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Patent Number: |
6686680 |
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Case ID: |
83362 |
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Patent Title:
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Method and apparatus for regulating electron emission in field emitter devices |
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Status: |
ACTIVE |
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Status Date: |
2/3/2004 3:35:33 PM |
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Issue Date:
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2/3/2004 |
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Filed Date:
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1/13/2003 |
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Serial #:
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340669 |
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Assignee Name:
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The United States of America as represented by the Secretary of the Navy (Washington, DC) |
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Inventor(s):
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Shaw, Jonathan L. ,Hsu, David S. Y. |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to electron emission devices. More
particularly, it relates to a method and apparatus for improving the
performance of field emitter devices by detecting the emission of
electrons at excessively positive potentials and regulating the current
produced at the excessively positive potentials.
2. Description of Related Art
Field emission is a tunneling process where electrons move from a solid,
through a thin potential barrier, into vacuum without changing energy. The
field emitted current increases as a function of the electric field at the
emitter surface. A macroscopic field emitter tip requires a voltage
typically greater than 100V and often more than 1000V to cause emission.
The electronic, chemical, and geometric properties of the emitter surface
also have a substantial effect on the field emission current. The . . . . More |
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An apparatus and method for regulating the emission current from a single
(macroscopic) field emitter, from groups of emitters within a large
(microscopic) array, or from each cell within an array is described. The
apparatus includes an additional aperture, fabricated at each field
emitter array cell, to create and electron energy filter. The filter
aperture of the electron energy filter is similar to the gate aperture but
located above or in front of the gate aperture, and is held at a positive
potential lower than the gate. The filter allows only those electrons with
energy greater than some minimum (the cutoff energy) to pass through. A
current-limiting circuit is placed in series with the gate aperture,
limiting the total current of electrons that do not pass through the
filter. Thus, emission from low energy states is limited without limiting
emission from states near the Fermi level.
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What is claimed is:
1. A cathode apparatus capable of regulating current, comprising:
a first electrode, with at least one aperture therein, arranged on a
substrate;
an emitter structure formed on the substrate for injecting current when a
voltage supply is connected between the first electrode and the substrate;
a second electrode arranged above or adjacent to the first electrode,
wherein electrons failing to pass through the second electrode are
collected by said first electrode; and
a feedback circuit connected to said first electrode for reducing the
voltage applied to said first electrode in response to the electrons
collected by said first electrode.
2. The apparatus as in claim 1, wherein said second electrode includes at
least one aperture therein.
3. The apparatus as in claim 1, wherein potentials applied to the second
electrode are controlled so as to prevent electrons having energ . . . . More |
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