JP2020058524A - Flexible waveguide, image transmission device having flexible waveguide, endoscope and endoscope system having flexible waveguide - Google Patents

Abstract

To achieve both of the proper flexibility and excellent transmission characteristic in a flexible waveguide of transmitting an electric wave at the frequency equal to or greater than the desired millimeter wave (including the sub-millimeter wave).SOLUTION: A flexible waveguide 50 includes: a linear dielectric body 51 which has the uniform dielectric constant in the longitudinal direction and in which the cross sections perpendicular to the longitudinal direction have the same shape; and a flexible external conductor 53 which is arranged on the outer periphery of the linear dielectric body 51 and has a metal layer on the inner surface. The cross section of the dielectric body 51 forms the ridge shape. The external conductor 53 has the braid structure.SELECTED DRAWING: Figure 8

Description

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

  In recent years, a communication environment having a communication speed exceeding 1 Gbps has permeated even ordinary homes by a technique 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 the speed of information processing, that is, “hard performance” have been significantly improved.

  In addition, the quality of information that can be used by individuals or companies by using high-definition / large-capacity video represented by 4K / 8K images that exceed the so-called FHD (Full High Definition) and expanding information access via the Internet. The amount and quantity, that is, "software usage" has also expanded dramatically.

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

  In this way, the improvement of "hardware performance" and the expansion of "use of software" have become the two wheels, and the technology in recent years has remarkably developed and new added value has been born. As a result, the performance required for information communication technology at present is higher than ever before. When attention is paid to the signal transmission line among the technical elements necessary for information communication, it can be seen that the performance required in this field is remarkably high.

  Here, at present, "electrical interconnection (connection by metal wire) is mainly used in a region where the transmission distance is short and the transmission speed is low", while "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 by optical fiber) is mainly used.

  That is, for example, the electrical interconnection in a few meters has a usable transmission speed of about 2.5 Gbps, and if it exceeds this, optical interconnection (optical communication) becomes a promising means.

  As described above, optical communication is considered to be an effective means in a region where the transmission distance is long and the transmission speed is high, but it is known that the optical communication has a problem related to the reliability of signal transmission. That is, since an optical fiber for communication is generally composed of a single wire containing silica glass as a main component, there is a risk that the optical fiber, which is a signal transmission path, may be unexpectedly cut due to an unintended impact or the like. is there.

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

  By the way, in the electric interconnection (connection by a metal wire), a line is generally composed of a plurality of thin wires bundled, and even when the wires are cut, the thin wires are gradually cut, so that the communication performance gradually deteriorates, By knowing the deterioration of communication performance, it is possible to take measures such as repairs in advance. Further, 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 in that the influence of dust can be easily eliminated.

  That is, due to the existence of the above problems, it is considered that optical communication is not a substitute for electrical interconnection particularly in applications where high reliability is required in communication or in applications where line-to-line connections are required.

  In view of the above-mentioned circumstances, the present applicant has proposed a method of realizing 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 a problem of a signal transmission method using a lead wire. International Publication WO 2017/002585 (Patent Document 1) proposes a technique of utilizing a radio wave and a waveguide as a new signal transmission method that overcomes the limitations of the signal transmission method using an optical fiber while overcoming the limitations.

  That is, according to the flexible waveguide disclosed in Patent Document 1, while overcoming the above-described problems (reliability problem, connection-related problem), it is difficult to realize with electrical interconnection on the order of tens of Gbps. A communication line capable of high-speed communication can be realized.

  Further, Patent Document 1 describes a video endoscope system using the above-mentioned communication line, and discusses that there is a high need for the above-described high-speed communication in the video endoscope system.

  Incidentally, the endoscope has an elongated insertion portion having sufficient flexibility, and the insertion portion is required to be "as thin as possible". This is because the thickness / thinness of the insertion portion is greatly related to the insertability of the endoscope and, as a result, has a great influence on the utility value of the endoscope. Also, since the endoscope is a medical device, high reliability is an essential requirement. Furthermore, the need for maintenance requires high connectivity.

  As described above, in the video endoscope system, there is a demand for a high-speed transmission line that is compatible with both "thinness" and "flexibility" and has high reliability and connectivity. It can be seen that the waveguide is one of the powerful means as a transmission line.

  The term "flexibility" as used herein means that repeated bending is possible, and simply "bending" is not sufficient.

  By the way, it is generally difficult to realize sufficient flexibility in a waveguide that transmits a radio wave having a frequency higher than a millimeter wave (including a submillimeter wave). However, 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 2), the flexibility of the waveguide is increased by using an insulating thread for the internal dielectric, and the type of the internal dielectric thread is used. Is intended to stabilize the transmission characteristics by generating a distribution in the permittivity.

  Further, in JP-A-2015-185858 (Patent Document 3), a required number of flat foil yarns having a flat cross-sectional shape are assembled around a dielectric in a so-called braided form to form a conductive layer, which is transmitted. Techniques for forming flexible waveguides with low loss are described.

  Further, Japanese Patent No. 5129046 (Patent Document 4) describes a technique for realizing a wide transmission frequency band by widening the impedance range by making the cross section of the conductive layer of the waveguide a so-called "ridge shape". Has been done. Incidentally, the widening of the band by adopting the ridge shape is highly effective in reducing the diameter of the waveguide as described later.

International publication WO2017 / 002585 Patent No. 4724849 JP, 2005-185858, A Japanese Patent No. 5129046

  However, with the techniques described in the above-mentioned Japanese Patent No. 4724849 (Patent Document 2) and Japanese Patent Application Laid-Open No. 2015-185858 (Patent Document 3), although sufficient flexibility can be obtained, it is fine as it is. Cannot be sized.

  In addition, Japanese Patent No. 5129046 (Patent Document 4) shows a ridge waveguide having flexibility, but the cross-sectional shape described in the above specification is defined in the above specification. The electric field concentration may occur due to the influence of the "depression space", and the transmission characteristics may deteriorate.

  The present invention has been made in view of the above circumstances, and fundamentally solves the above-mentioned conventional problems, and provides a waveguide for transmitting radio waves having a frequency of a desired millimeter wave (including sub-millimeter wave) or more. To provide a flexible waveguide having sufficient flexibility and thinness, an image transmission device having the flexible waveguide, an endoscope having the flexible waveguide, and an endoscope system. With the goal.

