Detection device

Abstract

The detection device comprises a base, a conveying assembly and an optical fiber sensing assembly, the conveying assembly comprises transmission wheels and a conveying belt, the transmission wheels are in transmission connection to the base, the conveying belt is connected to the multiple transmission wheels in a sleeving mode, the conveying belt is used for bearing and conveying PCBs, and a through groove is formed in the conveying belt in the conveying direction; the optical fiber sensing assembly comprises a main shell and an optical fiber head, the main shell is arranged on the base, the optical fiber head is right opposite to the penetrating groove, and the optical fiber head is flush with the bearing face of the conveying belt so that the PCB on the bearing face of the conveying belt can be detected. According to the detection device provided by the invention, the optical fiber sensing assembly is built in, so that the optical fiber head passes through the through groove in the conveyor belt and can sense the PCB right above the optical fiber head from the interior of the conveyor belt, and thus the strength and stability of a detection signal are greatly enhanced. The optical fiber assembly is embedded in the through groove of the conveyor belt, so that the accuracy of detecting the existence state of the PCB can be improved.

Description

Technical Field

[0001] This invention relates to the field of detection technology, and in particular to a detection device. Background Technology

[0002] In the fields of electronics manufacturing and semiconductors, the automated production and inspection of thin, sheet-like workpieces (such as PCBA boards with a thickness of ≤2mm) is crucial. Currently, the industry commonly uses traditional assembly lines combined with photoelectric sensors for in-situ inspection. However, this conventional technical solution has significant limitations. First, in terms of installation, sensors are usually deployed side-mounted or suspended above the conveyor belt, resulting in an angle between the sensing beam and the workpiece plane. For ultra-thin workpieces, unavoidable minor vibrations or positional shifts during transport can easily lead to ineffective beam blocking, resulting in missed detections. Second, ordinary photoelectric sensors have unstable sensitivity for thinner workpieces; signal changes are weak for extremely thin workpieces, and signal jitter is prone to occur for workpieces with critical thicknesses, leading to a high false alarm rate. Thin PCBA boards, due to their lightweight and weak rigidity, are prone to drifting under conveyor belt vibration. The lack of linkage between traditional blocking structures and detection units further amplifies positional uncertainty, resulting in insufficient detection reliability. Frequent fault alarms severely restrict production pace and quality control efficiency. Therefore, the market urgently needs an inspection device capable of stably inspecting PCB boards. Summary of the Invention

[0003] Based on this, this application provides a detection device that can improve the accuracy of detecting the presence of PCB boards by embedding an optical fiber assembly in the through slot of a conveyor belt.

[0004] A detection device includes a base, a conveying assembly, and an optical fiber sensing assembly. The conveying assembly includes drive wheels and a conveyor belt. The drive wheels are tractively connected to the base, and the conveyor belt is sleeved on multiple drive wheels. The conveyor belt carries and conveys PCB boards, and has a through-slot along the conveying direction. The optical fiber sensing assembly includes a main housing and an optical fiber head. The main housing is disposed on the base, and the optical fiber head faces the through-slot and is flush with the bearing surface of the conveyor belt to detect PCB boards on the bearing surface of the conveyor belt.

[0005] In the detection device, by embedding the fiber optic sensing component, the fiber optic head passes through a through-slot on the conveyor belt, and the sensing surface is set flush with the conveyor belt's bearing surface. This allows the fiber optic head to sense the PCB board directly above it from inside the conveyor belt, significantly enhancing the strength and stability of the detection signal. For thin workpieces prone to displacement due to vibration, this coplanar detection method ensures that even with slight warping or shaking of the PCB board, its main body can reliably block or reflect the signal, effectively avoiding missed detections and false judgments caused by changes in distance or PCB board tilt, significantly improving the reliability and accuracy of the detection. By embedding the fiber optic component within the through-slot of the conveyor belt, the accuracy of detecting the presence of the PCB board can be improved.

[0006] In one embodiment, the fiber optic head is located at the end of the conveyor belt.

