Abstract: A method of determining a correction parameter for use in effecting alignment of a component of a metrological apparatus in at least one direction is described which includes: positioning an artefact on a support surface of a turntable of the metrological apparatus so that a measurement surface of the artefact is asymmetric with respect to a rotation axis of the turntable in the at least one direction; using a measurement probe of the measurement instrument to make a first measurement of the measurement surface; rotating the turntable; using the measurement probe of the measurement instrument to make a second measurement of the measurement surface after rotation of the turntable; and determining a correction parameter from the first and second measurements.

Abstract: A surface measurement instrument for obtaining surface characteristic data of a sample surface is described. Relative movement between a reference surface and a sample support is caused to occur while a sensor senses light intensity at intervals along a scan path to provide a series of intensity values representing interference fringes produced by a region of a sample surface during said relative movement and from which series of intensity values surface characteristic data can be derived. The sample support is both translatable and tiltable in at least one direction perpendicular to a scan direction so that the sample support can be both tilted to cause the scan path to be normal to the sample surface region and translated to compensate for translation movement due to the tilting.

Abstract: An attitude arm mounted to a support arm is rotatable about a pivot. The attitude arm holds a stylus gauge, which generates a signal representing deflection of the stylus in a measurement direction as the stylus follows a surface of a workpiece rotated on a turntable. An attitude switching mechanism allows switching between a first stylus attitude generally aligned with the turntable spindle axis and a second stylus attitude generally aligned perpendicular to the turntable spindle axis. To enable alignment of the measurement direction with the spindle axis, first and second adjusters enable the stylus tip to be moved perpendicular to the spindle axis and the measurement direction when in the first and second stylus attitudes, respectively. An orientation mechanism is provided to rotate the measurement direction of the stylus. A stylus tilt mechanism is provided to tilt the stylus about a tilt axis parallel with the measurement direction.

Abstract: A method of determining a correction parameter for use in effecting alignment of a component of a metrological apparatus in at least one direction is described which includes: positioning an artefact on a support surface of a turntable of the metrological apparatus so that a measurement surface of the artefact is asymmetric with respect to a rotation axis of the turntable in the at least one direction; using a measurement probe of the measurement instrument to make a first measurement of the measurement surface; rotating the turntable; using the measurement probe of the measurement instrument to make a second measurement of the measurement surface after rotation of the turntable; and determining a correction parameter from the first and second measurements.

Abstract: A surface measurement instrument for obtaining surface characteristic data of a sample surface is described. Relative movement between a reference surface and a sample support is caused to occur while a sensor senses light intensity at intervals along a scan path to provide a series of intensity values representing interference fringes produced by a region of a sample surface during said relative movement and from which series of intensity values surface characteristic data can be derived. The sample support is both translatable and tiltable in at least one direction perpendicular to a scan direction so that the sample support can be both tilted to cause the scan path to be normal to the sample surface region and translated to compensate for translation movement due to the tilting.

Abstract: Broadband light is directed along sample and reference paths such that light reflected by a sample surface and light reflected by a reference surface interfere. A mover effects relative movement between the sample and reference surfaces along a scan path. A detector senses a series of light intensity values representing interference fringes produced by a sample surface region during the movement. A data processor processes the intensity values as they are received to produce coherence peak position data and, after completion of a measurement operation, uses this coherence peak position data to obtain data indicative of the height of the surface region. The data processor includes a correlator for correlating intensity values with correlation function data to provide correlation data to enable identification of a position of a coherence peak. A surface topography determiner determines a height of a sample surface region from coherence peak position data.

Abstract: A surface measurement instrument (1) for obtaining surface characteristic data of a sample surface (13) is described. Relative movement between a reference surface (11) and a sample support (15) is caused to occur while a sensor (16) senses light intensity at intervals along a scan path (SP) to provide a series of intensity values representing interference fringes produced by a region of a sample surface (13) during said relative movement and from which series of intensity values surface characteristic data can be derived. The sample support (15) is both translatable and tiltable in at least one direction perpendicular to a scan direction so that the sample support (15) can be both tilted to cause the scan path (SP) to be normal to the sample surface region and translated to compensate for translation movement due to the tilting.

Abstract: An attitude arm mounted to a support arm is rotatable about a pivot. The attitude arm holds a stylus gauge, which generates a signal representing deflection of the stylus in a measurement direction as the stylus follows a surface of a workpiece rotated on a turntable. An attitude switching mechanism allows switching between a first stylus attitude generally aligned with the turntable spindle axis and a second stylus attitude generally aligned perpendicular to the turntable spindle axis. To enable alignment of the measurement direction with the spindle axis, first and second adjusters enable the stylus tip to be moved perpendicular to the spindle axis and the measurement direction when in the first and second stylus attitudes, respectively. An orientation mechanism is provided to rotate the measurement direction of the stylus. A stylus tilt mechanism is provided to tilt the stylus about a tilt axis parallel with the measurement direction.

Abstract: Light is directed along a sample path towards the sample surface and along a reference path towards a reference surface such that light reflected by the sample surface and light reflected by the reference surface interfere. Relative movement is effected between the sample surface and the reference surface along a measurement path and the light intensity resulting from interference between light reflected from the reference surface and regions of the sample surface is sensed at intervals along the measurement path to provide a number of sets of light intensity data values with each light intensity data value representing the sensed light intensity associated with a corresponding one of said regions. The sets of light intensity data are processed to determine a position along the measurement path at which a predetermined feature occurs in the light intensity data for each sensed region and to enhance image data representing the intensity data to facilitate the detection by a user of the interference fringes.

Abstract: A surface measurement instrument (1) for obtaining surface characteristic data of a sample surface (13) is described. Relative movement between a reference surface (11) and a sample support (15) is caused to occur while a sensor (16) senses light intensity at intervals along a scan path (SP) to provide a series of intensity values representing interference fringes produced by a region of a sample surface (13) during said relative movement and from which series of intensity values surface characteristic data can be derived. The sample support (15) is both translatable and tiltable in at least one direction perpendicular to a scan direction so that the sample support (15) can be both tilted to cause the scan path (SP) to be normal to the sample surface region and translated to compensate for translation movement due to the tilting.

Abstract: Light from a broadband source (4) is directed along a sample path (SP) towards a region of a sample surface (7) and along a reference path (RP) towards a reference surface (6) such that light reflected by the region of the sample surface and light reflected by the reference surface interfere. A mover (11) effects relative movement along a scan path between the sample surface (7) and the reference surface (6). A detector (10) senses light intensity at intervals to provide a series of intensity values representing interference fringes produced by a region of a sample surface.

Abstract: A surface profiling apparatus and method. Broadband light is directed along sample and reference paths such that light reflected by a region of a sample surface and light reflected by a reference surface interfere. A mover effects relative movement between the sample and reference surfaces along a scan path. A detector senses a series of light intensity values representing interference fringes produced by the region of the sample surface during the movement. A data processor processes the intensity values as they are received during a measurement operation to produce data indicating the position of a coherence peak, and, after completion of a measurement operation, uses this coherence peak position data to obtain data indicative of the height of the surface region. The data processor includes a correlator for correlating intensity values with a correlation function to provide correlation data to enable the position of a coherence peak to be identified.

Abstract: Light from a broadband source (4) is directed along a sample path (SP) towards a region of a sample surface (7) and along a reference path (RP) towards a reference surface (6) such that light reflected by the region of the sample surface and light reflected by the reference surface interfere. A mover (11) effects relative movement along a scan path between the sample surface (7) and the reference surface (6). A detector (10) senses light intensity at intervals to provide a series of intensity values representing interference fringes produced by a region of a sample surface.