Signal transmission device and X-ray CT device

Abstract

To precisely transmit low-frequency signals without increasing the size of a device.SOLUTION: The signal transmitter according to an embodiment is a signal transmitter which transmits a signal to one of a rotation unit and a fixation unit to the other by contactless communication, and includes a ring-shaped housing, a first substrate, and a second substrate. The ring-shaped housing has a metal surface and an opening unit and is set in one of the rotation unit and the fixation unit. The first substrate is arranged in the opening unit and has a first transmission line for transmitting a signal output from a signal source and a reference potential conductor for providing a reference potential of the first transmission line. The second substrate is arranged in an end surface of the ring-shaped housing in a peripheral surface and has a second transmission line folded at the opening unit. The reference potential is on the metal surface. The first transmission line and the second transmission line are electrically connected together. The first substrate has a region in contact with the metal surface.SELECTED DRAWING: Figure 6C

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to a signal transmission device and an X-ray CT device.

Background Art

[0002] A communication system that performs wireless communication using electromagnetic field coupling between adjacent devices is known. For example, a signal transmission device that performs high-speed data communication between a rotating frame and a fixed frame is known. Also, a device that supplies power to a ring-shaped transmission line by a line coupler is known.

[0003] However, in a device that supplies power to a transmission line by a line coupler, for example, when trying to transmit a signal in a baseband band, that is, when transmitting a low-frequency signal, the wavelength becomes long, so the device size becomes large and a large space is required.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to accurately transmit a low-frequency signal without increasing the device size. However, the problems solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. The problems corresponding to the respective effects of each configuration shown in the embodiments described later can also be regarded as other problems.

Means for Solving the Problems

[0006] The signal transmission device according to this embodiment transmits a signal from one rotating part and one stationary part to the other by contactless communication, and comprises a ring-shaped housing, a first substrate, and a second substrate. The ring-shaped housing has a metal surface and an opening, and is installed on one of the rotating part and the stationary part. The first substrate is arranged in the opening and has a first transmission line for transmitting a signal output from a signal source, and a reference potential conductor that provides a reference potential for the first transmission line. The second substrate is arranged on the circumferential end face of the ring-shaped housing and has a second transmission line bent at the opening, with the metal surface as the reference potential. The first transmission line and the second transmission line are electrically connected. The first substrate has a region that contacts the metal surface. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows an example of the configuration of an X-ray CT apparatus to which the communication system constituting the signal transmission device according to this embodiment is applied. [Figure 2] Figure 2 is a schematic diagram showing the communication system that constitutes the signal transmission device according to this embodiment. [Figure 3] Figure 3 shows an example of the configuration of a communication system that constitutes the signal transmission device according to this embodiment. [Figure 4A] Figure 4A shows another example of the configuration of the communication system that constitutes the signal transmission device according to this embodiment. [Figure 4B] Figure 4B is a plan view of the ring-shaped enclosure with 5 lanes, as seen near the power supply section. [Figure 4C] Figure 4C is a perspective view of the ring-shaped housing consisting of three lanes in the dashed area R of Figure 4B, as seen near the power supply section. [Figure 5] Figure 5 is a perspective view of a configuration in which rigid circuit boards are arranged in a ring-shaped housing with three lanes, as seen near the power supply section. [Figure 6A] Figure 6A is a perspective view of a ring-shaped enclosure for one lane, viewed near the power supply section. [Figure 6B]Figure 6B is a perspective view of a configuration in which a rigid circuit board is arranged in a ring-shaped enclosure for one lane, as seen near the power supply section. [Figure 6C] Figure 6C is a perspective view of a configuration in which a rigid circuit board and a flexible printed circuit board are arranged in a ring-shaped enclosure for one lane, as seen near the power supply section. [Figure 7A] Figure 7A is a cross-sectional view taken along the line A-A' in Figure 6C. [Figure 7B] Figure 7B is a cross-sectional view taken along the line B-B' in Figure 6C. [Figure 7C] Figure 7C is a cross-sectional view taken along the line C-C' in Figure 6C. [Figure 7D] Figure 7D is a cross-sectional view taken along the line D-D' in Figure 6C. [Figure 8A] Figure 8A is a perspective view of the structure of this embodiment (simulation model of this embodiment) as seen near the power supply section, with a rigid substrate and a flexible printed circuit board arranged in a ring-shaped housing for one lane. [Figure 8B] Figure 8B is a perspective view of the structure of the comparative example (simulation model of the comparative example) as seen near the power supply section, with a rigid substrate and a flexible printed circuit board arranged in a ring-shaped enclosure for one lane. [Figure 9A] Figure 9A is a cross-sectional view taken along the line E-E' in Figure 8B. [Figure 9B] Figure 9B is a cross-sectional view taken along the line F-F' in Figure 8B. [Figure 9C] Figure 9C is a cross-sectional view taken along the line G-G' in Figure 8B. [Figure 10A] Figure 10A shows the electromagnetic field simulation results of the input reflection characteristics using the simulation models for this embodiment and the comparative example, as simulation results for the structure of this embodiment and the structure of the comparative example. [Figure 10B] Figure 10B shows the electromagnetic field simulation results of the input reflection characteristics using the simulation models for this embodiment and the comparative example, as simulation results for the structure of this embodiment and the structure of the comparative example. [Figure 11A] FIG. 11A is a perspective view of a configuration in which a rigid substrate and a flexible printed circuit board are arranged in a ring-shaped housing for one lane as a structure for explaining differences in the position of a connection portion, as viewed near a power supply portion. [Figure 11B] FIG. 11B is a cross-sectional view taken along the line H-H' of FIG. 11A. [Figure 12] FIG. 12 is an enlarged view of FIG. 7C (a cross-sectional view taken along the line C-C' of FIG. 6C).

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of a signal transmission device and an X-ray CT device will be described in detail with reference to the drawings. Note that the embodiments are not limited to the following embodiments. In addition, the content described in one embodiment is generally applicable to other embodiments as well.

[0009] The communication system constituting the signal transmission device according to the present embodiment is applied to, for example, an X-ray computed tomography (CT) device.

[0010] FIG. 1 is a diagram showing an example of the configuration of an X-ray CT device 1 to which a communication system constituting the signal transmission device according to the present embodiment is applied. The X-ray CT device 1 collects CT image data of a subject. Specifically, the X-ray CT device 1 rotates an X-ray tube and an X-ray detector around the subject substantially at the center, detects X-rays transmitted through the subject, and collects projection data. Then, the X-ray CT device 1 generates CT image data based on the collected projection data. As shown in FIG. 1, the X-ray CT device 1 includes a gantry device 10, a couch device 30, and a console device 40.

[0011] In this embodiment, the rotation axis of the rotating frame 13 in the non-tilted state or the longitudinal direction of the top plate 33 of the patient device 30 is defined as the Z-axis direction. The axis direction perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction. The axis direction perpendicular to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction. Figure 1 shows the gantry device 10 from multiple directions for illustrative purposes, and illustrates the case where the X-ray CT apparatus 1 has one gantry device 10.

