Patent Description:
An endoscope device generally includes an insertion portion to be inserted into a body (such as a digestive organ) of a subject. The insertion portion includes a light guide configured for transmission of light and an electrical wiring for transmission of an electrical signal from an imaging unit. In addition, the insertion portion includes a channel configured for water supply or air supply, and a treatment instrument channel configured for insertion and removal a treatment instrument therein.

The insertion portion of the endoscope is required to flexibly change its shape in the body of the subject. For this reason, it is desirable that various channels included inside the insertion portion also have high pliability.

However, if the pliability of a channel increases, the possibility that buckling occurs in the channel increases. Further, in the case of the treatment instrument channel, an inner wall may be scraped by insertion and removal of the treatment instrument so that the channel may be broken. For this reason, for example, in endoscopes disclosed in Patent Literatures <NUM> and <NUM>, a treatment instrument channel has a two-layer structure in which an inner layer is made of polytetrafluoroethylene (PTFE) having a solid structure and an outer layer is made of PTFE having a porous structure.

Meanwhile, the insertion portion of the endoscope generally includes a bending section, which can be actively bent by an operation of an operator, at a distal end. Further, the insertion portion also includes a flexible tube portion that is passively bent regardless of the operation of the operator, for example, when a distal end portion abuts on a wall surface of a digestive organ. In this manner, the insertion portion has the bending section capable of the active bending operation and the flexible tube portion in which only the passive bending operation occurs, and thus, it is easy to capture an image of an arbitrary point inside the digestive organ. Note that the flexible tube portion is sometimes further divided into a plurality of portions having different degrees of bending.

In this manner, the conventional endoscope includes the bending section capable of the active bending operation and the flexible tube portion in which the passive bending operation occurs. In the conventional endoscope, however, the degree of pliability of the treatment instrument channel is substantially uniform over the entire length of the bending section and the insertion portion. For this reason, there may be a case where it is difficult to obtain an expected operation without sufficiently obtaining the degree of pliability of the flexible tube portion. Conversely, if the degree of pliability of the channel in the bending section is high, the breakage of the channel including buckling of the channel or the like sometimes occurs.

An object of the present invention is to provide an endoscope capable of effectively suppressing breakage of a channel while sufficiently exhibiting performance of a plurality of portions having different degrees of bending.

In order to solve the above problems, an endoscope according to the present invention includes an insertion portion and a channel arranged inside the insertion portion. The insertion portion includes a bending section that is bendable based on an operation, and a flexible tube portion that is bendable by an external force unrelated to the operation. The channel includes an inner layer and an outer layer formed outside the inner layer, the inner layer is made of polytetrafluoroethylene having a solid structure, and the outer layer is made of polytetrafluoroethylene having a porous structure. A porosity of the outer layer in the bending section is smaller than a porosity of the outer layer in the flexible tube portion.

According to the endoscope of the present invention, it is possible to provide the endoscope capable of effectively suppressing the breakage of the channel while sufficiently exhibiting the performance of the plurality of portions having different degrees of bending.

Hereinafter, the present embodiments will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements may be represented by the same number. Note that the accompanying drawings illustrate embodiments and implementation examples conforming to principles of the present disclosure, but these are for understanding of the present disclosure and are not used to interpret the present disclosure in a limited manner. The description in this specification is merely exemplary and is not intended to limit the significance of the claims or applications of the present disclosure in any way.

The present embodiments have been described in sufficient detail to enable those skilled in the art to practice the present disclosure, but it should be understood that other implementations and modes may be made and that modifications in configurations and structures and replacements of various elements are possible without departing from the scope and spirit of the technical idea of the present disclosure. Therefore, the following description should not be interpreted as being limited thereto.

First, an endoscope system according to an embodiment of the present invention will be described in detail. <FIG> is an exterior view of an endoscope system <NUM> according to the first embodiment, and <FIG> is a perspective view illustrating a structure of a distal end portion <NUM> of an endoscope <NUM>. The endoscope system <NUM> generally includes the endoscope <NUM>, a processor <NUM>, alight source device <NUM>, a water/air supply unit <NUM>, a suction unit <NUM>, a display <NUM>, and an input unit <NUM>.

The endoscope <NUM> is configured to be insertable into a body of an object and has a function of capturing an image of a subject and transmitting an image signal of the captured image to the processor <NUM>. The processor <NUM> receives the image signal from the endoscope <NUM> and performs predetermined signal processing.

