Abstract: This image tube converts irradiated electrons into fluorescence by irradiating electrons converted from a light beam by a photocathode onto a YAG crystal member. Since the YAG crystal member is a single unitary solid, the fluorescence generated on the input surface of the YAG crystal member contains no fixed pattern noise.

Abstract: This invention relates to an improvement of a reflection mode alkali photocathode which relies on controlling a deposition weight of antimony. The reflection mode alkali photocathode according to this invention includes a thin layer of antimony directly deposited on a base substrate and activated by alkali metals. The thin film of antimony is deposited in a thickness of below 100 .mu.g/cm.sup.2. This reflection mode photocathode is suitably usable in photomultipliers. As the base substrate, nickel, aluminium and stainless, etc. are used. As the alkali metals, cesium, potassium, sodium and rubidium are usable.

Abstract: This invention relates to an improvement of a reflection mode alkali photocathode which relies on controlling a deposition weight of antimony. The reflection mode alkali photocathode according to this invention includes a thin layer of antimony directly deposited on a base substrate and activated by alkali metals. The thin film of antimony is deposited in a thickness of below 100 .mu.g/cm.sup.2. This reflection mode photocathode is suitably usable in photomultipliers. As the base substrate, nickel, aluminium and stainless, etc. are used. As the alkali metals, cesium, potassium, sodium and rubidium are usable.

Abstract: There is provided a photomultiplier in which a transmittance of an incident light and a photosensitivity is high and a hysteresis characteristic is excellent. Therefore, in the present invention, a photocathode 16, dynodes 17a to 17c and an anode 18 are supported between insulating material substrates 12a and 12b provided in a glass bulb 11. A transparent conductive film 19 is formed on an inside wall surface of a light entrance portion 15. The transparent conductive film 19 electrically contacts with a pad 20 which is led through a terminal 14 to the outside. The same potential as the photocathode 12 is applied through the pad 20 to the transparent conductive film 19. The incident light directly impinges on the photocathode 16 through the glass bulb 11 and the transparent conductive film 19 at a place corresponding to the light entrance portion 15. As a result, the incident light reaches the photocathode 12 with not being interfered at all, and the transmittance of the incident light is improved.

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 cathode for photoelectric emission or a cathode for secondary electron emission comprises a thin film made of a material which emits photoelectrons by an incident light or emits secondary electrons by an electron input on a base substrate. The average particle size of the particles forming the thin film is 200 nm to 2000 nm. It is preferred that the average particle size is nearly equal to an average diffusion length of the particle of an excited electron. Further, the average particle size is preferably larger than the mean value of penetration lengths of inputted electrons or incident lights in the particles. Moreover, preferably convexities and/or concavities formed of particles each having the average particle size are formed over the surface of a plane for the incident light or electron input. Further, it is preferred that the thin film is activated by an alkali metal and is made of compounds of at least one kind of alkali metal and an antimony metal.

Abstract: There is disclosed a phototube comprising a closed container having a light permeable face plate the outside surface of which is a light incident surface, a photocathode so provided in the closed container that at least a part of a photo-electric surface is inclined to the light incident surface, and an anode so provided in the closed container that an electron capturing surface is opposed to the photo-electric surface in parallelism therewith.

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.