JP2020017921A - Flexible waveguide, image transmission device having flexible waveguide, endoscope having flexible waveguide, and endoscope system - Google Patents

Abstract

To provide a flexible waveguide for transmitting radio waves with a frequency higher than the desired millimeter-wave (including submillimeter-wave) with smaller diameter while achieving both appropriate flexibility and excellent transmission characteristics.SOLUTION: A flexible waveguide 50 for conducting radio waves in the frequency band above 60 GHz and above millimeter and sub-millimeter waves, which includes: linear internal dielectrics 51 and 52 having a uniform dielectric constant in the longitudinal direction and a uniform cross-section in the longitudinal direction; a flexible outer conductor 53 disposed at a position covering the outer periphery of the dielectric 52; and a flexible substrate 40 arranged to be wound around the outer surface of the outer conductor 53.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a waveguide used for high-frequency radio wave signal transmission, more specifically, a flexible waveguide suitable for radio wave transmission in a millimeter wave or a submillimeter wave band or more, and an image transmission device having a flexible waveguide. , An endoscope having a flexible waveguide and an endoscope system.

  2. Description of the Related Art In recent years, a communication environment having a communication speed exceeding 1 Gbps has become widespread in ordinary homes by a technology such as so-called FTTH (Fiber To The Home). In addition, terminals having high processing capabilities such as smartphones have become widespread, and available communication technologies and information processing speeds, that is, “hard performance” have been significantly improved.

  In addition, the use of high-definition / large-capacity video typified by 4K / 8K images that exceed the so-called FHD (Full High Definition) and the expansion of information access via the Internet have led to the quality of information available to individuals and companies. And the amount, that is, "software use" is also expanding dramatically.

  These have greatly contributed to the creation of new methods and added value, such as the development of AI (artificial intelligence) by big data analysis, which has attracted particular attention in recent years, and AI by deep learning (deep learning).

  As described above, the improvement of “hardware performance” and the expansion of “use of software” are two wheels, and the technology in recent years has been remarkably developed, and new added value has been born. As a result, the performance required of information and communication technology at the present time is much higher than before. Focusing on the signal transmission line among the technical elements required for information communication, it can be seen that the performance required in this field is significantly higher.

  Here, at present, “electrical interconnection (connection by a metal wire) is mainly used in a region where the transmission distance is short and the transmission speed is low”, while “an optical interconnection is used in a region where the transmission distance is long and the transmission speed is high”. Connection (optical communication, that is, connection using an optical fiber) is mainly used. "

  That is, for example, the electrical interconnection at about several meters has a transmission limit of about 2.5 Gbps, and if it exceeds this, it can be said that optical interconnection (optical communication) is an effective means.

  As described above, in a region where the transmission distance is long and the transmission speed is high, optical communication is considered to be an effective means, but it is known that optical communication has a problem related to the reliability of signal transmission. That is, since a communication optical fiber is generally composed of a single line mainly composed of quartz glass, the optical fiber serving as a signal transmission line may be unexpectedly cut due to an unintended impact or the like. There is a fear.

  Similarly, it is also known that optical communication has a problem related to connectivity. That is, since a communication optical fiber that is usually used has a core wire called a core for transmitting an optical signal having a diameter of only about 50 μm or less, this connection requires extremely high positioning accuracy on the order of μm, and also requires dust. Connection may not be possible due to the influence of

  By the way, the electrical interconnection (connection by metal wire) generally consists of a bundle of a plurality of thin wires, and even when cut, the thin wires gradually break, so the communication performance gradually deteriorates, By knowing the deterioration of the communication performance, it is possible to take measures such as repair in advance. Also, the connection of the line is usually required to have an accuracy of the order of 0.1 mm, and there is no particular difficulty such that the influence of dust is easily eliminated.

  That is, due to the above-mentioned problems, it is considered that optical communication is not a substitute for electrical interconnection especially in applications where high reliability is required for communication or in applications where connection between lines is required in use.

  In view of the above-described circumstances, the present inventor has proposed a method of achieving a communication speed of 5 Gbps or more with a length of about several centimeters to 5 meters or less, and a transmission speed which is an issue of a signal transmission method using a lead wire. Japanese Patent Application No. 2015-131913 has proposed a technique using a radio wave and a waveguide as a new signal transmission method that overcomes the limitations and also overcomes the problems of the signal transmission method using an optical fiber.

  That is, according to the flexible waveguide for transmitting radio waves having a frequency equal to or higher than a millimeter wave (including a submillimeter wave), which can be applied to communication having a length from the size of an electric board to the length of a general wire, It is possible to realize a communication line capable of high-speed communication on the order of several tens of Gbps, which is difficult to realize by electric interconnection, while overcoming the problems (reliability problems, problems related to connection).

  In general, it is difficult to achieve flexibility in a waveguide that transmits radio waves having frequencies equal to or higher than millimeter waves (including submillimeter waves). On the other hand, a technique for realizing such a flexible waveguide is also known.

  For example, in the method described in Japanese Patent No. 4724849 (Patent Document 1), the flexibility of the waveguide is increased by using an insulating thread as the internal dielectric, and the type of the thread of the internal dielectric is increased. Is intended to stabilize the transmission characteristics by generating a distribution in the dielectric constant.

