Cathode ray tube storage device with an electroluminescent display panel

Claim 2

A cathode ray tube storage device including a display panel (26) incorporating a layer of electrolumineacent material (36), means (28) for applying an alternating voltage of predetermined magnitude across said electroluciacsceat material (36), and an electron gun (14) operable to eelectively write a charge pattern over selected regions of the display panel (26), characterised in that the electro- lumineeoent material (36) is of the type having hysteresis loop characteristics whereby two stable states exist for the material at said alternating voltage of predetermined magnitude, said material (36) emitting light when in one of said stable states but emitting no light, or subetntially no light, when in the other of said atates, said stable states being individually selectable in response to electron beam radiation of predetermined intensity from said electron gun (14), and means (16) for controlling the intensity of the electron beam radiation during writing of said charge pattern such that a visible image correspoading to said charge pattern is produced by said display panel (26).

Claim 3

A cathode ray tube storage device as claimed in claim 1, in which said electroluminescent material (36) has a plurality of different light emitting stable atatea at said alternating voltage of predetermined magnitude, each state being individually selecTablo in response to electron beam radiation of predetermined different intensitiee.

Claim 4

A cathode ray tybe storage device as claimed in claim 1 or claim 2, in which said stable states are individually aelectable by direct radiation of said electrolumineacent material (36) with said electron beam of predetermined selected intensity.

Claim 5

A cathode ray tube storage device as claimed in claim 1, 2 or 3, in which said electroluminescent material (36) is sandwiched between two co-extensive layers of conductive material (32,40) separated from said electrolumineacent material (36) by intermediate layers of inaulating material (34,38), said layers of conductive material (32,40), the layers of insulating material (34,38), and the electroluminescent material (36) together with a tube face plate (12) forming the display panel (26), the alternating voltage of predetermined magnitude being applied across said conductive layers (32,40) and at least the layer of conductive material (40) and layer of insulating eatesial (38) towards said electron gun (14) being of a nature to permit direct electron beam radiation of said electroluminescent material (36) therethrough by said electron gun (14).

Claim 6

A cathode ray tube storage device as claimed in claim 1 or claim 2, in which said stable atatea are individually selectable by light radiation of said electroluminescent material (36) induced in an adjacent intermediate layer of cathodoluminescent material (44) in response to direct radiation of said cathodoluminescent material (44) by said electron beam of predetermined selected intensity.

Claim 7

A cathode ray tube storage device as claimed in claim 5, in which said display panel comprises a tube face plate (12), a first layer of conductive material (32) on said face plate (12), a layer of insulating material (34) on said first layer of conductive material (32), said electroluminescent layer (36) on said layer of insulating material (34) a layer of insulating aathodolumineaaent material (44) on said electroluminescent material and a second layer of conductive material (40) on said layer of insulating cathodoluminescent material (44) said panel (26) being incorporated in said device with the second layer of conductive material (40) facing towards the electron gun (14) and being of a nature to permit direct electron beam radiation of said insulating cathodoluminescent material (44) therethrough by said electron gun (14), and said alternating voltage of pre- determined magnitude being applied across said first and second conductive layers (32,40).

Claim 8

A cathode ray tube storage device as claimed in claim 5, in which said display panel comprises a tube face plate (12), a first layer of conductive material (32) on said face plate (12), a first layer of insulating material (34) on said conductive material (32), said layer of electroluminescent material (36) on said insulating material (34), a second layer of insulating material (38) on said electroluminescent material (36), a second layer of conductive material (40) on said second layer of insulating materlal (38), and a layer of cathodoluminescent material (44) on said second layer of conductive material (38), said panel (26) being incorporated in said device with the cathodoluminescent material (44) facing towards the electron gun (14), the second layer of conductive material (40) and the second layer of insulating material (38) being of a nature to permit radiation of said electroluminescent material (36) therethrough by light from said cathodo- luminscent material (44) produced by direct electron beam radiation of said cathodoluminescent material (44) from said electron gun (14), and said alternating voltage of pre-determined magnitude being applied across said first and second conductive layer (32,40).

Claim 9

A cathode ray tube storage device as claimed in claim 5, in which said display panel (26) comprises a tube face plate (12), a first layer of conductive material (32) on said face plate (12), a first layer of insulating material (34) on said conductive material (32), said layer of electroluminescent material (36) on said insulating material (34), a second layer of insulating material (38) on said electroluminescent material (36), a layer of cathodoluminescent material (44) on said second layer of insulating material (38), and a second layer of conductive material (40) on said cathodoluminescent material (44), said panel (26) being incorporated in said device with the second layer of conductive material (40) facing towards the electron gun (14), the second layer of conductive material (40) being of a nature to permit radiation of said cathodoluminescent material (44) therethrough by electron beans radiation from said electron gun (14), said second layer of insulating material (38) being of a nature to permit radiation of said electroluminescent material (36) therethrough by light from said cathodoluminescent material (44) produced by said electron beam radiation, and said alternating voltage of predetermined magnitude being applied across said first and second conductive layers (32,40).

Claim 10

A cathode ray tube storage device as claim in any one of the preceding claims, in which said means (26) for applying an alternating voltage of predetermined magnitude forms part of a resonant circuit having a variable inductive load (25) and means (30) for selecting the value of the inductive load (25) in accordance with the value of the capacitive load of the face plate (26).

Claim 11

A cathode ray tube storage device as claimed in claim 9, in which said means (30) for selecting the inductive load is operated by a switching circuit (31) controlled by the grid voltage of the electron gun (14).