Browse Prior Art Database

Character Generator

IP.com Disclosure Number: IPCOM000075667D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Harris, TJ: AUTHOR

Abstract

This character generator produces display beams from a hologram matrix external to the display tube, whereas the size of the characters on display can be changed.

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Character Generator

This character generator produces display beams from a hologram matrix external to the display tube, whereas the size of the characters on display can be changed.

Hologram plate 14 stores a character set which consists of a plurality of holograms 13. Plate 14 is located external to vacuum envelope 16 and may be readily changed. Control 12 causes selector 10 to select the appropriate hologram 13 on plate 14. The reconstructed image produced by the selected hologram 13 is directed to the center of photo-cathode 20, independent of the position of hologram 13 on plate 14, Photocathode 20, which is mounted within envelope 16, emits electrons with a pattern identical to that displayed upon it by the reconstructed image. Zoom lens 37 varies the size of the electron image from photo cathode 20, by varying the potential on electrodes 39 through variable field-control unit 38 which is controlled by control 12.

Image current amplification to improve the brightness of the character on target 36, is performed by dynodes 40, 41, 43, 44 and 45. The dynodes are thin screens, each consisting of an aluminum oxide supporting film coated on the emitter side with a thin-metal film on which potassium chloride or barium fluoride is deposited. The primary electrons from lens 37 penetrate the aluminum oxide and the conducting film of dynode 40. This excites electrons in the material, some of which have sufficient energy to escape into the vacuum as secondary electrons...