PARTICLE MATTER ANALYSIS DEVICE, ANALYSIS METHOD AND MANUFACTURING METHOD THEREOF
20210109005 · 2021-04-15
Assignee
Inventors
Cpc classification
B03C3/12
PERFORMING OPERATIONS; TRANSPORTING
B03C3/47
PERFORMING OPERATIONS; TRANSPORTING
B03C3/38
PERFORMING OPERATIONS; TRANSPORTING
International classification
B03C3/38
PERFORMING OPERATIONS; TRANSPORTING
B03C3/47
PERFORMING OPERATIONS; TRANSPORTING
C25D5/00
CHEMISTRY; METALLURGY
C25D5/10
CHEMISTRY; METALLURGY
Abstract
A particle matter analysis device, an analysis method and a manufacturing method are disclosed. The particle matter analysis device includes a charger configured to receive power from a power supply device and to charge particles included in intaken air, an electrophoretic mobility particle collector configured to collect particles having electrophoretic mobility greater than a predetermined electrophoretic mobility among the charged particles based on an electrophoretic mobility and to measure a current of electrophoretic mobility particles, an aerodynamic particle collector configured to collect charged particles passing through the electrophoretic mobility particle collector based on an inertial force of the charged particles and to measure a current of aerodynamic particles, a filter configured to collect charged particles passing through the aerodynamic particle collector and to measure a current of filtered particles, and a processor, wherein the processor calculates a density of the particles based on a ratio of the current of electrophoretic mobility particles, the current of aerodynamic particles, and the current of filtered particles.
Claims
1. A particle matter analysis device comprising: a charger configured to receive power from a power supply device and to charge particles included in intaken air; an electrophoretic mobility particle collector configured to collect particles having electrophoretic mobility greater than a predetermined electrophoretic mobility among the charged particles based on an electrophoretic mobility and to measure a current of electrophoretic mobility particles; an aerodynamic particle collector configured to collect charged particles passing through the electrophoretic mobility particle collector based on an inertial force of the charged particles and to measure a current of aerodynamic particles; a filter configured to collect charged particles passing through the aerodynamic particle collector and to measure a current of filtered particles; and a processor, wherein the processor calculates a density of the particles based on a ratio of the current of electrophoretic mobility particles, the current of aerodynamic particles, and the current of filtered particles.
2. The particle matter analysis device as claimed in claim 1, wherein the processor is configured to calculate an overall current of the collected particles obtained by adding up the current of electrophoretic mobility particles, the current of aerodynamic particles, and the current of filtered particles, to calculate an average electrophoretic mobility particle diameter based on a ratio of the current of electrophoretic mobility particles to the calculated overall current, to calculate a dynamic overall current of the collected particles obtained by adding up the current of aerodynamic particles and the current of filtered particles, and to calculate a density of the particles based on the calculated average electrophoretic mobility particle diameter and the current of aerodynamic particles with respect to the calculated dynamic overall current.
3. The particle matter analysis device as claimed in claim 2, wherein the processor is configured to calculate a total number concentration of the particles based on a predetermined log-normal distribution, a predetermined variance value of a particle distribution, and the calculated average electrophoretic mobility particle diameter.
4. The particle matter analysis device as claimed in claim 1, further comprising a nozzle including a multi-orifice including a plurality of flow paths arranged between the electrophoretic mobility particle collector and the aerodynamic particle collector and narrowing from the electrophoretic mobility particle collector toward the aerodynamic particle collector.
5. The particle matter analysis device as claimed in claim 1, wherein the aerodynamic particle collector comprises: a first aerodynamic particle collector configured to collect charged particles passing through the electrophoretic mobility particle collector and to measure a first current of aerodynamic particles; and a second aerodynamic particle collector configured to collect charged particles passing through the first aerodynamic particle collector and to measure a second current of aerodynamic particles.
6. The particle matter analysis device as claimed in claim 5, wherein the processor is configured to calculate an average electrophoretic mobility particle diameter, a variance value of particle distribution and a particle density based on the measured current of electrophoretic mobility particles, the first current of aerodynamic particles, the second current of aerodynamic particles, and the current of filtered particles.
7. The particle matter analysis device as claimed in claim 1, wherein the electrophoretic mobility particle collector and the aerodynamic particle collector are integrally formed on one chip through a micro-electro mechanical systems (MEMS) process.
8. The particle matter analysis device as claimed in claim 1, wherein the electrophoretic mobility particle collector comprises first and second electrodes spaced apart from each other in a facing manner in a direction perpendicular to a flow direction in which the charged particles move, wherein the first and second electrodes form a uniform electric field in a direction from the first electrode to the second electrode upon receiving a predetermined voltage from the power supply device, and the second electrode collects particles having an electrophoretic mobility greater than a predetermined electrophoretic mobility.
