a mass concentration of particles in the airflow channel based on an output of the photodiode.
- In an embodiment, a particulate matter sensor may comprise an airflow channel; a laser diode; a housing configured to contain the elements of the sensor; an airflow generator configured to generate airflow into the airflow channel; a photodiode configured to receive light produced by the laser diode; a waveguide positioned between the laser diode and the photodiode, configured to direct light scattered by particulate matter within the airflow channel toward the photodiode; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
- For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.
-
FIG. 1 illustrates a schematic diagram of a particulate matter sensor according to an embodiment of the disclosure. -
FIGS. 2A-2B illustrate a waveguide for use in a particulate matter sensor according to an embodiment of the disclosure. -
FIG. 3 illustrates a perspective view of a particulate matter sensor according to an embodiment of the disclosure. -
FIGS. 4A-4B illustrate a waveguide for use in a particulate matter sensor according to an embodiment of the disclosure. -
FIG. 5 illustrates a perspective view of a particulate matter sensor according to an embodiment of the disclosure. -
FIG. 6 illustrates an assembled particulate matter sensor according to an embodiment of the disclosure. - It should be understood at the outset that although illustrative implementations of one or more embodiments are illustrated below, the disclosed systems and methods may be implemented using any number of techniques, whether currently known or not yet in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, but may be modified within the scope of the appended claims along with their full scope of equivalents.
- The following brief definition of terms shall apply throughout the application:
- The term “comprising” means including but not limited to, and should be interpreted in the manner it is typically used in the patent context;
- The phrases “in one embodiment,” “according to one embodiment,” and the like generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present invention, and may be included in more than one embodiment of the present invention (importantly, such phrases do not necessarily refer to the same embodiment);
- If the specification describes something as “exemplary” or an “example,” it should be understood that refers to a non-exclusive example;
- The terms “about” or “approximately” or the like, when used with a number, may mean that specific number, or alternatively, a range in proximity to the specific number, as understood by persons of skill in the art field; and
- If the specification states a component or feature “may,” “can,” “could,” “should,” “would,” “preferably,” “possibly,” “typically,” “optionally,” “for example,” “often,” or “might” (or other such language) be included or have a characteristic, that particular component or feature is not required to be included or to have the characteristic. Such component or feature may be optionally included in some embodiments, or it may be excluded.
- Embodiments of the disclosure include systems and methods for directing scattered light toward a photodiode within a particulate matter sensor. Typical particulate matter sensors may use a light source and a fan structure to direct airflow through the light source. The scattered light detected by the photodiode may be scattered by particulate matter in an airflow pathway. One or more waveguides may direct the scattered light toward the photodiode.
- Embodiments of the disclosure may relate to forward scattering of light scattered from particulate matter. Greater light scattering occurs in the forward direction and therefore should produce a stronger signal than a typical particulate matter sensor configured to detect scattered light at 90 degrees. However, the forward scatter signal produced is analog, requiring a slightly different signal analysis. This may be accomplished by a computing system within the sensor.
- Utilizing the increased amount of scattered light that can be collected by forward scattering may generate a stronger, enhanced signal generated by the photodiode. The increased intensity may allow for smaller size particles to be detected by the sensor. The sensor may comprise a laser diode (or another similar light source), one or more waveguides (such as an ellipsoidal or spherical mirror), a photodiode detector, and walls and/or baffles within the sensor to ensure that the light is directed toward the intended scatter location.
-
FIG. 1 illustrates an exemplaryparticulate matter sensor 100 comprising ahousing 102 with anairflow channel 108 through thehousing 102. Theairflow channel 108 maydirect airflow 120 through thehousing 102 and through abeam 111 from a laser diode 110 (or another light source). Theairflow channel 108 is shown as a straight pathway, but in other embodiments, theairflow channel 108 may comprise angles or curves within thesensor housing 102. Thebeam 111 may be received by aphotodiode 112, where any light scattered away by the particulate matter in the in theairflow 120 may reduce thebeam 111 that is detected by thephotodiode 112. Alternatively, thephotodiode 112 may be configured to detect light that is scattered off of the particulate matter within theairflow 120. Thephotodiode 112 may comprise or be coupled to acomputing device 113 configured to determine a mass concentration of particles in theairflow channel 108 based on an output of the photodiode. - In some embodiments, the
sensor 100 may comprise one ormore waveguides 114 configured to amplify the light that is directed toward thephotodiode 112. The waveguide(s) 114 may optionally comprise alight trap 115 located in the path of thebeam 111 produced by thelaser diode 110. Thelaser diode 110 may be placed close to the scatter point (where thebeam 111 contacts particulate matter in the airflow 120) and thelight trap 115 to avoid scatter from other regions of thesensor 100. In some embodiments, thebeam 111 produced by the laser diode may be collimated with a diameter of approximately 1 to 2 millimeters. Thelight trap 115 may comprise a tube shape configured to absorb thebeam 111. In some embodiments, thelight trap 115 may comprise a black tube located within thewaveguide 114. - As shown in