[0012] The mounting device 10 includes an X-ray tube 11, an X-ray detector 12, a rotating frame 13, an X-ray high-voltage device 14, a control device 15, a wedge 16, a collimator 17, a data acquisition system (DAS) 18, and a fixed frame 19.

[0013] The X-ray tube 11 is a vacuum tube having a cathode (filament) that generates thermionic electrons and an anode (target) that generates X-rays upon collision with thermionic electrons. The X-ray tube 11 generates X-rays to irradiate the subject P by irradiating thermionic electrons from the cathode to the anode when a high voltage is applied from the X-ray high-voltage device 14. For example, there is a rotating anode type X-ray tube 11 that generates X-rays by irradiating a rotating anode with thermionic electrons.

[0014] The wedge 16 is a filter used to adjust the amount of X-rays irradiated from the X-ray tube 11. Specifically, the wedge 16 is a filter that transmits and attenuates the X-rays irradiated from the X-ray tube 11 so that the X-rays irradiated from the X-ray tube 11 to the subject P have a predetermined distribution. For example, the wedge 16 is a wedge filter or a bow-tie filter, which is a filter made of aluminum or the like processed to have a predetermined target angle and thickness.

[0015] The collimator 17 is a lead plate or the like used to narrow the irradiation range of X-rays that have passed through the wedge 16, and a slit is formed by combining multiple lead plates or the like. The collimator 17 is sometimes called an X-ray diaphragm. In Figure 1, the wedge 16 is shown to be placed between the X-ray tube 11 and the collimator 17, but the collimator 17 may also be placed between the X-ray tube 11 and the wedge 16. In this case, the wedge 16 transmits and attenuates the X-rays that are irradiated from the X-ray tube 11 and whose irradiation range has been limited by the collimator 17.

[0016] The X-ray detector 12 has multiple detection elements for detecting X-rays. Each detection element in the X-ray detector 12 detects X-rays irradiated from the X-ray tube 11 that have passed through the subject P, and outputs a signal corresponding to the detected X-ray amount to the DAS 18. The X-ray detector 12 has, for example, multiple rows of detection elements arranged in the channel direction (channel direction) along a single arc centered on the focal point of the X-ray tube 11. The X-ray detector 12 has, for example, a structure in which multiple rows of detection elements, each arranged in the channel direction, are arranged in the row direction (slice direction, row direction).

[0017] For example, the X-ray detector 12 is an indirect conversion type detector having a grid, a scintillator array, and a photosensor array. The scintillator array has multiple scintillators. The scintillators have scintillator crystals that output light in a quantity of photons corresponding to the amount of incident X-rays. The grid is arranged on the X-ray incident side of the scintillator array and has an X-ray shielding plate that absorbs scattered X-rays. The grid is sometimes called a collimator (one-dimensional collimator or two-dimensional collimator). The photosensor array has the function of converting the amount of light from the scintillators into an electrical signal, and has a photosensor such as a photodiode. The X-ray detector 12 may also be a direct conversion type detector having semiconductor elements that convert incident X-rays into electrical signals.

[0018] The X-ray high-voltage device 14 includes an electrical circuit such as a transformer and a rectifier, a high-voltage generator that generates a high voltage to be applied to the X-ray tube 11, and an X-ray control device that controls the output voltage according to the X-rays generated by the X-ray tube 11. The high-voltage generator may be of the transformer type or the inverter type. The X-ray high-voltage device 14 may be installed on the rotating frame 13 or on the fixed frame 19. Here, the fixed frame 19 is a frame that rotatably supports the rotating frame 13 and has a rotation mechanism for rotating the rotating frame 13. The rotating frame 13 and the fixed frame 19 are examples of a rotating part and a fixed part, respectively.

[0019] The DAS18 collects X-ray signals detected by each detection element of the X-ray detector 12. For example, the DAS18 has an amplifier that performs amplification processing on the electrical signals output from each detection element, and an A / D converter that converts the electrical signals into digital signals, thereby generating detection data. The DAS18 is implemented, for example, by a processor. The DAS18 is an example of a data acquisition device.

[0020] The rotating frame 13 is an annular frame that supports the X-ray tube 11 and the X-ray detector 12 opposite each other and rotates the X-ray tube 11 and the X-ray detector 12 by the control device 15. For example, the rotating frame 13 is a casting made of aluminum. In addition to the X-ray tube 11 and the X-ray detector 12, the rotating frame 13 can also support an X-ray high-voltage device 14, a wedge 16, a collimator 17, a DAS 18, etc. Furthermore, the rotating frame 13 can also support various other components not shown in Figure 1.

[0021] Signal transmission devices are provided on both the rotating frame 13 and the fixed frame 19, which is the non-rotating part of the mounting device 10. For example, data generated by the DAS 18 (collected X-ray signals) is transmitted wirelessly from the signal transmission device on the rotating frame 13 to the signal transmission device on the fixed frame 19 and then forwarded to the console device 40. Also, for example, control signals transmitted by the console device 40 to the rotating frame 13 are transmitted wirelessly from the signal transmission device on the fixed frame 19 to the signal transmission device on the rotating frame 13. The signal transmission devices on the rotating frame 13 and the signal transmission devices on the fixed frame 19 constitute a communication system 600, which will be described later.

[0022] The control device 15 includes a processing circuit with a CPU (Central Processing Unit), etc., and a drive mechanism such as a motor and actuator. The control device 15 receives input signals from the input interface 43 and controls the operation of the frame device 10 and the bed device 30. For example, the control device 15 controls the rotation of the rotating frame 13, the tilt of the frame device 10, and the operation of the bed device 30 and the top plate 33. To give one example, as a control to tilt the frame device 10, the control device 15 rotates the rotating frame 13 around an axis parallel to the X-axis direction based on the input tilt angle information. The control device 15 may be installed on the frame device 10 or on the console device 40.

[0023] The patient bed apparatus 30 is a device for placing and moving the subject P to be photographed, and comprises a base 31, a patient bed drive device 32, a top plate 33, and a support frame 34. The base 31 is a housing that supports the support frame 34 so that it can move in the vertical direction. The patient bed drive device 32 is a drive mechanism that moves the top plate 33 on which the subject P is placed in the direction of the long axis of the top plate 33, and includes a motor and actuator, etc. The top plate 33, which is provided on the upper surface of the support frame 34, is a plate on which the subject P is placed. In addition to moving the top plate 33, the patient bed drive device 32 may also move the support frame 34 in the direction of the long axis of the top plate 33.

[0024] The console device 40 includes a memory 41, a display 42, an input interface 43, and a processing circuit 44. Although the console device 40 is described separately from the mounting device 10, the mounting device 10 may include the console device 40 or some of its components.

