KR102344462B1 - Apparatus for sensing particle - Google Patents

Abstract

The particle sensing device according to the embodiment includes a light emitting unit emitting light and a first light emitting unit disposed to cross the optical axis of the light emitting unit under the light emitting unit and providing a first flow path through which first air including particles flows An optical axis under the flow path unit, an air supply unit for providing second air with particles filtered in the same direction as the direction in which the first air flows between the first flow path and the light emitting unit and between the first flow path and the light receiving unit, and the first flow path unit It may include a light receiving unit which is disposed in the first flow path and is incident on the light passing through the first flow path unit.

Description

Particle sensing device {Apparatus for sensing particle}

The embodiment relates to a particle sensing device.

In general, in the case of a conventional dust sensing device that senses particles such as dust, information about the dust is obtained by irradiating light toward the dust and sensing the light scattered from the dust.

When dust to be sensed continuously flows into the dust sensing device, the inside of the dust sensing device is contaminated by the dust, so that the dust cannot be accurately sensed. In particular, when dust introduced into the dust sensing device is accumulated in an optical system inside the dust sensing device, the performance of the dust sensing device may be deteriorated.

In order to solve this problem, the user of the dust sensing device must manually clean the inside of the dust sensing device, particularly the optical system, periodically, for example, every 3 to 6 months. Due to this, the user has no choice but to be frequently exposed to an unsanitary work environment where filth such as dust gets on his/her hands, and the dust may re-scatter around the user during cleaning, which may cause inconvenience to the user.

An embodiment is to provide a particle sensing device capable of accurately sensing particles without being contaminated by dust or the like.

A particle sensing device according to an embodiment includes: a light emitting unit emitting light; a first flow path that is disposed under the light emitting part to intersect the optical axis of the light emitting part and provides a first flow path through which first air including particles flows; an air supply unit providing the second air, in which the particles are filtered, in the same direction as the flow direction of the first air between the first flow path and the light emitting unit and between the first flow path and the light receiving unit; and a light receiving unit disposed on the optical axis under the first flow path and receiving light passing through the first flow path.

For example, the first flow path may include: a first flow path inlet through which the first air is introduced; a first passage outlet through which the first air is discharged; a scattering unit positioned on the optical axis between the first flow path inlet and the first flow path exit and between the light emitting unit and the light receiving unit to scatter the particles; a first-first flow passage intermediate portion positioned between the first flow passage inlet and the scattering portion; and a 1-2 flow path intermediate part positioned between the scattering part and the first flow path outlet part, wherein the first flow path inlet part, the 1-1 flow path middle part, the scattering part, and the 1-2 flow path part are included. The middle portion and the first passage outlet may form the first passage.

For example, the air supply unit includes a second flow path that is isolated from the first flow path before the scattering unit, comes into contact with the first flow path from the scattering unit, and provides a second flow path through which the second air flows. can do.

For example, the second flow path part may include a second flow path inlet part through which the second air is introduced and disposed around the first flow path inlet part; a second flow path outlet part through which the second air flows out and disposed around the first flow path outlet part; an air curtain part disposed around the scattering part to separate the upper scattering part from the light receiving part and to separate the scattering part from the light emitting part; a 2-1 passage intermediate portion disposed around the 1-1 passage intermediate portion; and a 2-2 flow path intermediate portion disposed on the periphery of the 1-2 flow passage intermediate portion, wherein the second flow passage inlet portion, the 2-1 flow passage intermediate portion, the air curtain unit, and the 2-2 flow passage The intermediate portion and the second passage outlet form the second passage, the first and second passage inlet portions are isolated from each other, the 1-1 and 2-1 passage intermediate portions are isolated from each other, and the air curtain unit and the scattering portion may be in contact with each other, intermediate portions of the first-second and second second passages may be in contact with each other, and the first and second passage outlets may be in contact with each other.

For example, the 1-1 flow passage intermediate portion is disposed in the 2-1 flow passage intermediate portion, an inner wall of the 1-1 flow passage intermediate portion forms a part of the first flow passage, and the 1-1 flow passage A portion of the second flow path may be formed between the outer wall of the intermediate portion and the inner wall of the second-first flow passage intermediate portion.

For example, the cross section of the first flow passage in the middle of the 1-1 flow passage and the cross section of the second passage in the middle of the 2-1 flow passage may have a concentric shape.

For example, the air curtain unit may include a first air curtain unit positioned between the light emitting unit and the scattering unit; and a second air curtain unit positioned between the scattering unit and the light receiving unit and spaced apart from the first air curtain unit.

For example, the 2-1 passage middle portion may include an upper 2-1 passage intermediate portion in contact with the first air curtain unit; and a lower 2-1 flow path middle part in contact with the second air curtain part and spaced apart from the upper 2-1 flow path middle part.

For example, the light emitting unit may include a light source unit; and a first opening emitting the light emitted from the light source unit toward the scattering unit and disposed on the optical axis.

For example, a cross-sectional area of the first passage may be smaller than an area of the first opening.

For example, the sum of the flow passage cross-sectional area of the first flow passage and the flow passage cross-sectional area of the second flow passage may be smaller than the area of the first opening.

For example, when the particle sensing device is driven, the first flow rate of the first air may be less than or equal to the second flow rate of the second air.

For example, the flow passage cross-sectional area of the second flow passage part may be constant at any point on the second flow passage.

For example, the particle sensing device may further include a fan disposed adjacent to the outlet of the first and second flow paths and for inducing a flow of at least one of the first and second air.

For example, the air providing unit may further include an air filtering unit configured to generate the second air by filtering the particles from the first air.

An air purifier according to another embodiment includes the particle sensing device; and an air filtering unit configured to generate the second air by filtering the particles from the first air.

The particle sensing device according to the embodiment uses the second air to prevent the light emitting part or the light receiving part from being contaminated by the particles, thereby reducing the need for cleaning, and thereby accurately sensing the particles.

1 is a schematic block diagram for explaining the concept of a particle sensing device according to an embodiment.
2 shows an exemplary profile of scattered light scattered by a particle.
FIG. 3 is a cross-sectional view illustrating an embodiment of the particle sensing device illustrated in FIG. 1 .
4A is a side cross-sectional view showing an embodiment of the intermediate portions of the 1-1 and 2-1 passages in the first and second flow passages shown in FIG. 3 , and FIG. 4B is 'A1' shown in FIG. ' This is an enlarged cross-sectional view of the part.
5 is a cross-sectional view of another embodiment of the particle sensing device shown in FIG.
FIG. 6A is a side cross-sectional view showing an embodiment of a middle part of the 1-1 and 2-1 flow paths in the first flow path part and the second flow path part shown in FIG. 5, and FIG. 6B is 'A2' shown in FIG. ' This is an enlarged cross-sectional view of the part.
7 is a cross-sectional view of another embodiment of the particle sensing device shown in FIG. 1 .
FIG. 8 is an enlarged cross-sectional view of part 'A3' in order to explain the first and second flow passages shown in FIG. 7 .
9 is an enlarged cross-sectional view of part 'B' shown in FIG. 3 .
10A is a plan view of an embodiment of the photodetector shown in FIG. 9 , and FIG. 10B is a cross-sectional view of the photodetector shown in FIG. 10A cut along the line JJ′ according to an embodiment.
11 illustrates a planar shape of another embodiment of the light sensing unit illustrated in FIG. 9 .
12 is a block diagram of an embodiment of the information analysis unit shown in FIG. 1 .
13 is a schematic cross-sectional view of an air purifier according to an embodiment.
14 is a photograph of a state in which the first air flows through the first flow path in the particle sensing device according to the comparative example.
15 is a photograph of a state in which the first and second air flows through the first and second flow passages, respectively, in the particle sensing device according to the embodiment.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings to help the understanding of the present invention by giving examples, and to explain the present invention in detail. However, embodiments according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided in order to more completely explain the present invention to those of ordinary skill in the art.

In the description of this embodiment, in the case of being described as being formed on "on or under" of each element, above (above) or below (below) ( on or under includes both elements in which two elements are in direct contact with each other or in which one or more other elements are disposed between the two elements indirectly.

In addition, when expressed as "up (up)" or "down (on or under)", the meaning of not only an upward direction but also a downward direction may be included based on one element.

Also, as used hereinafter, relational terms such as “first” and “second,” “top/top/top” and “bottom/bottom/bottom” refer to any physical or logical relationship between such entities or elements or It may be used to distinguish one entity or element from another without requiring or implying an order.

Hereinafter, the particle sensing apparatus 100 according to an embodiment will be described with reference to the accompanying drawings as follows. For convenience of description, although the particle sensing apparatus 100: 100A to 100C is described using a Cartesian coordinate system (x-axis, y-axis, and z-axis), it goes without saying that this can also be described by other coordinate systems. According to the Cartesian coordinate system, the x-axis, the y-axis, and the z-axis are orthogonal to each other, but the embodiment is not limited thereto. That is, according to another embodiment, the x-axis, the y-axis, and the z-axis may cross each other.

1 is a schematic block diagram for explaining the concept of a particle sensing device 100 according to an embodiment, and is a light absorbing unit 102 , a light emitting unit 110 , a first flow path unit 120 , and a light receiving unit. 130 , an air providing unit 140 , a signal converting unit 150 , an information analyzing unit 160 , a housing 170 , and a fan 180 .

Referring to FIG. 1 , the light emitting unit 110 serves to emit light, and may include a light source unit 112 , a lens unit 114 , and a light emitting case 116 .

