A gas concentration infrared sensor

Abstract

This invention belongs to the field of gas detection technology, specifically providing a gas concentration infrared sensor, including a cylindrical body and a circuit board. The circuit board is disposed within the cylindrical body, dividing the cylindrical body into a first space and a second space. An infrared light emitting component is located in the first space, and an infrared detection component is located in the second space. A first reflective component is located in the first space, and a second reflective component is located in the second space. The edge of the circuit board has a notch connecting the first and second spaces, and a third reflective component is located at the notch. The infrared light can be reflected sequentially between the first, third, and second reflective components and transmitted to the infrared detection component. This invention can form a double-layered reflective light path within the cylindrical body, ensuring the light path length while making the outer diameter and thickness of the infrared sensor smaller than a set value, thus achieving a miniaturized design of the infrared sensor.

Description

Technical Field

[0001] This invention belongs to the field of gas detection technology, and specifically provides a gas concentration infrared sensor. Background Technology

[0002] NDIR gas sensors are based on the principle of nondispersive infrared absorption. When infrared light passes through the gas to be measured, the gas molecules absorb infrared light of a specific wavelength. The absorption relationship follows the Lambert-Beer absorption law. Due to the vibration between molecules, gas molecules have different and specific atomic absorption wavelengths in the infrared band. Therefore, the gas concentration can be detected by measuring the absorption of optical energy at a specific wavelength.

[0003] In their prior patent application CN202320487495.X, the inventors provided a mounting groove at the base, within which multiple reflectors were placed. These reflectors were located on the inner wall of the mounting groove and away from the top end cap structure. Infrared light emitted by an infrared emitter was reflected sequentially among the reflectors before entering an infrared detector. As the infrared light traveled along the optical path, it passed through the gas within the mounting groove. By measuring the loss of the infrared light, the gas concentration in the mounting groove was determined. In this technical solution, the transmission optical path of the infrared light was essentially parallel to the circuit board and the end cap at the base; that is, the end cap did not participate in the reflection of the infrared light. This eliminated the need to consider avoiding the optical path at the air inlet at the end cap, allowing for an increase in the number and size of the air inlets.

[0004] The inventors believe that while the above solution is beneficial for reducing the length of the infrared sensor in the direction perpendicular to the circuit board (i.e., the axial direction of the base), it is not conducive to reducing the outer diameter of the infrared sensor in the circumferential direction. The reflector itself needs to occupy a certain volume on the inner wall of the mounting groove. When the number of reflectors is small, it will result in insufficient optical path length; when the number of reflectors is large, the required volume of the mounting groove increases, making the circumferential dimensions of the base and the infrared sensor too large. In other words, this solution is not conducive to achieving a balance between the axial and circumferential dimensions of the gas concentration infrared sensor in the direction perpendicular to the circuit board.

[0005] In addition, although the above technical solution has an air inlet at the end cap of the infrared sensor to connect the mounting slot and the external environment, there are problems with the design of the size and number of the air inlets. Specifically, when the size of the air inlet is small, the air intake is slow, but the air inlet can prevent debris and dust from entering the mounting slot. However, the slow air intake makes the infrared sensor react slowly and unable to quickly achieve measurement. When the size of the air inlet is large, although the air intake is fast and measurement can be performed quickly, the protection of the internal electrical components is poor. Summary of the Invention

[0006] The purpose of this invention is to provide a gas concentration infrared sensor to at least solve one of the above-mentioned technical problems.

[0007] To address the aforementioned problems in the prior art, one or more embodiments of the present invention provide a gas concentration infrared sensor, including a cylindrical body and a circuit board. The cylindrical body has openings at both ends, and the circuit board is disposed within the cylindrical body, dividing the cylindrical body axially into a first space and a second space. An infrared light emitting component is disposed in the first space, and an infrared detection component is disposed in the second space. A first reflective component is disposed in the first space, comprising multiple first reflective elements disposed on the inner wall of the cylindrical body. A second reflective component is disposed in the second space, comprising multiple second reflective elements disposed on the inner wall of the cylindrical body. The edge of the circuit board has a notch connecting the first space and the second space. A third reflective component is disposed at the notch location, comprising multiple third reflective elements. The multiple first reflective elements can receive infrared light emitted by the infrared light emitting component and sequentially reflect the infrared light in the first space before transmitting it to the third reflective element. The third reflective component can transmit the infrared light to the second reflective component, and the multiple second reflective elements can sequentially reflect the infrared light and transmit it to the infrared detection component.

