Abstract: The photocathode according to this invention is characterized in that an aluminium thin film is formed on a substrate, and then an antimony thin layer is deposited directly on the aluminium thin film and is activated by an alkali metal. It is especially preferable that the antimony thin layer is deposited in a thickness of 15 .mu.g/cm.sup.2 to 45 .mu.g/cm.sup.2 and is activated by an alkali metal. Such reflection-type photocathode is applicable to photomultipliers. Among functions which are considered to be done by the Al film. which is in direct contact with the Sb layer, a first one is to prevent the alloying between the Sb layer and the substrate (e.g., Ni), and a second one is to augment a reflectance of light to be detected.

Abstract: A proximity image intensifier for use in a light amplifier in a high-sensitivity hand-held camera for broadcasting service or the like, which includes a photocathode for photoelectrically converting an optical image, a phosphor screen for receiving photoelectrons from the photocathode and producing an intensified optical image, and a high-voltage power supply for applying a high voltage across the photocathode and the phosphor screen. For protecting the phosphor screen from burnout due to a spot of incident light, a resistor is interposed in a power supply path at a position immediately before at least one of the photocathode and the phosphor screen to reduce an electrostatic capacitance between the photocathode and the phosphor screen.

Abstract: An image intensifier tube and a solid-state image pickup device are combined to form a unified image pickup device. A thin fiber plate with thickness of 0.5-1.5 mm is interposed between a phosphor layer of the image intensifier tube and a photosensitive layer of the solid-state image pickup device. A microchannel plate may be incorporated to multiply photoelectrons emitted from a photocathode.

Abstract: An image intensifier tube and a solid-state image pickup device are combined to form a unified image pickup device. A thin transparent glass layer polished to a thickness of 50 microns or less is interposed between a phosphor layer of the image intensifier tube and a photosensitive layer of the solid-state image pickup device. A microchannel plate may be incorporated to multiply photoelectrons emitted from a photocathode.