Miniature air flow generator for a miniature particulate matter sensor module

Abstract

The present invention is entitled "Micro Airflow Generator for Micro Particulate Matter Sensor Module". Embodiments of the present invention generally relate to micro airflow generators that do not use fans or heaters to generate airflow (e.g., in compact optical PM sensors). Rather, embodiments of the present invention can generally use induced motion of a membrane / diaphragm element to generate airflow (where the motion of the membrane in turn causes motion in the air). For example, the membrane or diaphragm element can be driven by an (electronic) actuator element, such as an electromagnetic actuator or a piezoelectric disc bender (or some other means of vibrating / moving the membrane element in a manner that causes airflow). In some embodiments, the electromagnetic actuator itself can include a membrane that can serve as the membrane / diaphragm element and the electronic actuator element (such that the electromagnetic actuator can encompass the membrane element and the electronic actuator element, such as a magnet and a corresponding coil) and / or a piezoelectric disc bender.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201811512150.5, filed on December 11, 2018, entitled “Miniature Airflow Generator for Miniature Particulate Matter Sensor Module”. BACKGROUND

[0002] Compact / micro optical particulate matter (PM) sensors typically use a fan to generate airflow for optical scattering particle detection. However, such fans are bulky, noisy, unstable, and have a limited lifetime. Heaters have also been used as a replacement for fans to generate airflow. However, heaters have lower efficiency and lower flow rates, while also having higher power consumption. And while conventional pumps can be used with large optical PM sensors (e.g., at least 10 times larger in size than compact optical PM sensors) to generate a stable airflow, such pumps tend to be too large and power consuming to work effectively when used with compact optical PM sensors. Thus, there is a need for a new device for generating an airflow for use with compact optical PM sensors, e.g., for optical scattering particle detection. SUMMARY

[0003] In some embodiments, a miniature airflow generator can include a pump housing, a diffusion channel incorporated into the pump housing, a valve conduit incorporated into the pump housing and in fluid communication with the diffusion channel, a pump plate configured to fit within the pump housing and including an orifice in fluid communication with the valve conduit, an actuator positioned adjacent to the pump plate within the pump housing, and a steel cover plate configured to attach to the pump housing and contain elements within the pump housing.

[0004] In some embodiments, a method for generating an airflow via a miniature airflow generator within a compact optical scattering particulate matter sensor can include providing a miniature airflow generator, generating an airflow out of a housing via an actuator, directing the airflow into an optical scattering particle detection module, and detecting particulate matter within the airflow by the optical scattering particle detection module. The miniature airflow generator includes a housing having at least one inlet and at least one outlet, a membrane configured such that movement of the membrane drives air through the outlet, and an actuator configured to drive movement of the membrane.

[0005] In some embodiments, a compact optical scattering particulate matter sensor includes a miniature airflow generator including a housing having an inlet and an outlet, a membrane configured such that movement of the membrane drives air through the outlet, and an actuator configured to drive movement of the membrane, and an optical scattering particle detection module, wherein the outlet of the miniature airflow generator is configured to direct an airflow to interact with the optical scattering particle detection module. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 An exploded view of an exemplary micro-gas flow generator including an electromagnetic actuator according to embodiments of the present disclosure is shown.

[0007] Figure 2A is a top perspective view of a fully assembled micro-gas flow generator according to embodiments of the present disclosure.

[0008] Figure 2B is a bottom perspective view of a fully assembled micro-gas flow generator according to embodiments of the present disclosure.

[0009] Figure 2C is a top perspective view of a fully assembled micro-gas flow generator according to embodiments of the present disclosure.

[0010] Figure 2D is a side view of a fully assembled micro-gas flow generator according to embodiments of the present disclosure.

[0011] Figure 2E is a cross-sectional view of a micro-gas flow generator according to embodiments of the present disclosure.

[0012] Figure 3 An exploded view of another exemplary micro-gas flow generator including a piezoelectric disc bender according to embodiments of the present disclosure is shown.

[0013] Figure 4A is a cross-sectional view of a micro-gas flow generator showing air intake according to embodiments of the present disclosure.

[0014] Figure 4B is another cross-sectional view of a micro-gas flow generator showing air output according to embodiments of the present disclosure.

[0015] Figure 5A A top exploded view of an exemplary compact optical PM sensor including an exemplary micro-gas flow generator according to embodiments of the present disclosure is shown.

