Waveguide, image transmission apparatus including waveguide, endoscope including waveguide, and endoscope system

Patent metadata

Field	Value
Publication number	US-11045069-B2
Application number	US-201916672396-A
Country	US
Kind code	B2
Filing date	Nov 1, 2019
Priority date	May 2, 2017
Publication date	Jun 29, 2021
Grant date	Jun 29, 2021

Abstract

A flexible waveguide includes an inner dielectric, and a flexible external conductor disposed in a position covering an outer periphery of the dielectric, the flexible waveguide conducting a radio wave in a frequency band equal to or longer than a millimeter wave or a submillimeter wave near 60 GHz or more. The external conductor includes a metal layer, the metal layer has a shape displacement structure, a shape of an inner periphery side section of which faces the inner dielectric and is cyclic in the waveguide longitudinal direction, the shape displacement structure being a cyclic structure satisfying λmr<λch, where λmr represents a center wavelength of a main reflection band due to the cyclic structure and λch represents a cutoff wavelength in a high-order mode of the waveguide.

First claim

What is claimed is:

1. A waveguide comprising:
a linear dielectric, a dielectric constant of which is uniform in a longitudinal direction and a cross section of which assumes a same shape in the longitudinal direction; and
an external conductor disposed in a position covering an outer periphery of the dielectric and comprising a tube having flexibility,
wherein:
the waveguide conducts a radio wave in a frequency band equal to or higher than a frequency band of a millimeter wave or a submillimeter wave near 60 GHz or higher,
the external conductor includes a metal layer,
the metal layer has a cyclic structure, a shape of an inner periphery side section of the metal layer facing the dielectric and forming a cyclic shape displacement member in the waveguide longitudinal direction,
the cyclic structure is a structure satisfying λmr<λch, where λmr represents a center wavelength of a main reflection band due to the cyclic structure and λch represents a cutoff wavelength in a high-order mode of the waveguide, and
the cyclic structure is a structure in which a cycle L in the waveguide longitudinal direction of the shape displacement member in the cyclic structure satisfies L<λc/(4×√εr), where λc represents a cutoff wavelength in a basic mode of the waveguide and εr represents a specific dielectric constant of the dielectric.

2. The waveguide according to claim 1 , wherein:
the metal layer has a bellows shape in which a cyclic unevenness section is formed in the waveguide longitudinal direction, and
the cyclic structure is a structure in which a minimum cycle L relating to the cyclic unevenness section in the bellows shape in the cyclic structure satisfies L<λc/(4×√εr), where λc represents the cutoff wavelength in the basic mode of the waveguide and εr represents the specific dielectric constant of the dielectric.

3. An image transmission apparatus comprising the waveguide according to claim 1 , wherein the waveguide transmits a predetermined image signal.

4. An endoscope comprising the waveguide according to claim 1 , wherein the waveguide transmits a predetermined image signal.

5. An endoscope system comprising:
the endoscope according to claim 4 ; and
an image-signal processing circuit configured to apply predetermined image processing to the predetermined image signal transmitted by the waveguide.

6. A waveguide comprising:
a linear dielectric, a dielectric constant of which is uniform in a longitudinal direction and a cross section of which assumes a same shape in the longitudinal direction; and
an external conductor disposed in a position covering an outer periphery of the dielectric and comprising a tube having flexibility,
wherein:
the waveguide conducts a radio wave in a frequency band equal to or higher than a frequency band of a millimeter wave or a submillimeter wave near 60 GHz or higher,
the external conductor includes a metal layer,
the metal layer has a cyclic structure, a shape of an inner periphery side section of the metal layer facing the dielectric and forming a cyclic shape displacement member in the waveguide longitudinal direction,
the cyclic structure is a structure satisfying λmr<λch, where λmr represents a center wavelength of a main reflection band due to the cyclic structure and λch represents a cutoff wavelength in a high-order mode of the waveguide,
the metal layer comprises at least one belt-like member including a metal substance, a cross section of the belt-like member perpendicular to an extending axis assuming a rectangular cross section,
the belt-like member extends such that, in a state in which a side edge portion of the belt-like member forms a predetermined angle with respect to the waveguide longitudinal axis, a flat section of the belt-like member is wound on an outer peripheral surface of the dielectric, and the belt-like member is disposed such that side edge portions facing each other in adjacent winds of the belt-like member keep a constant interval in the waveguide longitudinal direction, and
the cyclic structure is a structure satisfying (s+p)/cos θ<λc/(4×√εr), where λc represents the cutoff wavelength in the basic mode of the waveguide, εr represents the specific dielectric constant of the dielectric, s represents a width of the belt-like member, p represents the constant interval, and θ represents the predetermined angle with respect to the waveguide longitudinal axis at a time when an angle orthogonal to the waveguide longitudinal axis is set to 0 degrees.

