An endoscope includes: an observation window disposed in a distal end portion of an insertion portion; a nozzle disposed in the distal end portion; and a cover configured to cover the distal end portion, a distal end surface of the cover includes: a first surface surrounding the observation window, the first surface having a first planar shape when viewed in a cross-section taken about a line connecting the observation window and the nozzle; a second surface disposed radially outside the first surface, the second surface having a curved shape when viewed in the cross-section; and a third surface disposed radially outside of the second surface, the third surface having a second planar shape.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to an endoscope including a distal end cover in a distal end portion of an insertion portion.

2. Description of the Related Art

Japanese Patent Application Laid-Open Publication No. 2003-210388 discloses an endoscope in which a distal end cover provided on a distal end surface of an insertion portion includes an annular inclined portion surrounding an observation window and fluid is ejected toward the inclined portion from an air/water feeding nozzle.

SUMMARY

An endoscope of an embodiment of the present disclosure includes: an observation window disposed in a distal end portion of an insertion portion; a nozzle disposed in the distal end portion; and a cover that covers the distal end portion, in which a distal end surface of the cover includes: a first surface surrounding the observation window, the first surface having a first planar shape when viewed in a cross-section taken about a line connecting the observation window and the nozzle; a second surface disposed radially outside the first surface, the second surface having a curved shape when viewed in the cross-section; and a third surface disposed radially outside of the second surface, the third surface having a second planar shape.

DETAILED DESCRIPTION

Hereinafter, endoscopes of embodiments of the present disclosure will be described using the drawings. Note that in the following description, the drawings based on the embodiments are schematic illustrations. In the drawings, the relation between the thickness and the width of each portion, the ratio in thickness of each portion, and the like differ from the actual relation, ratio, and the like. There are also some portions with different dimensional relations and ratios among the drawings. Illustration of and assignment of reference signs to some of the components will be omitted in the drawings.

As shown inFIG.1, an endoscope system2includes an endoscope1, a light source device3, a video processor4, and a monitor5of an embodiment.

The endoscope1includes an insertion portion6to be inserted into a body cavity, an operation portion7, and a universal cord8. The insertion portion6is continuously provided with a distal end portion12, a bending portion13, and a flexible portion14in this order from the distal end side. The universal cord8is provided with a connector9connected to the light source device3, and an electric cable10connected to the video processor4extends from the connector9. An image pickup signal of an image picked up by the endoscope1is subjected to image processing by the video processor4and an endoscope image is displayed on the monitor5.

First Embodiment

FIG.2is a front view of the distal end portion12of the endoscope1of the embodiment as viewed from a side of a distal end surface. An observation window15including an objective lens, a channel opening16, illumination windows17,18, and an air/water feeding nozzle19are disposed on the distal end surface of the distal end portion12. The distal end portion12is covered by a distal end cover30including a plurality of openings respectively corresponding to the observation window15, the channel opening16, and the illumination windows17,18.

The observation window15is a forefront surface of an image pickup optical system15A including a lens holding member15B. An adhesive (not shown) may be disposed between the image pickup optical system15A and the lens holding member15B. In the drawings below, an outer surface15SA of the observation window15indicates the forefront surface including the image pickup optical system15A, the adhesive, and the lens holding member15B. In the air/water feeding nozzle19, an opening C19that ejects fluid in a direction toward the observation window15is disposed.

A distal end surface30SA of the distal end cover30includes an annular first area31(first surface) surrounding the observation window15, an annular second area32(second surface) in contact with the first area31on the inner circumference, and a third area33(third surface) in contact with an outer circumference of the second area32. The second area32is formed on an outer side of the first area31and the third area33is formed on an outer side of the second area32.

The third area33is a plane parallel to the outer surface15SA of the observation window15. The outer surface15SA of the observation window15projects by, for example, 0.3 mm relative to the third area33. In other words, there is a step between the third area33and the outer surface15SA of the observation window15. Therefore, the distal end cover30includes an inclined surface between the third area33and the outer surface15SA of the observation window15. The inclined surface is composed of the first area31as a first inclined surface (first planar shape) formed of a plane and the second area32as a second inclined surface formed of a curved surface.

FIG.3is a cross-sectional view taken along line III-III ofFIG.2, showing a cross-section from the air/water feeding nozzle19to the observation window15. As shown inFIG.3, the distal end portion12is provided with a distal end rigid member20on which the image pickup optical system15A and the like are disposed and the distal end cover30covers the top of the distal end rigid member20.