9. A particle matter analysis method comprising: charging particles included in intaken air; collecting particles having an electrophoretic mobility greater than a predetermined electrophoretic mobility among the charged particles based on the electrophoretic mobility and measuring a current of electrophoretic mobility particles; collecting charged particles passing through an electrophoretic mobility particle collector based on an inertial force of the charged particles and measuring a current of aerodynamic particles; collecting charged particles passing through an aerodynamic particle collector and measuring a current of filtered particles; and calculating a density of the particles based on a ratio of the current of electrophoretic mobility particles, the current of aerodynamic particles, and the current of filtered particles.
10. The particle matter analysis method as claimed in claim 9, wherein the calculating of a density of particles comprises calculating an overall current of the collected particles obtained by adding up the current of electrophoretic mobility particles, the current of aerodynamic particles, and the current of filtered particles, calculating an average electrophoretic mobility particle diameter based on a ratio of the current of electrophoretic mobility particles to the calculated overall current, calculating a dynamic overall current of the collected particles obtained by adding up the current of aerodynamic particles and the current of filtered particles, and calculating a density of the particles based on the calculated average electrophoretic mobility particle diameter and the current of aerodynamic particles with respect to the calculated dynamic overall current.
11. The particle matter analysis method as claimed in claim 10, further comprising: calculating a total number concentration of the particles based on a predetermined log-normal distribution, a predetermined variance value of a particle distribution, and the calculated average electrophoretic mobility particle diameter.
12. The particle matter analysis method as claimed in claim 9, wherein the measuring of the current of aerodynamic particles comprises collecting charged particles passing through the electrophoretic mobility particle collector and measuring a first current of aerodynamic particles, and collecting charged particles passing through a first aerodynamic particle collector and measuring a second current of aerodynamic particles.
13. The particle matter analysis method as claimed in claim 12, wherein the calculating of a density of particles comprises calculating an average electrophoretic mobility particle diameter, a variance value of particle distribution and a particle density based on the measured current of electrophoretic mobility particles, the first current of aerodynamic particles, the second current of aerodynamic particles, and the current of filtered particles.
14. A manufacturing method of a particle matter analysis device, the manufacturing method comprising: plating a metal thin film on a first substrate; forming a first collecting electrode of an electrophoretic mobility particle collector by patterning the metal thin film plated on the first substrate; plating a metal thin film on a second substrate; forming a second collecting electrode of an electrophoretic mobility particle collector and a collision electrode of an aerodynamic particle collector by patterning the metal thin film plated on the second substrate; plating a photosensitive film on the metal thin film with the electrodes of the second substrate formed thereon; forming a region of the electrophoretic mobility particle collector and a region of the aerodynamic particle collector by patterning the plated photosensitive film; activating a surface by plasma-treating the patterned photosensitive film; and bonding the first substrate and the second substrate.
15. The manufacturing method as claimed in claim 14, further comprising: packaging the outside of the bonded first substrate and the second substrate with a shielding case.
Description
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0028] The above and/or other aspects of the disclosure will be more apparent by describing certain embodiments of the disclosure with reference to the accompanying drawings, in which:
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DETAILED DESCRIPTION OF THE EMBODIMENTS
[0049] Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. The embodiments described herein may be variously modified. Specific embodiments may be illustrated in the drawings and described in detail in the detailed description. It should be understood, however, that the specific embodiments disclosed in the accompanying drawings are intended only to facilitate understanding of various embodiments. Therefore, the technical idea is not limited by the specific embodiments disclosed in the accompanying drawings but includes all equivalents or alternatives falling within the spirit and scope of the disclosure.
[0050] Terms including ordinals, such as first, second, etc., may be used to describe various elements but such elements are not limited to the above terms. The above terms are used only for the purpose of distinguishing one component from another.
[0051] In this specification, the terms “comprise” or “have” and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. It is to be understood that when an element is referred to as being “connected” to another element, it can be directly on or directly connected to the other element or layer, or intervening elements or layers may be present. Meanwhile, when an element is referred to as being “directly connected” to another element, it should be understood that there are no other elements in between.
[0052] In the meantime, “module” or “part” for components used in the present specification performs at least one function or operation. Also, “module” or “part” may perform functions or operations by hardware, software, or a combination of hardware and software. Also, a plurality of “modules” or a plurality of “parts” except for a “module” or “part” to be performed in a specific hardware or performed in at least one processor may be integrated into at least one module. The singular expressions include plural expressions unless the context clearly dictates otherwise.
[0053] In the description of the disclosure, order of each step should be understood to be non-limiting, unless a preceding step must be performed logically and temporally before a subsequent step. In other words, except for the exceptional case above, even if a process described as a subsequent step is performed before a process described as a preceding step, the nature of the disclosure is not affected and the claim should be defined regardless of order of the steps. In this disclosure, “A or B” is defined to refer to include both A and B as well as selectively indicating either A or B. It is also to be understood that the term “comprise” is intended to encompass other elements in addition to the elements listed as being included.
[0054] Only essential components necessary for explanation of the disclosure are described in this specification, and components not related to the essence of the disclosure are not mentioned. It should not be construed in an exclusive sense that only the recited elements are included, but should be interpreted in a non-exclusive sense to include other elements as well.
