Recent developments in Plumbicon ® pickup tubes

The state of the art of vidicon type camera tubes was greatly enhanced several years ago following the successful development of a long-life, high-quality lead oxide photosensitive target material and its introduction into the Plumbicon pickup tube. Since then the original Plumbicon has become the standard camera-tube in the color-television broadcast industry. Recent developments have now resulted in improved versions of the Plumbicon-- types that have improved wave-length sensitivity, lag, resolution, smaller size, and various electron optics. In addition, the Plumbicon is now being successfully manufactured in this country for the first time. In this paper a review will be given of the operating principles of the standard lead oxide photosensitive layer, of its properties, and of the unique characteristics which result when this layer is used as the target in an electron-beam-scanned pick-up tube. Electron-optically the Plumbicon operates in the same fashion as a vidicon; hence it is sensible that we present a detailed comparison between the Plumbicon and the antimony trisulfide vidicon, which will illustrate the superiority of the Plumbicon as regards dark-current, lag, transfer-characteristics, etc. The characteristics of the recently introduced "extended red sensitive" Plumbicon- the XQ 1023- will be presented. This tube has a sensitivity of >450 µA/1m (more than 50% greater than the standard XQ 1020 Plumbicon) with useful spectral-response out to beyond 8500Å, a limiting resolution of greater than 700 TV lines, with greater than 50% modulation depth (central) at 400 TV lines. Information about other recent developments in Plumbicon layers, size, and electron optics will also be described.