Patent Publication Number: US-2020292437-A1

Title: Particle detecting device

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to a particle detecting device, and more particularly to a particle detecting device capable of being assembled to a slim portable device for gas monitoring. 
     BACKGROUND OF THE INVENTION 
     Suspended particles are solid particles or droplets contained in the air. Since the sizes of the suspended particles are really small, the suspended particles may enter the lungs of human body through the nasal hair in the nasal cavity easily, thus causing inflammation in the lungs, asthma or cardiovascular disease. If other pollutants are attached to the suspended particles, it will further increase the harm to the respiratory system. In recent years, the problem of air pollution is getting worse. In particular, the concentration of particle matters (e.g., PM2.5) is often too high. Therefore, the monitoring to the concentration of the gas suspended particles is taken seriously. However, the gas flows unstably due to variable wind direction and air volume, and the general gas-quality monitoring station is located in a fixed place. Under this circumstance, it is impossible for people to check the concentration of suspended particles in current environment. Thus, a miniature and portable gas detecting device is needed for allowing the user to check the concentration of surrounding suspended particles anytime and anywhere. 
     Therefore, there is a need of providing a particle detecting device for monitoring the concentration of suspended particles anytime and anywhere. 
     SUMMARY OF THE INVENTION 
     An object of the present disclosure provides a particle detecting device. A detecting channel and a beam channel are defined and partitioned in a slim base, and a laser transmitter and a particle sensor of the detecting element and the micro pump are positioned in the base. With the help of micro pump, the gas is transported along the detecting channel, which is a straight gas-flowing path. Thus, the introduced gas can pass through the orthogonal position of the detecting channel and the beam channel smooth and steady, and the size and concentration of the suspended particles contained in the gas can be detected. In addition, the light trapping structure of the light trapping region is a paraboloidal structure, and the light trapping distance between the beam channel and the position where the light trapping structure receives the projecting light source from the light transmitter is maintained to be greater than 3 mm. Accordingly, the projecting light source from the light transmitter forms a focus point on the paraboloidal light trapping structure, and the stray light being directly reflected back to the beam channel is reduced. Consequently, the particle detecting becomes more accurate. Moreover, there is a protective film, which covers on and seals the outer inlet terminal of the detecting channel. Consequently, the detecting channel is capable of introducing gas and being waterproof and dustproof at the same time, and the detection accuracy and lifespan of the detecting channel would not be affected. The particle detecting device of the present disclosure is really suitable to be assembled to the portable electric device and wearable accessory for forming a mobile particle detecting device allowing the user to monitor the concentration of surrounding suspended particles anytime and anywhere. 
     In accordance with an aspect of the present disclosure, a particle detecting device is provided. The particle detecting device includes a base and a detecting element. A detecting-element accommodation region, a micro-pump accommodation region, a detecting channel, a beam channel and a light trapping region are defined and partitioned inside the base. The detecting channel and the beam channel are perpendicular to each other. The beam channel perpendicularly passes through the detecting channel and communicates with the light trapping region. The detecting channel is a straight gas-flowing path. The micro-pump accommodation region is in fluid communication with the detecting channel. A light trapping structure is disposed in the light trapping region, and the light trapping structure is a paraboloidal structure and is disposed corresponding to the beam channel. The detecting element includes a microprocessor, a particle sensor and a laser transmitter. The laser transmitter is positioned in the detecting-element accommodation region and is configured to transmit a projecting light source to the light trapping region through the beam channel. The particle sensor is disposed at an orthogonal position where the detecting channel intersects the beam channel, thereby detecting a size and a concentration of suspended particles contained in a gas in the detecting channel. When the particle sensor and the laser transmitter are enabled under the control of the microprocessor, the laser transmitter transmits the projecting light source to the beam channel, and the particle sensor detects the size and the concentration of the suspended particles contained in the gas in the detecting channel. The projecting light source transmitted by the laser transmitter passes through the detecting channel, and the projecting light source is projected on the paraboloidal structure of the light trapping structure so that a stray light being directly reflected back to the beam channel is reduced. 