FIG. 1 , scatteredlight 140 may bounce off of particulate matter in theairflow 120, wherein thescattered light 140 may be directed at an angle to thebeam 111. Thisscattered light 140 may be captured by thewaveguide 114, and may be directed toward thephotodiode 112. Scattered light 140 may comprise light reflected off of particulate matter within a given angle from thebeam 111 that is then directed toward thewaveguide 114 and is scattered forward by thewaveguide 114. - It may be desired for the
photodiode 112 to only receive the light scattered off of the particulate matter. For this reason, thebeam 111 produced by thelaser diode 110 may be trapped and/or blocked from reaching thephotodiode 112. As an example, alight trap 115 may be placed within the waveguide(s) 114, wherein thelight trap 115 may contain thebeam 111 and prevent it from reaching thephotodiode 112. Additionally, thelight trap 115 may be configured to prevent thebeam 111 from reflecting back into theairflow channel 108. - The
sensor 100 may comprise anairflow generator 130 configured to provideairflow 120 through theairflow channel 108. Theairflow generator 130 may drawairflow 120 into thehousing 102 via aninlet 104, where theairflow 120 may pass through thebeam 111 of thelaser diode 110, and may be directed out of thehousing 102 via anoutlet 106. Theairflow generator 130 may comprise a mechanical airflow generator, such as a fan, a blade, and/or a flipper. Theairflow generator 130 may comprise a conduction airflow generator. Theairflow generator 130 may comprise any element that is configured to produce airflow through theairflow channel 108. As shown inFIG. 1 , theairflow generator 130 may be located within thehousing 102 of thesensor 100. Alternatively, theairflow generator 130 may be located external to thehousing 102 of thesensor 100. -
FIGS. 2A-2B illustrate exemplary embodiments of awaveguide 214 which may be similar to the waveguide(s) 114 described above. In the embodiment shown inFIGS. 2A-2B , thewaveguide 214 may comprise afirst condensing lens 202 and asecond condensing lens 204. Thefirst condensing lens 202 may be configured to receive scattered light 140 that is scattered off ofparticulate matter 220 in theairflow 120. Thescattered light 140 received by thefirst condensing lens 202 may be within a range of angles indicated by thearea 240. Thescattered light 140 received by thefirst condensing lens 202 may be between approximately 10 to 40 degrees from thebeam 111 produced by thelaser diode 110. In some embodiments, thescattered light 140 received by thewaveguide 214 may be at an angle greater than 5 degrees from thebeam 111. In some embodiments, thescattered light 140 received by thewaveguide 214 may be at an angle less than 90 degrees from thebeam 111. - The
scattered light 140 received by thefirst condensing lens 202 may be directed to thesecond condensing lens 204, where thesecond condensing lens 204 may direct thescattered light 140 to thephotodiode 112. Therefore, thephotodiode 112 may measure light that is scattered off ofparticulate matter 220 within theairflow 120. - The
waveguide 214 may also comprise alight trap 215 located within thefirst condensing lens 202. Thelight trap 215 may be configured to prevent thebeam 111 produced by thelaser diode 110 from reaching thephotodiode 112. In some embodiments, thelight trap 215 may comprise one or moreangled walls 216 configured to prevent thebeam 111 from reflecting back into the pathway of theairflow 120. -
FIG. 2B illustrates a detailed view of awaveguide 214. In some embodiments, thelight trap 215 may extend through both thefirst condensing lens 202 and thesecond condensing lens 204. In some embodiments, thelight trap 215 may comprise angledwalls 216 forming a conical shape within thelight trap 215. The conical shape may efficiently trap thebeam 111 produced by thelaser diode 112. In some embodiments, the interior angledwalls 216 may comprise a light absorbing coating or material. -
FIG. 3 illustrates a perspective view of thesensor 100 with the top of thehousing 102 removed, where thewaveguide 214 andlight trap 215 are incorporated into thesensor 100. Thewaveguide 214 may be located between thelaser diode 110 and thephoto diode 112. Thewaveguide 214 may be at least partially contained by walls within thehousing 102. In some embodiments,grooves lenses housing 102. Thegrooves housing 102 may be structured to reduce the contact area between thehousing 102 and the active area on the surfaces of thewaveguide 214. In other words, thehousing 102 may be designed to hold thewaveguide 214 in place without interfering with the light that is scattered through thewaveguides 214. - As described above, the
airflow channel 108 may be formed by walls within thehousing 102. Theinlet 104 may comprise one or more openings in thehousing 102. Theoutlet 106 may comprise one or more openings in thehousing 102. - Additionally, the
sensor 100 may comprise aflipper 130 that may be controlled by acoil 132 located near theflipper 130. Theflipper 130 may be moved back and forth on an axis, pulling airflow into theairflow channel 108 via theinlet 104. Theairflow 120 may be forced through theairflow channel 108 toward theoutlet 106, passing through thebeam 111. Theairflow channel 108 is shown as a straight pathway, but in other embodiments, theairflow channel 108 may comprise angles or curves within thesensor housing 102. - The
coil 132 may be located within thehousing 102, adjacent to theflipper 130. Theflipper 130 may be located within thehousing 102 near theinlet 104. In some embodiments, theflipper 130 may be located anywhere within theairflow channel 108. In some embodiments, thecoil 132 may be located on one side of theairflow channel 108 while theadditional waveguide 214 may be located on the opposite side of theairflow channel 108. This may prevent thecoil 132 from interfering with thewaveguides 114 and/orphotodiode 112. Additionally, thecoil 132 may be positioned such that the size of thehousing 102 may be as small as possible while containing all of the elements described. - The
