Installation method of capacitive coupling slip ring

Abstract

The present invention relates to a method for installing a capacitively coupled slip ring, belonging to the technical field of X-ray computed tomography (CT) imaging technology. This method solves the problem that existing slip rings increase the communication rate of the entire system by increasing the width of the rotating disk, resulting in increased equipment size and high costs. The method for installing a capacitively coupled slip ring includes the following steps: Step 1: Mounting the rotating disk on the CT gantry; Step 2: Mounting a receiving unit on the outer surface of the rotating disk; Step 3: Mounting a receiving unit on the inner surface of the rotating disk. The present invention enables multi-channel data transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of X-ray computed tomography imaging technology (abbreviated as "CT technology"), and in particular to a method for installing a capacitive coupling slip ring. Background Art

[0002] X-ray computed tomography imaging technology (abbreviated as "CT technology") is highly valued and widely used in the field of security inspection due to its unique advantages.

[0003] Capacitive coupling slip ring is one of the key components of CT, used for power and data transmission between the rotor end and the stator end of CT.

[0004] At present, the commonly used non-contact conductive slip rings and the data transmission methods between rotating bodies mainly include wireless capacitive coupling transmission and optical transmission.

[0005] Capacitively coupled slip rings transmit signals through capacitive coupling between a flexible antenna wrapped around the outer edge of a rotating disk and a receiving antenna at a fixed end. Compared to optical transmission slip rings, capacitively coupled slip rings offer advantages such as smaller size, lighter weight, smaller footprint, and lower cost. However, they also generate electromagnetic radiation and are susceptible to electromagnetic interference. Variations in the distance between the moving and stationary coils can affect data acquisition, making it difficult to meet data transmission speed requirements.

[0006] Both the transmitting and receiving antennas of capacitively coupled slip rings are constructed on printed circuit boards. Due to the inherent properties of the printed circuit board materials and the plug-in connection method, signal integrity issues may deteriorate as the transmission frequency increases. Combined with the principle of wireless capacitive coupling transmission, the maximum signal transmission rate is limited, preventing unlimited increases. Currently, the maximum signal transmission rate for a single-channel transmitting antenna on the market is 10 Gbps. As the amount of transmitted data increases, higher requirements are placed on transmission speed and bit error rate.

[0007] Existing technologies typically increase the width of the rotating disk to increase the number of communication channels while maintaining a 10Gbps transmission rate per channel. However, increasing the width of the rotating disk increases the size of the device and increases costs. Summary of the Invention

[0008] In view of the above analysis, the present invention aims to provide a method for installing a capacitively coupled slip ring to solve the problem that the existing slip ring increases the communication rate of the entire system by increasing the width of the rotating disk, resulting in an increase in equipment size and high cost.

[0009] The purpose of the present invention is mainly achieved through the following technical solutions:

[0010] The present invention provides a method for installing a capacitive coupling slip ring, comprising the following steps:

[0011] Step 1: Install the rotating disk on the CT gantry;

[0012] Step 2: Install the receiving unit on the outer surface of the rotating disk;

[0013] Step 3: Install the receiving unit on the inner surface of the rotating disk.

[0014] Based on a further improvement of the above installation method, step 2 includes installing the receiving unit on the outer surface of the rotating disk on the CT gantry.

[0015] Based on a further improvement of the above installation method, step 3 includes installing the receiving unit on the inner surface of the rotating disk on the CT gantry.

[0016] Based on a further improvement of the above installation method, step 2 specifically includes fixing the receiving end data processing module of the receiving unit on the CT frame.

[0017] Based on a further improvement of the above installation method, the receiving antenna is aligned with the transmitting antenna, and a certain distance is spaced between them.

[0018] Based on further improvement of the above installation method, the receiving antenna and the transmitting antenna are spaced 1.5-5 mm apart.

[0019] Based on the further improvement of the above installation method, the receiving antenna and the transmitting antenna are spaced 3 mm apart.

[0020] Based on a further improvement of the above installation method, step 3 specifically includes: fixing the receiving end data processing module of the receiving unit on the CT frame.

[0021] Based on a further improvement of the above installation method, the receiving antenna is aligned with the transmitting antenna, and the interval between them is 1.5-5 mm.