     The above contents of the present disclosure will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic exterior view illustrating a particle detecting device according to an embodiment of the present disclosure; 
         FIG. 2  is a schematic exploded view illustrating the components of the particle detecting device of the present disclosure; 
         FIG. 3  is a schematic perspective view illustrating a base of the particle detecting device of the present disclosure; 
         FIG. 4A  is a schematic perspective view illustrating the base of the particle detecting device and a micro pump of the present disclosure being assembled together; 
         FIG. 4B  schematically shows the gas flowing while the particle detecting device of the present disclosure is detecting; 
         FIG. 4C  schematically shows the gas flowing and the light source projecting while the particle detecting device of the present disclosure is detecting; 
         FIG. 5  is a schematic perspective view illustrating the micro pump of the particle detecting device of the present disclosure; 
         FIG. 6A  is a schematic exploded view illustrating the micro pump of the present disclosure and taken along front viewpoint; 
         FIG. 6B  is a schematic exploded view illustrating the micro pump of the present disclosure and taken along rear viewpoint; 
         FIG. 7A  is a schematic cross-sectional view illustrating the micro pump of the present disclosure; 
         FIG. 7B  is a schematic cross-sectional view illustrating a micro pump according to another embodiment of the present disclosure; 
         FIG. 8  is a partially enlarged view illustrating a conducting inside pin of the micro pump of the present disclosure; and 
         FIGS. 9A, 9B and 9C  schematically illustrate the actions of the micro pump of  FIG. 7A . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present disclosure will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed. 
     Please refer to  FIGS. 1 to 4C . The present disclosure provides a particle detecting device including a base  1 , a detecting element  2 , a micro pump  3 , a drive control board  4 , an outer cover  5  and a protective film  6 . The base  1  has a first surface  1   a  and a second surface  1   b , and the first surface  1   a  and the second surface  1   b  are two surfaces opposite to each other. A detecting-element accommodation region  11 , a micro-pump accommodation region  12 , a detecting channel  13 , a beam channel  14  and a light trapping region  15  are defined and partitioned inside the base  1 . The detecting channel  13  and the beam channel  14  are perpendicular to each other. The beam channel  14  perpendicularly penetrates through the detecting channel  13  and is in fluid communication with the light trapping region  15 . More specifically, the detecting channel  13  extends along a first direction and the beam channel  14  extends along a second direction, and the first direction is perpendicular to the second direction. The detecting channel  13  extends straight from one side of the beam channel  14  to the other side of the beam channel  14 , and thus the detecting channel  13  intersects the beam channel  14 . The drive control board  4  is covered on the second surface  1   b  of the base  1 , and the detecting channel  13  is covered by the drive control board  4  to form a straight gas-flowing path. The protective film  6  covers on and seals the outer inlet terminal of the detecting channel  13 . The protective film  6  is a film structure, which is waterproof and dustproof but allows the gas to penetrate therethrough. Consequently, the detecting channel  13  is capable of introducing gas while being waterproof and dustproof, by which the larger particles contained in the outside air are filtered out. In this way, the protective film  6  may avoid introducing the larger particles into the detecting channel  13 , and the detecting channel  13  is free of pollution. In other words, only the smaller suspended particles (e.g., PM2.5) are introduced into the detecting channel  13  for detection, and the detection accuracy and lifespan of the detecting channel  13  would not be affected. The detecting element  2  is packaged and positioned on the drive control board  4 , and the detecting element  2  is electrically connected to the drive control board  4 . The detecting element  2  is disposed in the detecting-element accommodation region  11 . The micro pump  3  is electrically connected to the drive control board  4 , and the operation of the micro pump  3  is driven and controlled by the drive control board  4 . An accommodation frame slot  121  and an inlet  122  are disposed at the bottom of the micro-pump accommodation region  12 , and an outlet  123  in fluid communication with the outside space is disposed at the top of the micro-pump accommodation region  12 . The inlet  122  is in fluid communication between the detecting channel  13  and the accommodation frame slot  121 . The micro pump  3  is accommodated and positioned on the accommodation frame slot  121 . When the micro pump  3  is enabled, a suction force is generated in the detecting channel  13  in fluid communication with the accommodation frame slot  121 , and the gas outside the detecting channel  13  is inhaled into the detecting channel  13  by the suction force. Afterwards, by the transportation of the micro pump  3 , the gas is introduced to the space above the accommodation frame