flipper 130 may be attached to a wall orextended portion 103 of thehousing 102. Theflipper 130 may comprise amagnet 134 attached to and/or incorporated into theflipper 130. Theflipper 130 may be controlled by a magnetic force generated by theelectric coil 132. Thecoil 132 may generate alternating electric fields to push and pull theflipper 130 by applying attractive and repulsive forces to themagnet 134. One end of theflipper 130 may be secured to thehousing 102, and themagnet 134 may be located on the unattached portion of theflipper 130. - In some embodiments, the
flipper 130 can be biased in one direction by a spring or other biasing member (e.g., gravity, etc.). Thecoil 132 can then generate an attractive or repulsive force to move theflipper 130 against the bias force. Thecoil 132 can then cease generation of the attractive or repulsive force to allow the bias member to return theflipper 130 to the resting position. Repetition of this cycle can cause theflipper 130 to move back and forth within theairflow channel 108. - The movement of the
flipper 130 may generateairflow 120 drawing it in through theinlet 104. The particulate matter in theairflow 120 may be detected via thelaser diode 110 and thephotodiode 112. Thecoil 132 may be configured to produce an electric field at a particular frequency to drive themagnet 134, and therefore theflipper 130, to swing back and forth. In some embodiments, the frequency produced by the coil may be a square wave at approximately 3.3V. In some embodiments, the frequency of thecoil 132 may be controlled based on the determined airflow rate through thesensor 100. In some embodiments, the determined airflow rate can be determined using a correlation between the flipper movement speed and a flow rate, which can be determined using an equation, a look-up table, or another representation of the correlation. In the embodiment shown, thecoil 132 may be located at an angle to theflipper 130, where the angle and position of thecoil 132 may be adjusted and chosen based on the interaction between thecoil 132 and theflipper 130, to provide the strongest and most reliable effect from thecoil 132 on theflipper 130. -
FIGS. 4A-4B illustrate an exemplary embodiment of awaveguide 414 which may be similar to the waveguide(s) 114 described above. In the embodiment shown inFIGS. 4A-4B , thewaveguide 414 may comprise an ellipse mirror comprising two flat surfaces, wherein the flat surfaces function as aninlet 402 andoutlet 404 of thewaveguide 414. - The
inlet 402 may be configured to receive scattered light 140 that is scattered off ofparticulate matter 420 in theairflow 120. Thescattered light 140 received by theinlet 402 may be within a range of angles from thebeam 111. Thescattered light 140 received by theinlet 402 may be between approximately 10 to 40 degrees from thebeam 111 produced by thelaser diode 110. In some embodiments, thescattered light 140 received by thewaveguide 414 may be at an angle greater than 10 degrees from thebeam 111. Thescattered light 140 received by theinlet 402 may be directed through the ellipse mirror toward theoutlet 404, where theoutlet 404 may direct thescattered light 140 to thephotodiode 112. Therefore, thephotodiode 112 may measure light that is scattered off ofparticulate matter 420 within theairflow 120. - The
waveguide 414 may also comprise alight trap 415 located within the ellipse mirror. Thelight trap 415 may be configured to prevent thebeam 111 produced by thelaser diode 110 from reaching thephotodiode 112. In some embodiments, thelight trap 415 may comprise one or moreangled walls 416 configured to prevent thebeam 111 from reflecting back into the pathway of theairflow 120. -
FIG. 4B illustrates a detailed view of thewaveguide 414. In some embodiments, thelight trap 415 may extend through only a portion of thewaveguide 414, while in other embodiments, thelight trap 415 may extend through theentire waveguide 414. In some embodiments, thelight trap 415 may comprise angledwalls 416 forming a conical shape within thelight trap 415. The conical shape may efficiently trap thebeam 111 produced by thelaser diode 110. In some embodiments, the interior angledwalls 416 may comprise a light absorbing coating or material. - The embodiment shown in
FIGS. 4A-4B uses an ellipse mirror as thewaveguide 414. However, in other embodiments, additional lenses may be used with the ellipse mirror and positioned around the waveguide 514 to collect even more scattered light from the region of interaction between thebeam 111 and particulate matter. -
FIG. 5 illustrates a perspective view of thesensor 100 with the top of thehousing 102 removed, where thewaveguide 414 andlight trap 415 are incorporated into thesensor 100. Thewaveguide 414 may be located between thelaser diode 110 and thephotodiode 112. Thewaveguide 414 may be at least partially contained by walls within thehousing 102. The walls within thehousing 102 may be structured to reduce the contact area between thehousing 102 and the active area on the surfaces of thewaveguide 414. In other words, thehousing 102 may be designed to hold thewaveguide 414 in place without interfering with the light that is scattered through thewaveguides 414. - As described above, the
airflow channel 108 may be formed by walls within thehousing 102. Theinlet 104 may comprise one or more openings in thehousing 102. Theoutlet 106 may comprise one or more openings in thehousing 102. The airflow generator of thesensor 100 may comprise aflipper 130, as described above inFIG. 3 . -
FIG. 6 illustrates an assembledparticulate matter sensor 100, wherein thehousing 102 may comprise atop portion 602 that attaches to thehousing 102 and covers the internal elements of thesensor 100. - In a first embodiment, a particulate matter sensor may comprise an airflow channel; a light source configured to pass light through the airflow channel; an airflow generator configured to generate airflow into the airflow channel; a waveguide configured to direct light from the light source after it passes through the airflow channel and scatters off of particulate matter within the airflow channel; a photodiode configured to receive light scattered by the waveguide; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
- A second embodiment can include the particulate matter sensor of the first embodiment, wherein the waveguide directs light that scatters between approximately 10 and 40 degrees from a beam produced by the light source.