The light source device <NUM> is configured to be connectable to the processor <NUM>, and includes a light source that emits irradiation light configured for irradiation of the object therein. The light from the light source is emitted toward the subject through a light guide to be described later. The light source device <NUM> may be configured separately from the processor <NUM> and connectable to the processor <NUM>, or may be incorporated in the processor <NUM>.

The water/air supply unit <NUM> includes an air pump configured to discharge a water flow or an air flow supplied to the subject. The suction unit <NUM> includes a pump and a tank (not illustrated) configured to suck a body fluid and an excised material sucked from the body of the subject through the endoscope <NUM>.

The display <NUM> is a display device configured to perform display based on, for example, a data processing result in the processor <NUM>. Further, the input unit <NUM> is a device configured to input instructions from an operator in various measurement operations.

The endoscope <NUM> includes an insertion portion <NUM>, a hand operation unit <NUM>, a universal cable <NUM>, and a connector unit <NUM>. The insertion portion <NUM> further includes a flexible tube portion <NUM>, a connecting portion 103A, a bending section <NUM>, and a distal end portion <NUM>.

As illustrated in <FIG>, the insertion portion <NUM> of the endoscope <NUM> includes the flexible tube portion <NUM> which has flexibility and is configured to be inserted into the body of the subject. The flexible tube portion <NUM> is connected to the hand operation unit <NUM> at one end thereof. The hand operation unit <NUM> includes, for example, a bending operation knob 102A and other operation units that can be operated by a user, and is a portion configured to allow the operator to perform various operations for imaging by the endoscope system <NUM>. Note that the hand operation unit <NUM> is provided with a treatment instrument insertion port 102B for insertion of a treatment instrument.

In the flexible tube portion <NUM>, a portion close to the bending section <NUM> is a first flexible tube portion 101A, and a portion close to the hand operation unit <NUM> is a second flexible tube portion 101B. A shape of the bending section <NUM> can be actively changed by the operation of the bending operation knob 102A by the operator, but the first flexible tube portion 101A is a portion whose shape is passively changed due to an external force unrelated to the operation of the bending operation knob 102A, for example, an external force caused by the distal end portion <NUM> or the bending section <NUM> abutting on a wall surface of a digestive organ. The same also applies to the second flexible tube portion 101B, but the degree of change in shape is smaller (the maximum curvature radius is larger) than that of the first flexible tube portion 101A. Note that the flexible tube portion <NUM> has two types of flexible tube portions in the example of <FIG>, but the present invention is not limited thereto, and three or more types of flexible tube portions may be provided, or one type may be provided.

The bending section <NUM> (active bending section) configured to be bendable is provided at a distal end of the flexible tube portion <NUM>. As described above, the bending section <NUM> is bent by pulling an operation wire (not illustrated in <FIG>) in conjunction with a rotation operation of the bending operation knob 102Aprovided in the hand operation unit <NUM>. Note that the connecting portion 103A that is not deformed by a bending wire W or the external force may be provided between the bending section <NUM> and the first flexible tube portion 101A.

Furthermore, the distal end portion <NUM> including an image sensor (imaging unit) is connected to a distal end of the bending section <NUM>. As a direction of the distal end portion <NUM> changes according to a bending operation of the bending section <NUM> caused by the rotation operation of the bending operation knob 102A, it is possible to change an imaging area of the endoscope <NUM>.

The universal cable <NUM> extends from the opposite side of the hand operation unit <NUM> to the connector unit <NUM>. The universal cable <NUM> includes a light guide, various wirings, and various channels therein, which is similar to the insertion portion <NUM>.

The connector unit <NUM> includes various connectors configured to connect the endoscope <NUM> to the processor <NUM>. Further, the connector unit <NUM> includes a water/air supply channel <NUM> as a path configured to send a water flow and an air flow toward the insertion portion <NUM>.

A structure of the distal end portion <NUM> of the endoscope <NUM> will be described with reference to <FIG>. Light distribution lenses 112A and 112B are arranged at the distal end portion <NUM> of the endoscope <NUM>, and light guides LGa and LGb extend from the distal end portion <NUM> to the connector unit <NUM> inside the insertion portion <NUM>. Light from the light source of the light source device <NUM> is guided by the light guides LGa and LGb, and is emitted toward the subject by the light distribution lenses 112A and 112B arranged at the distal end portion <NUM>.

Further, as illustrated in <FIG>, the endoscope <NUM> includes an objective lens <NUM> and an image sensor <NUM> at the distal end portion <NUM>. The objective lens <NUM> provided at the distal end portion <NUM> collects scattered light or reflected light from the subject to form an image of the subject on a light receiving surface of the image sensor <NUM>.