slot  121 , and then the gas is discharged from the outlet  123  into the space outside the particle detecting device. Consequently, the gas transportation for gas detection is realized, and the gas is transported along the path indicated by the arrows shown in  FIG. 4B . In addition, a light trapping structure  151  is disposed in the light trapping region  15  and is corresponding to the beam channel  14 . The light trapping structure  151  is a paraboloidal structure utilized for making the projecting light source L from the beam channel  14  form a focus point thereon, so as to reduce the stray light. Moreover, as shown in  FIG. 4C , a light trapping distance W is maintained between the beam channel  14  and the position where the light trapping structure  151  receives the projecting light source L. More specifically, the beam channel  14  has two openings, one is an entry opening and the other is an exit opening. The entry opening allows the light to enter the beam channel  14 , and the exit opening allows the light to leave the beam channel  14  and toward the light trapping structure  151 . The light trapping distance W is the distance between the exit opening of the beam channel  14  and the focus point on the light trapping structure  151 . It is noted that the light trapping distance W has to be greater than 3 mm. If the light trapping distance W is smaller than 3 mm, much of the stray light would be directly reflected back to the beam channel  14  when the projecting light source L projected on and is reflected by the light trapping structure  151 . Under this circumstance, the detection accuracy may be influenced and distorted (i.e., lack fidelity). Conventionally, the light trapping structure has an inclination of 45 degrees, and the light trapping distance is not taken into consideration, which may cause too much stray light being directly reflected back to the beam channel and further affect the detection accuracy. Different from the conventional technique, in the present disclosure, the light trapping structure  151  is a paraboloidal structure, and the light trapping distance W is greater than 3 mm, which can overcome the said drawbacks of the conventional technique. 
     Please refer to  FIGS. 4A, 4B and 4C . The detecting element  2  includes a microprocessor  21 , a particle sensor  22  and a laser transmitter  23 . The microprocessor  21 , the particle sensor  22  and the laser transmitter  23  are packaged on the drive control board  4 . The laser transmitter  23  is disposed in the detecting-element accommodation region  11 , and the laser transmitter  23  is configured to transmit the projecting light source L to the beam channel  14 . As described above, the detecting channel  13  is perpendicular to the beam channel  14 , and thus there is the orthogonal position located at the intersection of the detecting channel  13  and the beam channel  14 . The particle sensor  22  is disposed at the orthogonal position where the detecting channel  13  intersects the beam channel  14 . The laser transmitter  23  and the particle sensor  22  are driven and controlled by the microprocessor  21 . The projecting light source L from the laser transmitter  23  is controlled to be projected into the beam channel  14  and pass through the orthogonal position where the detecting channel  13  intersects the beam channel  14 . Thereby, the suspended particles (e.g., PM2.5) contained in the passing gas in the detecting channel  13  is irradiated by the projecting light source L, and the projection light points generated accordingly are projected on the particle sensor  22  for detection and calculation. The particle sensor  22  detects the size and concentration of the suspended particles contained in the gas and outputs a detection signal. The microprocessor  21  receives and analyzes the detection signal outputted by the particle sensor  22 , and the microprocessor  21  outputs a detection data. The particle sensor  22  is a PM2.5 sensor. 
     Please refer to  FIGS. 1 and 2  again. The outer cover  5  includes a top cover  5   a  and a bottom cover  5   b . The top cover  5  is covered on the first surface  1   a  of the base  1 . The top cover  5  has an inlet hole  51   a  and an outlet hole  52   a . The inlet hole  51   a  is disposed corresponding in position to the outer inlet terminal of the detecting channel  13  of the base  1 . The outlet hole  52   a  is disposed corresponding in position to the outlet  123  of the micro-pump accommodation region  12 . The bottom cover  5   b  is covered on the second surface  1   b  of the base  1 , and the bottom cover  5   b  and top cover  5   a  are engaged with each other to seal the base  1 . The bottom cover  5   b  has an inlet opening  51   b  and an outlet opening  52   b . The inlet opening  51   b  is disposed corresponding in position to the inlet hole  51   a  of the top cover  5   a . The outlet opening  52   b  is disposed corresponding in position to the outlet hole  52   a  of the top cover  5   a . Therefore, the gas outside the particle detecting device can be introduced into the detecting channel  13  of the base  1  through the inlet opening  51   b  and the inlet hole  51   a . The gas in the detecting channel  13  of the base  1  is released from the outlet  123  of the micro-pump accommodation region  12  and is further discharged to the space outside the particle detecting device through the outlet hole  52   a  and the outlet opening  52   b.    