The light source unit 112 serves to emit the first light L1 and may include at least one light source. The light source included in the light source unit 112 may be at least one of a light emitting diode (LED) or a laser diode (LD). is not limited to the number of For example, as a light source for implementing the light source unit 112, it may be a blue LED, a high-brightness LED, a chip LED, a high-luxe LED, or a power LED having straightness, but the light source according to the embodiment is not limited to a specific type of LED. .

If the light source unit 112 is implemented as an LED, light of a visible light wavelength band (eg, 405 nm to 660 nm) or an infrared (IR: Infrared) wavelength band (eg, 850 nm to 940 nm) can emit In addition, when the light source unit 112 is implemented as an LD, light of a red/blue wavelength band (eg, 450 nm to 660 nm) may be emitted. However, the embodiment is not limited to a specific wavelength band of the first light L1 emitted from the light source unit 112 .

Also, the intensity of the third light L3 emitted from the light emitting unit 110 may be 3000 mcd or more, but the embodiment is not limited to a specific intensity of the third light L3 emitted.

A packaging type of the light source included in the above-described light source unit 112 may be implemented as a surface mount device (SMD) type or a lead type. Here, the SMD type refers to a packaging type in which the light source of the light emitting unit 112A is mounted on a printed circuit board (PCB) through soldering, as shown in FIG. 3 to be described later. In addition, the lead type means a packaging type in which a lead that can be connected to a PCB electrode from a light source protrudes. However, the embodiment is not limited to a specific packaging type of the light source.

In addition, when the light source unit 112 is implemented as an LD, the LD may be a TO Can type packaged in metal, and may consume 5 mW or more of power, but the embodiment is not limited thereto.

The lens unit 114 may be disposed on the optical axis LX between the light source unit 112 and the first opening OP1 . That is, the lens unit 114 may be disposed on a path through which the first light L1 passes from the light source unit 112 toward the first opening OP1 . The lens unit 114 serves to condense the first light L1 emitted from the light source unit 112 to the first opening OP1 ( L2 ). Also, the lens unit 114 may serve to convert the first light L1 emitted from the light source unit 112 into the parallel light L2 . To this end, the lens unit 114 may include only one lens or a plurality of lenses arranged on the optical axis LX. The material of the lens unit 114 may be the same as a lens applied to a general camera module or an LED module.

The light emitting case 116 accommodates the light source unit 112 and the lens unit 114 , and serves to form the first opening OP1 . In the case of FIG. 1 , the light emitting case 116 is illustrated as being separate from the top portion 172 of the housing 170 , but the embodiment is not limited thereto. That is, the light emitting case 116 may be integrally formed with the top portion 172 of the housing 170 . In this case, the light emitting case 116 may be omitted.

Also, the light emitting case 116 may include a first opening OP1 . In the first opening OP1 , the second light L2 emitted from the light source unit 112 and passing through the lens unit 114 is directed to the scattering unit (or scattering space) SS of the first flow path unit 120 . 3 This is a portion that is emitted as the light L3 and may be disposed on the optical axis LX of the light emitting unit 110 . The scattering unit SS will be described later in detail when the first and second flow path units 120 and 142 are described.

Also, the first opening OP1 may have an area corresponding to a view angle of the first light L1 emitted from the light source unit 112 . In general, the light emission angle of the LED, which may be the light source unit 112, may be about 15° when the luminous intensity is reduced to 50%. As such, since the power of the LED is large at the center, light of a desired intensity may be emitted through the first opening OP1 even if the area of the first opening OP1 is not large. However, when the light emission angle is large, if the area of the first opening OP1 is determined so that the third light L3 having a desired intensity is emitted from the light emitting unit 110, light loss may occur and the light intensity may be weakened. have. Accordingly, the light emission angle may be determined in consideration of this. For example, when the first opening OP1 has a circular planar shape, when the diameter of the first opening OP1 is greater than 15 mm, the size of the particle sensing device 100 increases and optical noise may be caused. have. The diameter of the first opening OP1 may be 2 mm to 15 mm, for example, 3 mm to 10 mm, preferably 4 mm to 6 mm, for example, 5.5 mm, but the embodiment is not limited thereto. .

The first flow path unit 120 may be disposed to intersect the optical axis LX of the light emitting unit 110 under the light emitting unit 110 , and may contain particles of air (hereinafter referred to as 'first air'). ) may provide a first flow path through which it flows. The first air, which may contain particles, is introduced in the IN1 direction toward the first inlet IH1 of the first flow passage 120 and in the OUT1 direction through the first outlet OH1 of the first flow passage 120 . can be emitted. For example, a particle is a particle floating in the first air, and may be dust or smoke, and the embodiment is not limited to a specific shape of the particle.

Particles included in the first air introduced in the IN1 direction through the first inlet IH1 of the first flow path 120 are generated by the third light L3 emitted from the light emitting unit 110 to the first flow path unit ( Scattered by the scattering unit SS of 120 , the scattered fourth light L4 (hereinafter, referred to as 'scattered light') may be provided to the light receiving unit 130 .

The air supply unit 140 may provide particle-filtered air (hereinafter, referred to as 'second air') between the first flow path and the light emitting unit 110 and between the first flow path and the light receiving unit 130 . The second air may be provided in the same direction as a direction in which the first air flows (eg, a y-axis direction). To this end, the air providing unit 140 may include a second flow path unit 142 providing a second flow path through which the second air flows.

The second flow path part 142 providing the second flow path includes a 2-1 flow path part 142-1 forming a 2-1 flow path and a 2-2 flow path part 142 forming a 2-2 flow path. -2), and the 2-1 and 2-2 flow path parts 142-1 and 142-2 are illustrated as being spaced apart from the first flow path part 120, but this This is to explain the concept of the second flow passages 120 and 142 . That is, as will be described later, the second flow path part 142 may be disposed to surround the first flow path part 142 . In this case, the 2-1 and 2-2 flow passages 142-1 and 142-2 may be integrally implemented, and the 2-1 and 2-2 flow passages may form a single second flow passage.

According to an embodiment, the second flow path may be isolated from the first flow path before the scattering unit SS, and may be formed in contact with the first flow path from the scattering unit SS.

In addition, in the case of FIG. 1 , the second flow passage 142 is illustrated as being spaced apart from the light emitting unit 110 and the light receiving unit 130 , respectively, but this is to explain the concept of the particle sensing device 100 according to the embodiment. to be. That is, according to the manner in which the second flow path part 142 is implemented, as in the particle sensing devices 100A to 100C to be described later, the second flow path part 142 is disposed in contact with the light emitting unit 110 and the light receiving unit 130 , respectively. it might be

The fan 180 serves to induce the flow of the first and second air in the first and second flow passages 120 and 142 . That is, the fan 180 serves to constantly maintain the flow rate of at least one of the first and second air in at least one of the first and second flow passages 120 and 142 . To this end, the fan 180 may be disposed adjacent to the first and second flow passages 120 and 142 in the direction in which the first and second air flows (eg, the y-axis direction). For example, as shown in FIG. 1 , the fan 180 includes the first outlet OH1 side of the first channel part 120 and the second and third outlet ports OH2 of the second channel part 142 . , OH3) may be disposed adjacent to the side, but the embodiment is not limited thereto. That is, as long as the flow of air in each of the first and second flow passages 120 and 142 can be induced, the embodiment is not limited to a specific arrangement position of the fan 180 .

For example, in each of the first and second flow passages 120 and 142, the first and second flow passages 120 and 142 are formed so that each of the first and second air maintains a flow rate of 5 ml/sec. It may be implemented or the rotation speed of the fan 180 may be determined, but the embodiment is not limited thereto.

Meanwhile, the light receiving unit 130 serves to incident the fourth light L4 that has passed through the first flow path unit 120 , and for this purpose, it may be disposed on the optical axis LX under the first flow path unit 120 . have. Here, the fourth light L4 passing through the first flow path part 120 may include at least one of scattered light and non-scattered light.

2 shows an exemplary profile of scattered light scattered by particles P.

Referring to FIG. 2 , the scattered light refers to the light scattered by the particles P included in the first air passing through the first flow path 120 through the third light L3 emitted from the light emitting unit 110 . can do. The non-scattered light may refer to light in which the third light L3 emitted from the light emitting unit 110 is not scattered by the particles P passing through the first flow path unit 120 and proceeds to the light receiving unit 130 . have.

The light receiving unit 130 may receive the scattered light and may provide an electrical signal of the received light to the signal converting unit 150 .

The light absorbing unit 102 serves to absorb the fifth light L5 that has passed through the light receiving unit 130 , and for this purpose, it may be disposed on the optical axis LX under the light receiving unit 130 . The light absorbing unit 102 may correspond to a kind of dark room that absorbs and confines unnecessary light (hereinafter, 'main light') that is not received by the light receiving unit 130 and travels in a straight line.

The housing 170 serves to accommodate the light emitting unit 110 , the first and second flow path units 120 and 142 , the light receiving unit 130 , and the light absorbing unit 102 .

For example, the housing 170 may include a top portion 172 , a middle portion 174 , and a bottom portion 176 . The top part 172 is a part that can accommodate the light emitting part 110 , the middle part 174 is a part that can accommodate the first and second flow path parts 120 and 142 and the fan 180 , and the bottom part 176 . may be a portion capable of accommodating the light receiving unit 130 and the light absorbing unit 102 .

In the case of FIG. 1 , the middle portion 174 of the housing 170 and the first and second flow passages 120 and 142 are illustrated as separate, but the embodiment is not limited thereto. According to another embodiment, as in the particle sensing devices 100A to 100C to be described later, the first flow path parts 120A, 120B, 120C and the second flow path part 142 by the middle part 174 of the housing 170 . can be formed.