As an example, the image sensor <NUM> can be configured using a charge coupled device (CCD) or a complementary metal oxide semiconductor sensor (CMOS sensor). The image sensor <NUM> is controlled by signals (a gain control signal, an exposure control signal, a shutter speed control signal, and the like) supplied from the processor <NUM> through an electrical wiring <NUM>, and supplies an image signal of a captured image to the processor <NUM> through the electrical wiring <NUM> and an A/D conversion circuit (not illustrated).

Further, an air/water supply port <NUM>, an auxiliary water supply port <NUM>, and a treatment instrument port <NUM> are provided, as end portions or openings of various channels, on an end surface of the distal end portion <NUM>. The air/water supply port <NUM> (nozzle) is connected to an air/water supply channel <NUM> to introduce a water flow or an air flow for cleaning or the like of the distal end portion <NUM>.

Further, the auxiliary water supply port <NUM> is connected to an auxiliary water supply channel <NUM> to introduce the auxiliary water supply for removing dirt in the visual field. The channels <NUM> to <NUM> are arranged so as to extend along the inside of the distal end portion <NUM>, the bending section <NUM>, the insertion portion <NUM>, the hand operation unit <NUM>, and the universal cable <NUM>.

In addition to the channels <NUM> to <NUM>, a treatment instrument channel <NUM> is provided inside the endoscope <NUM>. A treatment instrument such as forceps is arranged inside the treatment instrument channel <NUM> so as to freely advance and retreat. A distal end of the treatment instrument channel <NUM> forms the treatment instrument port <NUM> at the distal end portion <NUM>. Note that the treatment instrument channel <NUM> may also serve as a suction channel.

A cross-sectional structure of the distal end portion <NUM> will be described in more detail with reference to <FIG>. This cross-sectional view illustrates details of structures of the objective lens <NUM> to the electrical wiring <NUM>, the air/water supply channel <NUM>, and the treatment instrument channel <NUM>. Structures of the light distribution lenses 112A and 112B and the light guides LGa and LGb are not illustrated. Further, a structure of the auxiliary water supply channel <NUM> is not illustrated either.

The distal end portion <NUM> has a distal-end rigid portion <NUM>. The distal-end rigid portion <NUM> includes holes respectively forming the air/water supply port <NUM>, the auxiliary water supply port <NUM>, and the treatment instrument port <NUM> described above. As illustrated in <FIG>, the air/water supply channel <NUM> and the treatment instrument channel <NUM> are inserted into corresponding holes of the distal-end rigid portion <NUM>.

The distal-end rigid portion <NUM> also has a hole configured for fitting of a lens frame <NUM> that holds the objective lens <NUM>, an aperture AP, and alight shielding mask <NUM>. The lens frame <NUM> is fixed to the hole of the distal-end rigid portion <NUM> with a sealant <NUM> interposed therebetween.

Meanwhile, as an example, the light shielding mask <NUM>, a cover glass <NUM>, the image sensor (CCD) <NUM>, and a circuit board <NUM> are held by a CCD unit frame <NUM> on the rear side of the objective lens <NUM>, and the CCD unit frame <NUM> is inserted and fixed to the hole of the distal-end rigid portion <NUM>. The electrical wiring <NUM> is connected to the circuit board <NUM>.

The distal end portion <NUM> (distal-end rigid portion <NUM>) configured as described above is fitted into the distal end of the bending section <NUM>. The bending section <NUM> is formed by rotatably connecting bending pieces <NUM> each of which is formed in a substantially cylindrical shape to each other by a rivet. An outer surface of the bending piece <NUM> is covered with a reticular tube <NUM>. The reticular tube <NUM> is joined to the distal-end rigid portion <NUM> at its end portion through an annular joining tube <NUM>. Further, an outer surface of the reticular tube <NUM> is covered with an outer rubber tube <NUM> made of a synthetic resin. The outer rubber tube <NUM> and the distal-end rigid portion l04M are fixed at end portions thereof by, for example, a fixing yarn S1.

A wire guide <NUM> is provided between the plurality of bending pieces <NUM>, and the bending wire W for the bending operation passes through the wire guide <NUM>. For example, four bending wires W are provided at substantially equal intervals in the circumferential direction in one insertion portion <NUM>. One end of each of the bending wires W is fixed to the foremost bending piece <NUM>. The other end of the bending wire W is tensioned and relaxed by the operation of the bending operation knob 102A, whereby the bending section <NUM> is bent.

Next, structures of the connecting portion 103A, the first flexible tube portion 101A, and the second flexible tube portion 101B will be described with reference to <FIG>.