[0022] Based on the further improvement of the above installation method, the receiving antenna and the transmitting antenna are spaced 2 mm apart.

[0023] Based on the further improvement of the above-mentioned installation method, the capacitively coupled slip ring includes a rotating disk, a transmitting unit and a receiving unit, and the transmitting unit includes a transmitting antenna and a transmitting end data processing unit; the rotating disk is annular with a hollow interior, and the outer surface and the inner surface of the rotating disk are both provided with circumferentially arranged grooves, the shape of the grooves matches the shape of the transmitting antenna, and the transmitting antenna is placed in the grooves.

[0024] Based on the further improvement of the above-mentioned capacitive coupling slip ring, the receiving unit includes a receiving end data processing unit and a receiving antenna.

[0025] Based on the further improvement of the above-mentioned capacitive coupling slip ring, the number of the grooves on the outer surface of the rotating disk is at least one.

[0026] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0027] (1) In the prior art, the transmitting antenna is arranged on the outer surface of the rotating disk. In order to improve the communication rate of the entire system, the prior art usually increases the width of the rotating disk. While ensuring a 10Gbps transmission rate for each channel, the number of communication channels is increased to improve the communication rate of the entire system. However, increasing the width of the rotating disk will increase the size of the equipment and increase the cost. The present invention arranges transmitting antennas on both the inner and outer surfaces of the rotating disk. This can increase the number of communication channels without increasing the width of the rotating disk, thereby improving the communication rate of the entire system.

[0028] (2) In order to prevent signal interference between different transmitting antennas on the same side, the spacing between different transmitting antennas on the same side in the prior art is not less than three times the width W of the transmitting antenna (i.e., 3W). The present invention adopts a solution of embedded receiving antenna, i.e., the depth of the groove on the rotating disk for placing the transmitting antenna is greater than the thickness of the transmitting antenna. After the transmitting antenna is placed in the groove, there is a height difference between the upper surface of the transmitting antenna and the outer surface of the rotating disk. The above arrangement can effectively reduce the radiation field of the transmitted signal. Therefore, even when the spacing between different groups of transmitting antennas is reduced, the interference between different transceiver modules can be reduced, and the utilization rate of the electric slip ring disk can be effectively improved while ensuring normal signal communication.

[0029] (3) In the prior art, PCB circuit boards are usually used to make capacitive coupling antennas. Since the material of PCB boards is relatively brittle, the capacitive coupling antennas made of PCB boards are easily broken during the bending process, and the length of the capacitive coupling antennas made of PCB boards is limited, generally not exceeding 2.5m. Therefore, when two capacitive coupling antennas made of PCB boards are wrapped around a rotating disk, due to the limited length, there is a distance between the signal output end and the signal input end of the two antennas, thereby reducing the signal transmission efficiency. Since they are easy to break during the bending process, the two antennas are likely to lose the information transmission function during use. The present invention uses polyethylene or tetrafluoroethylene as a base material to make a capacitive coupling antenna, so that the capacitive coupling antenna has sufficient flexibility and the generated antenna length can reach more than 2m, and it can ensure that the antenna will not break during the bending process, thereby improving the signal transmission efficiency.

[0030] (4) The CT detection device of the present invention includes a rotating disk. The capacitively coupled antenna (transmitting antenna) is typically wound around the rotating disk and rotates 360 degrees along with the rotating disk. Therefore, the transmitting antenna is connected to the transmitting communication module via a connector to facilitate the capacitively coupled antenna's 360-degree rotation along with the rotating disk.

[0031] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages may become obvious from the description or be understood through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0033] Figure 1 This is a schematic structural diagram of a capacitively coupled slip ring according to an embodiment of the present invention;

[0034] Figure 2 A partial cross-sectional view of a rotating disk according to an embodiment of the present invention;

[0035] Figure 3 A diagram showing the relationship between the spacing between adjacent transmitting antennas and antenna width in the prior art;

[0036] Figure 4 A partial cross-sectional view of a rotating disk with an embedded transmitting antenna according to an embodiment of the present invention;

[0037] Figure 5 A schematic structural diagram of a CT detection device provided in an embodiment of the present invention;

[0038] Figure 6 A schematic structural diagram of a two-layer circuit board provided in an embodiment of the present invention;

[0039] Figure 7 This is the CT block diagram.

