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Cathode-ray tube display unit in which unwanted radiant electric field from face plate of cathode-ray tube is decreased

  • US 5,689,157 A
  • Filed: 10/18/1995
  • Issued: 11/18/1997
  • Est. Priority Date: 05/08/1992
  • Status: Expired due to Fees
First Claim
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1. A cathode-ray tube display unit comprising:

  • voltage supplying means for supplying at least a high voltage to an anode of a cathode-ray tube;

    deflection yoke means having a horizontal deflection coil and a vertical deflection coil;

    an interior conductive coating formed on the inside of a glass vessel of said cathode-ray tube;

    a conductive film electrode formed on an external wall surface of the glass vessel of a funnel portion of the cathode-ray tube, said conductive film electrode being electrically separated from an exterior graphite coating formed on an external wall surface of said cathode-ray tube, said exterior graphite coating being electrically connected to ground; and

    means connected to said conductive film electrode for generating a reverse pulse voltage V1 having a polarity reverse to that of a voltage generated in said interior conductive coating due to an electrostatic coupling generated by a flyback pulse voltage V0 supplied to said deflection yoke means, wherein a value of said reverse pulse voltage V1 is set so that an equation V01 -V11

    0 is satisfied, where V01 is a first alternating voltage proportional to a product (V0 ×

    C0), C0 is an electrostatic capacity between said horizontal deflection coil and said interior conductive coating, V11 is a second alternating voltage proportional to a product (V1 ×

    C1), and C1 is an electrostatic capacity between said conductive film electrode and said interior conductive coating means.

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