Abstract: The invention relates to a method and an apparatus for determining the height of a number of spatial positions on the sample, defining a height map of a surface through interferometry with a broadband light source. The method can involve for each spatial position: obtaining a correlogram during scanning of the surface plane of the objective and estimating the point of the correlogram where an amplitude of the correlogram is at its maximum, thus determining an approximation of the height of the spatial position on the sample. The estimation of the value where the correlogram has its maximum can involve subjecting the correlogram to a Fourier transform, subjecting the Fourier transformed signal to a filter, subjecting the filtered signal to an inverse Fourier transform, and calculating the location of the center of mass of the inversed filtered Fourier transformed signal.

Abstract: The invention relates to an apparatus and a method for determining a height map of a surface of an object. The apparatus can include positioning means for the object, a light source, an optical detector for converting the received light into electrical signals, first optics for directing light from the light source to the surface and for directing the light from the surface to the optical detector, a beam splitter located between the first optics and the surface, a reference mirror, second optics located between the beam splitter an the mirror for directing the light from the beam splitter to the mirror and from the mirror to the beam splitter, scanning means, processing means that converts the signal from the optical detector into a height map. The beam splitter can be a polarizing beam splitter. A controllable polarization controller can be located between the light source and the first optics.

Abstract: An interferometric displacement measuring system operable to measure displacements of a movable object of the lithographic apparatus in a first direction using a measurement beam of radiation and a reflector. The reflector being substantially planar and substantially perpendicular to the first direction. Calibration is obtained using a first set of measurements of the angular position movable object. A phase offset in the measurement beam is affected. A second set of measurements of the angular position of the movable object is obtained. The interferometric displacement measuring system is calibrated based on the first and second sets of measurements.

Abstract: The invention relates to a method and an apparatus for determining a height of a number of spatial positions on a sample, defining a height map of a surface of said sample. The method can involve irradiating the surface of the sample with light including a spatial periodic pattern in a direction perpendicular to an optical axis and moving parallel to the pattern, scanning the surface in the direction of the optical axis for each position of the surface and detecting the light reflected by the sample by a detector during the scanning. In any scanning position, only a single image is taken, and the scanning speed has a predetermined relation to the phase of the periodic pattern. Analyzing an output signal of the detector can involve, for each spatial position of the detector, determining of an amplitude of the signal detected during the scanning and determining a scanning location where the amplitude is maximal.

Abstract: The invention relates to an apparatus and a method for determining a height map of a surface of an object. The apparatus can include positioning means for the object, a light source, an optical detector for converting the received light into electrical signals, first optics for directing light from the light source to the surface and for directing the light from the surface to the optical detector, a beam splitter located between the first optics and the surface, a reference mirror, second optics located between the beam splitter an the mirror for directing the light from the beam splitter to the mirror and from the mirror to the beam splitter, scanning means, processing means that converts the signal from the optical detector into a height map. The beam splitter can be a polarizing beam splitter. A controllable polarization controller can be located between the light source and the first optics.

Abstract: The invention relates to a method and an apparatus for determining the height of a number of spatial positions on the sample, defining a height map of a surface through interferometry with a broadband light source. The method can involve for each spatial position: obtaining a correlogram during scanning of the surface plane of the objective and estimating the point of the correlogram where an amplitude of the correlogram is at its maximum, thus determining an approximation of the height of the spatial position on the sample. The estimation of the value where the correlogram has its maximum can involve subjecting the correlogram to a Fourier transform, subjecting the Fourier transformed signal to a filter, subjecting the filtered signal to an inverse Fourier transform, and calculating the location of the centre of mass of the inversed filtered Fourier transformed signal.

Abstract: A construction for a fixed or a removable tooth replacement between two sound or restored abutment elements includes an individually cast plate made of a metal of choice (1), which is provided with an opening of defined size on the approximal side, at the level of the contact point of the abutment, and which is secured on the respective abutment by means of an etching/adhesive bonding technique. An oval adaptation piece (3), (17) with a wedge-shaped or loop-shaped engagement incision at its top, with a tapering opening at the center, and provided with a thread, is cast welded or cemented onto the plate. A movable pin (8) which is milled from metal is guided through the congruent openings of the oval adaptation piece and the plate is cemented in the small channel prepared in the abutment element (20). The pin is secured from the outside by a fastening screw (12).

Abstract: A dental drill is provided which includes a drill head carrying a drill bit and a telescopic drilling template to be attached to the drill head so that after a first hole has been drilled in the tooth with the drill bit, the template is inserted in that hole, thus insuring that a second hole parallel to the first hole is drilled with a desired spacing corresponding to that of the two pins of a dental prosthesis.

Abstract: The apparatus comprises an anchoring element (2), a pin (3) fixed thereto, and a pin (4) rotatingly and pivotingly connected thereto. By means of a plastic handle (15) detachably affixed in a groove (13) of the anchoring element, this element can easily be inserted by its pins into matching boreholes (39, 47) in the tooth (38) serving as a support for the anchoring element. The telescoping drilling template (40) can be attached to the drill head (35) of a dental drill so that after the first hole (39) has been drilled in the tooth with a drill bit (36), the template is inserted in that hole, thus ensuring that the second hole (47) is drilled with the desired spacing corresponding to that of the two pins.

Abstract: The apparatus comprises an anchoring element having a lower recess and a continuous upper recess. Pins are rotatably and swivellably mounted in the recesses. The pins comprise a cylindrical portion and a spherical portion. The anchoring element is preferably first cemented with the lower pin into a hole drilled in an existing supporting tooth, whereupon a second hole in this tooth can then be drilled through the upper continuous opening in the anchoring element for receiving the upper pin. Thus, there is no need to drill exactly spaced, parallel holes in the supporting teeth, nor is there any necessity for a drilling template.