Abstract: The invention provides a collapsible seat suitable for forming from a sheet material. The seat includes a seat panel, a back panel linked to the seat panel along a first fold line, and a support panel linked to one side of the back panel via a first web defined by second and third fold lines. The support panel is adapted to be linked to another side of the back panel via a second web partially defined by a fourth fold line. The seat also includes a reinforcement panel having one end linked to the support panel along an eighth fold line and an opposite end. The reinforcement panel is adapted to be positioned generally horizontally and under the seat panel in use. The reinforcement panel includes twelfth and thirteenth fold lines intermediate the seventh fold line and the support panel such that the reinforcement panel is divided into first, second and third portions. The first and third portions are substantially identical in size.

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: A sample positioning stage for positioning a sample to be inspected relative to an optical inspection device, including a first generally planar body on which a sample can be carried and a second body directly coupled to the first body via at least one rigid bearing and at least one resiliently compliant bearing provided between the first and second bodies. The first and second bodies are preloaded against each other in a dimension substantially parallel to the plane of the first generally planar body via the bearings. The stage also includes a motorized drive system operable to drive the first and second bodies relative to each other in the first plane toward a demanded relative position received from a position input device, and a position sensing device on at least one of the first and second bodies, for providing a measure of the relative position of the first and second bodies.

Abstract: A Raman spectroscopy system has a filter arrangement comprising two filters (16, 26A) in series, to reject light of the illuminating wavenumber from the scattered light of interest. The filters are tilted and have different characteristics for light of first and second different polarisation states. To counter this, the filters are arranged so that their respective effects on the respective polarisation states at least partially cancel each other out. This may for example be done by arranging their tilt axes (32, 34) orthogonally to each other.

Abstract: An optical slit comprises two blades 40,42 which define a slit between them, each blade being independently movable. This enables both the slit position and the slit width to be adjusted. The slit may be aligned with the center of a light beam by aiming the light beam at a detector, traversing at least one edge of the slit across the beam path, measuring the intensity of transmitted light at the detector for each position of the slit, and feeding back a signal which adjusts the slit position for maximum light throughput. The width on the optical slit may be selected by placing the slit in the path of the light beam and measuring the light transmitted at the detector, calculating the percentage of light transmitted for that slit width and feeding back a signal which adjusts slit width to obtain the desired amount of light throughput.

Abstract: An optical slit comprises two blades 40,42 which define a slit between them, each blade being independently movable. This enables both the slit position and the slit width to be adjusted. The slit may be aligned with the centre of a light beam by aiming the light beam at a detector, traversing at least one edge of the slit across the beam path, measuring the intensity of transmitted light at the detector for each position of the slit, and feeding back a signal which adjusts the slit position for maximum light throughput. The width on the optical slit may be selected by placing the slit in the path of the light beam and measuring the light transmitted at the detector, calculating the percentage of light transmitted for that slit width and feeding back a signal which adjusts slit width to obtain the desired amount of light throughput.

Abstract: The invention relates to a method and apparatus for focusing structured image such as a laser spot. A method for determining the degree of focus of such a structured image are disclosed whereby: an image is provided at a photosensitive array formed from a plurality of elements; the position of the image is determined; for an element of the array a weighting is assigned according to the position of that element relative to the position of the image; the intensity of the image at the element is determined; a value is produced for the element dependent on its weighting and the intensity of the image thereat. In addition the values of the plurality of elements are summed and one overall focus value is found which is indicative of the degree of focus of the image. This value is used to search for and maintain best focus and methods for achieving this are disclosed also. Apparatus is shown in which a microprocessor and a controller are used to perform the methods disclosed.