Image pickup apparatus for endoscope

An endoscope comprising:

• an insertion portion including a distal end portion, a bending portion and a flexible tube portion continuously provided in this order from a distal end side;
• and
• an image pickup apparatus including an image pickup optical portion and a moving mechanism portion arranged in the distal end portion,
• wherein the image pickup optical portion includes:
• an image pickup device unit including an image pickup device, and
• a lens unit including a moving lens that moves to a first observation position and a second observation position, the lens unit being included in an objective optical system that forms an optical image on an image pickup surface of the image pickup device, and
• wherein the moving mechanism portion is an actuator apparatus and includes,
• a first moving mechanism portion including a first elastic member having an urging force that comes into contact with a distal end surface of a moving frame projection portion of a moving lens frame in which the moving lens in the lens unit is disposed to make the moving lens frame be arranged at the first observation position, and
• a second moving mechanism portion including a second elastic member having an urging force larger than the urging force of the first elastic member, the urging force making the moving lens frame be arranged at the second observation position, and a shape memory alloy wire having a property of extending/contracting as a result of a temperature thereof changing due to a current applied from an external power supply via an electric cable, the shape memory alloy wire holding the second elastic member in a tensionless state when the shape memory alloy wire is extended, and contracting the second elastic member into a predetermined state and holding the second elastic member when the shape memory alloy wire is contracted, the shape memory alloy wire having a distal end portion and a proximal end portion arranged in the flexible tube portion of the insertion portion, the distal end portion being positioned on the bending portion side in the flexible tube portion;
• wherein the second moving mechanism portion further includes a driving force transmitting wire having a distal end portion fixed to a contact member arranged in a recess portion provided to the moving frame projection portion of the moving lens frame, and a proximal end portion that is fixed to a distal end portion of the shape memory alloy wire in the flexible tube portion of the insertion portion;
• and
• wherein the driving force transmitting wire is pulled with contraction of the shape memory alloy wire to cause the contact member fixed to the distal end portion of the driving force transmitting wire to move against the urging force of the second elastic member and cancel the urging force from the second elastic member to the moving frame projection portion.