[0008] Furthermore, end caps are fitted at both ends of the cylinder, each end cap comprising a cylinder fitted over the outside of the cylinder and an end cap at the end of the cylinder, the end cap having an air inlet; the cylinder can reciprocate along the axial direction of the cylinder to a compressed state and an expanded state; when in the compressed state, the distance between the end cap and the circuit board is D1; ​​when in the expanded state, the distance between the end cap and the circuit board is D2, D1 <D2。

[0009] Furthermore, an elastic reset element is installed between the two cylinders. The elastic reset element can accumulate elastic potential energy when the cylinder moves toward the circuit board to reach a compressed state, and release elastic potential energy when the cylinder moves away from the circuit board and reaches an expanded state.

[0010] Furthermore, the elastic restoring element includes a spring, which has no elastic force when the cylinder is in an expanded state; and accumulates elastic potential energy when the cylinder is in a compressed state.

[0011] Furthermore, the cylinder includes a rigid part and elastic parts respectively disposed at both ends of the rigid part. The end of the elastic part away from the rigid part has an end cap and an air inlet. The rigid part is provided with a first reflective component, a second reflective component and a circuit board.

[0012] Furthermore, the first reflector of the first reflective assembly is divided into a concave mirror and a plane mirror, the second reflective assembly includes a concave mirror and a plane mirror, and the third reflector is a plane mirror.

[0013] Furthermore, the first reflective component includes at least one first concave mirror and a plurality of first plane mirrors arranged sequentially along the optical path and with the reflective surface perpendicular to the circuit board. The first plane mirror at the very end of the optical path is used to transmit infrared light parallel to the circuit board to the third reflective component.

[0014] Furthermore, the third reflective component includes a second plane mirror in the first space and a third plane mirror in the second space. The second plane mirror and the third plane mirror face the circuit board and are both at an angle of 45 degrees to the circuit board. The second plane mirror can receive infrared light reflected by the first reflective component that is parallel to the circuit board and transmit the infrared light to the third plane mirror in a direction perpendicular to the circuit board. The third plane mirror can receive infrared light in a direction perpendicular to the circuit board and transmit the infrared light to the second reflective component in a horizontal direction.

[0015] Furthermore, the second reflective component includes a plurality of fourth plane mirrors arranged sequentially along the optical path and whose reflective surfaces are perpendicular to the circuit board, and at least one second concave mirror, the second concave mirror reflecting infrared light to the infrared detection component.

[0016] Furthermore, the first reflector, the second reflector, and the third reflector are formed by the protrusions and concave surfaces of the inner wall of the cylinder facing the inner cavity of the cylinder, and the protrusions and concave surfaces are coated with a reflective coating to form a reflective surface.

[0017] The beneficial effects of one or more of the above technical solutions:

[0018] In this design, by placing the reflector on the inner wall of the cylinder, the reflection of infrared light inside the cylinder is essentially parallel to the circuit board. Compared to the reflection of infrared light between the circuit board and the end cap, this significantly reduces the size of the infrared sensor along the direction perpendicular to the circuit board. To avoid excessive circumferential dimensions of the cylinder due to too many reflectors, the first and second reflector components are arranged in layers, with a third reflector component forming a complete optical path. Compared to using a single-layer reflector component, this effectively reduces the circumferential size of the infrared sensor without significantly increasing its size along the direction perpendicular to the circuit board. This achieves a balance between the vertical and circumferential dimensions of the infrared sensor, facilitating miniaturization of the infrared sensor design.

[0019] In this solution, when the end cap moves from the direction closest to the circuit board to the direction furthest from the circuit board, the size of the air chamber formed by the end cap, cylinder, body and circuit board will increase and the air pressure will decrease. As a result, under the pressure difference between the inside and outside, outside air will quickly enter the air chamber, enabling the infrared sensor to quickly measure the gas concentration. Thus, the air intake speed no longer depends on the size and number of air intake holes.

[0020] This design incorporates an elastic reset component that accumulates elastic potential energy when the cylinder reaches a compressed state and releases it when the cylinder reaches an expanded state. This design helps reduce the difficulty of reciprocating movement of the cylinder and end cap along the cylinder's axial direction.

