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

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 V.sub.1 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 V.sub.0 to said deflection yoke means;
• wherein a value of said reverse pulse voltage V.sub.1 is set so that an equation V.sub.01 -V.sub.11 .apprxeq.0 is satisfied, where V.sub.01 is a first alternating voltage proportional to a product (V.sub.0 .times.C.sub.0), C.sub.0 is an electrostatic capacity between said horizontal deflection coil and said interior conductive coating, V.sub.11 is a second alternating voltage proportional to a product (V.sub.1 .times.C.sub.1), and C.sub.1 is an electrostatic capacity between said conductive film electrode and said interior conductive coating;
• and
• wherein an intensity of a very low frequency electric field (VLEF) is decreased to a value no greater than 1 (V/m) at a distance of about 30 cm from and in front of a front surface of said cathode-ray tube.

A cathode-ray tube display unit comprising:

• voltage supplying means for supplying 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 a 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 for generating a first reverse pulse voltage V.sub.1 having a polarity reverse to that of voltage generated in said interior conductive coating due to an electrostatic coupling generated by a flyback pulse voltage V.sub.0 supplied to said deflection yoke means;
• means for generating a second reverse pulse voltage V.sub.3 having a polarity inverted from that of A.C. components generated at an output of said voltage supplying means;
• means for adding said first reverse pulse voltage V.sub.1 and said second reverse pulse voltage V.sub.3 to each other;
• and
• means for supplying an output of said adding means to said conductive film electrode, wherein an electrostatic capacity between said horizontal deflection coil and said interior conductive coating means is C.sub.0 and an electrostatic capacity between said conductive film electrode and said interior conductive coating is C.sub.1, and the relationship (V.sub.0 .times.C.sub.0)>((V.sub.1 +V.sub.3).times.C.sub.1) is satisfied.

A cathode-ray tube display unit comprising:

• high voltage transformer 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;
• means for generating a first reverse pulse voltage having a polarity inverted from that of flyback pulse voltage generated in said horizontal deflection coil;
• means for supplying said first reverse pulse voltage to said interior conductive coating through an electrostatic capacity;
• means for generating a second reverse pulse voltage having a polarity inverted from that of A.C. components generated at an output terminal of said high voltage transformer means;
• means for adding said first reverse pulse voltage and said second reverse pulse voltage to each other;
• and
• means for supplying an output of said adding means to said interior conductive coating through the electrostatic capacity.