Optical path structure of dust sensor

Abstract

The utility model relates to an optical path structure of a dust sensor. The dust sensor light path structure comprises a light-emitting element, a light-receiving element and a light path area, the surfaces of the light-emitting element and the light-receiving element are mounted on the PCB; the PCB is arranged in the circuit board structure; a circuit board structure, wherein the light path area is separated by a separation wall; the dust channel passes through the light path area; optical axes of the light-emitting element and the light-receiving element are perpendicular to the dust channel; the optical axis included angle of the light-emitting element and the light-receiving element is 90 degrees; optical axes of the light-emitting element and the light-receiving element divide a light path area into a 90-degree included angle range and a 90-degree included angle range; a shading wall extending from the partition wall to the dust channel is arranged within the 90-degree range. The included angle between the optical axes of the light-emitting element and the light-receiving element is 90 degrees, so that the dust sensor is simpler and more compact in structure and convenient to assemble.

Description

Technical Field

[0001] This utility model relates to the technical field of dust sensors, and in particular to an optical path structure for a dust sensor. Background Technology

[0002] The most common dust sensors on the market today utilize the principle of light scattering. When light emitted by the light-emitting element shines on dust particles, it is scattered; the light-receiving element receives the scattered light and calculates the dust concentration by detecting the intensity of the scattered light. The dust sensor internally consists of a circuit board structure and an optical path area; both the light-emitting and light-receiving elements are mounted on the circuit board structure; the optical path area also contains a through-flow dust channel; ideally, the light-emitting element emits light into the dust channel; this light is scattered at the dust channel; and the light-receiving element receives the scattered radiation. However, in reality, some of the light emitted by the light-emitting element still bypasses the dust channel and directly reaches the light-receiving element, affecting the detection accuracy of the dust sensor; this portion of light is called stray light. The main purpose of the optical path area is to eliminate stray light interference and improve the detection accuracy of the dust sensor. In existing dust sensors, such as the patent application number 2018202319034, the angle between the optical axes of the light-emitting element and the light-receiving element is usually an obtuse angle to reduce stray light interference. This optical path area results in a complex dust sensor structure design and difficult assembly. Utility Model Content

[0003] The purpose of this invention is to solve the above-mentioned problems and provide an optical path structure for a dust sensor.

[0004] The technical solution of this utility model is: a dust sensor optical path structure, including a light-emitting element, a light-receiving element, and an optical path area; the surfaces of the light-emitting element and the light-receiving element are mounted on a PCB board; both the light-emitting element and the light-receiving element have circuits on the PCB board; the PCB board is set inside the circuit board structure; the circuit board structure and the optical path area are separated by a partition wall, which serves two purposes: firstly, to enclose the optical path area and prevent external light from entering and interfering with the reception of the light-receiving element; and secondly, to prevent light from entering the circuit board structure within the optical path area and affecting the PCB board and the electronic components on the PCB board. The dust channel passes through the optical path area, allowing dust particles to pass through. The optical axes of both the light-emitting element and the light-receiving element are perpendicular to the dust channel, so that light can be reflected onto the dust particles. The optical axes of the light-emitting element and the light-receiving element are at a 90° angle, making the structure of the dust sensor simpler and more compact, and easier to assemble. The optical axes of the light-emitting element and the light-receiving element divide the optical path area into a 90° angle range and an area outside the 90° angle range. A light-shielding wall extending from the partition wall into the dust channel is provided within the 90° angle range. This light-shielding wall can prevent the light-emitting element from shining directly onto the light-receiving element, reducing interference to the light-receiving element.

[0005] Preferably, the optical path area is provided with a dust-passing circular hole that allows the dust channel to pass through; the outer end of the light-shielding wall is close to the dust-passing circular hole to cover the area from the light-emitting element to the dust channel in the optical path area as much as possible, thereby improving the shielding effect of the light-shielding wall.