[0016] Figure 5B A bottom exploded view of an exemplary compact optical PM sensor including an exemplary micro-gas flow generator according to embodiments of the present disclosure is shown.

[0017] Figure 5C is a fully assembled view of a compact optical PM sensor according to embodiments of the present disclosure.

[0018] Figure 5D is a cross-sectional view of a compact optical PM sensor according to embodiments of the present disclosure.

[0019] Figure 6Ais a top view of a compact optical PM sensor plate assembly according to embodiments of the present disclosure, showing laser light scattering particle detection.

[0020] Figure 6B is a three-dimensional perspective view of a compact optical PM sensor plate assembly according to embodiments of the present disclosure. DETAILED DESCRIPTION

[0021] It should be understood at the outset that although illustrative implementation(s) will be described below with reference to one or more exemplary embodiments, the disclosed system and method can be implemented with any number of techniques capable of such implementation, either currently existing or in existence at the time of application. The disclosure should in no way be limited to the illustrative implementation(s) set forth below, but can include any number of additional or alternative steps, techniques, components, and / or forms within the scope of the disclosure.

[0022] The following brief definitions of terms should apply throughout the application:

[0023] The term “comprising” means including, but not limited to, and should be interpreted in the manner set out in the decision of the Enlarged Board of Appeal of 4.3.03;

[0024] The phrases “in one embodiment,” “according to one embodiment,” etc., as may occur in the specification, is not necessarily limiting, as these phrases can refer to one embodiment, or alternatively, can refer to different embodiments of the application, that describe only one feature, structure, or characteristic of the application. Further, each of the phrases “in one embodiment” of the application or “in one embodiment of the application” as can occur in the specification, is not necessarily referring to one particular embodiment, or alternative embodiment (in the sense of alternatives excluding each other) of the application, but can include the whole disclosure of the application, which will become apparent after reading this specification but before claiming patent priority for this application, unless it is specified otherwise.

[0025] If the specification states a component, feature, structure, or characteristic “may” be included, or “might” have a property, then it is open ended in the sense that the component, feature, structure, or characteristic can or might be included in some embodiments, but not necessarily in others, unless the context clearly directs otherwise.

[0026] Those skilled in the art will appreciate that the term “about” or “approximately,” when used in connection with a number or a numerical value, can mean the specific number or alternatively can mean a range of numbers (e.g., + / - 10%) around the specific number; and

[0027] If the specification states a component or feature “can,” “might,” or “may” be included or be associated with another component or feature, that particular component or feature is not required to be included or associated with another component or feature. Some embodiments can include a component or feature while others can not. Inclusion of a component or feature is optional, unless otherwise indicated.

[0028] The disclosed embodiments generally relate to micro air flow generators that do not use fans or heaters to generate air flow (e.g., in compact optical PM sensors). Rather, the disclosed embodiments can generally use induced motion of a membrane / diaphragm element to generate air flow (where the motion of the membrane in turn causes motion in the air). For example, the membrane or diaphragm element can be driven by an (electronic) actuator element, such as an electromagnetic actuator or a piezoelectric disc bender (or some other device that vibrates / moves the membrane element in a manner that causes air flow). In some embodiments, the electromagnetic actuator itself can include a membrane that can function as the membrane / diaphragm element and the electronic actuator element (such that the electromagnetic actuator can encompass the membrane element and the electronic actuator element, such as a magnet and a corresponding coil) and / or a piezoelectric disc bender. In some embodiments, such micro air flow generators can be referred to as micro membrane pumps or micro pumps, and any such micro pump can be used to obtain the desired air flow. Generally, a micro pump can include a pump diaphragm (such as a membrane element) and an actuator / driver (e.g., a device that causes corresponding motion of the membrane) that is configured to cause motion of the membrane element. Generally, micro air flow generators used with compact optical PM sensors can provide an outlet air flow rate in the range of 0.1 to 1 L / min. And generally, such micro air flow generators can have a power consumption of 200 mW or less (e.g., in the range of 100 to 200 mW), and / or a maximum noise generated by the micro air flow generator of 20 dB or less (e.g., in the range of 10 to 20 dB). And to be effectively used in compact optical PM sensors, such micro air flow generators can generally have a footprint of 100 mm 2 or less and / or a volume of 250 mm 3 or less.

