| 摘要 |
<p>1,238,473. Cathode-ray tube circuits. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 19 Nov., 1968 [22 Nov., 1967], No. 54877/68. Heading H4T. Static convergence of the three beam of a colour display tube is effected by means of respective auxiliary deflection coils supplied with direct currents of adjustable magnitude derived via at least one rectifier from a source of line repetition frequency pulse voltage which is substantially constant during the sweep period, the rectifler(s) being cut-off during fly-back periods and the quotient L/R, where L = the inductance and R = the resistance of the auxiliary deflection coils, i.e. (the time constant) being large relative to the fly-back period. As shown, the line-frequency voltage is supplied with opposite polarities 2, 3 to oppositely poled diodes 6, 7 which pass the seam portion and the derived D.C. voltages is fed via the resistance network shown to produce the required convergence correction currents in the auxiliary deflection coils 1r (Red), 1g (Green), and 1b (Blue), the magnitudes being adjusted by respective potentiometers 8, 9 and 10. Dynamic convergence correction is also provided by means of a purabolically varying A.C. voltage supplied to each end of the auxiliary deflection coils.</p> |