Hereinafter, embodiments 100A to 100C of the particle sensing device 100 shown in FIG. 1 will be described with reference to the accompanying drawings.

3 is a cross-sectional view of an embodiment 100A of the particle sensing device 100 shown in FIG. 1 . For ease of understanding, the light traveling in FIG. 3 is indicated by a shade (L).

The particle sensing device 100A illustrated in FIG. 3 includes a light absorbing unit 102 , a light emitting unit 110A, a first flow path unit 120A, a light receiving unit 130A, an air providing unit 140A, and housings 172 and 176 . ) and a fan 180 , and the signal conversion unit 150 and the information analysis unit 160 shown in FIG. 1 are omitted.

The light absorbing unit 102, the light emitting unit 110A, the first flow path unit 120A, the light receiving unit 130A, the air providing unit 140A, the housings 172 and 176, and the fan 180 shown in FIG. 3 are The light absorbing unit 102, the light emitting unit 110, the first flow path unit 120, the light receiving unit 130, the air providing unit 140, the housings 172 and 176 and the fan 180 shown in FIG. Since each performs the same function, a description of overlapping parts will be omitted.

Referring to FIG. 3 , the light source unit 112A includes only one light source. The lens unit 114A includes only one lens. The lens 114A is disposed on the optical axis LX between the light source 112A and the first opening OP1 , and serves to condense the light emitted from the light source 112A into the first opening OP1 .

4A is a side cross-sectional view of an intermediate portion FII1 of the 1-1 and 2-1 passages in the first flow passage 120A and the second flow passage 142A shown in FIG. 3 according to an embodiment; FIG. 4B is an enlarged cross-sectional view of part 'A1' shown in FIG. 3 , and for convenience of explanation, FIG. 4A is an intermediate flow path between 1-1 and 2-1 in the first and second flow passages 120A and 142A. Only the portion FII1 and the first and third openings OP1 and OP3 are shown, and illustration of the fan 180 illustrated in FIG. 3 is omitted from FIG. 4B .

Referring to FIGS. 3, 4A, and 4B , the first flow path part 120A includes a first flow path inlet part FI, a 1-1 flow path middle part FII1, a scattering part SS, and a 1-2 flow path part FI. It may include a flow path middle part FII2 and a first flow path outlet part FO. The first flow path inlet FI, the 1-1 flow path intermediate portion FII2, the scattering unit SS, the 1-2 flow path intermediate portion FII2, and the first flow path outlet FO form the first flow path. accomplish

The first flow path inlet FI is a portion into which the first air, which may include particles P, is introduced, and may include a first inlet IH1 and a 1-1 partial flow path. Here, the first inlet IH1 corresponds to the inlet of the first flow path 120A through which air flows in the IN1 direction from the outside, and the 1-1 partial flow path refers to the 1-1 first flow path from the first inlet IH1. Corresponds to a portion of the first flow path formed between the flow path intermediate portions FII1.

The first flow passage outlet FO is a portion through which the first air, which may include particles P, flows out, and may include a first outlet OH1 and a 1-2 partial flow passage. Here, the first outlet OH1 corresponds to an outlet of the first flow path part 120A through which the first air flows out in the OUT1 direction, and the 1-2 partial flow path means the 1-2 flow path middle part FII2. ) corresponds to a portion of the first flow path formed between the first outlet OH1.

The scattering unit SS is positioned on the optical axis LX between the light emitting unit 110A and the light receiving unit 130A and between the first flow path inlet FI and the first flow path outlet FO. The scattering unit SS provides a space in which the light emitted from the light emitting unit 110A is scattered by the particles P. To this end, the scattering unit SS refers to the first opening OP1 in the first flow path units 120 and 120A in a direction in which the light emitting unit 110A and the light receiving unit 130A face each other (eg, the z-axis direction). ) and can be defined as an overlapping region.

The first-first flow path intermediate portion FII1 is positioned between the first flow passage inlet FI and the scattering unit SS, and the 1-2 flow path intermediate portion FII2 is disposed between the scattering unit SS and the first flow passage outlet. It may be located between the parts (FO).

On the other hand, the second flow path part 142A includes a second flow path inlet part FI, a 2-1 flow path intermediate part FII1, an air curtain part AC, and a 2-2 flow path intermediate part FII2. ) and a second flow path outlet FO. The second flow path inlet portion FI, the second flow passage intermediate portion FII1, the air curtain unit AC, the 2-2 flow passage intermediate portion FII2, and the second flow passage outlet portion FO are the second flow passages. make up

The second flow path inlet FI is a portion into which the second air filtered by the particles P is introduced, and may be disposed around the first flow path inlet FI. It may include second and third inlets IH2 and IH3 and a 2-1 partial flow path. Here, the second inlet IH2 corresponds to the inlet of one side 142-1 of the second flow path 142A through which the second air flows in the IN2 direction from the outside, and the third inlet IH3 is IN2 from the outside. It corresponds to the inlet of the other side 142-2 of the second flow path part 142A through which air flows in the direction. The 2-1 partial flow path corresponds to a portion of the second flow path formed between the second and third flow paths intermediate portion FII1 from each of the second and third inlets IH2 and IH3.

The second flow path outlet FO is a portion through which the second air flows, and may be disposed around the first flow path outlet FO, and includes the second and third outlets OH2 and OH3 and the 2-2 partial flow path. may include Here, the second outlet OH2 corresponds to the outlet of one side 142A-1 of the second flow path 142A through which the second air flows out in the OUT1 direction, and the third outlet OH3 is the second air corresponds to the outlet of the other side 142-2 of the second flow path part 142 flowing out in the OUT1 direction, and the 2-2 partial flow path is the second and second flow paths from the 2-2 flow path intermediate part FII2 It corresponds to a portion of the second flow path formed between each of the third outlets OH2 and OH3.

The first and second air curtain units AC1 and AC2 are portions disposed around the scattering unit SS. The first air curtain unit AC1 is positioned between the scattering unit SS and the light emitting unit 110A to space them SS and 110A apart from each other, and the second air curtain unit AC2 is formed between the scattering unit SS and the light emitting unit 110A. It is positioned between the light receiving units 130A to space them (SS, 130A) from each other. Therefore, when the first air, which may contain particles, passes through the scattering unit SS, the air curtain units AC1 and AC2 may block the particles from entering the light emitting unit 110A or the light receiving unit 130A, respectively. have.

The 2-1 th flow path middle part FII1 is disposed around the 1-1 th flow path middle part FII1 and may be positioned between the second flow path inlet part FI and the air curtain parts AC1 and AC2. . The 2-2nd flow path middle part FII1 is disposed around the 1-2nd flow path middle part FII2 and may be positioned between the air curtain parts AC1 and AC2 and the second flow path outlet part FO.

As described above, before the scattering unit SS, the second flow path may be isolated from the first flow path, and the second flow path from the scattering unit SS may be disposed in contact with the first flow path. Accordingly, the first and second flow path inlet portions FI are isolated from each other, the 1-1 and 2-1 flow passage intermediate portions FII1 are isolated from each other, and the air curtain portions AC1 and AC2 and the scattering portion (FII1) are isolated from each other. SS) may be in contact with each other, the first-second and second-second passage intermediate portions FII2 may be in contact with each other, and the first and second passage outlet portions FO may be in contact with each other.

For convenience of description, in FIG. 4B , the intermediate portions FII2 of the first and second and second passages and the first and second outlet portions FO of the first and second passages are denoted by dotted lines in FIG. 4B to distinguish them from the first passage. However, since the second air from the scattering unit SS is combined with the first air, the second flow path through which the second air actually flows from the air curtain units AC1 and AC2 may be different from the dotted line.

Also, in FIGS. 3 and 4 , the second flow path inlet FI of the second flow path is exemplified as being formed by bypassing the top 172 of the housing 170 , but the embodiment is not limited thereto. That is, although not shown, according to another embodiment, the second flow path inlet FI of the second flow path may be formed through, instead of bypassing, the top part 172 of the housing 170 .

According to an embodiment, as shown in FIG. 4A , the 1-1 flow path intermediate part FII1 of the first flow path part 120A is the 2-1 flow path intermediate part FII1 of the second flow path part 142A. ) can be placed in In this case, the inner wall 120A-1 of the 1-1 flow path intermediate portion FII1 defines (or forms) a part of the first flow path, and the outer wall 120A- of the 1-1 flow path intermediate portion FII1 . A portion of the second flow path may be defined (or formed) between 2) and the inner wall 142A-1 of the second-first flow path intermediate portion FII1.

Referring to FIG. 4A , the first flow passage cross-section of the first-first flow passage intermediate portion FII1 of the first flow passage portion 120A and the second flow passage intermediate portion FII1 of the second passage portion 142A are shown. 2 The flow passage cross-section may have a concentric circle shape, but the embodiment is not limited thereto.

After the first air including the particles P is introduced through the first flow path inlet FI, it proceeds to the scattering unit SS through the 1-1 flow path middle portion FII1, and then the first- It is discharged through the first flow path outlet FO through the second flow path intermediate portion FII2. In addition, after the second air, having filtered the particles P, was introduced through the second flow path inlet FI, it proceeds to the air curtain units AC1 and AC2 through the second-first flow path middle portion FII1. Thereafter, it is discharged through the second flow path outlet FO through the 2-2 second flow path intermediate portion FII2. As described above, the fan 180 may be disposed to help the first air and/or the second air flow smoothly through the first and/or second flow passages, respectively. That is, the fan 180 serves to induce the flow of at least one of the first and second air. For example, as shown in FIG. 3 , the fan 180 may be disposed in the first and second flow path outlets FO, and differently from the illustration, the first outlet ( FO) of the first flow path outlet (FO). OH1) and the second and third outlets OH2 and OH3 of the second flow path outlet FO may be disposed adjacent to each other. Alternatively, according to another embodiment, the fan 180 may be disposed within the first and second flow path inlets FI or may be disposed adjacent to the first to third inlets IH1 , IH2 , and IH3 .