[0029] Accordingly, some embodiments of the present disclosure can include micro air flow generators in which the air flow is generated by an electromagnetic actuator (e.g., which in some embodiments can drive a corresponding membrane). In some such embodiments, the electromagnetic actuator can be constructed from a micro vinyl speaker component or other similar material. In one embodiment, the electromagnetic actuator can also operate as a pump diaphragm (e.g., as a pump diaphragm / membrane and an actuator / driver to cause motion). In some embodiments, a micro air flow generator with an electromagnetic actuator can have a diameter of 10 mm and a thickness of 2.5 mm.

[0030] Alternatively, embodiments of the present disclosure can include a micro air flow generator in which air flow is generated by a piezoelectric disc bender actuator (e.g., which can drive a corresponding membrane in some embodiments). The piezoelectric disc bender actuator can be made of a piezoelectric buzzer disc bender component or similar material. In one embodiment, the piezoelectric disc bender actuator can also operate as a pump diaphragm (e.g., as a pump diaphragm / membrane as well as an actuator / driver). In some embodiments, the micro air flow generator with piezoelectric actuator can have a diameter of 10 mm and a thickness of 2.5 mm.

[0031] Some disclosed embodiments can include a micro air flow generator having fixed passive dynamic check valves implemented on the inlet and outlet. Thus, the size of the air flow generator can be reduced and the structure can be simplified. Thus, the overall reliability of the air flow generator can be improved compared to existing pumps.

[0032] Some embodiments of the present disclosure can include the use of ultrasonic frequency waves to prevent audible noise and to prevent dust buildup during operation of the micro air flow generator. For example, the membrane / diaphragm element can be driven by the actuator / driver at a rate corresponding to an ultrasonic frequency. The micro air flow generator can include a injection molded pump housing and, in some embodiments, the pump housing can include one or more Tesla valve conduits as inlet check valves and / or a diffusion channel as an outlet check valve. In some embodiments, the micro air flow generator can include a Venturi tube in the neck of the tube at the outlet for providing low pressure suction from the inlet. And in some embodiments, the micro air flow generator can include a pump plate in the pump housing to form the diffusion channel, one or more valve conduits, and the Venturi tube.

[0033] In implementation, such micro air flow generator embodiments can be used to generate air flow within a compact optical PM sensor. Embodiments are typically about 100 mm 2 or less footprint, 250 mm 3 in volume, and / or 10 mm or less in diameter, enabling them to fit within a compact optical PM sensor, which is typically less than 500 mm 3 in size. In a typical disclosed embodiment of a compact optical PM sensor, the micro air flow generator will be positioned / oriented / constructed to generate air flow of a sample air flow (e.g., from an external environment to be tested) for optical scattering particle detection. Thus, the micro air flow generator can draw or drive the (sample) air flow through the optical scattering PM detector unit (e.g., through the light beam and / or between the light source and the light detector for optical scattering particle detection).

[0034] The disclosed micro flow generator embodiments operate with compact optical PM sensors that use a simplified laser light source with a very short detection distance. The disclosed embodiments describe a light source with a very small laser beam size (e.g., 2 pm at a nominal wavelength of 650 nm), the scattered laser beam comprising a direct diode laser beam that typically does not use any optical elements such as optical windows and / or focusing optics. The laser diode die can have a well-defined output beam profile at the near field close to the diode output area. The initial diode laser beam is typically used without optical shaping of the beam profile. The disclosed embodiments also describe a photodiode for collecting the scattered laser light that is typically used without any collection optics. In some embodiments, the short collection distance means that the photodiode can efficiently collect the scattered laser light. The high efficiency ensures that enough particulate matter should be detected and counted for the sensor to work properly even with such small size and without using focusing optics. In other embodiments, there can be an optical trap to collect stray scattered light and minimize stray light into the detection area, and there can be a laser heat sink that can provide thermal management for the laser diode die.

[0035] Figure 1 An exploded view of an exemplary micro flow generator 100 using an electromagnetic actuator 102 is shown. Figure 1 The electromagnetic actuator 102 in the micro flow generator 100 can include a membrane 104 with a coil 105 and a magnet 106 that can act as an actuator / driver element to drive the membrane 104. In some embodiments, the electromagnetic actuator 102 can be constructed from a micro vinyl speaker component or other similar material. The electromagnetic actuator 102 is typically enclosed in a (pump) housing 108 (which typically has an outlet) between a (pump) plate 110 and a (steel) cover plate 112. In some embodiments, the electromagnetic actuator 102 can be constructed from a micro vinyl speaker component or other similar material. Figure 1 In the micro flow generator 100, the pump plate 110 has an orifice that is aligned (e.g., along a longitudinal axis) with the outlet of the pump housing 108, and the pump housing 108 contains a Tesla valve conduit 114 that is in fluid communication with the inlet and outlet (and typically the orifice in the pump plate 110). The size of the orifice in the pump plate 110 is typically in the range of about 0.3 mm Figure 1 In some embodiments, the size of the orifice in the pump plate 110 is in the range of about 0.3 mm 2 (e.g., in the range of 0.2 to 0.5 mm 2 and / or 0.7 mm 2 .

