I-tek, Inc.

United States of America As Represented by the Secretary of the Air Force

Allen H Greenleaf

William C Bradley

John T Watson

Roger K Lee, Jr

Robert L Milamed

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.

Computer controller optical surfacing (CCOS) lap pressure control system

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).

Thermal actuator apparatus

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. A retroreflector is placed adjacent to the measured surface to define the measuring point, and is selectively movable across the measured surface. A tetrahedral truss is positioned above the measured surface, and each interferometer has a beam steering head at one corner of the truss to aim the interferometer beam at the retroreflector during movements thereof. Each interferometer further includes a servo control system for controlling the beam steering head to maintain the interferometer beam aimed at the retroreflector.

Self calibrating contour measuring system using fringe counting

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. Light in the star image which is imaged onto either an apex or a groove in the reticle plates is split into separate beams in dependence upon the exact position of the image relative to the apex or groove. The position of the guide star image is precisely located first in a coarse position mode and secondly in a fine position mode. In the coarse position mode the image dissector tube aperture is scanned to find the overall locations of the separate beams, and the deflection signals of the image dissector tube at those locations determine the particular apex or groove in each reticle plate upon which the star is imaged. In the fine position mode the amount of light in each of the separate beams formed by the reticle plates is measured by the image dissector tube in a photon counting mode. This determines the exact position of the star image relative to the particular apex or groove in each reticle plate upon which the star image is incident.

Growing community of inventors

Pownal, ME, United States of America

Allen H Greenleaf