[0040] Reference numerals:

[0041] 1-rotating disk; 2-transmitting antenna; 3-first groove; 4-second groove; 5-receiving unit; 6-plug-in; 7-first metal copper foil; 8-substrate; 9-second metal copper foil; 10-ray source; 11-CT rack; 30-CT detector; 40-detected object; 50-conveyor belt; 60-conveyor belt motor; 70-motion control computer; 80-slip ring motor; 90-data processing computer. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0043] Example 1

[0044] A specific embodiment of the present invention discloses a capacitive coupling slip ring, which includes a rotating disk 1, a transmitting unit and a receiving unit.

[0045] like Figure 1 As shown, the transmitting unit includes a transmitting antenna 2 and a transmitting data processing unit. The transmitting data processing unit includes a transmitting circuit board and a data cable. The transmitting antenna 2 and the data cable are both connected to the transmitting circuit board. For example, the transmitting antenna 2 and the transmitting circuit board are connected via a connector. The transmitting circuit board is fixed to the rotating disk.

[0046] The transmitting antenna used in the present invention is in a flat shape, or in a strip shape.

[0047] The rotating disk is a large-aperture ring with a hollow interior. A first groove 3 is provided on its outer surface in a circumferential direction. The shape of the first groove 3 matches the shape of the transmitting antenna 2 , and the transmitting antenna 2 is placed in the first groove 3 .

[0048] It should be noted that, depending on the diameter of the rotating disk, the transmitting antenna located within first groove 3 can be a single antenna or multiple antennas forming a complete circle. Specifically, the circuit board has two pathways, with adjacent antennas connected to each pathway. The receiving unit includes a receiving circuit board and a data cable, which is connected to the receiving circuit board.

[0049] The receiving unit 5 includes two parts: a receiving end data processing unit and a receiving antenna. The two parts can be integrated into a printed circuit or connected in a plug-in form.

[0050] The receiving unit includes a first receiving unit and a second receiving unit. The first receiving unit is arranged near the outer surface of the rotating disk and is 1.5-5 mm away from the transmitting antenna in the first groove.

[0051] In a possible embodiment, the inner surface of the rotating disk 1 is also provided with a circumferentially arranged groove (second groove 4), such as Figure 2 The shape of the second groove 4 matches the shape of the transmitting antenna, and the transmitting antenna is placed in the second groove.

[0052] It should be noted that the transmitting antenna 2 in this embodiment is fixed in the groove. For example, the transmitting antenna can be fixed in the groove by gluing.

[0053] The second receiving unit is arranged near the inner surface of the rotating disk and is 1.5-5 mm away from the transmitting antenna in the second groove.

[0054] It should be noted that the number of the first groove 3 and the second groove 4 is at least one. For example, 1 first groove and 1 second groove; or 1 first groove and 2 second grooves; 2 first grooves and 1 second groove; or 2 first grooves and 2 second grooves, such as Figure 2 The position of the second groove may correspond to the position of the first groove, or may not correspond to the position of the first groove.

[0055] The transmission unit and the receiving unit are connected through the principle of capacitive coupling, that is, the electric field coupling between the transmitting and receiving antennas. If the distance between different groups of transmitting and receiving antennas is too close, crosstalk between different transmitting and receiving modules will occur, resulting in abnormal communication. Therefore, in order to prevent signal interference between different transmitting antennas on the same side, the spacing D between different transmitting antennas on the same side in the prior art is not less than three times the width W of the transmitting antenna (i.e. 3W), and the dielectric thickness H between the transmitting antennas on different sides is not less than three times the width of the transmitting antenna, such as Figure 3 As shown (for ease of expression, the transmitting antenna is illustrated as protruding from the outer surface of the rotating disk).

[0056] However, due to space limitations, it is impossible to infinitely increase the distance between different transceiver modules. Therefore, in one possible embodiment of the present invention, a solution of embedding the receiving antenna is adopted, that is, the depth of the groove is not the same as the thickness of the transmitting antenna, but the depth of the groove is greater than the thickness of the transmitting antenna, such as Figure 4 Thus, after the transmitting antenna is placed in the groove, there is a height difference between the upper surface of the transmitting antenna and the outer surface of the rotating disk, that is, the upper surface of the transmitting antenna is not flush with the outer surface of the rotating disk, but lower than the outer surface of the rotating disk.