[0006] Furthermore, the outer end face of the light-shielding wall is a sloped surface that matches the dust-passing circular hole; the inclination direction of this sloped surface is related to the edge direction of the dust-passing circular hole; in this way, even when close to the edge of the dust-passing circular hole, the sloped surface still provides a certain light-shielding effect.

[0007] Preferably, light traps are provided outside the 90° angle range along the edge of the optical path region, which can reduce reflections from the edge of the optical path region to the light receiving element; the light traps point into the optical path region; and light traps are formed between adjacent light traps, which can attenuate stray light after repeated reflections.

[0008] Furthermore, the included angle of the light trap is ≤30° to attenuate stray light and reduce the possibility of stray light hitting the light receiving element.

[0009] Furthermore, the light trapping point on one side of the light-receiving element extends towards the dust-passing circular hole; the light trapping point on one side of the light-receiving element functions similarly to the light-shielding wall, and can block scattered light reflected from outside the 90° angle range.

[0010] Preferably, the optical axis angle between the light-emitting element and the light-receiving element has a tolerance of ±20°, which reduces the difficulty of manufacturing and assembling the dust sensor.

[0011] Preferably, the included angle between the light-emitting element and the light-receiving element can reduce stray light received by the light-receiving element. Neither the light-emitting element nor the light-receiving element has a lens in front of it, which can reduce the number of assembly parts, reduce costs, and improve assembly efficiency.

[0012] Preferably, the light-emitting elements are disposed within the circuit board structure, with a gap between them and the partition wall; stray light emitted by some of the light-emitting elements will be reflected back into the circuit board structure after illuminating the partition wall, without interfering with the light-receiving elements; a backlight wall is also provided within the circuit board structure; the light-emitting elements are embedded in the backlight wall; the backlight wall can prevent stray light from affecting the PCB board and the electronic components on the PCB board, and in conjunction with the partition wall, repeatedly reflect stray light back to the circuit board structure, thus attenuating the stray light.

[0013] Furthermore, the partition wall is provided with a light-transmitting hole coaxial with the optical axis of the light-emitting element; the light emitted by the light-emitting element enters the optical path area through the light-transmitting hole; the light-transmitting hole is a flared opening facing the circuit board structure, which can prevent stray light from entering the optical path area through reflection from the hole wall.

[0014] Furthermore, the circuit board structure is provided with support pillars corresponding to the backlight wall; these support pillars support the PCB board portion where the light-emitting element is located, supporting the light-emitting element and ensuring that the light-emitting element emits light stably.

[0015] Preferably, there are two light-receiving elements, which are symmetrically mounted on the upper and lower surfaces of the PCB board. Two scattered light receiving points are set at the same position along the edge of the optical path area to improve the signal-to-noise ratio and enhance the detection accuracy of the dust sensor.

[0016] The beneficial effects of this utility model are as follows: The optical path structure of the dust sensor of this utility model has the following advantages:

[0017] (1) The optical axis angle between the light-emitting element and the light-receiving element of this utility model is 90°, which makes the structure of the dust sensor simpler and more compact, and easier to assemble;

[0018] (2) The outer end of the light-shielding wall of this utility model is close to the dust passage hole to cover the range from the light-emitting element to the dust channel in the light path area as much as possible, thereby improving the shielding effect of the light-shielding wall; the outer end face of the light-shielding wall is a slope that matches the dust passage hole; even if it is close to the edge of the dust passage hole, the slope will still have a certain light-shielding effect.

[0019] (3) The light trapping angle on one side of the light receiving element of this utility model has a similar function to the light shielding wall, and can block the scattered light reflected from outside the 90° angle range;

[0020] (4) The light-emitting element of this utility model is set inside the circuit board structure and there is a gap between it and the partition wall; some stray light emitted by the light-emitting element will be reflected back into the circuit board structure after being irradiated by the partition wall, and will not interfere with the light-receiving element; the backlight wall can prevent stray light from affecting the PCB board and the electronic components on the PCB board, and cooperates with the partition wall to repeatedly reflect the stray light back to the circuit board structure and attenuate the stray light. Attached Figure Description

[0021] Figure 1 This is a front view of the optical path structure of the dust sensor of this utility model;

[0022] Figure 2 yes Figure 1 AA section view;

[0023] Figure 3 yes Figure 1 BB section view;

[0024] Figure 4 yes Figure 2 CC section view;

[0025] Figure 5 This is a schematic diagram of the optical path structure of the dust sensor of this utility model;

[0026] Figure 4 The BB cutting line in the image coincides with the optical axis of the light-emitting element and the optical axis of the light-receiving element.

