Adjusting mechanism

An adjusting mechanism comprising:

• a movable plate having a substantially rectangular shape and including a long side and a short side;
• a position adjusting actuator configured to come into contact with and press the movable plate;
• a reference plate on which the movable plate is placed;
• and
• an elastic member coupling the movable plate and the reference plate, the elastic member being elastically deformable, wherein:
• in a plane of the movable plate, a coordinate axis parallel to the long side of the movable plate is a Y axis, a coordinate axis orthogonal to the Y axis is an X axis, a coordinate axis orthogonal to the plane of the movable plate is a Z axis, and a rotating direction around the Z axis is a θz direction,
• the elastic member is elastically deformable in a direction along the X axis, and
• the position adjusting actuator adjusts a position of the movable plate with respect to the reference plate when the position adjusting actuator presses the movable plate in the direction along the X axis and moves the movable plate in the direction along the X axis and the θz direction.