Pyroelectric infrared sensor with low heat loss

Abstract

The utility model belongs to the technical field of sensors, and particularly relates to a low-heat-loss pyroelectric infrared sensor, which comprises a packaging base, a circuit board is arranged on the top surface of the packaging base, an assembly structure is arranged on the top surface of the circuit board, the assembly structure comprises symmetrically arranged fixing rods, and the fixing rods are arranged on the top surface of the circuit board. The fixed rods are fixedly connected to the top surface of the circuit board; the fixing rod and the supporting frame can be used in cooperation, a certain distance exists between the thermosensitive unit and the circuit board after the thermosensitive unit is assembled, the thermosensitive unit does not make direct contact with the circuit board, the thermosensitive unit only makes contact with the multiple connecting columns and conducts heat, the physical contact area between the thermosensitive unit and the supporting structure is reduced, and the service life of the thermosensitive unit is prolonged. The heat conduction of the heat-sensitive unit radiating heat to the outside through a solid path is greatly reduced, the heat loss is reduced, the assembly structure is simple, and compared with the MEMS micro-bridge technology, the assembly of the heat-sensitive unit is more convenient.

Description

Technical Field

[0001] This utility model belongs to the field of sensor technology, specifically relating to a pyroelectric infrared sensor with low heat loss. Background Technology

[0002] A pyroelectric infrared sensor is a sensor that detects changes in infrared radiation using the pyroelectric effect. It can sense changes in infrared radiation caused by changes in the temperature of an object and is widely used in fields such as human body sensing, intrusion alarms, and automatic lighting control. The core principle of a pyroelectric infrared sensor is the pyroelectric effect. When the temperature change of the infrared radiation emitted by an object affects the sensor surface, the charge on the sensor material changes. Pyroelectric materials have the characteristic of generating charges when the temperature changes. The sensor detects temperature fluctuations by measuring these changes in charge. Heat loss is one of the main limiting factors for the performance of pyroelectric infrared sensors, including the effects of heat conduction and heat radiation. Current technologies typically use MEMS microbridge technology to reduce the contact between the thermistor and the circuit board; however, this involves complex MEMS fabrication technology, leading to greater assembly difficulty and higher cost for the sensor.

[0003] To address the aforementioned issues, this application proposes a pyroelectric infrared sensor with low heat loss. Utility Model Content

[0004] To address the problems mentioned in the background section, this invention provides a pyroelectric infrared sensor with low heat loss, characterized by its ability to reduce heat loss.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a pyroelectric infrared sensor with low heat loss, comprising an encapsulation base, a circuit board disposed on the top surface of the encapsulation base, and an assembly structure disposed on the top surface of the circuit board;

[0006] The assembly structure includes symmetrically arranged fixing rods, each fixedly connected to the top surface of the circuit board. A support frame is fixedly connected to the top of each fixing rod. The support frames on both sides are symmetrically arranged. A support plate is fixedly connected to each support frame. Connecting posts are fixedly connected to both ends of each support plate. A support ring is fixedly connected to the outer wall of each connecting post. A thermal unit is provided on the top of the circuit board. A connecting plate is fixedly connected to each thermal unit near each connecting post. A third connecting hole is provided on each connecting plate. The connecting plates are respectively disposed on the top surface of the nearest supporting ring, and the connecting post is fixedly connected to the nearest third connecting hole.

[0007] As a preferred embodiment of the low-heat-loss pyroelectric infrared sensor of this utility model, the bottom of the thermistor unit is provided with a connection pin, the bottom end of the connection pin is soldered to the top surface of the circuit board, each of the fixing rods is made of insulating material, and each of the support frames is a Z-shaped structure.

[0008] As a preferred embodiment of the low-heat-loss pyroelectric infrared sensor of this utility model, each of the fixed rods has a threaded hole at its top, each of the support frames has a mounting hole at its top, and each of the support frames has a hidden groove at its top near the mounting hole. Each mounting hole contains a connecting bolt, and the support frame is fixedly connected to the fixed rod by using the connecting bolts passing through the mounting hole and the threaded hole. The tops of the connecting bolts are respectively located in the hidden grooves near each other.

[0009] As a preferred embodiment of the low-heat-loss pyroelectric infrared sensor of this invention, the circuit board is provided with an encapsulation shell on its outer side, and the encapsulation shell is fixedly connected to the top surface of the encapsulation base.

[0010] As a preferred embodiment of the low-heat-loss pyroelectric infrared sensor of this utility model, a packaging cover is fixedly connected to the top surface of the packaging shell, and a filter is provided at the center of the packaging cover.