     Please refer to  FIGS. 2, 4A, 4B, 4C, 5, 6A, 6B and 7A . The micro pump  3  is accommodated in the accommodation frame slot  121  of the micro-pump accommodation region  12  of the base  1 . The micro pump  3  includes a gas inlet plate  31 , a resonance plate  32 , a piezoelectric actuator  33 , an insulation plate  34  and a conducting plate  35 , which are stacked on each other sequentially. The gas inlet plate  31  has at least one inlet aperture  31   a , at least one convergence channel  31   b  and a convergence chamber  31   c . The number of the inlet aperture  31   a  is the same as the number of the convergence channel  31   b . In this embodiment, the number of the inlet aperture  31   a  and the convergence channel  31   b  is exemplified by four for each but not limited thereto. The four inlet apertures  31   a  penetrate through the four convergence channels  31   b  respectively, and the four convergence channels  31   b  converge to the convergence chamber  31   c.    
     The resonance plate  32  is assembled on the gas inlet plate  31  by attaching. The resonance plate  32  has a central aperture  32   a , a movable part  32   b  and a fixed part  32   c . The central aperture  32   a  is located in the center of the resonance plate  32  and is aligned with the convergence chamber  31   c  of the gas inlet plate  31 . The region of the resonance plate  32  around the central aperture  32   a  and corresponding to the convergence chamber  31   c  is the movable part  32   b . The region of the periphery of the resonance plate  32  securely attached on the gas inlet plate  31  is the fixed part  32   c.    
     The piezoelectric actuator  33  includes a suspension plate  33   a , an outer frame  33   b , at least one connecting part  33   c , a piezoelectric element  33   d , at least one vacant space  33   e  and a bulge  33   f . The suspension plate  33   a  is a square suspension plate having a first surface  331   a  and a second surface  332   a  opposite to the first surface  331   a . The outer frame  33   b  is disposed around the periphery of the suspension plate  33   a . The outer frame  33   b  has an assembling surface  331   b  and a bottom surface  332   b . The at least one connecting part  33   c  is connected between the suspension plate  33   a  and the outer frame  33   b  for elastically supporting the suspension plate  33   a . The first surface  331   a  of the suspension plate  33   a  is coplanar with the assembling surface  331   b  of the outer frame  33   b . The second surface  332   a  of the suspension plate  33   a  is coplanar with the bottom surface  332   b  of the outer frame  33   b . The at least one vacant space  33   e  is formed among the suspension plate  33   a , the outer frame  33   b  and the at least one connecting part  33   c  for allowing the gas to flow through. 
     In addition, the first surface  331   a  of the suspension plate  33   a  has the bulge  33   f . In this embodiment, the formation of the bulge  33   f  may be made by using an etching process, in which the region between the periphery of the bulge  33   f  and the junction of the suspension plate  33   a  and the least one connecting part  33   c  is partially removed to be concaved. Accordingly, the bulge surface  331   f  of the bulge  33   f  of the suspension plate  33   a  is higher than the first surface  331   a , and a stepped structure is formed. Additionally, the outer frame  33   b  is disposed around the outside of the suspension plate  33   a , and the outer frame  33   b  has a conducting pin  333   b  extended outwardly. Preferably but not exclusively, the conducting pin  333   b  is configured for electrical connection. 
     The resonance plate  32  and the piezoelectric actuator  33  are stacked and assembled to each other via a filling material g, and a chamber space  36  is formed between the resonance plate  32  and the piezoelectric actuator  33 . The filling material g is for example but not limited to a conductive adhesive. The filling material g is configured to form a gap h between the resonance plate  32  and the piezoelectric actuator  33 . Namely, a depth of the gap h is maintained between resonance plate  32  and the bulge surface  331   f  of the bulge  33   f  on the suspension plate  33   a  of the piezoelectric actuator  33 . Therefore, the transported gas can flow faster. Further, due to the proper distance maintained between the bulge  33   f  of the suspension plate  33   a  and the resonance plate  32 , the contact and interference therebetween are reduced, which also reduces the noise generated. 