  A flexible waveguide according to one aspect of the present invention is a linear dielectric having a uniform dielectric constant in the longitudinal direction and the same cross section perpendicular to the longitudinal direction, and the outer periphery of the linear dielectric. And a flexible outer conductor having a metal layer on the inner surface thereof, wherein the cross section of the dielectric forms a ridge shape, and the outer conductor is It has a braid structure.

  An image transmission device according to an aspect of the present invention is an image transmission device having the flexible waveguide, and the waveguide transmits a predetermined image signal.

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

  An endoscope system according to one aspect 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, the said conventional problem is fundamentally solved and it is suitable flexibility and excellent transmission in the waveguide which transmits the electric wave of frequency more than a desired millimeter wave (a submillimeter wave). It is possible to provide a waveguide having compatibility with characteristics, an image transmission device having the waveguide, an endoscope having the waveguide, and an endoscope system.

FIG. 1 is a perspective view showing a schematic configuration of an endoscope system having a flexible waveguide according to the first embodiment of the present invention. FIG. 2 is a block diagram showing a functional configuration of main parts of the endoscope system according to the first embodiment. FIG. 3 is an enlarged perspective view of an essential part showing the structures of the flexible waveguide and the image pickup unit of the first embodiment. FIG. 4 is an enlarged perspective view of an essential part showing a partial cross-section of the structures of the flexible waveguide and the image pickup unit of the first embodiment. FIG. 5 is an enlarged cross-sectional view of a main part schematically showing a configuration example of an internal dielectric having a ridge shape that can be adopted in a waveguide such as the flexible waveguide of the first embodiment. FIG. 6 is an enlarged cross-sectional view of a main part schematically showing another configuration example of the internal dielectric having a ridge shape that can be adopted in a waveguide such as the flexible waveguide of the first embodiment. FIG. 7 is an enlarged cross-sectional view of a main part schematically showing another configuration example of the internal dielectric having a ridge shape that can be adopted in a waveguide such as the flexible waveguide of the first embodiment. FIG. 8 is an enlarged perspective view of an essential part showing a schematic configuration of an essential part of the flexible waveguide of the first embodiment, in which the pressing members arranged outside the outer conductor are shown separated from each other. It is a thing. FIG. 9 is a main part enlarged perspective view showing a schematic configuration of a main part in the flexible waveguide of the first embodiment. FIG. 10 is a cross-sectional view of essential parts showing the braid-shaped outer conductor and inner dielectric in the flexible waveguide of the first embodiment. FIG. 11 is an external view showing the external appearance of a braided outer conductor in the flexible waveguide of the first embodiment. FIG. 12 is an enlarged sectional view of an essential part showing the configuration of the outer conductor in the flexible waveguide of the first embodiment. FIG. 13 is an enlarged perspective view of an essential part showing the structure of the flexible waveguide of the first embodiment. FIG. 14 is an enlarged sectional view of an essential part showing the structure of the flexible waveguide of the first embodiment. FIG. 15 is an enlarged perspective view of an essential part showing an outer conductor and an inner dielectric in the flexible waveguide of the first embodiment. FIG. 16 is an enlarged sectional view of an essential part showing an outer conductor and an inner dielectric in the flexible waveguide of the first embodiment. FIG. 17 is a diagram for explaining the definition of the internal dielectric when creating the simulation model related to the flexible waveguide of the first embodiment. FIG. 18 is a diagram showing the relationship between the dimensions of the internal dielectric and the propagation region of the waveguide when creating the simulation model of the flexible waveguide of the first embodiment. FIG. 19 is a diagram showing a simulation model in which the outer skin of the internal dielectric is a complete conductor in the simulation model according to the flexible waveguide of the first embodiment. FIG. 20 is a diagram showing the transmission characteristics of the simulation model related to the flexible waveguide of the first embodiment. FIG. 21 is a diagram illustrating a propagation region boundary in the simulation model according to the flexible waveguide of the first embodiment. FIG. 22 is a perspective view showing a simulation model A in the case where the simulation model according to the flexible waveguide of the first embodiment has an internal dielectric having a cross-sectional shape without a ridge. FIG. 23 is an enlarged cross-sectional view of a main part showing a simulation model A in the case where the simulation model according to the flexible waveguide of the first embodiment has an internal dielectric having a cross-sectional shape without a ridge. FIG. 24 is a perspective view showing a simulation model B in the case where the simulation model according to the flexible waveguide of the first embodiment has an internal dielectric having a cross-sectional shape with a ridge. FIG. 25 is a cross-sectional view of an essential part showing a simulation model B in the case where the simulation model according to the flexible waveguide of the first embodiment has an internal dielectric having a cross-sectional shape with a ridge. FIG. 26 is a perspective view showing a simulation model C in the case where the simulation model according to the flexible waveguide of the first embodiment has an internal dielectric having the same cross-sectional shape as the example shown in FIG. FIG. 27 is a main-portion cross-sectional view showing a simulation model C in the case where the simulation model related to the flexible waveguide of the first embodiment has an internal dielectric having the same cross-sectional shape as the example shown in FIG. . FIG. 28 is a diagram showing the transmission characteristics of the simulation model A shown in FIGS. 22 and 23 and the simulation model B shown in FIGS. 24 and 25. 29 is a diagram showing the transmission characteristics of the simulation model B shown in FIGS. 24 and 25 and the simulation model C shown in FIGS. 26 and 27. FIG. 30 is an enlarged perspective view of an essential part showing the structure of the flexible waveguide of the second embodiment of the present invention. FIG. 31 is an enlarged sectional view of an essential part showing the structure of the flexible waveguide of the second embodiment. FIG. 32 is an exploded perspective view of essential parts showing a state when the inner dielectric and the outer conductor are inserted into the hollow portion of the pressing member in the flexible waveguide of the second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, prior to explaining the flexible waveguide of the present embodiment, the technical concept of the ridge-shaped internal dielectric material adopted in the flexible waveguide of the present embodiment will be briefly described.

