Abstract: A method of manufacturing an X-ray tube comprises the steps of applying the bearing portions with liquid metal lubricant and heating the bearing portions defined by a rotary structure and a stationary shaft to a temperature of 200.degree. C. or more in a vacuum condition. An apparatus for manufacturing an X-ray tube comprises a vacuum bell jar having a heating unit, a metal lubricant injector provided in the vacuum bell jar and a holding and controlling device for holding the rotary structure and the stationary shaft and controlling the movement and the mutual connection of the rotary structure and stationary shaft externally of the vacuum envelope.

Abstract: An X-ray apparatus is provided with an operation process in which an AC voltage is applied from a power source to a magnetic stator coil so that the components of bearings are heated by magnetic induction to melt a metal lubricant in the bearings. Thus, the lubricant can be efficiently melted before starting rotation without additionally using extra components in an X-ray tube, so that the apparatus can enjoy stable operation.

Abstract: A rotary-anode X-ray tube having a rotor, a stationary shaft, and a sliding bearing connecting the rotor and the stationary shaft, forming a gap filled with liquid metal lubricant. The rotor has a first rotary member supporting an anode target and a second rotary member at which a sliding bearing is installed and which is coaxial with the first rotary member. The first and the second rotary members are connected at that end of the heat conductive path which is remote from the anode target. A heat insulating gap is formed at all fitting portions, but the remote end. Therefore, the temperature rise of the sliding bearing is controlled without using refregerant, and stable rotation of the bearing is secured.

Abstract: A rotary X-ray tube of the anode type wherein a jacket which serves to prevent lubricant from being scattered into the space in a vacuum envelope is attached to at least one of a rotary structure to which an anode target is fixed and a stationary structure for holding the rotating body, enclosing a clearance opening which forms a border relative to the space in the vacuum envelope.

Abstract: A rotary X-ray tube of the anode type wherein at least one of bearing surfaces which are partly formed on rotary and stationary structures is made of ceramics whose main component is the nitride, boride or carbide of at least one of those deviation metals, except chromium, which belong to a group IVA, VA or VIA element of a period 4, 5 or 6 of the Periodic Table.

Abstract: In a rotary-anode type X-ray tube, a rotary-anode is fixed to a cylindrical rotary structure, and a columnar stationary shaft is fitted in the rotary structure. A gap is formed between the rotary structure and the stationary shaft. The gap is filled with a liquid metal lubricant. Spiral grooves are formed in part of the outer surface of the stationary shaft to form a radial sliding bearing between the stationary shaft and the rotary structure. Spiral grooves are formed in the end faces of the stationary shaft to form a thrust sliding bearing between the stationary shaft and the rotary structure. A recess is formed in the stationary shaft to communicate with gaps in the radial sliding bearing. A lubricant storage chamber for storing the liquid metal lubricant is formed in the stationary shaft along the center axis. The storage chamber communicates with communicating holes which radially extend to be open to an outer surface region, of the stationary shaft, in which no spiral grooves are formed.

Abstract: A rotary-anode type X-ray tube wherein bubbles produced in the gap of a sliding bearing are securely and easily replaced with liquid metal lubricant, and the metal lubricant is prevented from leaking. The rotary anode is secured to a cylindrical rotary structure. A columnar fixed structure is secured to the rotary structure forming a gap between the rotary structure and fixed structure. A liquid metal lubricant fills the gap. Spiral grooves are formed on a part of the outer surface of the fixed structure and the sliding bearing is installed between the fixed structure and the rotary structure. The rotary structure and fixed structure are housed in a vacuum envelope. The gap of the sliding bearing is connected to the space inside the vacuum envelope through an annular space. A gap is formed between a ring block for blocking the opening of the rotary structure and the fixed structure.

Abstract: In a rotary-anode type X-ray tube, a rotary anode is fixed to a cylindrical rotary structure, and a columnar stationary shaft is fit in the rotary structure. A gap is formed between the rotary structure and the stationary shaft, and the gap is filled with a liquid metal lubricant. Spiral grooves are formed in portions of the outer surface of the stationary shaft to form a sliding bearing between the stationary shaft and the rotary structure. Base members of molybdenum, tungsten, niobium, or tantalum, as surface portions, are formed on the inner surface of the rotary structure and the outer surface of the stationary shaft, and reaction layers containing the material for the base member and gallium are respectively formed on the surface portions to a thickness of 1 .mu.m or more.

Abstract: A method for manufacturing a color CRT includes the step of coating a shadow mask of the color CRT in black. It further includes the step of forming an electron beam reflecting film by depositing tungsten oxide with a large electron beam reflection coefficient on the side of an electron beam irradiated surface of the shadow mask coated in black.

Abstract: An X-ray image intensifier has an input phosphor screen with a substrate in which a large number of small holes are formed, and a fluorescent material filled in the small holes. A ratio of a maximum inner diameter to a depth of each small hole is set to be 0.5 or less. Alternatively, the input phosphor screen of the X-ray image intensifier of the invention includes a substrate in which a large number of small holes are formed, a low-refractive-index material layer formed on the inner wall of each small hole, and a fluorescent material having a refractive index higher than the low-refractive-index material layer filling each small hole.