[0011] As a preferred embodiment of the low-heat-loss pyroelectric infrared sensor of this utility model, the packaging base is provided with a plurality of first connection holes, and the circuit board is provided with a second connection hole near each of the first connection holes. Each of the first connection holes is provided with a main pin, and the top end of the main pin passes through the adjacent second connection hole and is soldered to the top surface of the circuit board.

[0012] As a preferred embodiment of the low-heat-loss pyroelectric infrared sensor of this utility model, a heat insulation plate is provided between the circuit board and the packaging base, and a fourth connection hole is provided on the heat insulation plate near each of the first connection holes, and the main pins pass through the adjacent fourth connection holes respectively.

[0013] As a preferred embodiment of the pyroelectric infrared sensor with low heat loss according to this utility model, a heat insulation layer is fixedly connected to the inner wall of the encapsulation shell.

[0014] As a preferred embodiment of the pyroelectric infrared sensor with low heat loss according to this utility model, both the heat insulation layer and the heat insulation plate are provided with insulating material.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows: An assembly structure is added to this application, which utilizes the cooperation of a fixing rod and a support frame. After assembly, the thermal unit maintains a certain distance from the circuit board, and the thermal unit does not directly contact the circuit board. The thermal unit only contacts and conducts heat with multiple connecting posts, reducing the physical contact area between the thermal unit and the support structure. This significantly reduces heat conduction from the thermal unit to the outside through solid paths, lowering heat loss. Furthermore, the assembly structure is simple and more convenient for assembling the thermal unit compared to MEMS microbridge technology. Simultaneously, a heat insulation layer and heat insulation plate are added. By setting the heat insulation plate and heat insulation layer with insulating material, heat can be blocked from inside the sensor, reducing the thermal radiation from the thermal unit to the sensor package, thereby reducing heat loss to the environment through the package and further reducing the sensor's heat loss. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 This is a structural schematic diagram showing the location of the thermal unit in this utility model;

[0019] Figure 3 This is a structural schematic diagram of the position of the fixing rod in this utility model;

[0020] Figure 4 This is a structural schematic diagram of the support frame position in this utility model;

[0021] Figure 5 This is a structural diagram showing the location of the circuit board in this utility model;

[0022] Figure 6 This is a structural diagram showing the location of the heat insulation pad in this utility model;

[0023] In the picture:

[0024] 1. Encapsulation base; 11. First connection hole; 2. Main pin; 3. Circuit board; 31. Second connection hole; 4. Assembly structure; 41. Fixing rod; 42. Threaded hole; 43. Support frame; 44. Mounting hole; 45. Hidden groove; 46. Connecting bolt; 47. Support plate; 48. Connecting post; 49. Support ring; 410. Connecting plate; 411. Third connection hole; 5. Thermistor unit; 51. Connecting pin; 6. Encapsulation shell; 7. Heat insulation layer; 8. Encapsulation cover; 81. Filter; 9. Heat insulation plate; 91. Fourth connection hole. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] Example 1

[0027] like Figures 1 to 4 As shown;

[0028] To reduce heat loss, this low-heat-loss pyroelectric infrared sensor includes a package base 1, a circuit board 3 is disposed on the top surface of the package base 1, and an assembly structure 4 is disposed on the top surface of the circuit board 3.

[0029] The assembly structure 4 includes symmetrically arranged fixing rods 41, each of which is fixedly connected to the top surface of the circuit board 3. Each fixing rod 41 has a support frame 43 fixedly connected to its top end. The support frames 43 on both sides are symmetrically arranged. Each support frame 43 has a support plate 47 fixedly connected to its top end. Each support plate 47 has a connecting post 48 fixedly connected to its ends. Each connecting post 48 has a support ring 49 fixedly connected to its outer wall. A thermal unit 5 is provided on the top of the circuit board 3. A connecting plate 410 is fixedly connected to the thermal unit 5 near each connecting post 48. Each connecting plate 410 has a third connecting hole 411. The connecting plates 410 are respectively located on the top surface of the nearby support ring 49. The connecting post 48 is fixedly connected in the nearby third connecting hole 411.

[0030] In this implementation scheme: When assembling the thermal unit 5, the connecting plates 410 on both sides of the thermal unit 5 are placed on the nearby support ring 49, and the connecting posts 48 are inserted into the third connecting holes 411 on the nearby connecting plate 410. Then, the connecting plates 410 are fixed to the support ring 49 by soldering, thus completing the assembly of the thermal unit 5. Since there is a certain distance between the thermal unit 5 and the circuit board 3 after assembly, and the thermal unit 5 does not directly contact the circuit board 3, the thermal unit 5 only contacts and conducts heat with multiple connecting posts 48, which reduces the physical contact area between the thermal unit 5 and the support structure. This significantly reduces the heat conduction of the thermal unit 5 to the outside through the solid path, reducing heat loss. Moreover, the assembly structure 4 has a simple structure, which is more convenient for assembling the thermal unit 5 compared to MEMS microbridge technology.

