Browse Prior Art Database

Displaying Information On A CRT

IP.com Disclosure Number: IPCOM000096893D
Original Publication Date: 1962-Jan-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Weber, EV: AUTHOR

Abstract

The display of large quantities of information on a cathode ray tube at rates sufficiently great to eliminate flicker requires the use of electrostatic deflection. If the display is large, transistor circuitry cannot be used in conjunction with standard electrostatic deflection cathode ray tubes due to the required large deflection voltages. A cathode ray tube using electrostatic deflection for high frequencies and electromagnetic deflection for low frequencies, however, permits compatibility with transistor circuitry. Good large deflection sensitivity is then obtained for character positioning, while fast rise time, small deflections for character writing are possible.

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Displaying Information On A CRT

The display of large quantities of information on a cathode ray tube at rates sufficiently great to eliminate flicker requires the use of electrostatic deflection. If the display is large, transistor circuitry cannot be used in conjunction with standard electrostatic deflection cathode ray tubes due to the required large deflection voltages. A cathode ray tube using electrostatic deflection for high frequencies and electromagnetic deflection for low frequencies, however, permits compatibility with transistor circuitry. Good large deflection sensitivity is then obtained for character positioning, while fast rise time, small deflections for character writing are possible.

Cathode ray tube 1 has electrostatic plates 2 that scan a small raster area which is deflected to any position by magnetic deflection coils 3. Varying x and y analogue voltages derived from character generators 4 and 5 are applied to plates 2 to cause the beam to write the desired corresponding character on screen 6.

Character positioning on screen 6 is accomplished by horizontal and vertical ramp generators 7 and 8 through coils 3 which move the beam about screen 6 in a raster fashion. Electrostatic deflection plates may be substituted for coils 3. Similarly, magnetic deflection coils may be substituted for plates 2. A small corrective voltage is applied from corrector ramp 9 through the horizontal electrostatic amplifier 10 for cancelling the magnetic beam deflect...