| 313 / | HD | ELECTRIC LAMP AND DISCHARGE DEVICES |
| 364 | DF | CATHODE RAY TUBE {11} |
| 441 | DF | .~ Ray generating or control {6} |
| 446 | DF | .~.~ Including cathode assembly {2} |
| 452 | DF | .~.~.~ With focus electrode adjacent cathode {2} |
| 454 | | .~.~.~.~ Nonplanar cathode {1} |
| 455 | DF | .~.~.~.~.~> Brillouin beam type |