Optical unit

1. An optical unit comprising:

a reflection portion, configured to reflect an incident light flux incident from outside in a reflection direction from an incident direction to an imaging element on a reflection surface;

a movable body, configured to support the reflection portion;

a fixed body; and

a rotation support mechanism, configured to rotate the movable body with respect to the fixed body with an axial direction crossing the incident direction and the reflection direction as a rotation axis, wherein

the rotation support mechanism has: a spring member in a U-shape that is disposed between the fixed body and the movable body in the axial direction and applies a force in a widening direction to widen a space between the fixed body and the movable body in the axial direction;

the spring member has a rotation-axis first forming member that constitutes the rotation axis;

the movable body has a rotation-axis second forming member that constitutes the rotation axis together with the rotation-axis first forming member; and

the rotation-axis first forming member and the rotation-axis second forming member are disposed at positions where the rotation axis passes through a center of gravity position of the movable body.

2. The optical unit according to claim 1 , wherein

one of the rotation-axis first forming member and the rotation-axis second forming member has a convex spherical surface, and

the other of the rotation-axis first forming member and the rotation-axis second forming member has a concave spherical surface on which the convex spherical surface slides.

3. The optical unit according to claim 2 , wherein

the convex spherical surface is formed by fixing, to a base having a hole, a spherical body having a diameter larger than the hole.

4. The optical unit according to claim 1 , wherein

the spring member is fixed at a fixed position of the fixed body by being inserted in an insertion direction crossing the axial direction in the space and has a protruding portion that protrudes in a direction opposite to the insertion direction and is displaceable in a displacement direction crossing the insertion direction; and

the fixed body has a hooking portion on which the protruding portion is displaced in the displacement direction and hooked as the spring member is inserted into the fixed position.

5. The optical unit according to claim 1 , wherein

the movable body has a groove in an arc-shape with a center of rotation of the rotation axis as the center of rotation; and

the spring member has a convex portion that is inserted into the groove.

6. The optical unit according to claim 5 , wherein

the groove has such a length that the groove and the convex portion are not in contact with each other in an arc direction even when the movable body is rotated at the maximum as the movable body is rotated with respect to the fixed body.

7. The optical unit according to claim 1 , wherein

the spring member is fixed at a fixed position of the fixed body by being inserted in the insertion direction in the space, and

a contact position with the fixed body in the widening direction is a position aligned with the rotation axis.

8. The optical unit according to claim 1 , wherein

the fixed body has a depression or an opening formed on an extension line in a direction of movement accompanying a rotation of the movable body.