[0057] Specifically, the antenna is 2mm thick, and the groove is 3mm deep. This places the surface of the transmitting antenna 1mm from the side of the rotating disk. This arrangement effectively reduces the radiation field of the transmitted signal. Therefore, even when the spacing between different groups of transmitting antennas is reduced, interference between different transceiver modules is reduced, effectively improving the utilization rate of the electric slip ring disk while ensuring normal signal communication.

[0058] Through experimental research, the present invention has found that with the above-mentioned embedded structural setting, the spacing between the transmitting antennas on the same side does not need to reach 3 times the width of the transmitting antenna (i.e. 3W), but only needs to be 1-2 times the width of the transmitting antenna to ensure normal communication.

[0059] Example 2

[0060] Another specific embodiment of the present invention discloses a CT detection device, wherein the capacitive coupling slip ring is one of the key components of the CT and is used for power and data transmission between the rotor end and the stator end of the CT.

[0061] With the advancement of CT technology, the amount of data collected by detectors is increasing day by day. The required data transmission bandwidth can be estimated by Formula 6, which gives the following relationship between the number of CT slices and data bandwidth. Formula 6:

[0062]

[0063] Where S is the data transmission bandwidth; P is the number of multi-slice spiral CT DAS channels; n is the number of single-slice spiral CT detectors; m is the number of single-sample data bits of each detector; v is the slip ring rotation speed; and f is the sampling frequency.

[0064] The corresponding relationship between the number of CT layers and data bandwidth is as follows:

[0065]

[0066] Based on the relationship between CT slice number and data bandwidth, the data transmission bandwidth for a 16-slice spiral CT must reach 1.25 Gbps, the data transmission bandwidth for a 64-slice spiral CT must reach 5 Gbps, the data transmission bandwidth for a 256-slice spiral CT must reach 20 Gbps, and the data bandwidth requirement for a 640-slice spiral CT has reached 50 Gbps. Single-channel capacitive coupling transmission is no longer able to meet these requirements, so the present invention provides a multi-channel transmission solution.

[0067] The CT detection device of this embodiment includes a ray source 10, a rotating disk 1 and a CT detector 30, a conveyor belt 50, a data processing unit 90, a conveyor belt motor 60, a slip ring motor 80 and a motion control computer 70. Figure 5 As shown, a radiation source 10 is fixed to a rotating disk 1. A conveyor belt 50 passes through the large hollow aperture of the rotating disk 1. The object to be inspected 40 is placed on the conveyor belt 50. The CT detector 30 is also fixed to the rotating disk 1. The conveyor belt 50 is connected to a conveyor belt motor 60. The rotating disk 1 is connected to a slip ring motor 80. Both the conveyor belt motor 60 and the slip ring motor 80 are connected to a motion control computer 70. The CT detector 30 is connected to a data processing unit 90.

[0068] The specific working method is that when the object 40 is inspected, the rotating disk 1 rotates, driving the radiation source 10 and the CT detector 30 to rotate 360 ​​degrees, thereby obtaining images of the object 40 from multiple angles. The transmitting antenna wrapped circumferentially along the outer and inner surfaces of the rotating disk 1 is used to transmit the images obtained by the CT detector 30 to the data processing unit 90.

[0069] Example 3

[0070] Existing transmitting antennas are typically capacitively coupled antennas, typically made from printed circuit boards (PCBs). PCBs are made from an insulating substrate, cut to size, with at least one conductive pattern attached and holes (such as component holes, fastening holes, and metallized holes) arranged throughout. They replace the chassis used to house electronic components and facilitate interconnection between them. Because they are manufactured using electronic printing techniques, they are called "printed" circuit boards. Current PCBs primarily consist of circuitry and graphics, a dielectric layer, holes, solder mask ink, silk screen printing, and surface treatment.

[0071] The advantages of capacitively coupled antennas made from PCBs are: The repeatability and consistency of the PCB pattern significantly reduces wiring and assembly errors, saving time in antenna maintenance, commissioning, and inspection. The standardized design, compact size, and light weight make the antennas interchangeable, convenient, precise, and compact.

[0072] The disadvantage of capacitive coupling antennas made of PCB boards is that they are limited by high costs and long cycles for ultra-long circuit boards with flexibility requirements, and may even be impossible to produce due to process limitations.

