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the first television camera tube with storage of electrical charges; used to convert optical images to television signals. In an iconoscope the luminous flux from the object passes through an optical system and is incident on a light-sensitive target, which is a mica plate with a mosiac consisting of several million photocathodes that are insulated from one another and consist of silver grains covered with cesium or cesium oxide. The luminous flux generates a charge distribution (the so-called charge pattern) on the surface of the target. A metallic layer, the so-called signal plate, is deposited on the other side of the target. Each photocathode functions with the signal plate as a capacitor. An electron beam sweeps the mosaic of the target in a predetermined sequence, which is determined by the nature of the television scan, and discharges each capacitor through a resistor Ri (load resistor), which is usually connected to a broad-band amplifier of electric signals.
The iconoscope was proposed in 1931 by the Soviet scientist S. I. Kataev and independently by the American scientist V. K. Zworykin, who built the device in 1932. It was the first device that was capable of transmitting live programs and television films at illumination intensities exceeding 7,000–10,000 lux. During the 1950’s the iconoscope was replaced by more advanced television camera tubes, such as the supericonoscope.
REFERENCEVlasov, V. F. Elektronnye i ionnye pribory, 3rd ed. Moscow, 1960.
V. I. BARANOV