  Further, in the technique described in Japanese Patent Application Laid-Open No. 8-195605 (Patent Literature 2), the outer conductor is formed by attaching a thin conductor without gaps to achieve both flexibility and reduction of transmission loss. Is what you do.

  Further, Japanese Patent Application Laid-Open No. 2015-185858 (Patent Document 3) discloses that a required number of flat foil yarns having a flat cross-sectional shape are wound around a dielectric material in a so-called braided shape to thereby reduce the transmission loss and reduce the transmission loss. Techniques for forming a conductive waveguide are described.

  Furthermore, Japanese Patent Application Laid-Open No. 2006-127429 (Patent Document 4) describes a technique of forming a waveguide that secures flexibility by winding a shield member capable of providing shielding properties and bending resistance. Have been.

Patent No. 4724849 JP-A-8-195605 JP 2015-185858 A JP-A-2006-127429

  However, the flexible waveguides described in JP-A-2005-185858 (Patent Document 3) and JP-A-2006-127429 (Patent Document 4) transmit relatively high-speed signals such as image transmission. Although effective in terms of handling, a power supply line that supplies a predetermined power such as a DC voltage to an electrical component disposed at one end of the waveguide, or a relatively low-speed power source that controls driving of the electrical component Cables for handling signals such as drive control signal lines had to be prepared separately.

  When the above-described flexible waveguide is applied to, for example, a transmission line where reduction in diameter is desired, the presence of the above-described power supply line and drive control signal line causes the increase in diameter, and a plurality of wires are electrically connected. It has to be joined to a unit such as a part, which requires time and effort.

  The present invention has been made in view of the above circumstances, and achieves both appropriate flexibility and excellent transmission characteristics in a waveguide for transmitting a radio wave having a frequency equal to or higher than a desired millimeter wave (including a submillimeter wave). And a flexible waveguide having a smaller diameter, an image transmission device having the flexible waveguide, an endoscope having the flexible waveguide, and an endoscope system. is there.

  A flexible waveguide according to one embodiment of the present invention includes a linear dielectric having a uniform dielectric constant in the longitudinal direction and the same cross-section in the longitudinal direction, and a position covering the outer periphery of the dielectric. Provided, an outer conductor formed of a flexible tube, and a flexible waveguide that conducts radio waves in a frequency band of millimeter waves or sub-millimeter waves or more near 60 GHz or more, A flexible substrate disposed to be wound around the outer surface of the outer conductor.

  An image transmission device according to one embodiment of the present invention is an image transmission device including the flexible waveguide, wherein the flexible waveguide transmits a predetermined image signal.

  An endoscope according to one embodiment of the present invention is an endoscope including the flexible waveguide, wherein the flexible waveguide transmits a predetermined image signal.

  An endoscope system according to one embodiment of the present invention includes the endoscope, and an image processing unit that performs predetermined image processing on a predetermined image signal transmitted by the flexible waveguide. .

  ADVANTAGE OF THE INVENTION According to this invention, while realizing appropriate flexibility and excellent transmission characteristics in a waveguide for transmitting radio waves of a frequency higher than a desired millimeter wave (including a submillimeter wave), a smaller diameter is realized. A flexible waveguide, an image transmission device having the flexible waveguide, an endoscope having the flexible waveguide, and an endoscope system can be provided.

FIG. 1 is a perspective view showing a schematic configuration of an endoscope system having a flexible waveguide according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a functional configuration of a main part of the endoscope system according to the first embodiment. FIG. 3 is an essential part enlarged perspective view showing the structures of the flexible waveguide and the imaging unit according to the first embodiment. FIG. 4 is an enlarged perspective view of a main part of the structure of the flexible waveguide and the imaging unit according to the first embodiment in a partial cross section. FIG. 5 is an enlarged perspective view of a main part showing a state in which a flexible substrate including a power supply line and the like is provided on the outer surface of the flexible waveguide according to the first embodiment. FIG. 6 is an explanatory diagram illustrating a state near a connection portion between the flexible substrate disposed on the outer surface of the flexible waveguide according to the first embodiment and the imaging unit. FIG. 7 is an explanatory diagram showing a state in which a flexible substrate is periodically wound on the outer surface of the flexible waveguide according to the first embodiment, and a fixing position with an adhesive. FIG. 8 is an explanatory diagram showing a bonding state near a connection portion between the flexible substrate provided on the outer surface of the flexible waveguide according to the first embodiment and the imaging unit. FIG. 9 is a perspective view of a main part showing the configuration of the flexible waveguide according to the first embodiment. FIG. 10 is an enlarged perspective view of a main part showing a second dielectric in the flexible waveguide of the first embodiment. FIG. 11 is an enlarged sectional view of a main part showing a cross section in a direction perpendicular to the longitudinal direction of the flexible waveguide (including the flexible substrate) of the first embodiment. FIG. 12 is an enlarged sectional view of a main part showing the configuration of an outer conductor and an inner dielectric formed by braiding flat foil yarns in a braided shape in the flexible waveguide of the first embodiment. FIG. 13 is an external view showing the external appearance of an outer conductor formed by braiding flat foil yarns into a braid in the flexible waveguide of the first embodiment. FIG. 14 is a cross-sectional view of a main part illustrating a configuration of an external conductor in the flexible waveguide according to the first embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, each embodiment shown below demonstrates the endoscope system which has the flexible waveguide of each embodiment as an example.