While the first air containing the particles P passes through the flow passage 120A, the third light L3 emitted from the first opening OP collides with the particles P in the scattering unit SS, and is shown in FIG. Scattered in the form as shown. At this time, in order to make all the particles P passing through the scattering unit SS collide with the third light L3 emitted from the light emitting unit 110A, the third light ( L3) a first area suitable for forming a light curtain in the scattering unit SS in a direction (eg, x-axis and z-axis) intersecting the direction in which air flows (eg, y-axis direction) The opening OP1 may have it.

In addition, the flow passage cross-sectional area (eg, the area in the x-axis and z-axis directions) of the first flow passage of the first flow passage part 120A is the area of the first opening OP1 (eg, in the x-axis and y-axis directions). area) may be smaller than Also, the sum of the flow passage cross-sectional area of the first flow passage and the flow passage cross-sectional area of the second flow passage (eg, areas in the x-axis and z-axis directions) may be smaller than the area of the first opening OP1 .

For example, referring to FIG. 4B , when the length of the first opening OP1 in the x-axis direction is the same as the length of each of the first flow passage parts 120A in the x-axis direction, the length of the first opening OP1 is The width D1 may be greater than the height D21 of the first flow path part 120A, and the width D1 of the first opening part OP1 is equal to the height D21 of the first flow path part 120A and the second flow path part 120A. It may be greater than the sum of the heights D22 and D23 of the flow passage 142A, that is, the sum of the heights D21, D22, and D23.

Alternatively, referring to FIG. 4B , the first opening OP1 has a circular planar shape, the first flow path part 120A has a circular side cross-sectional shape, and the second flow path part 142A has a circular annular side cross-sectional shape. , the diameter D1 of the first opening OP1 may be larger than the diameter D21 of the first flow path part 120A, and the diameter D1 of the first opening OP1 may be the diameter D2. can be larger than The width (or diameter) D1 of the first opening OP1 may be 2 mm to 15 mm, for example 3 mm to 10 mm, preferably 4 mm to 6 mm, for example 5.5 mm, Examples are not limited thereto.

As described above, when the flow path cross-sectional area of the first flow path part 120A is smaller than the area of the first opening OP1, or when the flow path cross-sectional area of the first flow path part 120A and the flow path cross-sectional area of the second flow path part 142A are When the sum is smaller than the area of the first opening OP1 , the amounts of the first and second air passing through the first and second flow passages 120A and 142A, respectively, increase. Accordingly, the number of particles passing through the first flow path part 120A increases, so that a larger amount of particles can be sensed. In addition, the amount of filtered second air passing through the second flow path part 142A increases, so that the particles entering the scattering part SS do not enter the light emitting part 110A or the light receiving part 130A but into the second air. can be more reliably blocked by

In addition, the flow passage cross-sectional area of the first passage part 120A may be smaller than the beam size of the light emitted from the first opening OP1 . Due to this, the amount of air including the particles P passing through the first flow path part 120A increases, that is, the amount of particles passing through the first flow path part 120A increases, so that a larger amount of particles ( P) can be sensed. As described above, as the amount of the particles P passing through the first flow path part 120A increases, more information on the particles P can be secured. can be analyzed. In order to allow many particles P to pass through, the first flow path part 120 shown in FIG. 1 may have various configurations other than those shown in FIGS. 3 and 4 .

Also, when the particle sensing device is driven, the first flow rate of the first air may be less than or equal to the second flow rate of the second air. This is to block the particles included in the first air from entering the light emitting unit 110A or the light receiving unit 130A by the second air.

5 is a cross-sectional view of another embodiment 100B of the particle sensing device 100 shown in FIG. 1 , and FIG. 6A is a first flow path part 120B and a second flow path part 142B shown in FIG. 5 . It shows a side cross-sectional view according to an embodiment of the 1-1 and 2-1 flow path intermediate portions FII1, and FIG. 6b is an enlarged cross-sectional view of a portion 'A2' shown in FIG. 5, for convenience of explanation, FIG. 6a indicates only the first and second flow passages 120B and 142B and the first and third openings OP1 and OP3, and the fan 180 illustrated in FIG. 5 is omitted from FIG. 6B.

The cross-sectional shapes of the first flow path part 120A shown in FIG. 3 and the first flow path part 120B shown in FIG. 5 are different from each other. In addition, in FIG. 3 , the second flow path part 142A has a cross-sectional shape extending in a constant direction (eg, the y-axis direction) like the first flow path part 120A, while the second flow path part 142A shown in FIG. The flow path portion 142B does not have a cross-sectional shape extending in a predetermined direction. Except for this, since the particle sensing device 100B shown in FIG. 5 is the same as the particle sensing device 100A shown in FIG. 3 , a redundant description will be omitted. For example, the definitions of the scattering unit SS and the air curtain units AC1 and AC2 described above with reference to FIG. 4B may also be applied to the flow path unit 120B shown in FIG. 6B .

3 and 4B, in the direction (eg, the x-axis direction and the z-axis direction) intersecting the direction in which the first air flows (eg, the y-axis direction), the first flow path inlet FI ), the 1-1 flow path intermediate portion FII1 , the scattering unit SS, the 1-2 flow passage intermediate portion FII2 , and the first flow passage outlet portion FO have a constant cross-sectional area.

However, unlike this, the cross-sectional area of the 1-1 flow path intermediate portion FII1 in a direction (eg, x-axis and z-axis direction) intersecting the direction in which the first air flows (eg, y-axis direction) Silver may include a portion that decreases as it approaches the scattering portion SS, and the cross-sectional area of the first-second flow path middle portion FII2 may include a portion that increases as it moves away from the scattering portion SS.

For example, as shown in FIGS. 5 and 6B , in a direction (eg, x-axis and z-axis direction) intersecting the direction in which the first air flows (eg, y-axis direction), the first The cross-sectional area of the -1 flow path middle part FII1 decreases and becomes constant as it approaches the scattering part SS, and the cross-sectional area of the 1-2 flow path middle part FII2 becomes constant as it moves away from the scattering part SS and then increases. can Alternatively, unlike shown in FIGS. 5 and 6B , in a direction (eg, x-axis and z-axis direction) crossing the direction in which the first air flows (eg, y-axis direction), 1-1 The cross-sectional area of the flow path middle part FII1 may continue to decrease as it approaches the scattering part SS, and the cross-sectional area of the first-second flow path middle part FII2 may continue to increase as it moves away from the scattering part SS. .

In addition, unlike shown in FIGS. 3 and 4B , in the direction (eg, the x-axis and the z-axis direction) crossing the direction in which the air flows (eg, the y-axis direction), the first flow path inlet part A cross-sectional area of each of the FI and the first flow passage outlet FO may be greater than a cross-sectional area of the scattering unit SS.

In addition, in the first flow path parts 120A and 120B shown in FIGS. 4B and 6B , the 1-1 flow path intermediate part FII1 (or the 1-2 flow path middle part FII2) and the scattering part SS ) is defined as the 2-1 opening OP21, the area of the first opening OP1 (eg, the area in the x-axis and y-axis directions) is the direction in which the first air flows. The cross-sectional area of the second-first opening OP21 in a direction (eg, the x-axis and the z-axis direction) intersecting (eg, the y-axis direction) may be larger than the cross-sectional area of the second-first opening OP21.

In addition, in the second flow path portions 142A and 1420B shown in FIGS. 4B and 6B , the 2-1 th flow path intermediate portion FII1 (or the 2-2 second flow path intermediate portion FII2) and the air curtain unit ( When the opening regions where AC1 and AC2 communicate with each other are defined as the 2-2 and 2-3 openings OP22 and OP23, respectively, the area of the first opening OP1 (eg, the x-axis and the y-axis) The area in the direction) is in the direction (eg, the x-axis and the z-axis direction) intersecting the direction in which the second air flows (eg, the y-axis direction), the 2-1 to 2-3 openings OP21 , OP22, OP23) may be greater than the sum of the flow passage cross-sectional areas.

For example, referring to FIGS. 4B and 6B , when the length of the first opening OP1 in the x-axis direction is the same as the length of the 2-1 opening OP21 in the x-axis direction, the first opening OP1 ( The width D1 of the OP1 may be greater than the height D41 of the second-first opening OP21. Alternatively, when the length of the first opening OP1 in the x-axis direction is the same as the length in the x-axis direction of each of the 2-1 to 2-3 openings OP21, OP22, and OP23, the first opening OP1 ) may be greater than the sum D4 of the heights D41 , D42 , and D43 of the 2-1 to 2-3rd openings OP21 , OP22 , and OP23 .

Alternatively, referring to FIGS. 4B and 6B , when the first opening OP1 has a circular planar shape and the 2-1 opening OP21 has a circular lateral cross-sectional shape, the diameter of the first opening OP1 ( D1) may be larger than a diameter D41 of the second-first opening OP21. Alternatively, referring to FIGS. 4B and 6B , the first opening OP1 has a circular planar shape, the 2-1 opening OP21 has a circular lateral cross-sectional shape, and the 2-2 and 2-3 openings When OP22 and OP23 have an arc-shaped cross-sectional shape, the diameter D1 of the first opening OP1 may be greater than the sum D4 of the diameters D41 , D42 , and D43 .

