(19)
(11) EP 0 172 343 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
07.09.1988 Bulletin 1988/36

(43) Date of publication A2:
26.02.1986 Bulletin 1986/09

(21) Application number: 85107332

(22) Date of filing: 13.06.1985
(84) Designated Contracting States:
DE FR GB NL

(30) Priority: 22.08.1984 JP 17343384

(71) Applicant: DATA GENERAL CORPORATION
 ()

(72) Inventors:
  • Katayama, Hideji
     ()
  • Katoh, Keisuke
     ()
  • Kita, Junya
     ()
  • Shimada, Motowo
     ()

   


(54) Digital contrast control circuit for display unit


(57) digital contrast control circuit for a display unit according to the present invention has an up/down counter (45) for performing up- or down-count operations in response to a contrast control key signal supplied from a contrast control key arranged on a keyboard (43). A digital contrast output from the up/down counter is supplied to a D/A converter (49) arranged within a liquid crystal display unit (47). The D/A converter converts the digital contrast output to an analog contrast signal.






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