<Technical concept of ridge-shaped internal dielectric>
Generally, in order to realize a thin flexible waveguide, it is effective to form the internal dielectric in a ridge shape as described in the above-mentioned Japanese Patent No. 5129046 (Patent Document 4). It becomes a means. In order to realize an inner dielectric having such a ridge shape, the present invention has a concave portion having a major axis and a minor axis in a cross section perpendicular to the longitudinal direction and at least one side of a pair of major sides having the major axis being concave inward A dielectric having a shape, so-called “ridge shape” is arranged inside.

  5 to 7 are enlarged cross-sectional views of a main part schematically showing a configuration example of an internal dielectric body having a ridge shape, which can be adopted in a waveguide such as the flexible waveguide of the first embodiment. Is.

  Here, FIG. 5 shows an internal dielectric 51A having a so-called double ridge shape, FIG. 6 shows an internal dielectric 51B having a so-called single ridge shape, and FIG. 7 swells on both sides of the ridge portion. The internal dielectric 51C having a so-called cocoon shape in which a curved surface portion is formed is shown.

  The internal dielectric 51A having a double ridge shape shown in FIG. 5 and the internal dielectric 51B having a single ridge shape shown in FIG. 6 include round corners (so-called “corner R” shapes).

<Schematic configuration of the present invention employing an internal dielectric having a ridge shape>
By the way, in a flexible waveguide including an internal dielectric having a ridge-shaped cross section as described above, in order to realize an external conductor that engages with the internal dielectric, the surface of the internal dielectric having the ridge is formed. And the inner surface of the outer conductor having the metal layer on the inner surface.

  As a means for achieving this, the present inventor has proposed a structure in which a pressing member having the same shape in a cross section perpendicular to the longitudinal direction is arranged outside the outer conductor along the ridge portion of the inner dielectric. , Further clarified its feasible structure.

  FIG. 8 is an enlarged perspective view of an essential part showing a schematic configuration of an essential part of the flexible waveguide of the first embodiment, in which the pressing members arranged outside the outer conductor are shown separated from each other. It is a thing. Further, FIG. 9 is an enlarged perspective view of an essential part showing a schematic configuration of an essential part of the flexible waveguide of the first embodiment.

  As shown in FIGS. 8 and 9, the flexible waveguide 50 of the present embodiment includes an inner dielectric 51, an outer conductor 53, and two pressing members 56a and 56b.

  The internal dielectric 51 is a linear dielectric having a uniform dielectric constant in the longitudinal direction and the same cross section perpendicular to the longitudinal direction, and the cross section perpendicular to the longitudinal direction has a major axis and a minor axis. At least one side of a pair of long sides forming the major axis forms a concave portion that is recessed inward. In the embodiment, a so-called double ridge shape is formed in which ridge-shaped concave portions 51a and 51b are formed as a cross-sectional shape perpendicular to the longitudinal direction.

  Further, the outer peripheral surfaces of both ends of the ridge-shaped recesses 51a and 51b of the inner dielectric 51 are formed with curved surface portions so as to contact with the curved surface of the inner surface of the outer conductor 53 having a substantially cylindrical shape described later.

  The outer conductor 53 is a flexible outer conductor that is disposed on the outer periphery of the linear inner dielectric 51 and has a metal layer 55a (see FIG. 12) on the inner surface. Further, as shown in FIG. 8, in the present embodiment, the outer conductor 53 has a substantially cylindrical shape, and is disposed at least in contact with the outer peripheral surfaces of both ends of the inner dielectric 51.

  The pressing members 56a and 56b are substantially rod-shaped linear members in the present embodiment, and as shown in FIG. 8, outside the outer conductor 53, the ridge-shaped recesses 51a and 51b of the inner dielectric body 51 are respectively formed. It is arranged at a position facing each other. That is, the pressing member 56a is disposed at a position facing the ridge-shaped recess 51a in the inner dielectric 51 with the outer conductor 53 sandwiched therebetween, and the outer conductor is positioned at a position facing the ridge-shaped recess 51b in the inner dielectric 51. A pressing member 56b is arranged so as to sandwich 53.

  In the present embodiment, the pressing member 56a and the pressing member 56b, which are respectively arranged outside the outer conductor 53, are sandwiched between the ridge-shaped recess 51a and the ridge-shaped recess 51b via the outer conductor 53, respectively. The outer conductor 53 is pressed so as to abut.

  FIG. 9 shows a state after the pressing members 56a and 56b are pressed against the outer conductor 53. As shown in FIG. 9, the outer conductor 53 is pressed by the pressing members 56 a and 56 b to be deformed and brought into close contact with the inner dielectric body 51.

  Specifically, the outer conductor 53 pressed by the pressing member 56a is deformed at the portion in contact with the ridge-shaped recess 51a to form the outer conductor recessed surface 53a, and is brought into close contact with the ridge-shaped recess 51a. Similarly, the outer conductor 53 pressed by the pressing member 56b is deformed at a portion in contact with the ridge-shaped recess 51b to form an outer conductor recessed surface 53b, and is brought into close contact with the ridge-shaped recess 51b.

  As a result, the pressing members 56a and 56b are arranged so as to extend in the longitudinal direction along the ridge-shaped recesses 51a and 51b in the internal dielectric 51.

  In addition, in the present embodiment, the pressing members 56a and 56b are used to deform the outer conductor 53 to hold the surface of the inner dielectric 51 and the inner surface of the outer conductor 53 in close contact with each other.

  In order to realize a structure in which the outer conductor 53 is deformed and the surface of the inner dielectric 51 and the inner surface of the outer conductor 53 are held in close contact with each other, the outer conductor 53 needs to have flexibility.

  As a method of giving flexibility to the outer conductor, for example, a thread containing a metal layer (flat foil thread) is assembled into a braided shape to form the outer conductor (braided structure), and a metal tape is wound to form the outer conductor. The outer conductor may be formed (bandaged structure) or formed by forming irregularities in a direction perpendicular to the propagation direction of the waveguide (bellows structure). Most preferred is the formation of an outer conductor by structure.

<Example of configuration of outer conductor>
Next, a configuration example of the outer conductor 53 in the present embodiment that employs the braid structure described above will be briefly described.