[0021] In this design, the cylinder includes a rigid part and an elastic part. The elastic part has an end cap. The elastic part, rigid part, end cap, and circuit board in the cylinder form a gas chamber. By pressing the elastic part, the volume of the gas chamber can be changed. This allows the gas pressure to change as the gas chamber volume increases. Under the action of the external gas pressure difference, the gas enters the gas chamber, facilitating rapid measurement of gas concentration.

[0022] In this design, the first reflector, the second emitter, and the third reflector are all formed by the protrusions and concave surfaces of the inner wall of the cylinder facing the inner cavity of the cylinder. This arrangement omits the installation process of the first, second, and third reflectors, avoids the problem of decreased measurement accuracy caused by errors in the installation position of each reflector, and facilitates the miniaturization design of the infrared sensor. Attached Figure Description

[0023] The following description refers to the accompanying drawings, in which:

[0024] Figure 1 This is a schematic diagram of a structure such as a first reflective component disposed in the first space in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of a structure such as a second reflective component disposed in the second space in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure with end caps at both ends of the cylinder in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the structure with elastic portions at both ends of the cylinder in an embodiment of the present invention.

[0028] List of reference numerals in the attached diagram: 1. Cylinder; 2. Secondary plane mirror; 3. Circuit board; 4. Tertiary plane mirror; 5. Notch; 6. Primary plane mirror; 7. Infrared light emitting component; 8. Primary concave mirror; 9. Quaternary plane mirror; 10. Pentium plane mirror; 11. Secondary concave mirror; 12. Infrared detection component; 13. Sixth-level plane mirror; 14. Cylinder; 1401. Air inlet; 101. Spring; 102. Rigid part; 103. Elastic part. Detailed Implementation

[0029] Those skilled in the art should understand that the embodiments described below are merely preferred embodiments of this application, and these preferred embodiments are only used to explain the technical principles of this application and are not intended to limit the scope of protection of this application.

[0030] It should be noted that in the description of this application, terms such as "center," "upper," "lower," "top," "bottom," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can also refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0032] like Figures 1-4 As shown, a gas concentration infrared sensor includes a cylinder 1 and a circuit board 3. The cylinder 1 has openings at both ends, and the circuit board 3 is disposed inside the cylinder 1. The circuit board 3 divides the cylinder 1 axially into a first space and a second space. An infrared light emitting component 7 is disposed in the first space, and an infrared detection component 12 is disposed in the second space. A first reflective component is disposed in the first space, and the first reflective component includes multiple first reflective elements disposed on the inner wall of the cylinder 1. A second reflective component is disposed in the second space, and the second reflective component includes multiple second reflective elements disposed on the inner wall of the cylinder 1. The edge of the circuit board 3 has a notch 5, which connects the first space and the second space. A third reflective component is disposed at the notch 5, and the third reflective component includes multiple third reflective elements.

[0033] Multiple first reflectors can receive infrared light emitted by infrared light emitting component 7 and reflect the infrared light in the first space in sequence to transmit it to third reflector. Third reflector can transmit infrared light to second reflector. Multiple second reflectors can reflect infrared light in sequence and transmit the infrared light to infrared detection component 12.

[0034] In this embodiment, end caps are respectively fitted at both ends of the cylinder 1. The end caps include a cylinder 14 fitted outside the cylinder 1 and an end cap at the end of the cylinder 14. The end cap has an air inlet 1401. The cylinder 14 can reciprocate along the axial direction of the cylinder 1 to a compressed state and an expanded state. When in the compressed state, the distance between the end cap and the circuit board 3 is D1; ​​when in the expanded state, the distance between the end cap and the circuit board 3 is D2. <D2。

[0035] Specifically, the end cap, the cylinder 1, and the circuit board 3 respectively form an air chamber in the first space and the second space.

[0036] In this embodiment, an elastic reset member is installed between the two cylinders 14. The elastic reset member can accumulate elastic potential energy when the cylinder 14 moves toward the circuit board 3 to reach the compressed state, and release the elastic potential energy when the cylinder 14 moves away from the circuit board 3 and reaches the expanded state.

[0037] In this embodiment, the elastic reset member includes a spring 101. When the cylinder 14 is in an expanded state, the spring 101 has no elastic force; when the cylinder 14 is in a compressed state, the spring 101 is subjected to accumulated elastic potential energy.

[0038] In this embodiment, the cylinder 1 includes a rigid part 102 and elastic parts 103 respectively disposed at both ends of the rigid part 102. The end of the elastic part 103 away from the rigid part 102 has an end cap and an air inlet 1401. The rigid part 102 is provided with a first reflective component, a second reflective component and a circuit board 3.