[0055] In addition, in the description of the disclosure, when it is determined that a detailed description of known functions or components related thereto may unnecessarily obscure the gist of the disclosure, the detailed description thereof will be abbreviated or omitted. Meanwhile, each embodiment may be independently implemented or operated, but each embodiment may be implemented or operated in combination.
[0056]
[0057] Referring to
[0058] The charger 110 may receive air including particles (e.g., dust, fine dust, ultrafine dust, etc.) through an inlet. For example, the ultrafine dust may be nanoparticles having a diameter of 0.3 μm or smaller or micron particles having a diameter of 2.5 μm to 0.3 μm. Also, the charger 110 may be applied with a high voltage from a power supply (not shown). The charger 110 may charge introduced particles with the applied high voltage. That is, particles introduced through the inlet may be charged in the charger 110. The particles charged in the charger 110 may move to the electrophoretic mobility particle collector 120.
[0059] The electrophoretic mobility particle collector 120 may collect particles having an electrophoretic mobility greater than a predetermined electrophoretic mobility among the charged particles based on the electrophoretic mobility. The electrophoretic mobility particle collector 120 may include an ammeter and measure a current of particles collected at the electrophoretic mobility particle collector 120 (hereinafter called “a current of electrophoretic mobility particles”). The electrophoretic mobility particle collector 120 may include two electrodes 121 and 122 arranged to be spaced apart from each other on the left and right (or upper and lower sides) with reference to a direction of movement of the charged particles. The two electrodes 121 and 122 may be formed in a plate shape. The plate-shaped electrodes 121 and 122 spaced apart from each other may be applied with a high voltage from a power supply. A uniform electric field may be formed between the electrodes 121 and 122 to which high voltage is applied. When the charged particles pass between the electrodes 121 and 122 where the electric field is formed, some particles having an electrophoretic mobility greater than a constant electrophoretic mobility due to the electric field may be collected by the electrophoretic mobility particle collector 120. Since the collected partial particles are charged, the electrophoretic mobility particle collector 120 may measure a current from the collected particles. The current measured by the electrophoretic mobility particle collector 120 may be a current of electrophoretic mobility particles I.sub.e. Particles that are not collected by the electrophoretic mobility particle collector 120 may move to the aerodynamic particle collector 130.
[0060] The aerodynamic particle collector 130 includes a collision electrode 131, and the collision electrode 131 may collect some particles having a large inertial force based on the inertial force of the charged particles. The aerodynamic particle collector 130 may include an ammeter and measure a current from the collected particles. The current measured by the aerodynamic particle collector 130 may be a current of aerodynamic particles I.sub.a. Particles that are not collected in the aerodynamic particle collector 130 may move to the filter 140.
[0061] The filter 140 may include a filter electrode 141. The filter electrode 141 may collect the other remaining particles that are not collected by the electrophoretic mobility particle collector 120 and the aerodynamic particle collector 130. The filter 140 may also include an ammeter and measure a current from the collected particles. The current measured by the filter 140 may be a current of filtered particles I.sub.f.
[0062] The particles introduced together with air into the particle matter analysis device 100 may be collected by all of the electrophoretic mobility particle collector 120, the aerodynamic particle collector 130, and the filter 140. Accordingly, the sum of the current of electrophoretic mobility particles I.sub.e, the current of aerodynamic particles I.sub.a, and the current of filtered particles I.sub.f is equal to a total current I.sub.tot of the charged particles in the charger 110. The introduced air may be discharged through an outlet.
[0063] The processor 150 may receive the current of electrophoretic mobility particles, the current of aerodynamic particles, and the current of filtered particles from the electrophoretic mobility particle collector 120, the aerodynamic particle collector 130, and the filter 140, respectively. The processor 150 may calculate an average electrophoretic mobility particle diameter, an average density of an average aerodynamic particle diameter, an average charge amount, a number concentration of particles, a particle mass concentration, and the like based on a ratio of the received current of electrophoretic mobility particles, current of aerodynamic particles, and current of filtered particles.
[0064] Meanwhile, the particle matter analysis device 100 may further include a particle separator (not shown). The particle separator may be disposed on a front portion of the charger 110 to separate particles to be analyzed from particles introduced with air. That is, particles in the air may be separated into particles to be analyzed (or analysis target particles) and particles not to be analyzed, while passing through the particle separator, and the separated particles to be analyzed may be introduced into the particle matter analysis device 100. For example, the particle separator may be a virtual impactor that separates specific particles using an inertial force.
[0065] For example, the analysis target particles may be nanoparticles having a diameter of 0.3 μm or smaller. When the analysis target particles are nanoparticles, the particle separator may selectively separate the nanoparticles from the particles in the air for analysis. As an embodiment, the particle separator may include an inlet through which air flows, a low-speed flow path extending in the same direction as that of the inlet, and a high-speed flow path extending in a direction perpendicular to the inlet and low-speed flow path. The particle separator may selectively separate nanoparticles in the air using an inertial force. Specifically, among the particles in the air introduced into the inlet port, micron particles having a relatively high inertia may move in the low-speed flow path by maintaining a linear motion, and nanoparticles having a relatively small size may move in the high-speed flow path due to a small inertia. Accordingly, only the nanoparticles may be selectively separated from the air. The separated nanoparticles may be introduced into the particle matter analysis device 100 connected to the high-speed flow path.
