Abstract: An apparatus for measuring a curvature of a surface (1), comprising means for irradiating a first light beam (S1), a second light beam (S2) and a third light beam (S3) onto a surface (1) of a sample (12), a detector (5) comprising at least one detector plane and being adapted to detect a first position of the reflected first light beam (S1), a second position of the reflected second light beam (S2) and a third position of the reflected third light beam (S3) in the at least one detector plane, means for determining a first distance between the first position of the first light beam (S1) and the third position of the third light beam (S3) and a second distance between the second position of the second light beam (S2) and the third position of the third light beam (S3), and means for determining a mean curvature of the surface from the first distance and the second distance.

Abstract: A pyrometer that is adapted for detecting radiation in the range of 250 to 450 nm is disclosed. The pyrometer can be used for determining the temperature of a matter thermally emitting only ultraviolet-radiation. In particular, the pyrometer can include: a detector having an active area adapted for measuring thermal radiation, a longpass filter having a cut-off wavelength in the range of 400 to 450 nm, means adapted for alternately activating and deactivating the longpass filter, means adapted for measuring a first thermal radiation signal when the longpass filter is deactivated and adapted for measuring a second thermal radiation signal when the longpass filter is activated, and means adapted for determining a temperature corresponding to the measured thermal radiation from a difference of the first radiation signal and the second radiation signal.

Abstract: The present invention relates to a method for calibrating a pyrometer, a method for determining the temperature of a semiconducting wafer and a system for determining the temperature of a semiconducting wafer. It is an object of the present invention to provide a method for calibrating a pyrometer which overcomes the disadvantages of the prior art.

Abstract: The present invention relates to a method and an apparatus for determining the layer thickness and the refractive index of a sample. It is an object of the present invention to provide a method for determining the layer thickness of a sample (layer) having high light scattering characteristics that allows a fast (real-time process) and cost-effective measurement having a high accuracy.

Abstract: The invention relates to a device and a method for the measurement of the curvature of a surface (1), which is more exact and less expensive than prior art devices. The device comprises a light source (2) for the irradiation of a light beam (3) onto the surface (1), in which a birefingent element (4) is arranged between light source (2) and surface (1), in which furthermore a detector (5) is arranged for the detection of the partial beams (6,7), that are reflected from the surface (1), and at least one main axis (17) of the birefringent element (4) is positioned with respect to the light beam (3) of the light source (2) in such a way, that the light beam (3) of the light source (2) is split up into at least two parallel beams (6,7).