[0025] Memory 41 can be implemented using, for example, semiconductor memory elements such as RAM (Random Access Memory) or flash memory, a hard disk, or an optical disc. Memory 41 stores, for example, projection data or CT image data. It can also store, for example, programs for circuits included in the X-ray CT apparatus 1 to perform their functions. Alternatively, memory 41 may be implemented using a group of servers (cloud) connected to the X-ray CT apparatus 1 via a network.

[0026] The display 42 displays various types of information. For example, the display 42 may display various images generated by the processing circuit 44, or it may display a GUI (Graphical User Interface) to receive various operations from the operator. For example, the display 42 may be a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 42 may also be mounted on the stand device 10. Furthermore, the display 42 may be a desktop type, or it may be composed of a tablet terminal or the like that can communicate wirelessly with the console device 40.

[0027] The input interface 43 receives various input operations from the operator, converts the received input operations into electrical signals, and outputs them to the processing circuit 44. For example, the input interface 43 receives input operations from the operator such as reconstruction conditions when reconstructing CT image data, and image processing conditions when generating post-processed images from CT image data. For example, the input interface 43 can be implemented by a mouse, keyboard, trackball, switch, button, joystick, touchpad that performs input operations by touching the operating surface, touchscreen that integrates a display screen and a touchpad, non-contact input circuit using an optical sensor, audio input circuit, etc. The input interface 43 may also be provided on the mounting device 10. Furthermore, the input interface 43 may consist of the console device 40 main unit and a tablet terminal that can communicate wirelessly. In addition, the input interface 43 is not limited to those equipped with physical operating components such as a mouse or keyboard. For example, an electrical signal processing circuit that receives electrical signals corresponding to input operations from an external input device provided separately from the console device 40 and outputs these electrical signals to the processing circuit 44 is also included as an example of the input interface 43.

[0028] The processing circuit 44 controls the operation of the entire X-ray CT apparatus 1. For example, the processing circuit 44 performs system control functions 440, scan control functions 441, preprocessing functions 442, reconstruction processing functions 443, and display control functions 444.

[0029] The system control function 440 controls various functions of the processing circuit 44 based on input operations received from the operator via the input interface 43.

[0030] The scan control function 441 performs an X-ray scan on the subject P. For example, the scan control function 441 controls the scan based on input operations received from the operator via the input interface 43. Specifically, the scan control function 441 controls the output voltage from the high-voltage generator by sending a control signal to the X-ray high-voltage device 14 based on the input operation. The scan control function 441 also controls data acquisition by the DAS 18 by sending a control signal to the DAS 18.

[0031] The preprocessing function 442 generates preprocessed data by performing preprocessing on the X-ray detection data transmitted from the DAS18. Specifically, the preprocessing function 442 generates preprocessed data by performing correction processes such as logarithmic transformation, offset correction, sensitivity correction, and beam hardening correction. Note that the data before preprocessing (X-ray detection data) and the data after preprocessing are sometimes collectively referred to as projection data.

[0032] The reconstruction processing function 443 generates CT image data by reconstructing the projection data generated by the preprocessing function 442 using various reconstruction methods (for example, back projection methods such as FBP (Filtered Back Projection) and iterative approximation methods). The reconstruction processing function 443 also stores the generated CT image data in the memory 41.

[0033] The display control function 444 displays various images generated by the processing circuit 44 on the display 42. For example, the display control function 444 displays CT image data generated by the reconstruction processing function 443 on the display 42.

[0034] In the X-ray CT scanner 1 shown in Figure 1, each processing function is stored in memory 41 in the form of a program that can be executed by a computer. The processing circuit 44 is a processor that realizes the function corresponding to each program by reading and executing the program from memory 41. In other words, the processing circuit 44, when it has read a program, has the function corresponding to the read program.

[0035] In the above description, the term "processor" refers to circuits such as CPUs (Central Processing Units), GPUs (Graphics Processing Units), and Application Specific Integrated Circuits (ASICs). It also refers to circuits such as programmable logic devices. Examples of programmable logic devices include Simple Programmable Logic Devices (SPLDs) and Complex Programmable Logic Devices (CPLDs). Another example of a programmable logic device is a Field Programmable Gate Array (FPGA). When the processor is a CPU, it functions by reading and executing a program stored in memory 41. On the other hand, when the processor is an ASIC, instead of storing the program in memory 41, the program is directly embedded within the processor's circuitry. Note that each processor in this embodiment is not limited to being configured as a single circuit; multiple independent circuits may be combined to form a single processor, and its functions may be realized through this configuration. Furthermore, the multiple components shown in Figure 1 may be integrated into a single processor to realize their functions.

[0036] Next, the principle of wireless communication in a communication system to which the signal transmission device according to this embodiment is applied will be described.

[0037] Figure 2 is a schematic diagram showing the communication system that constitutes the signal transmission device according to this embodiment. As shown in Figure 2, the communication system comprises a transmitting signal transmission device 100 and a receiving signal transmission device 200.

[0038] The transmitting signal transmission device 100 is configured to be long in one direction and functions as a transmitting coupler for transmitting wireless signals. The signal transmission device 100 comprises a set of transmission lines 101 for differential transmission, a signal source 102, a differential transmission buffer 103, a termination section 104 which is a termination resistor, a metal section 105, and a flexible printed circuit board 107.

[0039] A set of transmission lines 101 for differential transmission consists of two parallel linear conductor members and is the transmission line on the transmitting side that transmits wireless signals. The transmission line 101 is formed as a pattern on a flexible printed circuit board 107. Data output from the signal source 102 is input as a differential signal via a differential transmit buffer 103 connected to one end of the transmission line 101. Here, the configuration of the signal source 102 and differential transmit buffer 103 is described as an example of the transmitting side circuit configuration, but it is not limited to the configuration in Figure 2, and a power supply circuit for driving the differential transmit buffer, a distributor, various filters, amplifiers, attenuators and other electronic components may be mounted. The other end of the transmission line 101 is terminated with a termination section 104 having an impedance approximately equal to the characteristic impedance of the transmitting side transmission line 101.

[0040] The metal part 105 has a roughly U-shaped cross-sectional structure with a pair of side walls and a bottom. The pair of side walls of the metal part 105 are in contact with the plane of the flexible printed circuit board 107, and function as a support for the flexible printed circuit board 107. The metal part 105 and the flexible printed circuit board 107 form a space enclosed by the pair of side walls and bottom of the metal part 105 and the flexible printed circuit board 107. The transmission line 101 consists of two conductor members arranged in parallel along the longitudinal direction, and the inner surface of the flexible printed circuit board 107 is connected to the metal part 105 to form a ground (reference potential), thereby forming a transmission line for differential transmission, also known as a differential microstrip line.

[0041] The receiving signal transmission device 200 is positioned at a distance from the transmitting signal transmission device 100 and functions as a receiving coupler for receiving wireless signals. The signal transmission device 200 comprises a circuit board 201, a differential coupler 202, and a receiving circuit 203.