[0066] Alternatively, the analysis target particles may be micron particles having a diameter between 2.5 μm and 0.3 μm, particles having a diameter of 2.5 μm or smaller, or particles having a particle diameter within a specific range. For example, the particle separator may separate particles having a diameter of 2.5 μm or smaller and supply them to the particle matter analysis device 100, and the particle matter analysis device 100 may calculate a density or the like of the separated particles. That is, the particle matter analysis device 100 may be applied to any particles, and the size of the analysis target particles may be appropriately selected according to purposes of analysis.
[0067] A specific configuration of the particle matter analysis device 100 and a process of analyzing particles will be described later.
[0068]
[0069] The charger 110 may electrically charge particles introduced with air to generate charged particles. For example, the charger 110 may charge particles using corona discharge. Corona discharge, a form of gas discharge, is a phenomenon in which discharge occurs when a high voltage is applied to a tip-shaped electrode. The charger 110 may include a tip-shaped electrode 111 and a ring-shaped electrode 112. The tip-shaped electrode 111 may be a discharge electrode including a conductive metal and the ring-shaped electrode 112 may be a ground electrode including a conductive metal. For example, the conductive metal may include copper, tungsten, aluminum, stainless steel, and the like.
[0070] Particles together with air may be introduced through the inlet into the charger 110 of the particle matter analysis device 100. The outlet of the charger 110 and the inlet of the electrophoretic mobility particle collector 120 may be connected to each other. Accordingly, the introduced particles may pass through the inside of the ring-shaped electrode 112 and move to the electrophoretic mobility particle collector 120.
[0071] An enlarged view of the tip-shaped electrode 111 and the ring-shaped electrode 112 is shown in a. The ring-shaped electrode 112 may be disposed on an inner surface of the charger 110. The ring-shaped electrode 112 may be formed in a circular, elliptical, or polygonal shape according to an inner shape of the charger 110. The tip-shaped electrode 111 may be spaced apart from the ring-shaped electrode 112 and disposed at a central region. The tip-shaped electrode 111 may generate corona discharge from a tip end to the ring-shaped electrode 112 when a high voltage is applied from the power supply. Electrons around the tip end are accelerated to collide with air molecules, and the air molecules may be separated into cations and electrons due to the collision. The separated cations may adhere to particles passing between the tip-shaped electrode 111 and the ring-shaped electrode 112 to generate charged particles.
[0072] Referring to
n(d.sub.e)=α.Math.d.sub.e.sup.β (Equation 1)
[0073] Here, n(d.sub.e) is the number of charges per unit particle and α, β are constants.
[0074] That is, the number of charges per particle of the charger 110 may be fitted as a power-law function according to the size of the particles. The particles charged in the charger 110 may move to the electrophoretic mobility particle collector 120.
[0075] A current value due to charged particles having a specific particle diameter may be expressed as Equation 2, and a total current value of charged particles may be expressed as Equation 3.
I(d.sub.e)=e.Math.n(d.sub.e).Math.Q.Math.N(d.sub.e) (Equation 2)
[0076] Here, I (d.sub.e) is current, e is unit charge amount and Q is flow rate.
I.sub.tot=I.sub.e+I.sub.a+I.sub.f=∫I(d.sub.e)dd.sub.e=e.Math.Q∫n(d.sub.e).Math.N(d.sub.e)dd.sub.e (Equation 3)
[0077]
[0078] An inlet of the electrophoretic mobility particle collector 120 may be connected to an outlet of the charger 110. Thus, the particles charged in the charger 110 may be moved to the electrophoretic mobility particle collector 120. The charged particles may be introduced into the inlet of the electrophoretic mobility particle collector 120 and may be discharged through an outlet located in the opposite direction (e.g., moved in an X-axis direction). As shown in
[0079] The first and second electrodes 121 and 122 may be formed in a plate shape. The first and second electrodes 121 and 122 may receive a predetermined voltage from a power supply. For example, the first electrode 121 may be applied with a predetermined voltage, and the second electrode 122 may be grounded. When the first and second electrodes 121 and 122 are applied with a voltage, a uniform electric field may be formed in a direction of the second electrode 122 from the first electrode 121 in the internal space of the electrophoretic mobility particle collector 120 (e.g., Y-axis direction). The particles which are charged as positive charges by the formed electric field may be forced in a direction of the electric field. The charged particles may have a first velocity vector component (e.g., X-axis direction) based on air flow and a second velocity vector component (e.g., Y-axis direction) based on the electric field and move in a direction of the sum of the first velocity vector component and the second velocity vector component. The charged particles having a large size of the second velocity vector component may move in the direction of the second electrode 122 and may be collected in the second electrode 122. Thus, the second electrode 122 may collect particles having an electrophoretic mobility greater than a predetermined electrophoretic mobility. Meanwhile, particles having a small size of the second velocity vector component may not be collected and may move in the exit direction.