When the first flow path part 120B has a cross-sectional shape as shown in FIGS. 5 and 6B , due to a change in the cross-sectional areas of the 1-1 and 1-2 flow path intermediate parts FII1 and FII2, more The particle (P) may pass through the first flow path part (120B), the accuracy of sensing the particle (P) may be increased.

In addition, in the case of FIG. 6A , the 2-1 th flow path intermediate part FII1 is in contact with the upper 2-1 th flow path middle part UFII1 and the second air curtain part AC2 in contact with the first air curtain part AC1. It may include a lower middle part 2-1 of the flow path DFII1. In this case, the upper 2-1 flow path intermediate portion UFII1 and the lower 2-1 flow passage intermediate portion DFII1 are disposed to be spaced apart from each other. For this reason, the first and second air curtain units AC1 and AC2 may be disposed to be spaced apart from each other. On the other hand, in the case of FIG. 4B , the second flow path intermediate portion FII1 is one body without being separated into upper and lower sides, and the first and second air curtain portions AC1 and AC2 are not separated from each other and are one body. to be.

7 is a cross-sectional view of another embodiment 100C of the particle sensing device 100 shown in FIG. 1 , and FIG. 8 is to explain the first and second flow path parts 120C and 142C shown in FIG. As a cross-sectional view showing an enlarged portion of 'A3', the fan 180 shown in FIG. 7 is omitted from FIG. 8 for convenience of explanation.

The cross-sectional shapes of the first flow path part 120A shown in FIG. 3 and the first flow path part 120C shown in FIG. 7 are different from each other. In addition, the second flow path part 142A shown in FIG. 3 has a cross-sectional shape extending in a constant direction (eg, the y-axis direction) like the first flow path part 120A, whereas the second flow path part 142A shown in FIG. The second flow path portion 142C does not have a cross-sectional shape extending in a predetermined direction. Except for this, since the particle sensing device 100C shown in FIG. 7 is the same as the particle sensing device 100A shown in FIG. 3 , a redundant description will be omitted.

3 and 4b, in the direction (eg, the x-axis direction and the z-axis direction) intersecting the direction in which the air flows (eg, the y-axis direction), the first flow path inlet FI, Cross-sectional areas of the first-first flow passage middle portion FII1 , the scattering portion SS, the 1-2 flow passage intermediate portion FII2 , and the first flow passage outlet portion FO are constant.

On the other hand, in the case of FIGS. 7 and 8 , in the direction (eg, the x-axis and the z-axis direction) crossing the direction in which the first air flows (eg, the y-axis direction), the 1-1 flow path The cross-sectional area of the intermediate part FII1 decreases and then increases as it approaches the scattering part SS. In addition, in the direction (eg, the x-axis and the z-axis direction) crossing the direction in which the first air flows (eg, the y-axis direction), the cross-sectional area of the first-2 flow path middle portion FII2 is scattering It decreases and then increases as it goes away from the part SS.

In addition, in the 1-1 intermediate flow path portion FII1 (or the 1-2 intermediate flow passage portion FII2) of the first flow path portion 120C shown in FIG. 8 , the direction in which the first air flows intersects When the opening region having the smallest cross-sectional area in the direction is defined as the 2-1 opening OP21, the area of the first opening OP1 (eg, the area in the x-axis and y-axis directions) is The cross-sectional area of the second-first opening OP21 in a direction (eg, the x-axis and z-axis direction) crossing the flow direction (eg, the y-axis direction) may be larger than the cross-sectional area of the second opening OP21.

In addition, in the 2-1 th intermediate flow path portion FII1 (or the 2-2 second intermediate flow path portion FII2) of the second flow path portion 142C shown in FIG. When the opening region having the smallest cross-sectional area in the direction is defined as the 2-2 and 2-3 openings OP22 and OP23, respectively, the area of the first opening OP1 (eg, in the x-axis and y-axis directions) The area of ) is in the direction (eg, the x-axis and the z-axis direction) intersecting the direction (eg, the y-axis direction) in which the first and second air flows, the first and second openings 2-1 to 2-3 It may be greater than the sum of the cross-sectional areas of the openings OP21 to OP23.

For example, referring to FIG. 8 , it is assumed that the length in the x-axis direction of the first opening OP1 is the same as the length in the x-axis direction of each of the 2-1 to 2-3 openings OP21, OP22, and OP23. In this case, the width D1 of the first opening OP1 may be greater than the height D41 of the 2-1 opening OP21, and the 2-1 to 2-3 openings OP21, OP22, and OP23. ) may be greater than the sum D4 of the heights D41, D42, and D43.

Alternatively, referring to FIG. 8 , the first opening OP1 has a circular planar shape, the 2-1 opening OP21 has a circular lateral cross-sectional shape, and the 2-2 and 2-3 openings OP22 and OP23 ) has a circular annular cross-sectional shape, the diameter D1 of the first opening OP1 may be greater than the sum D4 of the diameters D41 , D42 , and D43 .

For example, the height D4 of the second opening OP2 shown in FIGS. 4b , 6b and 8 may be between 1 mm and 10.0 mm, for example between 1 mm and 5.0 mm, preferably between 1 mm and 2.0 mm For example, it may be 2 mm, but the embodiment is not limited thereto. As described above, according to the embodiment, since the height D4 of the second opening OP2 is reduced, the size of the entire particle sensing apparatuses 100A to 100C may be reduced.

In addition, in order to allow more particles to pass through the first flow path parts 120 : 120A, 120B, and 120C, there should be no change in the volume of the flow rate of the first air passing through the first flow path part 120 . To this end, when a double nozzle (DN: Double Nozzle) structure is formed by the second opening OP2 as shown in FIGS. 7 and 8 , the flow rate of the first air passing through the first flow path 120C Even when there is a change in the volume of , the flow rate of the first air can be adjusted to a degree to be easily measured, so that the accuracy of sensing the particles P can be increased. For example, since a bottleneck is created by the double nozzle structure, more particles P can pass through the first flow path part 120C, so that the accuracy of sensing the particles P can be increased.

The structures of the first flow passages 120A, 120B, and 120C shown in FIGS. 3 to 8 are only examples. That is, if more first air can be introduced through the first flow path parts 120A, 120B, and 120C, the embodiment is not limited to a specific example of the first flow path part 120 .

In addition, while the first flow path part 120A shown in FIG. 4B has the same flow path cross-sectional area at any point on the first flow path, in the case of the first flow path parts 120B and 120C shown in FIGS. 6B and 8 , the first flow path part 120A 1 All points on the flow path do not have the same flow path cross-sectional area.

On the other hand, the second flow passages 142A, 142B, and 142C illustrated in FIGS. 4B, 6B, and 8 may have a constant flow passage cross-sectional area at any point on the second flow passage. However, the embodiment is not limited thereto. That is, the structures of the second flow passages 142A, 142B, and 142C shown in FIGS. 3 to 8 are only examples. That is, if the second air flows through the second flow passages 142A, 142B, and 142C, the particles contained in the first air can be blocked from entering the light emitting unit 110A or the light receiving unit 130A. The example is not limited to the specific example of the second flow path part 142 .

In addition, as illustrated in FIGS. 6B and 8 , in a direction (eg, x-axis and z-axis direction) crossing the direction in which the first air flows (eg, y-axis direction), the first inlet port A cross-sectional area of each of the IH1 and the first outlet OH1 may be greater than an area of the first opening OP1 and greater than a cross-sectional area of the second-first opening OP21.

In addition, as illustrated in FIGS. 6B and 8 , in the direction (eg, the x-axis and the z-axis direction) intersecting the direction in which the first and second air flow (eg, the y-axis direction), A sum of flow passage cross-sectional areas of the first to third inlets IH1 , IH2 , and IH3 may be greater than an area of the first opening OP1 and greater than a cross-sectional area of the second opening OP2 .

Alternatively, in the direction (eg, the x-axis and the z-axis direction) intersecting the direction in which the air flows (eg, the y-axis direction), the 1-1 partial flow path of the first flow path inlet FI and The widest cross-sectional area of each of the first-second partial passages of the first passage outlet FO may be greater than the area of the first opening OP1 and greater than the cross-sectional area of the second-first opening OP21.

Alternatively, in the direction (eg, the x-axis and the z-axis direction) intersecting the direction in which the air flows (eg, the y-axis direction), the first and second flow path inlets FI's 1-1 The sum of the widest cross-sectional areas of each of the partial flow passages and the 2-1 partial flow passages or the sum of the widest cross-sectional areas of each of the 1-2 partial flow passages and the 2-2 partial flow passages of the first and second flow passage outlets FO is It may be larger than the area of the first opening OP1 and larger than the cross-sectional area of the second opening OP2 .

For example, when the x-axis length of each of the first inlet IH1 and the first outlet OH1 is the same as the x-axis length of each of the first opening OP1 and the 2-1 opening OP21, the first The height D21 in the z-axis direction of each of the inlet IH1 and the first outlet OH1 is greater than the width D1 in the y-axis direction of the first opening OP1, and the 2-1 opening OP21 may be greater than the height D41 in the z-axis direction.

In addition, the x-axis length of each of the first to third inlets (IH1, IH2, IH3) and the first to third outlets (OH1, OH2, OH3) and the first opening (OP1) and 2-1 to second- When the x-axis length of each of the three openings OP21, OP22, and OP23 is the same, the z-axis of each of the first to third inlets IH1, IH2, IH3 and the first to third outlets OH1, OH2, OH3 The sum D2 of the heights D21, D22, and D23 in the direction is greater than the width D1 of the first opening OP1 in the y-axis direction, and the z of the 2-1 openings OP21, OP22, and OP23. It may be greater than the sum D4 of the heights D41, D42, and D44 in the axial direction.