- A third embodiment can include the particulate matter sensor of the first or second embodiments, wherein the waveguide directs light that scatters at least 5 degrees from the beam produced by the light source.
- A fourth embodiment can include the particulate matter sensor of any of the first to third embodiments, wherein the waveguide directs light that scatters less than 90 degrees from the beam produced by the light source.
- A fifth embodiment can include the particulate matter sensor of any of the first to fourth embodiments, wherein light scattered by the particulate matter is forward scattered by the waveguide toward the photodiode.
- A sixth embodiment can include the particulate matter sensor of any of the first to fifth embodiments, further comprising a light trap configured to prevent the beam produced by the light source from reaching the photodiode.
- A seventh embodiment can include the particulate matter sensor of the sixth embodiment, wherein the light trap is further configured to prevent the beam from reflecting back into the airflow channel.
- An eighth embodiment can include the particulate matter sensor of any of the first to seventh embodiments, wherein the sensor is a dust sensor.
- A ninth embodiment can include the particulate matter sensor of any of the first to eighth embodiments, wherein the light source is a laser diode.
- In a tenth embodiment, a method for determining the concentration of particulate matter within an environment may comprise allowing ambient air to enter a particulate matter sensor; generating an updraft into an airflow channel within the particulate matter sensor; powering a light source within the particulate matter sensor; directing the light source through the airflow channel; receiving, by a waveguide, scattered light that is scattered by particulate matter within the airflow channel; directing, by the waveguide, the scattered light toward a photodiode; and determining a mass concentration of particles in the airflow channel based on an output of the photodiode.
- An eleventh embodiment can include the method of the tenth embodiment, wherein the light source comprises a laser diode.
- A twelfth embodiment can include the method of the tenth or eleventh embodiments, further comprising directing scattered light within a range of angles from the light source toward the photodiode.
- A thirteenth embodiment can include the method of any of the tenth to twelfth embodiments, further comprising preventing a beam produced by the light source from reaching the photodiode.
- A fourteenth embodiment can include the method of any of the tenth to thirteenth embodiments, further comprising preventing the light source from directly reaching the photodiode by a light trap located within the waveguide.
- A fifteenth embodiment can include the method of the fourteenth embodiment, wherein determining the mass concentration of particles in the airflow channel is completed by a computing device connected to the photodiode.
- In a sixteenth embodiment, a particulate matter sensor may comprise an airflow channel; a laser diode; a housing configured to contain the elements of the sensor; an airflow generator configured to generate airflow into the airflow channel; a photodiode configured to receive light produced by the laser diode; a waveguide positioned between the laser diode and the photodiode, configured to direct light scattered by particulate matter within the airflow channel toward the photodiode; and a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
- A seventeenth embodiment can include the particulate matter sensor of the sixteenth embodiment, wherein the waveguide directs light that scatters less than 90 degrees from the beam produced by the light source.
- An eighteenth embodiment can include the particulate matter sensor of the sixteenth or seventeenth embodiments, further comprising a light trap configured to prevent the beam produced by the light source from reaching the photodiode.
- A nineteenth embodiment can include the particulate matter sensor of the eighteenth embodiment, wherein the light trap is further configured to prevent the beam from reflecting back into the airflow channel.
- A twentieth embodiment can include the particulate matter sensor of the eighteenth or nineteenth embodiments, wherein the light trap comprises one or more angled surfaces.
- While various embodiments in accordance with the principles disclosed herein have been shown and described above, modifications thereof may be made by one skilled in the art without departing from the spirit and the teachings of the disclosure. The embodiments described herein are representative only and are not intended to be limiting. Many variations, combinations, and modifications are possible and are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention(s). Furthermore, any advantages and features described above may relate to specific embodiments, but shall not limit the application of such issued claims to processes and structures accomplishing any or all of the above advantages or having any or all of the above features.