     In another embodiment, as shown in  FIG. 7B , the resonance plate  32  and the piezoelectric actuator  33  are stacked and assembled to each other via a filling material g, and a chamber space  36  is formed between the resonance plate  32  and the piezoelectric actuator  33 . In addition, the suspension plate  33   a  is further processed by using a stamping method, by which the outer frame  33   b , the connecting part  33   c  and the suspension plate  33   a  have a concave profile in cross section for forming the chamber space  36 . The concave distance can be adjusted through changing an inclined angle of the at least one connecting part  33   c  formed between the suspension plate  33   a  and the outer frame  33   b . Consequently, the first surface  331   a  of the suspension plate  33   a  is not coplanar with the assembling surface  331   b  of the outer frame  33   b . Namely, the first surface  331   a  of the suspension plate  33   a  is lower than the assembling surface  331   b  of the outer frame  33   b , and the second surface  332   a  of the suspension plate  33   a  is lower than the bottom surface  332   b  of the outer frame  33   b . Moreover, the bulge surface  331   f  of the bulge  33   f  on the suspension plate  33   a  is selective to be lower than the assembling surface  331   b  of the outer frame  33   b . In the embodiment, the piezoelectric element  33   d  is attached on the second surface  332   a  of the suspension plate  33   a  and is disposed opposite to the bulge  33   f . In response to an applied driving voltage, the piezoelectric element  33   d  is subjected to a deformation owing to the piezoelectric effect so as to drive the suspension plate  33   a  to bend and vibrate. In an embodiment, a small amount of filling material g is applied to the assembling surface  331   b  of the outer frame  33   b , and the piezoelectric actuator  33  is attached on the fixed part  32   c  of the resonance plate  32  after a hot pressing process. Therefore, the piezoelectric actuator  33  and the resonance plate  32  are assembled together. 
     Since the gap h formed between the first surface  331   a  of the suspension plate  33   a  and the resonance plate  32  influences the transportation effect of the micro pump  3 , it is important to maintain the gap g at a fixed depth for the micro pump  3  in providing stable transportation efficiency. The suspension plate  33   a  of the micro pump  3  is processed by the stamping method to be concaved in a direction away from the resonance plate  32 . Consequently, the first surface  331   a  of the suspension plate  33   a  is not coplanar with the assembling surface  331   b  of the outer frame  33   b . Namely, the first surface  331   a  of the suspension plate  33   a  is lower than the assembling surface  331   b  of the outer frame  33   b , and the second surface  332   a  of the suspension plate  33   a  is lower than the bottom surface  332   b  of the outer frame  33   b . As a result, a space is formed between the concaved suspension plate  33   a  of the piezoelectric actuator  33  and the resonance plate  32 , and the space has an adjustable gap h. The present disclosure provides an improved structure in which the suspension plate  33   a  of the piezoelectric actuator  33  is processed by the stamping method to be concaved for forming the gap h. Therefore, the required gap h can be formed by adjusting the concaved distance of the suspension plate  33   a  of the piezoelectric actuator  33 , which simplifies the structural design regarding the adjustment of the gap h and achieves the advantages of simplifying the process and shortening the processing time. 
