Hitachi, Ltd.

Hitachi Media Electronics Co., Ltd.

Hitachi Mizusawa Electronics Co.

Yoshio Satoh

Soichi Sakurai

Hiroshi Yoshioka

Nobutaka Okuyama

Masao Obara

Kooji Fukuma

Hiroshi Jitsukata

Atsushi Takeyama

Naoki Ito

Yoshihiro Obara

Takanori Yukimatsu

Katsuyuki Kawakami

A cathode ray tube display device including unnecessary radiating magnetic field reducer which improves the ability to reduce an unnecessary radiating magnetic field, especially, generated by a vertical deflection coil. A pair of coil is disposed in opposing relationship on the opposite sides of the ferrite core along an X-axis or in the horizontal direction of the deflection yoke so as to be in contact with an open side end of the ferrite core. Each coil has a shape curved with a predetermined radius of curvature conforming to the shape of the outer peripheral surface of the ferrite core. The ferrite core acts as a magnetic material for the coils which reduces the unnecessary radiating magnetic fields to increase the coil inductances to thereby produce a large extremely low frequency magnetic field (ELMF) reducing effect.

Deflection yoke with coils for reducing unwanted magnetic field radiation

A cathode-ray tube display unit provided with a high voltage transformer for supplying high voltage to an anode of a cathode-ray tube, a deflection yoke having a horizontal deflection coil and a vertical deflection coil, and an interior conductive coating formed on the inside of a glass vessel of the cathode-ray tube, in which there is provided an electrode in the conductive coating form formed on an external wall face of a glass vessel at a funnel portion being electrically separated from an exterior graphite coating formed on an external surface of the cathode-ray tube and connected to ground, and a circuit for applying reverse pulse voltage V.sub.1 that satisfies (V.sub.0 .times.C.sub.0)&gt;(V.sub.1 .times.C.sub.1) to the electrode in the conductive coating form is included. Where, it is assumed that flyback pulse voltage supplied to the deflection yoke means is V.sub.0, reverse pulse voltage having a polarity reverse to that of voltage generated in the interior conductive coating is V.sub.1, electrostatic capacity between the horizontal deflection coil and the interior conductive coating is C.sub.0, and electrostatic capacity between the electrode in the conductive coating form and the interior conductive coating is C.sub.1.

Cathode-ray tube display unit in which unwanted radiant electric field

A color cathode-ray tube which includes a deflection yoke having a convergence correcting device and an electron gun provided to the deflection yoke for generating a multiplicity of electron beams. In the deflection yoke, a vertical deflection coil is made up of at least a pair of saddle type coil halves each divided into at least first and second coil parts, the first coil parts of the coil halves and the second coil parts thereof are connected respectively mutually in series or parallel, a subcore having a vertical auxiliary deflection coil is provided on a side of the electron gun, the vertical auxiliary deflection coil is made up of first and second correction coils for generating 4 polar magnetic field components which are directed at least opposite to each other, a series circuit of a first resistor and the first correction coil is connected in parallel to a series circuit of a second resistor and the second correction coil to form a parallel circuit, the parallel circuit is connected in series with the vertical deflection coil, a shunt circuit is provided for shunting a current flowing through the second coil part to supply the shunted current into the first and second correction coils to thereby cause a predetermined imbalance between the currents flowing through the first and second correction coils, when an area of a display screen other than a predetermined range in a vertical direction is subjected to a vertical deflection. Thereby horizontal and vertical line misconvergences can be corrected.

Deflection yoke and cathode-ray tube apparatus comprising the same

A deflection yoke attached to a color cathode ray tube forming multiple electron beams arranged in line, and in particular a deflection yoke having convergence correction apparatus. Circuit components such as a plurality of resistors, variable resistors, and diodes are connected in parallel with vertical deflection coils. A part of a vertical deflection current flowing through the vertical deflection coils is diverted to the circuit components. Furthermore, the amount of the diverted current is made adjustable so that it will differ between a former part of a vertical deflection period and a latter part thereof. As a result, horizontal line misconvergence at upper and lower ends of the screen can be completely corrected.

Deflection yoke and cathode ray tube having the same

In a color picture tube especially incorporating an in-line dot type shadow mask, the horizontal arrangement of the apertures of the shadow mask is determined to make substantially equal the interdistance between adjacent electron beams formed on the fluorescent screen based on beams of electron passing through apertures at the corners of the shadow mask, thereby making full use of the purity tolerance.

Color picture tube shadow mask

Growing community of inventors

Chiba-ken, Japan

Yoshio Satoh