FOCAL-PLANE SHUTTER AND OPTICAL INSTRUMENT

摘要

A focal-plane shutter is provided with: a base plate having an aperture; an arm having a base end rotatably supported by the base plate, and a leading end that oscillates due to the base end rotating with respect to the base plate; a curtain that is connected to the arm so as to enable the aperture to open and close; and sensors which are disposed in a position facing the arm on opposite sides of the aperture, and which detect the state of the curtain. The curtain has first and second blades. The location where the second blade and the arm are connected is positioned nearer to the base end of the arm than the location where the first blade and the arm are connected. The second blade comprises: a base end connected to the arm; a middle section that enables the aperture to be closed; and a leading end that is capable of shielding at least part of the sensor, and which protrudes toward the first blade.