  The embodiments do not limit the present invention. Further, in the description of the drawings, the same portions are denoted by the same reference numerals. Furthermore, the drawings are schematic, and it should be noted that the relationship between the thickness and width of each member, the ratio of each member, and the like are different from reality. In addition, the drawings include portions having different dimensions and ratios.

<First embodiment>
FIG. 1 is a perspective view showing a schematic configuration of an endoscope system having a flexible waveguide according to a first embodiment of the present invention, and FIG. 2 is an endoscope according to the first embodiment. FIG. 2 is a block diagram illustrating a functional configuration of a main part of the mirror system.

  As shown in FIG. 1, the endoscope system 1 is a so-called upper digestive tract endoscope system, which captures an in-vivo image of a subject P by inserting a distal end portion into a body cavity of a subject P. An endoscope 2 including an imaging unit that outputs an image signal of a subject image, an endoscope 2 including an image processing unit that performs predetermined image processing on an image signal output from the imaging unit in the endoscope 2. A video processor 3 that controls the overall operation of the system 1, a light source device 4 that generates illumination light to be emitted from the end of the endoscope 2, and an image processed by the video processor 3. And a display device 5 that performs the operation.

  The endoscope 2 is provided with the imaging section at the distal end thereof, and is mainly composed of an elongated section having flexibility. The endoscope 2 is connected to the base end side of the insertion section 6 to input various operation signals. The operation unit 7 includes a universal cord 8 extending from the operation unit 7 toward the base end and connected to the video processor 3 and the light source device 4.

  Here, the endoscope 2 is provided between the imaging unit provided at the distal end of the insertion unit 6 and the image processing unit of the video processor 3 from the imaging unit of the insertion unit 6 to the insertion unit 6 and the operation unit 7. And a signal transmission path extending to the image processing unit of the video processor 3 via the inside of each of the universal cords 8 and for transmitting image signals and the like from the imaging unit.

  The endoscope system according to the present embodiment is characterized in that the signal transmission path is configured by a waveguide that passes a millimeter wave or a submillimeter wave (hereinafter, may be referred to as a millimeter wave in some cases). (The “waveguide” will be described later in detail).

  Returning to FIG. 1, the insertion section 6 is provided at a distal end portion, and includes a rigid distal end portion 10 including an imaging element 22 and the like constituting the imaging section, and a proximal end side of the rigid distal end portion 10. The bending section 9 includes a plurality of bending pieces. The bending section 9 includes a plurality of bending pieces. The bending section 9 is connected to a base end of the bending section 9.

  As shown in FIG. 2, in the present embodiment, the distal end rigid portion 10 disposed at the forefront of the insertion section 6 includes an imaging optical system 21 for receiving an object image and a rear portion of the imaging optical system 21. And an imaging unit 20 including an imaging element 22 and the like that captures an image of a subject and outputs a predetermined image signal by photoelectric conversion.

  The image pickup unit 20 is provided at an image forming position of the image pickup optical system 21 and receives the light collected by the image pickup optical system 21 and photoelectrically converts the light into an electric signal. A driver IC 23 disposed on the end side for driving the image pickup device 22 and performing predetermined processing on an image pickup signal output from the image pickup device 22; A transmission / reception antenna 27 (detailed later) for transmitting and receiving signals via a waveguide (detailed later) 50.

  In the present embodiment, the image sensor 22 is a CMOS (Complementary Metal Oxide Semiconductor) image sensor and employs an image sensor having a pixel number of 2,000,000 pixels or more, which is a pixel number equivalent to so-called Full HD. I do.

  The driver IC 23 includes an analog front end (AFE) 24 that performs noise removal and A / D conversion on an electric signal output from the image sensor 22 and a drive timing of the image sensor 22 and various signal processing pulses in the AFE 24 and the like. In order to connect a generated timing generator (TG) 25 and the transmitting / receiving antenna 27 to transmit / receive a digital signal output by the AFE 24 to / from the image processing unit in the video processor 3 via the flexible waveguide 50. , And a control unit (not shown) for controlling the operation of the image sensor 22.

  The transmission / reception circuit 26 is a millimeter-wave / sub-millimeter-wave communication circuit formed by a so-called MMIC (monolithic microwave integrated circuit).

  In the present embodiment, all the circuits such as the analog front end AFE 24, the timing generator TG 25, and the transmission / reception circuit 26 are formed by a silicon CMOS process, and the driver IC 23 is sufficiently miniaturized.

  The imaging element 22 and the driver IC 23 are connected via a ceramic substrate 28, and a plurality of passive components such as a capacitor 29 are mounted on the ceramic substrate 28 (see FIG. 3 and the like).

  On the other hand, the video processor 3 includes an image signal processing circuit 31 as the image processing unit that performs predetermined image processing on an image signal output from the imaging unit 20 in the endoscope 2, A power supply circuit 32 for generating a power supply for supplying power to the element 22 and the like, and transmission and reception for transmitting and receiving predetermined signals to and from the imaging unit 20 in the endoscope 2 via the flexible waveguide 50 It includes a circuit 33 and a transmission / reception antenna 34 connected to the transmission / reception circuit 33.