[0036] Figures 2A-2E Various views of the micro flow generator 100 fully assembled with an electromagnetic actuator 102 as shown in Figure 1 Various views of the micro flow generator 100 fully assembled with an electromagnetic actuator 102 as shown in Figure 2A A top side (or housing 108) of the micro flow generator 100 is shown,Figure 2B The back side (or cover plate 112) of the micro flow generator 100 is shown. In Figure 2A the flow generator 100 includes one or more electrical terminals 204 (shown on one or more corners of the housing 108) that can provide power and / or operate / drive the electromagnetic actuator 102. Air intake can occur through one or more air inlets 206 (e.g., typically located at one or more corners of the housing, e.g., at corners that do not have electrical terminals 204) and / or from air inlets 208 of the cover plate 112. Air can be expelled from the flow generator 100 through air outlet 210. Thus, for example, in operation, air can be drawn into the housing 108 via the inlets (e.g., 208 and / or 206), e.g., a vacuum is created by the movement / vibration / pulsation of the membrane of the electromagnetic actuator 102 as air is expelled through the outlet 210. Once air is drawn into the housing 108, movement of the membrane can drive air out of the housing 108 through the outlet 210. When such micro flow generators 100 are used in compact optical PM sensors, the outlet 210 is typically positioned such that it is configured to provide a sample flow for testing by optical scatter particle detection (e.g., such that the air flow from the outlet 210 interacts with the optical scatter detection unit, e.g., passes between a light source and a light detector). Figure 2A

[0037] Figure 2C and Figure 2D Dimensions of the flow generator 100 in one embodiment are shown. In Figure 2C each side 212 and 213 of the flow generator 100 is about 10 mm. In Figure 2D the height or thickness 214 of the flow generator 100 is about 2.5 mm. Typically, the footprint of the flow generator 100 can be 100 mm 2 or less (e.g., 75-100 mm 2 , 85-100 mm 2 , or 75-85 mm 2 ), and / or the three-dimensional (volume) dimensions can be 250 mm 3 or less (e.g., 100-250 mm 3 , or 150-250 mm 3 , or 100-150 mm 3 ).

[0038] Figure 2E Dimensions of the flow generator 100 in one embodiment are shown. In Figure 1 ​a cross-sectional view of the microfluidic air generator 100. In this view, the shape of the outlet 210 (e.g., wider at the distal end / location than at the proximal end / location relative to the membrane) as a diffusion channel in this embodiment can be seen, as well as the relative positions of the valve conduit 114 relative to the electromagnetic actuator / membrane 104, the orifice in the pump plate 110, and the outlet 210. The outlet 210 generally has Figure 2E about 0.4 mm 2 about 1 mm 2 about 1.2 mm. Thus, movement of the membrane 104 of the electromagnetic actuator (e.g., in response to an electrical signal from the electrical terminals 204) draws air in from the one or more inlets 206, through the Tesla valve conduit 114, and out of the outlet 210. Additionally, a venturi neck can be used to provide low pressure to help draw air into the inlets. This configuration for a microfluidic air generator can effectively direct air (thereby improving stability) without moving parts. For example, the diffusion channel (at the outlet 210) can reduce pressure to help flow out through the outlet, while the Tesla valve conduit 114 can provide high friction to reduce flow back into the inlet (so that air driven by membrane motion can be directed out through the outlet without significant loss back into the inlet even without an active part valve).

[0039] Figure 3 is an exploded view of an exemplary microfluidic air generator 300 using a piezoelectric disc bender actuator 302. The piezoelectric disc bender actuator 302 can be constructed of piezoelectric buzzer disc bender components or similar materials. Figure 3 The piezoelectric disc bender actuator 302 is generally enclosed in a pump housing 304 between a pump plate 306 and a cover plate 308 (similar to the discussion above). The pump housing 304 can include a Tesla valve conduit 314 in fluid communication with the inlets and outlets (and generally orifices in the pump plate 306).