[0080] The size of the second velocity vector component may be represented by the electrophoretic mobility of the charged particles as shown in Equation 4. That is, the electrophoretic mobility may refer to a velocity of the charged particles in a unit electric field, and as particles have larger electrophoretic mobility, a velocity thereof in the electric field direction may increase.
[0081] Here, Z.sub.e is electrophoretic mobility of the particles, e is unit charge amount, C is Cunningham slip correction factor, μ is gas viscosity, n is the number of charges attached to particles, and d.sub.e is electrophoretic mobility particle diameter.
[0082] Therefore, as shown in Equation 4, particles having a small electrophoretic mobility particle diameter has large electrophoretic mobility (second velocity vector component), and particles having a large electrophoretic mobility particle diameter may have small electrophoretic mobility (second velocity vector component). Therefore, charged particles having an electrophoretic mobility particle diameter smaller than or equal to a predetermined value may be collected by the second electrode 122, and charged particles having an electrophoretic mobility particle diameter exceeding the predetermined value may not be collected by the second electrode 122 and may be moved to the aerodynamic particle collector 130 through the outlet. That is, the predetermined value may be an upper limit value of the electrophoretic mobility particle diameter of the charged particles collected in the second electrode 122.
[0083] Meanwhile, a ratio (collection efficiency) η.sub.e of charged particles collected by the electrophoretic mobility particle collector 120 may be adjusted according to a magnitude of a voltage difference between the first electrode 121 and the second electrode 122 (or voltage applied to the first electrode). The collection efficiency of the electrophoretic mobility particle collector 120 may be expressed as shown in Equation 5.
[0084] Here, η.sub.e is collection efficiency, Ze is electrophoretic mobility of particles, L.sub.e is channel length of electrophoretic mobility particle collector, we is channel width, V.sub.e is voltage applied to the electrophoretic mobility particle collector, and Q.sub.air is sampling flow rate, and h is channel height.
[0085] Referring to
[0086] The amount of charged particles collected by the second electrode 122 may be measured as a current value. That is, the current value I.sub.e measured at the second electrode 122 may vary depending on the amount of collected charged particles. The outlet of the electrophoretic mobility particle collector 120 and the inlet of the aerodynamic particle collector 130 may be connected to each other. Accordingly, charged particles that are not collected by the electrophoretic mobility particle collector 120 may move to the aerodynamic particle collector 130.
[0087]
[0088] The inlet of the aerodynamic particle collector 130 may be connected to the outlet of the electrophoretic mobility particle collector 120. Accordingly, charged particles that are not collected by the electrophoretic mobility particle collector 120 may move to the aerodynamic particle collector 130. In the disclosure, a part from the outlet of the electrophoretic mobility particle collector 120 to the inlet of the aerodynamic particle collector 130 will be referred to as a nozzle. The nozzle may be formed such that a cross-sectional area of the inlet of the aerodynamic particle collector 130 is smaller than a cross-sectional area of the outlet of the electrophoretic mobility particle collector 120. That is, as illustrated in
[0089] An aerodynamic particle diameter of the particles in which the number of particles collected by the collision electrode 131 and the number of bypassing particles are equal is a cut-off diameter and may be expressed as Equation 6.
[0090] Here, d.sub.a,50 is aerodynamic particle diameter, μ is gas viscosity, W.sub.a is nozzle width of aerodynamic particle collector, Stk.sub.50 is Stokes number of cut-off diameter, ρ.sub.p is particle density, Cc is Cunningham slip correction factor, and Q.sub.air is sampling flow rate.
[0091] A shape of the aerodynamic particle collector may be designed with reference to Equation 6. In addition, Equation 6 may be used to calculate an average aerodynamic particle diameter based on a current ratio of the current I.sub.a measured by the aerodynamic particle collector 130 and the current (I.sub.a+I.sub.f) of the particles introduced into the aerodynamic particle collector.
[0092]
[0093] The amount of charged particles collected by the collision electrode 131 may be measured as a current value. That is, the current value I.sub.a measured by the collision electrode 131 may vary depending on the amount of collected charged particles. The filter 140 may be located below the aerodynamic particle collector 130.
[0094] The filter 140 may collect all the remaining charged particles that are not collected by the aerodynamic particle collector 130. The filter 140 may include a filter electrode 141. For example, the filter electrode 141 may be formed in a plate shape and may include a conductive metal such as copper, tungsten, aluminum, and stainless steel. The filter electrode 141 may be disposed in a direction perpendicular to a flow direction of the charged particles. The amount of charged particles collected by the filter 141 may be measured as a current value. That is, the current value I.sub.f measured at the filter electrode 141 may vary depending on the amount of collected charged particles.
[0095] As described above, the particles charged in the charger 110 are collected by the electrophoretic mobility particle collector 120, the aerodynamic particle collector 130, and the filter 140, and each unit may measure the current of electrophoretic mobility particles I.sub.e, the current of aerodynamic particles I.sub.a, and the current of filtered particles I.sub.f. Because the charged particles are all collected in each unit, a total current I.sub.tot of the charged particles is equal to the sum of the current of electrophoretic mobility particles I.sub.e, the current of aerodynamic particles I.sub.a, and the current of filtered particles I.sub.f. The current of electrophoretic mobility particles I.sub.e, the current of aerodynamic particles I.sub.a, and the current of filtered particles I.sub.f measured at each unit are delivered to the processor, and the processor may calculate a density or the like of the particles based on the delivered current.