  The image signal processing circuit 31 generates a control signal (for example, a clock signal, a synchronization signal, and the like) for controlling the image sensor 22 and the driver IC 23, and sends out the control signal to the image sensor 22 and the driver IC 23.

  The transmission / reception circuit 33 in the video processor 3 is also formed of a so-called MMIC (monolithic microwave integrated circuit), similarly to the transmission / reception circuit 26.

  As shown in FIG. 2, the flexible waveguide 50 as a signal transmission path is internally provided in the insertion section 6, the operation section 7, and the universal cord 8 of the endoscope 2 as described above. However, in this embodiment, on the outer surface of the flexible waveguide 50, a flexible substrate 40 provided with various signal lines is provided.

  That is, as shown in FIGS. 2 and 5, a flexible substrate 40 is disposed on the outer surface of the flexible waveguide 50 in the present embodiment. A control signal line 41 transmitting various control signals supplied from the image signal processing circuit 31 in the video processor 3, a power supply line 42 transmitting power supplied from the power supply circuit 32, and a ground line (GND line) 43 are respectively provided. Installed internally. The flexible substrate 40 will be described later in detail.

  Then, a predetermined control signal (for example, a clock signal, a synchronization signal, or the like) is supplied to the imaging element 22 of the endoscope 2 and the respective circuits of the driver IC 23 via the control signal line 41. I have.

  Similarly, a video signal is supplied to the imaging element 22 of the endoscope 2 and the respective circuits of the driver IC 23 via the power supply line 42 and the ground line (GND line) 43 provided inside the flexible substrate 40. Power is supplied from a power supply circuit 32 of the processor 3.

<Flexible waveguide, transmission / reception circuit, and imaging unit>
Next, the waveguide (flexible waveguide) and the transmission / reception circuit in the endoscope system according to the present embodiment, and their peripheral circuits (such as an imaging unit) will be described.

  The present invention relates to a flexible waveguide used in a millimeter wave region (including a submillimeter wave) including a dielectric mixed material which appropriately satisfies three conditions of a high dielectric constant, a small dielectric loss tangent, and an appropriate flexibility. Provided are a tube, an image transmission device having the flexible waveguide, an endoscope having the flexible waveguide, and an endoscope system.

  In addition, the present invention provides a millimeter signal instead of a signal transmission method using a lead wire and an optical fiber, which has been conventionally used as a signal transmission method for connecting an imaging unit in the endoscope and an image processing unit in a video processor. A signal transmission method using a waveguide (flexible waveguide) for passing a wave or a submillimeter wave (a radio wave having a frequency of about 30 to 600 GHz) is also newly proposed.

  In the present embodiment, the millimeter wave and the submillimeter wave refer to radio waves having a wavelength in the order of millimeters to submillimeters (about 0.5 to 10 mm).

  As shown in FIG. 2, the imaging unit 20 is provided behind the imaging optical system 21 that receives the subject image at the distal end rigid portion 10 provided at the distal end of the insertion section 6. In addition, as described above, the imaging unit 20 includes the imaging element 22 that captures the subject image and outputs a predetermined image signal by photoelectric conversion, and the like. Thus, a waveguide (flexible waveguide) 50 (in this embodiment, the flexible substrate 40 is provided on the flexible waveguide 50) is extended.

  Further, as described above, the image pickup unit 20 is provided on the image pickup element 22 that receives the light condensed by the image pickup optical system 21 and photoelectrically converts the light into an electric signal, and is disposed at a base end near the image pickup element 22. A driver IC 23 that drives the image sensor 22 and performs predetermined processing on an image signal output from the image sensor 22, and is provided on the base end side of the driver IC 23 and transmits and receives signals via a flexible waveguide 50. And a transmission / reception antenna 27 for communication.

  As described above, the driver IC 23 has the analog front end (AFE) 24, the timing generator (TG) 25, the transmission / reception circuit 26, a control unit (not shown), and the like. The driver IC 23 is connected to the imaging device 22 via the ceramic substrate 28. It has become so.

<Configuration of Flexible Waveguide and Flexible Substrate>
FIG. 3 is an enlarged perspective view of a main part showing the structure of the flexible waveguide and the imaging unit according to the first embodiment, and FIG. 4 is a flexible waveguide according to the first embodiment. FIG. 2 is an enlarged perspective view of a main part showing a structure of the imaging unit in a partial cross section. FIG. 5 is an enlarged perspective view of a main part showing a state in which a flexible substrate including a power supply line and the like is provided on the outer surface of the flexible waveguide according to the first embodiment. 3 and 4, the flexible substrate 40 is not shown.

  As shown in FIG. 3, FIG. 4, and FIG. 5, the base end of the driver IC 23 has the transmitting / receiving antenna 27 integrated with the package of the driver IC 23 interposed therebetween so as to pass the millimeter wave or the submillimeter wave. The distal end of the flexible waveguide 50 and the distal end of the flexible substrate 40 are connected.

  The flexible waveguide 50 (hereinafter, also referred to as a waveguide 50) has flexibility, and after the distal end side is connected to the driver IC 23 disposed on the rigid distal end portion 10, the insertion portion 6 To be extended toward the base end side.