[0073] This embodiment provides a capacitive coupling antenna for CT detection, such as Figure 6 As shown, it includes: a plug-in 6, a first metal copper foil 7, a substrate 8 and a second metal copper foil 9. Among them, the first metal copper foil 7 is composed of an upper copper foil trace and a lower copper foil trace, and the upper copper foil trace and the lower copper foil trace are differential lines. The plug-in 6, the upper copper foil trace and the lower copper foil trace are arranged on one side of the substrate 8. On the other side of the substrate 8, a second metal copper foil 9 is arranged, and the second metal copper foil 9 also includes a plug-in 6, an upper copper foil trace and a lower copper foil trace, and the upper copper foil trace and the lower copper foil trace are differential lines. Among them, the material of the substrate is polyethylene or polytetrafluoroethylene to ensure that the length of the circuit board can be greater than 2m. In this way, the two capacitively coupled antennas installed on the rotating disk can realize mutual contact between the signal output end and the signal input end to reduce the attenuation of the signal during the transmission process. At the same time, the flexibility of polyethylene and polytetrafluoroethylene can ensure that the capacitively coupled antenna of the present invention is not easy to break when bent, further improving the signal transmission efficiency.

[0074] In the embodiment of the present invention, one side of the plug-in 6 is connected to the communication module, and the other side is connected to the upper and lower copper foil traces.

[0075] In an embodiment of the present invention, the process parameters of the circuit include: the thickness of the substrate, the thickness of the upper copper foil trace, the copper foil width of the upper copper foil trace, the thickness of the lower copper foil trace, and the copper foil width of the lower copper foil trace.

[0076] Specifically, the thickness of the substrate is 0.7 mm to 1.0 mm; the dielectric constant of the substrate is 2.2 to 2.8:

[0077] The thickness of the upper copper foil trace is: 0.1mm-0.2mm; the width of the upper copper foil trace is: 4mm-7mm.

[0078] The thickness of the lower copper foil trace is: 0.1mm-0.2mm; the width of the lower copper foil trace is: 3cm-5cm.

[0079] The above parameters are determined based on the substrate selected. Qualitatively, polyethylene (PE) is a thermoplastic resin made by polymerizing ethylene and is a typical soft yet tough polymer. PE has a high volume resistivity, a low dielectric constant and dielectric loss factor, and is virtually unaffected by frequency.

[0080] PTFE has excellent chemical stability, corrosion resistance, sealing properties, high lubricity and non-stick properties, electrical insulation, and good aging resistance. PTFE is heat-resistant, with an operating temperature of up to 250°C. It is also low-temperature resistant and has excellent mechanical toughness at low temperatures, maintaining an elongation of 5% even at temperatures down to -196°C.

[0081] The present invention uses polyethylene and / or polytetrafluoroethylene as a matrix, which can increase the flexibility of the circuit board, greatly increase the length of the circuit board, and make it less likely to break in a wound state.

[0082] Based on the impedance matching properties of dielectric thickness, conductor width (the width of the upper and lower copper foil traces), and metal thickness (i.e., the thickness of the upper and lower copper foil traces), this paper designs impedance matching for flexible circuits using polyethylene and / or polytetrafluoroethylene as the substrate. The characteristic impedance of a single conductor in a stripline is calculated as shown in Equation 1, and the differential impedance is calculated as shown in Equation 2.

[0083] Formula 1:

[0084] Formula 2:

[0085] Z0 is the characteristic impedance (in ohms), H is the thickness of the medium between the signal line and the plane (in mils), W is the line width (in mils), T Cu Indicates the metal thickness (in mil), ε r Represents the dielectric constant. Z Diff is the differential impedance (in ohms), S is the edge spacing of the trace (in mils), and H is the total dielectric thickness between the planes (in mils).

[0086] As a signal propagates along a transmission line, each step along its path presents a corresponding instantaneous impedance. Different transmission lines have different impedances, so as a signal travels from one line to another, the instantaneous impedance it encounters changes. This causes part of the signal to be reflected, while another part becomes distorted and continues to propagate. The greater the impedance difference, the greater the amount of reflected signal. Impedance fluctuations significantly impact the distortion of the transmitted signal, directly causing degradation of the rising edge of the received signal. To achieve optimal signal quality, the present invention utilizes antennas 2 meters or longer to avoid signal distortion caused by varying instantaneous impedances.