[0007] In one embodiment, the conveyor belt has a first end and a second end opposite to each other, and the first end and the second end are respectively provided with an optical fiber head.

[0008] In one embodiment, the optical fiber heads located at both ends of the conveyor belt are positioned opposite each other along the conveying direction of the conveyor belt.

[0009] In one embodiment, the through slot is located in the middle region of the conveyor belt in the width direction.

[0010] In one embodiment, the fiber optic head is located in the through slot.

[0011] In one embodiment, the through groove extends along the length of the conveyor belt.

[0012] In one embodiment, the depth of the through slot is 0.5 to 0.8 times the thickness of the PCB board.

[0013] In one embodiment, the main housing has an installation groove, the opening of which is opposite to the conveyor belt, and the optical fiber head is installed in the installation groove. The main housing has a concave or inclined surface structure on the surface where the groove is opened. The end shape of the conveyor belt is adapted to the concave or inclined surface structure, and the end of the conveyor belt is located in the concave or inclined surface structure and forms a gap.

[0014] In one embodiment, a cover is provided at intervals above the conveyor belt, the cover covering the bearing surface. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0016] Figure 1This is a schematic diagram of the structure of a detection device according to one embodiment; Figure 2 As an example Figure 1 Enlarged view of the area indicated by the dashed line; Figure 3 This is a schematic diagram of the structure of a detection device according to one embodiment; Figure 4 As an example Figure 3 Enlarged view of the area indicated by the dashed line.

[0017] Figure label: Detection device 100; PCB board 101; base 200; conveying assembly 300; drive wheel 310; conveyor belt 320; through groove 321; bearing surface 330; cover 340; fiber optic sensing assembly 400; main housing 410; mounting groove 411; fiber optic head 420; conveying direction P1. Detailed Implementation

[0018] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0019] In the description of this invention, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0020] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0021] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to a fixed connection, a detachable connection, or an integrally formed connection; they can refer to a mechanical connection; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0022] In the fields of electronics manufacturing and semiconductors, the automated production and inspection of thin, sheet-like workpieces (such as PCBA boards with a thickness of ≤2mm) is crucial. Currently, the industry commonly uses traditional assembly lines combined with photoelectric sensors for in-situ inspection. However, this conventional technical solution has significant limitations. First, in terms of installation, sensors are usually deployed side-mounted or suspended above the conveyor belt, resulting in an angle between the sensing beam and the workpiece plane. For ultra-thin workpieces, unavoidable minor vibrations or positional shifts during transport can easily lead to ineffective beam blocking, resulting in missed detections. Second, ordinary photoelectric sensors have unstable sensitivity for thinner workpieces; signal changes are weak for extremely thin workpieces, and signal jitter is prone to occur for workpieces with critical thicknesses, leading to a high false alarm rate. Thin PCBA boards, due to their lightweight and weak rigidity, are prone to drifting under conveyor belt vibration. The lack of linkage between traditional blocking structures and detection units further amplifies positional uncertainty, resulting in insufficient detection reliability. Frequent fault alarms severely restrict production pace and quality control efficiency. Therefore, the market urgently needs an inspection device capable of stably inspecting PCB boards.

[0023] See Figures 1-4To address the aforementioned problems, this application provides a detection device 100. The detection device 100 can be used to detect a PCB board 101. By combining a mechanical structure with fiber optic sensing, the detection device 100 can achieve non-contact detection of the PCB board 101, overcoming the deficiencies in the prior art. Specifically, the detection device 100 includes a base 200, a conveying assembly 300, and a fiber optic sensing assembly 400. The conveying assembly 300 includes a drive wheel 310 and a conveyor belt 320. The drive wheel 310 is tractively connected to the base 200. On the base 200, a conveyor belt 320 is fitted onto multiple drive wheels 310. The conveyor belt 320 carries and transports the PCB board 101. A through-slot 321 is formed along the transport direction P1 on the conveyor belt 320. The fiber optic sensing assembly 400 includes a main housing 410 and a fiber optic head 420. The main housing 410 is mounted on the base 200. The fiber optic head 420 faces the through-slot 321 and is flush with the bearing surface 330 of the conveyor belt 320 to detect the PCB board 101 on the bearing surface 330 of the conveyor belt 320. By embedding the fiber optic assembly within the through-slot 321 of the conveyor belt 320, the detection device 100 improves the accuracy of detecting the presence of the PCB board 101.

