Source: {"pile_set_name": "USPTO Backgrounds"}

1. Field of the Invention
The present invention relates to a technology of a mirror drive apparatus including a movable unit with a mirror provided therein and used to switch an optical path.
2. Description of the Related Art
A single-lens reflex camera (imaging apparatus) typically includes a mirror box (mirror drive apparatus) configured as what is called a quick-return mirror insertable and retractable to and from the optical path of an imaging lens. The mirror box includes a mirror unit (movable unit) that can change its position (attitude) between an inserted position in which the mirror unit is inserted to the optical path and a retracted position in which the mirror unit is retracted from the optical path.
An example of the mirror box includes a locking mechanism that works against a mirror drive spring to lock the mirror unit in the inserted position and a drive mechanism that releases the mirror unit locked by the locking mechanism so that the mirror drive spring drives the mirror unit to the retracted position (see JP-UM-B-57-16179, for example).