Abstract: An X-ray image intensifier has an input phosphor screen with a substrate in which a large number of small holes are formed, and a fluorescent material filled in the small holes. A ratio of a maximum inner diameter to a depth of each small hole is set to be 0.5 or less. Alternatively, the input phosphor screen of the X-ray image intensifier of the invention includes a substrate in which a large number of small holes are formed, a low-refractive-index material layer formed on the inner wall of each small hole, and a fluorescent material having a refractive index higher than the low-refractive-index material layer filling in each small hole.

Abstract: An X-ray image intensifier includes an input screen for converting incident X-ray into photoelectrons. The input screen has a substrate, a phosphor layer having a layer number of columnar crystals of a phosphor formed with gaps therebetween on the substrate, and a photoelectric layer directly or indirectly provided on the phosphor layer. The columnar crystals at a peripheral edge portion of the input screen are thinner than the columnar crystals at a central portion of the input screen.

Abstract: An X-ray image intensifier includes an input screen for converting incident X-rays into photoelectrons, and an output screen for converting the photoelectrons into visible light. The input screen includes a phosphor layer. The phosphor layer has a large number of columnar crystals of a phosphor which have end faces constituting a smooth surface facing the output screen. A low-refractive-index layer is formed on the phosphor layer and made of a material having a refractive index smaller than a refractive index of the phosphor, with respect to the light having a specified wavelength, at which the fluorescence of the phosphor is the most intensive. A photoemissive layer is formed directly or indirectly on the low-refractive-index layer.

Abstract: An X-ray image intensifier comprising a vacuum envelope and an input screen having an improved sensitivity and including a substrate disposed on the X-ray input side of the vacuum envelope, a phosphor layer formed on the substrate and a photocathode formed on the phosphor layer. The phosphor layer consists of columnar crystals extending in a direction perpendicular to the substrate surface. The tip portions of the columnar crystals are deformed to close the upper portion of the clearances formed between the columnar crystals.

Abstract: An X-ray fluorescent image intensifier is disclosed, which comprises an input screen for converting an incident X-ray image into photoelectrons, electrodes for accelerating and focusing photoelectrons and an output screen for converting the accelerated and focused photoelectrons. The input screen consists of an input substrate consisting of a lamination of a plurality of mesh plates each having a plurality of apertures, said input substrate having a plurality of through holes consisting of an interconnection of said apertures, and phosphor buried in said through holes, and a photocathode formed on said input substrate with phosphor buried in said through holes.

Abstract: An X-ray tube has a cathode assembly for emitting an electron beam and an anode target facing this assembly in an evacuated envelope. The anode target defines a target surface that is slightly inclined to the electron beam axis and the direction in which it is inclined coincides with an X-ray irradiation direction. The cathode assembly comprises a flat cathode with a flat electron emission surface and a focussing electrode which focuses electrons emitted by the cathode. The cathode's electron emission surface is elongated and its long axis is coincident with the direction of X-ray irradiation. The focussing electrode possesses an axially symmetric opening with generally the same dimensions lengthways and crosswise.

Abstract: An X-ray image intensifier includes an input screen. The input screen has a base plate, a phosphor layer formed on the base plate, a transparent conductive film formed on the phosphor layer, and a photoemissive layer formed on the conductive film. The conductive film has a crystallinity wherein an average crystal size along a direction parallel to a surface of the conductive film is 500 .ANG. or more.

Abstract: An X-ray imaging apparatus comprising an X-ray generator having a cylindrical rotating target, a slit plate having a slit extending in a direction perpendicular to the direction in which an X-ray focal point moves on the target, the slit plate and rotating target being moved relatively in a direction perpendicular to the direction in which the slit extends, an X-ray detector arranged opposite to the slit plate with an object interposed between them and serving to convert X-ray beams passing through the slit and the object to electrical signals, a signal processor for picking up only those signals which relate to the object from these electrical signals obtained through the X-ray detector, and a display device for displaying an X-ray image which corresponds to the signals picked up by the signal processor.

Abstract: An X-ray tube apparatus is disclosed, which comprises a vacuum envelope and, an anode target and a cathode assembly both disposed in the envelope and facing each other. The cathode assembly includes a filament for emitting an electron beam, filament supports for supporting the filament and a beam shaping electrode for passing through the electron beam from the filament and focusing the electron beam. The filament has a flat sheet-like electron emission portion, a pair of U-shaped portions provided at the opposite ends of the electron emission portion, in such manner that they extend from the opposite ends in the direction away from the anode target and bend back toward the anode target, and a pair of supported end portions each extending from the U-shaped portions.

Abstract: A ceramic center for a machine tool, having at its one end a bearing portion for supporting a workpiece at its one end on the axis of rotation. The ceramic center is formed of a sintered ceramic mass having a rupture toughness of at least 3.5 MN/m.sup.3/2 at a room temperature, and a density of at least 90% of the theoretical value.