[0042] The receiving signal transmission device 200 corresponds to an example of a device that communicates with the transmitting signal transmission device 100. The differential coupler 202 (hereinafter simply referred to as coupler 202) is a set of two parallel linear conductor members and is a receiving transmission line that receives wireless signals from the transmission line 101. The coupler 202 is formed as a pattern on the substrate 201. The coupler 202 is movable substantially parallel to the longitudinal direction of the transmission line 101. The coupler 202 and the transmission line 101 overlap at least partially when viewed from a direction perpendicular to the direction of movement of the receiving signal transmission device 200 and from a direction perpendicular to the direction in which the two conductor members are adjacent. The signal output from the coupler 202 is detected as a received signal by the receiving circuit 203.

[0043] The signal output from the signal source 102 is a digital signal of "1" or "0". Here, if the input impedance of the receiving circuit 203 is low, the signal output from the coupler 202 becomes an edge signal dependent on the rising and falling edges. In this case, by using a comparator with a hysteresis voltage in the receiving circuit 203, the original "1" or "0" signal can be demodulated from the edge signal. Also, if the input impedance of the receiving circuit 203 is high, a waveform similar to the signal waveform propagated in the transmission line 101 is output from the coupler 202. In this case, by using an amplifier or the like in the receiving circuit 203 to amplify the signal to a size that can be processed digitally, wireless communication becomes possible.

[0044] Next, the configuration of the communication system 600 using the principle described above will be explained. Note that components similar to those in Figure 2 are denoted by the same reference numerals and their explanations are omitted.

[0045] Figure 3 shows an example of the configuration of a communication system 600 that constitutes a signal transmission device according to this embodiment. The communication system 600 comprises a transmitting signal transmission device 300 and a receiving signal transmission device 200.

[0046] The transmitting signal transmission device 300 is configured in a ring shape and functions as a transmitting coupler (long coupler) that transmits wireless signals. Here, the signal transmission device 300 corresponds to the signal transmission device 100 in Figure 2.

[0047] The transmitting signal transmission device 300 comprises flexible printed circuit boards 301a and 301b, transmission lines 303a and 303b, a ring-shaped housing 304, and an input-side board 305. Transmission lines 303a and 303b are formed on the flexible printed circuit boards 301a and 301b, respectively. Multiple transmission lines may be arranged parallel to transmission line 303a and transmission line 303b, in which case multi-channel signal transmission becomes possible. Here, each of the flexible printed circuit boards 301a and 301b corresponds to the flexible printed circuit board 107 in Figure 2, and each of the transmission lines 303a and 303b corresponds to a pair of transmission lines 101 for differential transmission in Figure 2.

[0048] Furthermore, the flexible printed circuit boards 301a and 301b are formed so as to wrap the transmission lines 303a and 303b around the ring-shaped housing 304 in an annular manner. The ring-shaped housing 304 has a substantially U-shaped cross-sectional structure with a pair of side walls and a bottom. Here, the ring-shaped housing 304 corresponds to the metal part 105 in Figure 2.

[0049] As shown in Figure 3, when communication is performed using the outer peripheral surface (outer peripheral surface) of the ring-shaped housing 304, the flexible printed circuit boards 301a and 301b are arranged circumferentially on the outer peripheral surface of the ring-shaped housing 304 so that the transmission lines 303a and 303b are formed on the outer peripheral surface of the ring-shaped housing 304. Support members on the ring-shaped housing 304 are also formed on the outer peripheral surface of the ring-shaped housing 304, and these support members support the flexible printed circuit boards. Conversely, when communication is performed using the inner peripheral surface (inner peripheral surface) of the ring-shaped housing 304, the transmission lines 303a and 303b are formed as patterns on the inner peripheral surface of the ring-shaped housing 304.

[0050] The transmission lines 303a and 303b are formed along the longitudinal direction of the flexible printed circuit boards 301a and 301b, respectively. The transmission lines 303a and 303b are arranged in a substantially straight line along the circumferential direction of the ring-shaped housing 304 without overlapping each other. Specifically, the transmission line 303a is arranged along approximately half of the circumference of the ring-shaped housing 304 (approximately 180°), and the transmission line 303b is arranged along approximately half of the circumference of the ring-shaped housing 304 (approximately 180°).

[0051] Furthermore, one end (start end) of the transmission lines 303a and 303b in the circumferential direction is connected to the power supply unit to which the signal is input, and the other end is terminated by termination resistors 310a and 310b (termination section), respectively. The start end and termination section of the transmission lines 303a and 303b are positioned opposite each other with the rotation axis O of the rotation mechanism 400 in between. Here, a shielding plate 320 for blocking interference signals is placed between the termination resistors 310a and 310b. Each of the termination resistors 310a and 310b corresponds to the termination section 104 in Figure 2.

[0052] As shown in Figure 3, the direction of the signal transmitted along transmission line 303a and the direction of the signal transmitted along transmission line 303b are opposite to each other. Transmission lines 303a and 303b each consist of two conductor members arranged in parallel along their longitudinal direction, and the inner surface of the ring-shaped housing 304 is used as ground (reference potential), thereby forming a transmission line for differential transmission, also known as a differential microstrip line.

[0053] The input-side board 305 is positioned close to the power supply sections of the transmission lines 303a and 303b. A differential amplifier and the like are mounted on the input-side board 305. Here, the differential amplifier corresponds to the differential transmit buffer 103 in Figure 2.

[0054] The receiving signal transmission device 200 moves relative to the transmission lines 303a and 303b of the transmitting signal transmission device 300, while maintaining a constant distance from them. Since the signal transmission device 200 has the same configuration as the signal transmission device 200 in Figure 2, a detailed explanation is omitted.

[0055] In this embodiment, the rotating part is connected to the transmitting signal transmission device 300, and the fixed part is connected to the receiving signal transmission device 200. Therefore, since the transmitting signal transmission device 300 is rotatable around the rotation axis O, the transmitting signal transmission device 300 and the receiving signal transmission device 200 can communicate while rotating relative to each other. Here, the transmitting signal transmission device 300 connected to the rotating part corresponds to the signal transmission device provided on the rotating frame 13 of the X-ray CT apparatus 1 in Figure 1. Also, the receiving signal transmission device 200 connected to the fixed part of the rotating mechanism 400 corresponds to the signal transmission device provided on the fixed frame 19 of the X-ray CT apparatus 1 in Figure 1.

[0056] The rotating part may be connected to the receiving signal transmission device 200, and the fixed part of the rotating mechanism 400 may be connected to the transmitting signal transmission device 300. Alternatively, the first rotating part may be connected to the receiving signal transmission device 200, and the second rotating part may be connected to the transmitting signal transmission device 300, with both the transmitting signal transmission device 300 and the receiving signal transmission device 200 being able to rotate independently around the rotation axis O.