[0087] In DC, the current is evenly distributed in the signal conductor, and the resistance is as shown in Formula 3:

[0088] Formula 3:

[0089] R represents the resistance of the transmission line (in Ω), ρ represents the bulk resistivity of the wire (in Ω·in), Len represents the line length (in), w represents the line width (in), and t represents the thickness of the wire (in).

[0090] At high frequencies, the cross-sectional thickness of the copper conductor through which the current flows is approximately equal to the skin depth δ, as shown in Equation 4:

[0091] Formula 4:

[0092] Where δ represents the skin depth (in μm) and f represents the frequency of the sine wave (in GHz). Due to the skin effect, if the current flows only through the lower half of the wire, the resistance of the wire is approximately as shown in Equation 5:

[0093] Formula 5:

[0094] Where R is the line resistance (in Ω), ρ is the bulk resistivity of the wire (in Ω·in), Len is the line length (in), w is the line width (in), and δ is the skin depth (in).

[0095] From this, we can see that the equivalent resistance of a transmission line increases with the frequency of the transmitted signal, which means that signal loss increases with increasing frequency. Therefore, designing accurate impedance can effectively reduce the attenuation of the transmission medium to the signal.

[0096] The present invention selects polyethylene and / or polytetrafluoroethylene as the substrate of the circuit board and optimizes the capacitive coupling antenna made of the circuit board from two aspects of material performance and connection mode, thereby ensuring image stability and clarity.

[0097] Once the CT scanning device stops scanning, the image of the inspected object 40 will inevitably be interrupted. This application proposes an image stitching method, combining the images of the inspected object 40 before and after the scan is stopped to avoid image interruptions. It should be noted that the capacitive coupling antenna of the present invention can ensure image stability and clarity, providing a technical foundation for this method.

[0098] Specifically, the CT detection device also includes an encoder. The encoder is mounted on the transmission belt and moves with the belt. The encoder is used to collect movement data of the transmission belt and transmit the corresponding relationship to the data processing unit. The movement data includes the movement speed and movement time of the transmission belt.

[0099] The data processing unit is used to determine whether the transmission belt is in a stopped state according to a stop command input from the outside; and to splice the images of the object being inspected before and after the stop according to the X-ray signal transmitted by the capacitive coupling antenna, the movement data and the preset rewind time.

[0100] Furthermore, the CT detector 30 collects X-ray signals corresponding to the first image of the object to be inspected, and transmits the X-ray signal image corresponding to the first image to the data processing unit 90 via the capacitive coupling antenna. The data processing unit 90 determines the first image based on the corresponding X-ray signal. The encoder collects movement data of the transmission belt and transmits the movement data to the data processing unit 90. The movement data includes: the movement speed and movement time of the transmission belt. The data processing unit 90 determines whether the object to be inspected 40 has stopped moving based on a stop command input from the outside. When it is determined that the object to be inspected 40 has stopped moving, the data processing unit 90 determines whether the object to be inspected 40 exists within the preset detection range based on the first image.

[0101] When an object 40 is within the preset detection range, the data processing unit 90 controls the transmission belt via an encoder to first rewind the transmission belt, causing the object 40 to leave the preset detection area. The data processing unit 90 then controls the object 40 to reenter the preset detection area and acquires a second image of the object 40 using the CT detector 30 and the capacitive coupling antenna. Finally, the data processing unit 90 stitches the first and second images together to obtain a complete image of the object 40.

[0102] When there is no detected object 40 within the preset detection range, the data processing unit 90 controls the transmission belt to move in a direction close to the radiation source 10 through the encoder.

[0103] Example 4

[0104] An embodiment of the present invention provides a method for manufacturing a capacitively coupled antenna, which is used to prepare the transmitting antenna of Example 1, and includes the following steps:

[0105] Step 1: Substrate selection.

[0106] In the embodiment of the present invention, polyethylene and / or polytetrafluoroethylene are used as the base material.

[0107] Step 2: Determine the thickness and width of the upper copper foil trace, the thickness and width of the lower copper foil trace, and the substrate thickness based on the impedance matching of the flexible circuit.

