Hitachi, Ltd.

Machio Kawashima

Takeshi Nakayama

Kuniharu Osakabe

Takehiko Nishimoto

Kozi Takahashi

Koji Takahashi

Kunisuke Kasagi

There is provided an in-line color picture tube apparatus with a dynamic convergence correction device. Dynamic convergence correction means is disposed between a self-convergence deflection yoke and a static convergence correction magnet assembly which are mounted on the neck portion of the tube. The dynamic convergence correction means comprises a support member made of a non-magnetic substance, eight coil assemblies having cores fixedly disposed on the support member concentrically of the tube axis with mutual equal circumferential spacings, and coils wound on the cores. The coils are connected in such a manner as to generate a four-pole magnetic field having a horizontal axis, a six-pole magnetic field having the horizontal axis, four-pole magnetic field having an axis making an angle of 45.degree. with respect to the horizontal axis, and a six-pole magnetic field having a vertical axis. Dynamic convergence correction signals of predetermined amplitude and direction are fed to the coils at predetermined timings in accordance with the deflection synchronizing signal.

In-line color picture tube apparatus with dynamic convergence correction

A color television receiver includes a color picture tube having three electron guns including cathodes and heaters therefor, respectively, and an automatic cutoff adjusting circuit for adding a reference voltage signal substantially at a black level to a luminance signal during an interval beginning substantially at the end of a vertical blanking period, and for detecting cathode currents flowing toward the cathodes during the above-described interval to control cathode voltages for the cathodes for keeping the cathode currents at a predetermined level by way of feedback of voltages proportional to the cathode currents. There is provided a circuit for applying a positive voltage to each of the heaters during the above-described interval to reduce a potential difference between the heater and corresponding one of the cathodes to thereby lower a leakage current flowing between the cathode and the heater.

Color television receiver

A color picture tube having a shadow mask is disclosed in which, with a view to making occurrence of moire imperceptible, electron beam transmissive apertures of the shadow mask are formed in such an array that a plurality of trains of the electron beam transmissive apertures each arrayed in the vertical direction with a pitch P.sub.y are juxtaposed to one another, wherein, assuming that the order of the harmonics is represented by n and m is an odd number smaller than 2n, there exist the relations (n-0.5)P.sub.l .ltoreq.P.sub.y .ltoreq.(n+0.05)P.sub.l and (m-0.35)P.sub.y /2n.ltoreq..DELTA.y.ltoreq.(m+0.35)P.sub.y /2n among the pitch P.sub.y, pitch P.sub.l of scanning lines and vertical deviation .DELTA.y between two adjacent apertures in the horizontal direction.

Slotted shadow mask having apertures spaced to minimize moire

A color picture tube having a shadow mask provided with a plurality of vertical aperture rows arranged as horizontally juxtaposed to one another, each vertical row comprising the electron beam transmissive apertures vertically arranged in line with a predetermined pitch P.sub.y. With a view to making possibly occurring moires imperceptible, the arrangement of the apertures are made such that, when spatial deviation in the vertical positions between any two apertures in the horizontally adjacent aperture rows is represented by .DELTA.y, there may be included combinations of at least two different type aperture rows of different deviations .DELTA.y which satisfy the following condition ##EQU1## at least when n is equal to 1, 2, 3 or 4 and k is an odd number smaller than 2n.

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Mobara, Japan

Machio Kawashima