Abstract: An electron tube provided with a semiconductor cathode for emitting electrons, which semiconductor cathode is arranged on a support, a source being arranged in the vicinity of the cathode, in particular, so as to face the free (Si) surface of the cathode, which source is capable of evolving, at the increased temperatures occurring during evacuation of the tube in the manufacturing process, a reducing agent such as F2 or HF, which passivates the free (Si) surface of the cathode.

Abstract: An electron tube provided with a semiconductor cathode for emitting electrons, which semiconductor cathode is arranged on a support, a source being arranged in the vicinity of the cathode, in particular, so as to face the free (Si) surface of the cathode, which source is capable of evolving, at the increased temperatures occurring during evacuation of the tube in the manufacturing process, a reducing agent such as F2 or HF, which passivates the free (Si) surface of the cathode.

Abstract: A property of a layer of a phosphor screen on a substrate is determined by sending a beam of infrared radiation through the substrate and the layer and measuring, after the passage, the intensity of the beam. The radiation can be measured by a CCD camera.

Abstract: A property of a layer of a phosphor screen on a substrate is determined by sending a beam of infrared radiation through the substrate and the layer and measuring, after the passage, the intensity of the beam. The radiation can be measured by a CCD camera.

Abstract: Cathode ray tube comprising an electron gun which is constructed in such a way that the gas pressure near the electron-emissive layer (30) of the cathode is lower than in the other parts of the tube. This can be achieved by reducing the aperture between the G1 (33) and G2 (36), by providing the G2 (36) with a skirt (43). The wall of the skirt, the G1 and the G2 may also be at least partly coated with a getter (41).

Abstract: In an electron tube based on a cold cathode, a cesium source (17) containing Csx—Auy or Csx—Sby is provided near the cold cathode (7), preferably in contact with the first grid (9). Cesium is introduced into the source during activation of the tube. The vapor pressure of the cesium compounds is such that proper delivery of cesium is guaranteed throughout the life-time of the cathode.

Abstract: Semiconductor device with a semiconductor cathode having an emissive part (pn junction) separated from a contact part which has locations at which a controlled breakdown occurs on a contact part metallization at excessive voltages, so that, during manufacture and operation, the emissive part in an election tube is protected from damage.

Abstract: Electron-optical device having two elongate emitting regions arranged symmetrically with respect to a longitudinal axis for producing two electron beams having an elongate cross-section. By means of electron grids, the two beams are focused at the same point of an electron target arranged transversely to the longitudinal axis and having a short central axis and a long central axis. The elongate emitting regions have their smallest cross-section parallel to the scanning direction of a device, cooperating with the electron-optical device, for scanning a target arranged transversely to the longitudinal axis.

Abstract: An electron has an electron-emitting region, a longitudinal axis and an arrangement of apertured electron grids along the axis. A first grid has an aperture for passing electrons, which aperture is located further outwards with respect to the longitudinal axis than the emitting region. One of the other grids is provided with a shield so as to shield the edge wall of the aperture, if it is located within direct view of the electron-emitting region, from incidence of positive ions.