[0039] Specifically, the end cap, the cylinder 1, and the circuit board 3 respectively enclose an air chamber in the first space and the second space.

[0040] In this embodiment, the first reflector of the first reflective assembly is divided into a concave mirror and a plane mirror, the second reflective assembly includes a concave mirror and a plane mirror, and the third reflector is a plane mirror.

[0041] In this embodiment, the first reflective component includes at least one first concave mirror and a plurality of first plane mirrors arranged sequentially along the optical path and whose reflective surfaces are perpendicular to the circuit board 3. The first plane mirror at the end of the optical path is used to transmit infrared light parallel to the circuit board 3 to the third reflective component.

[0042] As a specific structural form, such as Figure 1 As shown, the first reflecting component includes a first concave mirror (i.e., the first-stage concave mirror 8 shown in the figure), and the first reflecting component also includes two first plane mirrors (i.e., the first-stage plane mirror 66 and the second-stage plane mirror 2 shown in the figure); the infrared light emitted by the infrared light emitting component 7 can be directed towards the first-stage concave mirror 8, and then the first-stage concave mirror 8 converges the diverging light and directs it towards the first-stage plane mirror 66, the first-stage plane mirror 66 directs the infrared light towards the second-stage plane mirror 2, and the second-stage plane mirror 2 directs the light towards the third reflecting component.

[0043] In this embodiment, the third reflective component includes a second plane mirror located in the first space and a third plane mirror located in the second space. The second plane mirror and the third plane mirror are respectively facing the circuit board 3 and are at an angle of 45 degrees to the circuit board 3. The second plane mirror can receive infrared light reflected by the first reflective component that is parallel to the circuit board 3 and transmit the infrared light to the third plane mirror in a direction perpendicular to the circuit board 3. The third plane mirror can receive infrared light in a direction perpendicular to the circuit board 3 and transmit the infrared light to the second reflective component in a horizontal direction.

[0044] Specifically, the second plane mirror here is the tertiary plane mirror 4 shown in the diagram, and the third plane mirror is the quaternary plane mirror 9 shown in the diagram. The tertiary plane mirror 4 and the quaternary plane mirror 9 are arranged opposite each other, and the projections of the tertiary plane mirror 4 and the quaternary plane mirror 9 toward the circuit board 3 fall within the outer contour of the notch 5 in the circuit board 3. The tertiary plane mirror 4 can receive the infrared light from the secondary plane mirror 2 and reflect the light to the quaternary plane mirror 9, and the quaternary plane mirror 9 reflects the infrared light to the third reflective component.

[0045] In this embodiment, the second reflective component includes a plurality of fourth plane mirrors arranged sequentially along the optical path and whose reflective surfaces are perpendicular to the circuit board 3, and at least one second concave mirror. The second concave mirror reflects infrared light to the infrared detection component 12.

[0046] As a specific structural form, there are two fourth plane mirrors, namely the fifth-order plane mirror 10 and the sixth-order plane mirror 13, and one second concave mirror, namely the second-order concave mirror 11.

[0047] At this time, the fifth-order plane mirror 10 receives the infrared light transmitted by the fourth-order plane mirror 9, and then reflects the infrared light to the sixth-order plane mirror 13. The sixth-order plane mirror 13 reflects the infrared light to the second-order concave mirror 11. The second-order concave mirror 11 converges the infrared light and transmits it to the infrared detection component 12. The infrared detection component 12 receives the infrared light after multiple reflections.

[0048] In this embodiment, the first reflector, the second reflector and the third reflector are formed by the protrusions and concave surfaces of the inner wall surface of the cylinder 1 facing the inner cavity of the cylinder 1, and the protrusions and concave surfaces are coated with a reflective coating to form a reflective surface.

[0049] Working principle:

[0050] When using this device, the volume of the air chamber is reduced by pressing the end cap. After releasing the end cap, the air chamber becomes larger and the air pressure inside the air chamber decreases. Under the action of atmospheric pressure, the outside gas quickly enters the air chamber. After repeating the process of pressing and releasing the end cap multiple times, the composition of the gas inside the air chamber is basically the same as that of the gas in the outside environment.

[0051] Infrared light emitting component 7 is activated. Infrared light passes through the gas in the gas chamber. After multiple reflections, the infrared light enters infrared detection component 12. Infrared detection component 12 obtains the gas concentration value by detecting the loss of infrared light.

