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US 5,962,961 AGranted
Thermal field emission electron gun
AssigneeJEOL Ltd. and JEOL Engineering Co., Ltd.
InventorsIwao Sakai, Tokuo Mizuno
Life of this patent
Estimating the term…
Abstract
There is disclosed a long-lived thermal field emission electron gun for use in a scanning electron microscope. The gun has a tungsten tip. The surface of this tip is coated with zirconium, zirconium oxide, titanium or titanium oxide. A wire member is mounted above the front end of the tungsten tip to prevent the coating of zirconium or other material from slipping off.
Claims8
A thermal field emission electron gun comprising:
- a tungsten needle-like tip having a tapered front end from which electrons are emitted;
- a solid coating formed on a surface of said tungsten needle-like tip, a solid coating member spaced from the tapered front end;
- said solid coating member supplying coating material to the tapered front end of the tungsten tip;
- and
- a slip preventive member mounted and spaced from the tapered front end of the tungsten tip for preventing said solid coating member from slipping off.
2 more elements
A thermal field emission electron gun comprising:
- a tungsten needle-like tip having a front tapered end from which electrons are emitted;
- a solid coating formed on a surface of said tungsten tip, a solid coating member spaced from the tapered front end said solid coating member supplying coating material to the tapered front end of the tungsten tip;
- and
- at least one groove formed and spaced from the tapered front end of the tungsten tip for preventing said solid coating member from slipping off.
1 more element
Dependencies are inferred from the claim text.