Abstract: A two-axis measurement system for use with an article under test (AUT) is provided with a thermal control system to maintain the measurement system at a stable temperature. The thermal control system may be use a temperature-controlled fluid, such as liquid or gas, conducted through the measurement system. The measurement system further comprises a field probing sensor that is adapted to be positioned at a plurality of points spaced from the AUT to perform a measurement of the AUT. The probing sensor is manipulated by at least a first member extending in a first axial direction and a second member extending in a second axial direction perpendicular to the first axial direction. A near-field measurement of the AUT is performed by moving the field probing sensor in a pattern in front of the AUT to sample the RF energy of the AUT at a plurality of points. Internal passageways provided through the first and second members permit communication of the temperature-controlled fluid therethrough.

Abstract: A high precision alignment apparatus is provided that utilizes a semiconductor laser device, such as a laser diode, to provide a source laser beam. The alignment apparatus permits the division of a pair of beam components from the source laser beam useful for either linear or planar alignment. A centroid measurement between the beam components provides a corrected reference point that accounts for the inherent instability of the source laser beam to yield a high level of alignment accuracy. For linear alignment purposes, the beam components are collinearly directed. In the alternative, for planar alignment purposes, the beam components may be either collinear or directed in opposite directions, and rotated to sweep respective planar regions. The laser alignment apparatus is capable of providing a level of accuracy heretofore achievable only with gas lasers, while maintaining the economical attributes of commercial semiconductor laser diodes.

Abstract: A two-axis measurement system includes a structural support frame having at least two horizontally disposed parallel rails defining a length of the structural support frame at opposite sides thereof. The support frame further defines a test space between the opposite sides. A bridge extends perpendicularly between the rails and is capable of controlled movement along the rails over the length of the structural support frame. A first probe carriage carried by the bridge permits controlled movement along a span of the bridge. A vertical tower is coupled to the bridge orthogonally with the rails, and a second probe carriage is carried by the vertical tower permitting controlled movement along a height of the vertical tower. The first probe carriage is selectively moveable within a horizontal test plane defined in a first axial dimension by the rails and in a second axial dimension by the bridge by cooperative movement of the bridge and the first probe carriage.

Abstract: A high precision alignment apparatus is provided that utilizes a semiconductor laser device, such as a laser diode, to provide a source laser beam. The alignment apparatus permits the division of a pair of beam components from the source laser beam useful for either linear or planar alignment. A centroid measurement between the beam components provides a corrected reference point that accounts for the inherent instability of the source laser beam to yield a high level of alignment accuracy. For linear alignment purposes, the beam components are collinearly directed. In the alternative, for planar alignment purposes, the beam components may be either collinear or directed in opposite directions, and rotated to sweep respective planar regions. The laser alignment apparatus is capable of providing a level of accuracy heretofore achievable only with gas lasers, while maintaining the economical attributes of commercial semiconductor laser diodes.

Abstract: A three-axis motion tracking interferometer for use with an article under test (AUT) is provided for measurement and correction of position errors between the AUT and a near-field probing sensor due to thermal drift. The probing sensor is positioned at a plurality of points relative to the AUT to perform a phase front measurement of the AUT. Periodically, the probing sensor is positioned at a subset of the plurality of points, the subset being sufficient to define a geometric surface, such as a plane, cylinder, or sphere. A distance change measurement is performed between the AUT and the probing sensor at each of the subset of points, and three-axis components of relative motion between the AUT and the probing sensor are calculated based upon the distance change measurement. The phase front measurement of the AUT can then be corrected based upon the three-axis components.

Abstract: A wide range straightness measuring system of the present invention accurately determines lateral and angular displacement of a probe carriage of a cartesian robot. The system includes a laser aligned with an x-axis rail of the cartesian robot system which generates a laser beam having two polarization components. A pentaprism beamsplitter is disposed on an x-axis carriage aligned with the laser. The beamsplitter orthogonally splits the laser beam into an x-axis reference beam and a y-axis reference beam. An x-axis interferometer receives the x-axis reference beam and determines a relative position value of the probe carriage measured along the x-axis. A y-axis interferometer receives the y-axis reference beam and determines a relative position value for the probe carriage measured along the y-axis. A beam monitor receives a polarized multiplexed output of the y-axis interferometer and monitors the lateral shift of the energy centroids of the beam polarization components.