     Please refer to  FIGS. 6A and 8 . The insulation plate  34  and the conducting plate  35  are both thin frame-shaped plates, which are stacked sequentially on the piezoelectric actuator  33 . In this embodiment, the insulation plate  34  is attached on the bottom surface  332   b  of the outer frame  33   b  of the piezoelectric actuator  33 . The conducting plate  35  is stacked on the insulation plate  34 , and the shape of the conducting plate  35  is corresponding to the shape of the outer frame  33   b  of the piezoelectric actuator  33 . In an embodiment, the insulation plate  34  is formed by insulated material for insulation, for example but not limited to plastic. In an embodiment, the conducting plate  35  is formed by conductive material for electrical conduction, for example but not limited to metal. In an embodiment, a conducting pin  351   a  is disposed on the conducting plate  35  for electrical conduction. With regard to the two driving electrodes of the piezoelectric element  33   d  of the piezoelectric actuator  33 , the conventional way is to fix a conducting wire on the piezoelectric element  33   d  by soldering, so as to extend out the electrode for electrical connection. However, it requires jigs to fix the conducting wire while extending out the electrode of the piezoelectric element  33   d , and the fixed position of the conducting wire has to be varied according to different working procedures, which greatly increases the complicated level of assembling. In order to overcome the drawbacks caused by the conventional way of utilizing the conducting wire to extend out the electrode for electrical connection, the present disclosure utilizes the conducting plate  35  to provide a conducting inside pin  351   b  as one electrode of the two driving electrodes of the piezoelectric element  33   d . The conducting inside pin  351   b  is formed from processing the conducting plate  35  by a stamping method. The conducting plate  35  may be a frame structure. The conducting inside pin  351   b  may be any shape extending inwardly from any side of the frame of the conducting plate  35 , and the conducting inside pin  351   b  defines a conducting position configured to allow the external element to electrically connect the electrode. The conducting inside pin  351   b  is extended inwardly from any side of the frame of the conducting plate  35  to form an extension part  3511   b  with a bending angle θ and a bending height H, and the extension part  3511   b  has a bifurcation part  3512   b . The bending height H is maintained between the bifurcation part  3512   b  and the frame of the conducting plate  35 . The most appropriate height of the bending height H is equal to the thickness of the piezoelectric element  33   d  for allowing the bifurcation part  3512   b  to attach on the surface of the piezoelectric element  33   d , which achieves the best effect of the contact between the bifurcation part  3512   b  and the piezoelectric element  33   d . In this embodiment, there is an interval P in the middle of the bifurcation part  3512   b , as shown in  FIG. 5 . The bifurcation part  3512   b  may be securely connected to the surface of the piezoelectric element  33   d  via the mediums applied to the interval P. These mediums may be, for example, melted alloy, conductive adhesive, conductive ink, conductive resin or combinations thereof. With the fork-like design of the bifurcation part  3512   b , better adhesion effect can be achieved when applied with the mediums as described above. 
       FIGS. 9A, 9B and 9C  schematically illustrate the actions of the micro pump  3  of  FIG. 7A . Please refer to  FIG. 9A . When a driving voltage is applied to the piezoelectric element  33   d  of the piezoelectric actuator  33 , the piezoelectric element  33   d  deforms to drive the suspension plate  33   a  to move in the direction away from the gas inlet plate  31 . At the same time, the resonance plate  32  is in resonance with the piezoelectric actuator  33  to move in the direction away from the gas inlet plate  31 . Accordingly, the volume of the chamber space  36  is increased, and a negative pressure is formed in the chamber space  36 . The gas outside the micro pump  3  is inhaled through the inlet aperture  31   a , then flows into the convergence chamber  31   c  through the convergence channel  31   b , and finally flows into the chamber space  36  through the central aperture  32   a . Please refer to  FIG. 9B . The piezoelectric element  33   d  drives the suspension plate  33   a  to move toward the gas inlet plate  31 , and the volume of the chamber space  36  is compressed, so that the gas in the chamber space  36  is forced to flow through the vacant space  33   e  in the direction away from the gas inlet plate  31 . Thereby, the air transportation efficacy is achieved. Meanwhile, the resonance plate  32  is moved toward the gas inlet plate  31  in resonance with the suspension plate  33   a , and the gas in the convergence chamber  31   c  is pushed to move toward the chamber space  36  synchronously. Moreover, the movable part  32   b  of the resonance plate  32  is moved toward the gas inlet plate  31 , and the gas is stopped being inhaled through the inlet aperture  31   a . Please refer to  FIG. 9C . When the suspension plate  33   a  is driven to move in the direction away from the gas inlet plate  31  for returning to the horizontal position that the piezoelectric actuator  33  does not operate, the movable part  32   b  of the resonance plate  32  is moved in the direction away from the gas inlet plate  31  in resonance with the suspension plate  33   a . Meanwhile, the gas in the chamber space  36  is compressed by the resonance plate  32  and is transferred toward the vacant space  33   e . The volume of the convergence chamber  31   c  is expanded, and the air is allowed to flow through the inlet aperture  31   a  and the convergence channel  31   b  and converge in the convergence chamber  31   c  continuously. By repeating the above actions shown in  FIGS. 9A to 9C , the air is continuously introduced through the inlet aperture  31   a  into the micro pump  3 , and then the air is transferred through the vacant space  33   e  in the direction away from the gas inlet plate  31 . Consequently, the gas is continuously inhaled into the micro pump  3 , and the operation of transferring the gas in the micro pump  3  is realized. 
