Abstract: A rotary lapping system and process is disclosed for producing a controlled pressure gradient, including positive and negative lift, when lapping a workpiece coated with an abrasive slurry liquid with a plurality of grinding pads mounted beneath a rotating lap substrate. To obtain positive and negative lift, the grinding pads are tilted with respectively a positive and negative angle of attack, which hydrodynamically reacts with the abrasive slurry liquid to produce the desired lift. The controlled pressure gradient is further varied by decentering the rotation of lap substrate.

Abstract: Thermal actuator apparatus for controlling or adjusting the position of a surface or other object as a function of temperature. The principle of operation is the rate of change, as a function of temperature, in the modulus of rigidity or elasticity of counterbalanced springs of differing materials resulting in a change in equilibrium position. An actuating surface is coupled to the spring system, and its movement with temperature change can be used to change or otherwise control the position of an object.A simple adjustment is also provided to permit varying thermal coefficients of the actuator (magnitude of the response to temperature change).

Abstract: A measuring arrangement is disclosed for measuring the contour of a two or three dimensional surface in which a redundant configuration of distance measuring systems is positioned above the surface being measured. Each distance measuring system monitors distance measurements to a point proximate the surface as the measuring point is moved across the surface. The distance measurements are taken from a sufficient number of points on the surface such that a sufficient quantity of data is obtained to define the system geometry and also to define the position of each measurement point. The data is transformed by recognized mathematical techniques into the coordinate positions of all of the measured points on the surface.In one embodiment for measuring the contour of a three dimensional surface, a tetrahedral arrangement of four distance measuring interferometers includes three interferometers positioned in a planar array above the measured surface and a fourth interferometer positioned at a central apex thereof.

Abstract: A system for precisely determining the position of a beam of incident radiation. In one embodiment in the disclosure the system is utilized in an orbiting, Ritchey-Chretien telescope to determine the precise position of the image of a guide star in the focal plane of the telescope. In that embodiment a first reticle plate, having concentric ring reticle lines, is located at the edge of the tangential focal surface of the telescope and outside of the focal area being used for observation. A second reticle plate, having radial reticle lines, is located adjacent to the first reticle plate at the edge of the sagittal focal surface of the telescope and outside of the focal area being used for observation. A relay lens system and an image dissector tube are positioned behind the reticle plates so that light refracted by the reticle plates is passed by the relay lens system to the image dissector tube. A guide star is imaged on the first and second reticle plates.