Victor Company of Japan, Limited

Toshio Kobayashi

Hideo Hishiki

Masaaki Ito

A convergence correction apparatus comprises a pair of horizontal deflecting coils and a pair of vertical deflecting coils constituting a deflection yoke of a self-convergence system color picture tube, saturable reactors for correcting convergence error in horizontal lines by varying a distribution of a horizontal deflection magnetic field with time, auxiliary control coils coupled to the vertical deflecting coils and wound of the saturable reactors for varying inductances of coils of the saturable reactors by auxiliary control magnetic fields generated by the auxiliary control coils, and a correcting circuit for supplying to the auxiliary control coils a current which has a waveform other than a sawtooth waveform and has a period equal to the vertical deflection period, and for non-linearly varying magnitudes of the auxiliary magnetic fields generated thereby.

Convergence correction apparatus

In a deflection yoke of self-convergence system for use with in-line type color picture tube, the intensity of a magnetic field, which causes the change in impedance of coils of saturable reactors respectively connected in series with two horizontal deflecting coils, is increased so that the variation rate of the inductance expressed in terms of a differential coefficient has the relationship of .theta.e/.theta.m.ltoreq.0.5 wherein .theta.m is a differential coefficient around the center of the picture where the degree of vertical deflection is very small and .theta.e is a differential coefficient at top and bottom sides of the picture where the degree of vertical deflection is maximum. In one embodiment, an auxiliary coil connected to the vertical deflection coils is employed in each of the saturable reactors so as to increase the intensity of the magnetic field applied to the saturable reactors. In another embodiment, metallic member(s) is/are arranged to be close to the saturable reactors so as to reduce reluctance.

Picture correcting apparatus for use with in-line type color picture tube

In a deflecting yoke of an in-line type color picture tube, a pair of saturable reactors responsive to vertical deflection is connected to the horizontal deflecting coils so that horizontal deflection currents respectively flowing in two horizontal deflecting coils are controlled differentially in accordance with the degree of the vertical deflection, thereby minimizing raster distortion. Each of the saturable reactors may comprise a series connection of two coils connected to the vertical deflecting coils, and another series connection of two coils connected to the horizontal deflecting coils. The first-mentioned series connection may be omitted by positioning the second-mentioned series connection so that leakage flux from the vertical deflecting coils can be picked up. The core or cores of each of the saturable reactors are magnetically biased by a permanent magnet. A single disk-like magnet may be rotatably held to be in contact with two parallel cores so that rotation of the magnet results in change in impedance of the reactor.

Device for correcting an image on a picture tube having in-line electron

In a deflecting yoke of an in-line type color picture tube, a pair of saturable reactors responsive to vertical deflection is connected to the horizontal deflecting coils so that horizontal deflection currents respectively flowing two horizontal deflecting coils are controlled differentially in accordance with the degree of the vertical deflection, thereby minimizing raster distortion. Each of the saturable reactors may comprise a series connection of two coils connected to the vertical deflecting coils, and another series connection of two coils connected to the horizontal deflecting coils. The first-mentioned series connection may be omitted by positioning the second-mentioned series connection so that leakage flux from the vertical deflecting coils can be picked up. The core or cores of each of the saturable reactors is magnetically biased by means of a permanent magnet. A single disk-like magnet may be rotatably held to be in contact with parallel arranged two cores so that rotation thereof results in change in impedance of the reactor.

A saturable reactor having a pair of series coils is attached to the outside surface of the cores of the vertical deflecting coils where the series coils are connected in series with a parallel connection of the horizontal deflecting coils. Each of the pair of coils of the saturable reactor is wound around a drum core which is magnetically biased by means of a permanent magnet. The saturable reactor is positioned so that leakage flux from the vertical deflecting coils is led into the drum cores, thereby changing the inductance of the pair of coils in accordance with the degree of vertical deflection. The horizontal deflecting currents flowing through the horizontal deflecting coils thus controlled to chage the width of raster providing a trapezoidal raster which is needed for projecting a TV picture on a large screen.

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Noda, Japan

Toshio Kobayashi