Abstract: A high-pressure discharge lamp which includes a light-transmitting air-tight discharge container, an electrode formed of tungsten as a main component and fixedly sealed in the discharge container, and a discharge medium containing a halide of a light emitting metal and sealed in the discharge container. The surface of the electrode is defined as follows. That is, the average value of center line average roughness Ra of the surface, is set to 0.3 &mgr;m or less, or the average value of the center line average roughness Rz of the surface of the electrode, is set to 1.0 &mgr;m or less, or the average value of the surface area increasing rate of the surface of the electrode is set to 1.0% or less.

Abstract: A high-pressure discharge lamp which includes a light-transmitting air-tight discharge container, an electrode formed of tungsten as a main component and fixedly sealed in the discharge container, and a discharge medium containing a halide of a light emitting metal and sealed in the discharge container. The surface of the electrode is defined as follows. That is, the average value of center line average roughness Ra of the surface, is set to 0.3 &mgr;m or less, or the average value of the center line average roughness Rz of the surface of the electrode, is set to 1.0 &mgr;m or less, or the average value of the surface area increasing rate of the surface of the electrode is set to 1.0% or less.

Abstract: An X-ray image intensifier that includes a vacuum envelope having a metal X-ray input window and an input screen formed on the inner surface of the X-ray input window, a focusing electrode, an anode, and an output screen arranged in the vacuum envelope along the traveling direction of electrons generated from the input screen. The X-ray input window has a rough, surface-hardened layer on the side on which the input screen is formed. The input screen includes a phosphor layer adjacent to the rough, surface-hardened layer and a photocathode formed on the phosphor layer.

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: An image intensifying tube, such as a image intensifying tube which converts X-rays into a visible image, comprises a curved input screen which comprises a substrate that receives input radiation and a photocathode supported on the substrate, and an output screen which converts the electrons emitted by the photocathode into a visible image. In order to compensate for changes in luminosity due to the curvature of the input screen, an intermediary layer of radially variable thickness is deposited between the substrate and the photocathode. The intermediary layer is made from a material, such as indium oxide (In.sub.2 O.sub.3), which modifies the electron emitting characteristics of the photocathode as a function of the thickness the intermediary layer. Thus, a thicker intermediary layer near the center of the input screen will compensate for reduced luminosity at the edges of the screen.