[0031] Furthermore:

[0032] like Figure 3 and Figure 4 As shown;

[0033] Based on the above:

[0034] To reduce the size of the sensor, in an optional embodiment, the bottom of the thermal unit 5 is provided with a connection pin 51, the bottom end of the connection pin 51 is soldered to the top surface of the circuit board 3, each fixing rod 41 is made of insulating material, and each support frame 43 is a Z-shaped structure.

[0035] In this embodiment, the thermal unit 5 is electrically connected to the circuit board 3 via the connection pin 51. The Z-shaped support frame 43 can prevent the thermal unit 5 from protruding too much without contacting the circuit board 3, thereby facilitating the assembly of the sensor and preventing the sensor from becoming too large.

[0036] Furthermore:

[0037] like Figures 2 to 4 As shown;

[0038] Based on the above:

[0039] To facilitate the installation of the support frame 43, in an optional embodiment, each fixing rod 41 has a threaded hole 42 at its top, each support frame 43 has a mounting hole 44 at its top, and each support frame 43 has a hidden groove 45 near the mounting hole 44 at its top. Each mounting hole 44 is provided with a connecting bolt 46. The support frame 43 is fixedly connected to the fixing rod 41 by using the connecting bolt 46 passing through the mounting hole 44 and the threaded hole 42. The top of the connecting bolt 46 is respectively located in the nearby hidden groove 45.

[0040] In this embodiment: When assembling the sensor, the thermal unit 5 can be assembled on the support frame 43 first, and then the support frame 43 can be installed. The top of the support frame 43 is placed on the fixing rod 41, and the support frame 43 is fixed with the connecting bolt 46. Then, the connecting pin 51 on the thermal unit 5 is soldered to the circuit board 3 using soldering technology, which facilitates the assembly of the thermal unit 5. Furthermore, the top of the connecting bolt 46 can be hidden by setting the hidden groove 45 to prevent the connecting bolt 46 from protruding.

[0041] Furthermore:

[0042] like Figures 1 to 3 As shown;

[0043] Based on the above:

[0044] In order to protect the thermal unit 5, in an optional embodiment, a package shell 6 is provided on the outside of the circuit board 3. The package shell 6 is fixedly connected to the top surface of the package base 1. A package cover 8 is fixedly connected to the top surface of the package shell 6. A filter 81 is provided at the center of the package cover 8.

[0045] In this embodiment: after the thermal unit 5 is assembled, the encapsulation shell 6 can be fixed on the encapsulation base 1, and the encapsulation cover 8 can be fixed on the top of the encapsulation shell 6 to complete the encapsulation assembly of the sensor.

[0046] Furthermore:

[0047] like Figures 1 to 4 As shown;

[0048] Based on the above:

[0049] In order to connect the circuit board 3, in an optional embodiment, the packaging base 1 is provided with a plurality of first connection holes 11, and the circuit board 3 is provided with a second connection hole 31 near each of the first connection holes 11. Each first connection hole 11 is provided with a main pin 2, and the top end of the main pin 2 passes through the nearby second connection hole 31 and is soldered to the top surface of the circuit board 3.

[0050] Furthermore:

[0051] like Figures 2 to 5 As shown;

[0052] Based on the above:

[0053] To reduce heat loss to the environment through the package, in an optional embodiment, a heat insulation plate 9 is provided between the circuit board 3 and the package base 1. The heat insulation plate 9 has a fourth connection hole 91 near each of the first connection holes 11. The main pins 2 pass through the adjacent fourth connection holes 91 respectively. A heat insulation layer 7 is fixedly connected to the inner wall of the package shell 6. Both the heat insulation layer 7 and the heat insulation plate 9 are provided with insulating material.

[0054] In this embodiment: by setting the heat insulation plate 9 and the heat insulation layer 7 made of insulating material, heat can be blocked from the inside of the sensor, reducing the heat radiation of the thermal unit 5 to the sensor package, thereby reducing the heat loss to the environment through the package, and further reducing the heat loss of the sensor.