An inner circumference of the first area31(outer circumference of the observation window15), an outer circumference of the first area31(inner circumference of the second area32), and an inner circumference of the third area33are all circles concentric about a center C15of the observation window15.

The distal end cover30covers a part of an outer circumference surface of the distal end rigid member20as well as the distal end surface of the distal end rigid member20. A boundary area between the distal end surface30SA and an outer circumference surface30SS of the distal end cover30is a so-called outside rounded corner area chamfered with a curved surface.

Water ejected from the opening of the air/water feeding nozzle19in the direction toward the observation window15bumps against the first area31to be widely spread and flows over the entire outer surface15SA of the observation window15. The water flowing over the outer surface15SA of the observation window15converges, halfway in flowing down the first area31, to the extent that the width is at the same level as the width of the opening of the air/water feeding nozzle19.

However, there is a region where due to the step between the outer surface15SA of the observation window15and the third area33, it is difficult for the water ejected from the air/water feeding nozzle19to flow in the direction toward the observation window15along the inclined surface (second area32).

For example, after water feeding, the water is likely to remain in a lower portion of the step near the air/water feeding nozzle19. When air is fed to remove water droplets adhering to the outer surface15SA of the observation window15, the water remaining in the lower portion of the step is blown up by the fed air, thereby adhering to the observation window15. In other words, despite the air feeding to remove the water droplets adhering to the outer surface15SA of the observation window15, the water is resupplied to the outer surface15SA, which results in inefficient air feeding.

Further, when the water flowing over the outer surface15SA of the observation window15flows down to the third area33via the first area31as the inclined surface, the water droplets are likely to gather in the lower portion of the step. In an endoscope including an optical system with a wide angle of view, the water droplets could occasionally be seen on an image.

As shown inFIG.4, the distal end cover30of the endoscope1includes the second area32as an inside rounded corner area at a boundary between the first area31and the third area33. Therefore, water is unlikely to remain at the boundary between the first area31and the third area33. Accordingly, the air/water feeding of the endoscope1is efficient.

A width W31of the first area31and a width W32of the second area32are, for example, around 1 mm. For example, the width W31of the first area31is a length of the first area31in a direction along the shortest line connecting the center C15of the observation window15and the first area31.

Since the distal end cover30includes the second area32formed of a curved surface with a radius of curvature R32of more than 0.5 mm, generation of the remaining water is prevented. Note that in order to prevent the outer diameter of the distal end portion12of the endoscope1from being enlarged, the radius of curvature R32of the second area32is preferably less than 2 mm.

Note that the inside rounded corner area is occasionally formed between the first area31that is a plane as an inclined surface and the third area33that is a plane as a flat surface (second planar shape). The inside rounded corner area has the small radius of curvature R32, thereby having a small effect of prevention of remaining water generation, but is included in the second area.

Note that as denoted by a broken line inFIG.4, the outside rounded corner area may be formed between the first area31and the outer surface15SA of the observation window15.

Modifications of First Embodiment

Endoscopes1A to1F of modifications of the first embodiment are similar to and have the same effects as the effects of the endoscope1. Thus, in the following description, the components having the same functions as the functions of the components of the endoscope1are assigned the same reference signs and the descriptions will be omitted.

Modification 1 of First Embodiment

In the distal end cover30of the endoscope1, the width W31of the annular first area31is substantially the same throughout the entire circumference. While on the other hand, as shown inFIG.5andFIG.6, in the distal end cover30of the endoscope1A of the present modification, a width W31B (first width) of the first area31where a distance L31from the air/water feeding nozzle19to an outer periphery of the first area31is longest is greater than a width W31A (second width) of the first area31where the distance from the air/water feeding nozzle19to the outer periphery of the first area31is shortest.

Note that as shown inFIG.6, for example, the width W31of the first area31is the length of the first area31in the direction along the shortest line connecting the center C15of the observation window15and the first area31. The distance L31is a length between the center of the width W31in the direction along the shortest line and the center of the opening C19of the air/water feeding nozzle19. Hereinafter, the “center of the opening C19” is referred to as the “opening C19.”

Note that in a distal end cover30A, the width W31of the first area31gradually increases as the distance L31from the air/water feeding nozzle19becomes longer (FIG.7, A).