[0027] In the diagram: 01. Circuit board structure, 011. PCB board, 012. Gap, 013. Backlight wall, 014. Support column A, 1. Light-emitting element, 2. Light-receiving element, 3. Light path area, 31. Dust channel, 32. Within the 90° angle range, 321. Light-shielding wall, 3212. Sloping surface, 33. Outside the 90° angle range, 331. Light trap corner, 332. Light trap part, 34. Dust passage hole, 4. Separator wall, 41. Support column B, 42. Light transmission hole. Detailed Implementation

[0028] Example 1: See Figure 1-5 A dust sensor optical path area includes a light-emitting element 1, a light-receiving element 2, and an optical path area 3. The light-emitting element 1 and the light-receiving element 2 are mounted on a PCB board 011. Both the light-emitting element 1 and the light-receiving element 2 have circuitry on the PCB board 011. The PCB board 011 is located within a circuit board structure 01. The circuit board structure 01 and the optical path area 3 are separated by a partition wall 4. This partition wall serves two purposes: firstly, to enclose the optical path area 3 and prevent external light from entering and interfering with the light-receiving element 2; and secondly, to prevent light from entering the circuit board structure 01 within the optical path area 3 and affecting the PCB board 011 and its electronic components. A dust channel is also included. 31 passes through the light path region 3, allowing dust particles to pass through the light path region 3; the optical axes of the light-emitting element 1 and the light-receiving element 2 are both perpendicular to the dust channel 31, so that light can be reflected onto the dust particles; the optical axes of the light-emitting element 1 and the light-receiving element 2 are at an angle of 90°, making the structure of the dust sensor simpler and more compact, and easier to assemble; the optical axes of the light-emitting element 1 and the light-receiving element 2 divide the light path region 3 into a 90° angle range 32 and a 90° angle range outside the range 33; within the 90° range, there is a light-shielding wall 321 extending from the partition wall 4 to the dust channel 31; the light-shielding wall 321 can prevent the light-emitting element 1 from shining directly onto the light-receiving element 2, reducing the interference to the light-receiving element 2.

[0029] Compared with the prior art, the optical axis angle between the light-emitting element 1 and the light-receiving element 2 of this utility model is 90°, which makes the structure of the dust sensor simpler and more compact, and easier to assemble.

[0030] The optical path area 3 is provided with a dust passage hole 34 that allows the dust channel 31 to pass through; the outer end of the light shield 321 is close to the dust passage hole 34 to cover the range from the light-emitting element 1 to the dust channel 31 in the optical path area 3 as much as possible, thereby improving the shielding effect of the light shield 321.

[0031] The outer end face of the light-shielding wall 321 is an inclined surface 3212 that matches the dust-passing circular hole 34; the inclination direction of the inclined surface 3212 is related to the edge direction of the dust-passing circular hole 34; in this way, even when close to the edge of the dust-passing circular hole 34, the inclined surface 3212 still has a certain light-shielding effect.

[0032] Outside the 90° angle range, there is a light trapping tip 331 arranged along the edge of the optical path region 3, which can reduce the reflection from the edge of the optical path region 3 to the light receiving element 2; the light trapping tip 331 points into the optical path region 3; and a light trapping portion 332 is formed between adjacent light trapping tips 331, which can attenuate stray light after repeated reflections.

[0033] The included angle of the light trapping portion 332 is ≤30°, which attenuates stray light and reduces the possibility of stray light hitting the light receiving element 2.

