Abstract: A virtual remote cathode has the position of a space charge cloud associated with it fixed by the geometry of a fixed insulating plate. The plate can be made to accurate dimensions and hence the cathode to control grid dimension can be accurately controlled and will not change as a result of any mechanical, electrical or physical changes in the construction. The fixed insulating plate is located on a surface of the control grid facing the cathode.

Abstract: A display device includes field emission cathode apparatus for emitting electrons. A plurality of electron beams are formed from the field emission cathode apparatus. A screen, which has a phosphor coating facing the cathode receives the plurality of electron beams. The phosphor coating includes a plurality of pixels each corresponding to a different one of said plurality of electron beams. A grid electrode is disposed between the cathode and the screen for controlling the flow of electrons from the cathode. The field emission cathode includes extractor grid means, having a plurality of separately addressable portions associated with each of said plurality of pixels. A gamma transfer function between input data value and beam current is provided in order to emulate a conventional CRT. This can be achieved by use of a lookup table.

Abstract: A display device having a screen is provided in which a back-plate is sealed to the screen to form an evacuated chamber. An area cathode is disposed between the back-plate and the screen. A permanent magnet is disposed between the cathode and the screen. A two dimensional array of rows and columns of channels extends between opposite poles of the magnet for receiving electrons from the cathode. An anode phosphor layer is disposed between the screen and the magnet for receiving electrons from the channels. A grid electrode between the area cathode and the magnet controls flow of electrons from the cathode into the channels, whereas an anode between the magnet and the anode phosphor layer controls flow of electrons from the channels towards the screen. In a preferred embodiment, the cathode means comprises the backplate and a silica glass substrate peripherally sealed to the back-plate to produce a chamber in which a gas is contained.

Abstract: Display apparatus comprises a connection for releasably connecting a display device (130;130') to the display apparatus. A data input (MON.sub.-- ID) receives first data from a first releasable connection (ST) to the display device (130;130') and for receiving second data from a second releasable connection (ID) to the display device (130;130'). Switch (320) selectively connects the data input (MON.sub.-- ID) to either of the first releasable connection (ST) and the second releasable connection (ID). Display processor logic (310) is connected to the switch (320) for generating one or more video signals to generate an image on the display device (130,130') as a function of the data directed to the data input (MON.sub.-- ID) from the display device (130;130') by the switch (320).