  FIG. 10 is a cross-sectional view of a main part showing an outer conductor and an inner dielectric body having a braided shape in the flexible waveguide of the first embodiment, and FIG. 11 is a flexible view of the first embodiment. It is an external view showing the external appearance of the braided outer conductor in the waveguide. Further, FIG. 12 is an enlarged cross-sectional view of a main part showing a configuration of an outer conductor in the flexible waveguide of the first embodiment.

  In the present embodiment, the outer conductor 53 is arranged at a position that covers the outer periphery of the inner dielectric body, and is configured to have a flexible tubular metal layer portion. Specifically, the outer conductor 53 is composed of a plurality of strip-shaped flat foil yarns.

  As shown in FIG. 12, the strip-shaped flat foil yarn has a rectangular cross section perpendicular to the stretching direction, and includes a base layer 55b containing a non-metal substance such as resin and a metal foil 55a containing a metal substance. Configured to have. More specifically, in the flat foil yarn, a resin film (for example, polyethylene terephthalate (PET)) having a thickness of 25 μm is used as the underlayer 55b, and a copper foil having a thickness of 9 μm is used as the metal foil 55a. It is formed in a band shape with a width of 0.3 mm.

  Further, the outer conductor 53 is formed by assembling a plurality of (for example, 32) flat foil threads into a cylindrical braid shape as shown in FIG. Specifically, the metal foil 55a is arranged so as to be wound around the outer peripheral surface of the inner dielectric 51 so as to be wound, and the flat foil threads are knitted so as to form a braided form. It has become.

The outer conductor 53 includes the predetermined metal layer portion (metal foil 55a) as described above, and the conductivity of the metal foil 55a is set to 59 × 10 ⁶ S / m, which is equivalent to pure copper. Although the conductivity is uniquely determined here, the conductivity of the metal layer portion is not limited to this in the present invention, 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 thread which is the outer conductor 53 is configured such that the metal foil 55a is arranged on the side in contact with the dielectric 51 and the resin film is provided on the outer side, but the invention is not limited to this. Instead, it may be composed of only a metal layer.

  FIG. 11 is an external view showing an external appearance of an outer conductor formed by braiding flat foil yarns in a braided shape in the flexible waveguide of the first embodiment. As described above, when a plurality of flat foil yarns, which are the outer conductors 53, are wound around the outer periphery of the inner dielectric body 51 at an angle of, for example, 45 degrees and assembled into a braid, a so-called "manufacturing A hole called a "string hole" occurs. In addition, in FIG. 11, this cord making hole is indicated by reference numeral 54.

  The surface of the internal dielectric 51 on the lower side is exposed in the "hole" portion of the cord forming hole 54. As described above, in the flexible waveguide 50 of the present embodiment, the outer conductor 53 is formed so 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 this embodiment, the shape of the outer conductor 53 is periodically changed in the longitudinal direction, and the resistance (impedance) distribution of the outer conductor is predetermined with respect to the propagation direction. It will change with the periodicity of.

  As described above, in the flexible waveguide 50 of the present embodiment, not only the ridge structure that is advantageous for reducing the diameter is obtained as described above, but also the flexible waveguide 50 is described in Japanese Patent No. 5129046 (Patent Document 4). Such a depressed space does not occur, and there is no fear that the transmission characteristics will deteriorate. That is, according to the present embodiment, it is possible to realize a waveguide having excellent flexibility while achieving both a reduced diameter and a transmission characteristic.

<Details of First Embodiment>
Hereinafter, the flexible waveguide of the first embodiment will be described in more detail.

  Note that each of the embodiments described below will be described by taking an endoscope system having the flexible waveguide of each embodiment as an example.

  Further, the present invention is not limited to the embodiments. Furthermore, it should be noted that the drawings are schematic, and the relationship between the thickness and width of each member, the ratio of each member, and the like are different from reality. Also, the drawings include portions having different dimensions and ratios.

  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. It is a block diagram showing a functional configuration of a main part of the system.

  As shown in FIG. 1, the endoscope system 1 is a so-called upper digestive tract endoscope system, in which the in-vivo image of the subject P is captured by inserting the tip into the body cavity of the subject P. The endoscope 2 includes an image pickup unit that outputs an image signal of a subject image, and an endoscope that includes an image processing unit that performs predetermined image processing on the image signal output from the image pickup unit of the endoscope 2. A video processor 3 that totally controls the operation of the entire system 1, a light source device 4 that generates illumination light to be emitted from the distal end of the endoscope 2, and an image that has been subjected to image processing by the video processor 3 are displayed. And a display device 5 that operates.

  The endoscope 2 is provided with the above-mentioned image pickup section at the distal end and is provided with an insertion section 6 mainly composed of an elongated shape section having flexibility, and is connected to the proximal end side of the insertion section 6 to input various operation signals. An operation unit 7 that receives the operation unit 7 and a universal cord 8 that extends from the operation unit 7 toward the base end side and is connected to the video processor 3 and the light source device 4 are provided.

  Here, in the endoscope 2, between the image pickup unit provided at the distal end of the insertion unit 6 and the image processing unit of the video processor 3, the image pickup unit of the insertion unit 6 to the insertion unit 6 and the operation unit 7 are inserted. And a signal transmission path that extends to the image processing unit of the video processor 3 through the inside of each of the universal cords 8 and that transmits an image signal or 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, typically referred to as a millimeter wave). (The “waveguide” will be described later in detail).

  The insertion portion 6 is arranged at the most distal end portion, and has a distal end rigid portion 10 having an image pickup element 22 and the like forming the imaging portion therein, and a proximal end side of the distal end rigid portion 10, and a plurality of curved portions. A bendable bending portion 9 configured by a piece, and a flexible elongated tube portion connected to the proximal end side of the bending portion 9 are provided.

  In addition, as shown in FIG. 2, in the present embodiment, the distal end rigid portion 10 disposed at the most distal end of the insertion portion 6 has an imaging optical system 21 for receiving a subject image and a rear portion of the imaging optical system 21. And an image pickup unit 20 including an image pickup element 22 for picking up a subject image and outputting 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, receives the light condensed by the image pickup optical system 21, and photoelectrically converts the light into an electric signal. The driver IC 23 is provided on the end side and drives the image pickup element 22 and performs predetermined processing on the image pickup signal output from the image pickup element 22, and the driver IC 23 is provided on the base end side of the driver IC 23 and has a waveguide (flexibility). A transmission / reception antenna 27 (which will be described later in detail) for transmitting and receiving a signal via a waveguide) 150 (which will be described later in detail).