The outer circumference (inner circumference of the first area31) of the observation window15, the outer circumference (inner circumference of the second area32) of the first area31, and the outer circumference (inner circumference of the third area33) of the second area32are all circular. A center C31of the first area31and a center C32of the second area32are at the same position on a center line CL, but are positioned farther from the air/water feeding nozzle19as compared to the center C15of the observation window15.

In the endoscope1A, the water flowing over the outer surface15SA of the observation window15is more unlikely to remain in the lower portion of the step as compared to the endoscope1. Therefore, even in the endoscope having the optical system with a wide angle of view, water droplets are not seen on an image.

Note that as shown inFIG.7, in the endoscope1A, the width W31of the first area31gradually increases in a curve as the distance L31from the air/water feeding nozzle19becomes longer (A). While on the other hand, the width W31may linearly increase relative to the distance L31(B). Further, at least a portion of the width W31may increase relative to the distance L31(C, D).

For the efficient air/water feeding, the width W31B is preferably more than 1.2 times the width W31A.

Modification 2 of First Embodiment

As shown inFIG.8, in a distal end cover30B of the endoscope1B of the present modification, the width W32of the second area32also increases as a distance L32from the air/water feeding nozzle19becomes longer. Therefore, a width W32B (third width) of the second area32where the distance L32from the air/water feeding nozzle19to an outer periphery of the second area32is longest is greater than a width W32A (fourth width) of the second area32where the distance from the air/water feeding nozzle19to the outer periphery of the second area32is shortest. For the efficient air/water feeding, the width W32B is preferably more than three times, particularly, more than five times the width W32A.

The outer circumference of the first area31and the outer circumference of the second area32are both circular. The center C32of the second area32is positioned farther from the opening C19of the air/water feeding nozzle19as compared to the center C31of the first area31on the center line CL. Conversely, the center C15of the observation window15, the center C31of the first area31, and the center C32of the second area32are positioned on the same line (center line CL) and become closer to the opening C19of the air/water feeding nozzle19in the aforementioned order.

In the endoscope1B, the water flowing over the outer surface15SA of the observation window15is more unlikely to remain in the lower portion of the step as compared to the endoscope1A, when flowing down the second area32to the third area33. Therefore, even in the endoscope having the optical system with a wide angle of view, water droplets are not seen on an image.

Modification 3 of First Embodiment

In a distal end cover30C of the endoscope1C of the present modification shown inFIG.9, the outer circumference (inner circumference of the second area32) of the first area31and the outer circumference of the second area32are elliptic. The center C31of the first area31and the center C32of the second area32are positioned on the center line CL. Note that the center of the ellipse means a midpoint between two focal points. The center C32has a longer distance from the air/water feeding nozzle19than the center C31.

In the distal end cover30C, the width W31of the first area31more significantly changes as compared to the distal end cover30B depending on the distance from the air/water feeding nozzle19. Thus, in the endoscope1C, the water flowing over the outer surface15SA of the observation window15is more unlikely to remain in the lower portion of the step as compared to the endoscope1B. Therefore, even in the endoscope having the optical system with a wide angle of view, water droplets are not seen on an image.

Note that the shape of the first area31and the shape of the second area32may be substantially circular or substantially elliptic, instead of being in a perfect circle or an ellipse.

Modification 4 of First Embodiment

The distal end surface30SA of a distal end cover30D of the endoscope1D of the present modification shown inFIG.10includes an annular fourth area34(fourth surface) between the observation window15and the first area31. The outer circumference of the observation window15and an inner circumference of the fourth area34contact with each other and the inner circumference of the first area31and an outer circumference of the fourth area34contact with each other. The fourth area34is a plane parallel to the outer surface15SA of the observation window15and the third area33. The outside rounded corner area may be formed at a boundary between the first area31and the fourth area34. In the modifications1and2also, the fourth area34may be formed.

In the fourth area34of the distal end cover30D shown inFIG.10, a width W34is constant, but in the fourth area34, the width W34may vary.

Modification 5 of First Embodiment

In the distal end surface30SA of a distal end cover30E of the endoscope1E of the present modification shown inFIG.11, the fourth area34projects toward the air/water feeding nozzle19. Accordingly, a portion of the first area31and a portion of the second area32also project toward the air/water feeding nozzle19.

In the endoscope1E, the flow rates of the water and the air ejected from the air/water feeding nozzle19flowing toward the observation window15increase as compared to the endoscope1and the like. Accordingly, the endoscope1E has a further higher cleaning efficiency than the endoscope1and the like.