[0034] The light trapping angle 331 on one side of the light receiving element 2 extends toward the dust passage 34; the light trapping angle 331 on one side of the light receiving element 2 has a similar function to the light shielding wall 321, and can block the scattered light reflected from outside the 90° angle range 33.

[0035] The optical axis angle between the light-emitting element 1 and the light-receiving element 2 has a tolerance of ±20°, which reduces the difficulty of manufacturing and assembling the dust sensor.

[0036] The angle between the light-emitting element 1 and the light-receiving element 2 can reduce stray light received by the light-receiving element 2. Neither the light-emitting element 1 nor the light-receiving element 2 has a lens in front, which can reduce the number of assembly parts, reduce costs, and improve assembly efficiency.

[0037] The light-emitting element 1 is disposed within the circuit board structure 01, with a gap 012 between it and the partition wall 4; some stray light emitted by the light-emitting element 1 will be reflected back into the circuit board structure 01 after hitting the partition wall 4, without interfering with the light-receiving element 2; a backlight wall 013 is also provided within the circuit board structure 01; the light-emitting element 1 is embedded within the backlight wall 013; see [link to relevant documentation] Figure 5 The backlight wall 013 can prevent stray light from affecting the PCB board 011 and the electronic components on the PCB board 011. On the other hand, in conjunction with the partition wall 4, it can repeatedly reflect stray light back to the circuit board structure 01 and attenuate stray light. Figure 5 In the diagram, the arrow points in the direction of the stray light emitted by the light-emitting element 1, which can show the path of the stray light as it is reflected back and forth within the gap 012.

[0038] The partition wall 4 is provided with a light-transmitting hole 42 coaxial with the optical axis of the light-emitting element 1; the light emitted by the light-emitting element 1 enters the optical path region 3 through the light-transmitting hole; the light-transmitting hole 42 is a flared opening facing the circuit board structure 01, which can prevent stray light from entering the optical path region 3 through reflection from the hole wall of the light-transmitting hole 42. See [reference needed] Figure 2 ; Figure 2 In the diagram, the arrow points in the direction of the stray light, which shows the path of the stray light after it is reflected from the light-transmitting hole 42 at the horn mouth.

[0039] The circuit board structure 01 is provided with a support column 014 corresponding to the backlight wall 013; the support column 014 supports the PCB board 011 where the light-emitting element 1 is located, and supports the light-emitting element 1 to ensure that the light-emitting element 1 emits light stably.

[0040] The working principle of this embodiment: The optical axes of the light-emitting element 1 and the light-receiving element 2 are at a 90° angle, making the structure of the dust sensor simpler and more compact, and easier to assemble; the optical axes of the light-emitting element 1 and the light-receiving element 2 divide the optical path area 3 into a 90° angle range 32 and a 90° angle range outside the range 33; within the 90° range, a light-shielding element extending from the partition wall 4 to the dust channel 31 is provided.

[0041] The light-shielding wall 321 prevents the light-emitting element 1 from shining directly onto the light-receiving element 2, reducing interference to the light-receiving element 2. The outer end of the light-shielding wall 321 is close to the dust passage 34 to cover as much of the area from the light-emitting element 1 to the dust channel 31 within the optical path region 3 as possible, thereby improving the shielding effect of the light-shielding wall 321. The light trapping angle 331 can reduce reflections from the edge of the optical path region 3 to the light-receiving element 2; the light trapping portion 332 can attenuate stray light after repeated reflections; the light trapping angle 331 on one side of the light-receiving element 2 has a similar function to the light-shielding wall 321, and can block scattered light reflected from outside the 90° angle range 33. Some stray light emitted by the light-emitting element 1 will be reflected back into the circuit board structure 01 after shining on the partition wall 4, without interfering with the light-receiving element 2; the backlight wall 013 can prevent stray light from affecting the PCB board 011 and the electronic components on the PCB board 011, and in conjunction with the partition wall 4, repeatedly reflect the stray light that is reflected back to the circuit board structure 01, thus attenuating the stray light.

