Laminar flow electron gun and method

Claim 2

A particle gun for providing a beam of charged particles comprising a source of particles, an apertured dish-shaped control electrode surrounding said source and providing substantially a continuation thereof, an electrode spaced along the axis from said source and being at a potential with respect to the source and control electrode which will accelerate particles from the source, said electrode being shapEd to cooperate with the control electrode and source to provide a substantially uniform electric field at the source surface for initially accelerating the charged particles to substantially the same velocity to provide a substantially perpendicular uniform laminar flow of particles at the source surface and also providing an electric field spaced from the source along the path of the beam defining an electrostatic lens and at least an additional electrode along the path of the beam at a higher potential than said electrode for further accelerating the particle beam leaving said first electrode and focusing it on a target.

Claim 3

A particle gun as in claim 1 wherein said source is a cathode for providing electrons.

Claim 4

A particle gun as in claim 1 wherein said electrode spaced along the axis from said source includes an aperture for passing the beam, the diameter of said aperture being substantially larger than the diameter of the beam.

Claim 5

A particle gun as in claim 1 wherein means providing a magnetic focusing field cooperates with said additional electrode means.

Claim 6

A particle gun as in claim 1 wherein the angle of the surface of said dish-shaped electrode with respect to a plane perpendicular to the axis of the gun is between 0* and 45* .

Claim 7

An electron gun for providing an electron beam comprising a cathode having a surface providing a source of electrons, an apertured control electrode surrounding said cathode and having a surface providing substantially a continuation of the cathode surface, an anode spaced from said cathode surface and control electrode and being at a more positive potential than said cathode and control electrode to cooperate therewith to accelerate electrons at said surface to substantially the same velocity to provide a substantially uniform laminar flow of electrons in a beam substantially perpendicular at said cathode surface and toward said anode, said anode providing a diverging field along the path of the beam, and additional electrode means at a more positive potential for receiving and accelerating said beam and also serving to focus said beam.

Claim 8

An electron gun for providing an electron beam comprising a cathode having a surface providing a source of electrons, an apertured control electrode surrounding said cathode and having a surface providing substantially a continuation of the cathode surface, an anode spaced from said cathode surface and control electrode and being at a more positive potential than said cathode and control electrode to cooperate therewith to accelerate electrons at said surface to substantially the same velocity to provide a substantially uniform laminar flow of electrons in a beam substantially perpendicular at said cathode surface and toward said anode, said anode providing a diverging field along the path of the beam, and additional electrode means at a more positive potential for receiving and accelerating said beam and also serving to focus said beam.

Claim 9

An electron gun as in claim 6 wherein said anode means includes an cylindrical portion with an apertured-shaped end facing said cathode and control electrode.

Claim 10

An electron gun as in claim 7 wherein the diameter of said anode aperture is substantially larger than the diameter of the beam.

Claim 11

An electron gun as in claim 6 wherein the surface of said apertured control electrode defines an angle with a plane perpendicular to the axis of the tube which angle is between 0* and 45* .

Claim 12

An electron gun as in claim 7 wherein said additional electrode means comprises a cylindrical electrode for accelerating said beam and means providing final acceleration to said beam, said cylindrical electrode and said means providing final acceleration forming a focusing field.

Claim 13

An electron gun as in claim 10 wherein said last named means also provides a field-free region along the path of said beam after it leaves the cylindrical electrode.

Claim 14

An electron gun as in claim 10 wherein said cylindrical anode and cylindrical electrode are circular cylinders.

Claim 15

An electron gun as in claim 6 including means providing a magnetic focusing field cooperating with said additional electrode means.

Claim 16

A cathode ray tube having an envelope adapted to accommodate an electron gun at one end and having a screen at the other end including an electron gun comprising a cathode having a surface providing a source of electrons, an apertured control electrode surrounding said cathode surface and having a surface providing substantially a continuation of the cathode surface, an anode spaced from said cathode surface and control electrode having a surface portion facing and cooperating with said cathode surface and control electrode surface, said anode being at a more positive potential than said cathode and control electrode, said anode surface being shaped to provide a subStantially uniform electric field at said cathode surface to cause a laminar flow of electrons in a beam substantially perpendicular to said cathode surface at substantially the same velocity toward said anode, and additional means for receiving and acting on said beam after it leaves the anode to focus said beam.

Claim 17

A cathode ray tube having an envelope adapted to accommodate an electron gun at one end and having a screen at the other end including an electron gun comprising a cathode having a surface providing a source of electrons, an apertured control electrode surrounding said cathode surface and having a surface providing substantially a continuation of the cathode surface, an anode spaced from said cathode surface and control electrode having a surface portion facing and cooperating with said cathode surface and control electrode surface, said anode being at a more positive potential than said cathode and control electrode, said anode surface being shaped to provide a subStantially uniform electric field at said cathode surface to cause a laminar flow of electrons in a beam substantially perpendicular to said cathode surface at substantially the same velocity toward said anode, and additional means for receiving and acting on said beam after it leaves the anode to focus said beam.