[0040] Figures 4A-4B shows the microfluidic air generator 300 in operation using the piezoelectric disc bender actuator 302. Figure 3 is a cross-sectional view of the microfluidic air generator 300. The arrows in each view generally indicate the direction of air flow through the air generator. In Figure 4A , air flows into the microfluidic air generator 300 (e.g., through the inlets and Tesla valve conduit 314 and down through the orifice in the pump plate 306 towards the membrane 302) as the piezoelectric disc bender actuator 302 can be seen bending / flexing downward. In Figure 4BIn the middle, air flows out of the pump 300 and out of the outlet / diffuser channel 404. It can be seen that the piezoelectric disc bender actuator 302 is bent upwards (as it is the motion of the piezoelectric disc bender, which drives air to flow upwards from the piezoelectric disc towards and through the outlet with diffuser channel). In Figure 4B In the middle, the diffuser channel 404 contains a venturi 408 at the neck (in other words, the width narrows, which creates low pressure to draw air into the inlet). Also, the large friction of the valve conduit 314 can help to reduce the flow to the inlet, directing air to flow out of the diffuser channel 404.

[0041] Figures 5A-5D Various views of an exemplary micro air flow generator 300 used in a compact optical PM sensor 500 are shown. Figure 5A and Figure 5B Top and bottom exploded views of an exemplary compact optical PM sensor 500 including an exemplary micro air flow generator 300 are shown, respectively. The compact optical PM sensor 500 can include the micro air flow generator 300, a sensor cover 502, and an optical scatter particle detection module (which can also include a compact PM sensor board assembly) 504. Figure 5C An assembly view of such a compact optical PM sensor 500 is shown. In Figure 5D In the middle, a cross-sectional view of the compact optical PM sensor 500 can be seen, with the laser source 510 (e.g., laser diode die) identified. The orifices / openings / holes (e.g., air flow openings) of the various elements are typically aligned, for example, along the central axis of the device. Typically, air will travel in direction 512 through the compact optical PM sensor 500.

[0042] Turning now to Figures 6A-6B , these drawings show Figure 5A an exemplary optical scatter particle detection module (which can also include a compact PM sensor board assembly) 504 shown in Figure 6A In the middle, the particle detection module 504 can include a printed circuit board 600, a laser diode die 612, a photodiode 608, a laser heat sink 602, a laser beam trap 604, a low noise preamplifier 606, an output beam hole 614, and / or a processor 610. Figure 6B A perspective three-dimensional view of the particle detection module 504 seen in Figure 6A In the middle, the particle detection module 504 can include a printed circuit board 600, a laser diode die 612, a photodiode 608, a laser heat sink 602, a laser beam trap 604, a low noise preamplifier 606, an output beam hole 614, and / or a processor 610.2 or less, and / or a three-dimensional (volume) dimension can be 0.0075 mm 3 or less. The laser diode die 612 typically does not have associated optical components, such as optical windows or focusing optics, which are bulky and take up a lot of space on the sensor board. Thus, the beam from the laser diode die 612 can be used without optically shaping the beam profile.

[0043] For example, in operation, the laser diode die 612 will emit a well-defined output beam profile (e.g., with a fixed beam divergence) in the near field close to the output region of the laser diode die 612. The output beam or aperture 614 (of the laser diode die 612) is emitted in a path that intersects the air flow path. In other words, air flows in a direction through the particle detection module 504 (which has an opening / aperture / orifice positioned centrally and configured to receive the air output stream from the micro air flow generator). For example, air flows through the aperture 614 in the center of the particle detection module 504, through the output beam in the aperture 614, and then exits the particle detection module 504 (as if perpendicular to the page). Particles can scatter in any direction as they pass through the wide output beam. Any particles that scatter and are deflected in a direction toward the photodiode 608 will be detected and measured by the photodiode 608 (which can be oriented perpendicular to the beam). Any particles that scatter in any other direction should be captured by the laser beam trap 604. The laser beam trap 604 can also be configured to dump the laser beam to minimize stray light into the detection region. The laser heat sink 602 is typically configured to provide thermal management for the laser diode die 612. Figure 6A For example, in operation, the laser diode die 612 will emit a well-defined output beam profile (e.g., with a fixed beam divergence) in the near field close to the output region of the laser diode die 612. The output beam or aperture 614 (of the laser diode die 612) is emitted in a path that intersects the air flow path. In other words, air flows in a direction through the particle detection module 504 (which has an opening / aperture / orifice positioned centrally and configured to receive the air output stream from the micro air flow generator). For example, air flows through the aperture 614 in the center of the particle detection module 504, through the output beam in the aperture 614, and then exits the particle detection module 504 (as if perpendicular to the page). Particles can scatter in any direction as they pass through the wide output beam. Any particles that scatter and are deflected in a direction toward the photodiode 608 will be detected and measured by the photodiode 608 (which can be oriented perpendicular to the beam). Any particles that scatter in any other direction should be captured by the laser beam trap 604. The laser beam trap 604 can also be configured to dump the laser beam to minimize stray light into the detection region. The laser heat sink 602 is typically configured to provide thermal management for the laser diode die 612.