[0024] Specifically, in this embodiment, the detection device 100 includes a base 200, a transmission assembly 300, and an optical fiber sensing assembly 400. The transmission assembly 300 includes drive wheels 310 and a conveyor belt 320. The drive wheels 310 are driveably connected to the base 200, and the conveyor belt 320 is sleeved on multiple drive wheels 310. Further, the multiple drive wheels 310 are drively connected to the base 200 via bearings. It should be noted that at least one of the multiple drive wheels 310 is a driving wheel, driven by a drive motor, while the others are driven wheels or tensioning wheels, together forming a stable transmission frame. In one embodiment, the drive motor can be a servo motor or a stepper motor. The conveyor belt 320 is sleeved on the aforementioned drive wheels 310, forming a closed-loop transmission path. The base 200, as the basic support structure of the entire device, provides a stable and reliable mounting platform for the conveyor belt 320 and the optical fiber sensing assembly 400. The conveyor belt 320 is mounted on the base 200. The conveyor belt 320 can carry the PCB board 101 to be inspected and smoothly transport the PCB board 101 to the inspection station according to a preset direction and speed. The surface of the conveyor belt 320 is the bearing surface 330 for carrying the PCB board 101. Motor power is transmitted to the conveyor belt 320 through the drive wheel, thereby achieving smooth and accurate transport of the PCB board 101. The fiber optic sensing assembly 400 enables the inspection function of the inspection device 100. Specifically, in some embodiments, the fiber optic sensing assembly 400 consists of a main housing 410 and a fiber optic head 420. The main housing 410 is fixedly mounted on the base 200. The interior of the main housing 410 integrates optical and electronic components, and the fiber optic head 420 is the end component for performing optical inspection. By integrating the fiber optic sensing component 400, the fiber optic head 420 passes through the through slot 321 on the conveyor belt 320, and the sensing surface is set flush with the bearing surface 330 of the conveyor belt 320. This allows the fiber optic head 420 to sense the PCB board 101 directly above it from inside the conveyor belt 320, thereby greatly enhancing the strength and stability of the detection signal. For thin workpieces that are prone to displacement due to vibration, this coplanar detection method ensures that even if the PCB board has slight warping or shaking, its main body can still reliably block or reflect the signal, effectively avoiding missed detections and misjudgments caused by changes in distance or PCB board tilt, significantly improving the reliability and accuracy of the detection.

[0025] Furthermore, the conveyor belt 320 has through slots 321 along the conveying direction P1. These through slots 321 serve as channels for optical fiber signal transmission. In some embodiments, multiple through slots 321 may also be formed along the conveying direction P1. The optical fiber head 420 is directly opposite the through slot 321, allowing for precise positioning so that it is directly aligned with the through slot 321 on the conveyor belt 320. The front sensing surface of the optical fiber head 420 is at the same horizontal level as the surface of the PCB board 101 (i.e., the bearing surface 330) on the conveyor belt 320. In other words, the front sensing surface of the optical fiber head 420 is flush with the bearing surface 330. This flush structure ensures that when the PCB board 101 is conveyed over the optical fiber head 420, the optical fiber head 420 can accurately sense and detect its bottom surface or specific features through the through slots 321 without contacting the PCB board 101. This includes detecting the presence, position, holes, or specific markings of the board.