[0055] The working principle and usage process of this utility model are as follows: When assembling the sensor, the thermal unit 5 can be first assembled on the support frame 43. The connecting plates 410 on both sides of the thermal unit 5 are placed on the adjacent support ring 49, and the connecting posts 48 are inserted into the third connecting holes 411 on the adjacent connecting plates 410. Then, the connecting plates 410 are fixed to the support ring 49 using soldering, thus completing the assembly of the thermal unit 5. Since there is a certain distance between the thermal unit 5 and the circuit board 3 after assembly, and the thermal unit 5 does not directly contact the circuit board 3, the thermal unit 5 only contacts and conducts heat with multiple connecting posts 48. This reduces the physical contact area between the thermal unit 5 and the support structure, significantly reduces the heat conduction of the thermal unit 5 to the outside through the solid path, reduces heat loss, and the assembly structure 4... With a simple structure, the thermal unit 5 is easier to assemble compared to MEMS microbridge technology. Next, the support frame 43 is installed, with its top placed on the fixing rod 41 and secured with connecting bolts 46. Then, the connecting pins 51 on the thermal unit 5 are soldered to the circuit board 3 using soldering technology, facilitating the assembly of the thermal unit 5. After assembling the thermal unit 5, the encapsulation shell 6 is fixed to the encapsulation base 1, and the encapsulation cover 8 is fixed to the top of the encapsulation shell 6, completing the sensor encapsulation assembly. Furthermore, by setting up an insulating heat insulation plate 9 and a heat insulation layer 7, heat can be blocked from the inside of the sensor, reducing the thermal radiation from the thermal unit 5 to the sensor encapsulation, thereby reducing heat loss to the environment through the encapsulation and further reducing the sensor's heat loss.

[0056] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A pyroelectric infrared sensor with low heat loss, comprising a packaging base (1), characterized in that: A circuit board (3) is provided on the top surface of the packaging base (1), and an assembly structure (4) is provided on the top surface of the circuit board (3); The assembly structure (4) includes symmetrically arranged fixing rods (41), each fixing rod (41) is fixedly connected to the top surface of the circuit board (3), and a support frame (43) is fixedly connected to the top of each fixing rod (41). The support frames (43) on both sides are symmetrically arranged. A support plate (47) is fixedly connected to each support frame (43). A connecting post (48) is fixedly connected to both ends of each support plate (47). A support ring (49) is fixedly connected to the outer wall of each connecting post (48). A thermal unit (5) is provided on the top of the circuit board (3). A connecting plate (410) is fixedly connected to each thermal unit (5) near each connecting post (48). A third connecting hole (411) is provided on each connecting plate (410). The connecting plates (410) are respectively arranged on the top surface of the support ring (49) near the connection. The connecting post (48) is fixedly connected in the third connecting hole (411) near the connection.

2. The low-heat-loss pyroelectric infrared sensor according to claim 1, characterized in that: The bottom of the thermal unit (5) is provided with a connection pin (51), the bottom end of the connection pin (51) is soldered to the top surface of the circuit board (3), each of the fixing rods (41) is made of insulating material, and each of the support frames (43) is a Z-shaped structure.

3. The low-heat-loss pyroelectric infrared sensor according to claim 1, characterized in that: Each of the fixed rods (41) has a threaded hole (42) at its top, and each of the support frames (43) has a mounting hole (44) at its top. Each of the support frames (43) has a hidden groove (45) at its top near the mounting hole (44). Each mounting hole (44) is provided with a connecting bolt (46). The support frame (43) is fixedly connected to the fixed rod (41) by using the connecting bolt (46) to pass through the mounting hole (44) and the threaded hole (42). The top of the connecting bolt (46) is respectively located in the hidden groove (45) near the fixed rod.

4. The low-heat-loss pyroelectric infrared sensor according to claim 1, characterized in that: The circuit board (3) is provided with an encapsulation shell (6) on its outer side, and the encapsulation shell (6) is fixedly connected to the top surface of the encapsulation base (1).

5. The low-heat-loss pyroelectric infrared sensor according to claim 4, characterized in that: A packaging cover (8) is fixedly connected to the top surface of the packaging shell (6), and a filter (81) is provided at the center of the packaging cover (8).

6. The low-heat-loss pyroelectric infrared sensor according to claim 4, characterized in that: The packaging base (1) has a plurality of first connection holes (11), and the circuit board (3) has a second connection hole (31) near each of the first connection holes (11). Each of the first connection holes (11) has a main pin (2), and the top of the main pin (2) passes through the adjacent second connection hole (31) and is soldered to the top surface of the circuit board (3).

7. The low-heat-loss pyroelectric infrared sensor according to claim 6, characterized in that: A heat insulation plate (9) is provided between the circuit board (3) and the packaging base (1). The heat insulation plate (9) has a fourth connection hole (91) near each of the first connection holes (11). The main pin (2) passes through the adjacent fourth connection hole (91).

8. The low-heat-loss pyroelectric infrared sensor according to claim 7, characterized in that: A heat insulation layer (7) is fixedly connected to the inner wall of the encapsulation shell (6).

9. The low-heat-loss pyroelectric infrared sensor according to claim 8, characterized in that: Both the heat insulation layer (7) and the heat insulation board (9) are provided with insulating material.

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