[0096]
[0097] The particle matter analysis device 100 illustrated in
[0098] The nozzle 160 may be disposed between the electrophoretic mobility particle collector 120 and the aerodynamic particle collector 130 and include a multi-orifice including a plurality of flow paths narrowing in the direction to the aerodynamic particle collector 130 from the electrophoretic mobility particle collector 120.
[0099] When a vacuum pump reduces pressure of the orifice, a flow velocity (flow velocity of air containing particles) is generated in the orifice due to a pressure difference, and the flow velocity may increase as the pressure difference increases. However, because the flow velocity cannot be greater than a sound velocity, a chocked flow phenomenon in which the flow velocity is equal to the sound velocity may occur even if the pressure at an outlet of the orifice is lowered. Since the flow velocity becomes equal to the sound velocity, a constant flow rate may be supplied to the aerodynamic particle collector 130. Therefore, the particle matter analysis device of the disclosure may supply a constant flow rate without a flow sensor through a critical orifice provided therein. In case of the chocked flow, the flow rate may be calculated using an orifice nozzle width, the number of nozzles, and Equation 7.
[0100] Here, Q.sub.air is flow rate, c.sub.o is discharge coefficient=0.8 (in case of a rectangular orifice), n.sub.o is critical orifice number, wo is critical orifice width, h is channel height, P.sub.air is air pressure (atmospheric pressure 1 atm), ρ.sub.air is air density (atmospheric pressure 1.23 kg/m.sup.3), and λ.sub.air is specific heat ratio of air=1.4.
[0101] The nozzle may be a single orifice or may be a nozzle realized as a multi-orifice including a plurality of orifices. As the number of orifices increases, an area in which air circulates at a rear end of an electrophoretic mobility particle diameter analyzer may be minimized, thus increasing stability of classification efficiency. As an embodiment, a flow rate range may be 0.3 to 3 LPM, and the number of nozzles may be calculated by Equation 7.
[0102] As described above, each component of the particle matter analysis device of the disclosure may measure the current from the collected charged particles. The measured current may be delivered to the processor. The processor may analyze the particles based on the delivered current. That is, the particle matter analysis device may analyze the particles by measuring only the current. First, a process in which the processor receives the measured current and calculates a density will be described.
[0103] Assuming that a size distribution of particles introduced into the particle matter analysis device follows a log-normal distribution, a particle size distribution may be expressed as Equation 8.
[0104] Here, N(d.sub.e) is particle size distribution, N.sub.tot is total number concentration, σ is variance value, and d.sub.e,m is an average electrophoretic mobility particle diameter.
[0105] A ratio (first current ratio) of the current based on the charged particles collected by the electrophoretic mobility particle collector 120 to a total current may be expressed as Equation 9.
[0106] Here, η.sub.e is collection efficiency of electrophoretic mobility particle collector, n(d.sub.e) is the number of charges per unit particle, d.sub.e is electrophoretic mobility particle diameter, d.sub.e,m is average electrophoretic mobility particle diameter, and σ is variance value.
[0107] As described above, the collection efficiency η.sub.e may be controlled by controlling a voltage applied to the first electrode. The charge number per unit particle n(d.sub.e) may be obtained from Equation 1, and the electrophoretic mobility particle diameter d.sub.e in Equation 6 may be treated as a constant. If the variance value σ is assumed to be a specific value (e.g., 1.6 or 1.8), an unknown in Equation 9 is only the average electrophoretic mobility particle diameter of the particles. Therefore, the average electrophoretic mobility particle diameter d.sub.e,m of the particles may be calculated from Equation 9.
[0108] A ratio (second current ratio) of the current due to the charged particles collected by the aerodynamic particle collector to the current due to the charged particles introduced into the aerodynamic particle collector may be expressed as Equation 10.
[0109] Here, η.sub.a is collection efficiency of the aerodynamic particle collector, and ρ.sub.eff is density.
[0110] Equation 10 may be expressed by modifying and substituting a density equation, Equation 11.
[0111] Here, ρ.sub.0 is unit density (1 g/cm.sup.3), Cc is Cunningham slip correction factor, d.sub.a is aerodynamic particle diameter, and d.sub.e is electrophoretic mobility particle diameter.
[0112] Therefore, because the average electrophoretic mobility particle diameter d.sub.e,m of the particles is calculated from Equation 9, density of the particles may be calculated from Equation 10. That is, the particle matter analysis device may calculate an average electrophoretic mobility particle diameter and density of particles using only the measured current. In addition, a total number concentration may be calculated using the calculated average electrophoretic mobility particle diameter of the particles and Equation 8.