[0052] The technical solutions of this application have been described in conjunction with the preferred embodiments above. However, it will be readily understood by those skilled in the art that the scope of protection of this application is not limited to the above preferred embodiments. Without departing from the technical principles of this application, those skilled in the art can disassemble and combine the technical solutions in the above preferred embodiments, and can also make equivalent changes or substitutions to the relevant technical features. Any changes, equivalent substitutions, improvements, etc., made within the technical concept and / or technical principles of this application will fall within the scope of protection of this application.

Claims

1. A gas concentration infrared sensor, characterized in that, include A cylindrical body with openings at both ends; A circuit board is disposed in the cylinder, which divides the cylinder into a first space and a second space along the axial direction. An infrared light emitting component is provided in the first space, and an infrared detection component is provided in the second space. The first space is provided with a first reflective component, which includes a plurality of first reflective elements disposed on the inner wall of the cylinder; the second space is provided with a second reflective component, which includes a plurality of second reflective elements disposed on the inner wall of the cylinder; the edge of the circuit board has a notch, which connects the first space and the second space; a third reflective component is provided at the notch location, which includes a plurality of third reflective elements. The plurality of first reflectors can receive infrared light emitted by the infrared light emitting component and reflect the infrared light in the first space in sequence and transmit it to the third reflector. The third reflector can transmit the infrared light to the second reflector. The plurality of second reflectors can reflect the infrared light in sequence and transmit the infrared light to the infrared detection component. Both ends of the cylinder are fitted with end caps, each end cap comprising a cylinder fitted over the outside of the cylinder and an end cap at the end of the cylinder, the end cap having an air inlet. The cylinder can reciprocate along the axial direction of the cylinder to a compressed state and an expanded state. When in the compressed state, the distance between the end cap and the circuit board is D1; ​​when in the expanded state, the distance between the end cap and the circuit board is D2. <D2; An elastic reset element is installed between the two cylinders. The elastic reset element can accumulate elastic potential energy when the cylinder moves toward the circuit board to reach a compressed state, and release elastic potential energy when the cylinder moves away from the circuit board and reaches an expanded state. The cylinder includes a rigid part and elastic parts respectively disposed at both ends of the rigid part. The end of the elastic part away from the rigid part has an end cap and an air inlet. The rigid part is provided with a first reflective component, a second reflective component and a circuit board.

2. The gas concentration infrared sensor according to claim 1, characterized in that, The elastic reset element includes a spring. When the cylinder is in the expanded state, the spring has no elastic force; when the cylinder is in the compressed state, the spring is subjected to accumulated elastic potential energy.

3. The gas concentration infrared sensor according to claim 1, characterized in that, The first reflective element of the first reflective assembly is divided into a concave mirror and a plane mirror, the second reflective assembly includes a concave mirror and a plane mirror, and the third reflective element is a plane mirror.

4. The gas concentration infrared sensor according to claim 1 or 3, characterized in that, The first reflective component includes at least one first concave mirror and a plurality of first plane mirrors arranged sequentially along the optical path and with the reflective surface perpendicular to the circuit board. The first plane mirror at the end of the optical path is used to transmit infrared light parallel to the circuit board to the third reflective component.

5. The gas concentration infrared sensor according to claim 1 or 3, characterized in that, The third reflective component includes a second plane mirror in the first space and a third plane mirror in the second space. The second plane mirror and the third plane mirror face the circuit board and are both at an angle of 45 degrees to the circuit board. The second plane mirror can receive infrared light parallel to the circuit board reflected by the first reflective component and transmit the infrared light to the third plane mirror in a direction perpendicular to the circuit board. The third plane mirror can receive infrared light in a direction perpendicular to the circuit board and transmit the infrared light to the second reflective component in a horizontal direction.

6. The gas concentration infrared sensor according to claim 1 or 3, characterized in that, The second reflective component includes a plurality of fourth plane mirrors arranged sequentially along the optical path and whose reflective surfaces are perpendicular to the circuit board, and at least one second concave mirror, the second concave mirror reflecting infrared light to the infrared detection component.

7. The gas concentration infrared sensor according to claim 1, characterized in that, The first reflector, the second reflector and the third reflector are formed by the protrusions and concave surfaces of the inner wall of the cylinder facing the inner cavity of the cylinder, and the protrusions and concave surfaces are coated with a reflective coating to form a reflective surface.

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