[0044] In some embodiments, the photodiode 608 is a silicon pin photodiode that is approximately 2 mm long, 1.25 mm wide, and 0.85 mm high. The footprint of the photodiode 608 can be 2.5 mm 2 or less, and / or a three-dimensional (volume) dimension can be 2.125 mm 3 or less. Similar to the laser diode die 612, the photodiode 608 can be used without any collection optics or other optics. In one embodiment, the distance between the output beam 614 and the photodiode 608 is a short / near distance of approximately 1.5 mm. This short (near) distance at which the photodiode can collect and detect particulate matter for analysis enables the micro-laser and photodiode to function as a PM sensor accurately and reliably (e.g., even without optics). The short distance allows the photodiode 608 to operate efficiently in collecting and detecting PM scattered by the output beam.

[0045] In some embodiments, the processor 610 and / or circuitry can include a driver for the laser diode die 612 and a signal processor for analyzing the scattered particle signals gathered and detected by the photodiode 608. The processor and / or circuitry can also include a low noise preamplifier for the photodiode.

[0046] Having described various devices and methods herein, exemplary embodiments or aspects can include, but are not limited to:

[0047] In a first embodiment, a micro air flow generator can include a pump housing, a diffusion channel incorporated into the pump housing, a valve conduit incorporated into the pump housing and in fluid communication with the diffusion channel, a pump plate configured to fit within the pump housing and including an orifice in fluid communication with the valve conduit, an actuator positioned adjacent to the pump plate within the pump housing, and a steel cover plate configured to attach to the pump housing and contain elements within the pump housing.

[0048] A second embodiment can include the micro air flow generator of the first embodiment, wherein the actuator is an electromagnetic actuator.

[0049] A third embodiment can include the micro air flow generator of the second embodiment, wherein the electromagnetic actuator includes a magnet and a membrane having a coil.

[0050] A fourth embodiment can include the micro air flow generator of any of the first through third embodiments, wherein the actuator is a piezoelectric disc bender.

[0051] A fifth embodiment can include the micro air flow generator of any of the first through fourth embodiments, wherein the actuator is configured to generate an air flow into and out of the housing via one or more air inlets and one or more air outlets of the micro air flow generator.

[0052] A sixth embodiment can include the micro air flow generator of the fifth embodiment, wherein the air inlets and air outlets include dynamic check valves.

[0053] A seventh embodiment can include the micro air flow generator of any of the first through sixth embodiments, wherein the diffusion channel has a venturi shape.

[0054] An eighth embodiment can include the micro air flow generator of any of the first through seventh embodiments, wherein a fully assembled pump has a diameter of about 10 mm.

[0055] A ninth embodiment can include the micro air flow generator of any of the first through eighth embodiments, wherein a fully assembled pump has a height of about 2.5 mm.

[0056] The tenth embodiment can include the micro-gas flow generator of any of the first through ninth embodiments, further comprising a membrane, wherein the actuator drives the membrane, the membrane configured to generate a gas flow from an outlet in the pump housing.

[0057] In an eleventh embodiment, a method for generating a gas flow via a micro-gas flow generator within a compact optical scattering particulate matter sensor can include providing a micro-gas flow generator; generating a gas flow from a housing by an actuator; directing the gas flow into an optical scattering particle detection module; and detecting particulate matter within the gas flow by the optical scattering particle detection module. The micro-gas flow generator includes a housing having at least one inlet and at least one outlet, a membrane configured such that movement of the membrane drives air through the outlet, and an actuator configured to drive movement of the membrane.

[0058] The twelfth embodiment can include the method of the eleventh embodiment, wherein directing the gas flow into the optical scattering particle detection module includes passing the gas flow between a light source and a light detector.

[0059] The thirteenth embodiment can include the method of the eleventh or twelfth embodiment, further comprising generating a laser beam by a laser diode die of the optical scattering particle detection module; and detecting light scattered by particulate matter passing through the laser beam by a photodiode.