  More specifically, the flexible waveguide 50 has a more proximal end side than the driver IC 23 in the insertion portion 6, that is, a proximal end portion of the distal end rigid portion 10 from a place where the driver IC 23 is disposed. After passing through the inside of the insertion portion 6 including the bending portion 9 and the flexible tube portion on the side, the inside of the operation portion 7 and the inside of the universal cord 8 are inserted to reach the video processor 3. It has become.

  The base end side of the flexible waveguide 50 may be connected to the video processor 3 through conversion in a connector provided at one end of the universal cord 8.

  The flexible waveguide 50 is a signal transmission line connecting the imaging unit 20 and the image processing unit (image processing circuit 31) in the video processor 3, and at least a part of the flexible waveguide 50 propagates a millimeter wave or a submillimeter wave. It is a waveguide.

<Inner dielectric and outer conductor in flexible waveguide>
Here, the internal dielectric and the external conductor in the flexible waveguide 50 in the present embodiment will be described in detail.

  FIG. 9 is a perspective view of a main part of the flexible waveguide according to the first embodiment of the present invention, in which a flexible substrate is omitted.

  The flexible waveguide according to the present embodiment includes a dielectric material that appropriately satisfies three conditions of high dielectric constant, small dielectric loss tangent, and appropriate flexibility, and has a millimeter wave region (including a submillimeter wave). , And is characterized by being constituted by a waveguide through which a millimeter wave or a submillimeter wave (hereinafter, sometimes referred to as a millimeter wave in some cases) passes.

  In the present embodiment, the millimeter wave and the submillimeter wave refer to radio waves having a wavelength in the order of millimeters to submillimeters (about 0.5 to 10 mm).

  As shown in FIG. 9, the flexible waveguide 50 according to the first embodiment has linear flexibility in which the dielectric constant is uniform in the longitudinal direction and the cross section has the same shape in the longitudinal direction. It has an internal dielectric (a first dielectric 51 and a second dielectric 52) and an external conductor 53 disposed at a position covering the outer periphery of the internal dielectric. In FIG. 9, the flexible substrate 40 is omitted.

  In the present embodiment, “uniform dielectric constant” means that the electric wave (millimeter wave or submillimeter wave) propagating inside the waveguide is uniform when viewed in a wavelength order. That is, since the permittivity distribution due to the structure having a dimension different from the wavelength order by one to two digits or more does not affect the radio wave propagating inside the waveguide, the permittivity including this in the present embodiment includes the permittivity. Expressed as uniform.

<Structure of internal dielectric>
FIG. 10 is an enlarged perspective view of a main part showing a second dielectric in the flexible waveguide according to the first embodiment, and FIG. 11 is a flexible waveguide and a flexible waveguide according to the first embodiment. FIG. 5 is an enlarged cross-sectional view of a main part showing a cross section in a direction perpendicular to the longitudinal direction of the flexible substrate.

  In the first embodiment, the internal dielectric includes a first dielectric 51 positioned relatively inside in a cross section perpendicular to the longitudinal direction, and a first dielectric 51 positioned in a cross section perpendicular to the longitudinal direction. The first dielectric 51 is located outside the first dielectric 51 (and is disposed so as to cover the entire circumference of the outer periphery of the first dielectric 51) and has a lower dielectric constant than the first dielectric 51. 2 dielectrics 52.

  Further, in the present embodiment, as shown in FIG. 9, the internal dielectric is formed of crystal powder inside the space of the second dielectric 52 having a space having a continuous tubular shape at the center in the longitudinal direction. The first dielectric 51 is filled.

In the present embodiment, the crystal powder in the first dielectric 51 is a high-purity α-Al ₂ O ₃ crystal powder (in this embodiment, high-purity alumina AA-18 manufactured by Sumitomo Chemical Co., Ltd. = 99.99% or more). The high-purity α-Al ₂ O ₃ crystal powder has, for example, a substantially spherical shape with an average diameter of about 18 μm.

  Note that, in FIG. 9, the first dielectric 51 is drawn as a rod-like solid shape for convenience, but as described above, the first dielectric 51 is made of alumina crystal powder, By filling the inside of the tube-shaped space at 52, the shape is maintained. In FIG. 9, the flexible substrate 40 is omitted.

  On the other hand, the second dielectric 52 is formed of expanded PTFE (e-PTFE), and has a space having a continuous tubular shape at the center in the longitudinal direction as shown in FIG. In the second dielectric 52, continuous pores are formed on the inner surface of the tubular shape.

Here, the size (diameter) of the high-purity α-Al ₂ O ₃ crystal in the first dielectric 51 is larger than the size of the continuous pores in the second dielectric 52, that is, α-Al ₂ O ₃ crystals cannot pass through the continuous pores.

<Structure of external conductor>
FIG. 12 is a main part enlarged cross-sectional view showing a configuration of an outer conductor and an inner dielectric formed by braiding flat foil yarns in a braided shape in the flexible waveguide of the first embodiment, and FIG. FIG. 2 is an external view showing an external conductor formed by braiding flat foil threads in a braided shape in the flexible waveguide of the first embodiment. FIG. 14 is a cross-sectional view of a main part illustrating a configuration of an external conductor in the flexible waveguide according to the first embodiment.

