Cathode ray tube apparatus

Claim 2

Cathode ray tube apparatus including an electron beam source, an electroluminescent screen, a beam-directing electrode spaced from the screen and including an insulating support sheet, a series of parallel strips of conductive material on the support sheet and resistor elements interconnecting the ends of the strips to provide a series connection; the electron beam source being arranged to launch an electron beam into the space between the screen and the beam-directing electrode, means to connect beam-directing potentials between the screen and the beamdirecting electrode to provide a beam-directing field in the space between them for directing the electron beam towards the screen and means to deflect the beam in two directions arranged to be operative upon the beam before it enters the space.

Claim 3

Cathode ray tube apparatus according to claim 1 wherein the resistor elements are graded to provide a non linear distribution of voltage drop of a potential applied between the ends of the series circuit throughout the series circuit.

Claim 4

Cathode ray tube apparatus according to claim 1 having a second electroluminescent screen parallel to and luminescent in a colour different from that of the first mentioned electroluminescent screen, a second electron beam source and a second beam-directing electrode spaced from the second screen, the second electron beam source being arranged to launch an electron beam into the space between the second screen and the second beam-directing electrode, and means to connect beam-directing potentials between the second screen and the second beam-directing electrode to provide a beam-directing field in the space between them for directing the beam from the second source towards the second screen and second means to deflect the beam from the second source in two directions arranged to be operative upon the second beam before it enters the space between the second screen and the second beam directing electrode.

Claim 5

Cathode ray tube apparatus according to claim 1 having a second electroluminescent screen which is parallel to the first mentioned screen, a second beam-directing electrode spaced from the second screen, and means to connect beam-directing potentials between the second screen and the second beam-directing electrode to provide a beam-directing field in the space between them for directing the electron beam towards the second screen, wherein the means to deflect the beam in two direction is arranged to deflect the beam in either the space between the first mentioned screen and beam-directing electrode or the space between second mentioned screen and beam-directing electrode.

Claim 6

Cathode ray tube apparatus according to claim 1 having a second electroluminescent screen parallel to and luminescent in a colour different from that of the first mentioned electroluminescent screen, a second electron beam source and a second beam-directing electrode spaced from the second screen, the second electron beam source being arranged to launch an electron beam into the space between the second screen and the second beam-directing electrode, and means to connect beam-directing potentials between the second screen and the second beam-directing electrode to provide a beam-directing field in the space between them for directing the beam from the second source towards the second screen and second means to deflect the beam from the second source in two directions arranged to be operative upon the second beam before it enters the space between the second screen and the second beam directing electrode.

Claim 7

cathode ray tube apparatus according to claim 5 including an electroluminescent screen support having a serrated surface with faces angled in two directions, wherein the second electroluminescent screen is formed upon the faces of the screen support which are angled in one direction, a third electroluminescent screen is formed upon the faces of the screen support which are angled in the other direction, a third electron beam source arranged to launch an electron beam into the field space between the support for the second and third electroluminescent screens and the second beam directing electrode to direct the electron beam therefrom towards the third electroluminescent screen, and third means to deflect the beam from the third source in two directions before it enters the space between the second beam directing electrode and the screen support for the second and third electroluminescent screens, the three luminescent screens each being luminescent in a different colour when bombarded by electrons.

Claim 8

A cathode ray tube according to claim 1 including an electron beam reversing lens arranged in the path of the beam of electrons between the electron gun and the said space, the arrangement of the electron gun, the reversing lens and the space being such that a beam of electrons which is undeflected by the said means for deflecting in passing from the gun through the reversing lens to the space enters the space in a direction which is parallel but opposite to that in which it was emitted from the gun.

Claim 9

A cathode ray tube according to claim 1 including a second beam-directing system arranged in the path of the beam between a first means for deflecting the beam in one of the orthogonal directions and a second means for deflecting the beam in the other orthogonal direction to change the direction of the beam.