Cathode ray tube

• Main Authors: P.H.F. TROMPENAARS, N.C. VAN DER VARRT, G.G.P. VAN GORKOM
• Format: Patent
• Language: English
• Published: 14.11.2001
• Edition: 7
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

A cathode ray tube comprising an electron source and an electron beam guidance cavity having an input aperture and an output aperture, wherein at least a part of the wall of the electron beam guidance cavity near the output aperture comprises an insulating material having a secondary emission coefficient delta1 for cooperation with the cathode. Furthermore, the cathode ray tube comprises a first electrode which is connectable to a first power supply for applying, in operation, an electric field with a first field strength E1 between the cathode and the output aperture. delta1 and E1 have values which allow electron transport through the electron beam guidance cavity. The cathode ray tube further comprises a conventional main lens to obtain a spot on a display screen. According to the invention, an electron lens is placed between the exit of the cavity and the main lens for directing the electron beam at a predetermined angle towards the entrance of the main lens.