  In this embodiment, the outer conductor 53 is disposed at a position covering the outer periphery of the inner dielectric (the first dielectric 51 and the second dielectric 52) as shown in FIGS. 9, 11, 12, and the like. It is configured as a flexible cylindrical metal layer. Specifically, the outer conductor 53 is constituted by a plurality of band-shaped flat foil threads.

  As shown in FIG. 14, this band-shaped flat foil thread has a rectangular cross section perpendicular to the stretching direction, and has a base layer 55 containing a non-metallic substance such as a resin and a metal foil 56 containing a metallic substance. It is configured to have. More specifically, the flat foil yarn adopts a resin film (for example, PET) having a thickness of 25 μm as the base layer 55, and adopts a copper foil having a thickness of 9 μm as the metal foil 56 and has a width of 0.2 mm. Is formed.

  Further, the outer conductor 53 is formed by assembling a plurality of (for example, 32) flat foil threads into a cylindrical braid as shown in FIGS. Specifically, on the outer peripheral surface of the second dielectric 52, which is the outer dielectric of the inner dielectric, the metal foil 56 is arranged and wound on the side in contact with the second dielectric 52. It extends and is knitted such that the flat foil yarns form a braided form (see an enlarged view in FIG. 12).

The outer conductor 53 includes the predetermined metal layer (metal foil 56) as described above, and the conductivity of the metal foil 56 is set to 59 × 10 ⁶ S / m equivalent to pure copper. Although the conductivity is uniquely determined here, the conductivity of the metal layer portion in the present invention is not limited to this, and in the embodiment, it is preferable to use a metal layer having good conductivity.

  As described above, in the present embodiment, the flat foil yarn serving as the outer conductor 53 is configured such that the metal foil 56 is disposed on the side in contact with the second dielectric 52 and the resin film 55 is provided on the outer side. The present invention is not limited to this, and may be configured in another form including a metal layer (for example, only by a metal layer).

  Further, as described above, when a plurality of flat foil yarns serving as the outer conductors 53 are wound around the outer periphery of the second dielectric 52 at an angle of, for example, 45 degrees and woven into a braided shape, a gap between the yarns Thus, a hole referred to as a so-called "lace hole" is generated. As shown in the enlarged view of FIG.

  In the string hole 54, the surface of the lower second dielectric 52 is exposed in the "hole" portion. As described above, in the flexible waveguide 50 of the present embodiment, the external conductor 53 is formed such that the ratio of the metal portion periodically changes in the longitudinal direction (propagation direction) of the waveguide. In other words, in the flexible waveguide 50 of the present embodiment, the outer conductor 53 has a periodic shape change in the longitudinal direction, and the resistance (impedance) distribution of the outer conductor is predetermined in the propagation direction. With a periodicity of.

  The cross-sectional shapes of the first dielectric 51 and the second dielectric 52 perpendicular to the longitudinal direction are as follows.

As shown in FIG. 11, the second dielectric 52 has a cylindrical shape that covers the outer peripheral portion of the first dielectric 51, and the center of the first dielectric 51 is disposed inside the second dielectric 52.
The inner circumference has a major axis a = 1.66 mm and a minor axis b = 0.83 mm.
The outer periphery has a diameter r = 2.26 mm
Is set to

Further, the outer conductor 53 is disposed so as to closely cover the outer peripheral portion of the second dielectric 52, the inner peripheral surface thereof is flat, and the conductivity is 59 × 10 ⁶ S / m equivalent to pure copper. Is set.

  In FIG. 11 and the like, the outer conductor 53 is represented as having a predetermined thickness. However, as described above, the drawings are schematic, and the relationship between the thickness and width of each member, Is different from reality, that is, the outer conductor 53 is actually formed of a sufficiently thin metal foil 56.

  As described above, the first dielectric body 51 in the present embodiment is configured to easily maintain the cross-sectional shape, and thereby has an effect that the transmission mode of a radio wave transmitted inside the dielectric body can be stabilized. .

  Further, as described above, the flexible waveguide 50 is bent by an external force applied from the outside because the stable cross-sectional shape in the longitudinal direction is extended in the first dielectric 51. Even if it is performed, an increase in transmission loss due to the bending is suppressed, and as a result, the effect of stabilizing the amount of transmission loss is exhibited.

  On the other hand, as described above, in the present embodiment, the second dielectric 52 is disposed so as to cover the entire outer periphery of the first dielectric 51, and the second dielectric 52 and the metal layer Is disposed in a region sandwiched between the external conductor 53 and the external conductor 53.

  Here, as described above, the second dielectric 52 has a lower dielectric constant than the first dielectric 51. That is, since the dielectric constant of the first dielectric 51 is higher than the dielectric constant of the second dielectric 52, the second dielectric 52 covers the entire circumference of the outer peripheral portion of the first dielectric 51. Since it is disposed so as to cover, the energy of the electromagnetic wave transmitted in the flexible waveguide 50 can be confined in the first dielectric 51.

  As a result, in the flexible waveguide 50 of the present embodiment, it is possible to suppress the occurrence of transmission loss due to the outer conductor 53 which is a metal layer.

<Structure of flexible substrate>
FIG. 5 is an enlarged perspective view of a main part showing a state in which a flexible substrate including a power supply line and the like is provided on the outer surface of the flexible waveguide according to the first embodiment. FIG. 6 is an explanatory diagram showing a state near a connecting portion between the flexible substrate disposed on the outer surface of the flexible waveguide according to the first embodiment and the imaging unit.