[0060] The fourteenth embodiment can include the method of any of the eleventh through thirteenth embodiments, further comprising applying a force to the actuator, thereby causing movement of the membrane.

[0061] The fifteenth embodiment can include the method of any of the eleventh through fourteenth embodiments, further comprising directing the gas flow through a valvular conduit of the housing prior to the air passing through the outlet of the housing.

[0062] In a sixteenth embodiment, a compact optical scattering particulate matter sensor includes a micro-gas flow generator including a housing having an inlet and an outlet, a membrane configured such that movement of the membrane drives air through the outlet, and an actuator configured to drive movement of the membrane; and an optical scattering particle detection module, wherein the outlet of the micro-gas flow generator is configured to direct a gas flow to interact with the optical scattering particle detection module.

[0063] The seventeenth embodiment can include the compact optical scattering particulate matter sensor of the sixteenth embodiment, wherein the compact sensor has a size of 500 mm 3 or less.

[0064] The eighteenth embodiment can include the compact optical scattering particulate matter sensor of the sixteenth or seventeenth embodiment, wherein the micro-gas flow generator has a footprint of 100 mm2 or less.

[0065] The nineteenth implementation can include the compact optical scattering particulate matter sensor of any of the sixteenth through eighteenth implementations, wherein the micro air flow generator has a volume of 250 mm 3 or less.

[0066] The twentieth implementation can include the compact optical scattering particulate matter sensor of any of the sixteenth through nineteenth implementations, wherein the optical scattering particle detection module is configured to detect particulate matter within an air flow generated by the air flow generator.

[0067] While various embodiments according to the principles disclosed herein have been shown and described herein, it is understood that modifications, combinations, sub-combinations, and alternatives can occur to persons skilled in the art upon reading this disclosure. The embodiments described herein are only representative of the many possible embodiments that fall within the scope of the present disclosure. Numerous variations, combinations, and modifications are possible and are within the scope of the disclosure. Alternative implementations of the embodiments of the disclosure incorporating one or more of the variations, combinations and modifications are within the scope of the disclosure. Accordingly, the scope of protection is not limited by the description set out above, but is given by the claims that follow, and any equivalents thereof. Each claim is incorporated into the specification as further disclosure. The claims are thus to be afforded all the benefits of the disclosure that is presented throughout this specification. In addition, any combination of the recited claims can be used to define alternative implementations of the disclosure.

[0068] Furthermore, the section headings given herein are for organizational purposes only and are not meant to be used as limiting in interpreting the claims. The disclosure is presented throughout this application in terms of implementations. Thus, various implementations of the disclosure have been described for the purposes of exemplification and disclosure, and as illustrative applications of the various implementations of the disclosure. However, it is to be understood that various other modifications and implementations can be made without departing from the scope or spirit of the disclosure and that other applications come within the scope of the following claims.

[0069] In particular and as an example, while the heading might refer to a "Technical Field", the claims should not be limited to the specific technical fields with which that heading is associated. Also, any prior art publication's description example implementation or configuration should not be interpreted as an acknowledgement that such prior art is considered well known to those skilled in the art. The claims should therefore not be limited to the preferred implementations and configurations disclosed herein. Furthermore, references made to "background art" throughout this disclosure are not to be construed as an admission that such art is prior art to any of the applications disclosed herein. The content of this disclosure is to be considered as indicative of only the features that are disclosed explicitly or implicitly in this specification and no further. Furthermore, any reference to "invention" throughout this disclosure is to be construed as referring to the applications disclosed in the claims following this specification, in their most general form, and not to any specific embodiment of these applications.

[0070] The use of broader terms such as “comprising,” “including,” and “having” should be understood to support narrower terms such as “consisting of,” “substantially constituted of,” and “largely composed of.” The use of terms such as “optionally,” “may,” “possibly,” and “possibly” in relation to any element indicates that the element is either unnecessary or necessary, and both alternatives are within the scope of the implementation. Furthermore, references to examples are provided for illustrative purposes only and are not intended to be exclusive.

[0071] While several embodiments have been provided in this disclosure, it should be understood that the disclosed systems and methods may be implemented in many other specific forms without departing from the spirit or scope of this disclosure. This example is intended to be illustrative rather than restrictive and is not intended to be limited to the details given herein. For example, various elements or components may be combined or integrated into another system, or certain features may be omitted or not implemented.

