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US 4,643,548 AGranted
Shutter mechanism for a video tape camera
AssigneeNisus Video Incorporated
InventorSteven L. Swinehart
Life of this patent
Estimating the term…
Abstract
A focal plane shutter for a video camera has a pair of disks rotated in the same direction about a common axis in synchronism with the raster scan blanking interval. The disks each have one or more openings which overlie one another to define a light admitting shutter aperture positioned to illuminate the video pickup device. The opening in at least one of the disks is counterbalanced during rotation by a recessed relief area which does not extend through the disk, or by a weighted plate attached to the disk.
Claims46
A focal plane shutter for a video camera having a lense and pickup comprising:
- disk means positioned between said lense and said pickup for rotation about an axis to define an annular locus in registration with said pickup,
- said disk means having light admitting aperture means intersecting said locus,
- means for substantially balancing said disk means during rotation,
- said means for balancing comprising at least one recessed relief area means formed in said disk means and not extending entirely through said disk means, and
- means for rotating said disk means.
2 more elements
A focal plane shutter mechanism for a video camera having a light sensing pickup comprising:
- first disk means and second disk means disposed in said camera for rotation about an axis, each of said first and second disk means having light admitting aperture means,
- said first disk means having a recessed relief area means formed therein to counterbalance its light admitting aperture means, said relief area means extending only partially through said disk means, and
- said second disk means having means for counterbalancing its light admitting aperture means.
A focal plane shutter mechanism for a video camera having a lense and pickup, said mechanism comprising:
- disk means positioned between said lense and said pickup for rotation about an axis to define an annular locus in registration with said pickup;
- said disk means having a single light admitting aperture intersecting said locus;
- said disk means, except for said aperture, being opaque to the passage of light between said lense and said pickup;
- said disk means comprises first and second disk means rotatable about a common axis;
- means for rendering substantially zero the polar moment of inertia of said disk means;
- said means for rendering substantially zero the polar moment of inertia comprising at least one recessed relief area, said recessed relief area formed in said disk means and not extending entirely through said disk means;
- and
- means for rotating said disk means.
5 more elements
A shutter mechanism for a video camera of the type which scans a raster with periodic retraces, said video camera having a lense and pickup device forming a focal plane, said improvement comprising:
- a first disk positioned between said lense and said pickup device and having an axis of rotation offset from said focal plane;
- a second disk positioned adjacent said first disk and having a common axis of rotation with said first disk;
- said first disk having a single light admitting aperture intersecting said focal plane when said first disk is rotating;
- said second disk having a single light admitting aperture intersecting said focal plane when said second disk is rotating;
- first balancing means for substantially balancing said first disk means, said first balancing means comprising a recessed relief area not extending through said first disk means;
- second balancing means for substantially balancing said second disk means;
- said light admitting apertures of said first and second disk means being in registration to form an angular opening in said focal plane once per revolution of said first and second disk means;
- said first and second disk means except for said light admitting apertures not permitting the passage of light between said lense and said pickup device;
- means for adjusting the size of said angular opening;
- drive means for rotating said first and second disk means about said axis of rotation at nominally 3600 revolutions per minute;
- and
- means for synchronizing the rotation of said first and second disk means and the positioning of said angular opening in said focal plane with said periodic retraces.
9 more elements
A focal plane shutter mechanism for a video camera of the type which scans a raster with periodic retraces and has a light sensing pickup, said improvement comprising:
- disk means positioned on said camera and comprising first and second disk means rotatable about a common axis;
- each of said first and second disk means having a single light admitting aperture and balancing means;
- said balancing means comprising recessed relief area, said recessed relief areas formed in said disk means and not extending entirely through said disk means;
- and
- said disk means being disposed relative to said pickup at all times to block light from reaching said pickup, except during a single uninterrupted interval occurring not more than once each revolution of said disk means and lasting for less than the period of revolution;
- rotation means for rotating said disk means;
- and
- means for synchronizing the rotation of said disk means and the positioning of said light admitting apertures relative to said pickup and said periodic retraces.
5 more elements
A focal plane shutter for a video camera having a lense and pickup comprising:
- disk means positioned between said lense and said pickup for rotation about an axis to define an annular locus in registration with said pickup,
- said disk means having light admitting aperture means intersecting said locus, said light admitting aperture means positioned on said disk means such that two sides of said aperture means are bound by a pair of intersecting lines generating from a point offset a predetermined distance from the geometric center of said disk means,
- means for substantially balancing said disk means during rotation,
- said means for balancing comprising at least one weighted means attached to said disk means, and
- means for rotating said disk means.
2 more elements
A focal plane shutter mechanism for a video camera having a light sensing pickup comprising:
- first disk means and second disk means disposed in said camera for rotation about an axis, each of said first and second disk means having light admitting aperture means, said light admitting aperture means positioned on said disk means such that two sides of said aperture means are bound by a pair of intersecting lines generating from a point offset a predetermined distance from the geometric center of said disk means,
- said first disk means having a weighted means secured thereto to counterbalance its light admitting aperture means, said weighted means being positioned adjacent said light admitting aperture means, and
- said second disk means having means for counterbalancing its light admitting aperture means.
A focal plane shutter mechanism for a video camera having a lense and pickup, said mechanism comprising:
- disk means positioned between said lense and said pickup for rotation about an axis to define an annular locus in registration with said pickup;
- said disk means having a single light admitting aperture intersecting said locus, said light admitting aperture means positioned on said disk means such that two sides of said aperture means are bound by a pair of intersecting lines generating from a point offset a predetermined distance from the geometric center of said disk means,
- said disk means, except for said aperture, being opaque to the passage of light between said lense and said pickup;
- said disk means comprises first and second disk means rotatable about a common axis;
- means for rendering substantially zero the polar moment of inertia of said disk means;
- said means for rendering substantially zero the polar moment of inertia comprising at least one weighted means, and
- means for rotating said disk means.
4 more elements
Dependencies are inferred from the claim text.