D2 may be 1 mm to 15 mm, for example, 2 mm to 8 mm, preferably 3 mm to 4 mm, for example, 3.5 mm, but the embodiment is not limited thereto. Further, the sum of the heights (or diameters) of the first to third outlet ports OH1, OH2, OH3 is 5 mm to 25 mm, for example 8 mm to 15 mm, preferably 10 mm to 12 mm, for example. For example, it may be 11 mm, but the embodiment is not limited thereto.

Or, for example, when the x-axis length of each of the first inlet IH1 and the first outlet OH1 is the same as the x-axis length of each of the first opening OP1 and the 2-1 opening OP21, The highest height in the z-axis direction of each of the 1-1 partial flow passage and the 1-2 partial flow passage is greater than the width D1 in the y-axis direction of the first opening OP1 and the second opening OP21 is It may be greater than the height D41 in the z-axis direction.

In addition, for example, the x-axis length of each of the first to third inlets IH1 , IH2 , IH3 and the first to third outlet ports OH1 , OH2 , OH3 and the first opening OP1 and 2-1 When the x-axis length of each of the 2-3 openings OP21, OP22, and OP23 is the same, in the z-axis direction of the 1-1, 1-2, 2-1, and 2-2 partial flow paths, respectively. The sum of the highest heights is greater than the width D1 of the first opening OP1 in the y-axis direction, and the height ( It may be greater than the sum D4 of D41, D42, and D43.

Meanwhile, the air providing unit 140 illustrated in FIG. 1 may further include an air filtering unit 144 . The air filtering unit 144 filters particles from the first air introduced through the input terminal IN1, and outputs the filtered air as the second air. For example, as shown in Fig. 3 or 7, the air filtering unit 144A may include only one outlet for outputting the second air, and as shown in Fig. 5, the air filtering unit 144B is It may include two outlets for outputting the second air.

On the other hand, the light receiving unit 130 may have various structures in order to accurately detect the light scattered from the particles (P). The light receiving unit 130A shown in FIGS. 3, 5 and 7 corresponds to an embodiment of the light receiving unit 130 shown in FIG. 1 .

9 is an enlarged cross-sectional view of part 'B' shown in FIG. 3 .

3 and 9 , the light receiving unit 130A may include a light transmitting member 132 and a light sensing unit 134 . In addition, the light receiving unit 130A may further include the light guide unit 136A, but in some cases, the light guide unit 136A may be omitted.

The light-transmitting member 132 may be implemented with a material that can transmit light, for example, it may be implemented with glass. The light transmitting member 132 may include a first surface 132-1 and a second surface 132-2. The first surface 132-1 corresponds to the upper surface (ie, the top surface) of the light-transmitting member 132 facing the scattering unit SS, and the second surface 132-2 is the first surface 132-1. As a surface opposite to , it may correspond to a lower surface (ie, a bottom surface) of the light-transmitting member 132 .

The light sensing unit 134 and the light guide unit 136A may be disposed around the optical axis of the light transmitting member 132 . The light sensing unit 134 and the light guide unit 136A may be disposed on opposite surfaces of the light transmitting member 132 . For example, as shown in FIG. 9 , the light sensing unit 134 is disposed on the second surface 132 - 2 of the light transmitting member 132 , and the light guide unit 136A is disposed on the light transmitting member 132 . It may be disposed on the first surface 132-1. Alternatively, unlike shown in FIG. 9 , the light sensing unit 134 is disposed on the first surface 132-1 of the light-transmitting member 132 , and the light guide unit 136A is formed on the second surface of the light-transmitting member 132 . It may be disposed on the surface 132 - 2 . Hereinafter, the light sensing unit 134 is disposed on the second surface 132 - 2 of the light transmitting member 132 , and the light guide unit 136A is disposed on the first surface 132-1 of the light transmitting member 132 . However, the following description can be applied even in the opposite case.

The light sensing unit 134 is disposed on the periphery of the optical axis LX under the light transmitting member 132 , and after being scattered by the particles P at the scattering unit SS, the light incident through the light receiving unit OP3 . can be sensed. The light-receiving incident portion will be described later.

FIG. 10A is a plan view of an embodiment of the photodetector shown in FIG. 9 , and FIG. 10B is a cross-sectional view of the photodetector shown in FIG. 10A taken along the line J-J′ according to an embodiment.

10A and 10B , the light sensing unit 134A may include a central portion (or a light transmitting region) 134 - 1 and a photodiode 134 - 2 . The central portion 134-1 is a region defined by the inner edge of the photodiode 134-2, and the optical axis ( LX) and may be implemented with a light-transmitting material. For example, the central portion 134 - 1 may be made of glass.

Also, referring to FIG. 10B , the photodiode 134 - 2 may include a first electrode 1010 , a semiconductor layer 1020 , and a second electrode 1030 . At least a portion of the first electrode 1010 , the semiconductor layer 1020 , and the second electrode 1030 may overlap in a thickness direction (eg, a z-axis direction).

The semiconductor layer 1020 may include a PN, PIN, or Avalanche diode in the form of a thin film, and may include a P layer 1022 , an active layer 1024 , and an N layer 1026 when configured as a PIN diode. Here, the active layer 1024 may include an intrinsic semiconductor layer. The P layer 1022 and the N layer 1026 may have a thickness of 15 nm to 20 nm in the z-axis direction, and the active layer 1024 may have a thickness of 200 nm to 600 nm in the z-axis direction. In addition, the first electrode 1010 may have light-transmitting properties, and may include a material such as GAZO, GZO, and ITO, and the second electrode 1030 may include a metal material such as Al, Ti, TiN, Ag, Au, etc. may include Accordingly, the first electrode 1010 may be referred to as a “transparent electrode” and the second electrode 1030 may be referred to as a “metal electrode”. The thickness of the first electrode 1010 and the second electrode 1030 in the z-axis direction may be 100 μm to 1 mm. Of course, the thickness of each layer described above is exemplary and the embodiment is not limited thereto, and the photodiode 134-2 having the above-described structure may be manufactured by deposition or printing.

Also, the central portion 134 - 1 may cover the light entrance OPL of the light absorbing portion 102 . As such, when the central portion 134 - 1 covers the light inlet OPL, the penetration of foreign substances into the light absorbing portion 102 can be prevented, and the particles P passing through the scattering portion SS are absorbed by the light. It is possible to prevent the entry into the portion 102, the flow of the particles (P) in the flow passage portion 120 is smooth and the measurement error may also be reduced.

The light transmitting member 132 may serve as a substrate for the photodiode 134 - 2 . When the photodiode 134 - 2 is disposed on the second surface 132 - 2 of the light transmitting member 132 , the upper surface of the first electrode layer 1010 is the second surface 132 - 2 of the light transmitting member 132 . ) is encountered. In contrast, when the photodiode 134 - 2 is disposed on the first surface 132-1 of the light transmitting member 132 , the bottom surface of the second electrode layer 1030 is the first surface 132 of the light transmitting member 132 . -1) is encountered.

The central portion 134 - 1 is positioned on the optical axis LX to pass the main light passing through the scattering portion SS to the light absorption portion 102 , and the semiconductor layer 1020 of the photodiode 134 - 2 . and a region where the second electrode 1030 is not disposed. According to an embodiment, when the first electrode 1010 extends in the J direction (ie, the optical axis direction) of FIG. 10B , the central portion 134 - 1 may include at least a portion of the first electrode 1010 . For example, when the first electrode 1010 extends to the optical axis and has a circular planar shape, the first electrode 1010 may be included in the entire central portion 134 - 1 .

In addition, when the photodiode 134 - 2 is disposed on the second surface 132 - 2 of the light transmitting member 132 , damage to the photodiode 132 - 2 due to foreign substances can be prevented.

The photodiode 134-2 is disposed around the central portion 134-1, and serves to sense light scattered by the particles P. The photodiode 134-2 corresponds to an active region that absorbs light in a general photodiode structure.

For example, the photodiode 134-2 may detect light in a wavelength band of 380 nm to 1100 nm, but the embodiment is not limited to a specific wavelength band detectable by the photodiode 134-2. In addition, so that scattered light can be well sensed, the photodiode 134-2 may have a sensitivity of 0.4 A/W in a wavelength band of 660 nm or a sensitivity of 0.3 A/W in a wavelength band of 450 nm. is not limited thereto.

Referring to FIG. 10A , the width W1 of the light sensing unit 134A may be 5 mm to 20 mm, for example, 7 mm to 15 mm, preferably 8 mm to 10 mm, but the embodiment is limited thereto. doesn't happen

In addition, the width W2 of the central portion 134-1 may be 3 mm to 18 mm, for example, 5 mm to 13 mm, preferably 7 mm to 9 mm, but the embodiment is not limited thereto.

In addition, the width W3 on the plane of the photodiode 134-2 may be 0.1 mm to 5 mm, for example, 1 mm to 3 mm, preferably 1.5 mm to 2.5 mm, but the embodiment is not limited thereto. does not

The planar shape of the photodiode 134 - 2 shown in FIG. 10A is a circular annular shape, but the embodiment is not limited thereto. For example, if the photodetector 134 may include the central portion 134-1, the photodiode 134-2 may have various planar shapes. For example, although not shown, the planar shape of the photodiode 134-2 may be a rectangular ring shape, a square ring shape, a polygonal ring shape such as a triangular ring shape, or an elliptical ring shape.

FIG. 11 shows a planar shape of another embodiment 134B of the light sensing unit 134 shown in FIG. 9 .