[0072] Furthermore, without departing from the scope of this disclosure, the technologies, systems, subsystems, and methods described and illustrated as discrete or separate in the various embodiments may be combined or integrated with other systems, modules, technologies, or methods. Other items illustrated or discussed as directly coupled or communicating with each other may be indirectly coupled or communicating (whether electrically, mechanically, or otherwise) through some interface, device, or intermediate component. Other examples of changes, substitutions, and modifications can be identified by those skilled in the art, and such changes, substitutions, and modifications can be made without departing from the spirit and scope of this disclosure.

Claims

1. A compact optical scattering particulate matter sensor (500) comprising: A micro air flow generator (100) comprising: a pump housing (108) having an outlet, an inner surface, and an opposite outer surface; a diffusion channel (210) incorporated into the pump housing (108) and located at the outlet; a membrane (104) configured such that movement of the membrane drives air through the outlet; an actuator (102) configured to drive movement of the membrane at a rate corresponding to an ultrasonic frequency; and an optical scattering particle detection module (504), wherein the outlet of the micro air flow generator (100) is configured to direct an air flow to interact with the optical scattering particle detection module (504).

2. The compact optical scattered-particle sensor (500) according to claim 1, wherein The micro air flow generator (100) further comprises: a valve conduit (114) incorporated into the pump housing (108) and in fluid communication with the diffusion channel (210); a pump plate (110) configured to fit within the pump housing (108) and comprising an orifice in fluid communication with the valve conduit (114), the orifice being axially aligned with a longitudinal axis of the outlet of the pump housing; the actuator (102) is positioned adjacent to the pump plate within the housing; a steel cover plate (112) configured to be attached to the housing and containing elements of the housing.

3. The compact optical scattered-particle sensor (500) according to claim 2, wherein The actuator (102) is at least one of an electromagnetic actuator and a piezoelectric disc bender, and wherein the electromagnetic actuator comprises a magnet and a membrane having a coil.

4. The compact optical scattered-particle sensor (500) according to claim 1, wherein The actuator (102) is configured to generate an air flow into and out of the housing (108) via one or more air inlets and one or more air outlets of the micro air flow generator (100).

5. The compact optical scattered-particle sensor (500) according to claim 1, wherein The compact optical scattering particulate matter sensor has a size of 500 mm 3 or less.

6. The compact optical scattered-particle sensor (500) of claim 1, wherein, The micro air flow generator (100) has a footprint of 100 mm 2 or less.

7. The compact optical scattered-particle sensor (500) according to claim 1, wherein The diffusion channel (210) has a venturi shape.

8. The compact optical scattered-particle sensor (500) according to claim 1, wherein A fully assembled micro air flow generator has a diameter of about 10 mm.

9. The compact optical scattered-particle sensor (500) of claim 1, wherein, The optical scattering particle detection module is configured to detect particulate matter within the air flow generated by the micro air flow generator.

10. The compact optical scattered-particle sensor (500) of claim 1, wherein, A fully assembled micro air flow generator (100) has a height of about 2.5 mm.

11. The compact optical scattered-particle sensor of claim 1, wherein, The micro air flow generator has a volume of 250 mm 3 or less.

12. The compact optical scattered-particle sensor of claim 4, wherein, The air inlets and air outlets comprise dynamic check valves.

13. A method for generating an air flow via a micro air flow generator within a compact optical scattering particulate matter sensor, the method comprising: providing a micro air flow generator, the micro air flow generator comprising: a pump housing having an outlet, an inner surface, and an opposite outer surface; a diffusion channel incorporated into the pump housing and located at the outlet; a membrane configured such that movement of the membrane drives air through the outlet; and an actuator configured to drive movement of the membrane at a rate corresponding to an ultrasonic frequency; generating an air flow out of the pump housing by the actuator; directing the air flow into an optical scattering particle detection module; and detecting particulate matter within the air flow by the optical scattering particle detection module.

14. The method of claim 13, wherein, Directing the air flow into the optical scattering particle detection module comprises passing the air flow between a light source and a light detector.

15. The method of claim 13, further comprising generating a laser beam by a laser diode die of the optical scattering particle detection module; and detecting light scattered by particulate matter passing through the laser beam by a photodiode.

16. The method of claim 13, further comprising applying a force to the actuator, thereby causing movement of the membrane.

17. The method of claim 13, further comprising directing the air stream through a valve conduit of the housing prior to the air passing through an outlet of the housing.

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