  As shown in FIG. 5, in the present embodiment, a flexible substrate 40 having various signal lines provided therein is disposed on the outer surface of the flexible waveguide 50.

  The flexible substrate 40 is formed of a flexible substrate or a stretchable substrate having a thickness of about 0.2 mm, in which a control signal line 41, a power supply line 42, and a ground line (GND line) 43 are provided. The flexible substrate 40 is spirally wound around the outer surface of the outer conductor 53 of the flexible waveguide 50 as shown in FIG. It is extended toward.

  As described above, the flexible substrate 40 is made of a flexible substrate or a stretchable substrate having a thickness of about 0.2 mm, but is made of a material having sufficient flexibility. .

  The flexible substrate 40 is spirally wound around the outer surface of the flexible waveguide 50 and extended so as not to affect the flexibility of the flexible waveguide 50. It is supposed to be.

  In the present embodiment, as described above, the outer conductor 53 is formed by assembling a plurality (for example, 32) of flat foil threads into a cylindrical braid as shown in FIG. Is spirally wound around the outer surface of the outer conductor 53 knitted in a cylindrical braid so as not to affect the displacement of the outer conductor 53.

<Bending of flexible substrate 40>
5 and 6, a connector terminal 44 is provided at one end of the flexible substrate 40 and is connected to the ceramic substrate 28 of the imaging unit 20.

  Here, as described above, the flexible substrate 40 is spirally wound around the outer surface of the outer conductor 53 of the flexible waveguide 50 and is extended therefrom. 5 and 6, the connector terminal 44 provided on the distal end side of the bent portion is connected to the ceramic substrate 28, as shown in FIGS. ing.

In the present embodiment, the flexible substrate 40 is bent such that the long axis direction of the flexible waveguide 50 and the side surface of the connector terminal 44 are parallel. Specifically, as shown in FIG. 6, the angle at which the flexible substrate 40 is spirally wound around the external conductor 53 (the angle at which the flexible substrate 40 is wound) is α, and the flexible substrate 40 is bent. Assuming that the angle (bending angle of the flexible substrate 40) is β,
Bending angle β = winding angle α / 2
The flexible substrate 40 is bent so as to have the following relationship.

Further, when the flexible substrate 40 is bent, the end of the back surface and the end of the front surface of the flexible substrate 40 overlap. When the angle of the overlapping portion is γ,
γ = winding angle α
The flexible substrate 40 may be bent such that

  By bending the flexible substrate 40 in this manner, the mounting direction between the flexible waveguide 50 and the connector of the waveguide (not shown) and the connection between the flexible substrate 40 and the connector of the flexible substrate (not shown) are changed. Since the mounting direction is the same, the flexible substrate 40 and the flexible waveguide 50 can be connected with a small volume, for example, at the end of the endoscope.

  Further, since the connection portion between the flexible waveguide 50 and the flexible substrate 40 is parallel, the stress applied to the flexible substrate 40 and the flexible waveguide 50 after the attachment is the same, and the connector After connection, stress is not applied to one of them, and the cause of a connection failure such as disconnection can be eliminated.

<Periodic Arrangement and Fixation of Flexible Substrate 40>
FIG. 7 is an explanatory view showing a state in which the flexible substrate is periodically wound on the outer surface of the flexible waveguide according to the first embodiment and a fixing position by an adhesive, and FIG. FIG. 4 is an explanatory diagram illustrating an adhesion state near a connection portion between a flexible substrate disposed on an outer surface of the flexible waveguide according to the first embodiment and an imaging unit.

  As shown in FIG. 7, the flexible substrate 40 is spirally wound on the outer surface of the outer conductor 53 of the flexible waveguide 50 while maintaining a periodic pitch.

  Here, the flexible substrate 40 itself is made of a material having sufficient flexibility as described above, but also has a resilience, so even if it is wound around the flexible waveguide 50. If not fixed to the flexible waveguide 50, it will be separated from the flexible waveguide 50.

  In view of such circumstances, the flexible substrate 40 of the present embodiment does not affect the displacement of the flexible waveguide 50 (the outer conductor 53) to be wound, as shown in FIG. It is fixed to the external conductor 53 by an adhesive 61 at regular intervals in the longitudinal direction.

  On the other hand, the flexible substrate 40 requires a certain degree of freedom because the connector terminal 44 provided at one end thereof must be connected to the terminal portion of the ceramic substrate 28 in the imaging unit.

  In view of such circumstances, as shown in FIG. 8, the flexible substrate 40 of the present embodiment is fixed to the external conductor 53 with an adhesive 61 on the base end side of the bent portion of the flexible substrate 40, and The distal end side of the portion is formed to be a free end.

  Thus, when connecting the flexible board 40 to a connector (not shown), the flexible board 40 itself has a degree of freedom, so that it can be easily connected.

  On the other hand, a control signal line 41 provided inside the flexible substrate 40 extends from the image signal processing circuit 31 of the video processor 3 and, for example, a predetermined control signal (for example, clock signal) for supplying to the image sensor 22. Signal, synchronization signal, etc.). Then, the above-described predetermined control signals (for example, a clock signal, a synchronization signal, and the like) are supplied to the imaging element 22 in the endoscope 2 and the respective circuits in the driver IC 23 via the control signal line 41. Has become.

