Cathode ray tube employing faceplate-deposited cathodochromic material and electron beam erase

Claim 2

For use in a cathode ray tube, an image screen that comprises a thermal buffer layer of unsensitized particles upon a substrate and a layer of sensitized cathodochromic sodalite supported by the buffer layer and thermally insulated from the substrate by the buffer layer.

Claim 3

A cathode ray tube system adapted to permit electron beam write and erase, that comprises: a cathode ray tube envelope, an image screen that comprises sensitized cathodochromic sodalite material disposed upon a substrate within the envelope; an anode; and electron gun means which produces an electron beam of one exposure to write on the image screen and another, and higher, exposure to directly heat the image screen material and cause erasure; said sensitized cathodochromic sodalite having an erase threshold of the order of 1 joule/cm 2 or less and sufficiently low that during electron beam erase little or no heat is transferred to the substrate.

Claim 4

A cathode ray tube system adapted to permit electron beam write and erase, that comprises: a cathode ray tube envelope, an image screen that comprises sensitized cathodochromic sodalite material disposed upon a substrate within the envelope; an anode; and electron gun means which produces an electron beam of one exposure to write on the image screen and another, and higher, exposure to directly heat the image screen material and cause erasure; said sensitized cathodochromic sodalite having an erase threshold of the order of 1 joule/cm 2 or less and sufficiently low that during electron beam erase little or no heat is transferred to the substrate.

Claim 5

A cathode ray tube system as claimed in claim 2 further comprising a thermal buffer layer of unsensitized particles interposed between the said substrate and said sensitized cathodochromic sodalite material.

Claim 6

A cathode ray tube system as claimed in claim 3 in which the unsensitized particles are unsensitized sodalite.

Claim 7

A cathode ray tube system as claimed in claim 4 in which the unsensitized particles have a density of about 0.5 milligrams per square centimeter.

Claim 8

A cathode ray tube system as claimed in claim 3 in which the substrate is conductive and forms a portion of the anode circuit of the cathode ray tube.

Claim 9

A cathode ray tube system as claimed in claim 3 in which the substrate is non-conductive and in which a layer of conductive material is disposed upon the substrate to form a portion of the anode circuit of the cathode ray tube.

Claim 10

A cathode ray tube system as claimed in claim 2 in which the substrate is the faceplate of the cathode ray tube envelope.

Claim 11

A cathode ray tube system as claimed in claim 2 in which the electron gun means provides an electron beam focused to a size of about 10 mils at the image screen and the intensity of the beam is about 10 5 watts/in 2 .

Claim 12

A cathode ray tube system as claimed in claim 9 in which the electron gun means provides an electron beam whose sweep, when acting to erase the screen, is much slower than the sweep used to write on the screen.

Claim 13

A cathode ray tube system as claimed in claim 2 in which the electron gun means provides a beam which raster scans to erase the screen, the center-to-center separation between successive lines in the raster in combination with the beam width and exposure being such that the overall screen temperature between successive lines is above the erase value.

Claim 14

A cathode ray tube system as claimed in claim 2 in which the sodalite material comprises Na 6 Al 6 Si 6 O 24 .sup.. 2(1-z)NaX, wherein X is chosen from the group consisting essentially of bromine and mixtures of bromine and OH, z is the number of NaX vacancies, and 0<z-1.