| 摘要 |
496,018. Cathode-ray tubes. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. March 2, 1938, No. 6571. Convention date, March 5, 1937. [Class 39 (i)] An iconoscope screen comprises a " signal " layer deposited on a mica or other dielectric, or a dielectric layer of alumina, magnesia, silica or the like on a metal plate, the layer of sensitized mosaic particles, and a " braking " layer of aluminium, platinum, gold or chromium covering the voids between the particles which has a lower capacity of emitting secondary electrons than the dielectric and which does not electrically connect the sensitive particles. The " braking " layer must be thick enough to prevent the scanning electrons reaching and exciting the dielectric and sufficiently thin to have a large resistance. The " braking " layer should not be oxidized to a depth of more than 20 atoms and may, in the case of aluminium, be 100 atoms thick. It may be deposited on the dielectric layer, either before or after the sensitive particles have been deposited, by vaporizing from tungsten wire in an exhausted space. It is stated that if the braking layer extends under the sensitive particles it prevents them coalescing during manufacture. |