- Additionally, the section headings used herein are provided for consistency with the suggestions under 37 C.F.R. 1.77 or to otherwise provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Specifically and by way of example, although the headings might refer to a “Field,” the claims should not be limited by the language chosen under this heading to describe the so-called field. Further, a description of a technology in the “Background” is not to be construed as an admission that certain technology is prior art to any invention(s) in this disclosure. Neither is the “Summary” to be considered as a limiting characterization of the invention(s) set forth in issued claims. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims issuing from this disclosure, and such claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of the claims shall be considered on their own merits in light of this disclosure, but should not be constrained by the headings set forth herein.
- Use of broader terms such as “comprises,” “includes,” and “having” should be understood to provide support for narrower terms such as “consisting of,” “consisting essentially of,” and “comprised substantially of.” Use of the terms “optionally,” “may,” “might,” “possibly,” and the like with respect to any element of an embodiment means that the element is not required, or alternatively, the element is required, both alternatives being within the scope of the embodiment(s). Also, references to examples are merely provided for illustrative purposes, and are not intended to be exclusive.
- While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted or not implemented.
- Also, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component, whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.
Claims (20)
1. A particulate matter sensor comprising:
an airflow channel;
a light source configured to pass light through the airflow channel;
an airflow generator configured to generate airflow into the airflow channel;
a waveguide configured to direct light from the light source after it passes through the airflow channel and scatters off particulate matter within the airflow channel, wherein the waveguide includes a first condensing lens and a second condensing lens, wherein the first condensing lens is configured to receive scattered light that is scattered off the particulate matter within the airflow channel, and is configured to direct the received scattered light to the second condensing lens, and the second condensing lens is configured to direct the scattered light to a photodiode;
the photodiode is configured to receive the scattered light from the second condensing lens; and
a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
2. The particulate matter sensor of claim 1 , wherein the first condensing lens of the waveguide directs light that scatters between approximately 10 and 40 degrees from a beam produced by the light source.
3. The particulate matter sensor of claim 1 , wherein the first condensing lens of the waveguide directs light that scatters at least 5 degrees from the beam produced by the light source.
4. The particulate matter sensor of claim 1 , wherein the first condensing lens of the waveguide directs light that scatters less than 90 degrees from the beam produced by the light source.
5. The particulate matter sensor of claim 1 , wherein light scattered by the particulate matter is forward scattered by the waveguide toward the photodiode.
6. The particulate matter sensor of claim 1 , further comprising a light trap configured to prevent the beam produced by the light source from reaching the photodiode.
7. The particulate matter sensor of claim 6 , wherein the light trap is further configured to prevent the beam from reflecting back into the airflow channel.
8. The particulate matter sensor of claim 1 , wherein the first condensing lens includes a curved output surface and the second condensing lens includes a curved input surface, wherein the curved output surface of the first condensing lens faces the curved input surface of the second condensing lens.
9. The particulate matter sensor of claim 1 , wherein the light source is a laser diode.
10. A method for determining the concentration of particulate matter within an environment, the method comprising:
allowing ambient air to enter a particulate matter sensor;
generating an updraft into an airflow channel within the particulate matter sensor;
powering a light source within the particulate matter sensor to produce a light beam;
directing the light beam through the airflow channel;
receiving, by a first condensing lens of a waveguide, scattered light that is scattered by particulate matter within the airflow channel;
directing, by the first condensing lens of the waveguide, the scattered light to a second condensing lens of the waveguide;
directing, by the second condensing lens of the waveguide, the scattered light toward a photodiode; and
determining a mass concentration of particles in the airflow channel based on an output of the photodiode.
11. The method of claim 10 , wherein the light source comprises a laser diode.
12. The method of claim 10 , further comprising directing scattered light within a range of angles from the light source toward the photodiode.
13. The method of claim 10 , further comprising preventing the light beam produced by the light source from directly reaching the photodiode.
14. The method of claim 10 , further comprising preventing the light beam from directly reaching the photodiode by a light trap located within the waveguide.
15. The method of claim 10 , wherein determining the mass concentration of particles in the airflow channel is completed by a computing device operatively coupled to the photodiode.
16. A particulate matter sensor comprising:
an airflow channel;
a laser diode;
a housing configured to contain the elements of the sensor;
an airflow generator configured to generate airflow into the airflow channel;
a photodiode configured to receive light produced by the laser diode;
a waveguide positioned between the laser diode and the photodiode, configured to direct light scattered by particulate matter within the airflow channel toward the photodiode;
wherein the waveguide includes an ellipse mirror, the ellipse mirror having an inlet that is configured to receive light scattered by the particulate matter within the airflow channel, and the ellipse mirror is configured to direct at least some of the received scattered light toward the photodiode; and
a computing device coupled to the photodiode having a processor and a memory storing instructions which, when executed by the processor, determines a mass concentration of particles in the airflow channel based on an output of the photodiode.