Modification 6 of First Embodiment

In the distal end surface30SA of a distal end cover30F of the endoscope1F of the present modification shown inFIG.12, the fourth area34projects toward the air/water feeding nozzle19and an outer edge facing the air/water feeding nozzle19is a straight line. Accordingly, the outer edges facing the air/water feeding nozzle19of the first area31and the second area32are also straight lines. In other words, regions facing the air/water feeding nozzle19of the first area31and the second area32are substantially rectangular. The portion of the first area31and the portion of the second area32are each equidistant from the air/water feeding nozzle19.

In the endoscope1F, the flow rates of the water and the air ejected from the air/water feeding nozzle19flowing toward the observation window15increase as compared to the endoscope1E. Accordingly, the endoscope1F has a further higher cleaning efficiency than the endoscope1E.

Second Embodiment

An endoscope1G of a modification of a second embodiment is similar to the endoscope1and the like. Therefore, hereinafter, the components having the same functions as the functions of the components of the endoscope1and the like will be assigned the same reference signs and the descriptions will be omitted.

As shown inFIG.13, in a distal end cover30G of the endoscope1G of the present embodiment, the width W31A of the first area31where the distance from the air/water feeding nozzle19is shortest is greater than the width W31B of the first area31where the distance L31from the air/water feeding nozzle19is longest. In the first area31and the second area32, as the distance from the air/water feeding nozzle19becomes longer, the width gradually decreases.

In the distal end cover30G, the center C31of the first area31and the center C32of the second area32are closer to the air/water feeding nozzle19as compared to the center C15of the observation window15.

As already described, after feeding water, the water is likely to remain around the opening of the air/water feeding nozzle19. However, the first area31with the width W31A has a smaller inclined angle than the first area31with the width W31B. Therefore, in the distal end cover30of the endoscope1, after feeding water, the water is unlikely to remain around the opening of the air/water feeding nozzle19. Thus, in the endoscope1, the air feeding is efficient.

Note that in the distal end cover30G of the endoscope1G, the width W32A of the second area32where the distance from the air/water feeding nozzle19is shortest is also greater than the width W32B of the second area32where the distance L32from the air/water feeding nozzle19is longest.

Third Embodiment

An endoscope1H of a third embodiment is similar to and has the same effects as the effects of the endoscope1and the like. Therefore, hereinafter, the components having the same functions as the functions of the components of the endoscope1and the like will be assigned the same reference signs and the descriptions will be omitted.

As shown inFIG.14, in a distal end cover30H of the endoscope1H, in the first area31, the width W31B of a region where the distance from the air/water feeding nozzle19is longest and the width W31A of a region where the distance from the air/water feeding nozzle19is shortest are both greater than a width W31X of a region between the region with the longest distance and the region with the shortest distance. In the second area32, the width W32B of a region where the distance from the air/water feeding nozzle19is longest and the width W32A of a region where the distance from the air/water feeding nozzle19is shortest are both greater than a width W32X of a region between the region with the longest distance and the region with the shortest distance.

In other words, in the distal end cover30H, in the first area31, the width of a region closer to the center line CL is wider than the width of a region farther from the center line CL. In the second area32, the width of a region closer to the center line CL is wider than the width of a region farther from the center line CL.

In the endoscope1H, after feeding water, the water is unlikely to remain around the opening of the air/water feeding nozzle19and the water flowing over the outer surface15SA of the observation window15is also unlikely to remain in the lower portion of the step. Therefore, the air feeding is efficient and even in the endoscope having the optical system with a wide angle of view, water droplets are not seen on an image.

Note that the outer edge of the first area31and the outer edge of the second area32of the distal end cover30H are substantially elliptic. However, the shape of the first area31and the second area32can be modified in various manners.

For example, in an endoscope1J of a modification of the third embodiment shown inFIG.15, the outer edge of the first area31and the outer edge of the second area32of a distal end cover30J are in such a shape as an athletics track field.

The endoscope1of the embodiment may be a flexible endoscope with the insertion portion6that is flexible or a rigid endoscope with the insertion portion6that is rigid. The endoscope1may be for either medical use or industrial use.

The present disclosure is not limited to the aforementioned embodiments and the like, and various changes, combinations, and applications are available within the scope without departing from the gist of the disclosure.