Light shield mechanism for quadrilateral opening
AssigneeAsahi Kogaku Kabushiki Kaisha
InventorTetsuji Shono
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Abstract
A rotatable member overlying a relatively fixed member has a quadrilateral window corresponding to a similar quadrilateral window within the fixed member through which passes the pivot axis of the rotating member. The rotating member controls movement of a pair of shield blades movable towards and away from each other from opposite sides of the window within the fixed member such that light shielding of the optical path through the fixed member window is effected partially by overlapping of the window frame portion of the rotating member relative to the window frame portion of the fixed member and the remaining portion of the fixed window is covered by the shield blades.
Claims4
A light shield mechanism for selectively closing off a light path through a first window within a relatively fixed member, said mechanism comprising:
- a rotatable member mounted coplanar to said first member for rotation about an axis passing through said first window and having an opening therein forming a second window, and
- shield blades mounted for rotation on said fixed member to respective sides of said windows and responsive to relative rotation of said fixed and rotatable members to rotate towards each other to selectively close off said first window with said first and second windows being of such size, location and configuration that rotation of said rotatable member relative to said fixed member causes said rotatable member to partially overlap a portion of said first window with the remainder of said first window being covered by said blades.
Dependencies are inferred from the claim text.