17. The particulate matter sensor of claim 16 , wherein the ellipse mirror of the waveguide directs light that scatters less than 90 degrees from the beam produced by the light source.
18. The particulate matter sensor of claim 16 , further comprising a light trap configured to prevent the beam produced by the light source from directly reaching the photodiode.
19. The particulate matter sensor of claim 18 , wherein the light trap is further configured to prevent the beam from reflecting back into the airflow channel.
20. The particulate matter sensor of claim 18 , wherein the light trap comprises one or more angled surfaces.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/423,302 US20180217044A1 (en) | 2017-02-02 | 2017-02-02 | Forward scatter in particulate matter sensor |
CN201810101456.5A CN108426805B (en) | 2017-02-02 | 2018-02-01 | Forward scattering in particulate matter sensors |
US16/143,438 US10890516B2 (en) | 2017-02-02 | 2018-09-26 | Forward scatter in particulate matter sensor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/423,302 US20180217044A1 (en) | 2017-02-02 | 2017-02-02 | Forward scatter in particulate matter sensor |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/143,438 Continuation US10890516B2 (en) | 2017-02-02 | 2018-09-26 | Forward scatter in particulate matter sensor |
Publications (1)
Publication Number | Publication Date |
---|---|
US20180217044A1 true US20180217044A1 (en) | 2018-08-02 |
Family
ID=62977297
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/423,302 Abandoned US20180217044A1 (en) | 2017-02-02 | 2017-02-02 | Forward scatter in particulate matter sensor |
US16/143,438 Active US10890516B2 (en) | 2017-02-02 | 2018-09-26 | Forward scatter in particulate matter sensor |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/143,438 Active US10890516B2 (en) | 2017-02-02 | 2018-09-26 | Forward scatter in particulate matter sensor |
Country Status (2)
Country | Link |
---|---|
US (2) | US20180217044A1 (en) |
CN (1) | CN108426805B (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20190178783A1 (en) * | 2017-12-11 | 2019-06-13 | Honeywell International Inc. | Micro airflow generator for miniature particulate matter sensor module |
US20190178775A1 (en) * | 2017-12-11 | 2019-06-13 | Honeywell International Inc. | Miniature optical particulate matter sensor module |
WO2020038593A1 (en) * | 2018-08-21 | 2020-02-27 | Ams Ag | Particulate matter sensor |
EP3819628A1 (en) | 2019-11-05 | 2021-05-12 | Nederlandse Organisatie voor toegepast- natuurwetenschappelijk Onderzoek TNO | In-line identification of aerosol particles |
CN114324095A (en) * | 2021-12-30 | 2022-04-12 | 中国石油大学(北京) | Monitoring device for concentration of particle impurities in gas pipeline |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN115629025A (en) * | 2017-02-06 | 2023-01-20 | 霍尼韦尔国际公司 | Particulate matter sensor with novel turnover mechanism for forming air flow |
KR102598425B1 (en) * | 2018-09-20 | 2023-11-06 | 현대자동차주식회사 | Sensor assembly for particulate matter |
US11867606B1 (en) * | 2020-05-04 | 2024-01-09 | Crs Industries, Inc. | Air quality sensor system |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3835315A (en) * | 1972-12-06 | 1974-09-10 | Us Commerce | System for determining parameters of a particle by radiant energy scattering techniques |
US4175865A (en) * | 1976-04-05 | 1979-11-27 | Cerberus Ag | Smoke detector |
US4636075A (en) * | 1984-08-22 | 1987-01-13 | Particle Measuring Systems, Inc. | Particle measurement utilizing orthogonally polarized components of a laser beam |
US4914310A (en) * | 1988-02-22 | 1990-04-03 | Bonnier Technology Group, Inc. | Method and apparatus for measuring particle concentration in a suspension |
US5461476A (en) * | 1992-11-30 | 1995-10-24 | Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National Defence | Optical apparatus for receiving scattered light |
US6606157B1 (en) * | 1996-09-14 | 2003-08-12 | University Of Hertfordshire | Detection of hazardous airborne fibres |
US6798508B2 (en) * | 2002-08-23 | 2004-09-28 | Coulter International Corp. | Fiber optic apparatus for detecting light scatter to differentiate blood cells and the like |
US7111496B1 (en) * | 2004-04-29 | 2006-09-26 | Pedro Lilienfeld | Methods and apparatus for monitoring a mass concentration of particulate matter |
US20100045982A1 (en) * | 2005-11-29 | 2010-02-25 | Nidec Sankyo Corporation | Particle counter and particle counting device having particle counter, and particle counting system and its use method |
Family Cites Families (25)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3248551A (en) * | 1962-10-22 | 1966-04-26 | Joseph C Frommer | Optical arrangement for sensing very small particles |
