OBLIQUE TIP ENDOSCOPE WITH ZERO DEGREE FIELD ANGLE

1 . (canceled)

2 . A method of assembling an endoscope, comprising:

obtaining an outer tube defining a first central axis, a first proximal end, and a first distal tip, and including a first portion at the first distal tip defining a first plane that forms an angle of between and including 20 and 40 degrees to the first central axis, and a second portion at the first distal tip defining a second plane perpendicular to the first central axis;

obtaining an inner tube defining a second central axis, a second proximal end, and a second distal tip, and including a first portion at the second distal tip defining a third plane that forms an angle of between and including 20 and 40 degrees to the second central axis and a second portion at the second distal tip defining a fourth plane perpendicular to the second central axis;

inserting the inner tube into the outer tube until the first and third planes are coplanar and two channels are defined within the outer tube, the first channel defined within the inner tube and the second channel defined between the inner tube and an inner surface of the outer tube;

inserting a visualization conduit into the second channel; and

optically exposing the visualization conduit at the first distal end to define a viewing angle parallel to the first central axis.

3 . The method of claim 2 , wherein the first plane forms an angle between and including 30 and 34 degrees.

4 . The method of claim 3 , wherein the first plane forms an angle of about 32 degrees.

5 . The method of claim 2 , further comprising:

attaching the inner tube to the outer tube at the first distal and second distal tips; and

attaching the inner tube to the outer tube at the first and second proximal ends.

6 . The method of claim 5 , wherein at least one of the attaching steps includes soldering.

7 . The method of claim 2 , further comprising:

inserting a light fiber bundle into the second channel with the visualization conduit; and

optically exposing the light fiber bundle at the second plane.

8 . The method of claim 2 , wherein the outer tube further includes:

a first dimension measured perpendicularly to the first central axis and a second dimension measured perpendicularly to the first central axis and at a right angle to the first dimension, the second dimension equal to or smaller than the first dimension;

a first transition area on a first side of the first distal tip between the first portion and the second portion of the outer tube, the first transition area varying between the first portion and the second portion of the outer tube; and

a second transition area on a second side of the first distal tip opposite the first side, the second transition area varying between the first portion and the second portion of the outer tube.

9 . The method of claim 8 , wherein, with respect to the outer tube:

the first transition area defines a radius of curvature between and including 8% and 20% of the first dimension; and

the second transition area defines a radius of curvature between and including 8% and 20% of the first dimension.

10 . The method of claim 2 , wherein the inner tube further includes:

a third dimension measured perpendicularly to the second central axis, and a fourth dimension measured perpendicularly to the second central axis and at a right angle to the third dimension, the fourth dimension equal to or smaller than the third dimension;

a third transition area on a third side of the second distal tip between the first portion and the second portion of the inner tube, the third transition area varying between the first portion and the second portion of the inner tube; and

a fourth transition area on a second side of the second distal tip opposite the first side, the second transition area varying between the first portion and the second portion of the inner tube.

11 . the method according to claim 10 , wherein, with respect to the inner tube:

the third transition area defines a radius of curvature between and including 8% and 20% of the third dimension; and

the fourth transition area defines a radius of curvature between and including 8% and 20% of the fourth dimension.

12 . The method of claim 2 ,

wherein the outer tube further includes:

a first dimension measured perpendicularly to the first central axis and a second dimension measured perpendicularly to the first central axis and at a right angle to the first dimension, the second dimension equal to or smaller than the first dimension;

a first transition area on a first side of the first distal tip between the first portion and the second portion of the outer tube, the first transition area varying between the first portion and the second portion of the outer tube; and

a second transition area on a second side of the first distal tip opposite the first side, the second transition area varying between the first portion and the second portion of the outer tube,

and wherein the inner tube further includes:

a third dimension measured perpendicularly to the second central axis, and a fourth dimension measured perpendicularly to the second central axis and at a right angle to the third dimension, the fourth dimension equal to or smaller than the third dimension;

a third transition area on a third side of the second distal tip between the first portion and the second portion of the inner tube, the third transition area varying between the first portion and the second portion of the inner tube; and

a fourth transition area on a second side of the second distal tip opposite the first side, the second transition area varying between the first portion and the second portion of the inner tube.

13 . The method of claim 12 ,

wherein, with respect to the outer tube:

the first transition area defines a radius of curvature between and including 8% and 20% of the first dimension; and

the second transition area defines a radius of curvature between and including 8% and 20% of the first dimension; and

wherein, with respect to the inner tube:

the third transition area defines a radius of curvature between and including 8% and 20% of the third dimension; and

the fourth transition area defines a radius of curvature between and including 8% and 20% of the fourth dimension.

14 . The method of claim 13 , wherein the inner tube further includes:

a cross-sectional shape perpendicular to the second central axis, the cross-sectional shape defines a straight portion and a curved portion coupled on each end to the straight portion; and

a first height measured from an apex of the curved portion to the straight portion,

wherein the first height is greater half the first dimension of the outer tube, but smaller than an internal dimension of the outer tube measured parallel to the first dimension.

15 . The method of claim 2 , wherein the outer tube is formed from a metallic material.

16 . The method of claim 2 , wherein the inner tube is formed from a metallic material.