Endoscope

An endoscope comprising:

• an elongated insertion section including a distal end portion, a proximal end portion, and a bendable portion located between the distal and proximal end portions;
• a fluid-pressure actuator for bending the bendable portion, said fluid-pressure actuator including:
• (a) an extensible body defining an internal space and having an extension axis along which the extensible body extends or contracts;
• and (b) expansion-restricting means for restricting expansion of the extensible body, said expansion-restricting mean causing the extensible body to extend in the direction of the extension axis when a fluid is supplied into the internal space, and causing the extensible body to contract in the direction of the extensible axis when the fluid is discharged from the internal space, said fluid-pressure actuator being arranged in the bendable portion of the insertion section and in parallel to a longitudinal axis of the insertion section, said fluid-pressure actuator having a first end coupled to a tip end of the insertion section and a second end coupled to a rear end of the bendable portion, said fluid-pressure actuator converting the extension or contraction of the fluid-pressure actuator into a bending motion of the bendable portion;
• and
• fluid supply/discharge means for supplying the fluid into the internal space of the extensible body or discharging the fluid from the internal space.

An endoscope comprising:

• an insertion section including a distal end portion and a proximal end portion;
• an optical system arranged in the insertion section and including an operatable portion;
• a fluid-pressure actuator for driving the operatable portion of the optical system, said fluid-pressure actuator including:
• (a) an extensible body defining an internal space and having an extension axis along which the extensible body extends or contracts;
• and (b) expansion-restricting means for restricting expansion of the extensible body, said expansion-restricting means causing the extensible body to extend in the direction of the extension axis when a fluid is supplied into the internal space, and causing the extensible body to contract in the direction of the extensible axis when the fluid is discharged from the internal space;
• conversion means for converting the extension or contraction of the fluid-pressure actuator into a motion of the operatable portion of the optical system;
• and
• fluid supply/discharge means for supplying the fluid into the internal space of the extensible body or discharging the fluid from the internal space.

An endoscope comprising:

• an elongated insertion section including a distal end portion, a proximal end portion, a bendable portion located between the distal and proximal end portions, and a base portion located between the bendable portion and the proximal end portion, said bendable portion and said base portion being detachably coupled to each other;
• fluid-pressure actuator means, at least part of which is arranged inside the base portion, for bending the bendable portion, said fluid-pressure actuator means defining an internal space therein, said fluid-pressure actuator means axially extending when a fluid is supplied into the internal space, and axially contracting when the fluid is discharged from the internal space, said fluid-pressure actuator means having a first end which is fixed to a proximal end of the bendable portion, and a second end which is located inside the base portion and serves as a free end;
• conversion means for converting the axial extension or contraction of the fluid-pressure actuator means to a bending motion of the bendable portion;
• and
• fluid supply/discharge means for supplying the fluid into the internal space of the fluid-pressure actuator means or discharging the fluid from the internal space.