[0057] Alternatively, a shielding plate may be placed between the end of the flexible printed circuit board 301a on which the transmission line 303a is formed and the end of the flexible printed circuit board 301b on which the transmission line 303b is formed.

[0058] Furthermore, although this embodiment has described a transmission system with 1 channel, in a transmission system with multiple channels, the transmission lines 303a and 303b can be arranged at an interval of 90° or less, rather than approximately 180°, and multiple power supply units may be provided. It is also possible to arrange multiple transmission lines parallel to the transmission lines 303a and 303b. In addition, although the above embodiment described the case where the signal transmission device 300 is the transmitting side and the signal transmission device 200 is the receiving side, it is not limited to this case, and the signal transmission device 300 may be the receiving side and the signal transmission device 200 may be the transmitting side. Furthermore, the signal transmission devices 200 and 300 may be configured to transmit and receive signals.

[0059] The above-described transmission line is a differential microstrip line, but it is not limited to this. Other types of differential transmission lines may also be used, such as differential coplanar lines or grounded differential coplanar lines. Furthermore, the above-described transmission line is a differential transmission line, but it is not limited to this. It does not have to be differential as long as external noise and unwanted radiation are not a problem.

[0060] The communication system constituting the signal transmission device according to this embodiment has been described above. With this configuration, the signal transmission device according to this embodiment transmits low-frequency signals with high accuracy without increasing the size of the device.

[0061] For example, when supplying power to a ring-shaped transmission line, if a signal is to be transmitted in the baseband bandwidth, specifically when transmitting a low-frequency signal, the wavelength becomes long, resulting in a larger device size and requiring a large space. In contrast, in the signal transmission device according to this embodiment, as shown in Figure 3, a long coupler is used as the transmitting signal transmission device 300, so there is no need to increase the size of the device. Therefore, in order to accurately transmit low-frequency signals by optimizing the reflection characteristics, the signal transmission device according to this embodiment has the following configuration.

[0062] Specifically, the signal transmission device according to this embodiment transmits a signal from one of a rotating part (rotating frame 13) and a fixed part (fixed frame 19) to the other by contactless communication, and comprises a ring-shaped housing, a first substrate, and a second substrate. The ring-shaped housing has a metal surface and an opening, and is installed on one of the rotating part and the fixed part. The first substrate is arranged in the opening and has a first transmission line that transmits a signal output from a signal source 102, and a reference potential conductor that provides a reference potential for the first transmission line. The second substrate is arranged on the circumferential end face of the ring-shaped housing and has a second transmission line bent at the opening, with the metal surface as the reference potential. The first transmission line and the second transmission line are electrically connected. The first substrate has a region that contacts the metal surface.

[0063] In the example shown in Figure 3, the ring-shaped housing 304 is positioned on the rotating part. In this case, the signal source 102 is the DAS 18, and the signal output from the signal source 102 is the X-ray signal collected by the DAS 18.

[0064] First, the ring-shaped enclosure will be explained using Figures 4A to 4C and Figure 6A.

[0065] Figure 4A shows another example of the configuration of the communication system 600 that constitutes the signal transmission device according to this embodiment. In the example shown in Figure 4A, unlike the example shown in Figure 3, communication is performed using the inner surface of the ring-shaped housing 304. That is, in the example shown in Figure 4A, the flexible printed circuit boards 301a and 301b of the transmitting signal transmission device 300 are arranged circumferentially on the inner surface of the ring-shaped housing 304 so that the transmission lines 303a and 303b of the transmitting signal transmission device 300 are formed as patterns on the inner surface of the ring-shaped housing 304. Hereafter, the case in which communication is performed using the inner surface of the ring-shaped housing 304 will be explained as an example.

[0066] Figures 4B and 4C are enlarged views showing an example of the configuration of the ring-shaped housing 304 near the power supply section. Figure 4B is a plan view of the ring-shaped housing 304 for 5 lanes as seen near the power supply section. Here, Figure 4C is a perspective view of the ring-shaped housing 304 for 3 lanes as seen near the power supply section in the dashed area R of Figure 4B. As shown in Figures 4B and 4C, the ring-shaped housing 304 has multiple ring-shaped wall sections arranged at intervals in the axial direction, and the wall sections have divided regions divided in the circumferential direction. The ring-shaped housing 304 has a metal surface and an opening, and the opening is formed by arranging multiple wall sections so that the divided regions are in the same position in the circumferential direction.

[0067] Figure 6A is a perspective view of a ring-shaped housing 304 for one lane, viewed near the power supply section. As shown in Figure 6A, the ring-shaped housing 304 has a base body 304A which is a metal member, support members 304B and 304C which form a metal surface on the base body 304A, and an opening 304D. The support members 304B and 304C are wall portions and correspond to a pair of side walls of the metal portion 105. The base body 304A corresponds to the bottom of the metal portion 105. The opening 304D shown in Figures 4B, 4C, and 6A is formed by the support members 304B and 304C and the region where the base body 304A is divided.

[0068] Next, the first substrate will be explained using Figures 5, 6B, 6C, 7A, and 7B.

[0069] Figure 5 is a perspective view of a configuration in which rigid substrates 111 are arranged in a ring-shaped housing 304 with three lanes, as seen near the power supply unit. Figure 6B is a perspective view of a configuration in which rigid substrates 111 are arranged in a ring-shaped housing 304 with one lane, as seen near the power supply unit. Figure 6C is a perspective view of a configuration in which rigid substrates 111 and flexible printed circuit boards 107 are arranged in a ring-shaped housing 304 with one lane, as seen near the power supply unit. Here, Figure 7A is a cross-sectional view taken along the line A-A' in Figure 6C. Figure 7B is a cross-sectional view taken along the line B-B' in Figure 6C. The rigid substrate 111 is an example of a first substrate.

[0070] As shown in Figures 5, 6B, and 6C, the rigid substrate 111 is positioned approximately normal to the ring-shaped housing 304. As shown in Figure 6B, the rigid substrate 111 is positioned in the opening 304D and has transmission lines 111a and 111b that transmit signals output from the signal source 102. Furthermore, as shown in Figures 5, 6B, and 7A, the rigid substrate 111 has a GND wiring 121 that provides a reference potential for the transmission lines 111a and 111b. The transmission lines 111a and 111b are examples of first transmission lines, and the GND wiring 121 is an example of a reference potential conductor.

[0071] As shown in Figure 7A, the rigid substrate 111 has two main surfaces 111-1 and 111-2, and two side surfaces 111-3 and 111-4 connecting the two main surfaces 111-1 and 111-2. The two side surfaces 111-3 and 111-4 are parallel to the signal transmission direction. Transmission lines 111a and 111b are located on one of the two main surfaces 111-1 and 111-2, the main surface 111-1, and the GND wiring 121 is located on the other main surface 111-2.