Claim 18

A cathode ray tube as in claim 14 wherein said anode means includes a cylindrical portion with an apertured-shaped end facing said cathode and control electrode.

Claim 19

A cathode ray tube as in claim 15 wherein said additional electrode means comprises a cylindrical electrode further accelerating said beam and wherein the interior of the cathode ray tube envelope is conductive whereby to provide an additional electrode for giving the beam its final acceleration and cooperating with said electrode to focus the beam on the target.

Claim 20

An electron gun as in claim 14 wherein the surface of said apertured control electrode defines an angle with a plane perpendicular to the axis of the tube which angle is between 0* and 45* .

Claim 21

An electron gun as in claim 15 wherein the diameter of said anode aperture is substantially larger than the diameter of the beam.

Claim 26

An electron gun for providing an electron beam comprising a cathode having a surface providing a source of electrons, a control electrode adjacent said cathode surface and having a surface providing a continuation of the cathode surface, an anode spaced from said cathode surface and control electrode and cooperating therewith to cause electrons to emit substantially normal from said surface and provide a substantially uniform laminar flow of electrons in a beam from said cathode surface towards said anode, and additional electrode means for receiving and accelerating and focusing the beam.

Claim 27

An electron gun for providing an electron beam comprising a cathode having a surface providing a source of electrons, a control electrode adjacent said cathode surface and having a surface providing a continuation of the cathode surface, an anode spaced from said cathode surface and control electrode and cooperating therewith to cause electrons to emit substantially normal from said surface and provide a substantially uniform laminar flow of electrons in a beam from said cathode surface towards said anode, and additional electrode means for receiving and accelerating and focusing the beam.

Claim 28

An electron gun for providing an electron beam comprising a cathode having a surface providing a source of electrons, a control electrode adjacent said cathode surface and having a surface providing a continuation of the cathode surface, said control electrode being at a voltage substantially equal to or more negative than said cathode, an anode spaced from said cathode surface and control electrode, said anode including a surface portion facing said cathode and control electrode, said anode being at a potential which is positive with respect to said cathode and control electrode to cooperate therewith to cause electrons to emit substantially normal and at substantially the same velocity from said cathode surface and provide a sUbstantially uniform laminar flow of electrons in a beam from said cathode surface towards said anode, and additional electrode means at a potential position with respect to said anode for receiving and accelerating and focusing the beam.

Claim 29

An electron gun for providing an electron beam comprising a cathode having a surface providing a source of electrons, a control electrode adjacent said cathode surface and having a surface providing a continuation of the cathode surface, said control electrode being at a voltage substantially equal to or more negative than said cathode, an anode spaced from said cathode surface and control electrode, said anode including a surface portion facing said cathode and control electrode, said anode being at a potential which is positive with respect to said cathode and control electrode to cooperate therewith to cause electrons to emit substantially normal and at substantially the same velocity from said cathode surface and provide a sUbstantially uniform laminar flow of electrons in a beam from said cathode surface towards said anode, and additional electrode means at a potential position with respect to said anode for receiving and accelerating and focusing the beam.

Claim 30

An electron gun for projecting an electron beam comprising a cathode having a surface providing a source of electrons, a control electrode adjacent said cathode and having a surface providing a continuation of said cathode surface, said control electrode being at a potential equal to or more negative than said cathode, an anode spaced from said cathode surface and said control electrode including a surface portion which faces said cathode surface and control electrode surface, said anode being at a potential which is positive with respect to said cathode and control electrode, said control electrode and anode being shaped whereby to cooperate and provide a substantially uniform accelerating electric field at said cathode surface for initially accelerating electrons at said cathode surface toward said anode to substantially the same velocity in a direction substantially perpendicular to said cathode surface and also providing an electric field in the region between said surfaces which defines an electrostatic lens and at least one additional electrode means along the path of the electron beam at a potential more positive than said anode to provide final acceleration to said beam.

Claim 31

An electron gun for projecting an electron beam comprising a cathode having a surface providing a source of electrons, a control electrode adjacent said cathode and having a surface providing a continuation of said cathode surface, said control electrode being at a potential equal to or more negative than said cathode, an anode spaced from said cathode surface and said control electrode including a surface portion which faces said cathode surface and control electrode surface, said anode being at a potential which is positive with respect to said cathode and control electrode, said control electrode and anode being shaped whereby to cooperate and provide a substantially uniform accelerating electric field at said cathode surface for initially accelerating electrons at said cathode surface toward said anode to substantially the same velocity in a direction substantially perpendicular to said cathode surface and also providing an electric field in the region between said surfaces which defines an electrostatic lens and at least one additional electrode means along the path of the electron beam at a potential more positive than said anode to provide final acceleration to said beam.

Claim 32

A cathode ray tube as in claim 14 including means for applying a control voltage between said cathode and control electrode to control the beam current.