Abstract: An X-ray imaging tube comprising an vacuum envelope, and input screen located in the input end of the envelope, an output screen located in the output end of the envelope, an anode located in the output end of the envelope, and a plurality of beam-converging electrodes located in the envelope and arranged along the inner surface of the envelope. The tube has an magnification of used input field size of 2.3 or more. The components of the tube have such positions and sizes, thus satisfying the following relations:3.5.ltoreq.G3.sub.D /A.sub.D .ltoreq.5.0-3.65.times.MAG+1.00.ltoreq.G3.sub.L /L.ltoreq.-3.65.times.MAG+1.05where L is the distance between the input and output screens, A.sub.D is the inside diameter of the anode or one of the beam-converging electrodes set at the same potential as the anode, which is closer to the input screen than any other beam-converging electrodes set at the same potential as the anode, G3.sub.

Abstract: An X-ray television apparatus includes an X-ray image intensifier and an imaging unit. The X-ray image intensifier converts an X-ray image into a visible image. The visible image is transmitted to the imaging unit by optical fiber bundles coupled with each other by a coupling mechanism. The imaging unit converts the visible image into an electrical signal of an image. Bolts are threadably engaged with a flat ring base provided to the X-ray image intensifier. By an elastic pressure of coil springs into which the bolts are inserted, a holding member provided to the coupling mechanism couples the imaging tube to the X-ray image intensifier via the optical fiber bundles. An electrostatic shielding film is formed on a surface of the holding member and prevents a pseudo signal generated by the X-ray image intensifier from entering the imaging unit, thereby reducing the noise components contained in the electrical signal of an image.

Abstract: An X-ray image intensifier includes an input surface and an output surface facing the input surface. The input surface has a base and a phosphor layer formed on the base and having a predetermined effective radius. The phosphor layer includes a thickest portion which has a thickness about 105 to 115% of a thickness of a center of the layer and is located in a region spaced from the center toward the periphery of the layer by a distance about 60 to 80% of the effective radius. The phosphor layer is formed so that the thickness is gradually increased from the center to the thickest portion and a region between the thickest portion and the periphery of the layer has a thickness about 50 to 100% of the thickness of the thickest portion.

Abstract: A phosphor screen constructed by forming a phosphor layer on one side of an optical fiber plate consisting of a large number of bundled single optical fibers, each of which fibers comprises a cylindrical core and a clad surrounding the curved surface of the fiber core. At least that side of the respective fiber cores which faces the phosphor layer is removed, to provide a depression. Sufficiently large spaces are formed between the fiber cores and phosphor layer, to prevent both members from being brought into optical contact with each other.

Abstract: A phosphor screen which has an optical fiber plate formed of a number of bundled single optical fibers, each of which fibers consists essentially of a cylindrical core and a clad surrounding the curved peripheral wall of the core and a phosphor layer formed on one surface of the optical fiber plate, characterized in that the cylindrical core on the other surface of the optical fiber plate is removed, to provide a depression of a depth of at least 1 .mu.m, thereby producing an image having high contrast.

Abstract: A phosphor screen constructed by forming a phosphor layer on one side of an optical fiber plate consisting of a large number of bundled single optical fibers, each of which fibers comprises a cylindrical core and a clad surrounding the curved surface of the fiber core. At least that side of the respective fiber cores which faces the phosphor layer is removed, to provide a depression. Sufficiently large spaces are formed between the fiber cores and phosphor layer, to prevent both members from being brought into optical contact with each other.

Abstract: A phosphor screen which has an optical fiber plate formed of a number of bundled single optical fibers, each of which fibers consists essentially of a cylindrical core and a clad surrounding the curved peripheral wall of the core and a phosphor layer formed on one surface of the optical fiber plate, characterized in that the cylindrical core on the other surface of the optical fiber plate is removed, to provide a depression of a depth of at least 1 .mu.m, thereby producing an image having high contrast.