  In the present embodiment, the image pickup device 22 is a CMOS (Complementary Metal Oxide Semiconductor) image sensor and has an image sensor having a pixel number of 2 million pixels or more, which is a pixel number corresponding to a so-called full high definition or higher. To do.

  The driver IC 23 outputs an analog front end (AFE) 24 that performs noise removal and A / D conversion to the electric signal output from the image pickup device 22, a drive timing of the image pickup device 22, and various signal processing pulses in the AFE 24 and the like. In order to connect the generated timing generator (TG) 25 and the transmission / reception antenna 27, and to transmit / receive the digital signal output from the AFE 24 via the flexible waveguide 150 to / from the image processing unit in the video processor 3. And a control section (not shown) that controls the operation of the image sensor 22.

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

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

  The image pickup device 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 etc.).

  On the other hand, the video processor 3 includes an image signal processing circuit 31 as the image processing unit that performs a predetermined image processing on the image signal output from the imaging unit 20 in the endoscope 2, and the imaging in the endoscope 2. A power supply circuit 32 that generates power for supplying power to the element 22 and the like, and a transmission / reception for transmitting / receiving a predetermined signal to / from the imaging unit 20 in the endoscope 2 via the flexible waveguide 150. The circuit 33 and the transmission / reception antenna 34 connected to the transmission / reception circuit 33 are provided.

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

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

  Further, as shown in FIG. 2, the flexible waveguide 150 as a signal transmission path is internally provided in the insertion portion 6, the operation portion 7 and the universal cord 8 of the endoscope 2 as described above. However, various signal lines are arranged inside the universal cord 8 and the like in parallel with the flexible waveguide 150.

  That is, in the universal cord 8, as shown in FIG. 2, a control signal line 41 for transmitting various control signals supplied from the image signal processing circuit 31 in the video processor 3 and a power supply supplied from the power supply circuit 32 are provided. A power supply line 42 and a ground line (GND line) 43 for transmission are arranged respectively.

  Then, a predetermined control signal (for example, a clock signal, a synchronization signal, etc.) is supplied to each circuit of the image pickup device 22 and the driver IC 23 of the endoscope 2 through the control signal line 41. There is.

  Similarly, power is supplied from the power supply circuit 32 of the video processor 3 to the image pickup device 22 of the endoscope 2 and the circuits of the driver IC 23 via the power supply line 42 and the ground line (GND line) 43. It is supposed to be done.

<Flexible Waveguide, Transceiver Circuit, and Imaging Unit>
Next, a waveguide (flexible waveguide) and a transmission / reception circuit in the endoscope system according to the present embodiment, and peripheral circuits (imaging unit etc.) thereof will be described.

  INDUSTRIAL APPLICABILITY The present invention provides a flexible waveguide used in a millimeter wave region (including a submillimeter wave) including a dielectric mixed material that appropriately satisfies the three conditions of high permittivity, low dielectric loss tangent, and 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 replaces the signal transmission system using a lead wire and the signal transmission system using an optical fiber, which have been conventionally used as a signal transmission system that connects an image pickup unit in the endoscope and an image processing unit in a video processor, with a millimeter wave. Alternatively, a signal transmission method using a waveguide (flexible waveguide) that allows submillimeter waves (radio waves having a frequency of approximately 30 to 600 GHz) to pass therethrough is newly proposed.

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

  As shown in FIG. 2, the image pickup unit 20 is provided behind the image pickup optical system 21 which receives the image of the subject in the distal end rigid portion 10 provided at the most distal end of the insertion section 6. In addition, as described above, the image pickup unit 20 includes the image pickup device 22 that picks up the subject image and outputs a predetermined image signal by photoelectric conversion, and from the image pickup unit 20 toward the insertion section base end side. The waveguide (flexible waveguide) 150 is extended.

  Further, as described above, the image pickup unit 20 is arranged on the image pickup element 22 that receives the light condensed by the image pickup optical system 21 and photoelectrically converts it into an electric signal, and on the proximal end side near the image pickup element 22. A driver IC 23 that drives the image pickup device 22 and performs a predetermined process on the image pickup signal output from the image pickup device 22, and a driver IC 23 that is provided at the base end side of the driver IC 23 and that transmits and receives signals via the flexible waveguide 150. And a transmitting / receiving antenna 27 for

  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, but is connected to the image sensor 22 via the ceramic substrate 28. It has become so.

<Structure of flexible waveguide>
FIG. 3 is an enlarged perspective view of an essential part showing the structures of the flexible waveguide and the imaging unit of the first embodiment, and FIG. 4 is the flexible waveguide of the first embodiment. FIG. 3 is an enlarged perspective view of a main part showing the structure of the imaging unit in a partial cross section. In addition, FIG. 13 is an enlarged perspective view showing the configuration of the outer conductor and the inner dielectric according to the flexible waveguide of the first embodiment, and FIG. 14 shows a cross section in a direction perpendicular to the longitudinal direction. It is an expanded sectional view.

  Although the outer conductor 153 of the flexible waveguide 150 is shown to have a predetermined thickness in FIGS. 3, 4, 13, and 14, the drawings are schematic ones. The shape of the conductor 153, the relationship between the thickness and width of each member, the ratio of each member, and the like are different from reality.

  As shown in FIGS. 3 and 4, on the proximal side of the driver IC 23, the flexible conductor for transmitting a millimeter wave or a submillimeter wave is sandwiched by sandwiching the transmission / reception antenna 27 integrated in the package of the driver IC 23. The tip of the wave tube 150 is connected.

  The flexible waveguide 150 (hereinafter, also referred to as “waveguide 150”) has flexibility, and after the distal end side is connected to the driver IC 23 arranged in the distal end rigid portion 10, the insertion portion is inserted. 6 is extended toward the base end side.

