U.S. Philips Corporation

Jan T Gerkema

Gerrit J Koel

Frederik W Gorter

Jozef B Pelzer

Evert M Kamerbeek

Johannes L Hagen

Andries R Miedema

Theodorus C Bertens

Everhardus A Muijderman

Johan A Rietdijk

Anton K Niessen

Hendrikus Josephus Van Dijk

An X-ray tube comprising a rotary anode which is journalled in a helical-groove bearing is constructed so that the axial median plane of the rotary anode system is approximately coincident with the axial center of the helical-groove bearing. The bearing block for the anode system is connected to the tube base preferably via a connection whose rigidity is adapted to the weight, the geometry and the weight distribution of the anode system. The connection allows for cooling of the bearing block by means of a cooling liquid.

X-ray tube comprising an anode disc rotatably journalled on a

The bearing in an X-ray tube comprising a liquid metal lubricated helical-groove bearing is provided with a push-pull bearing at one or both end faces of a bearing member. Consequently, the bearing member need not be further secured so that, notably in the case of suitable cooling of the anode disc and the bearing, extremely precise positioning of the radiation object point in the tube can be achieved.

X-ray tube comprising anode disc rotatably supported by bearing having

In order to prevent the escape of metal lubricant in a helical-groove bearing, the helical-groove bearing is provided with an anti-wetting layer on the surfaces which adjoin the helically grooved surfaces and which could act as a creepage path for the metal lubricant. An extremely accurate definition of the bearing portions to be wetted by the lubricant is also obtained by means of these layers. Thus, more complex bearings can also be locally provided with a metal lubricant.

Metal-lubricated helical-groove bearing comprising an anti-wetting layer

An X-ray tube having a rotary anode which is accommodated in a vacuum-tight housing so as to be rotatable by means of at least one spirally grooved bearing. The mutually cooperating surfaces of the bearing consist essentially of Mo or of an alloy of Mo and W and are effectively wetted by a Ga-alloy serving as a bearing lubricant. In order to extend the life of the X-ray tube, 1 to 4% by weight of Ag and/or Cu are added to the Ga-alloy, as a result of which the formation of crystalline compounds is inhibited.

X-Ray tube having a rotary anode

Bearings can be lubricated with ductile metal films. It has been found that the service life of such lubricating films can be improved by the use of metals which are alloyed with a component having a higher surface tension than the metal.

Device incorporating a bearing

An X-ray tube having a rotary anode which is supported by a bearing system comprising an axial magnetic bearing and at least one radial sleeve bearing. In operation, mutually cooperating metal (e.g. W or Mo) supporting faces of the sleeve bearing are separated by a liquid layer wetting the supporting faces. The liquid layer consists of a metal or a metal alloy, such as Ga or a Ga alloy, whose vapor pressure at 300.degree. C. is below 10.sup.-5 N/m.sup.2, and which does not attack the supporting faces to any substantial extent. The tube has a long life, produces little noise during operation, and is of relatively simple construction.

Rotary anode X-ray tube

A thin-film magnetic head for writing information in and reading information from a track of a magnetic recording medium in which the head comprises a magnetically permeable yoke having two limbs between which a writing/reading gap is formed. In a construction in which the limbs of the yoke overlap each other at the area of the writing/reading gap, they are bridged by a magneto-resistive reading element at a location remote from the reading/writing gap. A conductor is provided in some forms of the invention which extends intermediate the laterally overlapping limbs. This conductor is utilized for producing a writing flux in the magnetic yoke. Another conductor may be provided which extends through a window or opening in the yoke, which is remote from the reading/writing gap. This other conductor is utilized during writing operation to maximize efficiency.

Thin-film magnetic head for reading and writing information

A rotary-anode X-ray tube, comprising a rotary anode which is journalled in a vacuum-tight housing by means of at least one sleeve bearing whose mutually co-operating bearing surfaces are made of W or Mo or of an alloy of W and Mo. The bearing is lubricated by Ga or a Ga alloy having a melting point below 25.degree. C. The Ga or Ga alloy lubricant is in molecular wetting contact with the bearing surfaces so that the bearing surfaces are completely separated from each other in the loaded condition. During standstill, as well as during rotation, the lubricant is not forced out of the bearing, so that the bearing surfaces cannot become fused. The wear and the bearing noise are therefore extremely low. The desired, thorough wetting is obtained by making the bearing surfaces, as well as the Ga alloy, oxide-free before they are brought into contact with each other.

Rotary-anode X-ray tube

A method of manufacturing a device in which a conductive base pattern is formed on a substrate and is reinforced by electroplating so as to obtain a conductor pattern, characterized in that at least a surface layer of the substrate consists of an electrically insulating material on which an auxiliary layer is provided having a sheet resistance between 10.sup.12 and 10.sup.17 ohms per square, after which the base pattern is formed on the last-mentioned layer.

Method of reinforcing a conductive base pattern by electroplating and

A magnetic head for use in a magnetic reproduction device has a substrate in which a groove is provided. Provided on one wall of the groove is a magnetic field-sensitive element which is preferably positioned normal to an associated recording medium for coupling to the magnetic head.

Magnetic head using a magnetic field-sensitive element and method of

A thin-film magnetic head for writing information in and reading information from a track of a magnetic recording medium in which the head comprises a magnetically permeable yoke having two limbs between which a writing/reading gap is formed. In a construction in which the limbs of the yoke are opposite to each other, one limb is interrupted by a gap which is bridged by a magneto-resistive reading element.

A thin-film magnetic head for writing information in and reading information from a track of a magnetic recording medium in which the head comprises a magnetically permeable yoke having two limbs between which a writing and reading gap is formed. In a construction in which the limbs of the yoke are opposite to each other, one limb is interrupted by a gap which is bridged by a magneto-resistive reading element. In a construction in which the limbs of the yoke overlap each other at the area of the writing/reading gap, they are bridged by a magneto-resistive reading element in another place.

A thin-film magnetic head having improved playback properties in which the gap-bounding core parts overlap each other laterally while enclosing a layer having a gap and in which a first core part has the shape of a closed loop and is bridged in the center by a second core part. The parts of the first core part on either side of the bridge are provided with identical coils, while the first core part at the area of the overlap is divided centrally by an extra gap. Upon playing back, the difference signals of the coils then provides an indication as regards the position relative to the track.

Thin film magnetic head with a gap formed between a loop shaped core

The invention relates to a method of manufacturing a device, for example, a magnetic head for recording and playing back information on a magnetisable medium. In this method, a substrate of semiconductor material is profiled by a selective electrolytic etching process. Preceding the etching process, the part of the substrate to be removed by said process is formed by a local doping treatment, for example, by diffusion. The doping treatment may be carried out in several overlapping steps.

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Eindhoven, Netherlands

Jan T Gerkema