Patent ID: 7796351

Claim:
An optical axis tilting device for a laser optical system comprising: a lens barrel in which a laser optical system is disposed; a tilt frame with a Z axis coincident with an optical axis of the laser optical system and an X axis and a Y axis being orthogonal to each other in a plane orthogonal to the Z axis, and being tilted in at least one of an X-axis direction and a Y-axis direction and provided with a tilt sensor detecting a horizontal reference position; a tilt mechanism tilting the tilt frame relative to the lens barrel and comprising a drive motor, a threaded shaft rotated by the drive motor, a movable member reciprocated by the shaft and engaging with the tilt frame to tilt the tilt frame relative to the lens barrel, and a position detector detecting a position of the movable member relative to the lens barrel; a leveling mechanism supporting the lens barrel tiltably, and tilting the lens barrel to level the tilt frame so that the tilt sensor detects the horizontal reference position; a ball joint mechanism allowing the tilt frame to be supported by the lens barrel and comprising a ball support portion in the lens barrel, a ball portion made of a magnetic material and supported between the ball support portion and the tilt frame, a conical recess formed in a first one of the ball support portion and the tilt frame, with an inner circumferential wall of said conical recess being relatively and rotatably in contact with the ball portion, and a permanent magnet provided in said first one of the ball support portion and the tilt frame in which the conical recess is formed, to attract the ball portion into the inner circumferential wall; and a computing portion computing a tilt angle of the tilt frame relative to the lens barrel according to the position of the movable member detected by the position detector.