The photodiode 134 - 2 may include a plurality of sensing segments spaced apart from each other on the same plane. For example, as illustrated in FIG. 11 , the photodiode 134-2 may include a plurality of sensing segments 134-21, 134-22, 134-23, and 134-24 spaced apart from each other. .

Also, the plurality of sensing segments 134-21 , 134-22 , 134-23 , and 134-24 may be disposed to be spaced apart from each other at equal intervals or at different intervals. For example, as the spaced distance G of the plurality of sensing segments 134-21 , 134-22 , 134-23 , and 134-24 increases, a signal level may increase to increase design freedom. For example, the gap G may be 0.01 mm to 1 mm, for example, 0.1 mm to 0.5 mm, preferably 0.15 mm to 0.25 mm, but the embodiment is not limited thereto.

Also, the plurality of sensing segments 134-21 , 134-22 , 134-23 , and 134-24 may have the same planar area or different planar areas.

Also, the light sensing unit 134B may be symmetrically disposed on a plane, but the embodiment is not limited thereto. According to another embodiment, the light sensing unit 134B may be asymmetrically disposed on a plane.

Also, the plurality of sensing segments 134-21 , 134-22 , 134-23 , and 134-24 may be disposed symmetrically or asymmetrically on a plane.

For the widths W1, W2, and W3 shown in FIG. 11, the contents described in FIG. 10A may be applied.

For example, like the photodiode 134-2, each of the plurality of sensing segments 134-21, 134-22, 134-23, and 134-24 may detect light in a wavelength band of 380 nm to 1100 nm. , the embodiment is not limited to a specific wavelength band that can be detected by the plurality of sensing segments 134-21, 134-22, 134-23, and 134-24. In addition, each of the plurality of sensing segments 134-21 , 134-22 , 134-23 , 134-24 has a sensitivity of 0.4A/W in a wavelength band of 660 nm, or 450 so that the scattered light can be sensed well. It may have a sensitivity of 0.3 A/W in nm, but the embodiment is not limited thereto.

When the photodiode 134-2 is disposed to be spaced apart from the plurality of detection segments 134-21, 134-22, 134-23, and 134-24, the information analyzer 160 may 21, 134-22, 134-23, 134-24), the shape of the particle can be predicted using the relative size of the sensed result.

When the shape of the particle P is symmetrical, for example, a spherical shape, the intensity of scattered light detected by the plurality of sensing segments 134-21 , 134-22 , 134-23 , and 134-24 is equal to each other. As such, when the intensity of light detected by the plurality of sensing segments 134-21, 134-22, 134-23, and 134-24 is the same, the information analysis unit 160 determines that the particle P has a symmetrical shape. You can decide to have On the other hand, when the shape of the particle P is asymmetric, for example, non-spherical, the intensity of scattered light sensed by the plurality of sensing segments 134-21 , 134-22 , 134-23 , and 134-24 is different from each other. As such, when the intensity of the light detected by the plurality of sensing segments 134-21 , 134-22 , 134-23 , and 134-24 is different from each other, the information analysis unit 160 determines that the particle P has an asymmetric shape. it can be decided that

Of course, the number of divided shapes of the plurality of sensing segments may vary in order to predict various shapes of particles.

Like the light source 112A of the light emitting unit 110A, the above-described packaging of the photodiodes 134-2 and 134-21 to 134-24 of the light receiving unit 130A may be implemented as an SMD type or a lead type. However, the embodiment is not limited to a specific packaging type of the photodiodes 134-2 and 134-21 to 134-24.

Meanwhile, the light receiving unit may be disposed between the scattering unit SS and the light receiving unit 130A to adjust the amount of light incident to the light receiving unit 130A. To this end, as shown in FIGS. 3, 5, and 7 , the light receiving unit may include a third opening OP3 disposed on the optical axis LX.

The third opening OP3 has a suitable area (eg, the x-axis and the y area in the axial direction).

The scattering unit SS may be in contact with the plurality of openings. That is, the scattering unit SS communicates with the light emitting unit 110A through the first opening OP1 , and the 1-1 and 2-1 channel intermediate portions FII1 (or 1-2 and the second −2 may communicate with the middle portion FII2 of the flow path) and the second opening OP2 , and may communicate with the light receiving unit 130A through the third opening OP3 .

For example, among the light scattered by the particles P in the scattering unit SS, when the distance from the center of the scattering unit SS to the fifth opening OP5 is 12° left and right with respect to the optical axis LX, that is, , when the predetermined angle θ shown in FIGS. 3, 5 and 7 is 24°, 20% of the total light scattered from the particles P may be incident to the light receiving unit 130A, and the predetermined angle θ When is 60° (ie, 30° left and right with respect to the optical axis LX), 50% of the total light scattered from the particles P may be incident on the light receiving unit 130A. Considering this, according to the embodiment, the third opening OP3 has a left-right sum of the light scattered by the particles P based on the optical axis LX, that is, the predetermined angle θ is 24° to 60°. For example, it may have an area suitable for light in a range of 30° left and right with respect to the optical axis LX to be incident on the light receiving unit 130A. As described above, it can be seen that the amount of light incident to the light receiving unit 130A can be adjusted by adjusting the area of the third opening OP3 .

Also, referring to FIGS. 4B , 6B and 8 , the area of the third opening OP3 (eg, the area in the x-axis and y-axis directions) is the area of the first opening OP1 (eg, area in the x-axis and y-axis directions). For example, when the third opening OP3 has a circular planar shape and the diameter D3 of the third opening OP3 is greater than 10 mm, the photodiodes 134-2 and 134-21 to 134-24 As more scattered light than the area of , may be introduced, optical noise may occur. In addition, when the diameter D3 of the third opening OP3 is less than 2 mm, the amount of scattered light received from the photodiodes 134-2 and 134-21 to 134-24 is reduced, and thus the photodiodes 134-2 and 134-21 to 134-24), the magnitude of the detected signal may be small. Accordingly, the diameter D3 of the third opening OP3 may be 1 mm to 12 mm, for example, 1 mm to 6 mm, preferably 2 mm to 4 mm, for example, 3 mm. not limited

Meanwhile, referring again to FIG. 9 , the light guide unit 136A serves to guide the light scattered by the scattering unit SS to the light sensing unit 134 . To this end, for example, the light guide part 136A may include inner partition walls 136-1 and 136-2 and outer partition walls 136-3 and 136-4. If the inner partition walls 136-1 and 136-2 have a circular planar shape, the inner partition walls 136-1 and 136-2 are integral, and the outer partition walls 136-3 and 136-4 have a circular planar shape. In the case of having the outer partition walls 136-3 and 136-4 may be integral.

The inner partition walls 136 - 1 and 136 - 2 have a fourth opening OP4 overlapping the light inlet OPL of the light absorbing unit 102 in a direction parallel to the optical axis LX (eg, the z-axis direction). can be defined. In the inner partition walls 136 - 1 and 136 - 2 , the scattered light passing through the third opening OP3 proceeds to the fifth opening OP5 , and the main light passing through the third opening OP3 is transmitted through the fourth opening. It can have a height H1 that allows it to proceed to (OP4). That is, the inner partition walls 136 - 1 and 136 - 2 serve to separate the main light and the scattered light.

The height H1 of the inner partition walls 136-1 and 136-2 may be 1 mm to 15 mm, for example 2 mm to 10 mm, preferably 3 mm to 6 mm, for example 5 mm, but in practice Examples are not limited thereto.

The outer barrier ribs 136 - 3 and 136 - 4 form a fifth opening OP5 overlapping the photodiode 134 - 2 in a direction parallel to the optical axis LX (eg, the z axis direction) to form the inner barrier rib 136 . -1, 136-2) can be defined together.

The width W4 of the fifth opening OP5 may be 0.1 mm to 6 mm, for example, 0.5 mm to 3 mm, preferably 0.8 mm to 1.5 mm, for example, 1 mm, but the embodiment is not limited thereto. does not

As described above, when the inner partition walls 136-1 and 136-2 and the outer partition walls 136-3 and 136-4 are disposed, as indicated by arrows in FIG. 3 , they enter the third opening OP3. The scattered light may travel to the photodiode 134 - 2 of the light sensing unit 134 , and the main light incident through the third opening OP3 may travel toward the light absorption unit 140 .

Meanwhile, the light receiving unit 130A may further include the sensing support 138 , but in some cases, the sensing support 138 may be omitted.

The sensing support 138 serves to support the light sensing unit 134 , and may be implemented separately from the bottom part 176 of the housing 170 as shown in FIG. 3 , or as shown in FIG. 3 , the housing 170 . ) may be implemented integrally with the bottom portion 176 of the.

Meanwhile, according to an embodiment, as illustrated in FIG. 3 , the light absorbing part 102 may include an absorbing case 102A, a protrusion 102B, and a protrusion 102C. The absorption case 102A defines an optical entrance OPL through which the light passing through the light receiving unit 130A is incident, and serves to receive the main light passing through the light receiving unit 130A. The width of the light entrance OPL (eg the width in the y-axis direction) may be 2 mm to 15 mm eg 3 mm to 10 mm preferably 4 mm to 6 mm eg 5.5 mm However, the embodiment is not limited thereto.

To this end, the inner wall of the absorption case 102A may be coated with a material having light absorption. In the case of FIG. 3 , the absorption case 102A and the bottom portion 176 of the housing 170 are illustrated as being separate, but the embodiment is not limited thereto. That is, the bottom portion 176 of the housing 170 and the absorption case 102A may be integrally formed. That is, the bottom portion 176 of the housing 170 may also serve as the absorption case 102A.

