Abstract: A method of calibrating a measurement scale in a motorised scanning head using a reference artefact is described. The method comprises the step of rotating a surface sensing device, such as a scanning probe, mounted on the scanning head about at least one axis of the scanning head to move the surface sensing device into a plurality of different angular orientations relative to the reference artefact. A step is then performed of measuring, with the surface sensing device, at least one property of the reference artefact at each of the different angular orientations. An error map or function is then created for at least one measurement scale of the scanning head using the properties of the reference artefact measured and optionally known or calibrated properties of that reference artefact. The method may comprise use of co-ordinate positioning apparatus, such as a co-ordinate measuring machine, to move the scanning head. The reference artefact may comprise a single feature or an array of features.

Abstract: A sample (26) is illuminated by laser light and the resulting Raman spectrum (62) is dispersed at a high spectral resolution along one or more rows or columns of detector elements (60) of a CCD (34). The resulting charge is shifted in a direction Y? and binned in an output register 64 of the CCD. The dispersed spectrum is moved along the rows or columns in a direction X?, synchronously with the shifting of charge in the output register (arrow 72). Thus, data from a given wavenumber in the spectrum continues to accumulate in the output register during the movement. This enables data from a wide spectrum to be collected at high resolution, without the need to subsequently stitch blocks of data together in a computer, even where the CCD is arranged such that row-by-row transfer of charge towards the output register is orthogonal to the direction of dispersion.

Abstract: The transmission of power and/or data from/to a stationary part of a machine tool to/from an accessory mounted in the spindle of the machine tool. A first electrical link or interface provides electrical communication between the stationary part and the spindle, and a second electrical link or interface is provided electrically connected to the first electrical link at the accessory mounting area. The second link is in the form of electrical contacts. An accessory shank for mounting to the spindle of the machine tool, and also to an accessory e.g. in the form of a measurement probe, connected to the said shank.

Abstract: A dimensional measurement probe (10) is mounted in a machine tool (48), which reorientates the probe about at least one axis A. Strain gauges (34) sense when a stylus (20) of the probe contacts a workpiece (50), to produce a trigger signal. False trigger signals may be produced when the probe is reorientated. To overcome this, the reorientation is detected by monitoring changes in the fluctuations of the strain gauge outputs, caused by vibrations of the stylus.

Abstract: A read head for a scale reading apparatus, the head including a light source and an array of photodetector elements, wherein said light source and array of photodetector elements are fabricated in a lattice matched semiconductor compound.

Abstract: A sample positioning stage for positioning a sample to be inspected relative to an optical inspection device. The stage includes a first generally planar body on which a sample to be inspected can be carried and a second body directly coupled to the first body via bearings extending between them which constrain movement of the first body relative to the second body to a first plane that is substantially parallel to the plane of the first body. There is also provided a drive system being selectively operable in a first mode and a second mode.

Abstract: A measurement probe, such as a touch trigger probe, is described that comprises a stylus module attachable to a base module. The stylus module comprising a housing and a stylus holder moveably attached to the housing. The base module comprises a measurement portion for generating measurement data indicative of movement of the stylus holder relative to the housing. The stylus module has an inbuilt failure mode and thereby a substantially predetermined operational lifetime. In one embodiment, the inbuilt failure mode is provided by integrating a battery into the stylus module. Providing a mechanical failure mode in which a component of the stylus module catastrophically fails after a certain amount of usage is also described.

Abstract: A coordinate positioning apparatus has a base a structure and six struts joining the base and the structure. A working volume is defined by the base, structure and six struts. A support member extends from the supported structure. At least one access region is provided into the working volume, the access area being formed between two adjacent struts, the area of the access region being greater than the area between another set of adjacent struts. Access to the working volume is thereby improved.

Abstract: A method is described for measuring a workpiece on a machine tool using an analogue probe having a deflectable stylus. The method comprises the step of taking a workpiece having a nominal surface profile, the workpiece being located within the working area of the machine tool. The machine tool is used to move the analogue probe along a predetermined (known) measurement path relative to the workpiece whilst deflection of the stylus is measured. The analogue probe is moved relative to the workpiece at a speed greater than five millimeters per second and the predetermined measurement path is selected to provide intermittent contact between the stylus and the workpiece.

Abstract: A tool setting or tool analysis device for a machine tool comprises a light source for producing a light beam. A light receiver receives the light beam and produces a signal indicative of the amount of light received. This is analyzed by a main analysis circuit to generate a trigger signal to a machine controller when the beam is at least partially occluded. To provide fail-safe operation should the main circuit not recognize the tool, a back-up trigger signal is produced after a delay by a delay circuit. In one preferred form, the back-up trigger signal may oscillate, providing repeated edges which can ensure fail-safe operation even if the machine controller suffers from a blind window and therefore misses the initial trigger signal.

Abstract: A rotation detection kit, comprising: a beam source; a receiver comprising at least one beam intensity sensor; a polariser device for location in the path of a beam emitted from the beam source and received by the beam sensor; and a modulator. The modulator is configured to modulate at least one of i) the beam source and ii) a beam emitted by the beam source to create a discretely varying polarisation orientation thereby defining first and at least second temporally spaced beam portions. The temporally spaced beam portions are incident on the polariser device and the beam sensor and have substantially identical profiles and at least an initial common propagation axis toward the polariser device.