[0113] Meanwhile, the particle matter analysis device may further include a memory (not shown). The particle matter analysis device may generate a relationship between the measured currents I.sub.e, I.sub.a, and I.sub.f and the density of the particles ρ.sub.eff as a database and store the generated database in the memory. That is, the processor may retrieve the density from the database, without calculating the density each time it is measured. Therefore, the particle matter analysis device may reduce a density calculation time and a calculation load. For example, the particle matter analysis device may store the relation data between the first current ratio R.sub.1 and the average electrophoretic mobility particle diameter d.sub.e,m and the relation data between the average electrophoretic mobility particle diameter d.sub.e,m and an effective density based on the second current ratio R.sub.2 in the memory. Therefore, the particle matter analysis device may immediately calculate the density when only a measured current is input. In addition, the particle matter analysis device may further include an outputter (not shown) for providing analysis information of particles to a user. For example, the outputter may be realized as a speaker or display.
[0114] Meanwhile, the particle matter analysis device may include a plurality of aerodynamic particle collectors.
[0115]
[0116] As described above, particles introduced into the particle matter analysis device may be charged by a high voltage applied to the charger. In addition, an electric field is formed by a high voltage applied to the electrophoretic mobility particle collector, and charged particles having an electrophoretic mobility of a predetermined size or greater may be collected by the electrophoretic mobility particle collector by the generated electric field. Charged particles that are not collected by the electrophoretic mobility particle collector may be collected by the aerodynamic particle collector or the filter. The electrophoretic mobility particle collector may measure the current of electrophoretic mobility particles I.sub.e, the aerodynamic particle collector may measure the current of aerodynamic particles I.sub.a, and the filter may measure the current of filtered particles I.sub.f. That is, the particle matter analysis device may include three ammeters.
[0117] However, when a high voltage is applied to the electrophoretic mobility particle collector at a predetermined period as in the embodiment illustrated in
[0118] Specifically, the power supply may apply a high voltage to the electrophoretic mobility particle collector at regular periods. As an example, as illustrated in
[0119] The particles introduced into the particle matter analysis device may be charged in the charger. When 0V is applied to the electrophoretic mobility particle collector, an electric field is not formed in the electrophoretic mobility particle collector. Therefore, charged particles are not collected in the electrophoretic mobility particle collector. Charged particles may be collected in both aerodynamic particle collectors and filters. Thus, the current measured in the aerodynamic particle collector and filter may be the total current I.sub.tot.
[0120] After a certain time (e.g., 15 seconds), a high voltage (e.g., 120V) may be applied to the electrophoretic mobility particle collector. When the high voltage is applied to the electrophoretic mobility particle collector, an electric field may be formed in the electrophoretic mobility particle collector. Therefore, although electrophoretic mobility particle collector collects charged particles, it is not possible to directly measure the current of electrophoretic mobility particles I.sub.e because the electrophoretic mobility particle collector does not include an ammeter. Some of the charged particles that are not collected by the electrophoretic mobility particle collector are collected by the aerodynamic particle collector, and the aerodynamic particle collector may measure the current of aerodynamic particles I.sub.a. The remaining charged particles that are not collected are collected by the filter, and the filter may measure the current of filtered particles I.sub.f.
[0121] That is, the particle matter analysis device may obtain the total current I.sub.tot when a high voltage is not applied to the electrophoretic mobility particle collector (e.g., at 0V). In addition, when a high voltage is applied to the electrophoretic mobility particle collector (e.g., at 120V), the particle matter analysis device may directly obtain the current of aerodynamic particles I.sub.a and the current of filtered particles I.sub.f. The particle matter analysis device may indirectly obtain the current of electrophoretic mobility particles I.sub.e by subtracting the collected particle current I.sub.a and the current of filtered particles I.sub.f from the total current I.sub.tot. Therefore, by periodically applying the high voltage to the electrophoretic mobility particle collector, the particle matter analysis device may directly and indirectly obtain the total current I.sub.tot, the current of electrophoretic mobility particles I.sub.e, the current of aerodynamic particles I.sub.a, and the current of filtered particles I.sub.f. A process of analyzing density of particles based on the obtained currents and the current ratios are the same as those described above, so a detailed description thereof will be omitted.
[0122]
[0123] Referring to
I.sub.tot=I.sub.e+I.sub.α1+I.sub.α2+I.sub.f=∫I(d.sub.e)dd.sub.e=e.Math.Q∫n(d.sub.e).Math.N(d.sub.e)dd.sub.e (Equation 12)
[0124] A current ratio that may be obtained in the particle matter analysis device 100a of
[0125] In Equation 13 to Equation 15, unknowns are an average electrophoretic mobility particle diameter d.sub.e,m, an effective density ρ.sub.eff, and a variance value σ. Since there are three equations and three unknowns, the average electrophoretic mobility particle diameter d.sub.e,m, the effective density ρ.sub.eff, and the variance value σ may be calculated using Equation 13 to Equation 15. That is, the particle matter analysis device 100a according to the embodiment of
[0126]
[0127] Referring to
[0128] The particle matter analysis device may collect particles having an electrophoretic mobility greater than a predetermined electrophoretic mobility among charged particles based on the electrophoretic mobility and measure the current of electrophoretic mobility particles in operation S1220. Particles having an electrophoretic mobility smaller than the predetermined electrophoretic mobility may not be collected. The particle matter analysis device may collect charged particles passing through the electrophoretic mobility particle collector based on an inertial force of the charged particles and measure the current of aerodynamic particles in operation S1230. Also, the particle matter analysis device may collect charged particles passing through the aerodynamic particle collector and measure the current of filtered particles in operation S1240.