[0042] Example 2: Example 2 is basically the same as Example 1, and the similarities will not be repeated. The difference is that there are two light-receiving elements 2, which are symmetrically mounted on the upper and lower surfaces of PCB board 011. Two scattered light receiving points are set at the same position along the edge of the light path area 3 to improve the S / N ratio and improve the detection accuracy of the dust sensor.

[0043] The partition wall 4 extends outward to form a support column B 41; the light receiving element 2 is embedded in the support column B 41, which improves the installation stability of the light receiving element 2 and ensures that the light receiving element 2 stably receives the scattered light.

[0044] Outside the 90° angle range 33, a light trap portion 332 is provided on the edge of the optical path region 3 directly opposite the light receiving element 2. Stray light entering the light trap portion 332 is reduced and will not be reflected onto the light receiving element 2, causing interference.

[0045] Outside the 90° angle range 33, a light trap portion 332 is provided along the edge of the optical path region 3 directly opposite the light-emitting element 1. A sloping wall is provided at one corner of the optical path region 3; the sloping wall and the adjacent light trap tip 331 form the light trap portion 332; the stray light intensity emitted directly from the light-emitting element 1 is relatively large, and there is still a possibility that it will be reflected multiple times and reach the light-receiving element 2; the light trap portion 332 can reduce the stray light emitted directly from the light-emitting element 1, so that it will not be reflected to the light-receiving element 2, thus eliminating interference.

Claims

1. A dust sensor optical path structure, comprising a light-emitting element, a light-receiving element, and an optical path region; the surfaces of the light-emitting element and the light-receiving element are mounted on a PCB board; the PCB board is disposed within a circuit board structure; the circuit board structure and the optical path region are separated by a partition wall; a dust channel passes through the optical path region; the optical axes of the light-emitting element and the light-receiving element are both perpendicular to the dust channel; characterized in that, The light-emitting element and the light-receiving element have an optical axis angle of 90°; the optical axis of the light-emitting element and the light-receiving element divides the optical path area into a range within 90° and a range outside 90°; within the 90° range, there is a light-shielding wall extending from the partition wall to the dust channel.

2. The optical path structure of the dust sensor according to claim 1, characterized in that: The optical path area is provided with a dust-passing circular hole that allows dust to pass through; the outer end of the light-shielding wall is close to the dust-passing circular hole.

3. The optical path structure of the dust sensor according to claim 1, characterized in that: Outside the 90° included angle range, there are light traps arranged along the edge of the optical path area; the light traps point into the optical path area; and light trap portions are formed between adjacent light traps.

4. The optical path structure of the dust sensor according to claim 3, characterized in that: The light trap tip on one side of the light-receiving element extends toward the dust-passing circular hole.

5. The optical path structure of the dust sensor according to claim 3, characterized in that: The included angle of the light trap portion is ≤30°.

6. The optical path structure of the dust sensor according to claim 1, characterized in that: The optical axis angle of the light-emitting element and the light-receiving element has a tolerance of ±20°.

7. The optical path structure of the dust sensor according to claim 1, characterized in that: Neither the light-emitting element nor the light-receiving element has a lens in front of it.

8. The optical path structure of the dust sensor according to claim 1, characterized in that: The light-emitting element is set inside the circuit board structure, with a gap between it and the partition wall; the circuit board structure also has a backlight wall; the light-emitting element is embedded in the backlight wall; the partition wall has a light-transmitting hole coaxial with the optical axis of the light-emitting element; the light-transmitting hole is a flared opening facing the circuit board structure.

9. The optical path structure of the dust sensor according to claim 8, characterized in that: The circuit board structure is equipped with support pillars corresponding to the backlight wall; these support pillars support the PCB board portion where the light-emitting element is located.

10. The optical path structure of the dust sensor according to claim 1, characterized in that: There are two light-receiving elements, which are mounted symmetrically on the upper and lower surfaces of the PCB board.

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