Abstract: A measurement probe (12, 110, 250), such as a touch trigger or analogue probe, is described that comprises a deflectable stylus portion (14) and a wireless communications unit (18) for transmitting stylus deflection data to a remote probe interface (20, 104, 254). The wireless communications unit (18) is arranged to transmit digital data packets comprising stylus deflection data and a probe identity code. The wireless communications unit (18) allows said probe identity code to be set by a user. The measurement probe (12, 110, 250) may communicate with an associated probe interface (20, 104, 254) over a radio frequency (RF) spread spectrum link (106).

Abstract: Apparatus for delivering therapeutic agents to the central nervous system of a subject is described. The apparatus comprises at least one intracranial catheter and a percutaneous access device. The percutaneous access device comprises a body having at least one extracorporeal surface and at least one subcutaneous surface, the body defining at least one port for connection to an implanted intracranial catheter. The port is accessible from the extracorporeal surface of the device, but is provided with a seal such as a rubber bung between the lumen of the port and the extracorporeal surface. The percutaneous access device may have more than two ports and/or a flange. A method of implanting the percutaneous access device is also described.

Abstract: Apparatus for measuring displacement between two members. A scale is provided on one member and has an incremental pattern with at least one reference mark embedded in it. A read head is provided on the other member and comprises a periodic diffraction means for interacting with a light pattern modulated by the incremental pattern on the scale to produce interference fringes having movement relative to said readhead responsive to said displacement, first detecting means for detecting the movement of the interference fringes, imaging means for imaging the reference mark and second detecting means for detecting the image of the reference mark.

Abstract: An object detector apparatus. The object detector apparatus comprises a receiver which is configured to receive a signal from an object having a repetitive motion, in which the signal repeats at a frequency that is dependent on the frequency of the repetitive motion of the object. The object detector apparatus further comprises an analyser which is configured to sample a signal received by the receiver according to a first set of sampling parameters into a first sampled data set, and to produce an output based on a comparison of the first sampled data set with at least one previously sampled data set. The analyser is also operable to sample a signal received by the receiver using a second set of sampling parameters which differs to the first set of sampling parameters into a second sampled data set, and to produce an output based on a comparison of the second sampled data set with at least one previously sampled data set.

Abstract: A spectroscopic analysis method in which spectral data of mixtures obtained from a plurality of points on a sample surface are resolved into component spectra and concentrations. A new alternating least squares multivariate curve resolution technique is presented which iteratively resolves the components. The technique starts from an initial estimate that the spectral values of a first component of the sample are all equal (an ‘empty model’), and resolves that component. Then successive further components are iteratively resolved, from initial ‘empty model’ estimates of those components and from previously resolved spectra. In the common case where the main component is present in nearly pure form in the data set, this empty modelling technique results in more accurate resolution of the components. This is due to the ability of the technique to resolve the pure spectra of minor components without modelling concentrations of the main component into them.

Abstract: A method is described for calibrating apparatus comprising a measurement probe (4) mounted on a machine, such as a machine tool. The machine is arranged to capture machine position data (x,y,z;70;80) indicative of the position of the measurement probe and the measurement probe is arranged to capture probe data (a,b,c;72;82) indicative of the position of a surface relative to the measurement probe (4). The measurement probe (4) may be an analogue or scanning probe having a deflectable stylus (14). The first step of the method involves moving the measurement probe (4) at a known speed relative to an artefact (30;40,42) whilst capturing probe data (a,b,c;72;82) and machine position data (x,y,z;70;80). In particular, the measurement probe (4) is moved along a path that enables probe data (a,b,c;72;82) to be captured that is indicative of the position of two or more points on the surface of the artefact relative to the measurement probe (4).

Abstract: A method and apparatus for measuring a surface using a surface sensing device mounted on a scanning head on a member of a coordinate positioning apparatus. The coordinate positioning apparatus may be operated to produce relative movement between the scanning head and the surface profile and the scanning head includes a drive for producing rotational movement of the surface sensing probe about one or more axis. The coordinate positioning apparatus is driven to provide relative movement between the member and the surface profile in a circular path and the probe head is driven to move the surface sensing device about said one or more axes, such that the surface sensing device maintains a nominally constant lead angle. The motion of the coordinate positioning apparatus and probe head is synchronous.

Abstract: A method of calibrating an articulating probe head comprising the steps of measuring an artefact of known dimensions with the workpiece sensing probe mounted on the articulating probe head, in which the articulating probe head is unlocked. An error functional map is generated corresponding to the difference between the measured and known dimensions of the artefact. Subsequent workpieces are measured with the articulating probe head unlocked and the corresponding correction applied. The true dimensions of the artefact may be determined by measuring it with a probe mounted on an articulating probe head in which the axes of the articulating probe head are locked. A mechanical lock is provided to lock the axes of the articulating probe head.

Abstract: A pivot joint assembly is described that includes a multi-axis revolute joint portion and a ball joint portion. The multi-axis revolute joint portion provides rotational movement about two or more revolute axes that substantially intersecting at an intersection point. The ball joint portion comprising a ball located in the vicinity of said intersection point. The pivot joint assembly allows separate coupling of load members and metrology members to one or more platforms. A hexapod co-ordinate measuring machine including such pivot joint assemblies is also described.