Abstract: A measurement device for determining one or more parameters indicative of the relative position of a first surface of an optical element with respect to a second surface of an optical element. The measurement device includes a supporting device having a supporting surface for supporting the optical element in a first direction. The supporting surface is arranged for abutting one of the first and second surfaces. A measurement unit is arranged for mapping a geometry of the other of the first and second surfaces and for mapping a geometry of the supporting surface of the supporting device by taking measurements of the respective surfaces. A processing unit determines the one or more parameters on the basis of a provided geometry of the one of the first and second surfaces, the mapped geometry of the other of the first and second surfaces and the mapped geometry of the supporting surface.

Abstract: A positioning system for positioning an object includes a stacked stage system movable on a reference surface. The stacked stage system includes a driving system for driving the stacked stage system; a first stage driven along a driving plane parallel to the plane of the reference surface; and a main stage for supporting the object, the main stage arranged on the driven first stage for moving the main stage along the driving plane. The main stage includes a rotary drive system for rotating the main stage with respect to the first stage around an axis parallel to an out-of-plane direction perpendicular to the driving plane. The main stage is movable with respect to the first stage in the out-of-plane direction and further includes a support bearing to movably support the main stage on the reference surface in said out-of-plane direction.

Abstract: An adjustable support for a gantry for a radiotherapy apparatus, wherein the support comprises a base and a mounting member for supporting a gantry, wherein the position of the mounting member relative to the base is adjustable.

Abstract: An adjustable support for a gantry for a radiotherapy apparatus, wherein the support comprises a base and a mounting member for supporting a gantry, wherein the position of the mounting member relative to the base is adjustable.

Abstract: In an optical distance sensor for measuring object surfaces with high precision and comprising an objective lens for focusing a measuring beam to a measuring spot on the surfaces, measuring errors due to tilt of an object surface can be detected by using a pupil monitor, which senses the radiation intensity distribution of the reflected measuring beam effectively in the pupil of the objective lens to generate a tilt signal, which can be supplied to a correction/calibration table to obtain a correction signal, which is suitable for correcting the primary distance measuring signal of the sensor. Especially for a differential confocal distance sensor having pinholes arranged in front of radiation-sensitive detectors, a further order of correction can be obtained by determining optimum position and diameter of these pinholes.

Abstract: In a optical sensor (30) for measuring object surfaces (2) with high precision, measuring errors due to tilt of an object surface can be corrected by using a pupil monitor (72), which senses the intensity distribution of the reflected measuring beam (b?) in combination with a correction/calibration table (76) and use the monitor signal to correct the primary measuring signal (FES) of the sensor. Especially for a differential confocal sensor, a further order of correction can be obtained by determining optimum position and diameter of the pinholes. The measurement beam is directed to an object via a beams splitter cube and an objective that focuses the beam on an object surface. Light is received back from the object surface through the objective and split off by the splitter, from where it is directed to a sensor. In order to increase the measurement range the objective is mounted on an actuator. An interferometer is used to measure the position of the objective.

Abstract: A surface measuring apparatus for measuring a surface shape of an element includes a measurement frame having a mount for mounting the element to be measured, a stage including a rotatable device, the stage being movable in at least a first direction relative to the measurement frame, and a contactless distance measurement device for measuring in the first direction a distance between the measurement frame and a predetermined measurement surface provided on the rotatable device. The apparatus further comprises a second distance measurement device for measuring in a second direction a second distance between the device and a selected position on a surface of an element mounted relative to the measurement frame and a rotation measurement device for measuring an angle of rotation between the first and second direction. In this way, aspheric or free-form surfaces of optical elements can be measured easily in closed loop without introducing abbel-errors.

Abstract: A surface measuring apparatus for measuring a surface shape of an element includes a measurement frame having a mount for mounting the element to be measured, a stage including a rotatable device, the stage being movable in at least a first direction relative to the measurement frame, and a contactless distance measurement device for measuring in the first direction a distance between the measurement frame and a predetermined measurement surface provided on the rotatable device. The apparatus further comprises a second distance measurement device for measuring in a second direction a second distance between the device and a selected position on a surface of an element mounted relative to the measurement frame and a rotation measurement device for measuring an angle of rotation between the first and second direction. In this way, aspheric or free-form surfaces of optical elements can be measured easily in closed loop without introducing abbe-errors.