[0072] Here, as shown in Figures 6B and 6C, the rigid substrate 111 has a region R1 that contacts the metal surfaces of the support members 304B and 304C. Specifically, the rigid substrate 111 has a region R1 that is sandwiched between two adjacent wall portions (support members 304B and 304C). For example, as shown in Figure 7B, in region R1, the two sides 111-3 and 111-4 each contact the support members 304B and 304C, respectively. The GND wiring 121 is also formed up to the region between the two adjacent wall portions (support members 304B and 304C).

[0073] Next, the second substrate will be explained using Figures 6C, 7C, and 7D.

[0074] As described above, Figure 6C is a perspective view of a configuration in which a rigid substrate 111 and a flexible printed circuit board 107 are arranged in a ring-shaped housing 304 for one lane, as seen near the power supply section. Here, Figure 7C is a cross-sectional view taken along the line C-C' in Figure 6C. Figure 7D is a cross-sectional view taken along the line D-D' in Figure 6C. The flexible printed circuit board 107 is an example of a second substrate.

[0075] As shown in Figure 6C, the flexible printed circuit board 107 is positioned on the circumferential end face of the ring-shaped housing 304 and has transmission lines 101a and 101b bent at the opening 304D, with the metal surface (support members 304B and 304C) as the reference potential. The flexible printed circuit board 107 corresponds to the flexible printed circuit board 107 in Figure 2 and the flexible printed circuit boards 301a and 301b in Figure 3. The transmission lines 101a and 101b correspond to the pair of transmission lines 101 for differential transmission in Figure 2 and the transmission lines 303a and 303b in Figure 3. Furthermore, transmission lines 101a and 101b are examples of second transmission lines.

[0076] As shown in Figures 6C and 7D, the support members 304B and 304C are members for supporting the flexible printed circuit board 107. The characteristic impedance of the transmission lines 101a and 101b of the flexible printed circuit board 107 is determined using the ring-shaped housing 304 as the reference potential (grant). The other ends of the transmission lines 101a and 101b are terminated at termination points (termination resistors 310a and 310b in Figure 3) with an impedance approximately equal to the characteristic impedance. Furthermore, the transmission lines 101a and 101b are optimized to obtain the electric field coupling necessary for wireless communication.

[0077] As shown in Figures 6C and 7C, the transmission lines 111a and 111b of the rigid substrate 111 and the transmission lines 101a and 101b of the flexible printed circuit board 107 are electrically connected. Specifically, as shown in Figure 6C, the transmission lines 111a and 111b and the transmission lines 101a and 101b have a connection part R2 on the rigid substrate 111 that is electrically connected. The connection part R2 corresponds to the power supply part. The connection part R2 is located in or near region R1 where the rigid substrate 111 is in contact with the support members 304B and 304C. Near region R1 refers to a location downstream of region R1 in the signal transmission direction.

[0078] For example, as shown in Figure 6C, the flexible printed circuit board 107 is supported by the radial end faces of two adjacent wall portions (support members 304B and 304C), and is positioned along the circumferential direction of the ring-shaped housing 304. Furthermore, it is bent radially at the point where the support members 304B and 304C are separated. As a result, the transmission lines 101a and 101b of the flexible printed circuit board 107 have extension portions 110a and 110b at the connection portion R2, which extend in a direction different from the longitudinal direction (circumferential direction) of the transmission lines 101a and 101b (radial direction). At the connection portion R2, the transmission lines 111a and 111b and the extension portions 110a and 110b are electrically connected on the rigid substrate 111.

[0079] Furthermore, as shown in Figure 6C, the line widths of the transmission lines 101a and 101b formed in the circumferential direction of the ring-shaped housing 304 are different from the line widths of the transmission lines (extension sections 110a and 110b) formed at the connection section R2. When connecting transmission lines with different line widths, the signal input at the connection section R2 may be reflected, potentially degrading the communication quality. Therefore, the line widths of the extension sections 110a and 110b are set to be approximately equal to the line widths of the transmission lines 111a and 111b on the rigid substrate 111. The transmission lines 111a and 111b formed on the rigid substrate 111 are designed to optimize their reflection characteristics.

[0080] In this embodiment, the reference potential gradually transitions from the GND wiring 121 on the rigid substrate 111 to the ring-shaped housing 304, as shown in the structures in Figures 4B, 4C, 5, 6A to 6C, and 7A to 7D. That is, in the structure of this embodiment, the rigid substrate 111 has a region R1 in contact with a metal surface (support members 304B and 304C of the ring-shaped housing 304), so that the reference potential smoothly transitions from the GND wiring 121 on the rigid substrate 111 to the ring-shaped housing 304, as shown in Figures 7A to 7D.

[0081] In the cross-section shown in Figure 7A, the transmission lines 111a and 111b of the rigid substrate 111 use the GND wiring 121 of the rigid substrate 111 as their reference potential.

[0082] In the cross-section shown in Figure 7B, the ring support members 304B and 304C extend to the surface of the rigid substrate 111. Therefore, the transmission lines 111a and 111b of the rigid substrate 111 use both the GND wiring 121 of the rigid substrate 111 and the ring-shaped housing 304 as reference potentials.

[0083] In the cross-section shown in Figure 7C, the transmission lines 111a and 111b of the rigid substrate 111, and the transmission lines 101a and 101b of the flexible printed circuit board 107, use both the GND wiring 121 of the rigid substrate 111 and the ring-shaped housing 304 as reference potentials.

[0084] In the cross-section shown in Figure 7D, the transmission lines 101a and 101b of the flexible printed circuit board 107 use the ring-shaped housing 304 as the reference potential.

[0085] Thus, in the structure of this embodiment, the rigid substrate 111 has a region R1 in contact with a metal surface (support members 304B and 304C of the ring-shaped housing 304), allowing the reference potential to smoothly transition from the GND wiring 121 on the rigid substrate 111 to the ring-shaped housing 304. For this reason, the structure of this embodiment can reduce the amount of reflection and loss between transmission lines with different reference potentials.

[0086] This reason will be explained using this embodiment and a comparative example.

[0087] Figure 8A is a perspective view of the structure of this embodiment (simulation model of this embodiment) as seen near the power supply section, in which a rigid substrate 111 and a flexible printed circuit board 107 are arranged in a ring-shaped housing 304 for one lane. Here, the cross-sectional views taken along the arrows A-A', B-B', C-C', and D-D' in Figure 8A are the same as the cross-sectional views taken along the arrows shown in Figures 7A to 7D.

[0088] As described above, in the structure of this embodiment, the rigid substrate 111 has a region R1 in contact with a metal surface (support members 304B and 304C of the ring-shaped housing 304), so that the reference potential smoothly transitions from the GND wiring 121 on the rigid substrate 111 to the ring-shaped housing 304.

[0089] Figure 8B is a perspective view of a comparative example structure (simulation model of the comparative example) for running the simulation, showing a configuration in which a rigid substrate 1111 and a flexible printed circuit board 1107 are arranged in a ring-shaped housing 1304 for one lane, as seen near the power supply section. Figures 9A to 9C are cross-sectional views taken along the lines E-E', F-F', and G-G' in Figure 8B, respectively.