Also, the protrusion 102B may have a shape protruding from the bottom surface of the absorption case 102A toward the light inlet OPL. In addition, the width of the protrusion 102B may become narrower toward the optical inlet OPL from the bottom surface of the absorption case 102A. For example, as illustrated in FIG. 3 , the protrusion 102B may have a circular (pendulum) cross-sectional shape, but the embodiment is not limited thereto. In this way, when the protrusion 102B is disposed, the main light incident to the optical entrance OPL is reflected from the inner wall of the absorption case 102A and escapes to the optical entrance OPL, and the optical entrance OPL is prevented. By reflecting the main light incident through the absorbing case portion 102A to the inner wall, the absorption rate of the main light incident to the light entrance OPL may be improved. In addition, in order to further improve the light absorption rate, the light absorption portion 102 may include a plurality of projections 102C disposed on the inner wall thereof. In this way, when the plurality of protrusions 102C are formed, the main light incident through the light entrance OPL may be destroyed while colliding with the protrusions 102C.

12 is a block diagram of an embodiment 160A of the information analysis unit 160 shown in FIG. 1 , and may include an amplifier 162 and a control unit 164 .

The amplifying unit 162 may amplify an electrical signal incident from the light receiving unit 130A (or the signal converting unit 150 ) through the input terminal IN3 , and output the amplified result to the control unit 164 . The control unit 164 compares the analog signal amplified by the amplifying unit 162 with a pulse width modulation (PWM) reference signal, and the number, concentration, size or shape of the particles P using the comparison result Analyze at least one of them, and output the analyzed result through the output terminal OUT2.

The particle sensing device according to the above-described embodiment may be applied to home appliances and industrial air purifiers, air purifiers, air cleaners, air coolers, and air conditioners, and air quality management systems for buildings, indoor/outdoor vehicles It can be applied to an air conditioning system or an indoor air quality measurement device for a vehicle. However, the particle sensing apparatuses 100 and 100A to 100C according to the embodiment are not limited to these examples and may be applied to various fields, of course.

An air purifier according to an embodiment including the particle sensing device according to the above embodiment will be described with reference to the accompanying drawings.

13 is a schematic cross-sectional view of the air purifier 400 according to the embodiment.

The air purifier 400 shown in FIG. 13 may include a body 410 , a cover 420 , an air filter 430 , and a particle sensing device 440 . Here, the particle sensing device 440 may correspond to the aforementioned particle sensing devices 100: 100A to 100C.

The body 400 serves to accommodate the air filtering unit 430 and the particle sensing device 440 . The first air A1 that may contain particles is introduced through the opening 422a of the cover 420 . Thereafter, the particles included in the introduced first air A1 are filtered by the air filtering unit 430 . Thereafter, the second air (A2) from which the particles are filtered may flow out through the outlet 450 of the body 410 to the outside. In this case, the particle sensing device 440 may provide the second air A2 filtered by the air filtering unit 430 to the second flow path unit 142 . In this way, since the air filtering unit 430 performs the role of the air filtering unit 144 included in the aforementioned particle sensing devices 100:100A to 100C, the particle sensing device 100:100A to 100C filters the air. Part 144 is not required.

Hereinafter, the particle sensing apparatus according to the comparative example and the particle sensing apparatus 100 and 100A to 100C according to the embodiment will be compared and described as follows. The particle sensing device according to the comparative example is a case in which the air providing unit 140 is omitted from the particle sensing devices 100: 100A to 100C according to the embodiment. That is, in the case of the particle sensing device according to the comparative example, the area occupied by the second flow path parts 142: 142A, 142B, and 142C of the particle sensing device according to the embodiment corresponds to the first flow path part.

14 is a photograph of a state in which the first air flows through the first flow path in the particle sensing device according to the comparative example, and FIG. 15 is the first and second air in the particle sensing device 100 and 440 according to the embodiment. It is a photograph of a state that the flow of the first and second flow passages, respectively.

Referring to FIG. 14 , while the first air passes through the first flow path, particles included in the first air may enter the light emitting unit 110A or the light receiving unit 130A. When particles enter the light emitting unit 110A or the light receiving unit 130A, the light emitting unit 110A or the light receiving unit 130A is contaminated, and information on the particles may not be accurately sensed.

On the other hand, referring to FIG. 15 , the second air flows through the second flow path part 142 while surrounding the first flow path part 120 through which the first air flows. As such, when the second air flows at a faster flow rate than the first air while surrounding the first air, each of the light emitting unit 110A and the light receiving unit 130A is formed by the second air in the air curtain units AC1 and AC2. This allows protection from primary air. That is, particles contained in the first air cannot enter toward the light emitting unit 110A or the light receiving unit 130A.

Accordingly, in the case of the particle sensing device and the air purifier including the same according to the embodiment, it is possible to reduce the inconvenience of periodically/aperiodically cleaning the part contaminated by the particles in the light emitting unit 110A or the light receiving unit 130A. In addition, since the concern that the light emitting unit 110A/light receiving unit 130A is contaminated by the particles is eliminated, it is possible to accurately obtain sensing information about the particles.

In the above, the embodiment has been mainly described, but this is merely an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are not exemplified above in the range that does not depart from the essential characteristics of the present embodiment. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

100, 100A to 100C, 440: particle sensing device 102: light absorption unit
110: light emitting part 120: first flow path part
130: light receiving unit 140: air providing unit
142, 142A, 142B, 142C: second flow passage 144, 430: air filtering unit
150: signal conversion unit 160: information analysis unit
170: housing 180: fan
410: body 420: cover
430: air filtering unit

Claims (13)

a light emitting unit emitting light;
a first flow path that is disposed under the light emitting part to intersect the optical axis of the light emitting part and provides a first flow path through which first air including particles flows;
a light receiving unit disposed on the optical axis under the first flow path and receiving light passing through the first flow path;
an air supply unit providing the second air, in which the particles are filtered, in the same direction as the flow direction of the first air between the first flow path and the light emitting unit and between the first flow path and the light receiving unit; and
and a light absorbing unit disposed on the optical axis under the light receiving unit to absorb light that is not received by the light receiving unit and travels in a straight line. The method of claim 1, wherein the first flow path part
a first flow path inlet through which the first air is introduced;
a first passage outlet through which the first air is discharged;
a scattering unit positioned on the optical axis between the first passage inlet and the first passage outlet and between the light emitting unit and the light receiving unit to scatter the particles;
a first-first flow passage intermediate portion positioned between the first flow passage inlet and the scattering portion; and
and a 1-2 flow path middle part located between the scattering part and the first flow path outlet part;
The first flow path inlet part, the 1-1 flow path middle part, the scattering part, the 1-2 flow path middle part, and the first flow path outlet part form the first flow path. The method of claim 2, wherein the air supply unit
and a second flow path that is isolated from the first flow path before the scattering unit, is in contact with the first flow path from the scattering unit, and provides a second flow path through which the second air flows. 4. The method of claim 3, wherein the second flow path part
a second passage inlet through which the second air is introduced and disposed around the first passage inlet;
a second flow path outlet part through which the second air flows out and disposed around the first flow path outlet part;
an air curtain part disposed around the scattering part to separate the upper scattering part from the light receiving part and to separate the scattering part from the light emitting part;
a 2-1 passage intermediate portion disposed around the 1-1 passage intermediate portion; and
and a 2-2 flow path intermediate portion disposed on the periphery of the 1-2 flow passage intermediate portion,
The second flow path inlet part, the 2-1 flow path middle part, the air curtain part, the 2-2 flow path middle part, and the second flow path outlet part form the second flow path,
The first and second flow path inlets are isolated from each other, the 1-1 and 2-1 flow path intermediate portions are isolated from each other, the air curtain unit and the scattering unit are in contact with each other, and 1-2 and 2-2 A particle sensing device in which a middle portion of a flow path is in contact with each other, and the first and second flow passage outlets are in contact with each other. 5. The method of claim 4, wherein the 1-1 flow passage intermediate portion is disposed in the 2-1 passage intermediate portion,
The inner wall of the middle part of the 1-1 flow path forms a part of the first flow path,
A particle sensing device for forming a part of the second flow path between an outer wall of the 1-1 middle portion of the flow passage and an inner wall of the 2-1 middle portion of the flow passage. The particle sensing device of claim 5 , wherein a cross-section of the first flow path in the middle of the 1-1 flow path and a cross-section of the second flow path in the middle of the 2-1 flow path are concentric. The method of claim 4, wherein the air curtain unit
a first air curtain unit positioned between the light emitting unit and the scattering unit; and
and a second air curtain unit positioned between the scattering unit and the light receiving unit and spaced apart from the first air curtain unit. 8. The method of claim 7, wherein the 2-1 middle portion of the flow path
an upper second 2-1 flow path intermediate portion in contact with the first air curtain unit; and
and a lower middle 2-1 passage spaced apart from the upper 2-1 passage middle portion in contact with the second air curtain portion. 5. The method of claim 4, wherein the light emitting unit
light source unit; and
and a first opening disposed on the optical axis for emitting light emitted from the light source unit toward the scattering unit. The particle sensing device of claim 9 , wherein a cross-sectional area of the first passage is smaller than an area of the first opening. The particle sensing device of claim 9 , wherein a sum of the flow passage cross-sectional area of the first flow passage and the flow passage cross-sectional area of the second flow passage is smaller than an area of the first opening. The particle sensing device of claim 1 , wherein when the particle sensing device is driven, the first flow rate of the first air is less than or equal to the second flow rate of the second air. The particle sensing device of claim 3 , wherein the flow passage cross-sectional area of the second flow passage part at an arbitrary point on the second flow passage is constant.

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