| 摘要 |
1,078,986. Colour television tubes. RADIO CORPORATION OF AMERICA. April 21, 1965 [April 23, 1964], No. 16886/65. Heading H1D. In a three-gun, shadow-mask, colour kinescope, precise static beam convergence is obtained by means of two pairs of magnets 21a, 21b, 23a, 23b arranged adjacent diametrically-opposed portions of the tube neck and mounted for simultaneous movement away from or towards the tube axis. One magnet pair is always nearer the tube axis than the other pair and is adjacent one gun, e.g. the blue gun, with S or N poles adjacent, while the other magnet pair is between the red and green guns with N or S poles adjacent, respectively. The magnet assembly produces a lateral deflection of the blue beam and smaller, opposite deflections of the red and green beams. The magnets may be arranged between a colour purity adjusting structure, e.g. a pair of rotatable magnetic rings, and a mount for scanning coils and conventional beam convergence apparatus. As shown, the magnets 21, 23 are glued to holders 58 extending through slots in a support 50, 52a, 52b asymmetrically disposed about the tube neck around a member 40 having a crescent-shaped web 42. Magnet holders 58 have pins engaging in spiral slots 72a, 72b of a cam 70, rotation of which moves the magnets away from or towards the tube axis. The positions of magnet pairs 21, 23 may be reversed by rotating support 50 through 180 degrees about member 40 to reverse the direction of deflection of the blue beam. |