[0026] Furthermore, in this embodiment, the fiber optic head 420 is positioned at the end of the conveyor belt 320. When the conveyor belt 320 carrying the PCB board 101 reaches the end and is about to leave the device or enter the next process, the fiber optic head 420 will detect the PCB board 101 through the through slot 321. In one embodiment, when the PCB board 101 is about to leave the robotic gripping area or stacking area, the fiber optic head 420 will detect the PCB board 101 through the through slot 321 to confirm whether the PCB board 101 has arrived completely and is about to leave the end of the conveyor belt 320. This can effectively prevent empty gripping or missing objects in subsequent automated operations. At the same time, the identification by the fiber optic head 420 can ensure that the PCB board 101 passes through the entire process in a complete form, rather than being broken or partially left behind due to accidents during the transport process. In one embodiment, the system only allows a new PCB board 101 to enter the beginning of the conveyor belt 320 or allows the robotic arm to perform the next operation after the end fiber optic head 420 confirms that the PCB board 101 has left normally, thereby avoiding the risk of congestion or collision at the end. By detecting the end position, the possibility of missed detection, misjudgment, and process chaos in the detection device 100 is effectively reduced, ensuring smooth and orderly production and improving the accuracy of detecting the presence status of PCB board 101.

[0027] In one embodiment, the conveyor belt 320 has a first end and a second end, for example, the first end is the entry side of the PCB board 101, and the second end is the exit side of the PCB board 101. Further, an independent set of fiber optic connectors 420 is provided at each of the first and second ends. The fiber optic connector 420 at the first end has a loading confirmation function, capable of detecting in real time whether a new PCB board 101 has been correctly placed on the bearing surface 330 of the conveyor belt 320, and accurately triggering the counting and process start signal of the detection device 100. Further, confirming that the PCB board 101 has entered the detection section provides the detection device 100 with an initial time reference for the PCB board 101, which can be used to trigger subsequent timing. The fiber optic connector 420 at the second end can confirm the exit of the PCB board 101. The detection device 100 can track the entry and exit of the PCB board 101, improving the working efficiency of the production line.

[0028] Furthermore, in this embodiment, the fiber optic heads 420 located at both ends of the conveyor belt 320 are arranged opposite each other along the conveying direction P1 of the conveyor belt 320. One fiber optic head 420 serves as the emitting end of the light source, and the other serves as the receiving end. The light beam emitted by the emitting end passes through the through-slot 321 on the conveyor belt 320 and is received by the receiving end directly opposite it. When the PCB board 101 moves on the conveyor belt 320 and passes between the two fiber optic heads 420, the PCB board 101 briefly cuts off this light beam path. Since the light beam spans the entire width of the conveyor belt 320, the light beam is only reconnected when the PCB board 101 has completely passed through. This allows the detection device 100 to determine whether the length of the PCB board 101 meets the standard or whether there are serious defects. At the same time, unlike the prior art method of detecting reflected light from above, the through-beam detection of this solution relies on whether the light beam is physically blocked. Therefore, even if the PCB board 101 is slightly warped, tilted, or vibrates on the conveyor belt 320, as long as it is still within the light beam path, it will not affect the stability of the detection results. For thin PCB boards 101 that are prone to deformation, this greatly improves the anti-interference capability of the detection device 100.

[0029] In one embodiment, the through slot 321 is located in the middle region of the conveyor belt 320 in the width direction, enabling the detection device 100 to be compatible with PCB boards 101 of different sizes during use. During detection, the width of the PCB boards 101 often varies. By opening the through slot 321 on the center line of the conveyor belt 320's width, regardless of the width of the PCB board 101, when placed on the conveyor belt 320, the physical center axis of the PCB board 101 has a very high probability of coinciding with or being close to the center axis of the conveyor belt 320. This ensures that the main body of the PCB board 101 can always cover or pass through the through slot 321 located in the middle region, thereby being effectively detected by the fiber optic head 420, greatly improving the device's adaptability to workpieces of different sizes. Furthermore, when the PCB board 101 is running on the conveyor belt 320, its central part has the smallest vibration amplitude and the most stable posture. Detection at this location can minimize signal fluctuations caused by slight warping and shaking of the edges of the PCB board 101 during transport, thereby improving the accuracy of detecting the presence of the PCB board 101.