  More specifically, the flexible waveguide 150 is further proximal to the driver IC 23 in the insertion portion 6, that is, the proximal end portion from the disposition portion of the driver IC 23 in the distal end rigid portion 10 to the proximal end portion. After being inserted 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 so as to be arranged at a position reaching the video processor 3. It has become.

  The proximal end side of the flexible waveguide 150 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 150 is a signal transmission line that connects the image pickup unit 20 and the image processing unit (image processing circuit 31) in the video processor 3, and at least a part of the signal propagates a millimeter wave or a submillimeter wave. It is a waveguide.

  As shown in FIGS. 13 and 14, the flexible waveguide 150 has an inner dielectric 151 having a uniform dielectric constant in the longitudinal direction and the same cross section in the longitudinal direction and a ridge shape in the cross section. , An outer conductor 153 disposed at a position covering the outer periphery of the inner dielectric 151. The outer conductor 153 has flexibility, and pressing members 156a and 156b are arranged on the outer conductor concave surfaces 153a and 153b of the outer conductor 153 in parallel with the ridge-shaped portions 151a and 151b (recesses) of the inner dielectric 151. Is provided, and the inner surface of the outer conductor 153 and the inner dielectric surface are in close contact with each other by the pressing members 156a and 156b.

  In addition, the pressing members 156a and 156b press the inner surface of the outer conductor 153 in parallel with the ridge-shaped portions 151a and 151b (recesses) of the inner dielectric 151 and toward the center of the inner dielectric 151 to deform and close them. In order to maintain the maintained state, a cylindrical member 155 having elasticity is arranged from the outside of the pressing members 156a and 156b.

<Inner dielectric and outer conductor in flexible waveguide>
FIG. 15 is an enlarged perspective view of an essential part showing the configuration of the outer conductor and the inner dielectric according to the flexible waveguide of the first embodiment, and FIG. 16 shows a cross section in a direction perpendicular to the longitudinal direction. It is a principal part expanded sectional view.

  In the present embodiment, the flexible waveguide 150 covers a linear inner dielectric 151 having a uniform dielectric constant in the longitudinal direction and the same cross section in the longitudinal direction, and the outer periphery of the internal dielectric 153. The outer conductor 153 is provided at a position and includes a metal layer formed of a flexible cylinder.

The internal dielectric 151 has a cross-sectional shape in which the ratio of the major axis to the minor axis is constant in the longitudinal direction, and includes ridge-shaped portions 151a and 151b (recesses) on at least one side in the major axis direction. Specifically, as shown in FIG. 16, a shape having a long side and a short side is formed, and a concave portion having a predetermined width and depth is formed around the midpoint of the long side.
Long side a = 2.53 mm, short side = 1.265 mm,
Maximum width of the recess s = 0.9325 mm, depth of the recess d = 0.3 mm
Is set to Further, in this embodiment, the relative dielectric constant εr of the internal dielectric is set to 1.3.

  Incidentally, in the present embodiment, “uniform in permittivity” means that the permittivity is uniform when viewed in a wavelength order dimension of a radio wave (millimeter wave or submillimeter wave) propagating inside the waveguide. . That is, since the dielectric constant distribution due to the structure whose size is different from the wavelength order by 1 to 2 digits or more does not affect the radio waves propagating inside the waveguide, in the present embodiment, the dielectric constant including this is not included. Expressed as uniform.

  In this embodiment, it is assumed that the internal dielectric 151 is made of a flexible dielectric material such as expanded PTFE (polytetrafluoroethylene) or expanded polyethylene. Alternatively, a dielectric mixture material obtained by mixing a base material resin material (for example, nonpolar resin such as PTFE or polyethylene) and a crystal material (for example, powdered crystal material with low dielectric loss such as α-alumina) is used. You may.

  On the other hand, the outer conductor 153 includes a predetermined metal layer portion arranged so as to cover the outer peripheral portion of the inner dielectric 151. Here, as the metal, a metal having a high conductivity such as gold, silver, copper, or aluminum is set. In the present invention, it is preferable to use a metal layer having good conductivity for the metal layer portion.

<Study on the effect of reducing the diameter of a waveguide with a ridge-shaped cross section>
Here, the effect of reducing the diameter of the waveguide having a ridge-shaped cross section will be described with respect to the present invention.

  The cross-sectional shape of the internal dielectric is defined as shown in FIG. Let a be the long-side dimension (long side) of the waveguide, and the short-side dimension be half the long-side dimension, that is, a / 2. Further, a concave portion is provided centering on the midpoint of the long side, and the concave portion has a width (ridge width) of s and a depth (ridge depth) of d.

  At this time, paying attention to the waveguide long side a and the ridge width s at a certain ridge depth d, the waveguide long side a and the ridge width s are changed so that the cutoff frequencies have the same values (for example, 60 GHz). At this time, the relationship between the dimensions of the internal dielectric and the propagation region of the waveguide becomes a curve graph as shown in FIG. This curve shows the propagation region boundary of the waveguide, that is, the cutoff frequency (cutoff wavelength), and shows that the radio wave can propagate in the waveguide within the range of the hatched portion.

  Based on this concept, a simulation model (SM1; FIG. 19) in which the inner dielectric has a perfect conductor with a relative permittivity εr of 1.3 and a cutoff frequency of 60 GHz was prepared, and an electromagnetic field simulator was created. The transmission simulation used was carried out. Here, the meanings of the symbols are as shown in FIG. The result of the simulation is shown in FIG.

  This result represents the boundary of the propagation region when the long side a, the ridge width s, and the ridge depth d of the waveguide obtained from the simulation result are changed. Further, a point (A) in FIG. 20 represents a ridge width s = 0 and a ridge depth d = 0, that is, a waveguide without a ridge. From this result, it is understood that the larger the ridge width s and the ridge depth d, the smaller the length a of the long side of the waveguide, that is, the “thinner” of the waveguide.

  Note that FIG. 20 shows the results when the relative permittivity εr of the internal dielectric is εr = 1.3 and the cutoff frequency is 60 GHz. This result is obtained by changing the relative permittivity and the cutoff frequency of the internal dielectric. Change.