US4523841A (en) * | 1979-03-15 | 1985-06-18 | Coulter Electronics, Inc. | Radiant energy reradiating flow cell system and method |
SE428972B (en) * | 1979-03-07 | 1983-08-01 | Svenska Utvecklings Ab | DEVICE FOR DETECTING THE EVENT OF FLUATING, SOLID OR LIQUID PARTICLES IN A GAS |
US4606636A (en) * | 1983-10-25 | 1986-08-19 | Universite De Saint-Etienne | Optical apparatus for identifying the individual multiparametric properties of particles or bodies in a continuous flow |
US4739177A (en) | 1985-12-11 | 1988-04-19 | High Yield Technology | Light scattering particle detector for wafer processing equipment |
GB8726305D0 (en) * | 1987-11-10 | 1987-12-16 | Secr Defence | Portable particle analysers |
US5467189A (en) * | 1993-01-22 | 1995-11-14 | Venturedyne, Ltd. | Improved particle sensor and method for assaying a particle |
US5767967A (en) * | 1997-01-02 | 1998-06-16 | Yufa; Aleksandr L. | Method and device for precise counting and measuring the particulates and small bodies |
US6456439B1 (en) * | 1999-07-16 | 2002-09-24 | Michael J. Mandella | Collimator employing an ellipsoidal solid immersion lens |
GB2379977B (en) * | 2001-09-25 | 2005-04-06 | Kidde Plc | High sensitivity particle detection |
US8049888B2 (en) * | 2004-03-01 | 2011-11-01 | Firma Cytecs Gmbh | Device for measuring light emitted by microscopically small particles or biological cells |
CN1249420C (en) * | 2004-05-09 | 2006-04-05 | 中国科学院上海光学精密机械研究所 | Miniature optical sensor of laser dust particle counter |
US7274445B1 (en) * | 2005-03-11 | 2007-09-25 | Kla-Tencor Technologies Corporation | Confocal scatterometer and method for single-sided detection of particles and defects on a transparent wafer or disk |
US7932490B2 (en) * | 2007-08-07 | 2011-04-26 | Tsi, Inc. | Size segregated aerosol mass concentration measurement device |
US8047055B2 (en) * | 2007-08-08 | 2011-11-01 | Tsi, Incorporated | Size segregated aerosol mass concentration measurement with inlet conditioners and multiple detectors |
US8628976B2 (en) * | 2007-12-03 | 2014-01-14 | Azbil BioVigilant, Inc. | Method for the detection of biologic particle contamination |
CN102308196B (en) * | 2008-12-18 | 2014-02-05 | 百维吉伦特系统有限公司 | Compact detector for simultaneous particle size and fluorescence detection |
US7907269B2 (en) * | 2009-07-23 | 2011-03-15 | Kla-Tencor Corporation | Scattered light separation |
DE102011002421A1 (en) * | 2011-01-04 | 2012-07-05 | Robert Bosch Gmbh | Measuring device for measuring particle concentrations by means of scattered light and method for monitoring the measuring device |
US9134230B2 (en) * | 2011-04-06 | 2015-09-15 | Instant Bioscan, Llc | Microbial detection apparatus and method |
WO2013022971A1 (en) * | 2011-08-09 | 2013-02-14 | Tsi, Incorporated | System and method for converting optical diameters of aerosol particles to mobility and aerodynamic diameters |
CN102564928B (en) | 2012-01-09 | 2013-03-27 | 南通大学 | Sensor for optical particle counters |
US8477307B1 (en) * | 2012-01-26 | 2013-07-02 | Ann Rachel Yufa | Methods and apparatus for biomedical agent multi-dimension measuring and analysis |
JP6286863B2 (en) * | 2013-05-09 | 2018-03-07 | ソニー株式会社 | Optical system and terahertz emission microscope |
CN204594848U (en) | 2015-04-20 | 2015-08-26 | 江苏苏净集团有限公司 | A kind of monitoring device of atmosphere particle concentration |
-
2017
- 2017-02-02 US US15/423,302 patent/US20180217044A1/en not_active Abandoned
-
2018
- 2018-02-01 CN CN201810101456.5A patent/CN108426805B/en active Active
- 2018-09-26 US US16/143,438 patent/US10890516B2/en active Active
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3835315A (en) * | 1972-12-06 | 1974-09-10 | Us Commerce | System for determining parameters of a particle by radiant energy scattering techniques |
US4175865A (en) * | 1976-04-05 | 1979-11-27 | Cerberus Ag | Smoke detector |
US4636075A (en) * | 1984-08-22 | 1987-01-13 | Particle Measuring Systems, Inc. | Particle measurement utilizing orthogonally polarized components of a laser beam |
US4914310A (en) * | 1988-02-22 | 1990-04-03 | Bonnier Technology Group, Inc. | Method and apparatus for measuring particle concentration in a suspension |
US5461476A (en) * | 1992-11-30 | 1995-10-24 | Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National Defence | Optical apparatus for receiving scattered light |
US6606157B1 (en) * | 1996-09-14 | 2003-08-12 | University Of Hertfordshire | Detection of hazardous airborne fibres |
US6798508B2 (en) * | 2002-08-23 | 2004-09-28 | Coulter International Corp. | Fiber optic apparatus for detecting light scatter to differentiate blood cells and the like |