[0129] The particle matter analysis device may calculate density of the particles based on a ratio of the current of electrophoretic mobility particles, the current of aerodynamic particles, and the current of filtered particles in operation S1250. For example, the particle matter analysis device may calculate a total current of the collected particles obtained by adding up the current of electrophoretic mobility particles, the current of aerodynamic particles, and the current of filtered particles, and calculate an average electrophoretic mobility particle diameter based on the ratio of the current of electrophoretic mobility particles to the calculated total currents.
[0130] After calculating the average electrophoretic mobility particle diameter, the particle matter analysis device may calculate a total dynamic current of the collected particles obtained by adding up the current of aerodynamic particles and the current of filtered particles, and calculate density of the particles based on the calculated average electrophoretic mobility particle diameter and the current of aerodynamic particles over the total dynamic current. In addition, the particle matter analysis device may calculate a total number concentration of particles based on a predetermined log-normal distribution, a predetermined variance value of a particle distribution, and the calculated average electrophoretic mobility particle diameter.
[0131] Meanwhile, the particle matter analysis device may include a plurality of aerodynamic particle collectors. In this case, the particle matter analysis device may collect charged particles passing through the electrophoretic mobility particle collector and measure the first current of aerodynamic particles, and may collect charged particles passing through the first aerodynamic particle collector and measure the second current of aerodynamic particles. Also, the particle matter analysis device may calculate an average electrophoretic mobility collected particle diameter, a variance value of a particle distribution, and density of the particles based on the measured electrophoretic mobility particle diameter, the first current of aerodynamic particles, the second current of aerodynamic particles, and the current of filtered particles.
[0132] So far, various embodiments of analyzing the components of the particle matter analysis device and particles have been described. Hereinafter, a manufacturing method of a particle matter analysis device will be described.
[0133]
[0134] An electrophoretic mobility particle collector and an aerodynamic particle collector of a particle matter analysis device may be integrally manufactured as a single chip through a micro-electro mechanical systems (MEMS) process.
[0135] Referring to
[0136]
[0137]
[0138]
[0139]
[0140]
[0141]
[0142] Referring to
[0143]
[0144] Referring to
[0145] Next, a metal thin film may be plated on a second substrate (S1530), and the metal thin film plated on the second substrate may be patterned to form a second electrode of the electrophoretic mobility particle collector and a collision electrode of an aerodynamic particle collector (S1540).
[0146] After the electrodes are formed on the first and second substrates, a photosensitive film may be plated on the metal thin film on which the electrode of the second substrate is formed (S1550). The plated photosensitive film may be patterned to form a region (channel) of the electrophoretic mobility particle collector and a region (channel) of the aerodynamic particle collector (S1560).
[0147] The patterned photosensitive film may be plasma-treated to activate a surface thereof (S1570), and the first substrate and the second substrate may be bonded in a state where heat and pressure are applied (S1580). An outer side of the bonded first and second substrates may be packaged by a shielding case. In addition, a charger and a filter may be connected to a particle matter analysis module in which the electrophoretic mobility particle collector and the aerodynamic particle collector are manufactured based on an MEMS, and a connector for measuring a current or applying a high voltage, a processor for calculating density or the like may be connected thereto, thereby completing a particle matter analysis device.
[0148] As described above, the particle matter analysis device according to an embodiment of the disclosure may accurately measure a density of particles contained in the air in real time. In addition, since the particle matter analysis device can be embedded in a single integrated chip, the particle matter analysis device enables miniaturization and low cost production, easy transportation, and easy application to various industrial fields. In addition, because a high-precision density value may be obtained, accuracy of measurement of a mass concentration may be remarkably improved compared to the related art method of calculating a mass concentration by uniformly applying a certain density value.
[0149] The particle matter analysis method according to various embodiments described above may be provided as a computer program product. The computer program product may include the S/W program itself or a non-transitory computer readable medium storing the S/W program.
[0150] The non-transitory computer readable medium is a medium that semi-permanently stores data therein, rather than a medium storing data for a short time such as a register, a cache, a memory, or the like, and is readable by a device. In detail, various applications or programs described above may be stored and provided in the non-transitory computer readable medium such as a compact disk (CD), a digital versatile disk (DVD), a hard disk, a Blu-ray disk, a universal serial bus (USB), a memory card, and a read only memory (ROM).
[0151] While the disclosure has been described with reference to the embodiments, the disclosure is not limited to the above-described specific embodiments, and it will be understood by those skilled in the related art that various modifications and variations may be made without departing from the scope of the disclosure as defined by the appended claims, as well as these modifications and variations should not be understood separately from the technical spirit and prospect of the disclosure.