  FIG. 21 shows the long side a of the waveguide and the ridge width s when the cutoff frequency is 40 GHz (V band: 50 to 75 GHz can be propagated) and the relative dielectric constant of the internal dielectric is 1.3. , The propagation region boundary is calculated when the ridge depth d is changed.

  In order to verify this result, the simulation model shown in FIGS. 22, 23, 24, and 25 (FIG. 22, FIG. 23: model A (SM -A), FIG. 24, and FIG. 25: Model B (SM-B)) was prepared and a transmission simulation was performed. As the common specifications of the model A (SM-A) and the model B (SM-B), the relative permittivity εr = 1.3 and the dielectric loss tangent tanδ = of the internal dielectrics 151A (SM-A) and 151B (SM-B). 0, the material of the outer conductors 153A (SM-A), 153B (SM-B) is equivalent to pure copper (electrical conductivity: 59 × 10 ^ 6 [S / m]), and the thickness of the outer conductors 153A, 153B is set to 0. The length was 1 mm and the waveguide length was 20 mm.

  Here, FIG. 22 and FIG. 23 show a simulation model A (SM-A) having a ridgeless cross-sectional shape based on the common specifications. 24 and 25 show a simulation model B (SM-B) having a ridge and having a cross-sectional shape based on the common specifications, in which the ridge width s = 0.9 mm and the ridge depth d = 0.3 mm, The ridge width and ridge depth are the same as the cross-sectional shape shown in FIG.

  FIG. 28 is a transmission simulation result (transmission characteristic for each frequency) in the waveguide model of FIGS. 22 to 25. The horizontal axis represents frequency (in GHz) and the vertical axis represents transmission characteristics in decibel (dB) units. The closer the numerical value to the vertical axis is, the better the transmission characteristics.

  In FIG. 28, the solid line shows the transmission characteristics of the model A (SM-A) and the dotted line shows the transmission characteristics of the model B (SM-B). Both the model A (SM-A) and the model B (SM-B) have cutoff frequencies around 40 GHz, and it can be seen that stable transmission characteristics can be obtained at a millimeter wave frequency of 60 GHz. Further, comparing the outermost diameter of the internal dielectric, that is, the long side a, the model A (SM-A) without the ridge shape is 3.3 mm, while the model B (SM-B) with the ridge shape is , 2.53 mm, which means that the cross-sectional dimension of the waveguide is small, that is, "the diameter of the waveguide can be reduced".

<Specific Configuration of Flexible Waveguide of First Embodiment>
A specific structure of the flexible waveguide based on the above verification will be described.

  The shape of the flexible waveguide 150 shown in the present embodiment is the same as that of FIG. 15 described above, and the shape shown in FIGS. 24 and 25 has the same major axis, ridge width, and ridge depth as those of FIG. The difference is that the ridge portion in the side direction has a semicircular shape, and the short side direction is a curve. With the shape of FIG. 15, the adhesion between the surface of the inner dielectric 151 and the outer conductor 153 can be further enhanced, and the cross-sectional shape of the conductor layer can be stabilized.

  A simulation model C (SM-C) was also produced for the shape shown in FIG. 15 (see FIGS. 26 and 27), and a transmission simulation was performed. Here, the relative permittivity and dielectric loss tangent of the internal dielectric, the material and thickness of the external conductor, and the waveguide length were set to the same conditions as those of the simulation model shown in FIGS. 24 and 25 (this is model C (SM-C ) Will be called).

  FIG. 29 is a transmission simulation result (transmission characteristic for each frequency) in the waveguide model of FIGS. 24, 25, and 15 (see FIGS. 26 and 27). The horizontal axis represents frequency (in GHz) and the vertical axis represents transmission characteristics in decibel (dB) units. The closer the numerical value to the vertical axis is, the better the transmission characteristics. In FIG. 29, the solid line shows the transmission characteristics of the model B (SM-B) and the dotted line shows the transmission characteristics of the model C (SM-C).

  Compared with the model B (SM-B), the model C (SM-C) has a cutoff frequency shifted to the high frequency side, but at a millimeter wave frequency of 60 GHz, it is almost the same as the model B (SM-B). It can be seen that the transmission characteristics of are obtained. Thereby, even in the shape of FIG. 15 (see FIGS. 26 and 27), a flexible waveguide having a small diameter and stable transmission characteristics can be realized.

<Modification>
The pressing members 156a and 156b may have a shape along the ridge shapes 151a and 151b of the internal dielectric 151, and the material is preferably a flexible shape such as silicone rubber or foamed PTFE. Further, other functions may be added to the pressing members 156a and 156b, for example, an optical fiber may be arranged as a pressing member to function as a light guide, or an electric wire may be used to supply a power line, or You may make it function as a control line. Furthermore, a tube having a hollow shape may be used. For example, when the endoscope system is provided with the flexible waveguide 150 of this shape, a path for inserting a treatment tool such as a biopsy forceps or a high-frequency snare can be secured from the hollow hole. it can.

  Further, the elastic cylindrical member 155 may have flexibility, and for example, a string made of thread (braided structure), bandage winding using a tape, and a rubber tube having heat shrinkability are arranged. It can be realized by doing. In addition, the tubular member 155 may be added with another function. For example, by using the rubber tube, the waveguide can have a waterproof function.

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

  Since the configuration of the endoscope system according to the second embodiment is basically the same as that of the first embodiment, only the differences from the first embodiment will be described here, and the other parts will not be described. Detailed description is omitted.

  That is, the endoscope system according to the second embodiment is similar to the first embodiment with respect to the flexible waveguide, but is provided outside the outer conductor of the flexible waveguide. The configuration of the pressing member to be arranged is different, and the configuration is basically the same as that of the first embodiment.

  Specifically, in the pressing members 156a and 156b in the first embodiment, one pressing member is arranged on each long side of the ridge shapes 151a and 151b (recesses) of the internal dielectric 151. Thus, the second embodiment has a shape in which the plurality of pressing members are integrated. Further, it is additionally stated that the characteristics, such as the material, the shape, and the transmission loss, of the flexible waveguide shown in this embodiment are the same as those of the flexible waveguide described in the first embodiment. .

  FIG. 30 is a perspective view showing a flexible waveguide of the second embodiment of the present invention, and FIG. 31 is a sectional view.