     As described above, the present disclosure provides a particle detecting device. The micro pump  3  is disposed in the accommodation frame slot  121  of the micro-pump accommodation region  12  of the base  1 , and the inlet aperture  31   a  of the gas inlet plate  31  is sealed in the accommodation frame slot  121  and is in fluid communication with the inlet  122 . When the micro pump  3 , the particle sensor  22  and the laser transmitter  23  are enabled under the control of the microprocessor  21 , the suction force is generated in the detecting channel  13  in fluid communication with the accommodation frame slot  121  by the operation of the micro pump  3 . The suction force allows the gas outside the detecting channel  13  to be inhaled into the detecting channel  13 . Since the detecting channel  13  is a straight gas-flowing path, the inhaled gas flows in the detecting channel  13  smooth and steady. Moreover, the gas in the detecting channel  13  passes through the orthogonal position where the detecting channel  13  intersects the beam channel  14 . The passing gas is irradiated by the projecting light source L from the laser transmitter  23 , which causes the projection light points being projected on the particle sensor  22 . Thereby, the particle sensor  22  can detect the size and concentration of the suspended particles contained in the gas. In addition, the projecting light source L along the beam channel  14  passes through the detecting channel  13  and is projected on the light trapping structure  151  of the light trapping region  15 . Accordingly, a focus point is formed on the paraboloidal structure of the light trapping structure  151  so that the stray light is reduced. Further, a light trapping distance W is maintained between the beam channel  14  and the position where the light trapping structure  151  receives the projecting light source L, and the light trapping distance W is greater than 3 mm. Therefore, the stray light being directly reflected back to the beam channel  14  is reduced, the detection accuracy would not be distorted, and the particle detecting becomes more accurate. Moreover, the protective film  6  covers on and seals the outer inlet terminal of the detecting channel  13 . Therefore, the detecting channel  13  is capable of introducing gas while being waterproof and dustproof, by which the larger particles contained in the outside air are filtered out. In this way the protective film  6  may avoid introducing the larger particles into the detecting channel  13 , and the detecting channel  13  is free of pollution. In other words, only the smaller suspended particles (e.g., PM2.5) are introduced into the detecting channel  13  for detection, and the detection accuracy and lifespan of the detecting channel  13  would not be affected. The particle detecting device provided in the present disclosure may be assembled to the portable electric device for forming a mobile particle detecting device. The portable electric device is for example but not limited to a mobile phone, a tablet computer, a wearable device or a notebook computer. Alternatively, the particle detecting device provided in the present disclosure may be assembled to the wearable accessory for forming a mobile particle detecting device. The wearable accessory is for example but not limited to a charm, a button, a glasses or a wrist watch. 
     From the above descriptions, the present disclosure provides a particle detecting device. A detecting channel and a beam channel are defined and partitioned in a slim base, and a laser transmitter and a particle sensor of the detecting element and the micro pump are positioned in the base. With the help of micro pump, the gas is transported along the detecting channel, which is a straight gas-flowing path. Thus, the introduced gas can pass through the orthogonal position where the detecting channel intersects the beam channel smoothly and steadily, and the size and concentration of the suspended particles contained in the gas can be detected. In addition, the light trapping structure of the light trapping region is a paraboloidal structure, and the light trapping distance between the beam channel and the position where the light trapping structure receives the projecting light source from the light transmitter is maintained to be greater than 3 mm. Accordingly, the projecting light source from the light transmitter forms a focus point on the paraboloidal light trapping structure, and the stray light being directly reflected back to the beam channel is reduced. Consequently, the particle detecting becomes more accurate. Moreover, there is a protective film, which covers on and seals the outer inlet terminal of the detecting channel. Consequently, the detecting channel is capable of introducing gas and being waterproof and dustproof at the same time, and the detection accuracy and lifespan of the detecting channel would not be affected. The particle detecting device of the present disclosure is really suitable to be assembled to the portable electric device and wearable accessory for forming a mobile particle detecting device allowing the user to monitor the concentration of surrounding suspended particles anytime and anywhere. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.