[0090] In the comparative example structure, the rigid substrate 1111 does not have a region that contacts the metal surface (support members 1304B and 1304C of the ring-shaped housing 1304). Therefore, in the comparative example structure, in the cross-section shown in Figure 9A, the transmission lines 1111a and 1111b of the rigid substrate 1111 operate with the GND wiring 1121 of the rigid substrate 1111 as the reference potential, and in the cross-section shown in Figure 9B, similar to the case in Figure 9A, the transmission lines 1111a and 1111b of the rigid substrate 1111 operate with the GND wiring 1121 of the rigid substrate 1111 as the reference potential. However, in the cross-section shown in Figure 9B, the ring support members 1304B and 1304C do not extend to the surface of the rigid substrate 1111, so the transmission lines 1111a and 1111b of the rigid substrate 1111 do not use the ring-shaped housing 304 (ring support members 304B and 304C) as the reference potential. In the cross-section shown in Figure 9C, the transmission lines 1101a and 1101b of the flexible printed circuit board 1107 operate with the ring-shaped housing 1304 (ring support members 304B and 304C) as the reference potential. Thus, in the comparative example structure, the rigid substrate 1111 does not have a region that contacts a metal surface, so the reference potential does not smoothly transition from the GND wiring 1121 on the rigid substrate 1111 to the ring-shaped housing 1304.

[0091] Figures 10A and 10B show the electromagnetic field simulation results of the input reflection characteristics using the simulation models for this embodiment and the comparative example, as simulation results for the structure of this embodiment and the structure of the comparative example.

[0092] In Figure 10A, the solid line represents the results of the simulation model of this embodiment, and the dashed line represents the results of the simulation model of the comparative example. In Figure 10A, the horizontal axis represents frequency, and the vertical axis represents the differential input reflection amount. A smaller reflection amount indicates better communication quality. In Figure 10A, both models are below -20dB in the frequency range of 6GHz or less, but it can be seen in particular that the simulation model of this embodiment has a smaller reflection amount than the simulation model of the comparative example. From the viewpoint of error rate, it is desirable to minimize reflection as much as possible, so the superiority of this embodiment is demonstrated.

[0093] Figure 10B shows the electromagnetic field simulation results for the transfer characteristics. Similar to Figure 10A, the solid line represents the results analyzed by the simulation model of this embodiment, and the dashed line represents the results analyzed by the simulation model of the comparative example. In Figure 10B, the horizontal axis represents frequency, and the vertical axis represents the differential transfer amount. In Figure 10B, it can be seen that the simulation model of this embodiment has a smaller reflection amount, indicating that the signal is transmitted to the transmitting coupler without loss.

[0094] Thus, in this embodiment, the structure, based on its reflection and transmission characteristics, can suppress the impact of reflection on communication from low frequencies and prevent a decrease in communication accuracy.

[0095] Furthermore, in the structure of this embodiment, the connection R2 in which the transmission lines 111a, 111b and the transmission lines 101a, 101b are electrically connected on the rigid substrate 111 can also suppress the effect on differential impedance as follows.

[0096] Figure 11A is a perspective view of a configuration near the power supply section, where a rigid substrate 111 and a flexible printed circuit board 107 are arranged in a ring-shaped housing 304 for one lane, as a structure to explain the difference in the position of the connection part. Figure 11B is a cross-sectional view taken along the line H-H' in Figure 11A. In the example shown in Figures 11A and 11B, the transmission lines 111a and 111b and the transmission lines 101a and 101b are electrically connected on the flexible printed circuit board 107.

[0097] As shown in Figure 11B, the transmission lines 101a and 101b of the flexible printed circuit board 107, which is placed on the ring-shaped housing 304, communicate with the receiving signal transmission device 200 by electric field coupling, and therefore the transmission line width and the distance between transmission line widths are set. In the case of differential transmission lines, if electromagnetic fields generated from electronic devices in the environment link between differential transmission lines, the differential circuit cannot cancel them out, degrading communication performance. For this reason, the spacing between differential transmission lines is set to be relatively small. Therefore, as shown in Figure 11B, when the flexible printed circuit board 107 is connected to the rigid board 111 by electrical connection members such as solder or anisotropic conductive film (ACF), the connection members shorten the distance between differential transmission lines, making it easier for impedance disturbances to occur. Furthermore, when the rigid board 111 is connected to the flexible printed circuit board 107, the thickness at the connection point differs from that of other transmission line sections, making it highly likely that the gap with the receiving signal transmission device 200 will be shortened at the connection point. In electric field coupling communication, the signal level changes depending on the distance between the transmitting and receiving couplers, which can also be a factor in degrading communication performance.

[0098] Figure 12 is an enlarged view of Figure 7C (a cross-sectional view taken along the line C-C' in Figure 6C). In the example shown in Figure 12, in this embodiment, transmission lines 111a and 111b and transmission lines 101a and 101b are electrically connected on the rigid substrate 111.

[0099] As shown in Figure 12, on the rigid board 111, transmission signals from differential transmit buffers and amplifiers are transmitted via transmission lines 111a and 111b. Alternatively, differential transmit buffers and amplifiers can be directly mounted on the rigid board 111, and transmission is performed via transmission lines 111a and 111b. Here, since transmission lines 111a and 111b are designed to match the output impedance of coaxial connectors and amplifiers, they are often transmission lines with a characteristic impedance of 50Ω. Therefore, the distance between transmission lines 111a and 111b does not need to be close, and they can be designed independently. In other words, the distance between transmission lines 111a and 111b on the rigid board 111 is wider than the distance between transmission lines 101a and 101b on the flexible printed circuit board 107. Thus, when transmission lines are connected on the rigid board 111, the influence of connecting materials such as solder on the differential impedance is almost eliminated, thus reducing the impact on communication. Furthermore, since the transmission lines 111a and 111b and the transmission lines 101a and 101b are connected on the rigid substrate 111, the thickness of the connection part R2 will no longer affect the change in the gap with the receiving signal transmission device 200.

[0100] Thus, the structure of this embodiment can also suppress the impact on differential impedance.

[0101] In the embodiment described above, the ring-shaped housing 304 is arranged in the rotating part, the signal source 102 is the DAS 18, and the signal output from the signal source 102 is the X-ray signal collected by the DAS 18. However, the embodiment is not limited to this.

[0102] For example, the ring-shaped housing 304 is positioned in the fixed part. In this case, the signal source 102 is the console device 40 of the X-ray CT apparatus 1, and the signal output from the signal source 102 is a control signal transmitted by the console device 40 to the rotating part (rotating frame 13).