  Similar to the first embodiment, the flexible waveguide 250 includes an internal dielectric body 251 having a uniform dielectric constant in the longitudinal direction and a ridge-shaped cross section having the same cross section in the longitudinal direction, and an internal dielectric body 251. The external conductor 253 having flexibility is provided at a position covering the outer periphery of 251. The inner surface of the outer conductor 253 and the surface of the inner dielectric body 253 are formed by a pressing member 256 having a hollow structure provided outside the outer conductor 253 and having a convex shape facing the ridge-shaped portion (recess) of the inner dielectric body 251. And are in close contact.

  More specifically, as shown in FIG. 32, the flexible waveguide 250 in which the inner dielectric 251 has a ridge shape is formed into a convex shape that faces the ridge-shaped portion (recess) of the inner dielectric 251. By inserting into the hollow portion (hole) 257 of the pressing member 256 having the hollow structure, the outer conductor 253 is deformed, and the inner surface of the outer conductor 253 and the surface of the inner dielectric body 251 are in close contact with each other. The structure shown in FIG. 30 is obtained.

  According to this embodiment, it is not necessary to dispose a tubular member for fixing the pressing member 256, and it is possible to realize a flexible waveguide having a simple structure and a small diameter and stable transmission characteristics.

  The pressing member 256 may have a shape that follows the ridge shape of the internal dielectric 251, and the material is preferably a flexible shape such as silicone rubber or expanded PTFE.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.

  In the first and second embodiments described above, the flexible waveguide as described above is applied to the endoscope, but in the third embodiment, the flexible waveguide as described above is provided in a predetermined manner. The present invention is applied to an image transmission device that transmits an image signal.

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

  Furthermore, it is assumed that the transmission line according to the third embodiment is used in a millimeter wave (including submillimeter wave) region in which a communication speed of 5 Gbps or more can be realized with a length of several centimeters to 5 meters or less. There is something that requires flexibility.

  The flexible waveguide including the dielectric material described as the first embodiment can be appropriately applied even to the image transmission device according to the third embodiment which requires such conditions. .

  The present invention is not limited to the embodiments described above, and various changes and modifications 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 code 10: Tip rigid section 20: Imaging unit 21: Imaging optical system 22: Imaging element 23: Driver IC
26: Transmission / reception circuit 27: Transmission / reception antenna 33: Transmission / reception circuit 34: Transmission / reception antenna 41: Control signal line 42: Power supply line 43: GND line 50, 150, 250: Flexible waveguide (waveguide)
51, 151, 251: Internal dielectrics 51a, 51b: Ridge-shaped concave portions 151a, 151b: Ridge-shaped concave portions 53, 153, 253: External conductors 53a, 53b: External conductor concave surfaces 153a, 153b: External conductor concave surface 54: String forming hole 155: Cylindrical members 56a, 56b: Pressing members 156a, 156b: Pressing member 256: Pressing member

Claims (13)

A linear dielectric having a uniform dielectric constant in the longitudinal direction and having the same cross section perpendicular to the longitudinal direction,
A flexible outer conductor disposed on the outer periphery of the linear dielectric and having a metal layer on the inner surface;
A flexible waveguide having
The flexible waveguide, wherein the cross section of the dielectric forms a ridge shape, and the outer conductor has a braid structure. A linear dielectric having a uniform dielectric constant in the longitudinal direction and having the same cross section perpendicular to the longitudinal direction,
A flexible outer conductor disposed on the outer periphery of the linear dielectric and having a metal layer on the inner surface;
A pressing member which is arranged outside the outer conductor and has the same cross-section perpendicular to the longitudinal direction;
A flexible waveguide having
The linear dielectric has a cross section perpendicular to the longitudinal direction having a major axis and a minor axis, and at least one side of a pair of major sides forming the major axis forms a concave portion that is recessed inward,
The flexible waveguide is arranged so that the pressing member extends in the longitudinal direction along the concave portion of the dielectric. The outer conductor has a plurality of strips containing a metal substance, the cross section of which is perpendicular to the extending direction has a rectangular cross section,
In any of the plurality of strip-shaped portions, the flat portion of the strip-shaped portion is the dielectric when the side edge portion of the strip-shaped portion forms a predetermined angle with the longitudinal direction of the flexible waveguide. The flexible waveguide according to claim 1 or 2, wherein the flexible waveguide is extended so as to be wound around the outer peripheral surface of the body and is knitted so that the band-shaped portions thereof form a braided shape. . The flexible waveguide according to claim 1, wherein the flexible waveguide transmits a millimeter wave or a submillimeter wave of 60 GHz or higher. The flexible waveguide according to claim 2 or 3, further comprising an elastic tubular member disposed outside the outer conductor and the pressing member. The tubular member has a plurality of strips whose cross section perpendicular to the stretching direction exhibits a rectangular cross section,
In any of the plurality of strips, the flat portion of the strip is the external portion in a state where the side edge of the strip forms a predetermined angle with the longitudinal direction of the flexible waveguide. The flexible conductor according to claim 5, wherein the conductor and the pressing member extend so as to be wound around the outer peripheral surfaces of the conductor and the bands of the conductor and the pressing member are knitted so as to form a braid-like form. Wave tube. The flexible waveguide according to claim 5, wherein the tubular member is a tape member that extends so as to be wound around outer peripheral surfaces of the outer conductor and the pressing member. The flexible waveguide according to claim 5, wherein the tubular member is a rubber tube provided on the outer peripheral surfaces of the outer conductor and the pressing member and having heat shrinkability. The flexible waveguide according to any one of claims 2 to 8, wherein the pressing member is a hollow or solid member, an optical fiber, or an electric wire. The flexible waveguide according to claim 2, wherein the flexible linear member is a hollow or solid member, an optical fiber, or an electric wire. An image transmission device comprising the flexible waveguide according to claim 1.
The image transmission device, wherein the flexible waveguide transmits a predetermined image signal. An endoscope having the flexible waveguide according to any one of claims 1 to 10,
The endoscope, wherein the flexible waveguide transmits a predetermined image signal. The endoscope according to claim 12,
An image processing unit that performs predetermined image processing on a predetermined image signal transmitted by the flexible waveguide,
An endoscope system comprising:

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