[0108] Step 3: Attach the upper copper foil trace and the lower copper foil trace to the substrate to obtain a circuit board.

[0109] Step 4: Apply insulating film to the top and bottom surfaces of the circuit board to obtain a capacitively coupled antenna.

[0110] The technical solution of the present application is described in detail below with reference to examples. The circuit board of the present invention is a flexible circuit board, which is a two-layer flexible circuit board with a length * width * height of 2000mm * 30mm * 1mm. The design is applied to the field of communications and is an antenna for transmitting signals. The antenna needs to transmit a signal at a rate of 2.5GBbps, a required length of 2 meters, and needs to be bent at a certain angle to cooperate with the equipment. The flexible circuit board traces are a pair of differential lines with a differential impedance of 85 ohms. The top trace is 6mm wide and 0.1mm thick copper foil. The spacing between the two traces is 1mm. The middle substrate is polyethylene with a thickness of 0.8mm. The bottom layer is copper foil with a width of 3cm and a thickness of 0.1mm.

[0111] Step 1: Select polyethylene as the base material.

[0112] Polyethylene (PE) is a thermoplastic resin made by polymerizing ethylene. It is a typical soft and tough polymer. PE has a high volume resistivity, a low dielectric constant and dielectric loss factor, and is almost unaffected by frequency.

[0113] Step 2: Determine the parameters.

[0114] When choosing materials, not only impedance but also convenience of material selection should be considered. Considering the difficulty of production and processing and material procurement factors, 3M Industrial Tape 9508W was selected. This industrial tape is a double-sided tape that can easily stick to signal transmission lines. The foam density of this industrial tape is relatively high, 90kg / m 3 , with a thickness of 0.8mm. The copper foil conductor that transmits signals is 6mm wide and 0.1mm thick.

[0115] Step 3: Assembly of the antenna.

[0116] The copper foil is precisely bonded to the industrial tape used as the base material to create the desired signal transmission line. Insulation film is then applied to the top and bottom of the circuit.

[0117] Step 4, test.

[0118] A network analyzer was used to test the characteristic impedance and S-parameters of the fabricated flexible circuit to confirm its quality. The test showed that the flexible circuit (2m in length) could transmit high-frequency signals at a rate of 2.5Gbps, with a measured signal attenuation of less than 3dB.

[0119] Currently, the mature manufacturing process for high-frequency printed circuit boards (PCBs) can reach lengths of up to 1.2 meters and lacks flexibility. The cost of producing a 1.2-meter PCB is approximately 2,000 yuan. Producing longer, high-speed PCBs requires collaborating with manufacturers to develop new production lines and processes, which carries the disadvantages of high costs and unpredictable quality.

[0120] The high-speed flexible circuit design method proposed in this invention only requires ensuring the precise attachment of the transmission conductors. The flexible circuit board length can be measured and cut using a ruler, allowing for customized design based on product requirements. The dielectric and transmission conductor materials used are commonly available, very low-cost, and readily available. The cost of a single capacitively coupled antenna produced using this method is less than 50 yuan.

[0121] Example 5

[0122] Another specific embodiment of the present invention discloses a method for manufacturing a capacitively coupled slip ring, which is used to prepare the capacitively coupled slip ring of embodiment 1, comprising the following steps:

[0123] First, the design and processing of the rotating disk.

[0124] The number of transceivers required is determined based on the amount of data to be transmitted, and a rotating disk of corresponding size is designed based on the actual situation.

[0125] The rotating disk designed in this embodiment has an inner diameter of 1050 mm, an outer diameter of 1300 mm, and a thickness of 45 mm. The rotating disk is made of metal, such as steel.

[0126] A first groove is made along the outer surface of the rotating disk. The width of the first groove is 23 mm and the depth is 3 mm.

[0127] A second groove is formed along the inner surface of the rotating disk. The width of the second groove is 23 mm and the depth is 3 mm. The position of the second groove corresponds to that of the first groove.

[0128] Second, install the transmitting units on the outer surface of the rotating disk (the 2n-1th group, n=1, 2, 3...).

[0129] The data processing unit at the transmitting end is installed on the rotating disk through the positioning hole; the transmitting antenna is installed and fixed in the first groove on the outer surface of the rotating disk by gluing.