[0030] Furthermore, in this embodiment, the fiber optic head 420 is located within the through-slot 321, resulting in a small distance between the fiber optic head 420 and the bottom surface of the PCB board 101 directly above it. In the detection device 100, the fiber optic signal strength is inversely proportional to the square of the distance. Placing the fiber optic head 420 within the through-slot 321 achieves a near-zero detection distance, resulting in a strong initial signal. At this point, the energy attenuation of both emitted and received light is reduced to a very low level. This allows the system to extremely sensitively capture weak edge features, tiny holes, or subtle height changes on the PCB board 101, and even stably detect extremely thin or translucent PCB boards 101, fundamentally solving the problems of weak signal and misjudgment caused by distance.

[0031] In one embodiment, the interior of the through-slot 321 forms a relatively enclosed detection environment. The sensing surface of the built-in fiber optic head 420 is protected by the wall of the through-slot 321, effectively shielding it from stray light, dust, and electromagnetic interference from other parts of the production line, ensuring the purity and stability of the detection signal. This design is suitable for complex industrial environments and enables stable detection.

[0032] In one embodiment, the through-slot 321 extends along the length of the conveyor belt 320. In another embodiment, the through-slot 321 is an elongated opening, providing a continuous detection window for the fiber optic head 420. As the PCB board 101 moves on the conveyor belt 320, the fiber optic head 420 can continuously scan the bottom of the PCB board 101 to continuously monitor its status over a certain distance. Through specific programming, targeted detection of specific areas of the board can be achieved, greatly enhancing the flexibility and functionality of the detection device 100 during detection.

[0033] Furthermore, in this embodiment, for PCB boards 101 of varying sizes, a single point detection window might miss detection due to slight offset or tilt of the board. The elongated longitudinal through-slot 321 ensures that regardless of the position of the PCB board 101 in the width direction of the conveyor belt 320, as long as the length direction of the PCB board 101 aligns with the conveying direction P1, its main body will cover and pass directly above the fiber optic head 420 during movement, thus being detected and eliminating detection blind spots. In other words, during point detection, when the edge of the PCB board 101 is precisely at the critical position of the detection point, the sensor signal may be in an unstable flickering state, leading to system misjudgment. The longitudinal through-slot 321 provided in this application provides a spatial buffer, making the transition between the entry and exit states of the PCB board 101 clearer and effectively avoiding signal jitter caused by critical positions. Moreover, in scenarios where the conveyor belt 320 operates at high speed, instantaneous point detection may result in missed detection due to insufficient response time. In contrast, the longitudinal through-slot 321 can extend the effective detection time window, allowing the fiber optic head 420 more time to sense and process signals from the passing PCB board 101, thereby ensuring detection reliability under high-speed production cycles.

[0034] Furthermore, the depth of the through-slot 321 is 0.5 to 0.8 times the thickness of the PCB board 101. In one embodiment, the depth of the through-slot 321 can be 0.5 times the thickness of the PCB board 101, and in another embodiment, the depth of the through-slot 321 can be 0.8 times the thickness of the PCB board 101. It should be noted that limiting the slot depth to within 0.8 times the thickness of the PCB board 101 ensures that when the PCB board 101 crosses the slot opening of the through-slot 321, there is still a sufficiently wide conveyor belt 320 surface on both sides to provide stable support, effectively preventing bending, vibration, or even jamming of thin or flexible PCB boards 101 due to sudden loss of support below. At the same time, an excessively deep slot opening of the through-slot 321 would cause the edges of the PCB board 101 to bear greater stress when crossing, posing a potential risk of physical damage to the fragile circuit board. Therefore, the upper limit of 0.8 times provides a safe transition area for the edges of the PCB board 101.

[0035] In one embodiment, a mounting groove 411 is provided in the main housing 410, with the groove opening facing upwards and opposite to the conveyor belt 320. The fiber optic head 420 is installed in the mounting groove 411. The main housing 410 has a concave or inclined surface structure on the surface where the groove is opened. The end shape of the conveyor belt 320 is adapted to the concave or inclined surface structure. The end of the conveyor belt 320 is located in the concave or inclined surface structure and forms a gap. The existence of the gap ensures that the high-speed circulating conveyor belt 320 will not directly contact or rub against the fixed main housing 410 during operation. This fundamentally solves the problems of conveyor belt 320 damage, dust generation, or increased running resistance caused by long-term wear, and greatly improves the durability and reliability of the detection device 100.