As described above, the connecting portion 103A is a member that connects the bending section <NUM> and the first flexible tube portion 101A, and is a rigid portion whose outer shape is not deformed by the operation of the bending wire W or the external force. The first flexible tube portion 101A includes a plurality of bending pieces 153A, which is similar to the bending section <NUM>. The bending pieces 153A are rotatably connected to each other by a rivet, which is similar to the bending pieces <NUM> Further, as an example, the second flexible tube portion 101B may include a spiral tube 153B (flat coil made of metal), a metal mesh 153C, and an outer resin 153D (polyurethane or the like) from the inside.

Further, the first flexible tube portion 101A and the second flexible tube portion 101B are provided with a coil sheath <NUM> configured to allow the bending wire W extending from the hand operation unit <NUM> to pass therethrough. The bending wire W is arranged so as to be slidable inside the coil sheath <NUM>, and thus, the shapes of the first flexible tube portion 101A and the second flexible tube portion 101B do not change even when the bending wire W is tensioned or relaxed. The first flexible tube portion 101A and the second flexible tube portion 101B can be deformed within a movable range of the bending piece 153A and the spiral tube 153B by the external force or the like caused by, for example, the outer wall of the digestive organ abutting on the insertion portion <NUM>.

As described above, the bending section <NUM>, the first flexible tube portion 101A, and the second flexible tube portion 101B can be deformed by the operation of the bending wire W or the external force, but the deformation limits (maximum curvature radii) are different from each other. Further, since the maximum curvature radii are different, buckling strengths (kink resistances) required for tubes for channels inserted therein are also different from each other.

In the first embodiment, the treatment instrument channel <NUM> is configured as illustrated in <FIG> such that characteristics of the bending section <NUM>, the first flexible tube portion 101A, and the second flexible tube portion 101B can be maximized. <FIG> is a cross-sectional view illustrating a cross-sectional structure of the treatment instrument channel <NUM> and a graph illustrating a characteristic (porosity Rah) thereof.

The treatment instrument channel <NUM> has a two-layer structure of an inner layer <NUM> and an outer layer <NUM> arranged outside the inner layer <NUM>. The inner layer <NUM> is made of PTFE having a solid structure over the entire length (the distal end portion <NUM> to the second flexible tube portion 101B) in order to suppress breakage due to contact with the treatment instrument passing through the channel. On the other hand, the outer layer <NUM> is made of porous PTFE. The PTFE having the solid structure is hard and has a high resistance to breakage, but is easily buckled, whereas the porous PTFE is flexible and has a low resistance to breakage, but is hardly buckled. Since the treatment instrument channel <NUM> has the two-layer structure of the PTFE having the solid structure and the porous PTFE, both the resistance to breakage and buckling resistance can be achieved. In other words, the PTFE having the solid structure of the inner layer <NUM> is held by the porous PTFE of the outer layer <NUM> that is hardly buckled, so that a tube that is flexible but hardly buckled can be obtained.

In addition, the porous PTFE of the outer layer <NUM> of the first embodiment has a different porosity Rah depending on a location. When the porosity Rah of the outer layer <NUM> is large, the pliability of the treatment instrument channel <NUM> is enhanced accordingly.

The outer layer <NUM> located in the bending section <NUM> that is bendable by the bending operation knob 102A has q porosity Rah set to about <NUM> to <NUM>%, for example. On the other hand, the outer layer <NUM> located in the first flexible tube portion 101A and the second flexible tube portion 101B has a higher porosity Rah (for example, <NUM> to <NUM>% which is a value higher than that of the inside of the bending section <NUM>) than the inside of the bending section <NUM>.

Since the degree of bending of the bending section <NUM> can be adjusted by operating the bending wire W with the bending operation knob 102A, the bending section <NUM> does not need to have a higher pliability than that of the insertion portion <NUM>. Therefore, it is sufficient for the outer layer <NUM> in the bending section <NUM> to have pliability to such an extent that the operation of the bending wire W is not hindered.

On the other hand, a curvature change larger than that of the insertion portion <NUM> is given to the bending section <NUM> by the bending wire W, and thus, it is required to suppress the breakage of the channel due to buckling. For this reason, the outer layer <NUM> of the treatment instrument channel <NUM> inside the bending section <NUM> is provided with a smaller porosity than those of the first flexible tube portion 101A and the second flexible tube portion 101B. As a result, the bending section <NUM> has pliability to such an extent that the bending wire W can be deformed, and has a high resistance to the buckling.