[0130] Third, install the transmitting units on the inner surface of the rotating disk (the 2nth group, n=1, 2, 3, ...).

[0131] The data processing unit at the transmitting end is installed on the rotating disk through the positioning hole; the transmitting antenna is fixed in the second groove on the outer surface of the rotating disk by gluing.

[0132] Example 6

[0133] Another specific embodiment of the present invention discloses a method for installing a capacitively coupled slip ring, which is used to install the capacitively coupled slip ring of the first embodiment, comprising the following steps:

[0134] First, install the rotating disk (rotor end) on the CT gantry 11, as shown in Figure 7 shown.

[0135] Second, the receiving units (first receiving units) are installed on the outer surface of the rotating disk (the 2n-1th group, n=1, 2, 3, ...).

[0136] Secure the first receiving unit (i.e., the stator end) to the CT gantry. The first receiving unit consists of a receiving data processing module and a receiving antenna. These two components can be integrated into a single printed circuit board or connected via plug-in connections. The stator end is located outside the rotor end (rotating disk). The receiving antenna must be perfectly aligned with the transmitting antenna, with a spacing of 3 mm.

[0137] Third, the receiving units (second receiving units) are installed on the inner surface of the rotating disk (the 2nth group, n=1, 2, 3, ...).

[0138] Secure the second receiving unit (i.e., the stator end) to the CT gantry. The second receiving unit consists of a receiving data processing module and a receiving antenna. These two components can be integrated into a single printed circuit board or connected via plug-in connections. The stator end is located inside the rotor end (rotating disk). The receiving antenna must be perfectly aligned with the transmitting antenna, with a spacing of 3 mm.

[0139] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for installing a capacitively coupled slip ring, characterized in that: The steps include: Step 1: Install the rotating disk on the CT gantry; Step 2: Install the receiving unit on the outer surface of the rotating disk; Step 3: Install the receiving unit on the inner surface of the rotating disk; The capacitive coupling slip ring includes a rotating disk, a transmitting unit and a receiving unit, wherein the transmitting unit includes a transmitting antenna and a transmitting end data processing unit; The rotating disk is annular with a hollow interior, and a first groove is provided on the inner surface of the rotating disk in a circumferential direction. The shape of the first groove matches the shape of the transmitting antenna, and the transmitting antenna is placed in the first groove; The depth of the first groove is greater than the thickness of the transmitting antenna, and there is a height difference between the upper surface of the transmitting antenna and the outer surface of the rotating disk; The spacing between the transmitting antennas on the inner surface of the rotating disk is 1-2 times the width of the transmitting antenna; The outer surface of the rotating disk is provided with a circumferentially arranged second groove, the shape of the second groove matches the shape of the transmitting antenna, and the transmitting antenna is placed in the second groove; The position of the second groove does not correspond to the position of the first groove.

2. The method for installing a capacitively coupled slip ring according to claim 1, wherein: The step 2 includes installing the receiving unit on the outer surface of the rotating disk on the CT gantry.

3. The method for installing a capacitively coupled slip ring according to claim 1, wherein: The step 3 includes installing the receiving unit on the inner surface of the rotating disk on the CT gantry.

4. The method for installing a capacitively coupled slip ring according to any one of claims 1 to 3, wherein: The step 2 specifically includes fixing the receiving end data processing module of the receiving unit on the CT frame.

5. The method for installing a capacitively coupled slip ring according to claim 4, wherein: The receiving antenna is aligned with the transmitting antenna and there is a certain distance between them.

6. The method for installing a capacitively coupled slip ring according to claim 5, wherein: The distance between the receiving antenna and the transmitting antenna is 1.5-5mm.

7. The method for installing a capacitively coupled slip ring according to claim 6, wherein: The distance between the receiving antenna and the transmitting antenna is 3mm.

8. The method for installing a capacitively coupled slip ring according to claim 3, wherein: The step 3 specifically includes: fixing the receiving end data processing module of the receiving unit on the CT frame.

9. The method for installing a capacitively coupled slip ring according to claim 8, wherein: The receiving antenna is aligned with the transmitting antenna, and there is a 1.5-5 mm gap between them.

10. The method for installing a capacitive coupling slip ring according to claim 9, wherein: The distance between the receiving antenna and the transmitting antenna is 2 mm.

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