[0103] Alternatively, the ring-shaped housing 304 may consist of a first ring-shaped housing positioned in the rotating section and a second ring-shaped housing positioned in the fixed section. In this case, in the first ring-shaped housing, the signal source 102 is the DAS 18, and the signal output from the signal source 102 is the X-ray signal collected by the DAS 18. In the second ring-shaped housing, the signal source 102 is the console device 40 of the X-ray CT apparatus 1, and the signal output from the signal source 102 is the control signal to the rotating section transmitted by the console device 40.

[0104] Furthermore, although the above-described embodiment was explained using the case of application to an X-ray CT scanner as an example, it is not limited to an X-ray CT scanner, as long as it has a rotating part and a fixed part and requires high-capacity (multi-channel) communication. For example, the above-described embodiment can also be applied to network cameras, robot on-hand cameras, and the like.

[0105] According to at least one embodiment described above, low-frequency signals can be transmitted accurately without increasing the size of the device.

[0106] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0107] 100, 200, 300 signal transmission devices 101a, 101b transmission lines 107 Flexible Printed Circuit Boards 111 Rigid board 111a, 111b transmission lines 304 Ring-shaped housing 304B, 304C Support Members 304D opening

Claims

1. A signal transmission device that transmits a signal from one rotating part and one stationary part to the other by non-contact communication, A ring-shaped housing is installed on one of the rotating part and the fixed part, having a base body which is a ring-shaped metal member, a ring-shaped wall portion which constitutes a metal surface on the base body, and an opening formed by the wall portion and a region in which the base body is divided in the circumferential direction, A first substrate having a first transmission line arranged in the opening for transmitting a signal output from a signal source, and a reference potential conductor that provides a reference potential for the first transmission line, A second substrate having a second transmission line supported by the wall portion and bent radially at the opening, with the metal surface as the reference potential, Equipped with, The first transmission line and the second transmission line are electrically connected by the second substrate, which is bent radially at the opening, being placed on the first substrate. The first substrate has a region that contacts the metal surface. Signal transmission device.

2. The ring-shaped housing has multiple ring-shaped wall portions that constitute the metal surface, which are arranged at intervals in the axial direction. The wall portion has a divided region that is divided in the circumferential direction, The opening is formed by arranging a plurality of wall portions such that the divided region is at the same position in the circumferential direction. The second substrate is positioned along the circumferential direction by being supported by the radial end faces of two adjacent wall portions, and is further bent radially at the position where the wall portion is divided. The first substrate has a region that is sandwiched between two adjacent wall portions. The signal transmission device according to claim 1.

3. The first substrate has two main surfaces and two sides connecting the two main surfaces, The first transmission line is arranged on one of the two main surfaces. The reference potential conductor is positioned on the other main surface of the two main surfaces. In the aforementioned region, each of the two sides is in contact with each of the two adjacent wall portions. The signal transmission device according to claim 2.

4. The first transmission line and the second transmission line have a connection portion that is electrically connected on the first substrate. The signal transmission device according to claim 1.

5. The connecting portion is located in or near the region. The signal transmission device according to claim 4.

6. In the second transmission line, the line width of the transmission line formed in the circumferential direction of the ring-shaped housing is different from the line width of the transmission line formed at the connection portion. The signal transmission device according to claim 4.

7. The line width of the transmission line formed at the connection portion is set to be equal to the line width of the first transmission line. The signal transmission device according to claim 6.

8. The first substrate is arranged radially with respect to the ring-shaped housing. The signal transmission device according to claim 1.

9. The rotating unit comprises an X-ray tube, an X-ray detector for detecting X-rays irradiated from the X-ray tube, and a data acquisition device for collecting the X-ray signals detected by the X-ray detector. The fixed part has a rotation mechanism for rotating the rotating part. The signal transmission device according to claim 1.

10. The ring-shaped housing is arranged in the rotating part, The signal source is the data acquisition device, The aforementioned signal is the X-ray signal collected by the data acquisition device. The signal transmission device according to claim 9.

11. The ring-shaped housing is positioned on the fixed part, The aforementioned signal source is the console device of the X-ray CT apparatus. The aforementioned signal is a control signal transmitted by the console device to the rotating part. The signal transmission device according to claim 9.

12. A signal transmission device that transmits a signal from one rotating part and one stationary part to the other by non-contact communication, It comprises a first signal transmission device and a second signal transmission device, The first signal transmission device is A first ring-shaped housing, installed on the rotating part, has a base body which is a ring-shaped metal member, a ring-shaped wall portion which constitutes a metal surface on the base body, and an opening formed by the wall portion and the region in which the base body is divided in the circumferential direction, A first substrate having a first transmission line that is placed in the opening of the first ring-shaped housing and transmits X-ray signals collected by the data acquisition device, and a reference potential conductor that provides a reference potential for the first transmission line, A second substrate is supported by the wall portion of the first ring-shaped housing and has a second transmission line that is bent radially at the opening of the first ring-shaped housing, with the metal surface of the first ring-shaped housing as the reference potential, Equipped with, The first transmission line and the second transmission line are electrically connected by the second substrate, which is bent radially at the opening of the first ring-shaped housing, being placed on the first substrate. The first substrate has a region that contacts the metal surface of the first ring-shaped housing, The second signal transmission device is, A second ring-shaped housing, which is installed on the fixing part, has a base body that is a ring-shaped metal member, a ring-shaped wall portion that constitutes a metal surface on the base body, and an opening formed by the wall portion and the base body divided in the circumferential direction, A third substrate having a third transmission line that is positioned in the opening of the second ring-shaped housing and transmits control signals to the rotating part transmitted by the console device of the X-ray CT apparatus, and a reference potential conductor that provides a reference potential for the third transmission line, A fourth substrate is supported by the wall portion of the second ring-shaped housing and has a fourth transmission line that is bent radially at the opening of the second ring-shaped housing, with the metal surface of the second ring-shaped housing as the reference potential, Equipped with, The third transmission line and the fourth transmission line are electrically connected by the fourth substrate, which is bent radially at the opening of the second ring-shaped housing, being placed on the third substrate. The third substrate has a region that contacts the metal surface of the second ring-shaped housing. Signal transmission device.

13. A rotating unit having an X-ray tube, an X-ray detector for detecting X-rays irradiated from the X-ray tube, and a data acquisition device for collecting the X-ray signals detected by the X-ray detector, A fixed part having a rotation mechanism for rotating the aforementioned rotating part, A ring-shaped housing is installed on one of the rotating part and the fixed part, having a base body which is a ring-shaped metal member, a ring-shaped wall portion which constitutes a metal surface on the base body, and an opening formed by the wall portion and a region in which the base body is divided in the circumferential direction, A first substrate having a first transmission line arranged in the opening for transmitting a signal output from a signal source, and a reference potential conductor that provides a reference potential for the first transmission line, A second substrate having a second transmission line supported by the wall portion and bent radially at the opening, with the metal surface as the reference potential, Equipped with, The first transmission line and the second transmission line are electrically connected by the second substrate, which is bent radially at the opening, being placed on the first substrate. The first substrate has a region that contacts the metal surface. X-ray CT device.

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