Abstract: A bearing for use in a vacuum chamber comprises a gas bearing discharging pressurised gas into a gap between two members to maintain a predetermined separation between those members.

Abstract: A long-stroke movement is fed-through into a vacuum chamber by providing a sliding seal over an aperture in the vacuum chamber wall. The object to be moved, which may be a mask or wafer table in a lithographic apparatus, within the vacuum chamber is connected to or mounted on the sliding seal and moved by movement of the sliding seal. The sliding seal may be a plate, a bowl or a labyrinth of interleaved plates.

Abstract: A reference frame provided in a vacuum chamber is supported by support pillars extending through and isolated from the vacuum chamber walls to isolate the reference frame from vibrations in the vacuum chamber. The gap between the support pillar and the vacuum chamber wall may be sealed by a low-stiffness seal. The low stiffness seal may be a three part seal allowing relative motion in six-degrees of freedom.

Abstract: A bearing for use in a vacuum chamber comprises a gas bearing discharging pressurised gas into a gap between two members to maintain a predetermined separation between those members.

Abstract: An object table is supported in a vacuum chamber by an elongate beam or beams extending through elongate slots in opposite walls of the vacuum chamber. Displacement of the beam in two orthogonal directions is achieved by displacing the beam laterally and longitudinally. The elongate slots are sealed by sliding plates supported by a gas bearing. The beam is driven longitudinally by linear motors acting against between a balance mass and the beam. The beam is driven laterally by linear motors acting between a balance mass and the sliding plates. The two balance masses may be separate or combined.

Abstract: A bearing for use in a vacuum chamber comprises a gas bearing discharging pressurised gas into a gap between two members to maintain a predetermined separation between those members. To avoid the gas forming the gas bearing being an unacceptable leak into the vacuum chamber, a vacuum pump is provided between the vacuum chamber and the gas bearing.

Abstract: A lithographic apparatus for step-and-scan operation has a three stage structure for the wafer stage. During step-and-scan operation, the long-stroke stage is moved steadily along the row or column of dies to be exposed sequentially. An intermediate scanning stage moves in a figure-of-eight motion relative to the long-stroke stage so that the net movement of the fine stage, which is carried by the scanning stage, is a meander path.

Abstract: In a lithographic projection apparatus, a slider is provided for motion of the substrate table or mask table. The slider is supported on a gas-bearing and separates a region at atmospheric pressure from a vacuum space region. A differential pressure pump is provided to maintain the pressure difference in the presence of the gas-bearing. A pressure compensation vessel is provided on top of the slider and also contains a vacuum. Over most of the area of the slider, the pressure on its opposed first and second sides is the same and so deformation of the slider is avoided. The sidewalls of the pressure compensation vessel transmit the external gas pressure to the slider such that they are in line with the forces of the gas-bearing.

Abstract: A long-stroke movement is fed-through into a vacuum chamber by providing a sliding seal over an aperture in the vacuum chamber wall. The object to be moved, which may be a mask or wafer table in a lithographic apparatus, within the vacuum chamber is connected to or mounted on the sliding seal and moved by movement of the sliding seal. The sliding seal may be a plate, a bowl or a labyrinth of interleaved plates.

Abstract: An object table is supported in a vacuum chamber by an elongate beam or beams extending though elongate slots in opposite walls of the vacuum chamber. Displacement of the beam in two orthogonal directions is achieved by displacing the beam laterally and longitudinally. The elongate slots are sealed by sliding plates supported by a gas bearing. The beam is driven longitudinally by linear motors acting against between a balance mass and the beam. The beam is driven laterally by linear motors acting between a balance mass and the sliding plates. The two balance masses may be separate or combined.

Abstract: A long-stroke movement is fed-through into a vacuum chamber by providing a sliding seal over an aperture in the vacuum chamber wall. The object to be moved, which may be a mask or wafer table in a lithographic apparatus, within the vacuum chamber is connected to or mounted on the sliding seal and moved by movement of the sliding seal. The sliding seal may be a plate, a bowl or a labyrinth of interleaved plates.

Abstract: An object table is supported in a vacuum chamber by an elongate beam or beams extending though elongate slots in opposite walls of the vacuum chamber. Displacement of the beam in two orthogonal directions is achieved by displacing the beam laterally and longitudinally. The elongate slots are sealed by sliding plates supported by a gas bearing. The beam is driven longitudinally by linear motors acting against between a balance mass and the beam. The beam is driven laterally by linear motors acting between a balance mass and the sliding plates. The two balance masses may be separate or combined.

Abstract: A method of manufacturing a dynamic groove bearing having parts rotatable relative to one another. The bearing parts include cooperating bearing surfaces and a pattern of grooves by means of a metal-removing tool. A first bearing part is fastened to a rotatable support of a machine tool, which is rotated in a constant direction. The tool is periodically displaced relative to the first bearing part parallel to a direction transverse to the bearing surface of the first bearing part by a positioning device with a frequency which is determined by a product of a rotation frequency of the support and a number of grooves on the bearing surface of the first bearing part. The tool is periodically displaced in a sinusoidal movement and the positioning device may include a piezoelectric actuator (95). A data storage unit including dynamic groove bearings is also provided.

Abstract: A flat display device is provided with a wire cathode or wire cathodes and with apertures which allow passage of electrons emitted by the wire cathode. The wire cathode is stretched in a wire-cathode support having positioning grooves for the wire cathode. This support engages the element in which the passages are made. The support and the element are provided with corresponding contacting surfaces.

Abstract: The invention relates to an optoelectronic device comprising a semiconductor laser enclosed in an envelope, an optical fibre coupled to the semiconductor laser, and further coupled to at least one optical isolator and an outgoing optical fibre (pigtail). According to the invention, the semiconductor laser and the optical isolator are each enclosed in a separate module. The laser module mainly provides space to the semiconductor laser and to an optical fibre coupled thereto and ending in a ferrule in a tubular projection of the laser module. The module for the optical isolator is tubular in shape and contains in that order a first graded index lens, an optical isolator, a second graded index lens, and an outgoing optical fibre (pigtail) coupled to this second graded index lens through a ferrule.

Abstract: An apparatus is described for accurately measuring the profile on an object. The apparatus comprises two probes for simultaneously scanning the object to be measured and the reference object, the objects being rotatable about the same axis. Each of the probes is provided with a reflecting element, which are respectively incorporated in the measuring arm and reference arm of an interferometer.