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US 5,757,118 AGranted
X-ray image intensifier tube apparatus having magnetic shield
AssigneeKabushiki Kaisha Toshiba
InventorHiroshi Kubo
Life of this patent
Estimating the term…
Abstract
In an X-ray image intensifier tube apparatus inc-luding a cylindrical magnetic shield placed to surround the outer periphery of an X-ray image intensifier tube, a ferromagnetic thin plate is placed in front of a convex input window of a vacuum envelope and a correcting magnetic coil is placed inside the cylindrical magnetic shield to surround the input window. This structure allows an output image which is substantially free of distortion to be obtained.
Claims7
An X-ray image intensifier tube apparatus comprising:
- an X-ray image intensifier tube equipped with a vacuum envelope having at its one end an X-ray input window with a convex surface;
- an input screen, having a convex surface, for converting an X-ray image received through said X-ray input window into a photo-electric image;
- an arrangement of electrodes for accelerating and focusing electrons forming said electronic image;
- and an output screen for converting said electronic image into an optical or electrical output image;
- a cylindrical magnetic shield placed to surround said X-ray image intensifier tube and made of a ferromagnetic material;
- a thin and substantially flat plate placed in front of said input window of said tube, made of a ferromagnetic material the same as or similar to that of the cylindrical magnetic shield and having a thickness within a range of 30 to 150 micrometers which corresponds to that of 1.5 to 20% of the thickness of said cylindrical magnetic shield;
- and
- an electromagnetic coil magnetically coupled with said cylindrical magnetic shield and placed in a region inside one end of said cylindrical magnetic shield on the side of said input window to surround the principal portion of said input window of said tube.
5 more elements
An X-ray image intensifier tube apparatus comprising:
- an X-ray image intensifier tube equipped with an X-ray image input window forming part of a vacuum envelope and having an convex surface;
- an input screen formed on the inner surface of said input window for converting an incident X-ray image into a photoelectric image;
- an arrangement of electrodes for accelerating and focusing electrons forming said electronic image;
- and an output screen for converting said electronic image into an optical or electrical output image;
- a cylindrical magnetic shield placed to surround said X-ray image intensifier tube;
- a ferromagnetic thin and substantially flat plate placed in front of said input window of said tube, said ferromagnetic thin plate and said cylindrical magnetic shield being made of the same ferromagnetic material or similar ferromagnetic materials, the thickness of said ferromagnetic thin plate being within a range of 1.5 to 20% of the thickness of said cylindrical magnetic shield;
- and
- an electromagnetic coil magnetically coupled with said cylindrical magnetic shield and placed in a region inside one end of said cylindrical magnetic shield on the side of said input window to surround the principal portion of said input window of said tube.
5 more elements
Dependencies are inferred from the claim text.