| 摘要 |
627,063. Cathode-ray tubes. RAULAND CORPORATION. Jan. 2, 1947, No. 162. Convention date, July 23, 1946. [Class 39 (i)] A cathode-ray tube with an ion filtering screen is provided with additional means foi collecting fringing electrons of low velocity which result from the presence of the ion filter. A diaphragm with a central aperture will remove the low velocity electrons when the ion filter 7, e.g. of aluminium is placed well inside the anode tube of the electron gun, or, alternatively, as shown in Fig. 3a, a series of fine-mesh electrodes are placed closely adjacent the ion filter 6, 7, the first and third 13, 16 being connected to the anode and the middle one, 14, connected to a source of low potential, e.g. the second grid or cathode of the tube. The mesh electrodes may be replaced by perforated diaphragms. The ion filter may be made by evaporating the metal, e.g. aluminium, on to a mould or thin plastic membrane which is later dissolved away. In a modification, the ion filter is located between the gun and the fluorescent screen, a screen grid collecting the fringing electrons. |
