Sony Corporation

Hiroyuki Sumiya

Masao Suzuki

Seiichi Ogawa

Toshinobu Ohnishi

The beam forming means and static convergence correcting means in a color cathode ray tube are arranged to provide for proper convergence of the beams at regions remote from the center of the screen and closer to the corners. The resulting misconvergence at the center of the screen is then corrected by dynamic convergence correcting means which produces less beam distortion then if it had to correct misconvergence at the corners.

Convergence means for color cathode ray tube

Apparatus for detecting an error condition in a deflection circuit of a cathode ray tube, the deflection circuit being of the type wherein a periodic retrace signal is generated, including a filter coupled to the retrace signal generator and normally non-responsive to the retrace signal. In the event of an error condition, the retrace signal is provided with higher frequency components which are transmitted by the filter. An output signal generator is coupled to the filter to produce an output signal in response to the signal components transmitted by the filter. In one embodiment, the deflection circuit is the horizontal deflection circuit of a CRT wherein the retrace signal is used to produce the high voltage for the CRT. In this embodiment, the output signal is used to vary the repetition frequency of the horizontal oscillating signal applied to the deflection circuit so as to correspondingly change the amplitude of the retrace signal and, thus, to reduce the magnitude of the high voltage.

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Fussa, Japan

Hiroyuki Sumiya