Front end structure of endoscope

An endoscope having an inserted portion, which is to be inserted into a tubular organ, including a bendable portion that is adapted to bend arbitrarily by a remote operation and a distal unit with a window for observation to capture an image of inside the tubular organ, is provided. A plurality of grooves are formed in parallel with an axis of the distal unit on a circumferential surface of the distal unit and the grooves are spaced from each other.

BACKGROUND OF THE INVENTION

The present invention relates to an endoscope to be inserted into a tubular organ including a large intestine.

When an endoscope is inserted into a tubular organ such as a large intestine through an anus, an inserted portion of the endoscope proceeds in the winding intestine through a relatively short rectum, an S-shaped sigmoid colon with a small curvature, a descending colon and a traverse colon until the inserted portion reaches to an ascending colon. Specifically, a part of the intestine between the descending colon and the traverse colon is bent at an angle that is generally sharper than the right angle, therefore it has been difficult for operators to insert the endoscope deeply in the colons.

In addition, most part of the colons is movable in a body cavity and not held to a body wall, thus the colons, specifically the sigmoid colon, are easily elongated, shortened or deformed by external force. Therefore, even if the endoscope is forcibly inserted into the colons, the colons are merely elongated by the inserted portion, and the inserted portion is not effectively advanced deeply in the colons.

In consideration of the above problems, when the inserted portion is inserted in the colons and advanced to an extent, a bendable portion of the endoscope, which is configured at a distal end of the inserted portion, is bent at a small curvature by a remote operation from the operator, and the distal end is pressed and hooked to a creased portion of an inner wall of the colon. With the distal end hooked to the crease, the inserted portion is twisted in a circumferential direction along with the inserted portion, thus the colon is turned to be partially straightened so that the inserted portion can be advanced further with respect to the colon.

Such an endoscope for a large intestine with the inserted portion and the bendable portion is generally provided with an observation window at the distal end for capturing an image of an object, which is ahead of the inserted portion. In such case, the inserted portion is often provided further with a hood that protrudes from an outer edge of the inserted portion to prevent the observation window from directly being in contact with an intestinal wall. An example of such an endoscope is disclosed in Japanese Patent Provisional Publication HEI10-248792. In recent years, there are also provided with endoscopes having observation windows and no hoods. An example of such an endoscope is disclosed in Japanese Patent Provisional Publication 2002-125915.

When an endoscope as described above is inserted into the colons and twisted to partially straighten the colon, the bendable portion hooked to the crease may slip and be unhooked from the crease unintentionally. In such case, the operator is required to repeat the hooking and twisting operations, which consume time and may be troublesome.

SUMMARY OF THE INVENTION

Aspects of the present invention are advantageous in that an endoscope having an inserted portion, which is to be inserted into a tubular organ, including a bendable portion that is adapted to bend arbitrarily by a remote operation and a distal unit with a window for observation to capture an image of inside the tubular organ, is provided. A plurality of grooves are formed in parallel with an axis of the distal unit on a circumferential surface of the distal unit and the grooves are spaced from each other.

An outer diameter of the distal unit may be configured to be greater than an outer diameter of the bendable portion. A step may be formed at a boundary of the bendable portion and the distal unit. The circumferential surface of the distal unit may be provided with the plurality of grooves.

The circumferential surface of the distal unit may formed to be tapered. The circumferential surface of the distal unit may be provided with the plurality of grooves.

A cross-sectional shape of each of the plurality of grooves may be an arc.

Aspects of the present invention are advantageous in that an endoscope having an inserted portion, which is to be inserted into a tubular organ, including a bendable portion that is adapted to bend arbitrarily by a remote operation and a distal unit with a window for observation to capture an image of inside the tubular organ is provided. The distal unit is provided with a tubular hood that protrudes forwardly from an edge of the distal unit. A plurality of grooves are formed perpendicularly to a diameter of the hood and the grooves are spaced from each other.

An outer diameter of the hood may be configured to be greater than an outer diameter of the bendable portion. The circumferential surface of the hood may be provided with the plurality of grooves.

DETAILED DESCRIPTION OF THE EMBODIMENT

Referring to the accompanying drawings, an endoscope according to an embodiment of the invention will be described in detail.

First Embodiment

FIG. 4is an external view of an entire configuration of an endoscope1000according to a first embodiment of the present invention. The endoscope1000is provided with a flexible inserted portion1. The inserted portion1includes a bendable portion2in a vicinity to a distal end of the endoscope1000. The endoscope1000is further provided with an operation unit3that is attached to the proximal end of the inserted portion1and operation knobs4. The bendable portion2is configured to bend at an arbitrary curvature in an arbitrary direction, for example as shown in the dotted lines inFIG. 4, by an operation to the operation knobs4.