On the other hand, the first flexible tube portion 101A and the second flexible tube portion 101B need to be flexibly deformed by the external force based on abutment of the distal end portion <NUM> or the like on the inner wall of the digestive organ or the like, and to have a higher pliability than that of the bending section <NUM> in order reduce burden on a patient. The outer layer <NUM> of the treatment instrument channel <NUM> of the first embodiment is provided with a higher porosity Rah inside the first flexible tube portion 101A and the second flexible tube portion 101B than inside the bending section <NUM>. As a result, the first flexible tube portion 101A and the second flexible tube portion 101B are provided with a high pliability, and the burden on the patient is reduced. Note that the porosities Rah of the first flexible tube portion 101A and the second flexible tube portion 101B are the same in the above example, but different porosities may be given.

Note that the porosity Rah of the outer layer <NUM> inside the distal end portion <NUM> is arbitrary, and may be, for example, the same as the porosity Rah inside the bending section <NUM>. Since the distal end portion <NUM> is not bent (deformed), the hardness of the treatment instrument channel <NUM> passing through the distal end portion is irrelevant. Only the outer layer <NUM> of the distal end portion <NUM> may be made of the PTFE having the solid structure.

As described above, in the endoscope of the first embodiment, the treatment instrument channel <NUM> has the two-layer structure of the inner layer <NUM> and the outer layer <NUM>, the inner layer <NUM> is made of polytetrafluoroethylene having a solid structure, the outer layer <NUM> is made of polytetrafluoroethylene having a porous structure, and the porosity of the outer layer <NUM> in the bending section <NUM> is smaller than the porosity of the outer layer <NUM> in the first flexible tube portion 101A and the second flexible tube portion 101B. As a result, a certain degree of pliability and a sufficient buckling resistance can be obtained in the bending section <NUM>, while a high pliability can be obtained in the first flexible tube portion 101A and the second flexible tube portion 101B. Therefore, it is possible to provide the endoscope that sufficiently exhibits the functions of the flexible tube portion <NUM> and the bending section <NUM>. Note that the two-layer structure is adopted for the treatment instrument channel <NUM> in the above-described example, but it goes without saying that a similar structure may be adopted for a channel other than the treatment instrument channel <NUM>.

Next, an endoscope according to a second embodiment will be described with reference to <FIG>. The overall configuration of the endoscope of the second embodiment is similar to that of the first embodiment (<FIG>). Further, configurations of the distal end portion <NUM>, the bending section <NUM>, and the insertion portion <NUM> are also similar to those of the first embodiment (<FIG>) except for the following points.

The second embodiment is similar to the first embodiment in that the porosity Rah of the outer layer <NUM> inside the bending section <NUM> is smaller than the porosity Rah of the outer layer <NUM> inside the flexible tube portion <NUM>. However, the porosity Rah of the bending section <NUM> is set to a low value on the distal end portion <NUM> side, gradually increases at an end portion of the bending section <NUM> on the first flexible tube portion 101A side, and becomes substantially the same as the porosity Rah inside the first flexible tube portion 101A in the vicinity of a boundary between the bending section <NUM> and the flexible tube portion <NUM>. Note that the porosity Rah of the outer layer <NUM> inside the distal end portion <NUM> may be substantially the same as the porosity Rah inside the bending section <NUM> as in the first embodiment, but may be a value larger than the porosity Rah inside the bending section <NUM> as illustrated in <FIG>. Note that the boundary between the bending section <NUM> and the flexible tube portion <NUM> does not need to be strictly defined, and can be set at any location in the connecting portion 0103A.

According to the configuration of the second embodiment, the function of the bending section <NUM> can be further enhanced. In the bending section <NUM>, typically, a curvature is small at the end portion on the distal end portion <NUM> side, and the curvature is large on the flexible tube portion <NUM> side. For this reason, when the distribution of the porosity Rah as illustrated in <FIG> is adopted inside the bending section <NUM>, a buckling resistance can be enhanced at the end portion of the bending section <NUM> on the distal end portion <NUM> side, and pliability can be enhanced on the insertion portion <NUM> side.

Claim 1:
An endoscope comprising:
an insertion portion; and
a channel arranged inside the insertion portion,
wherein the insertion portion includes:
a bending section that is bendable based on an operation; and
a flexible tube portion that is bendable by an external force unrelated to the operation,
the channel includes an inner layer and an outer layer formed outside the inner layer,
the inner layer is made of polytetrafluoroethylene having a solid structure,
the outer layer is made of polytetrafluoroethylene having a porous structure, characterized in that
a porosity of the outer layer in the bending section is smaller than a porosity of the outer layer in the flexible tube portion.