  It should be noted that the above-described control signals (clock signals and synchronization signals) are relatively slow signals as compared with high-speed image signals transmitted in the flexible waveguide 50 by radio waves.

  Further, a power supply line 42 and a ground line (GND line) 43 provided inside the flexible substrate 40 extend from the power supply circuit 32 of the video processor 3 and are disposed on the distal end side of the flexible waveguide 50. It is connected to the provided image sensor 22 and driver IC 23. Then, power is supplied from the power supply circuit 32 of the video processor 3 to the imaging device 22 and the circuits in the driver IC 23 in the endoscope 2 via the power supply line 42 and the ground line (GND line) 43. It has become.

The control signal line 41, the power supply line 42, and the ground line (GND line) 43 on the flexible substrate 40 are connected to a video processor via predetermined connector terminals (not shown in FIG. 5) at their base ends. 3 image signal processing circuits 31.
On the other hand, the distal ends of the control signal line 41, the power supply line 42, and the ground line (GND line) 43 are connected to terminal portions of the ceramic substrate 28 by predetermined connector terminals 44, as shown in FIG.

  As described above, the flexible waveguide 50 according to the present embodiment includes a flexible substrate with a thickness of about 0.2 mm in which the control signal line 41, the power supply line 42, and the ground line (GND line) 43 are provided. Since the flexible substrate 40 constituted by a stretchable substrate is helically wound around the outer surface of the outer conductor 53 of the flexible waveguide 50, the flexible substrate 50 can be used. The diameter of the flexible waveguide 50 can be reduced without affecting the flexibility.

  Further, the flexible waveguide 50 on which the flexible substrate 40 of the present embodiment is disposed is configured such that cables such as a control signal line 41, a power supply line 42, and a ground line (GND line) 43 are separately joined to the imaging unit 20. Since it is possible to save time and effort, the number of steps can be greatly reduced.

  In the above-described embodiment, the flexible substrate 40 is disposed so as to be wound around the outer surface of the flexible waveguide 50. However, in the endoscope system 1 including the flexible waveguide 50, For example, even for an endoscope system having a transmission path using an optical fiber, the flexible substrate 40 may be disposed so as to be wound around the outer surface of the optical fiber.

<Second embodiment>
Next, a second embodiment of the present invention will be described.

  In the first embodiment described above, the flexible waveguide as described above is applied to an endoscope. In the second embodiment, the flexible waveguide as described above is used to transmit a predetermined image signal. The present invention is applied to an image transmission device for transmission.

  The image transmission apparatus according to the second embodiment is not limited to the endoscope system as shown in the first embodiment, but has a high definition represented by a 4K / 8K image exceeding a so-called FHD (Full High Definition). / A transmission device capable of transmitting a large-capacity image signal, in other words, a transmission device having a transmission line of a high-speed signal whose fundamental frequency exceeds 10 GHz.

  Further, it is assumed that the transmission line according to the second embodiment is used in a millimeter wave (including a submillimeter wave) region capable of realizing a communication speed of 5 Gbps or more with a length of about several centimeters to 5 meters or less. And requires flexibility.

  The flexible waveguide including the dielectric material described as the first embodiment can be appropriately applied to an image transmission device such as the second embodiment requiring such conditions. .

  The present invention is not limited to the embodiments described above, and various changes, modifications, and the like can be made without departing from the spirit of the present invention.

1: Endoscope system 2: Endoscope 3: Video processor 6: Insertion section 7: Operation section 8: Universal cord 10: Tip rigid section 20: Imaging unit 21: Imaging optical system 22: Imaging element 23: Driver IC
26: transmitting / receiving circuit 27: transmitting / receiving antenna 33: transmitting / receiving circuit 34: transmitting / receiving antenna 40: flexible substrate 41: control signal line 42: power supply line 43: GND line 44: connector terminal 50: flexible waveguide (waveguide) )
51: Internal dielectric (first dielectric)
52: Internal dielectric (second dielectric)
53: Outer conductor 54: String hole

Claims (5)

A linear dielectric whose dielectric constant is uniform in the longitudinal direction, and whose cross section has the same shape in the longitudinal direction;
An outer conductor disposed at a position covering the outer periphery of the dielectric, and formed of a flexible tubular member,
Having a flexible waveguide that conducts radio waves in a frequency band of millimeter waves or sub-millimeter waves or more near 60 GHz or more,
A flexible waveguide, comprising: a flexible substrate disposed so as to be wound around an outer surface of the outer conductor. 2. The flexible waveguide according to claim 1, wherein the flexible substrate has a line for transmitting a predetermined AC signal or DC voltage therein. 3. An image transmission device having the flexible waveguide according to claim 1,
An image transmission device having a flexible waveguide, wherein the flexible waveguide transmits a predetermined image signal. An endoscope having the flexible waveguide according to claim 1,
An endoscope having a flexible waveguide, wherein the flexible waveguide transmits a predetermined image signal. An endoscope according to claim 4,
An image processing unit that performs predetermined image processing on a predetermined image signal transmitted by the flexible waveguide;
An endoscope system comprising:

Images