[0036] Meanwhile, despite the gap, the concave or sloping structure allows the end of the conveyor belt 320 to approach the main housing 410 and the built-in fiber optic head 420 almost directly, providing structural assurance for obtaining a strong detection signal and high sensitivity. This structure provides a semi-sheltered protective space for the fiber optic head 420; the concave or sloping structure effectively blocks liquids, dust, or accidentally dropped small objects from directly impacting the fiber optic head. Furthermore, even if the conveyor belt 320 experiences very slight lateral drift during operation, this structure guides and limits its movement, preventing collisions and ensuring the accuracy of detecting the presence of the PCB board 101.

[0037] In some embodiments, a cover 340 is provided at a certain distance above the conveyor belt 320, covering the bearing surface 330. The cover 340 effectively prevents suspended dust, hair, fine debris, and liquids or oils that may drip from above from falling onto the bearing surface 330 of the conveyor belt 320 or the delicate PCB board 101. This is crucial for keeping the PCB board 101 clean and preventing subsequent soldering or inspection failures due to contamination. The cover 340 isolates the conveyor belt 320 and the PCB board 101 from the external environment, preventing the hands, clothing, or other tools of production line operators from accidentally touching the running conveyor belt 320 and the PCB board 101. This ensures personal safety and prevents accidental interference and interruption of the automated production process. In some specific application scenarios, for example, for thin PCB boards 101, if the airflow above them is unstable during transport, it may exacerbate the slight drift or vibration of the PCB board 101. The presence of the cover 340 forms a stable cavity structure above the conveyor belt 320, which can effectively smooth the airflow and suppress the positional influence of air disturbance on thin workpieces, providing a more stable environment for the fiber optic detection below, thereby improving the accuracy of detecting the presence status of the PCB board 101.

[0038] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A detection device, characterized in that, The device includes a base, a conveying assembly, and an optical fiber sensing assembly. The conveying assembly includes drive wheels and a conveyor belt. The drive wheels are driven to the base, and the conveyor belt is sleeved on multiple drive wheels. The conveyor belt is used to carry and convey PCB boards, and a through slot is formed along the conveying direction. The optical fiber sensing assembly includes a main housing and an optical fiber head. The main housing is disposed on the base, and the optical fiber head is directly opposite the through slot. The optical fiber head is flush with the bearing surface of the conveyor belt to detect the PCB boards on the bearing surface of the conveyor belt.

2. The detection device according to claim 1, characterized in that, The fiber optic head is located at the end of the conveyor belt.

3. The detection device according to claim 2, characterized in that, The conveyor belt has a first end and a second end, and the first end and the second end are respectively provided with an optical fiber head.

4. The detection device according to claim 2, characterized in that, The optical fiber heads located at both ends of the conveyor belt are arranged opposite each other along the conveying direction of the conveyor belt.

5. The detection device according to claim 1, characterized in that, The through slot is located in the middle region of the conveyor belt in the width direction.

6. The detection device according to claim 1, characterized in that, The fiber optic head is located in the through slot.

7. The detection device according to claim 1, characterized in that, The through groove extends along the length of the conveyor belt.

8. The detection device according to claim 1, characterized in that, The depth of the through groove is 0.5 to 0.8 times the thickness of the PCB board.

9. The detection device according to claim 1, characterized in that, The main housing has an installation groove, the opening of which is opposite to the conveyor belt. The optical fiber head is installed in the installation groove. The main housing has a concave or inclined surface structure on the surface where the groove is opened. The end shape of the conveyor belt is adapted to the concave or inclined surface structure. The end of the conveyor belt is located in the concave or inclined surface structure and forms a gap.

10. The detection device according to claim 1, characterized in that, Covering elements are spaced apart above the conveyor belt, and the covering elements cover the bearing surface.

Images