7. A waveguide comprising:
a linear dielectric, a dielectric constant of which is uniform in a longitudinal direction and a cross section of which assumes a same shape in the longitudinal direction; and
an external conductor disposed in a position covering an outer periphery of the dielectric and comprising a tube having flexibility,
wherein:
the waveguide conducts a radio wave in a frequency band equal to or higher than a frequency band of a millimeter wave or a submillimeter wave near 60 GHz or higher,
the external conductor includes a metal layer,
the metal layer has a cyclic structure, a shape of an inner periphery side section of the metal layer facing the dielectric and forming a cyclic shape displacement member in the waveguide longitudinal direction,
the cyclic structure is a structure satisfying λmr<λch, where λmr represents a center wavelength of a main reflection band due to the cyclic structure and λch represents a cutoff wavelength in a high-order mode of the waveguide,
the metal layer comprises a plurality of belt-like members including a metal substance, a cross section of each of the belt-like members perpendicular to an extending axis assuming a rectangular cross section,
the plurality of belt-like members extend, in a state in which side edge portions of all the belt-like members form a predetermined angle with respect to the waveguide longitudinal axis, such that flat sections of the belt-like members are wound on an outer peripheral surface of the dielectric and the plurality of belt-like members are composed arranged to form a braid-like form with one another, and
the cyclic structure is a structure satisfying (L1z/M)<λc/(4×√εr), where λc represents the cutoff wavelength in the basic mode of the waveguide, εr represents the specific dielectric constant of the dielectric, L1z represents an entire peripheral dimension of the waveguide cross section, and M represents a number of the belt-like members used to form the braid-like form.

8. The waveguide according to claim 7 , wherein the belt-like member comprises one of (i) a film comprising a resin film and metal, and (ii) a yarn including a foil.

9. A waveguide comprising:
a linear dielectric, a dielectric constant of which is uniform in a longitudinal direction and a cross section of which assumes a same shape in the longitudinal direction; and
an external conductor disposed in a position covering an outer periphery of the dielectric and comprising a tube having flexibility,
wherein:
the waveguide conducts a radio wave in a frequency band equal to or higher than a frequency band of a millimeter wave or a submillimeter wave near 60 GHz or higher,
the external conductor includes a metal layer,
the metal layer has a cyclic structure, a shape of an inner periphery side section of the metal layer facing the dielectric and forming a cyclic shape displacement member in the waveguide longitudinal direction,
the cyclic structure is a structure satisfying λmr<λch, where λmr represents a center wavelength of a main reflection band due to the cyclic structure and λch represents a cutoff wavelength in a high-order mode of the waveguide, and
the cyclic structure is a structure satisfying λsr>λc or λsr<λch, where λsr represents a center wavel

Assignees

• Olympus Corp

Inventors

• Ito Keigo
• Watanabe Tadashi

Classifications

• A61B1/00009 Primary

  of image signals during a use of endoscope · CPC title

• A61B1/00013 Primary

  using optical means · CPC title

• H01P3/122

  Dielectric loaded (not air) · CPC title

• A61B1/051

  Details of CCD assembly · CPC title

• H01P3/14

  flexible · CPC title