Patent ID: 6326745
Filing Date: 2001-12-04
Classification: H01J,H04N

Abstract:
A cathode-ray tube apparatus comprising:a vacuum envelope including a substantially rectangular panel having a phosphor screen on an inner surface thereof and having a horizontal and a vertical axis, a funnel fixed to the panel, and a neck connected to a reduced-diameter portion of the funnel;an electron gun arranged in the neck, for emitting electron beams towards the phosphor screen;a deflecting yoke mounted on the reduced-diameter portion of the funnel and on the circumference of the neck, for deflecting the electron beams so that the phosphor screen is scanned in the horizontal and vertical directions, the deflecting yoke having horizontal deflecting coils for deflecting the electron beams in the horizontal direction, and vertical deflecting coils for deflecting the electron beams in the vertical direction; anda modulator having saturated coils connected to the horizontal deflecting coils, a saturating control coils connected to the vertical deflecting coils, saturable cores around which the saturated coils or the saturating control coils are wound, and magnets biasing the saturable cores magnetically,wherein the modulator has different settings in an intermediate portion and in peripheral portions of a picture formed on the phosphor screen so that the change of inductance of the saturating control coils in the horizontal axis direction compensates the difference of North-South distortion between the intermediate portion and the peripheral portions of the picture with respect to the vertical axis direction.