Display device

• Main Authors: JOHN BEETESON, ANDREW RAMSAY KNOX
• Format: Patent
• Language: English
• Published: 28.02.2001
• Edition: 7
• Subjects: ADVERTISING; ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICESUSING STATIC MEANS TO PRESENT VARIABLE INFORMATION; BASIC ELECTRIC ELEMENTS; CRYPTOGRAPHY; DISPLAY; EDUCATION; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION; SEALS

Display device comprising a cathode 20, a permanent magnet 60, a two dimensional array of rows and columns of channels 70 extending between opposite poles of the magnet for receiving electrons from the cathode. A screen 90 has a plurality of phosphor pixels 80 each corresponding to a different channel where the pixels may be made up of a plurality of sub-pixels. Grid electrode 40 is disposed between the cathode and the magnet whilst anode means 50 is disposed between the screen and the magnet. Anode means 50 may comprise a plurality of pairs of anodes extending parallel to the columns of channels and each pair having first and second anodes extending along opposite sides of the corresponding column of channels. A focus electrode 120 is disposed between the screen and the anode means and may comprise a plane electrical conductor having slots aligned with a different column of channels. Control signals are supplied to the grid electrode to selectively control the flow of electrons from the cathode through each channel to the corresponding pixel. An anode drive circuit supplies anode drive signals to the anode means for accelerating electrons through the channels. The anode drive signals may comprise deflection signals to sequentially deflect electrons emerging from each channel towards different sub-pixels of the corresponding pixel. A focus drive circuit supplies a signal to the focus electrode to focus the electrons emerging from the channels onto the screen. The focus electrode may be driven with a parabolic waveform. The beams of electrons travelling from the cathode means to the screen may be rotated by varying the signal supplied to the focus electrode.