An object of the invention is to provide an endoscope capable of continuously grasping a direction which a distal end portion of an endoscope faces even when a bending operation is performed. The endoscope of the invention is provided with: a first image pickup optical system provided at a distal end of an insertion portion; a bending portion provided in a vicinity of a distal end portion of the insertion portion and configured to be bendingly operated by a proximal side operation; and a second image pickup optical system disposed on the bending portion and configured so that the distal end of the insertion portion is included within a field-of-view angle.

An operation switching mechanism includes a wire, a reciprocating movement member, a first biasing member, a second biasing member, switching members configured to switch states in which the first biasing member and the second biasing member perform biasing, and an operation member configured to operate the switching members according to operation from an outside and move the reciprocating movement member to a first movement position or a second movement position.

One or more devices, systems, methods, and storage mediums for detecting and guiding optical connection(s) using one or more imaging modalities are provided herein. Examples of applications include imaging, evaluating and diagnosing biological objects, such as, but not limited to, for Gastro-intestinal, cardio and/or ophthalmic applications, and being obtained via one or more optical instruments, such as, but not limited to, optical probes, catheters, capsules and needles (e.g., a biopsy needle). Devices, systems, methods, and storage mediums may include or involve a method, such as, but not limited to, for guiding and/or determining status of engagement and/or disengagement of one or more optical connections. A device, system, method, or storage medium may detect, monitor, and/or guide a probe/catheter to minimize, reduce, and/or avoid engagement and disengagement failures and to have a robust means of determining status of probe/catheter engagement to an apparatus or system.

An endoscope includes a prism disposed in a distal end portion of an insertion section and configured to change a direction of a field of view in an upward, downward, leftward, or rightward direction, an operation lever disposed in an operation section, being turnable from a neutral position around a third axis and a fourth axis that are perpendicular to each other, and including a second longitudinal axis, a cylindrical member disposed such that turning around a fourth axis of the lever is transmitted and configured to turn around the fourth axis by inclining the operation lever, a transmission wire configured to transmit turning around a first axis to the prism in response to an inclination operation around the third axis of the lever, and gears configured to transmit turning around a second axis to the prism in response to a turning operation around the fourth axis.

An objective optical system for endoscope includes, a first group having a positive refractive power, an aperture stop, and a second group having a positive refractive power, wherein the first group includes a first lens having a negative refractive power, and a second lens having a positive refractive power, the second group includes a cemented lens, and the cemented lens includes a third lens having a positive refractive power and a fourth lens having a negative refractive power, and the following conditional expressions (1), (2), (3), (4), (7) and (9) are satisfied:

0.13≦La/Lb≦0.17   (1),

−2.7≦f4/f≦−2.2   (2),

−0.7≦(ne2×f2)/(ne4×f4)≦0   (3),

2.5≦νd3/νd4≦3.5   (4)

−2.6≦r2o/rcc≦−2   (7), and

−1.2≦r2i/f2≦−0.9   (9).

An endoscope achieves favorable advancing and retracting motion without causing disturbance in displacement of built-in components in bending of a bending tube by covering, out of an image pickup cable and a conduit that are cross-symmetrical built-in components disposed to intersect with each other in a radial direction of the bending tube, an outer circumference of the conduit with a second heat-shrinkable tube serving as a protective member, and removing the second heat-shrinkable tube from a partial region that includes a region (an intersection region) where the image pickup cable and the conduit intersect with each other, even when the built-in components in the bending tube are intersected with each other.

There is provided an endoscope objective optical system with a small size and a high image quality, and in which, an adequate space for disposing a visual-field direction converting element is secured. The endoscope objective optical system, comprising in order from an object side: a first group having a negative refractive power; an aperture stop; and a second group having a positive refractive power, wherein the first group includes in order from the object side, a first lens having a negative refractive power and a visual-field direction converting member, and the second group includes in order from the object side, a second lens having a biconvex shape and a cemented lens in which a third lens having a positive refractive power and a fourth lens having a negative refractive power are cemented in this order, and the endoscope objective optical system satisfies the following conditional expressions (1), (2), (3), and (4)

2.4≦d.sub.1/f≦4.6   (1)

1.85≦f.sub.2/f≦2.6   (2)

−50≦r.sub.21/r.sub.22≦−0.4   (3)

2.01≦≦f.sub.03/f≦2.5   (4) where, d.sub.1 denotes an air conversion length from a surface on an image side of the first lens up to a surface of the aperture stop, f denotes a focal length of the overall endoscope objective optical system, f.sub.2 denotes a focal length of the second group, r.sub.21 denotes a radius of curvature of a surface on the object side of the second lens, r.sub.22 denotes a radius of curvature of a surface on the image side of the second lens, and f.sub.03 denotes a focal length of the third lens.

There is provided an endoscope objective optical system having a thin diameter, a wide in-water angle of view, a small variation in the angle of view, and a short overall length of the optical system.

The endoscope objective optical system includes in order from an object side, a front group GF having a negative refractive power, an aperture stop, and a rear group GR having a positive refractive power, wherein the front group includes a first negative lens L1 and a second negative lens L2, and the following conditional expressions (1), (2), (3′), and (4) are satisfied:

1<Iw/ft<1.8  (1),

4<Lt/Iw<9.5  (2),

1.49≦Lsf/ft≦2.30  (3′), and

0.38<ΣLa/Lsf<0.6  (4).

There is provided an objective optical system for endoscope which is small-sized, and has a favorable optical performance and fast F-number.

An objective optical system for endoscope comprises in order from an object side: a first lens having a negative refractive power; a second meniscus lens having a positive refractive power with a convex surface thereof directed toward the object side; an aperture stop; a third lens having a biconvex shape, and a cemented lens having a positive refractive power as a whole, in which a fourth lens having a biconvex shape and a fifth lens having a negative refractive power are cemented, wherein the objective optical system for endoscope satisfies the following conditional expressions (1), (2), and (9).

−3≦f.sub.1/Ih≦−1.2  (1)

0.25≦L.sub.3.sub._.sub.5/L≦0.7  (2)

0.2≦r.sub.2/r.sub.3≦0.8  (9) where, f.sub.1 denotes a focal length of the first lens; Ih denotes the maximum image height of the objective optical system for endoscope; L.sub.3.sub._.sub.5 denotes a distance along an optical axis from a surface on the object side of the third lens up to a surface on an image side of the fifth lens, L denotes a distance along the optical axis from a surface on the object side of the first lens up to an image plane, r.sub.2 denotes a radius of curvature of a surface on an image side of the first lens, and r.sub.3 denotes a radius of curvature of a surface on the object side of the second meniscus lens.

An endoscope is provided with an endoscope shaft and a main body connected to the endoscope shaft. The endoscope includes a camera connection to which an optical recording device can be mechanically fixed. The main body is electrically conductive. The camera connection includes an electric insulating body that electrically insulates an optical recording device, mechanically fixed to the camera connection, from the main body.