At the distal end of the endoscope1000, the bendable portion2is provided with an inflexible and short column-like distal unit5, in which various functional components for example an optical system and a solid-state image capturing element are installed. On an outer peripheral surface of the distal unit5, a plurality of grooves6, which are spaced from each other, are formed in parallel with an axial direction of the distal unit5.

FIG. 1is a side view of the inserted portion1with the distal unit5of the endoscope1000according to the first embodiment of the present invention, andFIG. 2is a perspective view of the inserted portion1and the distal unit5of the endoscope1000according to the first embodiment of the present invention. On a distal surface5aof the distal unit5, a plurality of windows including an observation window7and an illumination window8to capture an image of an object are provided, so that the operator can observe inside of the colons.

An outer diameter D5of the distal unit5is configured to be greater than an outer diameter D2of the bendable portion2(more specifically, the diameter of the bendable portion2at the closest to the distal unit5). Therefore, a step S is circumferentially formed at a boundary between the distal unit5and the bendable portion2. A depth t of the step S is for example in a range from 0.5 mm to 2 mm.

FIG. 3is a cross-sectional view of the distal unit5of the endoscope1000taken along the line III-III inFIG. 1. As shown inFIG. 3, evenly spaced eight grooves6are formed on the outer peripheral surface of the distal unit5, although the grooves6are not necessarily spaced evenly from each other. Each groove6is curved to have a cross-sectional shape of an arc. However, it should be noted that the cross sectional shape of each groove6is not limited to an arc. A depth of each groove6from the outer peripheral surface of the distal unit5is configured to be substantially equal to the depth t of the step S. It should be also noted that the number of the grooves6is not limited to eight, but is preferable to be in a range from three to twelve for practical reasons.

FIG. 5is an illustrative view of the endoscope1000in use according to the first embodiment of the present invention. The bendable portion2with the distal unit that passed by a crease100is bent by a remote operation, and the grooves6of the distal unit5are pressed and hooked to a back surface of the crease100.

FIG. 6is another illustrative view of the endoscope1000in use according to the first embodiment of the present invention. With the grooves6hooked to the crease100, when the inserted portion1is twisted in the circumferential direction, for example as indicated by an arrow inFIG. 6, the looped colon is turned along with the inserted portion1to be partially straightened. In addition, the crease100hooked with an edge of the step S can be pulled toward the anus, thus the colon toward the anus can be partially shortened, and the trailed part of the colon is straightened, so that the inserted portion1can be further advanced with respect to the colon.

In the above-described operation, the distal unit5with the grooves6of the endoscope of the present invention is firmly hooked to the crease100, and the distal unit5is less likely to be detached from the crease100. Therefore, the colons are effectively straightened and the inserted portion1can be securely advanced in the colons.

Second Embodiment

FIG. 7is a side view of the inserted portion11of an endoscope1001according to a second embodiment of the present invention. A circumferential surface of a distal unit51in the second embodiment is configured to be tapered with an outer diameter at an distal end of the distal unit51being smaller than an outer diameter D5′ at a boundary between the distal unit51and an inserted portion11. With this configuration, inserting the distal unit51in the colons becomes easier than inserting the distal unit5of the first embodiment. The remaining configuration of the endoscope1001is similar to the configuration of the first embodiment.

Third Embodiment

FIG. 8is a partially cross-sectional view of an inserted portion12of an endoscope1002according to a third embodiment of the present invention. A hood10is detachably attached to a distal unit52. The hood10may be attached to the distal unit52by being elastically tightened, engaged by an engaging structure including a pair of an engaging protrusion and a mating recessed portion, screwed to the distal unit52, or in other known configurations. The hood10is configured to protrude forwardly from an edge of the distal unit52.

On a circumferential surface of the hood10, a plurality of grooves61, are formed perpendicularly to a diameter of the hood10and spaced from each other. Each of the grooves61is curved to have a cross-sectional shape of an arc. However, it should be noted that the cross sectional shape of each groove61is not limited to an arc. Further, an outer diameter D10of the hood10is configured to be greater than an outer diameter D2of the bendable portion2. With this configuration, the endoscope1002is capable of effectively straightening the colons and is securely advanced in the colons. The hood10may be formed with a transparent material, in which case a scope for observation is not intercepted by the hood10.

The present disclosure relates to the subject matter contained in Japanese Patent Application No. 2005-006979, filed on Jan. 14, 2005, which is expressly incorporated herein by reference in its entirety.