Endoscope optical system and image pickup apparatus

An endoscope optical system comprising:

• an objective optical system for forming an object image, said objective optical system including a prism member having at least a reflecting surface for bending an optical path;
• and
• an image transfer system for leading the object image formed by said objective optical system to an observation apparatus along a direction of a major axis;
• wherein said reflecting surface of said prism member has a surface configuration that produces decentration aberration;
• and
• wherein at least one of said reflecting surface and another reflecting surface of said prism member is a has no axis of rotational symmetry intersecting a surface of an area thereof where light is transmitted or reflected, said curved surface correcting said decentration aberration.

An image pickup apparatus, comprising:

• an image-forming optical system which forms an object image;
• an image pickup device which receives the object image formed by said image-forming optical system;
• and
• a monitor which converts the image received by said image pickup device into an electric signal and displays an image from the electric signal;
• wherein said image-forming optical system has a prism optical system in which at least one surface which transmits and/or reflects light from an object is formed from a curved surface,
• wherein said curved surface of said prism optical system is a non-rotationally symmetric surface,
• wherein said prism optical system has a prism formed from at least two curved surfaces,
• wherein said at least two curved surfaces include a first reflecting surface disposed at a tilt to face an object point, and a second reflecting surface tilted with respect to both said first reflecting surface and an image plane, at least one of said first and second reflecting surfaces being a non-rotationally symmetric surface having no axis of rotational symmetry, and
• wherein said prism optical system is arranged such that light rays from the object point travel along an optical axis and are reflected by said reflecting surface of said prism optical system toward a side opposite to the image plane with respect to the optical axis and then reflected by said second reflecting surface to reach the image plane by substantially intersecting said optical axis.

An image pickup apparatus, comprising:

• an image-forming optical system which forms an object image;
• an image pickup device which receives the object image formed by said image-forming optical system;
• and
• a monitor which converts the image received by said image pickup device into an electric signal and displays an image from the electric signal;
• wherein said image-forming optical system has a prism optical system in which at least one surface which transmits and/or reflects light from an object is formed from a curved surface,
• wherein said curved surface of said prism optical system is a non-rotationally symmetric surface,
• wherein said prism optical system has a prism formed from at least two curved surfaces,
• wherein said at least two curved surfaces include a first reflecting surface disposed at a tilt to face an object point, and a second reflecting surface tilted with respect to both said first reflecting surface and an image plane, at least one of said first and second reflecting surfaces being a non-rotationally symmetric surface having no axis of rotational symmetry;
• and
• wherein said prism optical system is arranged such that light rays from the object point travel along an optical axis and are reflected by said first reflecting surface of said prism optical system toward the image plane with respect to the optical axis and then reflected by said second reflecting surface to reach the image plane without intersecting said optical axis.