Abstract: In a method and apparatus for measuring a property of a transparent tubular object, a laser beam scans the object, and laser light originating from the object is detected in a first detection direction parallel to the laser beam direction, or in the first and in a second detection direction at an angle thereto, in particular at 90°. The inner radius of the object may be calculated from the refractive index, scanning speed, outer diameter detected in the first detection direction, and, in the second detection direction, the time difference between laser light reflected from the outer surface of the object and laser light refracted into the object and reflected at the inner surface thereof. If the time of detecting laser light refracted into the object and reflected at the inner surface thereof in the first detection direction is known, the refractive index is not required.

Abstract: In a method and apparatus for measuring a property of a transparent tubular object, a laser beam scans the object, and laser light originating from the object is detected in a first detection direction parallel to the laser beam direction, or in the first and in a second detection direction at an angle thereto, in particular at 90°. The inner radius of the object may be calculated from the refractive index, scanning speed, outer diameter detected in the first detection direction, and, in the second detection direction, the time difference between laser light reflected from the outer surface of the object and laser light refracted into the object and reflected at the inner surface thereof. If the time of detecting laser light refracted into the object and reflected at the inner surface thereof in the first detection direction is known, the refractive index is not required.

Abstract: The present invention provides an interference measuring device with an optical system that can receive light reflected from a measurement object of a surface profile that is not perpendicular to an optical axis. An interference measuring device includes a light source for emitting light and an interferometric objective lens. The interferometric objective lens includes a reference mirror disposed in a reference beam path and a beam splitter that splits the incident light into a beam traveling along the reference beam path and a beam traveling along a measurement beam path. The beam splitter also combines the beam reflected off the reference mirror with the beam reflected off a measurement object disposed in the measurement beam path before emitting the combined beams.

Abstract: An interferometer system to generate an interference signal of a surface of a sample includes a broadband illuminator to provide a broadband illumination beam, a beam splitter to split the broadband illumination beam in a reference beam for reflection on a reference reflector and a measurement beam for reflection on the surface of the sample, and a detector to receive an interference radiation intensity created between the reference beam reflected from the reference reflector and the reflected measurement beam from the surface of the sample to generate an interference signal. The interferometer system having a continuous variable broadband reflector in the beam splitter and/or the reference reflector to adjust the broadband radiation intensity balance between the measurement beam and the reference beam.

Abstract: The present invention provides an interference measuring device with an optical system that can receive light reflected from a measurement object of a surface profile that is not perpendicular to an optical axis. An interference measuring device includes a light source for emitting light and an interferometric objective lens. The interferometric objective lens includes a reference mirror disposed in a reference beam path and a beam splitter that splits the incident light into a beam traveling along the reference beam path and a beam traveling along a measurement beam path. The beam splitter also combines the beam reflected off the reference mirror with the beam reflected off a measurement object disposed in the measurement beam path before emitting the combined beams.

Abstract: In a method and apparatus for determining the height of a plurality of spatial positions on a surface of a specimen, a light beam is projected on the surface. The surface is scanned along an optical axis in different scanning positions. The light reflected by the surface is detected in scanning positions with a spatial pattern having corresponding spatial pattern positions. From the detected light for each spatial position of the surface, an envelope curve of intensity values corresponding to scanning positions is determined. A maximum of the envelope curve and its corresponding scanning position being representative of the height of the spatial position of the surface is selected. The spatial pattern is moved in a sequence of 2n steps (n>2) in a first and a second spatial direction over a distance of ¼ and 1/n pattern wavelength, respectively.

Abstract: Method of determining a property of a sample from a correlogram obtainable by scanning of a surface of the sample through a focal plane of an objective using broad-band interferometry is provided. The correlogram may be displaying interference radiation intensity as a function of the scanning distance from the surface. The correlogram may be correlated with a secondary correlogram to obtain a cross correlogram or with the same correlogram to obtain an autocorrelogram. A property of the sample may be determined from the auto or cross correlogram.

Abstract: In a method and apparatus for determining the height of a plurality of spatial positions on a surface of a specimen, a light beam is projected on the surface. The light beam has a sinusoidal spatial pattern in at least two directions perpendicular to an optical axis of the light beam, and which is moved to different spatial pattern positions. The surface is scanned along the optical axis in different scanning positions. A fixed relationship between a moving distance between subsequent spatial pattern positions, and a scanning distance between subsequent scanning positions exists. The light reflected by the surface is detected in scanning positions with the spatial pattern having corresponding spatial pattern positions. From the detected light for each spatial position of the surface, an envelope curve of intensity values corresponding to scanning positions is determined.

Abstract: An interferometer system to generate an interference signal of a surface of a sample includes a broadband illuminator to provide a broadband illumination beam, a beam splitter to split the broadband illumination beam in a reference beam for reflection on a reference reflector and a measurement beam for reflection on the surface of the sample, and a detector to receive an interference radiation intensity created between the reference beam reflected from the reference reflector and the reflected measurement beam from the surface of the sample to generate an interference signal. The interferometer system having a continuous variable broadband reflector in the beam splitter and/or the reference reflector to adjust the broadband radiation intensity balance between the measurement beam and the reference beam.

Abstract: Method of determining a property of a sample from a correlogram obtainable by scanning of a surface of the sample through a focal plane of an objective using broad-band interferometry is provided. The correlogram may be displaying interference radiation intensity as a function of the scanning distance from the surface. The correlogram may be correlated with a secondary correlogram to obtain a cross correlogram or with the same correlogram to obtain an autocorrelogram. A property of the sample may be determined from the auto or cross correlogram.