US7111496B1 (en) * | 2004-04-29 | 2006-09-26 | Pedro Lilienfeld | Methods and apparatus for monitoring a mass concentration of particulate matter |
US20100045982A1 (en) * | 2005-11-29 | 2010-02-25 | Nidec Sankyo Corporation | Particle counter and particle counting device having particle counter, and particle counting system and its use method |
Non-Patent Citations (3)
Title |
---|
Horvath 4,175,865 * |
Knollenberg 4,636,075 * |
Lilienfeld 7,111,496 * |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11359621B2 (en) * | 2017-12-11 | 2022-06-14 | Honeywell International Inc. | Miniature optical particulate matter sensor module |
US20190178775A1 (en) * | 2017-12-11 | 2019-06-13 | Honeywell International Inc. | Miniature optical particulate matter sensor module |
CN110073196A (en) * | 2017-12-11 | 2019-07-30 | 霍尼韦尔国际公司 | Micro-optical particulate matter sensors module |
US10837891B2 (en) * | 2017-12-11 | 2020-11-17 | Honeywell International Inc. | Miniature optical particulate matter sensor module |
US20190178783A1 (en) * | 2017-12-11 | 2019-06-13 | Honeywell International Inc. | Micro airflow generator for miniature particulate matter sensor module |
US11009447B2 (en) * | 2017-12-11 | 2021-05-18 | Honeywell International Inc. | Micro airflow generator for miniature particulate matter sensor module |
US11808691B2 (en) | 2017-12-11 | 2023-11-07 | Honeywell International Inc. | Micro airflow generator for miniature particulate matter sensor module |
WO2020038593A1 (en) * | 2018-08-21 | 2020-02-27 | Ams Ag | Particulate matter sensor |
CN112585447A (en) * | 2018-08-21 | 2021-03-30 | ams有限公司 | Particulate matter sensor |
US11885726B2 (en) | 2018-08-21 | 2024-01-30 | Ams Ag | Particulate matter sensor |
EP3819628A1 (en) | 2019-11-05 | 2021-05-12 | Nederlandse Organisatie voor toegepast- natuurwetenschappelijk Onderzoek TNO | In-line identification of aerosol particles |
WO2021091374A1 (en) | 2019-11-05 | 2021-05-14 | Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno | In-line identification of aerosol particles |
CN114324095A (en) * | 2021-12-30 | 2022-04-12 | 中国石油大学(北京) | Monitoring device for concentration of particle impurities in gas pipeline |
Also Published As
Publication number | Publication date |
---|---|
US10890516B2 (en) | 2021-01-12 |
CN108426805B (en) | 2022-10-14 |
US20190025180A1 (en) | 2019-01-24 |
CN108426805A (en) | 2018-08-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10890516B2 (en) | Forward scatter in particulate matter sensor | |
US7088447B1 (en) | Particle counter with self-concealing aperture assembly | |
JP6688966B2 (en) | Particle detection sensor | |
KR101905275B1 (en) | Particle sensor and electronic apparatus equipped with the same | |
US20210231555A1 (en) | Micro airflow generator for miniature particulate matter sensor module | |
US7502110B2 (en) | Design for particle sensor system | |
JP2000500867A (en) | Particle sensor with fiber optic cable | |
US20120162644A1 (en) | Microparticle detection apparatus | |
KR101574435B1 (en) | Detection apparatus for micro dust and organism | |
US10119908B2 (en) | Particle sensor | |
KR101825159B1 (en) | Heterogeneous mirror coupled detection apparatus for micro dust and organism adding function of decreasing scatterde reflection of light | |
WO2017090134A1 (en) | Particle sensor | |
KR101878094B1 (en) | Heterogeneous mirror coupled detection apparatus for micro dust and organism | |
JP2017138223A (en) | Minute object detector | |
JP7003258B2 (en) | Particle detector | |
CN102564929A (en) | High-flow dust particle counting sensor with novel photosensitive area structure | |
CA2549615A1 (en) | Coriolis mass flow sensor with optical vibration detectors | |
EP3264065A1 (en) | Particulate matter detector | |
JP4688804B2 (en) | Improved design of particle sensor system | |
CN202471562U (en) | Large-flow dust particle counting sensor with novel photosensitive region structure | |
CN108398363B (en) | Particulate matter sensor with novel turnover mechanism for forming air flow | |
CN109754565A (en) | A kind of photoelectric smoke smoke detection darkroom | |
CN113533144B (en) | Laser particle size analysis device | |
JP2007178149A (en) | Light scattering type particle counter | |
JP2005351714A (en) | Fine particle measuring device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: HONEYWELL INTERNATIONAL INC., A DELWARE CORPORATIO Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:YANG, OUYANG;TIAN, LU;FENG, CHEN;AND OTHERS;SIGNING DATES FROM 20170124 TO 20170131;REEL/FRAME:041162/0309 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |