Chopped wave structure and handheld imaging equipment

Abstract

The chopping structure comprises a chopping cylinder, a shielding structure and a driving switching mechanism. At least two twisted slits are formed in the cylinder wall of the chopping cylinder, and the twisted slits are configured to enable an incident conical X-ray beam to form a scanning pencil beam when the chopping cylinder rotates. And a shielding cavity for accommodating the chopping cylinder is arranged in the shielding structure. And the driving switching mechanism is connected to the chopping cylinder and is used for driving the chopping cylinder to rotate and driving the chopping cylinder to move between a first working position in the shielding cavity and a second working position moving out of the shielding cavity. Wherein when the chopping cylinder is in the first working position, the imaging system of the chopping structure is in a back scattering imaging mode; and when the chopping cylinder is in the second working position, the imaging system is in a transmission imaging mode. According to the chopping structure provided by the invention, the chopping cylinder is applied to the handheld imaging equipment, and the mode of the chopping cylinder is switched, so that the imaging mode is quickly switched, additional complex operation is not needed, and integration of back scattering imaging and transmission imaging is realized.

Description

Technical Field

[0001] This invention belongs to the field of radiation imaging detection technology, specifically, it relates to a chopper structure and a handheld imaging device. Background Technology

[0002] X-ray imaging is generally divided into transmission imaging and backscattering imaging. Transmission imaging is based on the linear attenuation law of X-rays as they penetrate matter, following the Lambert-Beer law. When X-rays penetrate an object, photons interact with the matter through the photoelectric effect, Compton scattering, and pair production, causing the X-ray intensity to decay exponentially. Transmission imaging offers high resolution and is excellent for detecting high-density metal parts, making it common in fields requiring fine imaging, such as medicine and industry. Backscattering imaging, on the other hand, utilizes the Compton scattering effect to reconstruct information about the object's surface by receiving large-angle scattered photons. The scattering cross-section is approximately inversely proportional to the square of the atomic number, which makes the backscattered signal of low-Z materials (such as organic materials) 100-1000 times stronger than that of high-Z materials. Therefore, backscattering has high sensitivity for detecting composite materials and explosives, offering unique advantages in fields such as security inspection and archaeology.

[0003] In recent years, to further adapt to the needs of in-situ detection, handheld / portable transmission and backscatter imaging technologies based on X-rays have been developed and innovated. However, in practical detection applications, standalone handheld backscatter imaging devices exhibit the following drawbacks: 1) poor penetration capability, such as less than 12mm of stainless steel penetration at 140kV; even the transmission imaging scheme of handheld backscatter imager + FPD has a maximum penetration of less than 26mm and an image resolution of less than 2 lp / mm; 2) insufficient resolution, such as a spatial resolution of 2mm and a wire resolution of 0.15mm. Portable EOD detection schemes typically use portable X-ray machines + FPD flat panel detectors to achieve transmission imaging of the target. This imaging method is technically mature, with a deep transmission depth, such as penetrating 40mm of stainless steel at 140kV, and clear transmission images with high image resolution such as 3lp / mm. However, the equipment is large, heavy, and has high power (hundreds of watts or thousands of watts), making radiation protection difficult. It is not conducive to imaging setup in narrow spaces and has a large radiation leakage, thus increasing the risk of radiation exposure for on-site personnel and mobile personnel in the area. Recently, some companies have launched handheld transmission imaging devices that differ from dental X-ray machines. These devices have an appearance almost identical to backscatter imaging systems and use the same X-ray source. The difference lies in removing the chopper system and backscatter detector of the original handheld backscatter imaging system, adjusting the field of view (FOV) of the handheld backscatter source, and adding a protective plate with an FOV indicator. However, this device only has transmission imaging capabilities and cannot meet the dual detection requirements of backscatter and transmission imaging, and it is also costly. Summary of the Invention

[0004] In view of the problems existing in the prior art described above, this application provides a chopper structure and a handheld imaging device. It can realize the integrated transmission and backscatter dual-mode imaging.

[0005] To achieve the above and other related objectives, the present invention provides a chopper structure, comprising:

[0006] A chopper has at least two twisted slits on its wall, which are configured to cause the incident cone-shaped X-ray beam to form a scanning pencil beam when the chopper rotates.

[0007] The shielding structure has an internal shielding cavity for accommodating the chopper.

[0008] A drive switching mechanism is connected to the chopper and is used to drive the chopper to rotate and move the chopper between a first working position inside the shielded cavity and a second working position outside the shielded cavity.

[0009] Specifically, when the chopper is in the first working position, the imaging system of the chopper structure is in backscatter imaging mode; when the chopper is in the second working position, the imaging system is in transmission imaging mode.

[0010] Optionally, the drive switching mechanism includes:

[0011] The drive shaft is connected to the chopper.

[0012] A rotary drive unit is connected to one end of the drive shaft;

[0013] The linear drive unit, connected to the drive shaft, is used to drive the chopper to move axially along the drive shaft, so as to switch the chopper between the first working position and the second working position.

[0014] Optionally, the chopper structure further includes at least two bearings disposed at both ends of the chopper cylinder, and at least one bearing disposed on the drive shaft.

[0015] Optionally, the linear drive unit includes a lead screw, a moving part that cooperates with the lead screw, and a drive motor that drives the lead screw to rotate, wherein the moving part is connected to the drive shaft.

[0016] Optionally, the moving part is a disc, and the drive shaft is provided with a drive shaft groove that mates with the disc.

[0017] Optionally, the sidewall of the shielding structure is provided with a chopper assembly port, and a labyrinth structure for absorbing scattered X-rays is formed between the shielding cavity and the outer wall of the chopper in the first working position.

[0018] Optionally, the chopper structure may also include a position sensor for detecting whether the chopper has reached the first working position.

[0019] Optionally, the chopper includes a long twisted slit and a short twisted slit, the axial projections of the long twisted slit and the short twisted slit on the chopper wall having a persistent intersection point.

[0020] Alternatively, the chopper may be made of tungsten, lead, or tungsten steel.

[0021] Another aspect of the present invention provides a handheld imaging device, comprising:

[0022] The detector is positioned at the very front of the handheld imaging device;

[0023] The radiation source is positioned at an interval from the detector;

[0024] The chopper structure includes the chopper structure described above, wherein the chopper structure is disposed on the side of the X-ray source closer to the detector;

[0025] The main unit casing houses the X-ray source and the chopper structure.

[0026] As described above, the chopper structure and handheld imaging device provided by the present invention have at least the following beneficial technical effects:

[0027] The chopper structure of the present invention includes a chopper tube, a shielding structure, and a drive switching mechanism. At least two tortuous slits are formed on the wall of the chopper tube, and these slits are configured to cause the incident conical X-ray beam to form a scanning pencil beam when the chopper tube rotates. The shielding structure has a shielding cavity inside for accommodating the chopper tube. The drive switching mechanism is connected to the chopper tube and is used to drive the chopper tube to rotate and move between a first working position within the shielding cavity and a second working position outside the shielding cavity. When the chopper tube is in the first working position, the imaging system of the chopper structure is in backscatter imaging mode; when the chopper tube is in the second working position, the imaging system is in transmission imaging mode.

[0028] This invention's chopper structure applies a chopper tube to a handheld imaging device, enabling rapid switching of imaging modes by changing the chopper tube's mode without requiring additional complex operations, thus integrating backscatter and transmission imaging. Furthermore, compared to traditional chopper wheel-type structures, the chopper tube structure is more compact and space-efficient, effectively reducing system weight and size, resulting in a more compact and flexible overall system. Additionally, this invention's chopper structure is compatible with existing handheld backscatter imager structures, facilitating technological iteration and market promotion. Attached Figure Description

[0029] Figure 1 The diagram shows a structural schematic of the chopper located in the first working position within the shielding cavity, as provided in an embodiment of the present invention.

[0030] Figure 2The diagram shows a structural schematic of the chopper located in the second working position outside the shielding cavity, as provided in an embodiment of the present invention.

[0031] Figure 3 The diagram shown is a structural schematic of a chopper provided in an embodiment of the present invention.

[0032] Figure Labels

[0033] 1. Chopper; 11. Twisted slit; 2. Shielding structure; 21. Shielding cavity; 22. Chopper assembly port; 3. Drive switching mechanism; 31. Drive shaft; 311. Drive shaft groove; 32. Rotary drive unit; 33. Linear drive unit; 331. Lead screw; 3311. Support rod; 332. Moving part; 333. Drive motor; 4. Bearing; 5. Position sensor. Detailed Implementation

[0034] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand the invention from the content disclosed in this specification.

[0035] This invention also offers other advantages and benefits. Furthermore, the invention can be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the invention.

[0036] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the actual number, shape and size of the components, the shape, quantity, positional relationship and proportion of each component can be arbitrarily changed under the premise of realizing the technical solution of this invention, and the layout of the components may also be more complex.

[0037] Example 1

[0038] This embodiment provides a chopper structure, referring to... Figures 1 to 3 The chopper structure includes a chopper cylinder 1, a shielding structure 2, and a drive switching mechanism 3.

[0039] Reference Figure 3The chopper 1 has at least two tortuous slits 11 on its wall. These slits are configured to form a scanning pencil beam from the incident conical X-ray beam when the chopper 1 rotates. Specifically, as the chopper 1 rotates, the incident X-ray beam can only pass through the periodically overlapping gap area of ​​the two tortuous slits 11, thus being "cut" and shaped into an extremely thin, high-speed pencil beam. This pencil beam formation process is dynamic: as the chopper 1 rotates, the incident X-ray beam can only pass through the periodically overlapping gap area of ​​the two tortuous slits 11, thereby achieving precise control of the X-ray beam. This design not only effectively focuses the X-ray beam but also enables continuous scanning during high-speed rotation. In this embodiment, the chopper 1 is made of tungsten, lead, or tungsten steel. These materials effectively block rays traveling in unintended directions, ensuring that only rays passing through the tortuous slit 11 form an effective beam. This improves the signal-to-noise ratio of the imaging signal and significantly reduces radiation leakage, enhancing system safety. Specifically, the chopper 1 includes a long tortuous slit and a short tortuous slit. The axial projections of the long and short tortuous slits onto the wall of the chopper 1 have a persistent intersection point. As the chopper 1 rotates, this intersection point moves smoothly along the axis of the chopper 1, thereby driving the pencil beam passing through the intersection point to complete a linear scan. This design replaces a complex multi-component scanning system, achieving a compact and reliable mechanical flying-spot generation, which is the key technology for miniaturizing and integrating chopper structures.

[0040] Reference Figure 1 and Figure 2 The working position of the chopper 1 directly determines the detection mode of the imaging system. Specifically, the positional change of the chopper 1 within the shielded cavity 21 enables the imaging system to rapidly switch between backscatter imaging mode and transmission imaging mode. This switching mechanism, based on the mechanical positional change of the chopper 1, is reliable and easy to operate. (Refer to...) Figure 1 When the chopper 1 is precisely moved and positioned within the shielded cavity 21 by the linear drive unit 33, the imaging system of the chopper structure is in backscatter imaging mode. Conversely, referring to... Figure 2 When the chopper 1 is moved out of the shielding cavity 21 and reaches the second working position, the X-rays will be emitted unobstructed in their original cone shape, and the imaging system will be in transmission imaging mode. This mode switching mechanism based on mechanical position reliably meets the dual detection requirements.

[0041] Reference Figure 1 and Figure 2The shielding structure 2 is the core radiation protection unit of the chopper structure, and its interior contains a shielding cavity 21 for accommodating the chopper tube 1. Preferably, the shape and size of the shielding cavity 21 match the external shape of the chopper tube 1. A chopper tube assembly port 22 is provided on the side wall of the shielding structure 2, serving as a channel for the chopper tube 1 to move into or out of the shielding cavity 21. A labyrinth structure for absorbing scattered X-rays is formed between the shielding cavity 21 and the outer wall of the chopper tube 1 in its first working position. Specifically, when the chopper tube 1 is pushed in and fixed in the first working position, the outer wall of the chopper tube 1 and the inner wall of the shielding cavity 21 are not tightly fitted, but rather a deliberately formed tortuous, non-straight-through gap channel, i.e., a labyrinth structure. The labyrinth structure can effectively capture and absorb unwanted X-rays, attenuating their energy through multiple collisions, thereby significantly reducing radiation leakage and ensuring the safety and compliance of the operation process.

[0042] Reference Figure 1 and Figure 2 The drive switching mechanism 3 is a core motion component connected to the chopper 1, and it has a dual drive function. Specifically, the drive switching mechanism 3 is connected to the chopper 1 and is used to drive the chopper 1 to rotate and drive the chopper 1 to move between a first working position inside the shielding cavity 21 and a second working position outside the shielding cavity 21.

[0043] Reference Figure 1 and Figure 2 The drive switching mechanism 3 is a precision transmission unit that controls the chopper 1 to complete two core actions—rotational scanning and axial movement switching. Specifically, in this embodiment, the drive switching mechanism 3 includes a drive shaft 31, a rotary drive unit 32, and a linear drive unit 33. The drive shaft 31 is the core component for power transmission, connected to the chopper 1, and precisely transmits motion to the chopper 1 itself.

[0044] Reference Figure 1 and Figure 2The rotary drive unit 32 is connected to one end of the drive shaft 31, providing power to drive the drive shaft 31 and its fixed chopper 1 to rotate at high speed and smoothly around the axis. In this example, the rotary drive unit 32 and the drive shaft 31 are fastened together to ensure close cooperation during power transmission, achieving efficient and stable rotational motion. This fastening connection can be achieved through threaded connections, keyed connections, or other mechanical fixing methods to ensure that the power of the rotary drive unit 32 is accurately transmitted to the drive shaft 31, thereby driving the chopper 1 to rotate at high speed. However, this connection method is not limited to a fastening connection; various other drive methods can be used to achieve the same function. For example, gear drive is a common alternative. In this case, the rotary drive unit 32 can be connected to the drive shaft 31 through one or more gears. The advantage of gear drive is that it can precisely control the transmission ratio, thereby achieving precise adjustment of the rotational speed of the chopper 1. Chain drive is another feasible alternative. In this design, the rotary drive unit 32 is connected to the drive shaft 31 through a chain.

[0045] A linear drive unit 33 is connected to a drive shaft 31 and is used to drive the chopper 1 to move axially along the drive shaft 31, thereby switching the chopper 1 between a first working position and a second working position. The linear drive unit 33 includes a lead screw 331, a moving component 332 that engages with the lead screw 331, and a drive motor 333 that drives the lead screw 331 to rotate. The moving component 332 is connected to the drive shaft 31. Specifically, the drive motor 333 provides power to rotate the lead screw 331. The moving component 332, which engages with the lead screw 331 via a thread, subsequently generates a precise axial displacement. The moving component 332 is fixedly connected to the drive shaft 31, thereby reliably transmitting linear motion to the chopper 1, enabling the chopper 1 to reciprocate between a first working position within the shielded cavity 21 and a second working position completely removed. As a preferred and reliable embodiment, the moving component 332 is designed in a disc shape. To this end, a corresponding drive shaft groove 311 is provided on the drive shaft 31, and the disc can be embedded in the drive shaft groove 311 to achieve power coupling and connection. This combination drive method of lead screw and disc not only ensures the linear accuracy of movement and the reliability of repeatability, but also makes the entire switching process smooth and controllable. It is the key mechanical guarantee for realizing the chopper structure to switch quickly and accurately between backscattering and transmission modes.

[0046] Reference Figure 1 and Figure 2The chopper structure also includes at least two bearings 4, symmetrically arranged at both ends of the chopper cylinder 1, providing stable support for the core rotating components. At least one bearing 4 is directly mounted on the drive shaft 31, bearing the main radial load. The inner ring of the bearing 4 is tightly fitted to the drive shaft 31, together forming a low-friction, high-rigidity rotary system. This design ensures that the chopper cylinder 1 maintains axial stability and smooth movement during high-speed rotation, thus laying a reliable mechanical foundation for generating uniform and accurate scanning points and effectively extending the service life of key moving parts.

[0047] Reference Figure 1 and Figure 2 The chopper structure also includes a position sensor 5, used to detect whether the chopper 1 has reached the first working position, so as to achieve accurate detection of the working status of the chopper 1 and automatic judgment of the system mode. When the position sensor 5 detects the chopper 1, it means that the chopper 1 has reached the first working position, and the imaging system of the chopper structure is in backscatter imaging mode; when the position sensor 5 does not detect the chopper 1, it means that the chopper 1 has reached the second working position, and the imaging system of the chopper structure is in transmission imaging mode. Specifically, the position sensor 5 (usually using non-contact principles such as optical, magnetic induction or proximity switch) is fixedly installed on the shielded cavity 21. Its core function is to detect whether the chopper 1 has accurately reached and stopped in the first working position (i.e., the backscatter imaging preparation state fully embedded in the shielded cavity 1). Preferably, when the position sensor 5 detects that the chopper 1 has entered its effective sensing range, it will generate a clear electrical signal. After receiving this signal, the control system of the handheld imaging device determines that the chopper 1 is in place, and then automatically starts the rotation drive unit 32 and configures the entire system in backscatter imaging mode, at which time the device can perform surface scanning imaging. Conversely, if the rotary drive unit 32 is shut off first, and the chopper 1 is completely moved out of the shielding cavity 21 under the action of the linear drive unit 33 and reaches the second working position, the position sensor 5 will lose its signal because the detected target is far away. Based on this, the control system determines that the chopper 1 has exited and switches the system to transmission imaging mode, allowing the cone beam to directly penetrate the object. This sensor-based closed-loop detection mechanism greatly improves the reliability and safety of mode switching, effectively preventing imaging function abnormalities or radiation mis-exposure risks caused by mechanical positioning errors. It is an important component in realizing the intelligence and ease of operation of the chopper structure.

[0048] Reference Figures 1 to 3This embodiment of the chopper structure applies a chopper tube 1 to a handheld imaging device. By switching the mode of the chopper tube 1, the imaging mode can be quickly switched without additional complex operations, achieving integrated backscatter imaging and transmission imaging. Furthermore, compared to traditional chopper wheel-type chopper structures, the chopper tube 1 has a compact structure and high space utilization, effectively reducing system weight and size, making the entire system more compact and flexible. In addition, the chopper structure of this invention is compatible with existing handheld backscatter imager structures, facilitating technological iteration and market promotion.

[0049] Example 2

[0050] This embodiment provides a handheld imaging device, including a detector, an X-ray source, a chopping structure, and a main unit housing. The detector is located at the front end of the handheld imaging device. The X-ray source and the detector are spaced apart. The chopping structure includes the chopping structure described in Embodiment 1, and is located on the side of the X-ray source closer to the detector. The main unit housing accommodates the X-ray source and the chopping structure.

[0051] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A chopper structure, characterized in that, include: A chopper, wherein at least two tortuous slits are provided on the wall of the chopper, the tortuous slits being configured to cause the incident cone-shaped X-ray beam to form a scanning pencil beam when the chopper is rotated; The shielding structure has an internal shielding cavity for accommodating the chopper. A drive switching mechanism is connected to the chopper and is used to drive the chopper to rotate and drive the chopper to move between a first working position inside the shielding cavity and a second working position outside the shielding cavity. When the chopper is in the first working position, the imaging system of the chopper structure is in backscatter imaging mode; when the chopper is in the second working position, the imaging system is in transmission imaging mode.

2. The chopper structure according to claim 1, characterized in that, The drive switching mechanism includes: The drive shaft is connected to the chopper. A rotary drive unit is connected to one end of the drive shaft; A linear drive unit, connected to the drive shaft, is used to drive the chopper to move axially along the drive shaft, so as to switch the chopper between the first working position and the second working position.

3. The chopper structure according to claim 2, characterized in that, Also includes: At least two bearings are disposed at both ends of the chopper, and at least one bearing is disposed on the drive shaft.

4. The chopper structure according to claim 2, characterized in that, The linear drive unit includes a lead screw, a moving part that cooperates with the lead screw, and a drive motor that drives the lead screw to rotate. The moving part is connected to the drive shaft.

5. The chopper structure according to claim 4, characterized in that, The moving part is a disc, and the drive shaft is provided with a drive shaft groove that cooperates with the disc.

6. The chopper structure according to claim 1, characterized in that, The shielding structure has a chopper assembly port on its side wall, and a labyrinth structure for absorbing scattered X-rays is formed between the shielding cavity and the outer wall of the chopper in the first working position.

7. The chopper structure according to claim 1, characterized in that, Also includes: A position sensor is used to detect whether the chopper has reached the first working position.

8. The chopper structure according to claim 1, characterized in that, The chopper includes a long twisted slit and a short twisted slit, the axial projections of the long twisted slit and the short twisted slit on the chopper wall having a continuous intersection point.

9. The chopper structure according to claim 1, characterized in that, The chopper is made of tungsten, lead, or tungsten steel.

10. A handheld imaging device, characterized in that, include: The detector is located at the very front of the handheld imaging device; The radiation source is positioned at an interval from the detector; A chopper structure, including the chopper structure according to any one of claims 1 to 9, wherein the chopper structure is disposed on the side of the X-ray source close to the detector; The main unit housing is used to house the X-ray source and the chopper structure.

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